The narwhal Monodon monoceros is almost a real-life fantasy creature. But not only due to its historical connection with the legendary unicorn – after all, a whale with an enormous tusk growing out of its head is much more fabulous than most legendary animals from ancient bestiaries which don’t even exist. If we would know narwhals only from fossils, we would surely deeply regret that we could never see this marvelous beast alive. But this creature – one of the most bizarre cetaceans which ever evolved – is an extant species and a good reminder that we still live alongside many incredible animals which can easily compete with the most extraordinary beasts of prehistoric times. There is a lot to say about narwhals, and it would be probably easy to write even a whole book only about their iconic tusks. I recently wrote about their rarely shown vestigial right tusks and a bizarre hybrid between a female narwhal and a male beluga.
Much about the exact function and use of the large torqued tusks still remains an enigma. Many assumptions about the functional use were based on examinations of the anatomy of the tusks, their surface, abrasions and wear patterns. Actual observations of active tusk usage are still extremely rare. A recent video shows that it has apparently really an assisting function for hunting however. But as usually only males possess fully developed tusks, it seems obvious that it has a role for sexual competition as well. Broken tusk tips found embedded into the skull bones of other males indicate that narwhals use their enormous teeth for physical interactions with other males as well.
One of the weirdest phenomena you can find within the cetacean literature are cases of broken narwhal tusk tips inside broken narwhal tusk tips. Errmmm…. What!? To avoid further confusion, I will show you some examples from which I took photos at the University of Copenhagen Zoological Museum.
There are three of such tusks on display, however one of them is just a short fragment.
There is a considerable part of the tips broken off, and you can see the cavity which was originally filled by the pulp. And within this cavity is a plug of torqued ivory, which perfectly fills the opened tusk.
There are also longitudinal fractures and some bending of the tusk around the plug, and it looks like it was forcefully pierced into the broken end.
So what happened here? Was there a narwhal with an already broken tusk tip seeking help by Dr. Monodon who used its own tusk in an altruistic attempt to fill the aching fracture with its own tusk and break the tip off? Or to stay more seriously, could it be that it happened by accident that a male narwhal rammed its thin tusk tip during an interaction in the already fractured tusk of an opponent? Or could it be that narwhal bulls touch each others tusks and one tip became by chance plugged into the opening of the fractured tusk?
It really appears that something like this was happening, and the very existence of not just one but three such cases in a single museum could indicate some never observed behavior. However, as interesting as the idea of narwhal bulls accidentally practicing some sort of endodontic treatment to each others tusks appears, those broken tusks have a quite different background. It started with a tusk fracture, perhaps when a narwhal hunted fish on the sea bottom and had a traumatic collision with a rock. The tip of its tusk broke off, leading the whale quite likely in severe agony for some time. If something similar happens to a human, for example when an incisor is fractured and the pulp becomes exposed, it is just a matter of time until the pulpal tissue becomes infected by bacteria and necrotizes, at least if it is not properly treated. Under totally aseptic conditions – something only possible under laboratory conditions with totally germ-free mice or rats in an isolated environment – the exposed pulpal tissue can produce again new dentine at the fracture and seal the wound.
Fractured narwhal tusks can heal in a similar way without the usual necrotizing of the whole pulp and the resulting fatal conditions for the tusk. Perhaps this is due to the extreme size of the pulp and the many blood vessels within that lead to a better exchange of immune cells and lead also to a faster regeneration of the ruptured tissue. The seawater which always surround the wound might help as well. But admittedly, this is nothing but my personal speculation. It’s noteworthy that exposures of pulps in orcas – something quite common in captive specimens and those which specialize in hunting sharks and skates with highly abrasive skin – lead to necrosis of the pulps as well.
But narwhals can heal such fractures. When the cells at the outer area of the pulp-wound manage to produce a new formation of dentine the fracture is sealed. But this layer is apparently not tightly attached to the inner walls of the tusk. For this reason the ongoing apposition of reparative dentine forms over time a twisted plug which is pressed out of the pulp cavity, forming over time a tiny new tusk. And this is what appears to be the broken tip of a tusk rammed into the open pulp. The crack and bending of the fractured end were possibly also a postmortal artifact when the tusk dried.
I found the information about the reparative dentine of the broken narwhal tusks in the 2003 edition of Walker´s Marine Mammals of the World by Ronald M. Nowak. I was sadly not able to track down the original sources of Reeves, R.R., and S. Tracey.1980. Monodon monocers. Mammalian Species, no. 127, 7 pp and Newman, M.A. 1978. Narwhal. which was cited in Haley, D., ed. 1978. Marine mammals of eastern North Pacific and Arctic waters. Pacific Search Press, Seattle, 138-44. If anyone reading this has access to this original sources or any other information about this topic, I would be quite interested.
Technically, all modern birds are dinosaurs, descendents of a lineage of theropods that evolved complex feathers and the ability to fly. But to be honest… most of them don´t really look very „saurian“ anymore. Those fancy feathers, toothless beaks and stumpy tails – usually coupled with a small overall size – just make it sometimes hard to accept their family background. Even if you know that filaments and feathers were in fact a quite common thing among dinosaurs, even if you are well aware of the fact that a lot of dinosaurs were of quite small body size and even if you are quite familiar with the evolutionary origins of modern birds you can still struggle to accept birds as real living dinosaurs. But sometimes you get a reminder about their theropod heritage, and a glimpse into a time when their ancestors were still not trying to conquer the airspace. For example if you take a close look at one of the largest extant birds, the emu Dromaius novaehollandiae. Don´t look at its pretty blue head or the shaggy double-feathers. Just look down at its staggering feet.
There is probably really nothing closer to a non avian theropod foot in the modern world. This is how people even today usually imagine a classical theropod foot. If you forget the rest of the body, you can really easily imagine that it belongs to something much more primordial, somethat that had still jaws lined with teeth, arms with big claws and a long tail. Of course there are some anatomical differences, for example the missing hallux of the emu. But it is still pretty awesome that something still walks the earth on such feet.
The ostrich has even bigger feet, but they are unique and utterly bizarre by nearly every standard, the feet of the cassowary are also pretty cool, but with their elongated claws still somehow too non-standard and not really that similar to any dinosaur feet. It it really frustrating that we missed some of the most spectacular birds that ever lived – the giant moas of New Zealand and the elephant birds of Madagascar – for just a few centuries. The feet of this giant birds were quite likely even closer to the feet of a medium-sized non-avian theropod than anything alive today.
I wrote some time ago about the incredibly polymorphous scales on the feet and legs of the ostrich. If we look at the feet of the emu, we can also see some quite interesting anatomical features as well.
Some of the scales on the backside of the tarsometatarsus form massive conical structures. I have to admit that I have no idea what function they have. But those cone-scales are surely something nobody would expect to have ever existed by looking at the bare bones of a fossil. I can´t help, but they could look pretty cool on the legs of a non-avian theropod as well.
Should I ever get my hands on the foot of an emu, I will try to make a similar listing of its scale types and scale arrangements as I did for the ostrich. I can´t emphasize enough how important and helpful it is to look at the anatomy of living animals to reconstruct species which we know only from their bare bones. You will discover a lot of things which you possibly never noticed before, like in the case of the ostrich and emu those weird scale shapes, the volumous pads on the downside of the toes or the way in which the nails abrade. It will also remind you that we are still living in a world full of amazing animals, and that even many familiar species are much more fascinating and unusual than most people think.
I recently visited the Royal Ontario Museum at Toronto, a monumental museum about zoology, paleontology, history, archeology and ethnology. Among the many wonderful objects in the exhibition about ancient Egypt, one artifact caught my eye in particular. It was a very large fishing hook with a massive leader of thick wire elements – all made of bronze.
Here is another photo which shows the hook with some large bronze knifes and baskets to give you a better idea about its size. It was about the size of a hook for big-game-fishing in the sea, or for the largest freshwater fishes like big sturgeons or giant catfish. I have to admit I have a penchant for old and exotic fishing gear, and this one is really one of the coolest ones I have ever seen. From a technical aspect I really admire the work of the ancient smith who made it, the well thought-out construction which helped to avoid a twisting of the line which made it also possible to connect the comparably thin hook with a very strong line. The twisted eyes of the hook and the chain elements provided a maximum of durability. The shape of the hook is not just an U like the much simpler hook on the left, but is highly similar to modern hooks. The diameter in the middle of the curvature is especially thick and slightly flattened to withstand heavy loading. Whoever forged this some thousand years ago – he knew exactly what it needs to catch a monster fish.
Today we find nearly identical constructions for shark hooks in which a massive swivel protects the line when the shark is spinning, and a short chain against the sharp shark teeth. Here is an example from the Deutsches Jagd-und Fischerei-Museum (Museum für hunting and fishing) at Munich, from a temporary special exhibition about sharks:
You can see an even more similar example of a historical shark hook which includes also a chain here.
The African continent is particularly poor in big freshwater fish, and only few species grow to sizes bigger than a meter. There is however one big exception, a fish which reaches enormous dimensions, the nile perch Lates niloticus. This behemoth can exceed lengths of 1,8 m and weights well over 100 kg, making it one of the heaviest freshwater fishes of the world. As usual there are a lot of anecdotes and hardly confirmable dates about much bigger specimens, what makes it quite hard to give more precise sizes and weights.
Even before this species was introduced to many bodies of water in which it was originally not native (with desastrous effects, like in Lake Victoria) it had a very large range, which included the nile in North Africa. The ancient Egyptians were well familiar with this fish, and there are even cases known of mummified nile perches, like this specimen in the Egyptian Museum at Cairo. Fish was caught with nets, harpoons and also hook and line (which included simple rods but also handlines), and it was an important source of protein. Most of those fish were however comparably small, species like cyprinids, tilapias or smaller and medium sized catfishes. Catching the really big nile perches was probably not that easy as it required special gear. The fabrication of this hook was probably already a lot of work and bronze was still very valuable even at small amounts at that time.
Bones of large nile perches were also found among other animal relics at archeological sites, sometimes in form of waste, sometimes as burial objects. Some of them include relics of really huge specimens, like several nile perches from the necropolis of Elephantine which were about 1,8 m in life. One particular specimen was even about 1,9 m. There were also a lot of nile perch bones found at the temple of Satis, which included several very large specimens, including one of about 1,9 m. It´s noteworthy that this is still not bigger than the largest modern day nile perches from the big lakes in their more southern range. Today such huge specimens are no more found at Egypt anymore, but it seems that they were considerably more common in the past, and the ancient fisherman obviously managed to catch them.
As nile perches usually prefer comparably deep water, they were likely rarely caught with harpoons, and it seems likely that they were also no common targets for neting, at least not the big ones. So angling with hook and line in big game style was likely the most efficient way to target particularly big specimens, which had also surely a considerable worth. The ancient Egyptians called the nile perch „the fighter“, what also possibly indicates its behavior when it was caught with hook and line. Those fishermen had nothing even remotely comparably to the modern fibreglas rods and reels, but just handlines to catch those enormous fish which could weigh considerably more than an average human.
If you want to learn more about fishes and fishing in ancient Egyptian art and culture, take a look at those links: 1, 2, 3.
BOESSNECK, J. und von den DRIESCH, A. (1982): Studien an subfossilen Tierknochen aus Ägypten. – Münchener Ägyptol. Studien, 40:58, München-Berlin.
I wrote some time ago about zoological treasures in archeological, ethnological and historical museums. Today I want to share some quite interesting examples of such „treasures“ which I have seen in the Oceania exhibition of the Ethnological Museum of Berlin. What you see here is a boar’s mandible from Vanuatu, a group of islands located in the South Pacific Ocean east of Australia.
The obviously most striking feature of the mandible are the extremely long circular tusks. They are so long that their tips have grown into the lower jaw and penetrated the bone.
You can see how how the infection caused by the tusk tips lead to a degradation of the surrounding bone and a thickening of the bone behind. The ingrown tusks acts like foreign bodies and cause a constant local infection. In the living animal they must have pierced the cheeks as well.
This is an extracted lower boar tusk, which shows how the tooth formed a full circle, with the tip just next to its own apical end.
Here is another example, but this boar luckily died before the tusks could impale its jaw.
For a considerable time I was wondering how this circle tusks could grow to such grotesque shapes. It was obvious that it resulted from a lack of abrasion with the upper tusk, which usually limit the lengths of the lower tusks while forming constantly sharp edges. Sometimes we see similar cases as a result of misplaced teeth which lead to a missing abrasion between upper and lower tusks. I covered such a case of a pot-bellied pig which had highly elongated lower tusks. The extremely shortened skull and jaws of pot-bellied pigs often result into various tooth displacements. But those jaws from Vanuatu belonged to pigs which were still quite primitive compared with most modern breeds, with long heads similar to wild boars and with well grown teeth.
So how could they grow this bizarre circle tusks? Were those pigs possibly selected for dental misplacement that make such teeth growing“naturally“? The answer is no, those boars were actually results of a surgical procedure which made their tusks growing into this unnatural shapes. Their upper tusks were extracted at early age, so the natural curve of the lower tusks could grow longer and longer without being abraded by an antagonistic upper tusk. The boars selected for this were kept isolated and fed with special food, and apparently they were also castrated. This was likely to avoid accidental fractures of the tusks during fights with other boars and to let them grow better even with the chronic inflammation of the cheeks and jawbone.
But why did Vanuatuans want boars with circle tusks? The answer is pretty simple, because breeding boars with circle tusks was literally like breeding money. Those circle tusks were not just used for decoration or jewelry but as money as well. And they longer they were, the bigger their worth was. They were used to make jewelry like necklaces, as decoration for sculptures and for certain rituals. You have to keep in mind that it takes several years until a boar has grown a circle tusk, and even more for a spiral tusk. During this whole time it needs extra food, and even more than a normal pig, which can also forage in the wild. But when the boar is finally killed and its tusks removed, they are worth a little fortune. I highly recommend to watch this short documentary about the role of circle tusks in modern Vanuatu. You can also see a living boar with circle tusks which pierce its cheeks. There are also a few incredibly extreme spiraling tusks from an ethnological collection featured as well.
You can get an idea about the importance of circle boar tusks if you take a look at the flag and the coat of arms of Vanuatu.
The whole museum exhibition at Berlin was moved to another location after my last visit and I don’t know if those specimens will be still exhibited in the new museum. It was the same exhibition which also included the mislabeled Kogia mandible about which I already wrote.
This is mainly an updated version of a blog post which I already wrote in 2009 in German. You can find the original post here.
Kürzliche erregten neue Forschungsergebnisse um einen bizarren Hybriden aus Narwal (Monodon monoceros) und Beluga (Delphinapterus leucas) weltweite Aufmerksamkeit. Er wurde nach Angaben eines grönländischen Inuit namens Jens Larsen 1986 oder 1987 in der Disko-Bucht im Westen Grönlands geschossen, und wies unter anderem einige äußerst ungewöhnliche Besonderheiten der Zähne auf. Der Wal soll grau gefärbt gewesen sein, und seine Brustflossen denen eines Belugas, die Schwanzflosse dagegen eher der eines Narwals geähnelt haben. Larsen beschloss aufgrund des ungewöhnlichen Aussehens des Wals dessen Schädel aufzuheben. Etwa zur gleichen Zeit sollen in der Gegend noch zwei ähnliche Exemplare geschossen worden sein, von denen jedoch eines versank und nicht geborgen werden konnte. Der Kopf des dritten Exemplars wurde zum Skelettieren an der Küste ausgelegt, allerdings niemals wiedergefunden, so dass als einziges physisches Relikt der von Larsen aufbewahrte Schädel verblieb.
Als 1990 der dänische Zoologe und Walexperte Mads Peter Heide-Jørgensen den Schädel auf dem Dach eines Werkzeugschuppens im grönländischen Kitsissuarsuit entdeckte, erkannte er gleich dass es sich dabei um etwas wirklich außergewöhnliches handelte. Larsen stiftete den Schädel für weitere Untersuchungen, woraufhin dieser nach Kopenhagen gebracht wurde. Seine Anatomie zeigte Ähnlichkeiten zu jener von Narwalen und Belugas, wies aber auch eine Reihe von Merkmalen auf, die völlig einzigartig waren, und sich von allen anderen bekannten Walen unterschieden. Anhand der teilweise verwachsenen Suturen (Knochennähte) von Oberkiefer und Zwischenkiefer lies sich erkennen dass es sich um ein erwachsenes und bereits älteres Tier gehandelt hatte. Beim Vergleich mit den Schädeln von Belugas und Narwalen lag der Schädel in seinen Proportion etwa zwischen beiden Arten, in seinen Größendimensionen allerdings etwas über deren durchschnittlicher Größen. Bereits vor einigen Jahren wurde für den Hybriden der Begriff „Narluga“ geprägt, welchen ich hier auch verwenden möchte.
Besonders ungewöhnlich waren allerdings die Zähne, welche sich sowohl in Anzahl, Form als auch Größe von jenen von Belugas und Narwalen unterschieden. Belugas besitzen im Ober-und Unterkiefer je 8-11 Zähne auf jeder Seite.
Die Zähne von Belugas sind zapfenförmig, und nutzen sich vor allem im Oberkiefer oft auf typische Weise löffelförmig ab.
Beim Narwal dagegen besitzen üblicherweise nur die Männchen einen einzigen funktionellen Zahn, bei welchem es sich um einen massiv modifizierten linken oberen Eckzahn (er entstammt dem Oberkiefer und nicht dem Zwischenkieferknochen, ist also kein Schneidezahn) handelt, welcher außerhalb des Mauls durch die Haut der Oberlippe wächst.
Normalerweise ist er nur auf einer Seite ausgeprägt, während der deutlich kleinere und auch nicht gedrehte rechte Eckzahn üblicherweise im Kieferknochen verbleibt. Bei weiblichen Narwalen finden sich derartige im Kiefer verbleibenden Eckzähne sowohl rechts als auch links.
Eine derartig extrem ausgeprägte dentale Asymmetrie wie bei Narwalen ist einzigartig unter den lebenden Säugetieren. Gelegentlich finden sich allerdings auch Exemplare mit einem auch rechts teilweise oder sogar voll ausgebildeten Stoßzahn, oder auch Weibchen mit ein oder sogar zwei Stoßzähnen. Das eigentliche Maulinnere ist dagegen völlig zahnlos. Gelegentlich finden sich auch kleine verkümmerte Zähne an der Basis des Stoßzahns im Knochen des Oberkiefers, welche allerdings nicht durchbrechen.
Der Schädel des Wals aus der Diskobucht hatte dagegen ursprünglich im Oberkiefer auf jeder Seite je 5 und im Unterkiefer je 4 Zähne, von denen allerdings ein oberer und ein unterer postmortal verloren gingen. Aufgrund von Abrasionen und ihrer Position im Knochen kann man davon ausgehen dass sechs oder sieben der zehn Oberkieferzähne zu Lebzeiten in die Mundhöhle ragten.
Die drei oder vier vordersten Zähne lagen horizontal im Knochen und sind nie in die Mundhöhle durchgebrochen. Ihre sehr langgestreckte gerade Form erinnert etwas an die nicht durchbrechenden Stoßzähne von Narwalen, die für diese typische Verdickung an der Wurzelspitze fehlt allerdings. Die vorderen Zähne ließen sich nicht ohne Beschädigung des umliegenden Knochens entfernen, anhand von Röntgenaufnahmen ließ sich ihre Form und Länge aber ermitteln. Dies ergab eine stattliche Länge von 25,6 cm für den linken ersten Oberkieferzahn und 24,8 cm für den rechten ersten Oberkieferzahn. Die zweiten hatten immerhin noch eine Länge von 19,6 cm und 21,5 cm, während die weiter hinten liegenden immer weiter an Länge abnahmen, dafür aber auch eine mehr oder weniger starke Krümmung aufwiesen. Nach Angaben von Jens Larsen hatte der Narluga welcher im Wasser verloren gegangen war, auch sichtbare vordere Zähne im Oberkiefer.
Die Zähne im Unterkiefer zeigten ebenfalls eine Reihe von Besonderheiten. Zunächst waren sie ausgesprochen groß und massiv gebaut, deutlich größer als die Zähne von Belugas. Auch der gesamte vordere Bereich des Unterkiefers war äußerst breit und massiv. Aufgrund ihrer Form und Größe müssen die unteren Zähne sogar noch bei geschlossenem Maul teilweise sichtbar gewesen sein. Einige waren merkwürdig verdreht und zeigten vage Andeutungen von Längsrillen, vergleichbar den Stoßzähnen von Narwalen. Die ungleichmäßigen Abrasionsmuster ließen ebenfalls erkennen dass sie sich während des Wachstums leicht um die eigene Achse gedreht haben müssen.
Die vier rechten und ersten drei linken Unterkieferzähne standen alle recht dicht beieinander, waren von ähnlicher Größe und waren deutlich noch vorne geneigt. Der leider nicht mehr vorhandene vierte linke Zahn saß dabei aber deutlich weiter hinten im Kiefer als sein Pendant auf der rechten Seite, zudem konnte man anhand des leeren Zahnfachs erkennen dass er nicht nur deutlich kleiner gewesen sein muss, sondern auch sichtlich nach hinten geneigt war.
Als der Schädel erstmals untersucht wurde, war seine genaue Identität noch nicht abschließend geklärt. Ursprünglich wurde auch ein Narwal mit starken dentalen Anomalien für möglich gehalten, die Möglichkeit eines Hybriden allerdings auch schon in Betracht gezogen. Kürzlich vorgenommene Untersuchungen seines Erbgutes durch eine Forschergruppe um Eline Lorenzen vom Zoologischen Museum Kopenhagen konnten nun tatsächlich die Vermutung um seine hybride Herkunft bestätigten. Zudem konnte ermittelt werden dass es sich bei diesem wirklich ungewöhnlichen Exemplar um eine Kreuzung aus einem weiblichen Narwal und einem männlichen Beluga handelte. Die Beschreibung der beiden anderen mutmaßlichen Hybriden durch Jens Larsen ist auch insofern bemerkenswert weil sich hierbei die Frage stellt ob diese alle unabhängig voneinander gezeugt wurden, oder ob sie möglicherweise alle die selbe Mutter oder den selben Vater hatten. Ohne verbliebene körperliche Relikte dieser beiden Exemplare wird sich diese Frage allerdings nie beantworten lassen. In der Diskobucht kommen sowohl Narwale als auch Belugas vor, und sie ist auch eine der wenigen Gegenden in welcher beide Arten auch zu ihrer jeweils unterschiedlichen Paarungszeit anzutreffen sind. Gelegentlich schließen sich einzelne Belugas auch Gruppen von Narwalen an, aber auch einzelne Narwale in Belugaschulen kommen gelegentlich vor, etwa ein junges und möglicherweise verirrtes Narwalmännchen welches sich im kanadischen Sankt-Lorenz-Strom den dort lebenden Belugas angeschlossen hat. Es gibt eine ganze Reihe von dokumentierten Hybriden zwischen verschiedenen Walspezies, sowohl unter Zahnwalen wie Delfinen oder Schweinswalen, als auch von Bartenwalen.
Die Interaktion der unterschiedlichen Erbanlagen ist wirklich erstaunlich. Besonders dahingehend dass jene Gene welche beim Narwal das Größenwachstum und die Torsion des Stoßzahns steuern sich in stärkeren Maße auf die Zähne des Unterkiefers ausgewirkt haben als auf jene im Oberkiefer. Es wäre sehr interessant zu wissen ob, und falls ja wie, sich bei der umgekehrten Kreuzung zwischen einem Narwalmännchen und einem Belugaweibchen die Genkombinationen anders ausgewirkt hätten.
Eine weitere erstaunliche Erkenntnis ergab die Untersuchung der Kohlenstoff-und Stickstoffisotpe im Kollagen des Knochens. Demnach ernährte sich der Narluga nicht von den gleichen Beutetieren wie Belugas oder Narwale, sondern erbeutete vor allem Fische in tieferen Wasserschichten. Möglicherweise bevorzugte er aufgrund seiner ungewöhnlichen Bezahnung bestimmte Beute die er nur in tieferen Wasserschichten finden konnte.
Seit ich 2007 zum ersten Mal von diesem bizarren Wal gelesen habe, war ich fasziniert von ihm. Da die ursprüngliche Veröffentlichung von Mads Peter Heide-Jørgensen damals noch nicht im Internet frei verfügbar war, schrieb ich ihn an und bekam freundlicherweise eine digitale Version von ihm zugesendet. Die gescannte Version des Drucks beinhaltete eine ganze Reihe von interessanten Fotos, allerdings leider in sehr unzufriedenstellender Bildqualität. Zudem gab es einige weitere Fotos des Schädels im Internet, viele seiner Details ließen sich aber auch bei ihnen nicht vollends erkennen. Ein Jahrzehnt später, im Frühsommer 2017, bekam ich die Möglichkeit den Narlugaschädel im Original im Archiv des Zoologischen Museums in Kopenhagen zu begutachten, und seine Anatomie vor Ort zu studieren. An dieser Stelle möchte ich mich noch einmal ganz herzlich bei Eline Lorenzen und auch vor allem bei Daniel Klingberg-Johanson dafür bedanken den Schädel und viele andere faszinierende Stücke im nichtöffentlichen Archiv des Museums ansehen zu können.
Was mich ganz besonders interessierte, war wie dieser Wal wohl zu Lebzeiten ausgesehen haben könnte. Da lediglich der isolierte Schädel, die Verwandtschaftsverhältnisse und die sehr vage Beschreibung von Jens Larsen vorhanden waren, stellte sich hier eine Aufgabe,welche viel eher der Rekonstruktion eines nur von Fossilien bekannten ausgestorbenen Tieres vergleichbar war (etwa meiner Basilosaurus-Rekonstruktion). Bisher gab es keinerlei Bilder welche einen Eindruck vermittelten wie der Hybrid einmal ausgesehen haben könnte (es gab eine einzige Darstellung, welche allerdings lediglich eine digitale Kombination aus einem Narwal und einem Beluga darstellte, und weder die Zähne noch die beschriebene Farbe berücksichtigte), was seine Rekonstruktion umso interessanter machte.
Da das einzigartige Gebiss das hervorstechendste Merkmal des Narlugas war, sollte es bei der Rekonstruktion auch entsprechend gut erkennbar sein. Daher entschloss ich mich direkt ein Bild des komplett artikulierten Schädels aus einer vor längeren Zeit erfolgten Pressemitteilung als Basis zu verwenden. Bei Zahnwalen im Allgemeinen und bei Gründelwalen wie dem Narwal und Beluga im Speziellen wird der Schädel von einer großen Menge Weichgewebe umschlossen. Vor allem die Melone, das Echolotorgan welches oberhalb des Schädels sitzt, nimmt einen sehr großen Raum ein. Dazu kommen noch die Bereiche in denen die komplexen Strukturen zum Blasloch führen, sowie die Lippen und natürlich das dicke Unterhautfettgewebe. Eine sehr hilfreiche Illustration zum besseren Verständnis der Anatomie eines Belugakopfes kann man hier sehen.
Bei Belugas kommt noch hinzu dass sie durch Muskelkontraktion die Form ihrer Melone in gewissem Rahmen verändern können, was das Heranziehen von Referenzbildern noch problematischer machte, denn selbst bei ein und demselben Individuum kann auf verschiedenen Bildern die Melone unterschiedlich geformt sein. Belugas besitzen auch für Wale ungewöhnlich gut ausgebildete und bewegliche Lippen. Das alles musste bedacht werden, selbst wenn hier selbstverständlich einiges an künstlerischer Freiheit einfloss. In seiner Kopfform steht der Narluga nun zwischen jenen der beiden Elternarten, mit den eher stärker verrundeten Formen des Narwals aber einer schlankeren Halspartie und etwas voluminöseren Oberlippen um dem Belugaerbe gerecht zu werden. Den fehlenden letzten Zahn auf der linken Unterkieferseite rekonstruierte ich anhand der Größe und Ausrichtung des leeren Zahnfachs im Kiefer. Man sieht nun ganz gut die starke Asymmetrie in der Position und Form der Zähne im Unterkiefer. Bei der Pigmentierung des Maulinneren verwendete ich das Foto eines Narwalmauls als Referenz. Bei Walen findet sich nicht wie sonst bei Säugern üblich eine klare Abgrenzung zwischen dem normalerweise von Schleimhaut ausgekleideten Maulinneren und den von Epidermis bedeckten Lippen.
Bei der Körperform stützte ich mich auf die skelettalen Proportionen von Belugas, um anhand des Schädels die dazugehörigen Dimensionen des Körpers festzulegen. Auch hier versuchte ich einen Mittelweg zwischen den zwei Elternarten zu finden. Bei Narwalen ist der Körper sehr stromlinienförmig und glatt, während Belugas einen sehr stark vom Körper abgesetzten Kopf und seitlich am Körper liegende Fettpolster und Längsfalten besitzen. Auch haben sie noch einen wahrnehmbaren, leicht eckigen Rückenkiel, während bei Narwalen die Rückenflosse bis auf eine Linie von kleinen, kaum erkennbaren Hauttuberkeln zurückgebildet ist. Belugas haben größere und deutlich breitere Brustflossen als Narwale, weshalb ich sie aufgrund der Beschreibung Larsens auch als Referenz verwendete. Bei der Schwanzflosse dagegen orientierte ich mich an den stark halbkreisförmig ausgebildeten Flossenlappen des männlichen Narwals. Interessanterweise findet sich bei Narwalen ein Geschlechtsdimorphismus bei der Form der Schwanzflosse, welche allem Anschein nach mit den hydrodynamischen Auswirkungen des Stoßzahns zusammenhängt.
Die Farbe des Narluga wurde als grau beschrieben, und unterscheidet sich insofern deutlich von der weißen, beziehungsweise weiß-schwarz marmorierten Farbe von Belugas und Narwalen. Allerdings sind bei beiden Arten die Jungtiere noch grau gefärbt, und es ist nicht völlig ausgeschlossen dass bei dem Hybriden möglicherweise atavistische Anlagen zum Vorschein kamen, welche aus der Zeit stammten, als ihre Vorfahren noch nicht in polaren Gebieten lebten, und vermutlich auch noch nicht von weißer Grundfarbe waren. Daher bekam der Narluga ein Farbschema welches sich an den Jungtieren der beiden Elternarten orientierte. Im Kopf-und Halsbereich deutete ich eine leichte graue Marmorierung an, welche mehr einem jungen Narwal entspricht, der hintere Körperbereich dagegen der homogeneren Farbe junger Belugas. Zudem nahm ich mir die kreative Freiheit die Brustflossen etwas dunkler vom Körper abzusetzen, wie es in stärkerer Form bei Narwalen der Fall ist.
Um den Hintergrund noch ein bisschen interessanter zu gestalten fügte ich einen kleinen Schwarm Polardorsche (Boreogadus saida) ein, eine Fischart welche auch in der Disko-Bucht lebt, und sowohl vor Flussmündungen bis hinab in Tiefen von 900 m vorkommt. Diese Fische stellen auch eine wichtige Nahrung für Belugas und vor allem Narwale dar.
Insgesamt arbeitete ich an der Rekonstruktion mehrere Monate, und trotz mancher Ungewissheiten und künstlerischer Freiheiten bestimmter Details hoffe ich doch sehr dass sie zumindest einen realistischen Eindruck dieses außergewöhnlichen Wals vermitteln kann.
Fontanella, J. E., Fish, F. E., Rybczynski, N., Nweeia, M. T. and Ketten, D. R. (2011). Three-dimensional geometry of the narwhal (Monodon monoceros) flukes in relation to hydrodynamics. Mar. Mamm. Sci. 27, 889-898.
Heide-Jørgensen, M. P. & Reeves, R. R. Description of an anomalous Monodontid skull from west Greenland: A possible hybrid? Mar. Mamm. Sci.9, 258–268 (1993).
Nweeia, M.T., et al. 2009. Considerations of anatomy, morphology, evolution, and function for narwhal dentition. The Anatomical Record 295, 6: 1006-1016.
M. Skovrind et al. Hybridization between two high Arctic cetaceans confirmed by genomic analysis. Scientific Reports. Vol. 9, June 20, 2019. doi:10.1038/s41598-019-44038-0.
There are awesome news about one of the most unusual cetaceans in modern history, an enigmatic hybrid between a narwhal (Monodon monoceros) and a beluga whale (Delphinapterus leucas).
The specimen was shot at Disko Bay, Greenland, in 1986 or 1987 and the skull – the only remaining relic – collected there in 1990 and sent to Copenhagen. I´ve been fascinated by this freak of nature since I´ve read about it for the first time in 2007. From all the photos available at that time I tried to make a reconstruction of it, but I was not really happy with it. In 2017 I had finally the chance to examine the original skull of this specimen in the archives of the Zoological Museum at Copenhagen, what gave me some highly worthy insights into its extremely weird anatomy. Besides the skull only a few vague descriptions of the living animal were known, so dealing with it was like dealing with the remains of a prehistoric animal only known from fossils. This made it of course even more interesting to make a reconstruction of the living whale, which was subsequently termed „narluga“ by some people.
I want to thank here Eline Lorenzen and especially Daniel Klingberg-Johansson for the chance to visit the non-public archive where the skull is located. The public exhibition of the Museum has many incredible and absolutely priceless specimens (more about some of them in a future blogpost), but as usual a lot of the really good stuff is in the archives. Thanks again Daniel for this awesome tour to the museal catacombs!
In this blogpost I want to give you some more background information which is known about the narluga, and how I tried to give the skull a face and a body. As I already wrote it was shot in 1986 or 1987, by an inuit hunter named Jens Larsen. The correct date is not known, as Larsen who didn´t remember the year for sure. It was discovered by Mads Peter Heide-Jørgensen on the roof of a toolshed at Kitsissuarsuit, which is located at the mouth of Disko Bay, West Greenland. Larsen had perceived it unusual enough to save the skull and donated it for further examination. He sadly could not give much more information about it, unless that it had flippers which resembled those of a beluga and a fluke more similar to those of a narwhal, but a coloration which was not white like a beluga or white and dark-gray mottled like a beluga but uniformlys gray and unlike those of those two species. What was even more interesting was the fact that he remembered that there were two additional specimens, which were shot as well. One was lost during the hunt (modern inuit shot belugas and narwhals usually with guns, so a lot of them just sink to the bottom of the sea and are lost), the head of the other one was saved and left near the water for maceration, but never retrieved.
After the skull was sent to Copenhagen, it was examined and compared to various skulls of belugas and narwhals from the collection of the Zoological Museum. It exhibited several unusual features. It was somewhat larger and more elongated than the means of the skulls used for comparison. Its sutures of the premaxilla/maxillare were fused, what indicated that the specimen was already comparably old. The most bizarre feature of it was however the dentition. It was totally unlike any other known whale.
It had originally ten upper and eight lower teeth, from which one of the maxillary teeth was already lost when the skull was found. In the living narluga, six or seven of the upper teeth were likely exposed inside the cavity of the mouth, as they showed also signs of abrasion. The three most anterior teeth however apparantly never erupted through the gums and remained mainly within the bone. Their appearance was extremely strange, very thin, long and horizontally orientated within the bone, a bit similar to the unerupted vestigal teeth of narwhals but lacking their typical knog at the apical end. The more distal teeth were shorter and more curved. According to Lars Jensen, the specimen which sank and was lost had even some visible protruding upper teeth.
The mandibular teeth in contrast were all eruted, very large and massive, assymetrical in shape and orientation. In the living animal they were likely visible even when the narluga had its mouth closed. Two of those teeth show unusual curving and slight twisting which must have occured during growth, and even longitudinal grooves vaguely similar to those seen in erupted narwhal tusks.
The most distal tooth on the left side was very small and much more posteriorly located then the fourth tooth on the right side. It was sadly lost, but the orientation of the tooth socket indicates quite clearly that it was pointing backwards.
At the time of its first examination it was still not known if it really was a hybrid between a narwhal and a beluga, or just a really unusual narwhal with extreme dental anomalies. Genetic examinations however clearly showed that it really was a male hybrid, with a narwhal mother and a beluga father. Another really interesting result from the examination of carbon and nitrogen from the bone collagen revealed that the narluga differed in diet from both belugas and narwhals. The fish on which it preyed were apparantly from more benthic regions than those usually consumed by narwhals and belugas. Perhaps this diet resulted from the unique dentition of this individual, which made it harder to hunt and catch the more common prey animals of its parental species.
When I worked on the reconstruction of the living animal, I tried to take everything known about it into account. The shape of the skull, the orientation and abrasions of the teeth and the description of the external features like flippers, fluke and coloration, as well as the anatomy and life appearance of Monodon and Delphinapterus. I gave the narluga the head-to-body-ratio of a beluga and tried to make its external body shape intermediate between those of a narwhale and a beluga. Narwhals have streamlined bodies, but belugas have a very distinct neck area and weird fat deposits at their belly area.
By far the most difficult part of the reconstruction was the head and mouth. Narwhals and belugas differ in several aspects of their cranial soft tissue. Belugas have – quite unusual for extant cetaceans – quite fleshy and flexible lips, which can be moved into a lot of shapes. Even more problematic was their ability to change the shape of their melon area, because this made it really hard to find a good reference with which I was happy, since every beluga photo looks different – even if it´s the same indivudual but with different melon shapes. I made many tries until I found something with which I was mainly happy and still somewhat intermediate between narwhals and belugas. I didn´t gave it beluga lips, but made them at least a big more pronounced than those of narwhals.
The upper teeth are not visible here (they usually never are visible from lateral views in most odontocetes). I directly used the original shape of the lower teeth of the articulated skull from an earlier press release to get them as correct as possible and to show also such features like the partial torquing and spiraling. The fourth left tooth was missing, so I had to reconstruct it from the position and size of its tooth socket, which show that it was much smaller than the other mandibular teeth, assymetrically distally located and backwards-pointing.
I nearly missed to portray a minor but important detail until the very end, the blowhole which is nearly invisible as this position. But luckily I just remebered to draw it before I sent the final version to Eline Lorenzen.
The coloration was described as gray and unlike those of narwhals or belugas. This is not that unusual that hybrids don´t just show intermediate patterns or colors of their parental species but unique new traits. Because both belugas and narwhals are comparably uniformly gray at young age, I used them as reference for the color of the narluga, with a very slight mottling reminiscent to those of juvenile narwhals. Because it was an older specimen, I gave it a few scars, because it is very likely that it received some from rocks and ice during its life.
To make the scenery a little bit more atmospheric I added a small swarm of polar cods (Boreogadus saida) in the background. This species occurs in the area where the narluga was shot, from river mouths to depths up to 900 m, what makes it a very well fitting faunal element, especially as it´s a very common food item for both belugas and narwhals.
I made the flippers mainly based on the large pectoral fins of belugas, but somewhat lesser developed, but slightly darker than the rest of the body as seen in narwhals. The fluke shows the unusual „backwards“ shape of male narwhals (those of females look more normal), just somewhat lesser expressed. Like all my other digital art projects (for example my recent Basilosaurs), this was made with GIMP. The whole project took several months until it was finally finished, but it was also a really interesting and exciting project. A lot of it was surely speculative, even if based on some known known facts. Perhaps anytime we will see another, perhaps even living narluga, which will show how close my rendition was to the true life appearance.
Heide-Jørgensen, M. P. & Reeves, R. R. Description of an anomalous Monodontid skull from west Greenland: A possible hybrid? Mar. Mamm. Sci.9, 258–268 (1993).
Mikkel Skovrind et al. Hybridization between two high Arctic cetaceans confirmed by genomic analysis, Scientific Reports (2019).
Last year I was involved into a fantastic project, the production of the wildlife documentary „Into the Forest: Reptiles & Amphibians“ by my good friend Bryan Maltais.He made already several other shorter documentaries, including the award-winning production „Metamorphosis“ about the amphibian life in a wetland in Colorado. But this was by far his biggest project. I want to write here about the filming and the background of „Into the Forest“, which is now also available on Amazon Prime, both in English and German.
Bryan spent his early youth with his German mother and American father in Germany but later grew up in the U.S. Over the decades he regularly came back to visit his second home and the German part of his family. During those vacations he regularly visited a forest near Denkendorf, a village not far away from Stuttgart, in the southwest of Germany. It was this forest where he came for the first time into contact with the European herpetofauna and other native animals. He later studied wildlife biology and developed a particular interest into reptiles and amphibians. Over the years Bryan became a professional nature and landscape photographer and produced several documentaries, mainly about reptiles and amphibians.
Bryan Maltais at Mills Lake inside Rocky Mountain National Park
We met for the first time in 2014 after I discovered his documentaries on YouTube and realized that Denkendorf is in fact comparably close to my own place of residence. Over the years we met for several more times for herping tours and I introduced Bryan to various other interesting locations like the habitat of my local green lizard (Lacerta viridis) population or the Black Forest with its melanistic European adders (Vipera berus).
Bryan taking close-up photos of a green lizard
But „Into the Forest“ became a much bigger and much more extensive project than just a few tours to the woods. Bryan spent three whole months in Germany to document the rise of nature from the last snow of march to the early summer in june. He was filming for nearly every single day and sometimes even during night, and when he wasn’t filming he worked on editing and cutting the videos.
To produce a high quality documentary he used a 4k camera so you can also enjoy it on a big screen in TV quality. He made slow motion and fast motion videos, underwater-and night vision footage and made also some amazing landscape videos with a drone (which had tragically a fatal accident, luckily all the important drone footage was already filmed at this time).
View over the Black Forest. Screenshot from „Into the Forest“
During this three months we met as often as I could to show Bryan several more interesting locations like a pond which is especially well suited to observe mating common toads (Bufo bufo). One particular experience was a tour during a rainy night to a small valley just quite close to where I live. This area is a very good location for one of the most charismatic European amphibians, the flamboyant fire salamander Salamandra salamandra. Admittedly I was never there after dusk, and our tour topped easily everything I’ve ever seen during a salamander herping tour. We saw so many fire salamanders that we couldn’t even count all of them, but all in all we’ve seen about 60 specimens. In this area the populations of the striped fire salamander Salamandra salamandra terrestris and the spotted fire salamander Salamandra salamandra salamandra overlap and both forms also interbred. As a result of this we encountered an enormous range of different patterns. We also found a specimen which just caught an earthworm, a pair which was mating and best of all several females just giving birth to their larvae.
Filming fire salamanders during a rainy night is not exactly the most comfortable thing you can imagine
The fire salamander also plays a key role in the documentary, but not just for its charming appearance but also to raise awareness about the dangers of the chytrid fungus Bsal which entered the European continent from Asia over the amphibian pet trade. Bsal already eradicated whole fire salamander populations in Belgium and the Netherlands, and has already reached northern Germany. Sadly, it is likely to continue spreading even further through Europe.
Female fire salamander giving birth to its larvae. Photo by Markus Bühler
Another nightly tour brought us to a local population of European tree frogs (Hyla arborea). The loudness of their croaking was just incredible. This was for me also the very first time to see European tree frogs, as this species has sadly become extremely rare, mainly as a result of a lack of fitting habitats and small periodically draining ponds where they can successfully spawn. I was also quite surprised to learn about this population which is also quite closely located to some of the other areas where Bryan filmed.
European tree frog, photo by Markus Bühler
Of course the wonderfully exotic-looking (and in this case allochthonous) green lizards (Lacerta bilineata – or is it viridis? Things are complex here) of the local population here around were included as well. Bryan could even film a mated pair, and the drone footage provided some great views of their habitats within the centuries old vineyards.
Another reptile we hoped to find remained however elusive. The year before we made a trip to the Black Forest (which is also only about an hour to drive from here) and were able to find two specimens of melanistic European adders.
Melanistic form of the European adder, the „hell adder“
But this year we had sadly lesser luck. During our first trip to the Schliffkopf, one of the highest elevations of the Black Forest, it was despite the early time of spring extremely hot, well over 25 Celsius. On some places there was still half a meter of snow, but the heat of the sun was just too much for the adders.
Not a tundra area at Scandinavia but an upland plain at the Schliffkopf. Photo by Markus Bühler
At least we could observe some particularly nicely colored European grass frogs (Rana temporaria) in the act of mating, and this sequence was also included into the final documentary.
Mating grass frogs. Photo by Markus Bühler
We made later two further trips, but every time the weather conditions were against us. At the second tour to the Schliffkopf mountain it was quite the opposite of the last time, it was very cold with a lot of wind and fog, but next to no sunshine. Again pretty bad conditions for adders. However the fog over the forest provided some spectacular landscape shots.
Fog and clouds over the Black Forest. Photo by Markus Bühler
The view from the slopes around the Schliffkopf is really great, you can even see the Alsace behind the river Rhine.
Bryan looking to France
Our last tour to the Black Forest lead us to Kaltenbronn, an area with several bogs where we found the two adders the year before. Sadly all we found that time was a single freshly road-killed adder.
Bog area at Kaltenbronn. Photo by Markus Bühler
A photo of me from our more successful adder-tour in 2017:
One highlight was also a herping excursion to Croatia. There would be so much to say about the many things which we have seen there, but this would be way too much here. We made a tour from the island of Krk to to the very southwest of the Croatian mainland, down over Istria to the island of Cres and again back to Krk. We saw various interesting reptiles, birds and a lot of really unusual invertebrates and spectacular landscapes. We didn’t find as many reptile species as we hoped, especially snakes and scheltopusiks (Pseudopus apodus) proved to be quite elusive and hard to find. I spied only a few of scheltopusiks at the first day at Krk, but it was not possible to take any photos. One species for which we had especially big hopes to see it was the horned adder (Vipera ammodytes), one of the most venomous snakes of the European continent.
Horned adder, Krk.
It was still a lot if luck involved, but during our systematic search I could detect a tiny horned adder between some stones. This enigmatic little snake was surely one if our greatest finds during the excursion.
Bryan and the horned adder, island of Krk, Croatia.
To have at least a more southern cousin of the European adder on screen, it was also included within a short segment about our excursion. There would be still so much more to say, but I will make a break here, in hope to write anytime a future blogspot about our tour to Croatia. You can see some more photos on Bryan’s website.
A considerable part of the documentary was filmed in the Schönbuch forest, a large forest area near Tübingen. The deep and wide-ranging woods provided various interesting locations for filming, from game enclosures with red deers and wild boars to large ponds full of tadpoles. Germany is quite densely populated and even most of the nature reserves are in one way or another altered by human activities. In many cases this already happened centuries ago, so the landmarks of human activities are often deeply interwoven within the surrounding landscape.
One of the big ponds of the Schönbuch forest. Photo by Markus Bühler
One especially nice remnant of human culture was also included, the old monastery of Bebenhausen which is located just in front of the Schönbuch forest. Surrounded by centuries old wooden framework houses, its gothic architecture, ancient walls and old towers made it also a perfect location for drone footage to show the full range of the complex.The monastery was founded in 1190 and after the reformation it was among others used as a hunting lodge and the late residence of the last king of Baden-Württemberg in the early 20th century.
The old monastery of Bebenhausen. Photo by Markus Bühler
We visited also the Alter Aichwald („old oak forest“) near Denkendorf where Bryan made much of the filming of fire salamanders and other featured amphibians. We were there already years ago on our first fire salamander tour.
Fire salamander at Alter Aichwald
Bryan showed me the big badger den which he discovered and where he could make some great footage with a game camera.
I know many of those locations for nearly my whole life and have countless wonderful memories about them. To see them now in high quality documentary feels nearly somewhat surreal, especially as I was on site during many of filming sequences. I learned a lot of new things and made many new experiences, and it makes me really proud that I could contribute a little bit to this wonderful documentary. Bryan did really an amazing job to produce the whole documentary himself. He did all the cutting of the scenes, the selection and arrangement of the background music, the script (which I translated and adapted for the German version, entitled “Der magische Wald: Reptilien und Amphibien) and the digital enhancement of certain scenes. Normally such documentaries are made by whole production teams or even specialized companies.
Screenshot from „Into the Forest“
„Into the Forest“ became a really wonderful documentary especially as it focuses on animals which get despite their fascinating lives usually only little media coverage. I think it will be also quite interesting to see for everyone interested in animals, no matter if you’re European and familiar with some of the featured animals or if you are living anywhere else on the world. I could imagine that for non-European watchers it could be especially interesting to learn about some of the enigmatic animals which still dwell in such a non-exotic area, and also about the surrounding landscapes and history of Southern Germany.
You can read more about the documentary at the official website Into the Forest.
Bryan has also many of his nature and animal photos on MacroPhotoBug, wildernessshots and his instagram and Facebook-page. His documentaries are available on his YouTube channel.
Many thanks also to all who wrote suggestions, ideas and constructive criticism during the editing of “Into the forest”.
If you read a comic or watch a cartoon which includes any crocodiles or alligators, you will notice that they are nearly universally green. The same applies to crocodiles in books for children, on logos or sometimes even drawings in nature books. But are crocodylians really green? To answer this question, it is important to take a look at the various modern crocodylians which includes the crocodiles, the alligators the gharials.
If you are only familiar with „normal“ crocodylians like Mississippi alligators, nile crocodiles or saltwater crocodiles, you will be possibly surprised by the diversity of colors and patterns, especially if you also take a look at the juveniles which are often much more contrast-rich than older specimens.We find near white and full black, a big range of grey, but also many shades of yellow and brown which can be even reddish. And of course there are combinations and mixes of all of them as well as fully black patterns.
But what about green? This is not that easy to answer. We clearly see not a single crocodylian as green as the eponymous green lizard or the green iguana. At best we find something that falls somewhere in the range of greenish, for example in Nile crocodiles. But even here it seems to be not a real propper green but more a mix between yellow and grey that appears green.
It’s quite interesting that even ancient Egyptian artists already sometimes exaggerated this to a much stronger green.
The Nile crocodile Crocodylus niloticus and the West African crocodile Crocodylus suchus were also the first crocodylians which became known to European cultures. The Romans even imported some crocodiles from North Africa to exhibit them or to slaughter them in gladiator fights. We still even find some surprisingly realistic artistic depictions of crocodiles from Roman times, which were quite likely made by people who had actually either seen then themselves or had at least very good references. But besides those we find also some much more grotesque depictions as well.
not really that surprising that later medieval depictions of
crocodylians were usually just vaguely naturalistic at best. But the
green color was still a comparably common feature. During the
renaissance, when cabinets of curiosities became chic, taxidermy
crocodylians were quite popular items for such collections. Trading
connections and the discovery of the New World and other exotic areas
lead at that time to a tremendous increase of new animal discoveries
and a much better understanding of the natural world. The imported
taxidermy specimens of crocodylians were surely not green what makes
it even stranger that the stereotype of the green crocodiles managed
to persist in art.
If we look at other species we find some other crocodylians besides C. niloticus which have a vague greenish appearance. But even if we keep the slight ability of color change of some species in mind, we still don’t see anything even remotely close to a real green. The only green crocodylians which we find in the real world have their coloration from a layer of algae.
It’s hard to say how much such algae-covered crocodiles, caimans and alligators contributed to the stereotype. In some cases it’s not even that obvious anymore that the original coloration is altered by a fine layer of tiny water plants and even species which have normally not even a vaguely green touch can appear to be of that color.
I could imagine that this really was a factor which contributed to the cliché of the green crocodiles. Many early travelers and explores could probably see crocodylians only from some distance and usually in the water.
put the initial question – are crocodiles really green – in a
nutshell, I would say that some are perhaps a little bit.
But yet they are still far away from the common stereotypes. That makes it even harder to understand that we still see reconstructions of prehistoric crocodylians with truly comicesque green colors. I am fully aware that we cannot rule out the possibility that prehistoric crocodylians could have had a wider range of colors, especially as they filled many more ecological niches than the remaining modern lineages. But makes it really sense to reconstruct those forms with a color we see in no extant crocodylian species? I really don’t think so. I have to emphasize here that I am refering here only to amphibious crocodylians and crocodyliformes, and not the various terrestrial forms which had totally different ecologies. On a sidenote, I am also not refering to marine forms, which had probably again quite different color schemes and patterns, but I also really doubt that any of them was green either.
The range of colors we actually see in modern crocodylians gives paleoartists already so many possibilities to create interesting new color schemes and patterns, that it’s not even necessary to include green at all. I wrote in an earlier blogpost about a certain tendency to depict marine reptiles with extremely elaborate color scheme and why this is somewhat problematic and contrary to what we see in most bigger marine vertebrates.
Mark Witton gave recently a really interesting and thought-provoking talk about monsterization in paleoart. This included also the importance to depict prehistoric animals not like semi-fantastic beasts but as real animals to enable people to really understand how this were once living organisms and not concept art for a sciene fiction movie.
Don’t get me wrong, I really don’t say that we should now depict anything in grey, brown or yellowish colors like all the dinosaurs in the first Jurassic Park movie (except the imaginary frill of the Dilophosaurus of course…). But we should – even if we create new patterns and color schemes – still not forget to see how real animals are looking in life. In the case of extinct crocodylians we even have the chance to see some of their relatives still alive – something impossible for many other prehistoric animals without any extant relatives.
So, does it make sense to reconstruct extinct crocodylians and crocodiliformes with colors we don’t find in any extant species? Not really. Even more so when it comes to prehistoric crocodylians which actually are still comparably closely related with modern forms and share even a similar ecology.
why I would not reconstruct an animal like Purussaurus, Mourasuchus
or any other amphibious crocodylian or crocodiliform with a green
coloration which is more pronounced than the dirty greyish-yellow of
Nile crocodiles. I really think there is a reason that no modern
crocodile, alligator, caiman or gharial is really green, no matter if
they hunt fish, turtles or zebras and no matter if they live in a
jungle river, a swamp area like the everglades or a savannah habitat.
I was recently able to acquire two fresh partial ostrich legs from a breeder. This was a perfect chance to study the external and internal anatomy of this giant bird’s legs and feet. I could take a really close look at things that I could neither see in a living ostrich in a zoo nor in a mounted taxidermy specimen. For me this was particularly interesting because I gould get firsthand data about anatomical details for sculptures and illustrations for which it’s very hard to find good references.
The feet of the ostrich are weird, even grotesque compared with normal bird feet. They are quite likely the most derived feet of any extant flightless bird. Functionally they are closer to the feet of an ungulate than to those of a typical avian. The first toe is enormous in size and has a wide and nearly hoof-like nail whereas the second toe is much shorter, flattened and has no more claw at all. Instead it has a very tough and robust skin with soft pads at the proximal bones. Those pads are made of rounded fat deposits which are embedded within the surrounding connective tissue. The second toe reminded me a lot on the soft-padded toes of camels. The dissection and removal of the skin from this toe without a lateral cut was just awful, and I am not willed to do this ever again.
Before you continue reading I have to apologize for not using that many references and super-correct descriptions for the underlying anatomy of the foot and leg. I really wanted to focus particularly on the scales, and the very large number of photos here made it already quite time-consuming to write the blog post. As there was also a lot of discussion about this topic, I also hoped to finish it today. If I find some more time, I´ll try to make an edited version with some more background information. I also realized when I wrote this that I had lesser usable photos than I thought, because the quality of some of the photos I took was not good enough.
What I found particularly interesting was the large variation of different scale types on different parts of the leg. Of course this is especially good to see in an ostrich, simply because it is such a huge bird. I think that even many people who are familiar with birds are not really that aware of the complex patterns and differences of the scales on bird legs. I write this all also not only to tell you something about the anatomy of modern birds but also as a help for paleoartists to provide some references which could be helpful for depictions and sculpted reconstructions of dinosaurs and prehistoric birds. Luckily we have several really good fossils and also some very nice track fossils which show us partial skin patterns of certain dinosaurs. I was quite surprised to see nearly the whole range of all known dinosaur scale variants on this single ostrich foot and lower leg, plus some more which I’ve never seen in a fossil.I thought it would be best to start at the base of the legs and go further down up to the toe tips.
There was an area of extremely thick skin at the ankle area. The scales were highly keratinized and formed some kind of knee pad to protect the underlying parts.
You can also see how a lot of dirt was pressed in-between the scales of the ankle area.
This is the ankle area in side view. You can see the „knee pad“ area and the highy wrinkled and much softer and thin skin behind it.
This photo shows the scales at about the midle of the leg. If you take a close look you can already see how the scales differ at the front side and back side.
Some more photos from the middle of the leg:
I found this scales especially interesting, as they have quite well pronounced bumps.
Those lower legs consists nearly only of bone and giant sinews wrapped in skin.
You see here the area where large irregular and somewhat thickened scales are forming into the pronounced scutes.
On this photo you can see the large scutes which are located in the area above the foot. At this little segment you can already see a whole lot of different sizes and shapes of scales.
The skin at the backside of the tarsometatarsus is very soft and loose and forms very big folds to allow enough flexibility.
Here´s again another view of the whole foot.
The big scutes don´t form a line up to the toe tip but are interrupted by smaller scales…
…just to form again large scales over the big toe. You can again see an interruption of the scutes where they break into a double line of smaller scutes.
The largest scutes are at the proximal end of the toe and form big shields.
Now the smaller lateral too is really weird. You can see thick and polygonal scales with highly keratinized surfaces on the left which are similar to those at the ankle area. But also their transformation into the large scutes on the upper sides of the toe and rounded, smooth scales with large areas of skin in-between on the sides.
Another detail of the photo above.
Now let´s take a look at the bottom of the foot. The nail is very short, wide and blunt and feels nearly like a hoof.
Most of the scales on the sole of the toes are very small and highly keratinized and form dense pads.
But what the heck is going on here? The scales at the centre of the foot form into bizarre upwards turned structures.
Now this looks really super-gnarly. Can you imagine how the feet of a large theropod or even sauropod could have had similar or even more extreme scale formations?
The area behind this spikey pads is again formed from very small, very irregular scales.
This really large number of very different and highly specialized scales is an important reminder that even fossilized patches of dinosaur skin show us still only a small fraction of their bodies. We also have to keep in mind that this ostrich leg is just an ostrich leg and should not be used as a universal reference. The sizes, patterns, shapes and functions of the scales on bird legs are much more diverse than many people think and we can be next to sure that there were also a lot of different scale types present in dinosaurs, even if they were usually not as elaborate and dragonesque as in some modern squamates. As this topic evoked a lot of interest in recent online discussions about dinosaur skin I decided to write some more blog posts dedicated to this, especially to feature some more non-standard scale patterns on bird legs.
Basilosaurus was just big in the news when a new study about its feeding habits and the predation on young Dorudons was published. This is probably a good time to feature a new reconstruction of the „king lizard“ that I just finished. Originally this was not even made to jump on the Basilosaurus bandwagon but I was looking for an animal which I could use for a certain little art project, and it just fitted perfectly, mainly due to its extreme body proportions. But it became quickly more and more complex and the initial little illustration evolved into much more. I wanted to make a reconstruction which included the aspects which I already discussed in length in my earlier blogposts about the cranial soft tissue of archaeocetes and the highly likely presence of facial vibrissae in this animals. Now I want to explain in detail how and why I reconstructed my Basilosaurus in the way I did.
I used the famous skeletal drawing of Basilosaurus isis by Kellog (1936) as main reference, however not the original but a modified version by Cameron McCormick with the updated number of vertebrae based on the examination on the vertebrea counting of three overlapping skeletons (Gingerich et al 1990) and a paper by Zalmout et al. 2000.
As a result of this, this Basilosaurus became even more elongated than Kellogg’s original drawing indicated. This resulted also in some problems, as the whole body was so strongly elongated that I could hardly work on it on the screen at once. Instead I had to work on sections and resize the view again and again to see how it works. One of the main references for its body shape was the ribcage, which shows us how thick its body was about. As Basilosaurus had an extraordinarily long abdomen, I made it somewhat more voluminous than the chest, similar to what we see in many modern cetaceans. To find the basic shape of the body was the most important thing to start until I went more into detail. I had to change my initial draft considerably when I re-checked the ribcage and forelimbs with the skeleton to get the position if the shoulder girdle in the correct way.
Head and mouth
Not surprisingly, the head took especially much time to illustrate, as it includes the most detailed features. I followed the same considerations as in my earlier cranial reconstruction of Dorudon. The line and corner of the mouth were particularly tricky, and it took a long time and many changes until I was finally happy with it. Many reconstructions of archaeocetes shows them with a very deep corner of the mouth, what gives them a quite reptilian appearance. But this animals were mammals, and had after all still the same basic masticatory musculature as us. This includes the masseter muscles, which were quite well developed in archaeocetes. We can see quite well the original position and shape of this muscles from the zygomatic arches. Furthermore there were some other masticatory and facial muscles as well, which affected the shape and position of the corner of the mouth.
If you have read my earlier posts about archaeocetes, you will know that I am a strong advocate against the common shrink-wrapped reconstructions of archaeocetes with skull-faced heads. I think there are several reasons why we see this type reconstructions so often. People look at those nasty teeth in the jaws and simply assume that they must have been well visible in the living animal. The vague similarity of the skull proportions with those of crocodylians likely contributes to this as well. For exactly this reason we see nearly every year cases in which the rotten remains of odontocetes are mistaken for „prehistoric“ reptilian sea monsters, like this orca carcass from New Zealand.
Another important point is that artists usually like drawing teeth, and depicting an animal in a badass way is clearly preferred over a „lame“ look in many cases. I was actually surprised how awesome and badass those formidable Basilosaurus teeth still look in the final reconstruction, even with the upper teeth fully covered by the upper lips. It looks now much lesser than the usual crocodile-faced depiction with bare upper teeth. I think most people don’t realize that a lipless Archaeocete could never close its mouth. Even when its jaws would be fully closed the teeth would be still fully visible and the cavity of the mouth constantly in contact with the surrounding water. We see such a condition only in some few highly specialized modern cetaceans like the Ganges river dolphin or the pygmy and dwarf sperm whales. But nearly all other odontocetes have upper lips and cheeks that cover their upper teeth (except of course oddballs like narwhals, but the still have lips). Even odontocetes with large teeth like orcas and false killer whales have fully lip-covered upper teeth. We can be also quite sure that the most archaic and still amphibious whale ancestors had lips as well – like other artiodactyls and mammals usually do. It would be really weird if archaeocetes reduced and even lost their upper lips and their descendants re-evolved them later again. It is also surely important to keep in mind that the general jaw shape dentition was not even that different between the early amphibious forms and the fully marine archaeocetes like Basilosaurus. So lips surely did work around this arrangement and shape of teeth.
What’s just uncertain is the flexibility of those lips and when archaeocetes had still more flexible and perhaps partially retractable lips similar to seals and when already stiff lips like most modern odontocetes. Perhaps the later forms in-between had a somewhat similar condition as we see in beluga whales. I tried to place it somewhere in between.
I also added some vibrissae on the top of the snout and upper lip, at top of the mandible and a few ones behind the nostrils. This are the areas where we still find vibrissae on modern baleen whales and in hippos as well. The whole topic of vibrissae in archaeocetes is quite complex, if you want to read more about it, take a look at this older article.
As a reminder you can see here the vibrissae of a North Atlantic right whale:
Take your fingers and touch your nose. Seriously, do it. Touch it on its back, at the base, the sides and the top. Move it. What do you feel?
will feel your Os nasale, the different cartilages on the sides and
on the tip, and you will also feel the tiny muscles which can use to
move the sides of your nose. We humans have somewhat weird looking
noses, but they have still the basic mammalian nose structure with a
lot of soft tissue over the skeletal opening of the nasal cavity. For
some reason comparably many reconstructions of archaeocetes simply
follow the outlines of the skull and only show some small openings
directly over the nasal cavity.
where are all the other parts of the nose? In odontocetes, we don’t
see much more than the blowhole as all the other parts of their
complex and asymmetrical nasal elements are hidden within the rounded
melons on the top of their cranium. The only exception is the sperm
whale which has a well visible lump of tissue around its blowhole
which is – unique in cetaceans – on the left side on the very top of
its giant spermaceti organ.
Baleen whales are a much better comparison with archaeocetes here. They lack the melons of odontocetes and have comparably little soft tissue on the top of their skulls. So the dorsal shape of the head is still quite close the the underlying skull – except for the fleshy hump which includes the two blowholes and the accompanying cartilages and muscles.
The neck of archaeocetes was still longer and much more flexible than those of modern whales. But this still does not mean that the head and torso were as strongly separated as we see it in some reconstructions. I made the neck and throat similar to those of a seal, with a slight indication where the neck ends and the thorax begins. In odontocetes with quite flexible necks like belugas, snubfin dolphins or Amazon river dolphins we see also comparable shapes, which differs from those if other whales with stiffer necks.
Some reconstructions of archaeocetes have quite weird looking skinny necks which strongly separate the head from the body, what´s again not likely at all.
The forelimbs of archaeocetes like Basilosaurus were still surprisingly underived compared with the flippers of modern whales and even the forelimbs of seals. They are comparably long and show neither really strong attachments for muscles nor elongations of the fingers. The reason is possibly the fact that archaeocetes had not that much use fore their forelimbs. The basal amphibious forms used their strong hind legs and tail to swim and maneuver underwater, similar to many modern amphibious mammals like otters, beavers, nutrias or even desmans and water opossums. In those animals we find often well developed webbing of the hindfeet, but much lesser on the fore feet.
We see the probably most derived adaptations to a marine habitat of a modern „walking“ mammal in the sea otter, which spends nearly its complete life in the water. This surprisingly large durophagous mustelid has only very short arms, whose main function is to find and collect invertebrate prey, and to crush open hard shells and sea urchins with stones. So I decided to reconstruct the forelimbs not as propper flippers but more like the comparably stumpy and leg-like arms of seacows. I also added a more speculative feature, some vestigial nails. I think so far there was no research to examine the proximal phalanges of archaeocetes to see if there is any indication for such nails. Their superficial structure of the bone could probly solve this mystery, to see if there was still any keratinous growth or not. Seal still have claws, which can be pretty big. Even the highly modified fluke-shaped hind limbs of phocids have short nails. In seacows, which are even fully aquatic we see small hoof-like nails in their forelimbs as well. So even if we don’t have direct evidence for vestigial nails in archaeocetes, we have also so far no direct evidence against it, and the idea really does not seem too far-stretched. So I gave my Basilosaurus seacow-styled protoflippers.
Tail and fluke
The original version of this Basilosaurus had still a deeper tail and a more conventional shape of its fluke. But I decided to reduce the tail somewhat and make it a bit slimmer, as the dorsal spines of the caudal vertebrae were still comparably short in Basilosaurus. As it also still lacked the caudal peduncle of modern cetaceans I tried to give the caudal fin a somewhat lesser derived shape. The flukes of archaeocetes are really tricky as we can’t reconstruct their shape from the underlying tail vertebrae as in ichthyosaurs and certain mosasaurs or metriorhynchids. Of course we can take a close look at the last caudal vertebrae und see if there’s something going on with them, for example if they are wider and more robust than the vertebrae before them. But this still doesn’t give us really much more information about the original shape of the tail or fluke. Archaeocetes started quite early to use their tails as primary propulsion and their forelegs were likely mainly for maneuverability whereas their hind legs were already fully useless for swimming.
indicates that a caudal fin was already present in the very early
fully marine archaeocetes. But how did it look like? It surely
started as a similarly dorso-ventraly flattened tail as those we see
in otters and there was also quite likely a stage with a primitive
spoon-shaped tail like those of manatees. But the problem is that
even with a totally complete line of evolutionary stages between the
tail vertebrae of the most basal archaeocetes up to those of modern
cetaceans with high dorsal spines, laterally compressed tails and a
caudal peduncle for the fluke, we would still don’t know how the
caudal fin really looked like.
To get a better understanding of this issue we can take a look at seacows. The manatees which mainly populate freshwater habitats in slow moving rivers or coastal areas (but don’t forget, they also crossed the Atlantic ocean anytime) have only a fleshy oval caudal fin, but it seems to work obviously well enough for them. Dugongs which are living in marine habitats are much more affected by turbulences, waves and similar things and have already a nearly whale-like fluke. They spread over large areas of the globe, over Africa, Asia and Australasia what indicates that they are quite seaworthy. In contrast to manatees they are also much more affected by predation, for example by tiger sharks. In the past they were quite likely also hunted by predatory cetaceans and in some areas possibly also by large marine crocodylians.
This are possibly the reasons why dugongs appear much more whale-like than manatees, as there was a much harder selection for strong swimming abilities than for manatees. Their caudal vertebrae also show elongated dorsal spines and some flattening of the most proximal vertebrae, but we would probably not expect such a well developed fluke from the bones alone. In direct comparison with those of whales it’s however still somewhat lesser derived. The tail is still comparably wide and the fluke itself comparably thick and fleshy.
This could give us some insights into the evolutionary history of whale flukes. I could imagine that there also was a strong selective pressure on the shape of archaeocetes as already little differences of its structure could have had comparably strong hydrodynamic effects. And we also shouldn’t forget that archaeocetes were unlike manatees or dugongs no herbivores but predators which hunted fast and agile prey. That’s why I tend to assume that highly derived oceanic predators like Basilosaurus already had comparably well developed flukes. So I reconstructed the caudal fin as a real fluke and not like manatee paddle, but still different from those of modern cetaceans. It’s still thicker, somewhat longer and more rounded. My very first version was still closer to the flukes of extant cetaceans but I wanted to keep the differences in vertebra shape more in mind and make this also somewhat more obvious in the external shape.
I also gave my Basilosaurus no dorsal fin. One reason for this was because I wanted to make a bit similar to right whale dolphins, little known odontocetes with a very thin and long body, which fully lack a dorsal fin. Another reason was to depict the Basilosaurus as different and more primitive compared with modern whales. However, we have to keep in mind that baleen whales and odontocetes diverged already very early in cetacean evolution, and both do have dorsal fins. So this means that those most basal ancestral baleen whales had either already a dorsal fin (perhaps a very primitive one at least) or that dorsal fins evolved later parallely in both lineages. That´s some food for thought.
The coloration of prehistoric animals contains for obvious reasons an especially big amount of speculation, unless we have cave paintings or exceptionally well preserved fossils which can give us some direct evidence for the patterns and colors. In the case of Basilosaurus we have at least some extant relatives, but they can give us still only a vague hint about the colors and patterns of prehistoric whales. I wanted to avoid just another Basilosaurus with the colorations of the Walking with Prehistoric Beasts Basilosaurus. It really doesn’t look that bad and it’s not implausible but I just wanted something different. I’ve discussed the coloration of large marine animals for the paint job of the Meyerasaurus by my friends of kamyk.pl for the museum at Lodz at length here. For the Basilosaurus I also made a first version with a similar color scheme that was somewhat reminiscent to those of a leopard seal. Then I tried a more homogeneous and darker main color which was inspired by false killer whales and long-fin pilot whales, which have also quite elongated bodies. I also made no classical counter-shading with a generally lighter underside. This is more a trend than a rule and a large number of marine tetrapods, especially seals but also a lot of whales, show no real counter-shading at all. Instead I made the area of the throat visually distinctive with a white patch, something we also find in many different modern whales. Because of the incredibly elongated body of Basilosaurus I made also a small white patch in the area of the small hindlimbs. I could imagine that such an eyecatcher of the genital area could make sense in an animal which had possibly really some obstacles to find the right position during mating. We find also similar white eyecatchers (or, as I call them, cetacean arseantlers) in a lot of very different cetaceans, from right whales to sperm whales and various other odontocetes. This brings us to the next point.
One of the great things about digital painting is that you can recombine your work again and again. So I made just another Basilosaurus from the first one, what gave me also some more good chances to depict some other aspects. At first I scaled it down to show the sexual size dimorphism. Male Basilosaurs were about 20% longer than females, based on studies of their bones. The second Basilosaurus was also a good opportunity to depict it with a closed mouth. Its mouth is now fully shut and the lips make the teeth no more visible. Remember this couldn’t work at all without upper lips, the teeth would be exposed all the time.
To make the two somewhat more individual I changed the position of the forelimbs of the male to indicate a certain approaching position towards the female. The male has also a slightly lighter coloration, something we also see in older males of many cetaceans like sperm whales or bottlenose whales. He received various scars as well to indicate some intraspecific fights with other males. This is also a quite common thing in various odontocetes from sperm whales to many beaked whales and a lot of dolphins. Last but not least he got a genital organ as well. In fact this was the very first time that I have ever depicted something like this. But prehistoric animals were not always just fighting, hunting and eating and even a gigantic apex predator like Basilosaurus had a social life and sexual interaction. One could even say that next to everything an animal does, no matter if it’s hunting, eating or fighting, has the main purpose to ensure that it can successfully reproduce during its life. So here we go, Basilosaurs having fun.
You shouldn’t underestimate the background fauna. Sometimes it can be somewhat annoying and time-consuming to paint it, but if you have already spent a lot of time on your main subject you can also give it some nice substitutes. You should see the background fauna as a chance and not as a time waster. It gives you a chance to depict some interesting and possibly hardly ever shown species with comparably little effort (unlike a full life-depiction of those animals being in the focus themselves). For this reason you should also avoid totally random stereotypes but really take some time to make a correct depiction. Fish are quite typical elements for background or „prey“ fauna but unless you make a swarm of really tiny and individually unrecognizable fish you should really try to make a realistic depiction. If you are not really familiar with the animal you want to depict, you will very, very easily make errors. I write this because that’s exactly what happened when I started with some unspecified random fish. So I was searching for something better and decided to make a swarm of mackerels. They have a very good fossil record with great specimens from the Eocene which were already very similar to the modern forms. They would also fit within a scenery in the open water and their familiar appearance gives also some more scale for the size of the Basilosaurus. Furthermore I could depict a visually more interesting fish than just one with silver-white colors.
are also some recycled nautiluses in the background to make the fauna
a bit more diverse and to add something that appears somewhat
ancient and primordial.
I spent also a considerable amount of time on a Dorudon which was originally only planed as a simple background illustration but at the end it became a similarly detailed reconstruction as the Basilosaurus itself. At first I wanted to depict Basilosaurus hunting a juvenile Dorudon, but then I wanted to depict it next to an adult specimen. The skull length of Basilosaurus and Dorudon is surprisingly similar, despite the very different total lengths. Those of Dorudon has however more elongated jaws and is lesser massive than those of Basilosaurus. But this was still a pretty big animal, about as large as a false killer whale, and with really large jaws.
The Dorudon in detail:
What I really want to emphasize here is that I don´t think this particular reconstruciton is the one and only possible. That´s why I wrote where things were more speculative but also why I made it the way I did. Some traits like the upper lips and the vibrissae (perhaps lesser pronounced, but perhaps even more) were nearly certainly present in archaeocetes, whereas other traits like the shape of flippers and fluke or the presence of a dorsal fin are much more of an issue.
Gingerich, P. D., B. H. Smith, and E. L. Simons. 1990. Hind limbs of Eocene Basilosaurus isis: evidence of feet in whales. Science, 249: 154-157.
Zalmout, Iyad S. 2000. Priabonian Basilosaurus isis (Cetacea) from the Wadi Esh-Shallala formation: First Marine Mammal from the Eocene of Jordan. Journal of Vertebrate Paleontology 20(1):201–204.