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

Publiziert am 4. November 2018 von Markus Bühler

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 | Schreib einen Kommentar

The amazing Nautilid Diversity of the Post-Cretaceous Seas

Publiziert am 24. Oktober 2018 von Markus Bühler

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 | Schreib einen Kommentar

The Narwhal´s lesser Tusk

Publiziert am 22. Oktober 2018 von Markus Bühler

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

Publiziert am 12. September 2018 von Markus Bühler

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 | 2 Kommentare

A King of Cods

Publiziert am 17. Juli 2018 von Markus Bühler

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 | Schreib einen Kommentar

The bearded Leviathan – not your everyday Basilosaurus

Publiziert am 2. Mai 2018 von Markus Bühler

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 | Schreib einen Kommentar

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

Publiziert am 27. Februar 2018 von Markus Bühler

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 | Schreib einen Kommentar

Photo of the Day: Chiemsee Pike

Publiziert am 20. Februar 2018 von Markus Bühler

Pikes have always been among my favourite native European freshwater fishes. Their taxonomy has  become much more complex in recent years, when two additional European species were described, so that Esox lucius is no more the only of its kind in Europe. This particular topic will (hopefully) anytime be featured in a more extensive blogpost about the amazing diversity of pikes.

Last year was a particularly good one for me in terms of finding pikes in the wild. Besides some really impressive specimens I saw during my trip to Königssee and three small ones I discovered in a lake at the Swabian Alps, I could also take some underwater photos of several young pikes at Chiemsee. This one is likely the best, which shows a pike of around 15-20 cm:

Northern Pike, Lake Chiemsee

You can see very well how the camouflage pattern of the pike blends within the structure of the underwater vegetation.

Veröffentlicht unter Bild des Tages, Fische | Schreib einen Kommentar

The Art of Xylotheques – Wooden Books about Woods

Publiziert am 18. Januar 2018 von Markus Bühler

Xylotheques are quite likely the most artistic and beautiful examples of herbaries. Dating back to the early 18th century, they were still to some degree made in the tradition of the old cabinets of curiosities, which combined all fields of nature with arts and crafts. They were dedicated to educate about the characters and traits of the various trees and shrubs of a certain area.

In contrast to a simple casebound herbary, which usually only includes preserved leaves and other pressed parts of a plant, the „books“ of a xylotheque also includes the massive wood and often many more parts of a tree. Every book is made from the wood of one kind of tree or shrub, with the spine of the book covered with bark, and sometimes even specific lichens.

The insides can include dried branches and leaves, seeds, cones, little wooden containers with pollen and standardized cubes of wood to show its  specific weight. There can be also cross-sections of branches, dried roots and charcoal.

The backbone of the book has also a removable panel at the inside, with a piece of paper with a written description of the tree and the content of the book.

There were never many xylotheques, and they have been always quite worthy, as it was quite expensive to make them. This examples are from the xylotheque exhibited at the University of Hohenheim, which includes a large number of wooden books from two different series.

This smaller books are lesser complex in construction and also include not as much inventory:

 

 

 

Veröffentlicht unter Curiosity of the Day | Schreib einen Kommentar

The Tarbosaurs of Warsaw

Publiziert am 10. Dezember 2017 von Markus Bühler

Last year I made a city holiday at Warsaw and took the opportunity to visit a lot of museums there. I was especially eager to see the Museum of Evolution, which is located in the monumental Palace of Culture and Science. One of the exhibition rooms has a whole gang of Tarbosaurs on display, including some famous specimens. Tarbosaurus gets much lesser attention than Tyrannosaurus, so I thought this would be a good chance to post some photos of the skeletons at Warsaw.

That´s likely the most famous one:

The information table next the the left skeleton is around 1,8 m in height, so this specimen was only a subadult with a hip height of not much over 2 m in life, with a total length of somewhat over 4 m or so.

.

Tarbosaurus and Tyrannosaurus seem really quite similar at first look, but if you look at the proportions of their skulls, you can see that the one of T-rex was significiantly more massive and especially also much broader.

.

.

.

.

A photo which shows how the specimens was excavated:

.

There is also a cast of a complete skeleton of a pretty big specimen, which easily dwarves the other skeletons nearby.

.

It was not easy to get them all completely on a photo, but it gives you an idea about the massive size difference.

There was also a cast of another skull and some isolated bones as well:

.

.

.

And last but not least some old paleoart:

Veröffentlicht unter Dinosaurier | 4 Kommentare