Home › Forums › Diamondback Terrapins › identification
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December 4, 2000 at 11:18 am #13864allman_p
Hi, What can you tell me about natural color/pattern variation in the ornate and other terrapins. As a step in our “soon-to-be-happening” surveys in southwest florida I met with someone that has been trapping crabs (mostly terrapins) in this area for many years. He is a research biologist and plans on publishing a paper soon. I saw many of his frozen specimens over the weekend and found much variation. He believes (his theory) the 10,000 islands area holds mangrove and ornate terrapins and there is an area where they are hybridizing. Many of his turtles were very dark with only one or two spots of orange around the carapace. I wish I had photos of all of these, perhaps I will in a few months. How certain can I be identifying turtles based on appearance alone? He had me pretty convinced that these turtles are not true ornates. I know this possible new subspecies in the florida bay may play a factor in this as well. For each of his turtles, he took tissue samples and blood samples and is working with someone in Florida to do some genetic work. Any thoughts?? Phil Allman Environmental Specialist Collier County Natural Resources Naples, Florida 34112
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December 4, 2000 at 6:43 pm #13865Chun-Ming Chew
Phil, Personally, I think ornates are probably one of the easiest subspecies to identify. Their color and pattern is relatively consistent from population to population. For the most part, skin color varies from white to gray; normally peppered with small dark spots although specimens do exist with no visible spotting. One pattern you will not normally find on ornates are bold, dark streaks on their skin – it’s almost always spotted. Most specimens also have a diamond shape on the top of their skulls which is slightly off color from its skin. Although plastron coloring and pattern is very variable (orange to black, patterned or solid), carapace color is always black or gray with orange/yellow scute centers. Sometimes the color of their carapace tends to fade with age and reveals more of the underlying orange/yellow pigment around the scute centers, and sometimes the opposite happens where the scute color is obscured by the encroaching melanin. Vickie’s files are full of examples of ornates. If you need more pictures, you can also go to the Terrapin Keeper section of my website, where other specimens are also pictured (http://www.geocities.com/dterrapin/keeper.html). On the other hand, the few pictures of mangroves that I have seen seem to indicate quite a variation. The Upper Keys mangrove which is alluded to be a new subspecies looks a lot like an ornate and sounds a lot like your description of the frozen specimens. The only difference appears to be that the spotting on the specimen I saw was so acute that most of them were fused together to form a dark background color, unlike ornates, where spotting is sparse and the contrast between spots and skin is very significant. As for true mangroves, a tell-tale trait to me is their smooth carapace and streaked skin pattern. Skin color ranges from khaki to gray and is usually streaked, although spotted specimens also exist. Carapace color also ranges from olive to gray. I’m not sure where the 10000 Islands are, but according to Bartlett, ornates’ range ends at Key Largo. Normally, with a little experience behind you, identifying dbts shouldn’t be too difficult; especially based on geographic locations. However, the possibility of an undescribed subspecies in addition to dbt propensity to integrade really throws a curve into the whole thing. I don’t really see any other possible way to identify them since genetically, they shouldn’t be much different either. I’m not very sure what criteria taxonimists used to differentiate between the subspecies other than geographic location and physical variation. I think the same rules that apply to money apply here. Bank tellers are trained to identify true dollar bills in order to spot a counterfeit. I would probably do the same thing and train myself to accurately identify ornates and mangroves in order to be able to spot integrades, etc.. Otherwise, the only other option might be to cook the frozen specimens and identify differences in meat texture and taste! I’m sure all the research done on terrapin farming would come in handy. Sorry, couldn’t resist that one – naturally, obtaining specimens for preservation and study is a sore point with us captive breeders! Cheers, Chun — In diamondbackterrapins@egroups.com, allman_p
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December 5, 2000 at 8:28 am #13868Scott Howard
Nice touch Chun… Phil, I have observed ornates in the wild from around Tampa to the central panhandle. I have not seen intergrades in the north direction until about the santa rosa beach area west. There are long stretches of open beach unsuitable for the dbts between bays and estuaries. These divide populations to some extent. In the 10000 islands area you will have to find an isolated but common trait across the area to call a possible subspecies. Mitochondreal DNA might be your best bet on characterizing populations. I will back Chun in his descriptive remarks. I would also like to reiterate the skin colors are extremely variable and striping is only more common in mangrove terrapin populations. Carapaces of comparably aged and sexed individuals in different populations may be the best key. I hope this helps. Scott — In diamondbackterrapins@egroups.com, “Chun-Ming Chew”
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