Professor discovers ancient species of crocodile

Students assisting in the excavation process.


A new species of ancient crocodilian was recently categorized and named, Deltasuchus motherali, by the Arlington Archosaur Site Team (AAS) located in Arlington, Texas. This research was started in 2008 by Dr. Derek Main working from the University of Texas Arlington. Dr. Chris Noto, a paleontologist from UW-Parkside, took over the site after Main’s passing in 2013, where he has been continuing work on the site since.

Archosaurs refer to a group of dinosaurs’ who would be relatives to modern day crocodilians and many bird species, dating back between 95-100 million years ago, included in these dinosaurs would be Tyrannosaurus Rex and Triceratops. This discovery and classifying of this croc is significant because of the specific time in the fossil record it gives a look into.


The Discovery

Deltasuchus motherali is approximated to have been 20 feet in length, and based upon fossilized bones of its former prey, the croc consumed almost anything it wanted to within its habitat. This, Dr. Noto explained, “was an aquatic ambush predator like most crocs today…but instead of wildebeests it was grabbing duckbilled dinosaurs…and was definitely the top predator in its ecosystem.” This specimen is important because it is a new and unique species of Archosaur, but it also acts as better insight into the Middle Cretaceous period, a time on Earth where little is known about how animals evolved and lived. Dr. Noto explains that the classifying of this specific species of croc is significant because “it’s not related to any crocodiles or alligators today, it’s part of an extinct lineage, despite superficially resembling modern crocodilian.”


Not like any other Croc

As Dr. Noto explained, this species of croc does not have any living relatives today, despite its striking resemblance; therefore, Noto refers to the species as a “croc cousin”.  The methods, researching, and cataloguing of every little and big piece of bone is critical to placing the animal into a known lineage. When deciding where to place a species, paleontologists compare features of fossils from other similar species using computer software to locate the best lineage the features of those fossils fit in. Using this technology and the many hours of hard work from students and faculty sorting through the fossils, Noto and the AAS team was able to distinguish Deltasuchus motherali as a new and unique species.


Student involvement

Over the years many students have been involved in the sorting, cleaning, and cataloguing the different specimens recovered.  Currently, Dr. Noto is working with students who are screen washing sediment recovered on the site to obtain the smallest of specimens in the site. Through a series of sieves, students sort through sediment to find larger pieces to be dried in an oven and examined through microscope after. The work from students has recovered a mass of specimens from the dried sediment which gives a very clear look into how the ecosystem functioned as a whole.

Dr. Noto expresses his excitement for the future of the site in saying, “this is a period of time [where] we don’t really have much of a fossil record, which gives the potential for things we find to be brand new.” In addition to students working on UW-Parkside’s campus, many students have also cleaned specimens at the Kenosha Dinosaur Discovery Museum through a partnership with Carthage College. Furthermore, since 2011, two students have actually been able to travel to Arlington and take part actual excavation. Dr. Noto asserts the importance of student involvement with this project going on to say,  “every part of the work, no matter how seemingly mundane, you have to do the cleaning and do the sorting, hundreds of hours of work, but every bit of it is absolutely critical.”


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