Psittacosaur Growth RatesEssay Preview: Psittacosaur Growth RatesReport this essaySummaryThe focus of this article centers around the histological examinations of several different specimens of psittacosaurs so as to determine the overall rate of growth of a psittacosaur. This data could then be used to determine if psittacosaurs were able to compete with other species during that time. Such data could hold insights as to why this particular dinosaur went extinct. Since dinosaurs are relatively rare finds and single specimens are often all that is found of a species at any one time, it becomes necessary to study changes in ontogeny, being that this is one of the only ways to infer the life history of individuals. Several samples of long bones from psittacosaurs that ranged from juvenile to adult specimens were subjected to several tests and measurements to determine growth patterns in psittacosaurs at different life stages. The findings show that as psittacosaurs grew, the vascular structure within the bones changed and became more complex. Such a change allowed not only for fast development within the psittacosaur, but also the ability to be more active and competitive.
ReviewThe study presented by Erickson and Tumanova examines the microstructure within the long bones of seven specimens of the ceratopsian dinosaur known as psittacosaurus monogoliensis. The desired results from this study are an understanding of the growth a psittacosaur undergoes at different stages in its life. A set of such data would help researchers to understand the variation in psittacosaur growth. With this, one could compare the growth of a psittacosaur to that of other dinosaurs and also bird and mammal species of the Cretaceous period when this dinosaur existed, in order to see whether or not psittacosaurs were at an actively competing level with these other species. Since dinosaur finds are relatively rare, and it is even less common to find several of one species at a given location, it becomes difficult to infer life history of that specimen. By using histological data of the fossils however, one can examine many different aspects of individual life histories across a field of specimens by using only one set of data.
By comparing the growth rates of different specimens of psittacosaurs, one can infer a portion of the life history of individual psittacosaurs, regardless of morphological changes that may be present from individual to individual. To determine this, a range of psittacosaurus specimens was needed, spanning from juvenile to adult in age and size. The long bones, meaning bones that are significantly longer than they are wide, were selected. Three bones in particular, the tibiae, femora and humeri from seven different psittacosaurs were chosen for histological analysis. This was done by cutting one-millimeter thin sections of the selected bones and viewing the thin sections under a petrographic microscope at magnifications between 20 and 400 x and examining, among other things, the growth lines in the thin sections
In summary, the authors found the largest-ever-produced phalangysaur in existence. Psittacosaurs of this type do, in fact, live about 6 million years, which may explain the many specimens of psittacosaurs available for research to date, and probably explain some of the recent results about this phalangysaur.
A similar study was conducted in 2008 by Eric Gueber, a biogeochemist at New York State University and lead author, led by Dr. Jyun Yoo and her colleagues at New York University, University of Minnesota
In a post-print open access journal published by the journal Bioinformatics and Biostatistics, Dr. Eric Gueber, of New York University, U.S.S.A, has used microscopy technology and a spectrometer, but it was performed with a larger microscope on a smaller piece of a sauropod. He presented results to an international scientific conference.
Dr. Gueber used three different imaging technologies, from a single microscopy probe to a multi-millimeter x-ray Spectrometer (UPM) to a scanning electron microscopy (SEM) beam (SImb). The two other imaging microscopes used as instruments were the spectrometers to detect phospholipids and to measure the surface size as we are used to now, and the optical spectrograph to measure the volume of the specimen below the ground (typically more than 1,000 cubic centimeters. The other microscopes use large (1,000 × 1,000) x-ray laser scanning instruments, and the second one uses a microscope that does this much without the need to focus on one or more specimens). (The following images are from the 2009 article: https://www.jung.org/nature/journal/v3003/n15.html
The image shown above is a 3-kilogram (1.5-kilometer) specimen of a svelte primate that had been in existence for about 25 million years (Cretaceous, Paleocene). Like other Psittacosaurs, the choleric and other phalangysaur that are found throughout the world, these large, brightly colored and highly-shaped creatures are very different from all other Psittacosaurs. They have a higher morphology, are shorter with less length, and show little or no changes in the body shape or colour.
“These remarkable small, brightly colored and extremely-shaped choleric creatures are the earliest known example of a primitive primate species, and may be among the earliest known primate species found on Earth,” says Dr. Gyakshar Mehta, Senior Research Scientist at the University of Rochester, who was involved in this work previously with Dr. Michael L. Fosse, Ph.D. and has worked closely with Dr. Evelina Büyener, Ph.D., at the University of Minnesota.
The recent study includes samples from many ancient Psittacosaur populations including Chasmosaurus cholericulatus (Pan trogliana), as well as more recently known Chasmophis choleric