STL Science Center

STL Science Center

24 December 2017

Holidays and the New Year

Good afternoon all. As promised, in the new year we will see a new name and some new branding to this site. We will not forget dinosaurs entirely, but we will widen our scope to more and more fossil animals from many different families. This week, however, there is going to be a short hiatus and next week, rather than a specific animal, we will look at the new images and banners (provided I put something together in time) and during the first week of the new year I will have a bit of a surprise as far as topics, but that can wait. For now, though, here are some old holiday images I have posted in the past. Regardless of what you celebrate, happy holidays and enjoy your week off school or work or whatever!

22 December 2017

Few Images

Han, et al. 2015
There is a lack of images for Hualianceratops for one main reason: there is very little skeletal material known and that material is almost all in the middle portion of the skull. Any ornamentation or odd body shapes are unknown to us with the material we possess at this time. Therefore, instead of showing a really imaginative or well done image that we have not seen this week. Instead, you will find an image from the descriptive paper summarizing the placement of the bones within the living animal's skull. This reconstruction of the skull labels the known material of the skull also; quadrate (q), postorbital (po), jugal (j), maxilla (ma), dentary (d), and predentary (pd). The scale bar of 5 cm shows us how small this animal was as well. The entire head was not much longer than about 15 cm, which is fairly small for what we think of dinosaurs. However, there were many small dinosaurs about this size and, for many lineages, starting off small was quite normal before we see the enormous hulking dinosaurs of later generations, in this case giants like Triceratops.

19 December 2017

Short History Lessons

Many partial remains do not generally introduce a large amount of independent study in the annals of publication. The reason, of course, is that partial remains do not contain a lot of material to be described or to guide inferences into form or function. The material that is known for Hualianceratops, for example, is a minimalistic (not in a derogatory way) collection of cranial elements from a single individual that have not been studied much beyond the scope of the initial description and phylogenetic comparisons (newly published) made in other papers by some of the original authors. The original description, remember, was the work of a collaboration between paleontologists associated with the Institute for Vertebrate Paleontology and Paleoanthropology (IVPP) and George Washington University published through The Public Library of Science as Han, et al. 2015. As stated earlier, there are few studies of this animal outside of these two studies. One study that has specifically mentioned and discussed Hualianceratops in a different context, though, is Maiorino, et al. 2017. This paper discusses biomechanical function of ceratopsian dinosaurs during feeding. What that means, in layman's terms, is that the paper describes how ceratopsian dinosaurs eat their food. The paper also addresses differences in the form of the ceratopsian skull across species.

17 December 2017

Longer Videos Today

Rather than go into all kinds of news sources and random short videos, today I will quickly share a longer video that discusses the (then) newly described dinosaur Hualianceratops. Enjoy the news and facts presented in this short video and share it around.

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:

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.

06 December 2017

Papers and Anatomy

In 2007 Suzhousaurus was officially described and announced to the world as a "Large Therizinosauroid" of Northwestern China. The description available online through Acta Geologica Sinica (the English edition for those that cannot read Chinese characters). The description includes detailed color photographs of the skeletal remains as well as maps of the region from where it had been recovered. Therizinosaur specimens and their stratigraphic ages are also cataloged in the description paper. The phylogeny of the therizinosaurs is discussed briefly, but only enough to describe where the new dinosaur Suzhousaurus fit into the family tree. The description of a newer specimen in 2008 by Li, et al. contains more descriptive information about individual skeletal elements of this new Suzhousaurus megatherioides specimen that was discovered in the same general locality as the type specimen (Gansu Province). The diagnosis of some of the material is revisited and redescribed as well as the new material. However, the heart of this description is in the new material and stretches in great detail for a number of pages. Comparisons to other therizinosaurs round out the discussion, but the overall phylogeny of therizinosaurs is not broached in this paper.

03 December 2017

A Presentation for All

This video has an oddly hushed voice reading the facts and offering interpretation, but the strange huskiness of the presenter is a little odd in spots. Despite that, of course, there are a lot of important facts about the therizinosaur Suzhousaurus that are contained within the video. Clearly it was a wide-cast net for a project, but it is a lot of information that is very important for better understanding of the dinosaur. Fact pages on the internet are found sparingly, but there is a Live Science popular science article from around the initial time of publication that helped to announce and disseminate some of the facts about Suzhousaurus.

02 December 2017

Chinese Therizinosaurs

©Michael B. H. under GNU Free Documentation License
Suzhousaurus megatherioides (Li et al., 2007) is an Early Cretaceous therizinosaur discovered in Gansu, China, a region in the northwestern portion of the country. The name refers to Suzhou, the ancient name for the Jiuquan area of Gansu where the fossil was discovered. Interestingly enough this region is the northwestern region of this northwestern province. The specific epithet references the similarity of the postcranial fossil to Megatherium, the genus of Giant Ground Sloths. A significant portion of the skeleton has been described. There is an interesting phylogenetic confusion about Suzhousaurus and the lost "Nanshiungosaurus" type specimen; a thereizinosaur genus described with two species (N. brevispinus Dong, 1979 (type) and N. bohlini Dong and You, 1997). We will attempt to look more deeply into this later this week. Suzhousaurus currently sits in a basal position within the therizinosauridae and will therefore tell us a lot this week about what defines therizinosaurs in relation to other theropods. We will find, additionally, what makes the diet of both Suzhousaurus and other therizinosaurs different from other theropods.

01 December 2017

Rodents of North America

Reconstruction of the skull of
H. andersontau from Korth 1992
The final animal this week is a small rodent known as Hitonkala contains two species: H. andersontau Macdonald 1963 and H. macdonaldtau Korth 1992. The meaning of the name is very straightforward for this animal. Though some of the other species we saw this week had names that were multi-part translations, Hitonkala simply means "mouse" in Sioux. Hitonkala andersontau is known from isolated teeth and four skulls and H. macdonaldtau, however, is known from a fairly large collection of skulls, teeth, and mandibles. The descriptions of both Macdonald and Kroth detail the teeth in minute detail, but there is not as much description space dedicated to the skulls or any of the postcranial material (I have not found any described at all unfortunately).