Koolasuchus cleelandi was approximately 5 m (16 ft) long and 500 kg (1100 lbs). The large temnospondyl had an enormous head measuring about 65 cm (26 in) from snout to occiput. That head has been described a number o different ways, but it is most commonly depicted as possessing caudal facing lateral horns or as possessing a completely rounded head, like most modern salamanders. That enormous head was common in the Cretaceous rift valleys of Australia within the Arctic Circle. At that time Koolasuchus and its environment was subject to the long dark seasons of the extreme southern end of Earth. Koolasuchus and the dinosaurs it lived with were well adapted for these seasonal changes in different way. Though a hypothetical situation has been posed for this environment, the hibernation of Koolasuchus is based on similar cycles of extant salamanders. The fast moving streams in which Koolasuchus lived were ideal for crocodilian type predators, as Koolasuchus was hypothesized to have been. Unfortunately, its crocodile-like habits most likely led to its displacement and extinction as crocodilians, better at being crocodilians, took over their waterways and out competed Koolasuchus, replacing it in younger geographic strata.
17 January 2017
Temnospondyls have not been discussed much here, as a group. Therefore, we do not have a vast library of literature concerning them that I can point back at and say "remember when we read such and such" making papers regarding Koolasuchus cleelandi that much more unique and special for us this week. One of the problems of Koolasuchus being a largely ignored taxon though is that there is not a lot of literature to fall back on. There are plenty of papers that mention or compare the animal to other closely related animals, but few that investigate the biology or history of Koolasuchus itself. The remains of Koolasuchus are actually fairly substantial (portions of the mandible plus an assortment of post-cranial elements) compared to many fossils and lacking elements cannot be blamed in this instance. Subsequent discoveries of Koolasuchus fossils have added even more material to the known animal, further alleviating lack of information issues. However, given that the papers linked above refer to Koolasuchus but are not entirely dedicated to the temnospondyl, the paper to read this week for the most information on the animal is the description paper of Warren, et al. 1997 that describes the discovered elements in detail. An extensive paper, the anatomy is discussed at length and placement of the animal is also discussed, though Warren and Marsicano 1999 reexamines the phylogeny of Brachyopoidea which discusses the placement of Koolasuchus and many other temnospondyls.
16 January 2017
Koolasuchus appears in one Walking with Dinosaurs episode and in no other documentaries, movies, or cartoons. It is kind of a dud in terms of animation/CGI. Koolasuchus is not the problem though, public interest and knowledge prior to the inclusion of the large temnospondyl in this episode. Koolasuchus figures into the episode significantly and it was well received in the episode. Enjoy this short clip of the temnospondyl trudging about the Antarctic forest (ignore the title please):
15 January 2017
14 January 2017
The Cretaceous amphibian Koolasuchus was not at all a suchian (crocodilian) but it was fairly cool; though it was named for Lesley Kool, not because it was interesting. Evoking the very image of the modern salamanders, Koolasuchus was a member of the temnospondyl group; a large group of tetrapods often considered the most primitive amphibians. Tenospondyls were often mostly aquatic and, while this does not entirely separate them from modern amphibians (think of all f the entirely aquatic amphibians that are still around us today), it was a defining characteristic of many temnospondyls. What does an "entirely aquatic" fossil animal look like though? In the case of Koolsuchus that body type is dorsoventrally flattened and very salamander-like. What I mean by that term is an elongate, smoothed body with somewhat shortened limbs and a tail that, in some instances, is mediolaterally thin and dorsoventrally wide; this aids the salamander in swimming around its environment. Salamanders that are not as aquatic, including some newts, have more conical tails. As we said previously, Koolasuchus was an aquatic animal, making the thin tall tail more realistic.
|©Peter Trusler for Museum Victoria of Australia|
13 January 2017
Matt Martyniuk's Sapeornis looks a bit like a hawk or a falcon. Jeff Powers also went with that look for Sapeornis. The exact look of the bird is actually unknown, but that is a good start. Many other illustrations have shown the bird as a sparrow-esque or corvid-like (think ravens and crows) animal. Regardless of how the bird is envisioned, artists have done wonderful things with the look of the bird. Not all of the illustrations are magnificently and brilliantly colored, but as of yet we do not know what the coloration of Sapeornis may have been. Michael Rothman's illustration is one of those that is less colorful; however, it is still a beautiful piece and it exhibits an amazing representation of the tail feathers that were discussed the other day.
12 January 2017
Sapeornis is named after the Society of Avian Paleontology and Evolution (SAPE), but what is that exactly? SAPE is an organization of scientists devoted to researching the origins and adaptations of birds from the Mesozoic to the modern era. The group is actually somewhat small, by typical scientific society standards, but is populated by an eager and able group of researchers. Their dedication to describing and discovering fossil birds and their course through history has earned the society a great deal of notice in scientific circles and their achievements were rightfully honored with the naming of Sapeornis. This is not the only claim to fame or public notoriety associated with the bird, however. Despite the dearth of movies, documentaries, and gaming references (very typical outlets for dinosaurs and other fossil animals in the public domain), Sapeornis is a fairly well-known fossil animal. Unfortunately, it is often lumped into lists of fossil birds, which is how it is well-known by the public. It is an average sized bird, by today's standards, which is interesting, but does not make it terribly popular by any means.