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Functional aspects of titanosaur osteoderms
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- Universidade Federal do Rio de Janeiro
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- Document Type:
- Poster
- Date:
- Received 21 July 2007 03:05 UTC; Posted 26 July 2007
- Subjects:
- Evolution and Ecology
- Abstract:
Though titanosaur osteoderms are not common findings, these elements are recorded widely in Gondwana and part of Laurasia. This assembly known by the date offers few resources for studies on the ecology of this group of dinosaurs. Recently, some eggs bearing titanosaur embryos with preserved skin, from Patagonia, Argentina, may shed some light on the function and disposition pattern of these dermic bones. Some of the skin patches associated with the titanosaur embryos show two distinct patterns of tuberosities: a longitudinal row and rosettes, both composed of closely attached tuberosities. These tuberosities do not seem to be ossified, but this might be due to the ontogenetic stage of the titanosaurs. Here we propose that these tuberosities might have been ossified in later ontogenetic stages, and then turning into real osteoderms providing physical defence for the juvenile titanosaurs. Amongst the remains of large titanosaurs like Mendozasaurus neguyelap some osteoderms were recovered, but it is contrasting small to the animal when compared to other dinosaurs. These bones would not provide real defensive advantage to an adult titanosaur as they are small and also have a very spongy internal structure. This apparent fragility also may be the reason that few titanosaur osteoderms have been preserved. In comparison, the tuberosity of a young titanosaur is much larger than an adult osteoderm and its body armor would be much more effective against small predators like notosuchian crocodyliforms and small theropods. And if the titanosaur osteoderms are originated from the embryo’s tuberosities, the disposition of these elements in an adult animal would be very distant to each other. The calcium reserve may be considered as functional for an adult titanosaur though.
- Presented at:
- III Jornada Fluminense de Paleontologia, 10 December 2006
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- This document is licensed to the public under the Creative Commons Attribution 2.5 License
- How to cite this document:
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Marinho, Thiago. Functional aspects of titanosaur osteoderms. Available from Nature Precedings <http://dx.doi.org/10.1038/npre.2007.508.1> (2007)
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Julia Heathcote on 08 August 2007 22:00 UTC
I have commented more fully on my own blog (http://www.juliaheathcote.com/2007_08_01_archive.htm#2256710484561536251), but will summarise my thoughts here.
My only real complaint is that, through the nature of the publication format, there are no references. Mr Marinho has been in contact with me since I raised this issue, and has offered me some pointers, but it is a general point that would be useful in future posts for all authors.
A fellow blogger, Laelaps, pointed out that, effective though osteoderms would have been in protecting the juveniles’ backs, the belly and neck would still be exposed. But it appears that sauropod “broods” are about the same size as theropod “broods”, and there is evidence for theropods caring for their young. If sauropods were indeed too large to look after their nurseries, then some form of protection must have existed for juvenile sauropods, whether that protection is in the form of osteoderms, rapid growth or just safety in numbers.
I found the abstract very interesting, and I am looking forward to further discussion with Mr Marinho on the subject at a later date.