It could be that toroceratops is simply the male version of triceratops… wonder if this has considered?

Good day, Drs. Fowler and Farke. I just want to know if scientists like you could someday reconstruct the biomolecular profiles of ceratopids from preserved viable soft tissues(even if only one step at a time), would stratigraphy also apply to specimens that will be subjected to those kinds of examinations?

Also, Andy Farke (who is much too modest for such self-promotion) just wrote a short note on the Longrich & Field paper stating that the cluster analysis does not provide adequate support for any particular interpretation (Note, Andy still considers Trike-Toro as separate taxa).

http://www.plosone.org/annotation/listThread.action?inReplyTo=info%3Adoi%2F10.1371%2Fannotation%2F4be4a8ad-f2d2-4978-b283-f0569665ed01&root=info%3Adoi%2F10.1371%2Fannotation%2F4be4a8ad-f2d2-4978-b283-f0569665ed01

It is my understanding that other workers also doubt the cluster results based on misapplication of the method. Maybe there will be more on this subject in the near future.

Do we have enough juvenile (nestlings, puppies, and late juveniles) and adolescent (early and late subadults) remains for the other chasmosaurine taxa aside from Triceratops, Pentaceratops, and Chasmosaurus mariscalensis? Because if there is a dearth of material concerning those stages of other chasmosaurine taxa, then we can not say for certain that they generally did not follow the same trend as what had been established in centrosaurines (besides, it has been established long ago that, just like chasmosaurines, centrosaurines also elongate their neck crests as they mature).

However, I give very high praises to your efforts of collecting specimens in order to test them for the presence of those creatures’ original biomolecules. At least I know I’m not the only one who stands up to Dr. Horner’s advocacy of using biomolecular examinations to build a better picture of the species richness of the world before it was hit by that asteroid 65 million BC. Nevertheless, I do lament that only a few teams are willing to do such a daunting task (AFAIK, except for Dr. Scnweitzer’s team, only Dr. Manning’s team and Prof. Lindgren’s team are performing biomolecular examinations of fossil taxa that have the potential to be used for phylogeny). I surely hope that someday, some scientists would discover some workable DNA sequences of those animals’ genes, not just amino acid sequences of some proteins.

>Since it has been established that centrosaurines more or less retained the same numbers and positions throughout ontogeny, if the same pattern also holds true for chasmosaurines…

It doesn’t, and it has been known and published on for over 100 years. Farke (2011) suggested that intraspecific variation in chasmosaurine epiossification number was individual variation; but various other authors (both before and since Farke’s paper) noted an increase from lengthening / expansion of the frill, and suggested increase through ontogeny (See Scannella & Horner 2011). There’s no consensus as to why/how this occurs, but we do see it. We are collecting more specimens with tight stratigraphic data that help figure out what might be going on, but in many ways this is an iterative process; every new specimen we find gives us a little bit more info that helps us (re)interpret previously collected specimens. Some ideas have moved on considerably since the original Triceratops growth paper of Horner and Goodwin, or the synonomy paper of Scannella and Horner.

As far as biomolecules go, their taxonomic potential is probably still very far from being realized in fossils (although the potential is certainly there). We do take samples of Hell Creek bones (of various taxa) for Mary Schweitzer’s research, but I don’t have anything more to do with that process beyond collection so I couldn’t tell you where it is going.

Regarding the number of epoccipitals, I’m wondering if chasmosaurines in general greatly increased their numbers of epoccipitals through ontogeny. Since it has been established that centrosaurines more or less retained the same numbers and positions throughout ontogeny, if the same pattern also holds true for chasmosaurines, it would make the hypothesis that epoccipitals continuously incresed in numbers as the animals age far less likely. Also, I have read your a recent post of yours in the DML. I’m just wondering if someone is also looking for soft tissues preserved inside the limb bones of Triceratops and Torosaurus so that they could be tested for the presence of original biomolecules(obviously I’m more biased towards molecular techniques). Obviously, if the ontogeny is to be well established for the taxa being studied, confirming the differences observed in morphology with the differences and similarities in their biomolecular profiles would be far more effective (Wuster and Broadley, 2007). Because in the case contradictions arise between histological analyses and molecular examinations, the latter type of test is established as giving more reliable results (Eszlinger,N., Krohn,K., Hauptmann,S., Dralle,H., et al., 2008; Itakura, E., Huang, R.R., Wen, D.R., Cochran, A.J., 2011). Hence, before we could establish “who turned into what”, it would be more appropriate to establish first “who is who”. Also, the consensus biomolecular profile of a species doesn’t change with ontogeny (Chapmann, Tobin, and Hood, 1981); only the amounts of the products of the genes switched on and/or off by ontogeny change, but not how the amino acids in those expressed gene products are sequenced.

References:

Chapmann,B.S., Tobin,A.J., and Hood,L.E. (1981). Complete amino acid sequence of the major embryonic β-like globin in chickens. Journal of Biological Chemistry, 256(11), pp. 5524-5531.

Eszlinger,N., Krohn,K., Hauptmann,S., Dralle,H., et al. (2008). Perspectives for improved and more accurate classification of thyroid epithelial tumors. J Clin Endocrinol Metab. September 2008, 93(9):3286–3294.

Itakura, E., Huang, R.R., Wen, D.R., Cochran, A.J. (2011). “Stealth” melanoma cells in histology-negative sentinel lymph nodes. Am J Surg Pathol., 35(11): 1657-65.

Wuster, W. and Broadley, D.G. (2007). Get an eyeful of this: a new species of giant spitting cobra from eastern and north-eastern Africa (Squamata: Serpentes: Elapidae: Naja). Zootaxa 1532, 151-168.

My bad. I said Scannella, but I meant Goodwin. In any case, Horner & Goodwin admitted to using a cast instead of studying the original fossils in their 2009 paper, so my criticism is applicable to them.

Scannella was not an author on the Pachycephalosaurus synonomy paper, so it is inaccurate and unfair to level any criticism (especially incorrect criticism) at him.

@Hikaru

The suggestion that Kosmoceratops MAY be a juvenile Chasmosaurus irvinensis was mine; Scannella and Horner were coauthors on the poster but the hypothesis is something I proposed. I do not believe anyone has suggested that all chasmosaurines increased the number of epiparietals though ontogeny. However, numbers of frill epiossifications vary between Triceratops specimens (sometimes even between left and right sides of the same individual, and are higher in larger specimens), even if you remove Torosaurus specimens from the dataset. Further, ontogenetic increase in epiossifications has been suggested before (on the squamosal) by authors other than Horner/Scannella/Goodwin (see Scannella & Horner papers for refs). The process by which this occurs is currently unknown, but we do need to think up hypotheses that we can test.

But clearly there is some degree of massive morphological change happening in these animals. Check out figure 8 from the paper. These Torosaurus skulls are nearly as different from one another as the bottom one is to Triceratops. It doesn’t take a great leap to imagine the bottom skull’s fill being slightly shorter, slightly more saddle-shaped, and with slightly smaller or with no fenestrae.
http://www.plosone.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0032623.g008&representation=PNG_M

Slot YPM 1831 in between YPM 1831 (the mature Torosaurus) and YPM 1822 (the Triceratops pictured above) and YPM 1831 becomes a pretty convincing transitional form. The only kink here is that YPM 1822 is an old adult based on cranial fusion. But as the paper shows there are other Triceratops skulls of the same morphology that are not as fused. So if toro and trike are distinct, this could be complicated by the fact you’d expect a subadult Toro younger than YPM 1831 to be nearly indistinguishable from a mature Triceratops.

Probably not, given the existence of young Stygimoloch specimens (MPM 7111 & MPM 8111) that are the same size as the near-adult Dracorex, yet obviously recognizable as Stygimoloch ( http://www.childrensmuseum.org/themuseum/dinosphere/draco_rex/dracorex_hogwartsia.pdf ). Besides that, Horner & Scannella didn’t even study the original Dracorex fossils (See the Saulsbury quote).

Quoting Saulsbury ( http://boards.420chan.org/dino/res/16237.php ): “They state that they utilized computed tomography to reveal internal skull development of Dracorex and Stygimoloch in order to reveal ontogenetically (developmentally) derived features. Unfortunately, they did not scan the Dracorex skull or even examine the original fossils. These were donated to a public institution and are available for study. There are, of course, no internal skull features to the resin cast they studied. In fact, the Dracorex skull has been CT scanned twice, both in and out of matrix, revealing fused sutures, an adult feature. Similarly, the jugal and postorbital bones are fused, which is evident upon examining the fossil.”

And where are the southern specimens in all this? According to their online database, the Simthsonian have a couple partial skulls from Utah’s North Horn formation. Where do they fit into all this?