Creature Feature 13

Greetings, fans! I apologize again for not having a Sci-Day last week, but I had preparations to make for my presentation and didn't have enough time. For this week's Creature Feature, we will be looking at the metatherian genus Alphadon!

Model of Alphadon marshi.

Those who may be more well-informed in scientific nomenclature may have noticed that, unlike the previous Sci-Day posts, I did not include a species name. That is because there were actually at least two species from this genus in the Hell Creek formation - A. marshi (the type species), A. wilsoni, two specimens tentatively assigned to those two specimens but may represent distinct forms (poor preservation of the specimens makes identification impossible), and a third, undescribed species. Since it would not be possible to get enough information on the distinct species to justify two separate Creature Features, I will be talking about the genus collectively. As we get into some of the less well-known lineages of creatures from Hell Creek (particularly those with very little information on them), I will be doing similar Creature Features that look at a group of animals rather than just a single species.

Alphadon was a metatherian - the group which contains living marsupials. While remains of this genus from Hell Creek are not very complete, we know that it was a rather small creature (as were most mammals of its time), estimated around 30 centimeters in length. Its dentition suggests an omnivorous diet, which would consist of fruits, insects (and other invertebrates), and possibly small vertebrates. 

 

The main differences between the two species from Hell Creek relates to the morphology of the molars. These differences are mainly based on differences in morphology of the upper molars, as the distinctions between lower molars and premolars are not as distinct (Johanson, 1992). In A. wilsoni, there is a stylar cusp at or slightly anterior to the deepest part of the ectoflexus, and the paracone and metacone are conical on the labial side, whereas in A. marshi they are flattened/concave (Johanson, 1992). Overall, the anatomy of the occlusal surface of the molars is the best way to distinguish between the two species (Johanson, 1992).

Unfortunately, like I said, there is not much information around on Alphadon, probably due to the fragmentary nature of the remains (consisting mostly of isolated teeth and occasional jaw fragments). However, I have done my best given the information available. Also, a sidenote - there was a third species originally referred to the genus Alphadon, but the species has since been reassigned to the genus Nortedelphys (Williamson et al., 2012). Depending on how much I can find about this other species, it may also get its own Creature Feature.

I hope you may have learned a bit more about the small but rather interesting Alphadon!

Acknowledgements:

Johanson, Zerina. 1992. A systematic revision of the North American late Cretaceous marsupial genus Alphadon Simpson, 1927. University of Alberta (Canada), ProQuest Dissertations Publishing. MM73236.

Williamson, T. E.; Brusatte, S. L.; Carr, T. D.; Weil, A.; Standhardt, B. R. 2012. The phylogeny and evolution of Cretaceous–Palaeogene metatherians: cladistic analysis and description of new early Palaeocene specimens from the Nacimiento Formation, New Mexico. Journal Of Systematic Palaeontology, 10(4), 625-651.

Creature Feature 12

Hello, everyone! Sorry about the lack of Sci-Day last week, but as I said on the Facebook page a combination of exhaustion and a cramped schedule made it impossible to get anything ready. Anyways, for today's Creature Feature we'll be looking at the dome-headed ornithischian Pachycephalosaurus wyomingensis!

Pachycephalosaurus wyomingensis model, work in progress.

Pachycephalosaurus was a bipedal ornithiscian dinosaur, though its postcranial anatomy is actually poorly known due to lack of description of such remains (Sullivan, 2006). However, there is a lot known about the very distinctive head - it had a thick dome up to 25 cm thick, with bony knobs protruding from the posterior end and short bony spikes jutting out from the snout. In life, these spikes were likely blunt (Carpenter, 1997).

Pachycephalosaurus had a relatively short skull, with large, rounded eye sockets that faced forward - this suggests that it had well-developed binocular vision. Like many other ornithischians, Pachycephalosaurus had a short snout ending in a pointed beak, with teeth placed in the rear of the jaw. Based on what is known of the postcranial anatomy of other, related pachycephalosaurids, the neck was short and thick, adopting an "S" or possibly "U"-shaped curve in life. It likely had short forelimbs, long hind legs, and a bulky body, counterbalanced by a heavy tail that may have been held rigid by ossified tendons (Organ and Adams, 2005). It was the largest member of the Pachycephalosaur family, at an estimated 4.5 meters in length and weighing in at approximately 450 kilograms (Paul, 2010).

While it was originally thought that Pachycephalosaurs would have used their domes like extant musk oxen or bighorn ship (lining up with their bodies horizonal, and headbutting each other), this is no longer believed to be the case. There are several reasons why this idea is disputed, the foremost of which being that the structure of the skull roof would be unable to sustain the stresses from the impact of such ramming. Additionally, there has not been any evidence of scarring or other damage to the domes of preserved Pachycephalosaurus models; however, recent analyses may provide such evidence (Peterson and Vittore, 2012). Lastly, the articulation of the neck and rounded shape of the skull would be unsuitable for direct head-butting (Carpenter, 1997). However, there is some evidence of adaptations in other species of Pachycephalosaur that would allow for headbutting (Snively and Theodor, 2011). There has been an alternative proposal to the direct headbutting behavior originally proposed for intraspecific combat in Pachycephalosaurs. This alternative is that rather than direct head butting, Pachycephalosaurs would strike rivals on the flank, with the thick body of the animals protecting vital organs from serious injury (Sues, 1978) (Carpenter, 1997).

Perhaps the most interesting thing about Pachycephalosaurus is its hypothesized growth. It has been proposed that the species Dracorex hogwartsia and Stygimoloch spinifer actually represent progressive growth stages of Pachycephalosaurus. The spikes and protrusions from the skull show a great degree of plasticity; additionally, the former two 'species' are only known from juvenile specimens, whereas Pachycephalosaurus is exclusively known from adult specimens. Such evidence, combined with the fact that all three lived in the same place at the same time, has led many to believe that the former two are synonymous with Pachycephalosaurus (Horner and Goodwin, 2009). If this is true, Pachycephalosaurus would have lost the large spikes of Stygimoloch and grown a larger dome with age. Additional research has supported this hypothesis, and has proposed that flat skulled Pachycephalosaurs actually represent juveniles of dome headed adults (Longrich et al., 2010).

"Stygimoloch" spinifer model, work in progress. Compare to Pachycephalosaurus and you will see a great degree of similarity.

This possibility is particularly interesting because such radical changes in anatomy might be widespread in dinosaurs, and there may actually be many species currently described that are actually just growth stages of a single species. However, only further evidence will let us know for sure whether or not this is the case.

I hope this week's Creature Feature has taught you a little more about this fascinating creature!

Acknowledgements:

Sullivan, Robert M. 2006. A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia) (PDF). Late Cretaceous Vertebrates from the Western Interior. New Mexico Museum of Natural History and Science Bulletin 35: 347-366.

Carpenter, Kenneth. 1997. Agonistic behavior in pachycephalosaurs (Ornithischia: Dinosauria): a new look at head-butting behavior. Contributions to Geology 32 (1): 19-25.

Organ, Christopher O.; Adams, Jason. 2005. The histology of ossified tendon in dinosaurs. Journal of Vertebrate Paleontology 25 (3): 602-613.

Paul, Gregory S. 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press: Princeton, NJ. p. 244.

Peterson, J. E.; Vittore, C. P. 2012. Farke, Andrew A, ed "Cranial Pathologies in a Specimen of Pachycephalosaurus. PLoS ONE 7 (4): e36227.

Snively, E; Theodor, J.M. 2011. Common Functional Correlates of Head-Strike Behavior in the Pachycephalosaur Stegoceras validum (Ornithischia, Dinosauria) and Combative Artiodactyls. PLoS ONE 6 (6): e21422.

Sues, H. D. 1978. Functional Morphology of the dome in pachycephalosaurid dinosaurs. Neues Jahrbuch für Geologie und Paläontologie. Monatshefte 1978, 459-472.

Horner J .R.; Goodwin, M. B. 2009. Extreme cranial ontogeny in the Upper Cretaceous Dinosaur Pachycephalosaurus. PLoS ONE 4(10): e7626.

Longrich, N. R.; Sankey, J; Tanke, D. 2010. Texacephale langstoni, a new genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper Campanian Aguja Formation, southern Texas, USA. Cretaceous Research 31 (2): 274-284.

Creature Feature 11

Hello, fans! Today, I'd like to talk a bit about the Nodosaur from Hell Creek - Denversaurus (or Edmontonia ?) schlessmani.

Denversaurus (=Edmontonia?) schlessmani model, work in progress.

Denversaurus schlessmani was a stocky, quadrupedal ornithischian dinosaur, somewhat similar in build to Ankylosaurus. While the two share some overall similarities, they belong to different clades within Ankylosauria. Where Ankylosaurus is in the family Ankylosauridae, Denversaurus is placed in Nodosauridae. Nodosaurs are distinct from Ankylosaurs in several ways. Nodosaurs had proportionally longer snouts, shorter, narrower beaks, and lacked the notorious 'clubs' of Ankylosaurs. Instead, the most distinctive feature of their armor was the large spikes, particularly those protruding from the shoulder region. Additionally, Nodosaurs did not possess the large squamosal plates found in Ankylosaurs.

Currently, it is not completely certain whether or not Denversaurus schlessmani represents a distinct genus, as some sources believe it to be synonymous with Edmontonia (Hunt and Lucas, 1992). The original description based the distinct status of the taxon on the fact that the back of the skull was much wider than in Edmontonia specimens (Bakker, 1988), but later analysis showed that this was actually due to crushing of the remains (Carpenter, 1990), and the species was actually a junior synonym of Edmontonia longiceps (Vickaryous et al., 2004). However, a recent reevaluation of late Cretaceous Nodosaurids supports Denversaurus schlessmani as a distinct taxon based on its phylogenetic position within the group (Burns, 2015).

Current estimates on the size of Denversaurus schlessmani put its length at approximately six meters, and its weight at 3 tonnes (Paul, 2010).

I hope you enjoyed today's Creature Feature! I'm sorry that I didn't have all that much to write, as there is not a ton of information on Denversaurus that I could find. I did what I could, though, and I hope you at least learned something new about this rather interesting creature!

Acknowledgements:

Hunt, A.P. and Lucas, S.G., 1992. Stratigraphy, Paleontology and age of the Fruitland and Kirkland Formations (Upper Cretaceous), San Juan Basin, New Mexico. New Mexico Geological Society Guidebook, 43rd Field Conference, San Juan Basin. Volume 4: 217-240

Bakker, R.T. 1988. Review of the Late Cretaceous nodosauroid Dinosauria: Denversaurus schlessmani, a new armor-plated dinosaur from the Latest Cretaceous of South Dakota, the last survivor of the nodosaurians, with comments on Stegosaur-Nodosaur relationships. Hunteria 1(3):1-23.

Carpenter, K. 1990. Ankylosaur systematics: example using Panoplosaurus and Edmontonia (Ankylosauria: Nodosauridae), In: Carpenter, K. & Currie, P.J. (eds) Dinosaur Systematics: Approaches and Perspectives. Cambridge University Press, Cambridge: 281-298

Vickaryous, M.K.; Maryanska, T.; Weishampel, D.B. 2004. Ankylosauria. In: Weishampel, D. B.; Dodson, P.; Osmólska, H. (eds.). The Dinosauria (Second Edition). University of California Press. 363-392.

Burns, M.E. Intraspecific Variation in Late Cretaceous Nodosaurids (Ankylosauria: Dinosauria). Journal of Vertebrate Paleontology, Program and Abstracts, 2015: 99–100.

Paul, G.S. 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press.

Sci-Day 10: Coevolution

Happy Sci-Day, fans! Today, I want to talk about an interesting phenomenon called 'Coevolution'.

Coevolution is when an evolutionary change in one species causes evolutionary change in another, which itself causes further change in the first species. Essentially, this is a sort of positive feedback - the cycle continues to build on itself until it is interrupted (perhaps by the extinction of one of the two species).

There two main categories of Coevolution: mutualism, and antagonistic coevolution. Mutualism is when two species each use each other as a resource, and evolutionary change that facilitates interaction between them is beneficial to both (benefits outweigh the costs). Antagonistic coevolution is when evolutionary change in one species decreases fitness in another species, inducing a change in that species that then decreases fitness of the first.

Many examples of mutualism exist in nature - one great example is plant-pollinator relationships. One such example is the genus of tropical plants Glochidion and the moth genus Epicephalia. Each species of Glochidion is pollinated exclusively by a single Epicephalia species. Moths actively pollinate flowers and deposit their eggs into approximately 20 flowers. Their larvae then develop in those flowers and consume some fraction of the seeds that result from pollination. Thus, both species rely on each other for reproduction and could not survive without each other (Blumenstiel, 2016).

Antagonistic coevolution has two common types - predator-prey coevolution and parasite-host coevolution. In predator-prey coevolution, the prey species evolve some adaptation to help defend themselves against predators, such as longer legs to run faster, or thick armor to protect from claws and jaws. This reduces the fitness of the predators, and they evolve adaptations to overcome or bypass these defenses. Examples of possible responses to the aforementioned prey examples would include evolving good camouflage so they could catch the prey before it could run, and a stronger set of weapons to punch through the armor. Parasite-host coevolution happens when parasites evolve adaptations to better infect/reproduce inside their hosts, and the hosts evolve adaptations such as changes in the immune system to better resist infection. A commonly used term for antagonistic coevolution is an "evolutionary arms race" - if this is occurring, we should see some association between the level of defense and level of predation of the organisms suspected to have such a history.

Unfortunately, it can be quite difficult to determine whether or not such patterns are occurring in long-extinct species such as those from Hell Creek. This is partially because we cannot observe the animals interacting with each other in life, instead relying on evidence such as tooth marks on fossil bones and overall body proportions.

One example of this uncertainty is the idea that Tyrannosaurids and Ceratopsians were engaged in predator-prey coevolution. For a long time, it was thought that Ceratopsians had evolved frills and horns as greater measures of defense, and the trend towards larger jaws and subsequently more powerful bites was the evolutionary response. However, analyzing phylogenies of these two groups, there does not seem to be a strong overall trend in increased frill and horn size to match increasing bite strength in contemporary Tyrannosaurs. Now, the most widely accepted theory to explain the diversity in structure of Ceratopsian frills and horns is that it was driven by sexual selection and species recognition. In fact, evidence of injuries from Triceratops horns have only been found on the skulls of Triceratops, which is evidence of non-fatal intraspecific combat in this species (Farke et al., 2009).

Coevolution may actually be an idea that Dinosaur Battlegrounds could help paleontologists investigate. As more formations and paleoecosystems are added, it would be possible to look at the functional differences of different lineages through time (and since restorations and variables influencing the simulation are all based on scientific data, their functionality can be safely considered as the most accurate picture of that species at a given time). Then, one could actually alter the variables of an earlier species, such as prey, to more closely resemble those of a derived relative, and look for any changes in the fitness of species that it regularly interacts with. This could provide some level of evidence for a coevolutionary relationship, given enough replication with a large enough phylogenetic sampling.

Well, I hope this has given you a bit more information on coevolution! It's a very interesting topic that truly shows how all organisms are interrelated, and all species have their role to play in the environment!

Acknowledgements:
Blumenstiel, Justin. 2016. Coevolution lecture [Evolutionary Biology class at KU].
Farke, A. A.; Wolff, E. D. S.; Tanke, D. H.; Sereno, Paul. 2009. Sereno, Paul, ed. "Evidence of Combat in Triceratops. PLoS ONE 4 (1): e4252.

Creature Feature 10

Hello, everyone! This week, I've decided to feature a somewhat misunderstood and very amazing squamate. It's time to meet the largest lizard currently known from Hell Creek - Palaeosaniwa canadensis!

Work-in-progress Palaeosaniwa model.

As stated above, Palaeosaniwa canadensis was a very large lizard, reaching an estimated 2 meters in length (Balsai, 2001). Unfortunately, not much is known about this amazing creature, though what is known is very fascinating.

There is one significant misconception about Palaeosaniwa that is relatively widespread - namely, that it was essentially a giant monitor lizard. However, this idea was based on the descriptions of isolated, fragmentary elements, and when more complete remains were found, they revealed that it was more closely related to Helodermatids than it was to Varanus (Balsai, 2001). Still, there are parts of the skull that are missing or poorly preserved, and as such there is still uncertainty as to how closely it resembled modern Heloderma. For example, the anterior end of the snout is missing and as such it is not known whether or not the snout was rounded or pointed (as seen in Heloderma and Varanus, respectively) (Balsai, 2016). One known divergence from Heloderma that is known based on the remains is the proportions of the parietals on Palaeosaniwa were more elongate and less robust, more closely resembling the state seen in Lanthonotus (Balsai, 2016).

Close-up of the head of Palaeosaniwa model. Note the more gradual slope of the snout compared to Heloderma.

Perhaps the most fascinating aspect of Palaeosaniwa is that it may offer insight into the evolution of venom in that group of animals (while originally placed within Monstersauria, that group has been shown in recent analyses (Reeder et al., 2015) to be polyphyletic, and as such I do not know what clade it would belong to). It is likely that Palaeosaniwa was a nest raider, preying on hatchlings and eggs of some of the dinosaurs living in its environment. This is hypothesized due to the similar behavior in its extant relatives, as well as Varanus niloticus, which have even been observed cooperating to raid Crocodylus niloticus nests. Additionally, remains assigned to Palaeosaniwa have been found associated with dinosaur nesting sites, further supporting this hypothesis.

Thus, it is possible that while modern Heloderma primarily use their venom for defensive purposes, it originally evolved as a mechanism for quickly dispatching of the hatchling dinosaurs, as well as offering some protection from their extremely massive and most likely very angry parents (Balsai, 2001). Unfortunately, remains of Palaeosaniwa are not sufficient to determine whether or not it was venomous with any great certainty (Balsai, 2016), and if it were there is no way (as far as I know) to determine the composition of the venom for determining its effects and relative toxicity. Only more detailed remains of the jaw and dentition will give us a better idea as to the validity of this hypothesis.

To sum up, Palaeosaniwa was a very large, possibly venomous lizard that likely preyed on vulnerable hatchlings and eggs of dinosaurs and other nesting animals in Hell Creek. When you play Dinosaur Battlegrounds, keep an eye on your nests in case you find an uninvited guest coming over for dinner!

Well, I hope you enjoyed this week's creature feature! I wanted to go very in-depth with this one, partially because the myth that Palaeosaniwa was a giant monitor lizard has been rather pervasive, and I want to make sure that people have the facts. I also want to give a shoutout to Michael Joseph Balsai, who was extremely helpful with my life-restoration of this species. Thanks to him, I have a better understanding of this amazing creature, and I hope that upon reading this article, you do too!

Acknowledgements:

Balsai, Michael Joseph. 2001. The Phylogenetic Position of Palaeosaniwa and the Early Evolution of the Platynotan (Varanoid) Anguimorphs. Univ. of Pennsylvania - Electronic Dissertations. Paper AAI3031637.

Balsai, Michael Joseph. Personal communication. 2016.
Reeder, Tod W.; Townsend, Ted M.; Mulcahy, Daniel G.; Noonan, Brice P.; Wood Jr., Perry L.; Sites Jr., Jack W.; Wiens, John J. 2015. Integrated Analyses Resolve Conflicts over Squamate Reptile Phylogeny and Reveal Unexpected Placements for Fossil Taxa. PLoS One 10 (3): e0118199.

Sci-Day 9: Dinosaur Metabolism

Happy Sci-Day, fans! Today, I'd like to touch upon a topic that is rather hard to directly investigate... The metabolism of non-avian dinosaurs.

Dinosaur metabolism is very difficult to study or to determine with a great degree of certainty for obvious reasons. Unlike with modern animals, it is impossible to directly measure respiration rates (since doing so requires a live specimen). This means that paleontologists must use other techniques to indirectly determine these aspects of dinosaur biology. Unfortunately, informed inferences are the closest we can get to understanding dinosaur metabolism unless someone manages to create a time machine.

While currently it is agreed that dinosaurs in general had faster metabolic rates than extant reptiles such as lizards and crocodilians, the situation is not black and white. While some of the smaller species may have been truly endothermic, it has been hypothesized that some of the larger species of dinosaur were intertial homeotherms (Paladino et al., 1990), or that many dinosaurs were somewhere in between the metabolic rates of reptiles and birds (Barrick et al., 1996).

One reason it has been considered unlikely for fully endothermic metabolism to be present in all dinosaur species is the fact that the largest dinosaurs grew up to 5 times as massive as the largest endothermic terrestrial animals known. Since maximum size is limited by metabolic rate (due to the fact that the amount of energy required is dependent on both), the significantly larger sizes of dinosaurs when compared to true endotherms is considered evidence of a slower field energy expenditure. In fact, the field energy expenditure curve based on varanid lizards between 2.2 and 45.2kg (FEE = 1.07g^0.735, g = mass of animal in grams) works quite well for dinosaurs, and can be used to explain the larger maximum sizes of the largest species. Using this equation, the field energy expenditure of 59-ton sauropod would be equivalent to that of a 7.5 ton African elephant, and an 83-ton sauropod would have the same energy requirements as an 11 ton Paraceratherium, the largest known terrestrial mammalian herbivore (McNab, 2009). While some might find this surprising given that many people think of lizards as slow, sluggish animals, varanids actually have a metabolic rate that is 3 times higher than that of other lizards, and many live a rather active life, roaming around in their search for food. Additionally, the larger species of varanids can grow VERY quickly (a phenomenon also seen in dinosaurs) given the right conditions (ie allowing for constant optimum body temperature, abundant food - in captivity essentially) - my Nile monitor grew from a 25g hatchling to a 5', 7kg animal in merely 18 months!

Understanding the energetics and energy requirements of dinosaurs is essential for Dinosaur Battlegrounds, as we want to represent the biology of these animals as accurately as possible given current evidence. Using this equation, we can figure out how much energy the creature would need to get from its food in order to survive.

However, there is another piece of the puzzle that needs to be considered - the energy yield per unit mass of the food they consumed (ie units of kJ/kg dry mass). This requires thorough research, as it is critical to creating the mechanic for food. There actually is a paper that gives metabolizable energy amounts for various different plant groups found in the Morrison, most of which were also present in Hell Creek (Hummel et al., 2008). However, there was a massive diversity of angiosperm taxa present in Hell Creek, and as such those were not included in the analysis (Angiosperms were not present in the Morrison) - currently, no data exists for the metabolizable energy/digestibility of the various angiosperm taxa from Hell Creek [at least as far as I'm aware - if I am wrong, please do let me know and give a source, I would greatly appreciate it!], which is a problem, since angiosperms were extremely abundant and likely were a considerable component of herbivorous dinosaurs' diets.

This gap provides the opportunity for a research project - one could replicate the procedure as detailed in the Hummel et al. paper, but using samples of the closest modern relatives of extinct Hell Creek angiosperm taxa. This would need to be done not only with leaves, but also with bark, fruit, and flowers (where applicable). Such a project, while important to Dinosaur Battlegrounds, would also provide very useful data to any scientists working on nutrition/energetics of both modern and extinct taxa, as they could use the published numbers in their analyses. This opportunity for formal scientific research is part of what Dinosaur Battlegrounds is about - we are not just a game, we want to use the game and the process of creating it to further the knowledge of a world long since lost to us by the eroding sands of time.

Well, I hope this has given you a bit of a better idea on dinosaur metabolism, and overall energetics!

Acknowledgements:
Paladino, F. V; O'Connor, M. P.; Spotila, J. R. 1990. Metabolism of leatherback turtles, gigantothermy, and thermoregulation of dinosaurs. Nature 344 (6269): 858-860.
Barrick, R. E.; Showers, W. J.; Fischer, A. G. 1996. Comparison of Thermoregulation of Four Ornithischian Dinosaurs and a Varanid Lizard from the Cretaceous Two Medicine Formation: Evidence from Oxygen Isotopes. PALAIOS 11 (4): 295-305.
McNab, Brian K. 2009. Resources and energetics determined dinosaur maximal size. PNAS 106 (29): 12184-12188.
Hummel, Jürgen; Gee, Carol T.; Südekum, Karl-Heinz; Sander, P. Martin; Nogge, Gunther; Clauss, Marcus. 2008. In vitro digestibility of fern and gymnosperm foliage: implications for sauropod feeding ecology and diet selection. Proceedings of the Royal Society 275: 1015-1021.

Creature Feature 9

Hello, everyone! I hope you're all having a great week so far! This week's Creature Feature covers a rather interestingceratopsian dinosaur, Leptoceratops gracilis.

Unlike its far larger, lumbering cousin Triceratops, Leptoceratops was capable of bipedal locomotion, though forelimb analysis indicates it was capable of walking on all fours despite the fact that it could not pronate its hands (Senter, 2007). Given that some ceratopsian dinosaurs are known to have had quill-like structures on their tail such as Psittacosaurus (Mayr et al., 2002), it is possible that this feature is an ancestral trait in the group, given that Psittacosaurus is basal in comparison to Neoceratopsidae (the lineage that includes Leptoceratops as well as other Ceratopsians such as Triceratops), though there is also the possibility of secondary loss of the character. Until direct evidence of such integument is found in those other species, it is impossible to know for certain.

As with all ceratopsians, Leptoceratops was an herbivore, and evidence based on its cranial anatomy suggests that it had a rather powerful bite (Tanoue et al., 2009). Based on the morphology of the teeth, and wear patterns observed, it is likely that Leptoceratops chewed its food using a mixture of shearing and crushing motions (Lindgren et al., 2007). This would allow it to process extremely tough plant matter.

Given its small size, it was most likely a low feeder. Given that angiosperms were the most diverse plants at the time, it is likely that these formed an important part of its diet. However, despite their relatively low diversity in terms of species, it is also possible that other groups such as ferns and/or gymnosperms were present in larger numbers of individual plants.

Well, I hope this has given you all bit more information about the rather interesting basal Neoceratopsian dinosaur from Hell Creek! Tune in next Tuesday for another Creature Feature!

Acknowledgements:
Senter, P. 2007. Analysis of forelimb function in basal ceratopsians. Journal of Zoology 273 (3): 305-314.
Mayr, G; Peters, S. D.; Plodowski, G; Vogel, O. 2002. Bristle-like integumentary structures at the tail of the horned dinosaur Psittacosaurus. Naturwissenschaften 89 (8): 361-365.
Tanoue, Kyo; Grandstaff, Barbara S.; You, Hai-Lu; Dodson, Peter. 2009. Jaw Mechanics in Basal Ceratopsia (Ornithischia, Dinosauria). The Anatomical Record 292 (9): 1352-1369.
Lindgren, Johan; Currie, Philip J.; Siverson, Mikael; Rees, Jan; Cederström, Peter; Lindgren, Filip. 2007. The First Neoceratopsian Dinosaur Remains from Europe. Palaeontology 50 (4): 929-937.