ARITCLE REVIEW: Crocodilian Behavior: a window to dinasour behavior?

Parental Care

http://ejournals.ebsco.com.nuncio.cofc.edu/Article.asp?ContributionID=23407184

http://www.tandfonline.com.nuncio.cofc.edu/doi/pdf/10.1080/08912963.2011.560723?&userIP=153.9.241.102

An International Journal of Paleobiology

Crocodilian Behavior: a window to dinasour behavior

Authors

Peter Brazaitis and Myma E. Watanabe

A phylogenetic tree is ordered traits that are considered to be ancestrial and traits that are considered to be derived. Understanding what traits are derived and what traits are considered to be ancestrial is valuable when infering relationships among organisms past and present. Dinasours as we all know are extinct because of this behavioral and structural traits can not be directly or physically observed. One has to look at phylogenetic relationships in order to understand some of these behavior and structural traits. This article compares similarities between Aves and Crocodylia along with phylogenetic relationships between Aves Crocodylia and Dinasours. the comparison the article infers behavioral and structural similarites found in dinsaours  Crocodylia origins can be traced back to the early Triasic period.

Crocodylia and Aves are the only current living representatives of the Archosauria. Understanding similarities in structures and behavior among these two groups can give more in depth information on what traits are considered to be ancestral traits and what traits are considered to be derived.

Crocodylia and Dinosaurs common ancestor is closely related to Euparkeria. The common ancestor split into two different lineages one being Crurotarsi which lead to Crocodylia and Ornithodira which lead to Aves and Dinosaurs. This phylogenetic relationship among Aves, Crocodylia and Dinosaurs allows the article to argue that the behavioral similarities between Aves and Crocodylia would be an ancestral trait that would be present in Dinasours as well.

The Biogeography of Crocodylia also supports the age of crocodylia's phylogeny. Crocodilya have a wide distribution across the globe. Crocodylia do not do well in salt water and would be unable to cross the vast oceans of current continental positions. The origin of the distributions can be traced back to Pangaea and Gondwanan. The source of origin of the species would be very hard to trace back past Pangaea considering the different Continental structures over history. One can conclude that the physical structure of Crocodylia would be a restraint when dealing with Quantum Dispersal. Because of this Diffusion as a dispersal method would be more appropriate in understanding Crocodylia's distribution.

Similarities between Aves and Crocodylia would be Amino acid Structures in B- Keratin. Crocodylia and  most Aves make vocal communications. Seasonal change in oviducts of the American Alligator coincides with similar homologous structures found in birds.

Alligator communication can be shown through the variation in types of calls

 

The similarities between Aves and Crocodylia vocalization gives evidence in support for Dinosaur vocalization. Similarities in female size and egg size of birds and crocodylia gives evidence for the article to hypothisize that some Dinosaurs like Oviraptor, Citipati, Troodontid, Oviraptor, and Troodon had male parental care. Calcium deposite found in fossil bones near or on nesting sites showed no reapsoption. Females would have reapsorption of calcium in the bone from laying eggs.

The article gives great evidence for relationships between Crocodilian behaviors and Dinosaur behaviors. The article also supports parental care in Dinosaurs. The one issue I found in the article is the ability to characterize whether or not male or female parental care. The fossils calcium level could be affected in the fossilization process or the years of weathering since then. Also what if male and female Dinosaurs shared nest attendance responsibilities. Showing the presences of male nest attendances does not rule out female parental care. The article is a great example on how phylogenetic trees can take a look into the past, and gives reasoning for conservation of all species not only the ones subjected in the comparisons. Behavioral studies cannot be present in an organism that is extinct. Understanding current living behavior characteristics could give look into the past, so conservation of all species is imperative for future advances in science.


By

Philip Melton