SVP 24 – Last abstract and a note by Holtz on the DML

Li et al. 2015
present a new thalattosaur specimen, complete and preserved in ventral view.

Figure 1. New Xinpusaurus described by Li et al. 2015.

Figure 1. New Xinpusaurus described by Li et al. 2015.

From the abstract
During the excavation in the Wusha District, Xingyi City, Guizhou Province from 2010 to 2013, a new thalattosaur specimen was excavated from fossil bed 53 of the Upper Assemblage of the Xingyi Fauna, where abundant marine reptiles, fishes and invertebrates are found. This new specimen represents a new species of the thalattosauroid Xinpusaurus. The skeleton is nearly complete and articulated, with only some caudal vertebrae missing. Its total length is about 2.1 m. The skull is preserved in ventral view, with a length of more than 40 cm. This specimen is ascribed to the genus Xinpusaurus based on the dorsally curved anterior end of maxilla, and a proximal end of the humerus that is wider than the distal end. It differs from the type species Xinpusaurus suni by several features. The posterior process of its jugal is undeveloped, while other thalattosaurs all possess triradiate jugals with an elongate posterior process. The coracoid is oval, different than the arch-shaped coracoid of X. suni. The radius is relatively short, only about half the length of the humerus, whereas in all specimens of X. suni, the length ratio of the radius to humerus is more than 0.63. The constriction of the femur at mid-shaft is unremarkable, which is quite unique in Thalattosauria. In addition, the posterior part of the iliac blade is rectangular without a pointed tip, an element that has not yet been described for X. suni. 

I think the authors did a good job here.

On a side note…
Dr. Thomas Holtz (Dept. of Geology, University of Maryland)

reported this bit of wisdom on the Dinosaur Mailing List regarding a previously published specimen that was later redescribed as a chimaera (mix of several specimens).

“It happens sometimes. Your search image is off, and you misconstrue one element for another similar-shaped one. For instance, a bone identified originally as the squamosal of Zuniceratops turned out to be the ischium of Nothronychus. Science works by reciprocal illumination: we correct our misjudgements and build on that new information. As you can see in the new PeerJ paper, those turtle parts DO look fairly furcula-like at first glance.”

Mistakes of omission and commission DO happen to all paleontologists.
whether prior to or during publication. Many of those are reviewed and repaired here. On the flip side, I’m still finding mistakes and creating updates in my own work. It’s all part of the process… and we should all keep that in mind.

What should NOT be part of the process
is the practice of holding up past mistakes as a reason to reject a new manuscript. Try to start every day fresh. Try to sprinkle in a little praise before and after every criticism. And, kids, always beware of black-washers and data deniers. They don’t practice what Dr. Holtz preaches.

Li et al. 2015. A new species of Xinpusaurus (Reptilia: Thalattosauria) from the Middle Triassic of Southwestern China. Journal of Vertebrate Paletontology Abstracts


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