1904 ID M. littoralis

The last ID from the 1904 Hay publication: Malaclemmys littoralis. Distribution. Salt marshes and channels along the coast of Texas and outlying islands. Characters. Carapace oval in outline, but of nearly equal width at shoulders and hips, the sides convex, straight, or even slightly concave; notch above the neck usually deeper than in the species previously described; carapace much more vaulted, greatest height usually farther back than in the other species, being at top of third vertebral plate; marginal plates in front of the bridge blunt at the edges, behind the bridge sharper and rather strongly revolute; margin of carapace rounded just above the bridge, so that the sharp longitudinal ridge, so prominent in all the other species, is almost wanting; bridge high; plastron narrower proportionally than in the other species; posterior lobe with more convergent sides. Plates covering the shell thin with old age, often becoming so worn away as to expose the bone beneath them; plates on the plastron usually quite smooth, on the carapace sometimes smooth, but usually concentrically ridged or roughly pitted. Head large, the nose blunt. In the male the carapace is flatter than in the female marginal plates from near front of the shell backwards strongly revolute; plates of the carapace much pitted. The color is variable. Of the 250 specimens examined the few males were all dark brown; there were a few females which were almost black, with dark heads, necks, and legs; others were so light a greenish gray as to appear almost white; the majority, however, were brown, varying from rather light yellowish brown to dusky. The upturned marginal plates in the darker colored individuals were orange, but in light-colored specimens were light greenish gray or nearly white; the plastron was usually yellowish, but if the carapace was very light colored, the plastron was nearly white with a faint greenish tint; the markings on the plates of the carapace were always indistinct, but occasionally there was a faint indication of one or two concentric bands near the centre; usually, however, the plates were only slightly and irregularly clouded, or unmarked. The top of the head was usually dusky, but sometimes white, and the upper lip was white in every individual. Then soft skin was everywhere a pronounced green-gray, but thickly marked and more or less obscured by small, nearly circular, black or brown spots. All of the terrapin of this species that I have seen alive came from Rockport, Texas, but they are said to occur as far as Brownsville, at least, and northward as far as Galveston…..It is quite possible that the range of this species and that of M. pileata merge somewhere between Galveston and New Orleans, and it may be that the two will be shown to be more closely akin than is indicated by the classification adopted here. The very dark brown individuals of M. littoralis are very similar in appearance to the Mobile Bay specimens of M. pileata, but may be distinquished by the higher and heavier body and the white upper lip. A very interesting malformation, consisting in the longitudinal division of one or more of the vertebral plates, was observed in many individuals of this species, a condition so common that it was really difficult to pick out a full-grown specimen which did not show it in some degree. As to the possession of the inguinal plate, these terrapin were variable; of 50 specimens examined for this character, 26 had it and in 24 it was wanting. The young of M. littoralis are very remarkable, and in the absence of any other distinctive characters would serve to separate the species from M. centrata. I have secured a good series of the young from eggs laid in one of the terrapin pounds near Crisfield, Maryland. They are much larger than the young of M. centrata, having probably twice the bulk, and seem much more vigorous and lively. The first vertebral plate is raised on the middle line to form a broad, low carina; on the second plate the elevation is greater, and stands out as a smooth boss on the otherwise finely wrinkled plate; the elevation on the third plate has the form of a hemispherical button with a well-marked constriction around the posterior half of the base, so that it stands up prominently above the plate posteriorly but anteriorly slopes into it; on the fourth plate the elevation rises into a knob-like protuberance from a base which is constricted all around; the tubercle of the thired plate is usually the broadest, but the one on the fourth plate is the highest and most conspicuous of the three; all are smooth and polished, while the plate upon which they rest is finely wrinkled. The fifth vertebral plate is flat or with only a trace of an elevation. The color of these young specimens is brownish yellow or horn color, and the margins of all the plates of the carapace are thickened and darker than the remainder of the plate. The centres of the costal plates usually bear a small dark dot, around which there is sometimes a narrow dark ring. Attention has already been called to the knob-like tubercles observable on many specimens of M. macrospilota and M. pileata, and these unquestionably have their origin in structures such as those just described in M. littoralis. In the latter species they seem to disappear with age, but in macrospilota and pileata they persist, in the males at least, for many years, increasing in size very little, if at all, but very conspicuous when present. In the hundreds of adult and young terrapin from the Atlantic coast which have come under my observation, nothing approaching this character has been found, and it will therefore serve to divide the genus into two distinct groups.