Month: March 2024

Kermitops

Despite being named after the famous Muppet frog, Kermitops gratus here wasn’t actually a frog itself. Instead it was a close relative of the common ancestor of all modern amphibians, part of a grouping of amphibian-like animals known as amphibamiform temnospondyls.

Living in what is now Texas, USA, during the mid-Permian, about 275 million years ago, Kermitops would have resembled a chunky salamander. Only its fossil skull is known, so its full body size is uncertain, but based on the proportions of related amphibamiformes it was probably around 15-20cm long (~6-8″).

Although its discovery helps to fill in the very sparse fossil record of the early evolution of modern amphibians, it’s also complicated matters more than expected. Previously it was thought that the characteristic skull anatomy of modern amphibians evolved in a clear sequence, but Kermitops has a unique mix of features that doesn’t fit this idea – suggesting that there was a lot of convergent evolution going on in amphibamiformes at the time.

Eurotamandua

Eurotamandua joresi lived during the mid-Eocene, about 47 million years ago, in the lush subtropical forests that covered what is now central Germany.

When it was first described in the early 1980s it was classified as an anteater due to its close resemblance to some modern species… but there were big problems with this interpretation. Anteaters have a sparse fossil record, but they’re known to have originated during the early Eocene in the isolated island continent of South America – so Eurotamandua’s ancestors making it all the way to Europe within just a few million years would be pretty remarkable!

Also, on closer inspection it didn’t have the distinctive skeletal features of a xenarthran mammal, suggesting it wasn’t an anteater after all.

Instead more recent studies have identified it as a close relative of pangolins, part of an early branch of the group that didn’t have the characteristic large scales.

About 90cm long (~3′), Eurotamandua would have a lifestyle much like the anteaters it convergently resembled, using its large claws to rip open ant nests and a long sticky tongue to feed.

Dinocephalosaurus

Dinocephalosaurus orientalis was a fully aquatic protorosaur reptile living in what is now southwest China during the mid-Triassic, about 244 million years ago.

Up to 6m long (~19’8″), it had a long serpentine body with paddle-like limbs and an especially elongated neck – but despite the superficial similarities to its semi-aquatic cousin Tanystropheus, Dinocephalosaurus’ long neck appears to have been independently evolved.

Much like the similarly-shaped elasmosaurs, its neck may have had a “stealth” function, allowing it to bring its jaws closer to targets before the rest of its body was visible, then using side-to-side snapping bites to catch its prey in its interlocking “fish-trap” teeth.

A preserved well-developed embryo inside one specimen also suggests that Dinocephalosaurus gave birth to live young, making it one of only two archosauromorph lineages known to have ever evolved this reproductive strategy.

Hemingwaya

Hemingwaya sarissa here was one of the earliest known billfish, related to modern sailfish and marlin. Living during the late Paleocene, about 58 million years ago, it inhabited the area around what is now Turkmenistan, in the warm shallow waters of the western Tethys Sea that covered much of central Asia at the time.

It was rather small compared to its modern relatives, just 30-40cm in length (~1′-1’4″), with a long streamlined body armored with six rows of scutes. Its slender snout was lined with tiny teeth, and both its first dorsal fin and first anal fin were tall and elongated. 

It probably wasn’t a very active swimmer, instead hovering near the surface and catching smaller prey with quick bursts of speed.