The Huchen – Salmonid King of the Danube

If you are interested in unusual freshwater fish, you have possibly heard about the taimen (Hucho taimen), a very large predatory salmonid which lives in remote parts of Mongolia, Russia and some other areas of North Asia. This species was already covered in an episode of River Monsters with Jeremy Wades and also in the National Geographic Monster Fish series with Zeb Hogan. The habitat in exotic and remote areas outside the western world clearly increased the nimbus of the taimen as an elusive monsterfish. It is much lesser known that the taimen has a close and nearly equally impressive relative which lives even right in the centre of Europe.

Adult huchen (Hucho hucho) at the river Drina between Bosnia and Serbia. Photo from Wikipedia

The name of this fish is Huchen (Hucho hucho), sometimes also still called Donaulachs (Danube salmon) in German. Despite this old name, the huchen is no real salmon. The genus Hucho represents together with the related Brachymystax genus a unique clade within the Salmoninae subfamily of Salmo, Oncorhynchus,  Salvelinus, Parahucho and Salvethymus that includes the very diverse and numerous trouts, salmons and chars. For such a big predatory coldwater fish it is surprisingly colourful, with copper-red flanks at the back-half of its body. It has also an unusually large adipose fin.

Juvenile Huchen of about 40 cm, Wilhelma Zoo, Stuttgart. It lives with several other huchen and some brown trouts in a big paludarium.

The huchen lives in fast-streaming water, and has a very elongated and spindle- shaped body. In cross-section, most of its body is nearly round, unlike those of trouts, salmons or chars, which have an oval cross-section. The head of the huchen is comparably flat with a very wide mouth, and its jaws and tongue are equipped with well developed teeth. In contrast to many trouts, salmons and chars, male huchen never grow a hooked mandible during the mating season.

Mouth of a taxidermy huchen, Haus der Natur, Salzburg.

It is a voracious predator which feeds on other river fishes like the common nase. It is also well known to attack tetrapods on occasion. Small rodents and small birds like kingfishers or dippers were already found in the stomaches of huchen. For this reason, baits which imitate swimming rodents are quite popular huchen lures. In earlier times lampreys were also an important component of their diet, but those primitive vertebrates have become quite rare today. There is even a traditional bait called the Huchenzopf which imitates a group of small lampreys. Old models were usually made from a lead weight and pieces of leather or rubber tubes, today the are usually made with soft rubber.

The original range of the huchen is restricted to the fast-streaming and clean tributaries within the basin of the river Danube, as well as a few lakes like Lake Plav at Montenegro. There were also unsuccesful attempts to introduce it to rivers in France, the Netherlands and Great Britain. Surprisingly such artificial stocking was however successful in some rivers at Spain and Morocco, but those populations are not sustainable. According to one single source I could find, specimens from the Bulgarian huchen populations occasionally swim into the coastal waters of the Black Sea. But I could sadly find no further information about this. It would be extremely interesting to know if this is really true, and if huchen show also similarly strong morphological changes in colour and body shapes as sea-dwelling brown trouts, rainbow trouts or chars.

The huchen also lives and even breeds in the river Isar, even right within the city of Munich. That´s really an unusually non-exotic home territory for such an enormous and generally little known near-megafish. Just keep this in mind should you ever go visiting Munich. You´re walking there alongside a river inhabited by the second largest non-anadromous salmonid of the world.

River Isar at Munich

The huchen is usually the largest predatory fish of the fast-streaming and comparably cold waters where it lives. It reaches often lengths of over a meter, and record specimens can reach at least lengths of 1,30 –1,44 m and weights of around 30-40 kg. You can see some photos of exceptionally big specimens here. Of course there are as usual stories of bigger ones, but as big-fish-stories are notoriously untrue and the largest claimed sizes for fishes are quite often unconfirmed anecdotes and hardly trustworthy, I prefer to stay on those lengths for which we can find confirmed data. But even then, the huchen is a huge fish. Among the non-anadromous fish of middle Europe, only the wels catfish grows considerably bigger. It also exceeds the largest ecotypes of lake dwelling brown trouts (Salmo trutta) and even the official angling record specimens of the northern pike (Esox lucius). Only the very largest Atlantic salmons (Salmo salar) reach similar record lengths and even higher weights, like the historical monster specimen covered some time ago. But this salmonid is anadromous and gains its size in the sea. For a pure freshwater fish which lives in comparably shallow and cold streams, the huchen is a true giant.

Here is a Huchen of 130 cm lenght and a weight of 25 kg, 125 g which had a 79 cm girth. Caught in 1961 in the river Loisach near Eurasburg. Photo taken at Deutsches Jagd-und Fischereimueum (museum of hunting and fishery) Munich.

 

Sadly – and not really surprisingly- the huchen isn’t doing well. As many other fishes which need clean and oxygen- rich streaming water, it suffered considerably from pollution and changes of the original shape of the streams. One of the most serious problems is the loss of most of its spawning grounds. The huchen needs clean gravel in fast streaming and clean water for its spawn. But such areas have significantly decreased in number. Another problem is the decrease of prey fish for the young huchen, like the common nase (Chondrostoma nasus), a cyprinid which populates the same streams as the huchen. Its fry is among the most important prey items for small huchen.

A super-bulky and testosterone-bloated male brown trout which was rubbing itself for a considerable time on the back of a subadult Huchen. Photo from Wilhelma Zoo, Stuttgart

Today the huchen can only survive in many streams due to artificial stocking. It is a good thing that this works at all, and that a few adult specimens can produce vast numbers of eggs which can be used to breed thousands of young fishes. But the other side of the medal is a massive reduction of genetic diversity in those fish. That is one reason why it is so important to make sure that specimens of endangered species should be able to survive and reproduce in the wild.

Veröffentlicht unter Blogposts in English, Fische, Megafische | 2 Kommentare

When Giant Tunas roamed the Baltic Sea

In terms of zoological diversity, the Baltic Sea is probably the most boring sea of the world. It has the lowest salinity of all seas and it is only connected with one other sea, the North Sea. As a result of this it has only a very low number of native species, and those are also not particularly spectacular compared with those of the North Sea or the northern Atlantic.

What’s especially noteworthy is the nearly total absence of any bigger animals there. The largest marine mammals which are really native there are grey seals, harbor seals and harbor porpoises. The grey seal and thr harbor seal were already nearly fully extinct in the late 20th century and today there are only a few hundred specimens left. The harbor porpoise is also extremely rare and among the smallest cetaceans of the world. So even the mammalian marine megafauna is not exactly impressive to say it at least. As a result of the low salinity no sharks are native in the waters of the Baltic Sea. The biggest commonly occuring fish you can hope to see are only Atlantic salmons, sea trouts and cods. All of them rarely grow bigger than a meter as even the cods of the Baltic Sea stay much smaller than their cousins in the Atlantic Ocean and North Sea. Of course there are occasionally cases of vagrant specimens of bigger fish which usually don’t occur there, or even out-of-place cetaceans like rorquals or sperm whales. But this are rare exceptions and they could not even survive for a long time in the Baltic Sea, as they could not find suitable prey in this shallow sea. As you see, aquatic megafauna is next to absent there.

This makes it even more surprising that there actually were gigantic fishes in the Baltic Sea until just a few decades ago. Giant blue fin tunas were common denizens of the Baltic Sea. This predators are among the largest teleost fishes of the world, with record specimens of more than 650 kg and lengths of more than 3,5 m. The ones caught in the Baltic Sea were not that gigantic, but still dwarfed every other fish around, since the European sturgeon which also once populated this waters has become practically extinct in the early 20th century. Some of the tunas living off Denmark grew to massive sizes, like this one which was caught around 1880 whose skeleton is now on display at the zoological museum of Copenhagen.

Skeleton of Atlantic bluefin tuna from around 1880, Zoological Museum Copenhagen

Sometimes tunas of more than 300 kg were caught, and the record was even a massive specimen of 372 kg.

Here is skull of a big tuna caught in 1962 at Howachter Buch, Germany, now on exhibit at the zoological museum of Kiel.

Bluefin tuna skull, Zoological Museum Kiel

I added a pocket rule of 50 cm to give you a better idea of the size. Here is another photo which shows the skull with the reconstructed outline of the whole fish.

Bluefin tuna skull, Zoological Museum Kiel

Bluefin tunas were regularly caught by fishermen in Danish and even German waters. They were so frequently caught that a factory for canned tuna was built in Skagen in 1929. Sport fishermen came even from Great Britain to Denmark for big game fishing. But the whole business ended in the 1960ies when the tunas disappeared from the Baltic sea. The reason was overfishing, not only in Denmark but also in other parts of the world like in the spawning grounds in the Mediterranean Sea and the Atlantic ocean where the bluefin tuna has its nursery ground.

Today there is not much that reminds on this giants anymore. At Odden Havn, a small fishing port at the north coast of Sjaelland, you can still find old photos from the time of commercial tuna fishing, which seem nearly surreal today. Here is a historic photo of fishermen with tunas from Odden Havn, Denmark.

This port was one of the former centers of tuna angling and fishing. Even today there is still a tavern name tuna. Many years ago, there was still a large taxidermy head and caudal fin of a trophy tuna at the „Tunen“-restaurant of Odden Havn. I think it is now on exhibit at the tuna fishing museum of Odden Havn, which opened just a few years ago. Sadly it was every time closed when I was there, even at days when it should have been open, so I don’t have any photos from the interior.

The tuna museum at Odden Havn, Sjaeland.

The old trophies, skeletal remains and black and white photos seems to be the last remnants of a bygone era. But in recent years, the first blue fin tunas came back to the Baltic Sea. In September 2017 a swarm of tunas wad sighted off and subsequently a project was started to tag some of them. One of them was caught with hook and line, a huge specimen of 2,51 m length and an estimated weight of 285 kg. This was the largest fish which had been caught in this waters since half a century. After it was tagged, it was released again. Of course the tunas are now strictly prohibited there and catching them is only allowed for scientific research.

The „Tunen“ restaurant at Odden Havn.

It will likely take many decades until tunas are again regularly found in the Baltic Sea, but their eventual reappearance seems to be a good start at least. But it is also a reminder that tunas are not just big tasty fish but endangered marine wildlife which are already exterminated in much if their original range. They are marine megafauna like cetaceans, seals or sharks, but they still don’t get the same sympathies. Even people who are outraged about the slaughter of whales for „scientific research“ or the killing of sharks for their tasteless fins will often still happily and regularly buy and consume tuna. I strictly reduced my tuna consumption already many years ago and it would really help if more people would appreciate those fish not just for their culinary qualities but see them instead as endangered wildlife and giant marine predators which are close to the top of the food chain.

To conclude, I really have to apologize for my seemingly harsh words towards the Baltic Sea at the beginning of the blog. I absolutely love the Baltic Sea, it is by far the sea with which I am most familiar with, and I it has its very own loveliness and beauty.

Coast of Ordruo Naes, Denmark

Another photo:

Coast of Korshage, Denmark

And one more:

Coast of Klint, Denmark

Veröffentlicht unter ausgerottete Arten, Blogposts in English, Fische, Megafauna, Megafische | 2 Kommentare

Zoological treasures in Archeological, Historical and Ethnological Museums

This blog is devoted to the wonders and marvels of the animal kingdom and natural history. Many of the photos in my articles were taken in zoological or paleontological museums. But you can also often find a lot of really interesting zoology-related artifacts in other museums as well. I have a longstanding interest in archeology, history and ethnology, and for that reason I visited countless museums about those fields over the years.
I have seen there innumerable and sometimes really surprising exhibits which can be also of great value for people interested in zoology. Not everyone can spend several hours analyzing the construction of ancient arms and armor or the carving techniques of old wooden spoons as I sometimes do. But even if you are not really an avid fan of archeological, historical or ethnological museums but interested in animals (I suppose you are, otherwise you would not read my blog), I can encourage you to take a closer look at those locations. I think I can not emphasize enough the potential of such collections, and sometimes you can even find amazing and fully unexpected zoological treasures that you will rarely find even in natural history museums.

The vestigal narwhal tusk featured recently is such a case. The Inuit tools made from the teeth of Greenland sharks were the very relics of Somniosus I have seen anywhere. Another example would be the mandible of a pygmy sperm whale in the Oceania exhibition of the ethnological museum at Berlin (I already wrote about it several years ago here).

Pygmy sperm whale (Kogia breviceps) mandible, Ethnological Museum Berlin

The mandible was sadly labeled as the jaw of a dolphin. I tried to contact the museum to inform them about the true identity and rarity of this mandible, which belongs to a species which is really rare even in the collections and archives of museums with many cetacean specimens. Sadly I received no answer.

This leads to another thing. This is really not meant to discredit the scientists, curators or the staff of those museums, but over the years I have seen a whole lot of erroneously labeled exhibits in archeological, historical and ethnological exhibitions. For this reason it can be really beneficial if people with a more profound knowledge of zoology take a closer look at them. Of course no one likes a smartass (ans yes, I am fully aware of my strong tendency to be one), but museums have an educational purpose and labels should be corrected if they are erroneous. At the end, that’s also beneficial for those museum and their visitors, in particular if a „boring“ object becomes suddenly much more interesting.
This is even more important if erroneous identifications lead to erroneous interpretations, what’s especially problematic in the archeological context. I hope to feature such a case in the near future.

But enough with the criticism, in the vast majority of cases the identifications of animals in such museums are correct, an you can learn a lot from them.
Real physical remains of animals are of course especially interesting, the more so if they belong to unusual or now extinct species. I have seen many subfossil aurochs skulls and horn cores, and even some full skeletons, and a great number of them in archeological museums. This included even a particularly spectacular (perhaps even the most spectacular) specimen which I will spare for a future blog post. So if you are a fan of Bos primigenius, you can likely expand your specimen count in archeological museums to a substantial degree.

Aurochs (Bos primigenius) horn cores (on the top) in the archeological museum Strasbourg. Did you notice the warthog model?

But even the skeletal relics of lesser uncommon animals are always worth to take a closer look at them, no matter if they are wild or domestic animals. Sometimes you will also see bones of animals which are now extinct in the area where their relics were found, like Central European mooses. Some animals which greatly suffered from trophy hunting over many centuries have also often decreased in size. For that reason you can often find especially massive deer antlers or huge wild boar tusks which come from archeological excavations or which are from historical hunting collections.

A huge neolithic wild boar skull with enormous tusks from the National Museum of Denmark, Copenhagen

Ethnological collections are sometimes real treasure chests, as they often include really exotic animal remains. Anatomy, behavior and ecology of animals are all fascinating things, but I think the interaction of animals with humans are always important to look at as well. The cultural or economic role or value of animals, the way in which they were hunted or caught or what was made from them. This are all really interesting topics of themselves, but they often get not that much attention in zoological museums.

Necklace made from hornbill beaks, likely from New Guinea. How often can you take such a good look at the inside of their mandibles? Photo taken at the Ethnological Museum Munich

You are sometimes really surprised by the weird hunting methods invented for certain species or the curios use of certain animal parts. Sometimes such processed body parts can give you even insights into anatomy that you will usually not see at a taxidermy specimen or a mounted skeleton.

A very nice collection of Crocodylus porosus skulls and boar skulls. Ethnological Museum Munich

In exhibitions about Oceania you will often find especially many artifacts made from animals.

Necklace made from sperm whale teeth. This gives you a pretty good idea about the variation in shape of sperm whale teeth. The big blunt tooth is quite interesting, as it shows severe abrasion. Photo taken at the Ethnological Museum Berlin

Native American artifacts can be also very interesting, for example if they give you a chance to take a close look at bison skulls.

Bison skull with painted ornaments, Ethnological museum Berlin

But not just physical remains can be valuable objects of interest, but artistic animal depictions as well. In some cases they can tell you things about now extinct animals that you can’t see if you just look at their bare bones. Colours, patterns, even certain typical kinds of behavior and interaction with other animals and humans can be found in ancient art or historical depictions.

Mammoth ivory figurine of a cave lion from Vogelherd Cave at Schloss Hohentübingen. Could the pattern carved on the body indicate that some cave lions had more or less pronounced spots?

One especially worthy field to discover in archeological museums are old forms of domestic animals. You can for example look which unusual traits typical for domestication were already present. You can take a look at ear shape, length or structure of the fur, the pattern and colour of the hides or other traits you can not judge from skeletal remains alone. Many old breeds of domestic animals became fully extinct, others changed so much that they bear no more much similarities with their ancestral forms.

A greek bronze helmet from 300-400 BC. The engraving of the bull is just wonderful and incredibly naturalistic. It reminds a lot on a Spanish fighting bull.

A small roman bronze figurine of a domestic bull with strongly developed dewlap.

Roman bronze bull, Landesmuseum Stuttgart

Terracota model of a South American dog breed. This small, short-legged dogs had strongly wrinkled skin and were bred for their meat.

Ethnological museum Berlin

Domestic dogs were already quite diverse in antiquity, and very different breeds already existed millenia ago.

A greyhound-like breed of dog on a Greek amphore, ca 440 BC. Photo taken at Landesmuseum Stuttgart

You can for example see typical traits of domestication in some of those old breeds, like floppy ears of a curled tail.

Dog with floppy ears and curled tail on Greek amphore, 480-470 BC, Antikensamlung Berlin

A very nice life-sized sculpture of a hunting dog from ancient Greek. This is in fact a cast from gypsum and not the original.

Greek hunting dog, Schloss Hohentübingen

Of course you always have to keep in mind that there can be a lot of artistic freedom in such old depictions. Sometimes more, sometimes lesser. But to get a better idea and understanding of that, it is important to study the various art styles of different cultures. In some cases you will be really surprised by the level of accuracy of those ancient artists. Some of the ancient Egyptian paintings and reliefs are so naturalistic that it is easy to identify even a lot of animals to species level.
On occasion you will even see quite unexpected scenes of human-animal interaction, like apparent attempts to tame wild animals. It is also sometimes really surprising to see the degree of human translocation of animals which happened already hundreds or thousands of years ago.

How to transport an elephant on a ship, Roman mosaik from Veji, 300-400 AD, Landesmuseum Karlsruhe

The depicted elephant was most likely the now extinct small North African subspecies Loxodonta africana pharaohensis.

You can also sometimes see unusual curiosities from historical collections, like anomalous antlers, horns or tusks, or bezoars which were thought to have healing powers, similar to the inevitable narwhal tusks. In other cases there are very early examples of exotic animals or animal parts which found their ways into cabinets of curiosities or early zoological collections. You will find such collections much more often in historical than zoological museums, and they can give you interesting insights into the history of modern zoology.

Bird of paradise in historic cabinet of curiosities, Landesmuseum Karlsruhe

Here you can also see a wonderful mug made from narwhal tusk. You can see that was from the base of the tusk, as the surface is unabraded and highly textured.

Narwhal tusk mug, Museum für Kunst und Gewerbe, Hamburg

An original copy of Conrad Gessner´s (1516-1565) Historia animalium, one of the very first zoological books of the world. The same exhibition also had an original print of Dürer´s Rhinoceros.

Historia animalium by Conrad Gessner, photo taken at a special exhibition at the Museum für Kunst und Gewerbe, Hamburg

I hope I could show you with this blogpost why it can be always worthy to think outside the box, and to visit as many museums as you can, even if they are not always restricted to natural history alone.

Veröffentlicht unter Archeology, ausgerottete Arten, Ethnology, Säugetiere, Wale | 2 Kommentare

A moustache for the elephant bird – had Aepyornis facial bristles?

A recent study in which digital endocasts of elephant bird skulls from Madagascar were examined, has shown that those gigantic flightless birds had extremely reduced optical lobes. At the same time, their olfactory lobes were very large, what indicates that Aepyornithids were likely noctural and used their keen sense of smell to find their food.

This reminds a lot on another kind of weird flightless birds of our modern time, the kiwis from New Zealand. Kiwis have very poor eyesight and find their food items – which are mainly earthworms, insect larvea and other inverbetrates – by probing the ground with their highly tactile beaks. One novel trait of kiwis are their nostrils, which are extremely close to the tip of the bill, what allows them to literally smell underground.

The foraging habits of elephant birds were surely quite different, as they were mainly herbivorous. This whole study is really fascinating, and I recommand you to read it yourself, as I don´t even want to go too much into its details. The motivation why I write this blogpost has another reason. If elephant birds like the studied species of Aepyornis maximus and Aepyornis hildebrandti had very poor eyesight and were possibly noctural, is it really that likely that they just relied on their sense of smell in the darkness?

I don´t really think so, nor do I really believe that they were blind as many recent headlines boldly claim. Reduced optical lobes do not mean that an animal is fully blind, nor would it make really sense. Even animals which mainly rely on other senses like smell or echolocation, for example shrews or bats, can still see, even if this is not their main sense. Kiwis have also a reduced optical sense, yet they aren´t blind at all. A strong sense of smell alone also does not help a lot for orientation in a forest or scrubland, especially if you´re a giant bird of 3 m height. The orbits of elephant birds also do not indicate a reduction of eyeball size as seen in kiwis, so the claim that those birds were really blind seems quite dubious to say it at least. Cassowaries have also a keen sense of smell and are mainly noctural, but show no reduction of their vision.

But even if elephant birds really had an extremely strong sense of smell and a really weak (but not absent) vision, is it possible that they used also another sense for orientation or to pick up food items like fruits? If we look at modern kiwis, we see some extremely long whisker-like feathers near the base of their beaks. They act like the vibrissae of mammals as sensory organs, what´s surely especially important if they have their heads within leaf litter, vegetation of very close to the ground, and to avoid injuries from branches, thorns or stones. So is it possible that elephant birds had similar sensory bristles? If they really had similarly weak vision as kiwis, this seems really quite likely. But I really have to emphasize that this is just speculative so far. A close examination of the invervation of those feathery bristles and their connection with the bigger cranial nerves and corresponding brain areas in kiwis could surely help to see if this structures could have been present in elephant birds as well.

I made this illustration of an Aepyornis maximus with some bristles at the base of the upper beak to give you an idea how this could have looked like. The silhouette depiction made it possible to create this within a comparably short time and to avoid the depiction of the eyes at the same time. Compared with those of kiwis, the bristles are even comparably short and subtly depicted.

Aepyornis maximus with sensory bristles by Markus Bühler

For comparison the head of a taxidermy kiwi specimen which shows the really long and space-consuming bristles which forms some kind of sensory shield around the facial area.

Taxidermy kiwi specimen, photo taken at Staatliches Museum für Naturkunde Karlsruhe

If elephant birds really had bristles similar to those on my illustration, or even more extensive as those we find in kiwis, this already highly unusual birds would have been even much more bizarre than we already thought. This makes it even more tragical that we missed those enigmatic creatures just for a few centuries, and much of their anatomy and biology will still remain a mystery forever.

It is also interesting to take a look at some modern large flightless birds. Rheas have also bristle-like feathers around the corners of their mouths, the base of the beak and around the eyes.

Rhea head, photo by Markus Bühler

We see a similar condition in emus as well. Even if this could have an additional function to protect the eyes and ear openings from dust and dirt, it seems also likely that they could have a sensory function to avoid injuries of the facial area when they pick for food.

Emu at Battersea Park Children’s Zoo, Photo from Wikipedia

Ostriches have also very long fine feathers, which were especially well developed at the upper base of their beaks. They don´t show the bristle-like nature as those of kiwis, which differ significiantly from the surrounding plumage.

Ostrich head, photo from Wikipedia

Now the weird thing is that cassowaries fully lack such bristle-like feathers around their mouth or beaks, and it is hard to say why. It is still really strange, as cassowaries are among all those modern flightless birds here the ones which live in the most densely vegetated habitats. Perhaps their strong ceratinous frontal shields prevents them from most injuries. If you take a close look at this photo, you will also notivce the position of the nostrils, which are pretty close to the tip of the beak.

Casuarius bennetti, Avilon Zoo, Rodriguez. Photo from Wikipedia

So again we see that soft tissue reconstructions from animals only known from their bones remain a challenge with a lot of unsolved questions.

References used for this article:

Christopher R. Torres, Julia A. Clarke. Nocturnal giants: evolution of the sensory ecology in elephant birds and other palaeognaths inferred from digital brain reconstructions. Proceedings of the Royal Society B: Biological Sciences, 2018; 285 (1890): 20181540 DOI: 10.1098/rspb.2018.1540

Cunningham SJ, Corfield JR, Iwaniuk AN, Castro I, Alley MR, et al. (2013) The Anatomy of the bill Tip of Kiwi and Associated Somatosensory Regions of the Brain: Comparisons with Shorebirds. PLOS ONE 8(11): e80036. https://doi.org/10.1371/journal.pone.0080036

Veröffentlicht unter ausgerottete Arten, Megafauna, Vögel | Hinterlasse einen Kommentar

The amazing Nautilid Diversity of the Post-Cretaceous Seas

The modern nautilus is usually seen as some sort of archaic relic from an ancient era, unaffected by the changes of time. They are often considered as an anachronistic remnant of an age when the seas were populated by marine saurians and ammonites. But this animals are much more diverse than most people think. Even long after the extinction of the ammonites, which had been a dominating element of the oceans over hundreds of millions of years, the nautilus family still thrived. There is also not just one modern nautilus species. Besides the well known Nautilus pompilius, there are – depending on morphological or genetic differences – from two to six other species.

This includes Allonautilus, a highly elusive cephalopod genus which had been known for a long time solely from floating shells. There are two known species, A. perforatus and A. scrobiculatus. It was already assumed to have gone extinct, until living specimens of A. scrobiculatus were found in 2015. Allonautilus differs significantly in the shape of its shell from Nautilus, but even more so in other traits. The hood or lid on the top of the head which is also used to close the opening of the shell is dark purple in color. It is covered with more and denser tubercles than the lid of Nautilus and is also very different in overall shape.

Allonautilus is also called the fuzzy nautilus, because its shell is covered by a yellowish fine fuzz, whose function is still unknown.

Nautilus and Allonautilus scrobiculatus, picture from Wikipedia

Interestingly it seems that Nautilus and Allonautilus are paraphyletic and that Allonautilus evolved from Nautilus. This is also important considering the age of Nautilus, which is apparently also not older than around 60 million years. A. perforatus shows also a unique ribbing of the shell, which is not found in any other extant Nautilus species. How the rest of the animal looks in life is still unknown.

Allonautilus perforatus shell with distinctive ribbing, photo from Wikipedia

As primordial as they may appear today, the Nautilida kept on evolving within the last 65 million years, and the modern species are no unchanged living fossils, but the products of ongoing evolution.

I want to show you now some examples of post-cretaceous Nautilida fossils, which significantly differ from our modern species. I start with Nautilus imperialis, which lived in the early Eocene. It was much larger than its modern relatives and reached nearly the diameter of a football. It was also quite compact in overall shape. I tried to made a life reconstruction based on some fossil specimens from the Naturkunde- und Mammut-Museum Siegsdorf. This was one of my very first tries with digital painting and only done with a mouse instead of a graphic tablet, so there is still a lot that could be done better. I tried to give it a recognizably different appearance, with a different pattern and color scheme of the shell and soft body, and a different spape of the lid. Of course this all is still fully speculative. Cephalopods are surprisingly conservative in color, and we find various shades of reddish purple to brown, often coupled with white in most species, from squids to cuttlefish, octopi, vampiroteuthids and nautiluses. On the other hand we find such weird things like yellow fuzz in Allonautilus scrobiculatus nobody had ever expected…

So I made it still not too different from N. pompilius, with a more extensive red area of the shell, lesser distinctive stripes and a different shape of the lid with small but numerous tubercles.

To give it a bit more life I tried to add some background scenery, four additional nautilus specimens and an archaic whale.

Nautilus imperialis reconstruction © Markus Bühler

I used two fossils of N. imperialis fossils from the museum at Siegsdorf as references. They are 50 million years old and admittedly I don’t know if the derived fully aquatic archaeocete is not already somewhat anachronistic, as it would be around 10 million years younger. But I could not find more references when N. imperialis or very similar forms became finally extinct. There is even some speculation that the rise of marine archaeocetes was the driving force behind the reduction of nautilus diversity.

Nautilus imperialis, Naturkunde- und Mammut-Museum Siegsdorf

Another fossil of N. imperialis, which shows quite well the very compact shape of the shell:

Nautilus imperialis, Naturkunde- und Mammut-Museum Siegsdorf

Here you see the fossil together with some modern Nautilus shells for comparison:

Nautilus imperialis, Naturkunde- und Mammut-Museum Siegsdorf

Many thanks here also to Joschua Knüppe who gave me many highly helpful tips for the use and effects of colors and light underwater and the work with digital graphic programs. At the end this project which was only an intention to make a life reconstruction of N. imperialis for this blogpost at first, turned into something on which I worked several hours a day over a whole week. I am still not happy with a lot of details, but anytime I decided to make a break.

Here are some more fossil nautilus shells from the same museum:

Arturia lingulata, Naturkunde- und Mammut-Museum Siegsdorf

.

Nautilus umbilicaris and Nautilus imperialis, Naturkunde- und Mammut-Museum Siegsdorf

This Arturia shells have highly ornamented shells, very unlike the Nautilus shells we are used to see today.

Arturia sp. and Arturia lingulata, Naturkunde- und Mammut-Museum Siegsdorf

With this blogspot I also hope to evoke some more general interest in the lesser known post cretaceous marine fauna which did not just consist of Megalodon and some archaic whales.

This is also meant as a hint to all those readers who create paleoart. If you make life reconstructions of archaic whales or other postcretaceous marine mammals, you can give your art much more life and informative depth by adding not just some random fish or invertebrates, but real contemporary fauna. Animals like those big or elaborate nautilus species are practically absent in paleoart. Perhaps this blogpost will inspire some of the many people who are much more skilled artists than myself to draw or paint anytime their own reconstructions of postcretaceous nautiluses, either as a main sujet or accompanying other marine fauna.

Random archaeocete with a nautilus from the background of the bigger screen, before it was covered by shadows and light effects. Sadly the vibrissae on its lips are hardly visible here.

 

Veröffentlicht unter Cephalopoden, Paläontologie, Populäre Irrtümer | Hinterlasse einen Kommentar

The Narwhal´s lesser Tusk

I have seen a whole lot of narwhal tusks in museums, many skulls of narwhals (Monodon monoceros), some fully mounted narwhal skeletons and even several specimens with  double tusks. But so far I have never ever seen the vestigal right tusk of a narwhal somewhere on exhibit. Male narwhals have always two tusks, but in general, only the left one is noticable and protrudes out of the upper lip. The right tusks however usually remains embedded within the maxillary bone and normally never erupts. This tiny tusks are much smaller than the erupted tusks, and you can only see them if they are extracted out of the skull, or if the bone of a skull is already damaged. So far the very only vestigal narwhal tusk I had seen was one which was still embedded into a the broken bone of a skull I have seen at the archive of the Zoological Museum at Copenhagen. But much of it was still hidden under bone.

So I was really highly astonished when I recently discovered such a specimen which was fully bare of bone. But it was not in a Zoological museum, but in the exhibtion of the Landesmuseum Württemberg at Stuttgart, a historical museum about archeology and the history of the territory of Württemberg. It includes a historic cabinet of art and curiosities, the Kunstkammer („art chamber“), which dates back to the late 16th century. The tusk is a loan from the Natural History Museum at Stuttgart, probably as some sort of surrogate for a big narwhal tusk, which would not have fitted into the showcase. It was also only labeled as „narwhal tusk“, without any additional information about its unusual nature, but the old-fashioned hand-written labels indicates that it is  not of modern origin.

Vestigal right narwhal tusk, Kunstkammer Landesmuseum Württemberg, Stuttgart

As you can see, the shape differs a lot from those of the iconic „unicorn“ tusks. It fully lacks the spiraling, which is so typical for the erupted tusks. But this one still seems to have some parallel grooves. It is also not fully straight, because it is not twisted. The erupted tusks are often not completely straight, but form a more or less pronounced corkskrew-shape. But they always follow a nearly perfect straight line around their centre, as the spiraling of the tusks prevents them from growing in a curve.

The tip is also very thin and not pointed. If the big tusks erupt, they are also very pointed at first, but abrade their tips over time. At the next photo you can also see a detail in which it differes from the big tusks. Its foramen apicale, the apical opening of the tooth which connects the pulp with the blood vessels and nerves of the surrounding bone, is only very small. In the big tusks it is fully open, and about the diameter of the whole tooth. This is the area where dentine and cementum are produced and where the tusks continuously grows. The pulp gets its nutrution over the blood vessels which enter the foramen apicale, and here is also the interaction of the sensory nerves with the tusk. But the small vestigal tusks don´t need to grow anymore, nor do they need much nutrition or have any more sensory function, so the apical formanen is nearly closed.

Foramen apicale of a vestigal right narwhal tusk, Kunstkammer Landesmuseum Württemberg, Stuttgart

You can also see that it has a very clean colour, unlike the yellowish erupted tusks, that have often dark veined spiral grooves. This colour comes from algae, diatoms and various particles from the surrounding water and sediments, which can stain the narwhal tusks like coffee does on human teeth.

The unerupted right tusks are also quite variable in shape, as they have nearly no more selection pressure. That is similar to human wisdom teeth, which also show a massive amount of variation, and which can be also vestigal with reduced sizes or aberant shapes of the crowns and roots.

Here is also a photo which shows the tusk in the showcase, together with a number of toadstones (fossil teeth of Lepidotes), a fossil oyster from the Swabian Alps, an ammonite and a large fossil shark tooth:

Vestigal right tusk of a Narwhal, Kunstkammer Landesmuseum Württemberg, Stuttgart

Veröffentlicht unter Anatomie, Wale | 2 Kommentare

A new model of Meyerasaurus – or how to bodypaint a plesiosaur

Today I wanted to show you some photos of a life-sized model of Meyerasaurus, a rhomaleosaurid from the Toracian stage of the early Jurassic, whose fossils were found at Holzmaden. The model was made by my friends from kamyk.pl, a Polish company which specialized in the creation of zoological and paleontological models for museums. I had already the chance to take a close look at some of their wonderful models at the last two fossils fairs at Leinfelden-Echterdingen, the largest anual fossil fair of Europe. One of their latest models – the Meyerasaurus – was made for the Natural History Museum at Lodz, Poland.

Meyerasaurus by kamyk.pl, Natural History Museum Lodz. Photo by Piotr Menducki

Here is another photo of the model:

Meyerasaurus by kamyk.pl, Natural History Museum Lodz. Photo by Piotr Menducki

When the model was already finished and awaiting its paintjob, Piotr Menducki of kamyk.pl asked me for some proposals about possible colour schemes and pattern. So I reflected about possible and probable colours and patterns which could fit with this model. I wanted to avoid too much influence from other models and life reconstructions of plesiosaurs. The reconstructions from the BBC-series „Walking with Dinosaurs“(1999) and „Sea Monsters“ (2003) for example have been highly influential, and even today you can see a whole lot of reconstructions which are clearly based on their designs. So instead of looking at other models and paleoart, I focused on modern marine animals to get some ideas.

Meyerasaurus model by kamyk.pl, photo by Piotr Menducki

There is sometimes a certain tendecy to depict mesozoic marine reptiles with quite fancy colours and patterns similar to terrestrial reptiles. But if you look at modern marine animals, it´s quite noticeable that their main range of colours and patterns is still comparably overseeable. Small and medium sized animals have much more often striking patterns and flashy colours, whereas bigger animals tend to have more uniformous colours and lesser or even absent patterns. Of course this is no rule, more some sort of tendency, with a whole lot of exceptions (like whale sharks or oarfish). But you can see that tendency even within the ontogeny of many animals, particularly in fishes and reptiles. Young komodo dragons, nile crocodiles and tiger sharks – to name just some iconic and well-known species – have very prominent patterns during their youth, which fade more and more when they grow bigger, until they have nearly fully vanished in big old specimens.

So I looked at various sharks, big marine fish, cetaceans, seals and marine reptiles to find certain patterns which we can find in all of those lineages. I started with the leatherback turtle, one of the most amazing reptiles of our time, and in many respects the closest living thing to a plesiosaur. Adult leatherback turtles are usually of a dark mottled grey main colour, with small brighter spots and a brighter area in the area of their throats. It´s notable that younger leatherbacks have also often much more contrast-rich skin with much bigger white skin areas than adult specimens.

Leatherback sea turtle (Dermochelys coriacea), photo from Wikipedia

This combination of different shades of grey, combined with white and black patterns, is very common among a whole lot of highly different marine animals, from mammals, to birds, certain reptiles, sharks, rays and teleost fishes. So it seems really not too far-stretched to assume that many mesozoic marine reptiles were likely somewhere within this range as well. Given the enormous number of known plesiosaurs (plus countless still unknown species) which lived for an incredibly long time in the oceans of the world, we could probably bet that they had not only a lot of variation in colours and patterns, but also that at least some were really within the most common colour schemes of modern marine animals of comparable size.

The combination of mottled grey as a main colour, combined with brighter areas at the ventral parts of the body and some lighter or darker spots seemed to be a good and reasonable concept.

If you look at mammals, you can also find species which resemble the pattern and colours of the leatherback, for example the infamous leopard seal (Hydrurga leptonyx).

Leopard seal (Hydrurga leptonyx), photo from Wikipedia

Another photo of a leapard seal, which shows the head in detail:

It´s really interesting how there are not only many different shades of grey, ranging from silvery-white to dark grey, but also bright and dark spots as well. Many other seals have very similar coats, for example harbour seals or grey seals, and to a lesser degree also mediterranean monk seals.

Among cetaceans, the Atlantic spotted dolphin (Stenella frontalis) fits also quite well herein, but there are also many other cetaceans with lesser pronounced spots which have a quite non-uniformous mottled grey skin. Another interesting, and rarely seen example would be subadult narwhales, which are still much darker than adults. It is also quite important to keep in mind that many cetaceans have a surprisingly high intraspecific variation of colours and patterns, depending on age and sex.

It is also quite important to keep in mind that the very common idea that aquatic animals show countershading with darker dorsal and lighter ventral areas is also not a universal rule, but also more a tendency. Many seals and cetaceans are for example nearly fully dark, like sea-lions or false killer whales, whereas some like the super-bizarre strap-toothed whale Mesopodon layardii show even some negative countershading whith large whiteish dorsal areas. In many cases you see also only small white ventral areas, for example around the mouth of throat, or sometimes also in the pelvic area, like in sperm whales or Southern right whales.

Here is also a photo of a salmon shark (Lamna ditropis), which I show here for obvious reasons:

Admittedly, that´s not a very common pattern for pelagic sharks, which are in general without distinct spots, except for markings on the fin tips. That reminds me also on a story I experienced some years ago. I was at late evening in a rockabilly bar, when I accidentally heard a conversation of an older and already somewhat drunk punk with another guy. I have no idea what their conversational topic was, but one sentence sticked in my mind:

„The great white shark isn´t white at all, it looks more like an old filthy car.“

That´s really the coolest description of Carcharodon charcharias I´ve ever heard, and there is really something to it.

Another example of a cartilaginous fish with dark main greyish colour and bright spots, even one from tropical areas, the spotted eagle ray  (Aetobatus narinari):

And just for the case that the leopard seals, the salmon sharks or the narwhales give you still somehow the impression that this fits better into colder areas, take a look at this wonderful ocean sunfish (Mola mola):

Ocean sunfish (Mola mola), photo from Wikipedia

It is also noteworthy that some comparable colour schemes can be even found among some marine snakes.

Of course it is still fully speculative to give a plesiosaur some variation of the shown patterns and colours, and perhaps some of them were really much more colourful in life. But on the other hand it is perhaps still more likely than some fully speculative fancy colours and patterns which we see in no or only extremely few modern marine animals. In any case, the team of kamyk.pl did a really good job when they painted their Meyerasaurus.

Here is also a photo of the original fossil, exhibited at the Museum am Löwentor, Stuttgart:

Veröffentlicht unter Evolution, Fische, Haie und andere Knorpelfische, Paläontologie, Skulpturen, Wale | Hinterlasse einen Kommentar

A King of Cods

Today I want to show you a „Dorschkönig“ or „king of cods“ from the collection of the Zoological Museum Kiel:

„King of cods“  was the Name given by fishermen to Atlantic cods (Gabus morhua) with a rare cranial malformation of the head which results into a pug-face-like shape. This specimen was caught in the waters of Eckernförde in 1869 and was part of the ichthyological collection of zoologist Karl August Möbius.

This kind of malformation is not just found in cods but also known from many other fish species. You can see another example of a small king of cod specimen here. In salmonids this can be for example the result of an infection with Myxobolus cerebralis, a myxosporean parasite which can affect the skeletal development in young fish. But there are of course also other factors which can lead to cranial deformations, so it is often quite hard, if not impossible, to trace back the original cause.

Veröffentlicht unter Bild des Tages, Fische, Teratologie | Hinterlasse einen Kommentar

The bearded Leviathan – not your everyday Basilosaurus

Basilosaurus – the great mammalian leviathan of the Eocene – was beyond doubt one of the most spectacular creatures which ever swam the oceans of the world.  But despite the fact that fossils of this ancient cetacean have been known since well more than one and a half centuries, many aspects of its anatomy and biology still remain enigmatic. I´ve written in an older blog article why archaeocetes were surely not the skull-headed and shrink-wrapped pseudo-reptiles as which they are usually depicted. They had surely much more soft-tissue around their skulls and necks than most people think, and also nearly certainly possessed  well-visible and functional vibrissae (see here why). Dominic Grabowski recently created this truely wonderful life-depiction of a chunky Basilosaurus with volumous upper lips, and countless fine vibrissae on its chin and upper lips.

Basilosaurus by Dominic Grabowski

I think this is really one of the most life-like depictions of an archaeocete I have ever seen, and despite its unconventional appearance, it really doesn´t look wrong. Dominic managed to blend the features of a whale with those of a hippo in a really good way. If you take a close look, you can even see fine isolated hairs covered the rest of the body. This is of course fully speculative, but plausible. We just have no idea how and when exactly whales lost their fur. With few exceptions like walruses and to a lesser extreme degree elephant seals as well, modern seals have all a fairly well developed coat. So were those derived but still partially amphibious protocetids like Maiacetus still fully covered by fur as well?

Well, we´ll just never know. But those animals mainly lived in comparably warm subtropical or even tropical areas, and I could well imagine that they lost most of their coat at a quite early stage – similar to modern hippos and the even more terrestrial pygmy hippos. And it´s really interesting to keep in mind that they didn´t just lost their whole fur, but just highly reduced it, similar to other „bald“ mammals (including humans). Hippos and even manatees and dugongs have fine isolated hairs all around their bodies. It could be possible that they have some tactile function, similar to the more specialized vibrissae in the facial area, and it seems not unplausible that such hairs could have been still present in animals like Basilosaurus.

 

Veröffentlicht unter Paläontologie, Populäre Irrtümer, Säugetiere, Wale | Hinterlasse einen Kommentar

Why maned lionesses are not that special (and why they don´t baffle scientists)

Perhaps you have heard about the recent report about a lioness at Oklahoma City Zoo, which „mysteriously“ grew a mane. As usual „scientists are baffled“, at least according to the news-site which spreads the story.  However, the whole case is neither mysterious nor that unusual. The lioness at Oklahoma Zoo, her name is Bridget, is already 18 years old, what´s quite old for a lion, far older than they usually they live in the wild. Even big cats age, and like humans, they also can have a menopause, and as a consequence thereof, a change in the production of sexual hormones. We all have male and female hormones in our bodies, which are in a quite complex interaction with our metabolism. Changes of the hormone levels can result into a lot of physical changes, from increased or decreased muscle growth, accumulation or breakdown of body fat or the reduction or reinforcement of secondary sexual characteristics like body hair.

In lions, the growth of manes is controlled by testosterone (similar to the growth of beards in humans), so changes in the level of this hormone can result into an increase or decrease of mane growth (the whole thing is of course even much more complex, and also depends on the subspecies of the lion). And it doesn´t matter if it is a male lion of a female lion. A male lion with very low testosterone levels will hardly grow a mane, whereas a female lion with high levels of testosterone can grow a small mane. The origin of such an inbalance can be quite variable. It can be a congenital defect, a dysfunction of hormone producing organs or a hormone-producing tumor for example. It can be (more likely in males than females) a result of an accidental or artifical removal of the gonads. Something like that is likely if a comparably young lion shows for example a mane which is atypical for its sex. But if a lion, which has been totally normal for its whole life, starts to exhibits unusual mane growth at old age, it is highly likely a result of the hormone imbalance after the menopause. The production of typical sexual hormones decreases, and the effects of the normally suppressed antagonistic hormones can become more visible.

I have seen such cases myself. There were two lion-sisters at Stuttgart Zoo, Schiela and Elektra (both 1994-2008), which grew both a well visible mane at old age. Here is a photo of one of them, which I took in 2003:

Maned lioness at Wilhelma Zoo, Stuttgart 2003

As you can see, the mane resembles those of a young male lion which just hits puberty. It´s neither as long, nor as extensive or dark as those of a typical male lion. It is more the feline equvialent of the facial hair seen in some (often more elderly) women.

Lioness with mane, Wilhelma Zoo, Stuttgart, 2003

It was sadly not that easy to take photos of her, but you can see some better ones here, here and here.

Schiela and Elektra were also not the only other known case of old lionesses with manes, and there is really nothing about them that would baffle scientists.

Lioness with mane, Wilhelma Zoo, Stuttgart, 2003

 

Veröffentlicht unter Populäre Irrtümer, Säugetiere, Teratologie | Hinterlasse einen Kommentar