Historical Descriptions of Concentric Diamondbacks

Regarding Concentric DBTs, I’m not sure how useful historical descriptions are to present captive breeding efforts; but, being a historian by trade, I tend to start with the oldest scientific descriptions for a place to start. The best I’ve found is the 1904 “Key to the Species and Subspecies of the Genus Malaclemmys,” by William Perry Hay in his “Revision of the Genus Malaclemmys . . .” This was published as a report in the bound annual volume for the US Fisheries Dept. and also as a separate, small soft-bound pamphlet (complete with beautiful color plates). Hay published his report because he was already aware of the unsustainable harvest of dbts for the food market and he intended this study to set a benchmark for future captive propagation efforts. Most of his observations were of the various subspecies of dbts that had been shipped into the impound lots around Crisfield, Maryland. So, the study is incomplete in that it was based on descriptions of subspecies shipped into the pounds rather than on field observations in the various habitats. Because this report is difficult to find today, I re-typed Hay’s 1904 descriptions of the five subspecies then identified and posted them to the list a long time ago. Vickie created a folder and stored them in the group’s Files under the title “Key to Species and Subspecies of the Genus Malaclemmys.” I would encourage anyone interested in the subspecies and color phases to check out this historical information to serve as a starting point. I apologize to those who have already read my posts on this before; but for newcomers, I think it is interesting to note that Hay only defined the following five subspecies in 1904: 1) M. centrata concentrica – The Chesapeake Terrapin 2) M. centrata – The Carolina Terrapin 3) M. littoralis – The Texas Terrapin 4) M. macrospilota – The Florida Terrapin 5) M. pileata – The Louisiana Terrapin Hay did note that dozens of local names were used in the markets to promote sales in the food trade with the “true” Chesapeake considered to be the best and most valuable. Pileatas were the least desirable in the northern food markets, but were prefered in their native New Orleans locale. As we’ve discussed here several times, the northern impound lots serving the food trade that Hay describes did allow for interbreeding of virtually all of the subspecies which was then followed by the massive captive propagation program at the Beufort, NC, Fisheries station (circa 1920 to 1950??) that annually reseeded much of the east coast with yearling dbts from predominantly gray carolina stock. Specifically regarding Concentrics, Hay’s 1904 report, as well as several other later related Fisheries dbt reports, stated that the lightest, most strikingly white-skinned concentrics with the most visible contrasting circles in the shells came from a specific population in Connecticut that was well known in the food trade. Can anyone comment on whether such a population exists there today? Hay also reported in 1904 that the lightest M. centrata concentricas came from the north. The shell and skin tended to darken until it was almost solid black in Virginia where M. centrata concentrica (northerns) intergraded with M. centrata (carolinas). He seemed to suggest that lighter concentric phases found in Virginia and on down into the Carolinas were light phases of M. centrata (carolinas) while dark skinned phases found in that area would be the southernmost and typically dark phase of M. centrata concentrica (Chesapeakes or what we would call northerns today). One seller I have dealt with uses this differentiation to class wcs in the Norfolk, VA, area. Each of the subspecies descriptions did note the tremendous variations in skin color and shell patterns present in each of the subspecies populations shipped into the pounds that Hay was able to observe. He noted that both M. centrata concentica and M. centrata populations could have very white skinned individual specimens with highly contrasting dark brown or black concentrics on light shells amongst the variations. I recognize that there has a been a trend in the present trade towards making the term “Chesapeake” phase much more limiting than what Hay meant by that term in 1904. It will be interesting to see DNA analysis of the various dbt populations to further unravel the mysteries of the subsepecies and the color phases. Todd _Ǖ___Ǖ__Do You Yahoo!? Yahoo! Health – Feel better, live better