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RE: Horner's Pachy Lumpin' - Your Thoughts?

There's also this related ref:
Anat Rec (Hoboken). 2009 Sep;292(9):1370-96.
The facial integument of centrosaurine ceratopsids: morphological and 
histological correlates of novel skin structures.
Hieronymus TL, Witmer LM, Tanke DH, Currie PJ.
Department of Biomedical Sciences, Ohio University College of Osteopathic 
Medicine, Athens, Ohio, USA. h.tobin@gmail.com
The horned dinosaur Pachyhinosaurus possesses rugose bony bosses across the 
skull roof in lieu of the projecting bony horn cores seen in most ceratopsians. 
This elaboration of typical ceratopsian ornaments provides an opportunity to 
test hypotheses of ceratopsian facial skin morphology and function. We analyze 
bone morphology and histology associated with several classes of skin features 
in extant amniotes using a classification tree analysis. We isolate key 
osteological and histological correlates for unpreserved skin structures, 
including both a pattern of pitting and resorption characteristic of muskox 
(Ovibos) frontal horn boss, and a pattern of metaplastic ossification 
characteristic of rhinoceros nasal horn boss. We also describe correlates for 
other skin features, such as epidermal scales and horn sheaths. Dermatocranial 
elements from centrosaurine ceratopsians are then examined for the same 
osteological and histological correlates. From this comparison we propose that 
the rugose bosses that replace horn cores in many centrosaurine dinosaurs, most 
notably Achelousaurus and Pachyrhinosaurus, were covered by a thick pad of 
cornified skin derived from the caudodorsal side of the primitive horn sheath 
comparable to the horny boss of extant muskoxen (Ovibos). We examine extant 
taxa with skin morphologies similar to Pachyrhinosaurus for consistent adaptive 
relationships between structure and behavior. We determine that high-energy 
headbutting is consistently associated with the acquisition of thick cornified 
pads, seen in muskoxen as well as helmeted hornbills [Buceros (=Rhinoplax) 
vigil] and African buffalo (Syncerus). The association of the bony ornaments of 
Pachyrhinosaurus with risky agonistic behaviors casts doubt on the role of 
species recognition as a primary selection pressure driving the diversity of 
all ceratopsian horns. We conclude that social selection (a broad form of 
intraspecific competition) is a more appropriate explanation for the diversity 
of centrosaurine ceratopsian ornaments in th!
e Late Cr

Guy Leahy

> Date: Tue, 12 Jan 2010 09:44:43 -0500
> From: tholtz@umd.edu
> To: afarke@gmail.com; ddkrentz@charter.net
> CC: john.bass@ntlworld.com; dinosaur@usc.edu
> Subject: RE: Horner's Pachy Lumpin' - Your Thoughts?
>> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
>> On Behalf Of Andrew A. Farke
>> David Krentz wrote:
>>> I seem to recall pitting to occur in adult Einiosaurus' 
>> orbital horns. I think the reference was Sampson?
>> Yes, the Sampson et al. reference that Tom mentioned. I would 
>> also point interested readers towards this one, which 
>> provided further detail:
>> Tanke, D.H. and Farke, A.A. 2007. Bone Resorption, Bone 
>> Lesions and Extra Cranial Fenestrae in Ceratopsid Dinosaurs: 
>> A Preliminary Assessment. pp. 319-347. In: Horns and Beaks: 
>> Ceratopsian and Ornithopod Dinosaurs. Edited by K. Carpenter. 
>> Indiana University Press, Bloomington.
> D'oh! Apologies for leaving that one off, too: highly important paper in
> this context.
> Thomas R. Holtz, Jr.
> Email: tholtz@umd.edu Phone: 301-405-4084
> Office: Centreville 1216 
> Senior Lecturer, Vertebrate Paleontology
> Dept. of Geology, University of Maryland
> http://www.geol.umd.edu/~tholtz/
> Fax: 301-314-9661 
> Faculty Director, Earth, Life & Time Program, College Park Scholars
> http://www.geol.umd.edu/~jmerck/eltsite/
> Faculty Director, Science & Global Change Program, College Park Scholars
> http://www.geol.umd.edu/sgc
> Fax: 301-314-9843
> Mailing Address: Thomas R. Holtz, Jr.
> Department of Geology
> Building 237, Room 1117
> University of Maryland
> College Park, MD 20742 USA