A possible case of tail autophagy observed in Lilford’s wall lizard on Dragonera

In 2014, I made a trip to Dragonera, a small island off the west coast of Majorca. My main focus was to see the endemic variant of Lilford´s wall lizards, Podarcis lilfordi ssp. giglioli, which populates this island. Among the countless specimens I´ve seen there, one was of particular interest. It was a male with a freshly autotomized tail, which was just in the act of swallowing a lizard tail. I sadly managed to take only a single photo of if, and at the time I´ve seen it, I assumed that it was probably consuming the tail of another lizard. Well, that could have been the case, but it could have been even weirder, and it was not eating the tail of another lizard, but its very own tail.

Possible autocannibalism of Podarcis lilfordi ssp. giglioli on Dragonera. Photo Markus by Bühler.

Autophagy or autocannibalism is not even that rare, a lot of animals habitually consume own body parts, like the shed skin of amphibians or the placenta which is often consumed by female mammals after birth, and degus gnaw off their own dried tail bones when they have lost the superficial skin by autotomy.

There are also a few documented cases of skinks, lacertid lizards and even tuataras which had eaten their own autotomized tails. One such a case was recently observed and photographed on the Iberian Peninsula in 2013. During a fight between two males of Iberolacerta monticola, one of the contrahents lost its tail. When the lizards detected their human observers, one of the males fled, but the tail-less specimen started to consume the tail it had just autotomized.

Photo from Iglesias-Carrasco, M. & C. Cabido 2016, used with permission by Carlos Cabido (thank you Carlos!):

Iberolacerta monticola eating its own autotomized tail

Perhaps the opportunistic consumption of the own tail after such fights is practized as a compensation for the energy stored in the tail, which would be otherwise completely lost.

I have sadly not observed what happened before I discovered the tail-eating lizard on Dragonera. So I don´t know if it really consumed its own tail, or the tail of contrahent after a fight, or – also possible -opportunistically an autotomized tail which it just found. I will never know. But given the fact that it had a very fresh tail stump it is still well possible that it really was such a rarely photographed case of tail autophagy.

Reference:

Iglesias-Carrasco, M. & C. Cabido 2016. A case of tail autophagy in a male of the Iberian rock lizard, Iberolacerta monticola. Salamandra 52 (2): 215-216 available here

 

Veröffentlicht unter Naturbeobachtungen, Reptilien | Hinterlasse einen Kommentar

No guts, no glory – Nanuqsaurus feeding giant petrel style

In the sequel of the last post about the table manners of living and prehistoric carnivores and their depictions in paleoart, I post today a portrayal of Nanuqsaurus feeding on a mosasaur carcass by Joschua Knüppe (take a look at his awesome art here):

Nanuqsaurus feeding giant petrel style by Joschua Knüppe

Joschua made this nice depiction after we had an interesting discussion about the possible life-appearance of Nanuqsaurus hoglundi, a small tyrannosaurid from the late Cretaceous which was found in the Alaska North Slope. Nanuqsaurus nearly certainly experienced quite cold climates on occasion and had to deal with bad weather. Joschua made his Nanuqsaurus reminiscent of a giant petrel (Macronectes giganteus) (earlier covered here), a very large antarctic seabird with very nasty eating habits. And like giant petrels, which have their heads often fully covered with blood when they scavenge on the carcasses of dead seals, this Nanuqsaurus has its mouth and snout also smeared with the blood of a dead mosasaur it found washed ashore. It looks also suprisingly similar to this komodo dragons feeding on a dead dolphin, despite the dirty whiteish plumage.

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Don´t forget the blood and guts – for the sake of badass feathered theropods

Feathered theropods have some issues. A lot of people just don´t like them. Movies like  „Jurassic World“ have also shown that the mere idea of theropods being mainly covered in some sort of feathers or filaments is still far away from getting general acceptance. One of the reasons for this, and probably an especially important one concerning the movie industry, is the fact that many people find the image of a theropod with feathers instead of scaly skin just not scary enough. For some reason feathers are often automatically mentally connected with such little frightening birds like chickens, what usually results into a massive downgrading of respect. And that´s what often gets stuck in the minds of people, phrases like „T-rex was just a giant chicken“.

What those people completely forget, is that domestic chickens make up only a tiny fraction of the more than 10.600 species of modern birds, and that they are obviously not the best comparison for large to giant predatory theropods. People should really stop to think about chickens when they think about big feathered dinosaurs, but more about birds of prey, vultures and other modern carnivorous birds. Some of them are really awe-inspiring and aggressive carnivores, and there is obviously a reason why birds of prey – eagles in particular – gained so much respect in so many cultures around the world.

One reason why feathered theropods are not exactly popular in the general public is also perhaps due to their common depictions. A lot of the early and still often used illustrations show just something that looks like a dinosaurs with fuzzy feathers glued on parts of their skin. This actually looks often rather goofy. Sadly it´s especially that kind of depiction which is most widespread in the medias, thanks to certain poorly animated theropods in various documentaries. Luckily things have started to change, and more and more illustrations are now out there, which show much more realistic and visually appealing attempts to visualize feathered theropods. Some of them look really fantastic, and I am especially fond of the beautyful restaurations by John Conway.

But again, we face here the constant complainers who don´t want to see feathered theropods, because they look in their views not awesome and badass enough, what often even results into open sketisms about the very existence of feathers in many theropods, despite the overwhelming fossil evidence which emered over the last years. But to cling on scaly theropods just because they allegedly look more badass than those with feathers makes about as much sense as to hug the outdated idea that vikings really wore horned helmets and double-axes because someone thinks they look more awesome.

Perhaps one way to counter this problem could be to show those people that even feathered theropods actually could have looked really nasty. Nature can be extremely cruel, and we are often not used to see all those cruelty and nauseousnes which is part of the natural life. Even many nature documentaries often don´t show the most brutal and disturbing scenes.

We also forget often very quickly that even familiar animals which we know from zoos and which we find cute and beautyful, can be also highly dangerous and deadly as well. The same polar bear which looked before like a huge teddy bear is suddenly no more that cute at all, when it´s all over covered with blood or feasting on mangled carcasses. It´s the same with big cats, as beautyful as they are, they are still among the most dangerous predators of the world, which sometimes still consider our own species as nothing but prey. Their beauty is also quickly gone, when you see them dripped wet with blood, and their resemblance to an oversized housecat easily vanishes when you see photos like this, and I hardly doubt much people would be eager to pet this blood-covered cubs anymore.

Sometimes the beauty can be a beast, and even a beast can be beautyful. Even the majestic lion doesn´t look much more adorable than a komodo dragon defleshing a blood-oozing whale carcass, when its mane is soaked with blood.

And this doesn´t only apply to mammals and reptiles, but to birds as well. If you look at those modern birds like marabous, vultures or giant petrels which feed either on large prey or on carcasses, you can get an idea how it could have looked when theropods were feeding on entrails, gobbling bones, or literally bathing in blood. Things like this doubtlessly happened  on occasion, when theropods were feeding on larger prey which was too big to be eaten whole. And I really don´t think that the presence of feathers makes them lesser scary, in fact, I would even say that blood-soaked plumage looks even more gory than blood on scales.

Just take a look at this awesome giant petrel, splashed with the fresh blood of a dead fur seal, or this incredibly badass fighting giant petrels with all of their beaks and heads stained red. And if you have a strong stomach, take a look at this video of a giant petrel disembowelling a penguin alive and feeding with an accomplice on the living flesh of the fleeing victim.

With all this in mind, remember that a giant petrel is just the size of a goose, with short legs and waddle feet, unarmed wings with feathers and a toothless beak. Now try to imagine one of the larger theropods, surpassing every lion or bear in size, with meat-hook-like claws on its arms, long muscular legs and  which would outrun every human with ease and with jaws full of sharp-edged teeth, ripping the bowels out of its prey, the whole jaws and head stained red and blood soaking into its feathery filaments with sanguine drops running down its neck. Would this still look lame?

My artistic abilities are only quite limited, and I have sadly not much experience with brushes and paint, but some time ago I made a try with water colours on cardboard to depict the dromaeosaurid Tsaagan from the late Cretaceous of Mongolia in a style which should now feel familiar to you. I deliberately chose a pretty small theropod, which comes in its overall head shape at least vaguely close to a giant petrel. I also covered much of the teeth with lips and gave its plumage some volume.

Tsaagan by Markus Bühler

Tsaagan by Markus Bühler, watercolours on cardboard

Perhaps I can encourage with this blogpost some artists who are more skilled than myself to include some blood and guts at least on occasion into their paleoart, to show that feathered theropods could have been also badass and scary, and as a reminder that nature always had its brutal and gory sides.

Veröffentlicht unter Dinosaurier, Paläontologie, Populäre Irrtümer, Vögel | 3 Kommentare

A natural crystal skull

Some time ago I visited the mineral exhibition at the museum „Welt der Kristalle“ near Rottweil. Besides a lot of really fascinating crystals and minerals and some nice fossils was a really bizarre object on exhibit, a ram skull fully overgrown with fine selenite crystals.

This skull comes from Queensland, Australia.

It´s obviously not a very old skull, and the crystals must have grown within a time of no more than some decades.

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A herring in the wolf´s clothing

Today´s blogpost features another fish skull, this time a much smaller but yet pretty impressive one, which nearly looks like a miniature version of the giant cretaceous Xiphactinus.

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Dorab wolf-herring (Chirocentrus dorab) skull, Museum Schloss Rosenstein, Stuttgart

It belongs to a dorab wolf hering (Chirocentrus dorab), a member of the Clupeiformes, what makes it a close relative of herrings, anchovies and sardines. Quite in contrast to those usually filter-feeding planctivores, wolf herrings are voracious predators with huge gaping jaws and enormous teeth. Iy you look at the skull you can see not only the very large teeth in the lower jaw, but also a pair of nearly spear-like teeth in the middle of the upper jaw.

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There are only two species of wolf herring, the dorab wolf herring and the whitefin wolf herring Chirocenturs nudus.

Except for the size, which doesn´t exceed a metre, the head and body shape of wolf herrings is really suprisingly reminiscent to Xiphactinus.

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Dorab wolf herring, photo from Wikipedia

Here is a photo of „Mildred“, a gigantic Xiphactinus audax specimen of 5,6 m, which was kindly provided by Anthony Maltese (thanks again!).

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Xiphactinus audax, photo by Anthony Maltese

Of course there are various differences, but the similarities of the overall body shape and the functional anatomy of the skull and jaws are still surprising. Here is another photo of Mildred´s giant skull, which shows the same combination of a very steep upper jaw combined with a massive mandible and big teeth:

Xiphactinus audax skull, photo by Anthony Maltese

Xiphactinus audax skull, photo by Anthony Maltese

 

Veröffentlicht unter Anatomie, Fische, Paläontologie | Hinterlasse einen Kommentar

Relics of a River Monster

Yesterday I had a great day visiting the Museum für Naturkunde at Schloss Rosenstein, Stuttgart, and later also the nearby Wilhelma Zoo. There was a special exhibition at the museum with a lot of specimens which are usually not on display, including a huge skull of an Atlantic salman (Salmo salar).

Huge skull of an Atlantic salmon (Salmo salar), Schloss Rosenstein

Huge skull of an Atlantic salmon (Salmo salar), Schloss Rosenstein

It dates back to 1858 and comes from the Rhine Falls, one of the three largest water falls of Europe. Once the river Rhine was the most important water for salmon fishery in whole Europe, but this times are long gone. As a result of overfishing, control stucture and especially heavy pollution, the Atlantic salmon fully vanished from this river by the middle of the 20th century. Since water quality has increased again and as the stream was stocked with young salmons, the species is very slowly again on the rise, but it will still take decades until it will form again healthy and self-maintaining populations.

This skull belonged to a male, what´s clearly obvious if you look at the hook-shaped jaws. If you look below the mandible, you can also see the dislocated tooth-covered boney part of the tongue.

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This particular specimen was really quite big and is a good reminder that the Atlantic salmon, which reaches exeptional lengths up to around 1,5 m, is one of the largest freshwater (ok, anadromous…) fishes of continental Europe. Here is a photo of the showcase where the skull was situated, to give you an idea about its huge size:

Huge salmon skull

Huge salmon skull

The skull above it belongs to a spectacled bear and the deer skull on the right to an adult roe deer buck, the one in the middle on the left to a subadult harbor porpoise. This brings to mind that megafauna is not just a term exclusive to terrestrial animals, but that it applies to aquatic creatures as well. And alike the terrestrial megafauna, the giants of the rivers and lakes have sadly also vanished in many parts of the world. Many large streams of Europe were once full of big and even giant anadromous fishes, like the Atlantic salmon and several species of sturgeons, but all of them have decreased extremely in number or became nearly fully extinct.

Veröffentlicht unter Anatomie, Bild des Tages, Fische, Museen | Hinterlasse einen Kommentar

Fossil of the day: Pelagosaurus typus with fatal jaw fracture

Today I visited the fossil museum at Dotternhausen, which exhibits nearly exclusively fossils found in the surrounding area. It is located in the Swabian Alps, an area which is famous for various fossil deposits, especially for ammonites and other marine invertebrates. There are however also some very nice vertebrate fossils on display at the museum, including a spectacular fossil of a subadult Pelagosaurus typus, a small basal marine teleosaurid from the Toarcian which grew not larger than around 3 m. This particular specimen shows a quite dramatic pathology of the lower jawabone. The mandible fractured around halfway in its middle and pointed nearly rightangled downwards.

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Pelagosaurus typus with fractured mandible, Fossilienmuseum Dotternhausen

This was neither a postmortal artifact nor something that happend just prior to the death of this hapless little crocodylian. It must have lived for a considerable time with this broken mandible, as the fracture healed and formed a massive callus at the ends of the fractured bones.

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Broken jaw with callus

Comparable jaw fractures of lower and upper jaws are also known from modern crocodylians as well, especially very long-snouted species like gharials. Sometimes considerable parts of the jaws are even fully missing, and they are sometimes still apparantly doing well. This shows that it is not necessarily always fatal if a large part of one of the jaws is missing or so malformed that it becomes functionally absent. The very strong deformation of the mandible, the small size of the subadult specimen and the fact that this was a pelagic predator however could well indicate that the deformaty was a strong handicap for hunting and lead eventually to starvation.

Here is a photo of the whole skeleton:

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Myotragus balearicus – an extinct goat with anthropomorphic face and reptile-like growth pattern

Long before the first primitive domestic goats were brought to the Balearic archipelago by early human settlers, another caprid already populated the islands of Majorca and Minorca. This remarkable ungulate, Myotragus balearicus, was about the size of a small domestic goat. It had a lot of really weird anatomical features, like eyes facing towards the front, a unique pair of perennial-growth  lower incisors which resembled somewhat those of rodents and a very shortend facial skull, somewhat resembling those of certain domestic goat breeds. It had also unusually short legs for a bovid and a strangely shaped sturdy body and a

Myotragus balearicus skull from the archeological exhibition of the Museu Diocesà de Menorca at Ciutadella, Mahon

Myotragus balearicus skull from the archeological exhibition of the Museu Diocesà de Menorca at Ciutadella, Minorca

If you look at the skull above I photographed at the Museu Diocesà de Menorca at Ciutadella, you can see the unusual direction of the orbits. The common condition in ungulates are orbits situated on the sides of the skull. Myotragus must have looked quite weird in life, nearly somewhat like an anthropomorphic animal character from a story book. Take a look of this life reconstruction in frontal view to see what I mean.

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Sadly this was only a cranium without the mandible, but you can also see the very short facial skull and the quite robust molars. It had also quite small horns for a wild caprid, as even the males didn´t have larger horns than seen in this skull.

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Dorsal view of the skull:

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One of the most remarkable pecularities of Myotragus was its growth pattern, which was unlike any other known mammal. Its metabolism adapted to changing environmental conditions, like the availability of food, causing irregular growth patterns with intermittent phases in which growth fully ceased. It took also a very long time until they reached somatic maturity at around 12 years, what´s extremely late for such a small ungulate. This growth pattern is unique among modern mammals and resembled much more those of an ectothermic reptile.

It´s really a misfortune that we missed this extraordinairy animal only for a comparably short time. Myotragus was not one of those fabulous beasts which already became extinct tens or hundreds of thousands or even millions of years ago, but disappeared -in geological terms- quite recently, around 5000 years ago, after the Balearic Islands were populated by humans.

Myotragus balearicus restoration, Photo from Wikipedia

Myotragus balearicus restoration, Photo from Wikipedia

Surprisingly this reconstruction doesn´t even look that odd, what´s perhaps also because it resembles certain common domestic goat breeds with shortened facial skulls short horns and short legs.

Veröffentlicht unter ausgerottete Arten, Paläontologie, Säugetiere | Hinterlasse einen Kommentar

The Bronze Age feral goats of Majorca

The last post covered the Cretan kri-kri, an extremely archaic feral domestic goat which still highly resemebles its wild ancestors. There are however also other, very primitive feral goats on other parts of the world, like the wild goat of Majorca, which gives us a vivid idea about the early history of their domestication.

I was lucky to encounter some of those wild goats some years ago near Alcúdia in the north-east of Majorca. There are also feral goats in many other parts of the island which are descendents of modern breeds, but the true „wild“ goat has a much more ancient origin. This goats were brought to the island around 4000 years ago by the Phoenicians.

Recent work has shown that they most likely descend from hybrids between the Cretan wild goat (Capra aegagrus cretensis) and the bezoar ibex (Capra aegagrus aegagrus).

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Majorcan wild goat near Allcúdia

In contrast to the other feral goats on the island, which show a very large variation of colouration, horn shape and horn size, the wild goats are quite uniformous. They are mainly of a reddish brown, with a dark stripe running down the back and over the shoulder area to the legs and have short fur. They have always horns, which are especially impressive in the males.

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The wild goats in this area are not very shy, so I could ovserve them from a very close distance.

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The flight initiation distance of the goats in this particular area is quite small, and they apparantly don´t care much about the people walking around.

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The total population of the wild goats is around 1000, whereas the total number of feral goats on the island is around 25.000.

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Despite their very small population size, there is still limited trophy hunting for the males.

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This goats show already much more differences from their ancestral forms if compared with the kri-kri, but still appear a lot like a real wild ungulate.

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I could also see this irritating behavior of a billy goat. I have once seen a domestic goat in a zoo doing this too.

Don´t aks, it´s exactly what it seems to be.

Don´t ask, it´s exactly what it seems to be.

Here are some normal feral goats I photographed near Pollença.

Normal feral goats near Pollenca

Normal feral goats near Pollenca

The nature of Majorca is really awesome, and the island is worth to visit for many reasons. But if you make a holiday on the island, don´t forget to take a look at the hybrid bronze age feral goats.

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The kri-kri – a relict feral goat from the stone age of Crete

Goats were after dogs most probably the earliest animals which were domesticated by humans. This happened around 13,000 years ago in the Near East, when people started to keep and breed wild goats (Capra aegagrus) instead of just hunting them.  Goats are a source of meat, hide, fur and horns (milk and dairy products were originally probably much lesser important than in later more productive breeds), they are quite modest and comparably easy to handle, especially when compared with much larger and potentially much more dangerous ungulates like wild boars, wild horses, aurochs, water buffaloes, dromedaries and camels. For this reason, early domestic goats reached already a wide distribution and were even transported to distant islands in some cases. Sometimes those still quite wild goats became feral and lived again the lives of their undomesticated ancestors.

In the case of the kri-kri, we see the fascinating case of such a stone age goat which managed to survive into the modern times in the wilderness of the island of Crete. Originally assumed to be a subspecies of the wild goat, it was found to be a very primitive domestic form, which was brought to the island during the Neolithic Age.

When I was some years ago at Crete I had the chance to see some of those beautyful goats at the municipal park of Chania.

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There was an billy goat with a huge pair of horns. As you can see on this photo, they were not just long but also extremely wide-spaced.

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It used the tips of its enormous horns to groom its back and flanks.

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Here is a younger male specimen which had still much shorter but already impressive horns.

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A map from Wikipedia showing the location of the island of Crete:

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Sadly the kri-kris suffered badly from overhunting, especially during WWII. At one time only 200 specimens were left. Today there are again around 2000 of them, which are mainly living in the remote mountain areas in the southwest of the island, in particular in the area of the Samariá gorge and the surrounding national park area. The Samariá gorge is one of the most awesome geological phenomens of Europe, and really worth to visit.

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You can wander along its whole length from the mountains down to the sea. But should you ever do this, keep some important things in mind. Wear good hiking boots, as the area is really steep and you have to walk over sometimes wiggling rocks, wear headgear and use a strong sunblocker because there are longer parts nearly without any shadow, and the gorge heats up strongly in the sun. And perhaps most important of all, if you choose the way down the gorge to the small village Agia Roumeli, buy a ticket for the fairy which brings you back to the village Sougia BEFORE you start the tour.  Otherwise it can happen that you get stranded at Agia Roumeli, because the ferry is already outbooked and you have to wait for many hours at this shadow-less roasting pan-alike part of the earth. Agia Roumeli is located near to mouth of the gorge at the coast and is only accessible from the gorge or by sea.

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I have sadly not seen any wild kri-kris in the gorge, but I found a corpus delicti which clearly prooved their presence:

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This partially mummified skull was lying on the ground, without any surrounding bones. It is well possible that the smaller parts were already all eaten away by the bearded vultures which also populate at small numbers the gorge.

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I saw also a partial kri-kri cranium with a huge pair of horn cores at the small archeological museum of Kissamos. Sadly it was not allowed to take any photos. But it could indicate that kri-kris had possibly prior to millenias of trophy-hunting and decades of genetic depletion also even bigger horns than seen today.

Veröffentlicht unter Naturbeobachtungen, Säugetiere | 1 Kommentar