STL Science Center

STL Science Center

16 December 2017

The Oldest Ceratopsian

In the Late Jurassic the foundations of the anatomy of a group known as the Marginocephalians was being laid in the ancestors of these animals. One of the oldest recognized ceratopsians, one of two prominent groups that emerged in the Marginocephalia, was recently (2015) described from remains discovered in China. Institute of Vertebrate Paleontology and Paleonathropology (IVPP) V18641, better known as Hualianceratops wucaiwanensis, was recovered in Western China, specifically in the Xinjiang Province in 2002. The expedition that uncovered the remains was led by the IVPP in conjunction with George Washington University of Washington D. C. The description was penned by Han Fenglu and Xu Xing associated with IVPP and Catherine A. Forster and James M. Clark of George Washington. They described a ceratopsian dinosaur the size of a medium sized dog with a name meaning "Ornamental face" (Hua and lian) with ceratops still meaning "Horned Face". As we will see this week, the remains are heavily based on cranial material, so a name that describes the face twice is actually extremely appropriate.

15 December 2017

Before and After Images

Hesperonychus, as we mentioned, appeared in a single movie and has not appeared in many other venues at all. There are some illustrations online and in dinosaur encyclopedias and other books. Many of the artistic impressions that exist of Hesperonychus are very similar in many ways. One of those interpretations was used to create the models for the movie screen Hesperonychus and the before and after images of this concept are similar, yet strikingly different from one another. The initial illustrations for the movie were a collaborative effort, as were the 3D final models, between artists. One of them, Philip Whiteley, has hosted the image seen here on his website showing the concept work and the final product. Notice the dimensional differences and the fluffiness that was enhanced in the final model. The feathers were apparent in the concept as well, and appeared fluffy, but seeing them retained and look alive in the movie was fairly fantastic.
©20th Century Fox and Animal Logic

13 December 2017

Descriptions of Small Dinosaurs

Hesperonychus has not made much of a buzz since it was initially described. That paper, shared on Saturday initially but here again today (Longrich and Currie, 2009), includes the expected high detail photographs of the type material, but it also includes museum material hypothesized, but not necessarily known, to belong to Hesperonychus. The conclusions that caused this material, isolated pedal phalanges, to be referred to this species, was tentative at the time and has been based on characteristics of size and shape that place the toes in the same family and, because of the size, attribute them to an adult animal approximately the size of the estimated adult size of Hesperonychus. These phalanges are described and compared to the phalanges of other taxa in order to justify their reference to this species of dromaeosaur. Key elements of the pelvic girdle that mark the animal as an adult stand as diagnostic characters that separate Hesperonychus from other genera and the possibility of the small dromaeosaur belonging to another genera as a subadult or even as a juvenile. The characteristic growth described here is fusion of the pubes and ilia, a morphology seen in "somatically mature" animals, as Longrich and Currie state. A phylogenetic discussion is presented as well in an attempt to ascertain the precise clade to which Hesperonychus belongs and its position in both this specific and the larger dromaesaurine clade as well.

11 December 2017

Hesperonychus On-Screen

Hesperonychus has made one appearance on a main screen since its description. A clip of the Walking with Dinosaurs movie, shown here, displays their introduction early in the film. If you want to see more of this small carnivore in the movie, I would recommend watching it. The film was produced by the BBC, in part, and some of the same people behind the BBC's television program of the same name. Additionally, this movie is one of the very few dinosaur movies that aims at more realistic animals, including feathering on their animals, among other things.

10 December 2017

Facts About the Western Claw

Hesperonychus facts pages are somewhat rare on the internet. Rather than going through the few that show up individually, here are a couple that are worth reading today:
DinosaurFacts
BBC

There are no fact videos hosted anywhere online. There is a tribute video on YouTube that can be viewed. A lot of the images used in this video, though, are either generic or are not the dinosaur Hesperonychus; the latter are not identifiable enough to recognize at least. The images loop throughout the video. Enjoy!

09 December 2017

The Western Claw

Discovered in Alberta's Dinosaur Park Formation's Cretaceous strata representing the Campanian stage of 76.5 MYA, Hesperonychus elizabethae is a small dromaeosaur known from a pelvic girdle discovered by Dr. Elizabeth Nicholls of the Royal Tyrrell Museum in 1982. The skeletal element remained in storage until 2009 when it was described by Longrich and Currie (A microraptorine (Dinosauria–Dromaeosauridae) from the Late Cretaceous of North America). A number of claws that appear to be allometrically and anatomically related to Hesperonychus, but these have not been described or officially attributed to the small dinosaur. Measuring in at an estimated length of 1 m (3.3 ft) and weight of 1.9 kg (2.2 lbs), Hesperonychus appears to have been a fully adult but one of the smallest carnivores of North America. Despite the small amount of material, the description relied on comparison between this pelvis and the pelves of other dromaeosaurs.
©Nobu Tamura CC BY 3.0

08 December 2017

Drawings of Suzhousaurus

©Masato Hattori
Suzhousaurus is a fairly typical looking therizinosaurid theropod dinosaur. Because Suzhousaurus looks like any other therizinosaur in almost every interpretation that exists, this rather large theropod, estimated to measure approximately 6 m (19.6 ft) and weigh up to 1.3 tonnes, is not the most exciting dinosaur illustration subject. However, the least static of these paleoillustrations is Masato Hattori's low placed, high angled interpretation of Suzhousaurus standing behind short grassy vegetation. This interpretation has a shorter coating of feathers than what is generally depicted on therizinosaurs, but the feathering appears soft and downy; Suzhousaurus may not have been as fuzzy and warm as it appears here, but I do not think that should bother us. It is feasible that Suzhousaurus was more likely to be found in woodlands or at the edges of forests than in a plainscape, as this appears to be, but this view may not mean anything in terms of where the Suzhousaurus is supposed to have been living at the point in time that this illustration may be depicting.