About armoured snakes
When we mention bony plates found in the skin of vertebrates, you probably think of armoured prehistoric dinosaurs. However, it now appears that such structures are also common in large reptiles – Squamata. Nevertheless, they have never been described in snakes. Since this group is very diversified, a team of experts led by Petra Frýdlová and Daniel Frynta from the Department of Zoology at the Faculty of Science, Charles University decided to focus on this group
Bony formations embedded in the skin - so-called osteoderms - are relatively common in adulthood in many vertebrate species. Remarkably little is still known about their development and function. Because of their superficial location, it is thought that they probably serve mainly for defence. However, they could also have other functions, for example, they may help with locomotion, thermoregulation or calcium storage. The absence of osteoderms in snakes is often attributed to the fact that the presence of surface armour would greatly reduce their agility and movement speed. On the other hand, in the legless Slow worm lizard (Anguis fragilis) or European legless lizard (Pseudopus apodus), osteoderms do not appear to significantly limit their rapid movement.
The team of experts therefore focused on searching for osteoderms in a total of 68 specimens belonging to 27 snake species from different families. The great advantage was that imaging technologies have advanced a lot in the last decade, allowing for a simpler and, more importantly, non-invasive study of the specimens. Scanning by micro-computed tomography (μCT) was carried out in collaboration with the Institute of Experimental and Applied Physics, Czech Technical University in Prague.
Source: Petra Frýdlová and Jan Dudák.
The search has been successful. Scientists have detected osteoderms in a total of four species of sand boas of the Eryx genus. They were found in adults, mainly on the tail and on the body about 4 cm anterior to the cloaca. Their pattern followed a fairly regular distribution of scales. The possible protective function of osteoderms in sand boas is supported by the fact that these snakes live partly underground and have enlarged and highly modified caudal vertebrae that almost completely fill the volume of the tail. This part of the body thus appears to be under strong predation pressure. The authors liken these structures to medieval armour and interpret them as a part of a rich passive defensive strategy of the sand boas.
Petra Frýdlová, Kateřina Fraindová
Published:
Jan 23, 2024 09:05 AM
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