Four Temnospondyls

“Four Temnospondyls”
Coloured pencil illustration
August 2008

Top left:
Eryops megacephalus Cope, 1877
Eryopidae; Temnospondyli; Amphibia; Chordata
Early Permian North America

Top right:
Mastodonsaurus giganteus (Jaeger, 1828)
Mastodonsauridae; Temnospondyli; Amphibia; Chordata
Mid-Triassic Germany

Bottom left:
Platyhystrix rugosus (Case, 1910)
Dissorophidae; Temnospondyli; Amphibia; Chordata
Early Permian North America

Bottom right:
Gerrothorax pulcherrimus (Fraas, 1913)
Plagiosauridae; Temnospondyli; Amphibia; Chordata
Late Triassic Germany

Photo:
Paracyclotosaurus davidi Watson, 1958
Capitosauridae; Temnospondyli; Amphibia; Chordata
Triassic Australia (and other parts of Gondwana)
Natural History Museum, London
March 2008

While the folks are all watching Eastenders, I thought I’d pop upstairs and do a quick blog post. I like temnospondyls, they are a group of amphibians long extinct that left no living descendants. The group containing all living frogs, toads, newts, salamanders and caecilians is the Lissamphibia. Temnospondyls are generally differentiated from the other amphibians by their vertebrae (the name “temnospondyl” itself is Greek for “cut vertebra”), but not all temnospondyls share this feature.

Eryops megacephalus (“big-headed, drawn-out face”) was up to 2 m (6’) long (much bigger than any axolotl I’ve seen). Mastodonsaurus giganteus (“giant nipple-toothed lizard”) was slightly smaller but looked more crocodilian than Eryops. Platyhystrix rugosus (“rough flat porcupine”) looks like an amphibian analogue of Dimetrodon or Edaphosaurus, the therapsids like those that gave rise to all mammals. If the sail served a similar function, it would be the only amphibian we know of to have the ability to thermoregulate! Gerrothorax pulcherrimus (“very pretty wicker chest”... where do these names come from?!) looks like a lemon-headed axolotl. It is known for its inability to open its lower jaw, so instead, it raises its skull when it wants to eat, like a dustbin lid.

I purposefully chose bright colours for all these temnospondyls, but the colours for Gerrothorax were particularly inspired by Stewie Griffin of Family Guy... the shape of the head reminded me too much of him so I gave it red dungarees to match its gills.

Hope you’re having/had a good Xmas, I didn’t even eat that much (yet) and I’ve been feeling queasy.