The oral oddities of ruminants

In the last post I wrote about the strange anatomical structures in the beaks of spoonbills. This time I will cover again oral oddities, but in a fully different class of animals. Ruminants have always been among the most important game for humans, and in the form of their domesticated varieties among the most important animals in the history of mankind. Sheeps, goats, various domestic bovines and domestic reindeers were essential elements of whole cultures, and even today huge industries are build on some of them.

So it is not surprising that we normally do not think of anything really weird when we look at those animals. That´s probably in part because we usually don´t come really close enough to them, but also because most of us usually don´t butcher or dissect them ourselves.

But if you do so, you can find anatomical structures of nearly alienesque weirdness. If you have seen photos of the mouth cavities of leatherback turtles (Dermochelys coriacea), you will know about those totally crazy spine-covered papillae which help them to engulf such slippery prey like jellyfish, and which also line the whole length of the esophagus (actually Dermochelys isn´t the only marine turtle with such papillae, only the most famous one to have them).

But as grotesque as those spinous papillae of leatherback turtles seem, they aren´t even that different from very similar structures found in the mouth cavities of ruminants like for example ordinairy domestic cows or sheep. One good way to see them in all their strangeness, is to dissect a ruminant head,. That is a great possibility to see even the normally not visible parts inside the mouth, and all the extent of the oral papillae.

But sometimes you can also have the chance to see them in a living animal. Last year I visited the wildlife park Wildparadis Tripsdrill, a really very nice park with a very large number of interesting animals, mainly from the Northern hemisphere. Many of the ungulates there are used to eat the pellets which are sold for visitors. Besides various deers, muntjaks, mufflons and some other ones, there are also domestic yaks (Bos grunniens), which are eager to beg for pellets.

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Subadult yaks at Wildparadis Tripsdrill

Now let´s look in their mouths.

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Closer.

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Even closer:

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The whole insides of the cheeks and some other, in this photo not visible areas, are covered with weird tentacle-like villi. They are directed towards the gullet, and form together with the much smaller papillae on the tongue a conveyer system for plant matter.

Another photo taken from the side:

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Besides several still not fully grown subadults, there was also a highly impressive bull, which was also quite willed to show the inside of its mouth.

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The bull had also really formidable horns and striking elongated neural spines.

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Even given the fact that domestic yaks don´t grow as big as their wild relatives, this bull was still a highly powerful and beautyful being.

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And it had a nice white beard as well.

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Those villi are more or less soft, but some of them, in particular those in the lower corner of the mouth, have well pronounced keratinized tips which extends into short spines.

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And what looks at that perspective nearly like some alien slug radula is still only a quite normal bovine mouth.

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The tongues, cheeks and other elements of the oral cavities of many animal are highly specialized, sometimes even extremely grotesque by human standards, but they usually still don´t get much attention.

Veröffentlicht unter Anatomie, Säugetiere | Hinterlasse einen Kommentar

Birds with weird beaks part III: Why spoonbills are even stranger than you think

Spoonbills (Plataleinae) have obviously weird beaks. The overall elongated shape with the flat and proximally widened end is already a quite strong modification of the „normal“ bird beak. But you have to take a really close look at the beak, to see another, much lesser obvious anatomical feature, which makes it even more bizarre.

If you take for example the Eurasian spoonbill (Platalea leucorodia), a bird of quite exotic appearance which surprisingly even breeds in low numbers in great Britain, Denmark and Germany. The proximal half of its beak is nearly absurdly thin and flat, with the epynomous spoon-shaped end. That´s what people usually look at and immediately know why it´s called spoonbill.

Eurasian spoonbill (Platalea leucorodia), ornithological museum at Rocca di Lonato

When you look however in the distal part of the beak, you won´t not only notice some fine transverse ridges on the upside and margins of the beak, but also some strange keratinous structures at the inside.

Eurasian spoonbill(Platalea leucorodia), ornithological museum Rocca di Lonato (2)

And that´s how they look in a more lateral view:

Eurasian spoonbill(Platalea leucorodia), ornithological museum Rocca di Lonato (7)

I made another photo without flashlight, to make it somewhat more contrasty.

Eurasian spoonbill(Platalea leucorodia), ornithological museum Rocca di Lonato (4)

And for comparison one with flashlight:

Eurasian spoonbill(Platalea leucorodia), ornithological museum Rocca di Lonato (5)

That´s it, there are numerous conical peseudoteeth-like processes inside the beak. They are easily overlooked from the distance or from other viewing directions. That´s one reason I  really enjoy looking at museum specimens, because you can often see tiny anatomical details you can rarely see in a moving and usually more distantly located living animal.

I tried to make another photo to get a shot of the keratinous cones in the upper beak:

Eurasian spoonbill(Platalea leucorodia), ornithological museum Rocca di Lonato (8)

That was part III of the weird bird beak series, which I hope to continue anytime. But I think I´ll make a break now to write the next blogpost about something different.

Veröffentlicht unter Anatomie, Vögel | Hinterlasse einen Kommentar

Weird bird beaks part II: The pseuodeteeth of the double-toothed barbet

Today´s featured bird with a weird beak is the double-toothed barbet (Lybius bidentatus), a colourful member of the African barbets, and around the size of a sparrow.

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Double-toothed barbet (Lybius bidentatus) taxidermy specimen from the Zoological Insitute Tübingen

The origin of their name is quite obvious, as their upper beaks shows some pretty big pseudotooth-like projections.

Another photo showing the whole taxidermy specimen:

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Veröffentlicht unter Anatomie, Vögel | Hinterlasse einen Kommentar

Weird bird beaks part I: Frontal shield beaks in violet turacos

This is meant as some sort of mini-series to feature some lesser known birds with weird beaks. Perhaps I will also include some birds which seem more familiar, but whose weird beak features are usually missed.

I start with the violet turaco (Musophaga violacea), a member of the diverse turaco family from tropical and subtropical Africa. In this birds the beak extends in a bulbous shape over the frontal skull area and forms a contiunous shield like structure.

Violet turaco (Musophaga violacea) at the Zoological Institute Tübingen

Violet turaco (Musophaga violacea) at the Zoological Institute Tübingen

If you take a close look, you can also see small serrations in the anterior part of the upper beak.

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Violet turaco from Wikipedia

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A tiny lindworm with huge hidden teeth and bone-armoured skin – The slow worm, largest lizard of Northern Europe

Central and Nothern Europe is not particularly rich in reptiles, and many of the native species are even quite rare and occur only quite locally restricted. In Germany for example, there are only around 13 species, among them five (or possibly six, with an obscure local population of Iberolacerta horvathi in the Northern Limestone Alps) species of lizards, six species of snakes (of which three have only very small to tiny distribution areas) and the European pond turtle Emys orbicularis, which is also nearly fully extinct here.

There is also another one, which is among my favourite native reptiles, the slow worm Anguis fragilis. Besides sand lizards and wall lizards, which are comparably common and numerous in certain areas, they are the only native reptiles I see at least moderately often, yet still only on occasion.

Slow worm Anguis fragilis

Slow worms are fascinating for many reasons. First of all, they have one of the largest geographical ranges of all reptiles, from the most southern areas of Italy up to northern areas of Sweden and Finland, only surpased by the viviparous lizard Zootoca viviparia.

Population range of Anguis fragilis from Wikipedia

One reason why they can occur even in very cold areas is probably because they are ovoviviparous, so pregnant females can follow the sun and in this way boost the growth of the embryos, even in areas with short summers.

Slow worm juvenile

Besides wall lizards, which sometimes live even right into towns (like an allochthonous population from Northern Italy which lives around the castle of Tübingen and some other areas in the town) and sometimes sand lizards, slow worms are also nearly the only native reptiles here which are sometimes living in comparably densely populated areas. I knew a population which lived (or still lives) in a housing area which had besides some small gardens and hedges next to no green areas, only one small building ground of perhaps 25 x 20 m covered with grass and blackberry.

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A slow worm I photographed in a semi-urban area at Korfu, Greece.

Slow worms are – as you might imagine form their name – not very fast. They often wiggle in a very stiff and somehow clumsy way, very unlike snakes. The reason for this is not externally visible, but becomes more evident if you touch a slow worm. They feel quite hard, because their whole body is covered by small round osteoderms, which are below the scales. This osteoderms are connected comparably tightly with each other, and can even still preserve the external shape of a dead slow worm, when all soft-tissue inside has already broken down or was eaten away by scavenging insects.

Some years ago I found a half slow worm on a sidewalk next to a garden, perhaps killed by a cat or road-killed by a bike. Some of the scales around the head were lost, and the body shape was somewhat distorted from shrinking, but it was still not very different from those of a living slow-worm, besides being fully hollow at the inside. I have also a 3D X-ray scan of this specimen made via cone beam computed tomographie, but stupidly I had the data not available on my PC when I wrote this blog entry.

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Mummified slow worm

Last year I also found a piece of a slow worm on a concrete blog at my garden parcel, possibly placed there by a cat. It had been lying there for quite a while, and it had been warm and rainy for some time, so parts of the scale-armour-like skin areas disarticulated and isolated round osteoderms became visible.

Anguis osteoderms

Close up of the osteoderms:

Slow worm osteoderms detail

When dead slow worms break down and the scales fall off, you can´t only see those cool osteoderms, but also another rather unsuspected anatomical feature, nasty teeth like tiny curved daggers. Compared to the size of the skull, those teeth are really huge, proportionally well bigger than those of komodo dragons or mosasaurs for example. But you still can´t see them in live slow worms, because they have -like all squamates – well developed lips which cover their teeth. Keep this in mind the next time you see a reconstruction of a mosasaur or Megalania with well visible teeth. That´s not realistic, they had surely like all other squamates lips which covered their teeth, so they were nearly not visible when the mouth was open, and there is no good reason to think it was different in those extinct lineages.

Another, already quite decomposed dead slow worms I found. Those teeth are really nasty.

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The other side of the head:

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Again a close up of the first mummified specimen. It´s really very very hard to get good photos of this tiny anatomical details, as the whole skull is well under a centimetre in length.

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So, for what are those sting-like teeth good for? Slow worms feed mainly on soft-bodied invertebrates like small slugs and earthworms, and the long pointed teeth help to hold slithery prey covered in mucus. I once observed a slow worm eating a huge earthworm which was nearly equal in body diametre and I was really surprised how it was slowly devoured. On occasion they also consume other small invertebrates, whereas predation on other reptiles is extremely rare. There is only a small handful of documented cases in which other reptiles were eaten, like for example small sand lizards or other small slow worms. Here is a photo of such a rare event, an adult slow worm devouring a juvenile of its own species (photo from Wikipedia):

Slow worm cannibalism (from Wikipedia)

Slow worm cannibalism (from Wikipedia)

Besides for catching slugs and worms, the long teeth are also used in comment fights between males and during the mating rituals, in which the males bite the females in the head or neck area. Another photo from Wikipedia showing this behavior:

Male slow worm biting female. You can also see very well the difference of the non-autotomized tail of the male and the shrt re-grown tail of the female on the left.

Male slow worm biting female. You can also see very well the difference of the non-autotomized tail of the male and the short regenerated tail of the female on the left.

As a result of this rigorous use of the teeth, some specimens show severe skin-scarring. The scratches on this very large dead-found slow worm are also possibly the result of intraspecific bites, yet I doubt it was the reason why it died, as the scratches are not very deep.

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Furthermore, the osteoderms should reduce most damage to superficial skin injuries, and I already wondered if this armoured skin is possibly mainly a defense against the teeth of other slow worms, and to a lesser degree a defense against predators. In sharks females have also usually a much thicker skin than males, because they are often bitten by the males while mating. I also doubt that even this tough skin armour has that much effect against most predators at all, given the very large number of animals which prey on slow worms. The teeth of hedgehogs and small carnivores are well capable to deal with this kind of armour, and it´s also no very effective defense against birds of prey, storks or other larger potential slow worm predators. Nor does it seem to help much against smooth snakes (Coronella austriaca), which are -where they occur in the same area- important predators of slow worms. This surely doesn´t mean the osteoderms have no defensive function against predators at all, but it´s possibly only one of several functions.

Autotomie however seems to play an important role in self-defense, and a large number of slow-worms have regenerated tails. Here is a photo of a freshly autotomized tail I found at my garden parcel, which was still moving at that time.

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If you take a close look you can even see the different muscles at the base of the stump:

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Another photo of a specimen which obviously lost its tail only a short time before.

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Close up of the stump. You can also see where the slow worm was grabbed by a predator:

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The species name fragilis already indicates the autotomizing behavior of slow worms. I once found a roadkilled juvenile slow worms which apparantly autotomized in death agony its tail on multiple areas.

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Most slow worms are somewhere between 25 and 35 cm, what also depends on the nature of the tail of course, as regenerated tails are often much shorter than the original tails. Some slow worms can however sometimes grow considerably larger. Several years ago I found a monstrously huge specimen during a walk in a vineyard area. It showed no external injuries, only the eyes had already dried, but it had some blood around its nostrils, what could indicate intoxication of some sort, perhaps as a result of insecticides or molluscicides used in the area. Because of its big size and unusally good condition I took it for my collection to store it in a jar with alcohol. It was already quite stiff, so I could not straighten it for a good measurement. Instead I used a piece of thread to measure over the curve of its body. I was highly surprised when I realized the thread was hardly long enough, even more so when I found it was 45 cm in length. This measurement was made quickly and I did not follow the curve of the body that exactly, what resultet in some underestimate of the length. When I later made another measurement with a longer thread and a more exact following of the curves, I came to an incredible 48 cm. That is truely huge, as long as my arm (without the hand).

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Dead monster slow worm

Here again a photo of the preserved monster specimen:

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At that size it was already bigger than every other species of lizard here, even the two species of green lizards hardly reach lengths of 40 cm, but usually stay well shorter. To be fair, their heads and bodies are still somewhat bulkier than those of slow worms. By chance there actually is a very cryptic population of green lizards in that which was just officially verified last year in the area where I also found the giant slow worm. I was quite lucky to discover one of those green lizards and take some very first photos of it.

Another large yet not giant dead-found specimen of 41,7 cm:

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Here is a specimen which is more in the upper average range, photographed several years ago with my old mobile phone I had at that time.

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I have seen some few specimens of similar sizes as the „monster“ in museum collections like at Copenhagen, Berlin and Vienna, and there are some other specimens on record which actually exceed a full half metre in length. The discovery of an extremely exceptional specimen was published in 2012 in the journal Zeitschrift für Feldherpetology (journal of field herpetology) by Wolfgang Böhme. This particular specimen had a length of 57, 5 cm, what is by the standards of its species truely gargantuan, nearly a small real-life lindworm.

I think it is somewhat erroneous to think that such outsized specimens have to be unusually old. A lot of people are under the impresseion that reptiles, fish and amphibians grow for their whole life and can therefore (theoretically) reach every size. But in reality, that´s a massive simplification to say it at least. First of all the growths of different species can differ highly. Especially many smaller species have more or less determinate growth and most adult specimens in a population have quite similar sizes, independent of age. Some species grow for a longer time and gain even after reaching sexual maturity for some time additional length, sometimes for many years. But even then, growth usually decreases considerably, and the proportional length growth in later years is normally very low or even next to absent. An exceptionally big specimen was most probably already quite big at early age when unusually strong growth had the strongest effect. Of course big size can be an advantage, for example when it is an advantages against predation, what can facilitate over-average life-spans of those specimen. But on the other hand, there will be specimens which never reach exceptionally big sizes, even after many decades.

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And slow worms can actually live for many decades. Besides certain testudines and crocodylians, slow worms have one of the longest recorded life-spans of all reptiles. They can reach an age of 46 years at least, and a specimen which was once kept in the Copenhagen Zoo was said to have lived there for 54 years.

Another little known fact about slow worms is that they can be surprisingly colourful. In general they are of mainly greyish, coppery or brownish colour, sometimes with some patterns in the head and neck area, which his often more pronounced in juveniles. Especially juveniles have also often a dark dorsal stripe and often a more marked colour difference between dorsal and ventral sides.

That´s another dead slow worm I found (still fully flexible and without any injuries, possibly another one which died from intoxination):

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Note the compass with included ruler, this little gadgets are extremely handy and useful to take photos with size comparisons.

The ventral side in this specimen was nearly fully jet-black, what´s also not that common:

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But some specimens have also bright blue scales as well. The amount of those blue scales can vary significiantly, sometimes there are only some few and isolated ones, sometimes the spots are all around. I´ve seen so far only two specimens with pronounced blue scales, one of them was a roadkilled specimen which I fond only a few metres next to the monster specimen.

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Population screenings in Northern Italy showed that only lesser than 0,8% of the whole slow worm population possess those blue scales, which are usually mainly found in older males. In the related Anguis colchica they are more common, with blue scales occuring even among females, and there is even a specimen on record which had a fully blue belly.

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Juvenile specimen with marked colour contrast between lateral and dorsal area.

I wrote this blog-post especially for those non-European readers who aren´t familiar with slow worms, but also of course for all other people which have slow-worms around. The next time you see one, keep in mind how awesome and fascinating this little lindworms are.

Veröffentlicht unter Naturbeobachtungen, Reptilien | 2 Kommentare

The war boar of Dáin Ironfoot – a zoological easter egg in The Hobbit: The Battle of the Five Armies

This post is a novel one, as it´s the first one written in (probably bad) English. So far all posts I wrote within the last 8 years on my blog were only in German, but I will give it a try to make at least on occasion also blog entries in English, especially when they deal with topics which could be interesting for a bigger audience. I hope I won´t do too many typos, misspellings and grammar errors, but I am sure that this will still happen.

I´ve been a very big Tolkien fan for decades, and „The Hobbit“ in particular is still among my all time favourite books. But I wasn´t really happy about the three movie adaptions by Peter Jackson, not only because they were full of ridiculous stunt scenes, totally senseless changes of the storyline and certain characters, but also because many of the designs just looked unfitting to say it at least. Especially the orcs in „The Hobbit: The Battle of the Five Armies“ looked simply awful, and many things in the movie looked much more like something from the Warhammer tabletop univerae than from Middle-earth.

There was however one case of artistic freedom which I really enjoyed, the monstrous war boar ridden by Dáin II Ironfoot. In the original book the dwarves have no riding animals at all, besides the ponies of Thorin and his entourage. But this coarse boar on which Dáin rides into battle was really a cool idea, because it was not simply the usual outsized wild boar which is often seen in certain fantasy worlds, but a really beefed up kunekune pig.

That´s especially funny, as this is a  rather small breed of quite docile nature. Kunekune pigs are among the smallest domestic pig breeds and are usually only between 70 and 100 kg in weight. They probably date back to pigs brought by whalers or traders in the early 19th century from Asia to New Zealand and share similarities with the better known pot-bellied pigs and are different from the long-snouted and still comparably wild boar-alike pigs from Oceania. Like pot-bellied pigs they have a very short and domed head with a quite short snout and short legs. Kunekunes are also quite variable in colouration and pattern, and can have all mixes of white, black, yellowish, brownish and orange.

Here is a photo of a black and whitish kunekune similar to the one ridden by Dáin:

Kunekune pig (source: Wikipedia)

Kunekunes were nearly extinct in the 1980ies, with only 50 remaining pure bred specimens. Luckily this unique pigs were saved from extinction by the attempts of breeders, so there are now again several thousands of them. Since some time there is also a pair at Wilhelma Zoo Stuttgart, where I have seen them for the very first time in real life.

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Kunekune Wilhelma Zoo Stuttgart

Kunekune have also another special trait which is otherwise rare in pigs, a pair of tassels in the throat area, which are called piri piri by the maori. You can see them somewhat better on this photo:

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Kunekune Wilhelma Zoo Stuttgart

Besides the mounted boar the likewise fictional Megaloceros ridden by Thranduil in the movie was also a really nice idea.

This was also not the first time that the designers of Weta Workshop included elements of New Zealand´s fauna into movies. The winged „fellbeast“ ridden by the Nazgûls in the Lord of the Rings-Movies had a nearly invisible anatomical detail borrowed from the New Zealand lesser short-tailed bat (Mystacina tuberculata). Among all extant bats (the similar but somewhat bigger species Mystacina robusta became sadly extinct some decades ago), the lesser short-tailed bat is the most terrestrial one, which spends a lot of time walking, hunting and even burrowing in leaf litter on the ground. Probably as an adaption for this terrestrial way of life, their claws have a unique small extra-talon at the base of each wing and foot claw, what was also inherrited for the fellbeasts in the movies.

Veröffentlicht unter Blogposts in English, Säugetiere | Hinterlasse einen Kommentar

Paranogmius doederleini – ein unbekannter Riesenfisch aus der Bahariya-Formation Ägyptens

Die Bahariya-Formation Ägyptens ist vor allem durch einen ihrer einstmals größten und heutzutage wohl kontroversesten Bewohner bekannt, den riesigen und äußerst bizarren Spinosaurus. Dabei hatte dieses prähistorische Ökosystem eine ganze Menagerie von unglaublichen und vielfach nicht minder wunderlichen Arten zu bieten. Neben verschiedenen anderen großen bis sehr großen Arten, wie etwa gigantische Lungenfischen, Arapaima-großen Flösselhechten und gewaltigen Quastenflossern  lebten in den dortigen Gewässern auch Fische die keinerlei lebende Verwandte mehr haben. Etwa die Tselfatiiformes, eine einstmals außerordentlich erfolgreiche und vielgestaltige Ordnung innerhalb der Knochenfische.

Auch unter ihnen fanden sich einige Riesen, wie Paranogmius doederleini, dessen enorme Wirbel im frühen 20. Jahrhundert in der Bahariya-Formation gefunden wurden. Leider wurden aber keine weiteren Teile des Skeletts gefunden, und auch die von Ernst Stromer beschriebenen Wirbel sind mit vielen anderen der damals ausgegrabenen Fossilien während eines Bombenangriffs im Zweiten Weltkrieg zerstört worden.

Glücklicherweiswe hat man von der verwandten, und möglicherweise sogar mit Paranogmius identischen Art Concavotectum moroccensis einige sehr gut erhaltene Fossilien gefunden. Der außerordentlich komplett erhaltene Schädel zeigt auch gut die ungewöhnliche Kopfform dieser Fische. Joschua Knüppe hat basierend auf diesen Fossilien eine wunderbare Lebendrekonstruktionszeichnung von Paranogmius angefertigt.

 

 

Paranogmius doederleini

Paranogmius doederleini von Joschua Knüppe

Joschua hat ihn hier mit einer Länge von 3,5 m dargestellt, was der Größe von Concavotectum entspricht, wobei die von Ernst Stromer beschriebenen Wirbel sogar noch eher auf 4 m große Exemplare hindeuteten. Damit entsprachen diese Fische in ihrer Größe in etwa einem Roten Thun (Thunnus thynnus), einem der größten rezenten Knochenfische überhaupt.

Veröffentlicht unter Fische, Megafische, Paläontologie | 10 Kommentare

Der Neuguinea-Flossenfuß, eine echsenfressende Pseudoschlange unter den Geckoartigen

Weiter geht es mit einem wenig bekannten, aber dafür umso interessanteren Reptil, dem Neuguinea-Flossenfuß (Lialis burtonis). Flossenfüße kommen ausschließlich auf Australien und Tasmanien, sowie mit zwei Arten vertreten auch in Neuguinea vor. Sie zeichnen sich durch eine sehr langgezogene schlangenartige Gestalt aus, wobei die Vorderextremitäten völlig zurückgebildet, und die Hinterbeine lediglich noch in Form kleiner flossen-oder paddelförmiger Strukturen erhalten sind. Trotz dieser recht extremen Modifizierung des normalen Echsen-Bauplans sind die Flossenfüße nahe mit den Geckos verwandt, und stehen innerhalb der Geckoartigen (Gekkota) den Doppelfingergeckos (Diplodactylidae) Australiens, Neuseelands und Neukaledoniens am nächsten.

Einige Arten haben ungeachtet des schlangenartigen Körper noch Köpfe die sehr an normale Geckos erinnern, andere hingegen haben hochmodifizierte Schädelformen entwickelt, welche praktisch keine Verbindung mehr zu ihrer vierbeinigen Verwandtschaft erahnen lässt.

Einer der am stärksten spezialisierten Flossenfüße ist der Neuguinea-Flossenfuß, welcher übrigens ungeachtet seines Namens auch den Großteil Australiens besiedelt. Im Reptilienhaus des Zoos Hellabrunn in München hatte ich vor etwa drei Jahren die Gelegenheit diese hochinteressante Art einmal in natura zu sehen:

Neuguinea-Flossenfuß Lialis jicari (1)

Neuguinea-Flossenfuß (Lialis jicari) im Zoo Hellabrunn München

Mit Längen bis zu 75 cm ist der Neuguinea-Flossenfuß vergleichsweise riesig, und länger als jeder Gecko, inklusive des vermutlich ausgestorbenen circa 60 cm langen Delcourt´s Riesengecko Hoplodactylus delcourti, wenngleich natürlich auch nicht ganz so massig wie die größten echten Geckos. Wie enorm lang der Neuguinea-Flossenfuß ist, kann man hier ganz gut sehen, wobei – im Gegensatz zu Schlangen- der Schwanz um ein vielfaches Länger ist als der eigentliche Körper:

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Neuguinea-Flossenfuß (Lialis burtonis) im Zoo Hellabrunn

Das andere im Terrarium gehaltene Exemplar (auch gut unterscheidbar an der anderen Färbung) war erheblich kürzer, vermutlich hat es irgendwann einmal seinen Schwanz eingebüßt, welcher dann nicht mehr vollständig nachgewachsen ist.

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Neuguinea-Flossenfuß (Lialis burtonis) im Zoo Hellabrunn

Der Neuguinea-Flossenfuß ist ein hochspezialisierter Echsenfresser, welcher sich vor allem von kleinen Skinken ernährt, wobei in seltenen Fällen auch andere Flossenfüße, Agamen, Geckos und sogar kleine Schlangen erbeutet werden. Als Anpassung an diese Beutetiere haben sie sehr lange schmale Kiefer, wobei die Knochen an verschiedenen Stellen des Schädels flexibel miteinander verbunden sind, und im hinteren Kieferbereich selbst bei komplett geschlossenem Maul noch eine weiten Abstand voneinander haben, so dass sie ihre Beutetiere wie mit einer Beißzange umschließen können. In dieser Position halten sie ihre Beute teilweise über eine Stunde lang fest, bis sie gefahrlos verschlungen werden kann. Dabei helfen auch die spitzen, nach hinten gekrümmten und leicht beweglichen Zähne die Beutetiere festzuhalten und am Entkommen zu hindern.

Neuguinea-Flossenfuß (Lialis burtonis) im Zoo Hellabrunn

Eine weitere Besonderheit ist die Art des Beuteerwerbs. Neuguinea-Flossenfüße gehören zu den wenigen Reptilien die, zumindest gelegentlich, Beutetiere mit Bewegungen ihres Schanzes anlocken. Dies geschieht vor allem dann wenn ein potentielles Beutetier beim ersten Angriff nicht sofort erwischt wurde, oder wenn der Flossenfuß schon länger nichts mehr gefressen hat.

Werden Neuguinea-Flossenfüße selbst angegriffen, haben sie die Möglichkeit zu versuchen sich durch Autotomie zu retten und ihren Schwanz abzuwerfen. Bevor sie eine derartig drastische Rettungsmaßnahme in Betracht ziehen, geben sie aber erst einmal Geräusche ab um potentielle Angreifer zu verwirren und abzuschrecken, übrigens ebenfalls ein Verhalten das sich bei vielen Geckos findet.

Eine weitere Gemeinsamkeit welche die nahe Verwandtschaft zu den Geckos nahe legt zeigt sich bei der Fortpflanzung. Genau wie Geckos haben Flossenfüße üblicherweise aus nur zwei Eiern bestehenden Gelege, wobei nicht selten mehrere Weibchen die gleichen Ei-Ablagestellen benutzen, so dass sich teilweise bis zu 20 Eier zusammen finden.

Hier sieht man noch einmal ein Detailphoto einer der beiden kleinen Hinter-„Flossen“:

Neuguinea-Flossenfuß (2)

Neuguinea-Flossenfuß (Lialis burtonis) Hinterextremität

Die Anzahl der ungewöhnlichen Verhaltensweisen oder seltsamer anatomischer Begebenheiten bei Flossenfüßen ist damit aber noch lange nicht abgedeckt. So verbleibt noch weitere Gelegenheit diese vielleicht irgendwann einmal in einem Beitrag über die zweite Unterfamilie innerhalb der Flossenfüße auszuführen, den Pygopodinae.

Veröffentlicht unter Reptilien | 2 Kommentare

Obskure Reptilien Teil 1: Die Rote Doppelschleiche

Unter den beinahe 10.000 bekannten lebenden Arten von Schuppenkriechtieren finden sich zahllose hochspezialisierte und im Allgemeinen kaum bekannte Linien, welche teilweise deutlich von der typischen Echsengestalt abweichen. Eine dieser Linien sind die Doppelschleichen (Amphibaenia), welche sich in recht extremer Weise an eine grabende Lebensweise angepasst haben. Mit Ausnahmen der Handwühlen haben alle Doppelschleichen keine äußeren Gliedmaßen mehr, dafür einen sehr stark verknöcherten massiven Schädel, verkümmerte Augen, assymmetrische Lungenflügel und segmentiert angeordnete kleine und besonders glatte Schuppen, alles Anpassungen an eine Fortbewegung im Boden.

Die meisten Arten sind recht klein und schlank, wobei die Rote Handwühle (Amphisbaena alba) mit Maximallängen von über 70 cm und einem sehr kompakten Körper eine recht respektable Größe erreicht.

Rote Doppelschleiche (Amphisbaena alba) Quelle Wikipedia

Rote Doppelschleiche (Amphisbaena alba)
Quelle Wikipedia

Die in Südamerika heimische Rote Handwühle ernährt sich vor allem von Insekten und legt auch häufig ihre Eier in die Nester staatenbildender Insekten wie Termiten und Ameisen, welche ebenfalls zu ihrer Hauptnahrung gehören.

Rote Doppelschleiche (Amphisbaena alba) Quelle Wikipedia

Rote Doppelschleiche (Amphisbaena alba)
Quelle Wikipedia

Rote Handwühlen können im Gegensatz zu vielen anderen Squamaten nicht mehr ihren Schwanz abwerfen, dafür ist ihr kurzer dicker Schwanz mit zähen Bündeln aus Kollagenfasern verstärkt. Fühlen sie sich angegriffen, recken sie ihren Schanz in die Höhe um dadurch von ihrem Kopf abzulenken

Veröffentlicht unter Bild des Tages, Reptilien | 2 Kommentare

Bild des Tages: Chinesischer Riesensalamander

Nach dem kleinen Bergmolch kommt jetzt ein ganz besonders großes Amphibium, ein Chinesischer Riesensalamander (Andrias davidianus) aus dem Vivarium des Naturkundemuseums Karlsruhe:

Chinesicher Riesensalamander Karlo im Vivarium Karlsruhe

Bei diesem Exemplar handelt es sich um Karlo, welcher auch das offizielle Maskottchen des Museums ist. Karlo ist inzwischen 37 Jahre alt, und etwa 1,5 m groß, womit er der größte Vertreter seiner Art in Deutschland ist.

Man sieht auf dem Photo auch ganz gut die beiden Erhebungen oben auf dem Kopf. Dabei handelt es sich um die gewaltigen Kiefermuskeln, welche es Riesensalamandern ermöglichen ziemlich kräftig zuzubeißen. Sie sind auch ein recht gutes Beispiel dafür dass gerade bei Amphibien die Form des Schädels sich auch recht deutlich vom lebenden Tier unterscheiden kann. Nicht nur durch die enormen Kiefermuskeln, sondern auch durch die fleischigen Lippen, welche die kleinen scharfen Zähne komplett verdecken. Selbst wenn man lebende Amphibien nicht in jeder Hinsicht mit ausgestorbenen Linien wie den Labyrinthodontiern vergleichen kann, sollte dies dennoch bei der Rekonstruktion bedacht werden. Eine ganze Reihe fossiler Amphibien etwa wurde fast mit Sicherheit viel zu „zahnig“ rekonstruiert.

Als Vergleich hier noch mal der Schädel eines Japanischen Riesensalamanders (Andrias japonicus) aus dem Zoologischen Schausammlung Heidelberg:

Japanischer Riesensalamander Schädel

Veröffentlicht unter Amphibien | 5 Kommentare