Eiectus

Credit: Fabio Alejandro.

*Eiectus* is an extinct genus of brachauchenine pliosaur that lived in Australia during the Early Cretaceous.

## History

Andrew Crombie (1899) discovered a fragment with 6 teeth and donated it to the Queensland Museum where Heber Longman (1924) would name it *Kronosaurus queenslandicus*. A partial skull was later discovered in 1929 in the same locality. A controversial 2021 paper would move all remains except for the (deemed "nondiagnostic") holotype into a new genus, *Eiectus*. This was met with backlash, especially as *K. queenslandicus* would then only contain the holotype and no other remains. The authors admit that specimens from the Albian may represent a new genus, which would leave Aptian *Eiectus* as valid and would leave an excuse for *Kronosaurus* to be conserved. Welles (1962) suggested that *Kronosaurus* should use the Harvard specimen as a neotype..

## Description

The first 3 maxillary teeth are enlarged and form caniniform "fangs", with 3 pairs of similar caniniform teeth in the mandible directly in front of the fang-like top teeth. The lower jaw caniniforms stop between the last pair of premaxillary teeth and the first pair of maxillary teeth. This forms a diastema. 4 pairs of premaxillary teeth are found, with enlargement of 2 pairs of mandibular teeth may indicate why a 5th pair is not present. Their teeth are over 7 inches long (with the largest 30 centimeters long with 12 centimeter crowns), lack carinae and distinct trihedral in *Pliosaurus* and *Liopleurodon* and are conical. These features have allowed for easy referral of Australian specimens.

## Paleobiology

*Eiectus* specimens are known to preserve turtles and plesiosaurs as gut contents, which shows that they were prey for the large pliosaur. Large squids are also found in the area, so it has been hypothesized that they too were prey items, though there is no direct evidence for this. *Eromangasaurus* bears large, round bites on the skull that may have been due to *Eiectus* predation. *Eiectus* lived in the Australian Toolebuc and Wallumbilla Formations (Aptian-Late Albian).

## Notable Specimens

* "Plasterosaurus": This specimen was discovered in a 1931 expedition by the Harvard Museum of Comparative Zoology. It is known as the Harvard Australian Expedition (1931-32), containing Prof. William Morton Wheeler, Dr. P. Jackson Darlington Jr., Dr. Glover Morrill Allen and student Ralph Nicholson Ellis, medical officer Dr. Ira M. Dixon and William E. Schevill. This was a very successful expedition that recovered many Australian fossils. One of these includes limestone nodules with a near-complete skeleton sticking out of them that was made known by R.W.H. Thomas, a rancher, who had found it on his property in Hughenden. These were blown out of the ground into chunks up to 4 tons with dynamite, where Schevill shipped them back to Harvard where the skull was prepared immediately . However, the remaining skeleton was ignored for 20 years due to budget restrictions. This specimen is near identical to the holotype of *K. queenslandicus*. The rest of the skeleton was eventually prepared out in 1959 due to a donation of over ~10,000 from philanthropist Godfrey Lowell Cabot. This also allowed for plaster casts to be made. These appear to have been restored with too many vertebrae, which has caused for great overestimations in size (12.8 meters) when the actual animal was likely around 9-10.9 meters long. This has also caused for confusion as to what is original bone and what is plaster in the resorted specimen, earning the nickname "plasterosaurus".

## References

1. ↑ https://paleobiodb.org/classic/basicTaxonInfo?taxon\_no=100125
2. ↑ 2.0 2.1 2.2 2.3 https://en.wikipedia.org/wiki/Kronosaurus
3. ↑ https://www.sciencedirect.com/science/article/abs/pii/S0195667121003700?via%3Dihub#
4. ↑ https://twitter.com/TetZoo/status/1473053638075596812
5. ↑ Welles, S. P., 1962, A new Species of Elasmosaur from the Aptian of Colombia and a review of the Cretaceous Plesiosaurs. *University of California Publications Bulletin Department of Geological Sciences* **44**: 1-89
6. ↑ https://www.thecrimson.com/article/2019/11/7/kronostory/