Alligator snapping turtle

Abstract: Few descriptions of the development and sequence of chondrification and ossification of the entire skeleton of turtles exist, particularly compared to other groups of reptiles. In this study, the embryonic skeleton and its ontogenesis are described for the Alligator Snapping Turtle, Macrochelys temminckii (Chelydridae). Morphological descriptions utilize cleared and double-stained embryonic specimens and form the basis of comparison of the ontogenesis of the skeleton between this species and its extant sister taxon, Chelydra serpentina. The embryonic chondrocranium, as well as the sequences of formation and ossification of the entire skeleton, are compared between these closely related species, and afford a unique opportunity to examine differences in their patterns of skeletal formation. In M. temminckii, the first elements to ossify (Stage 17) are associated with the dermatocranium and upper jaw, followed by elements of the palate, lower jaw, and long bones of the limbs. In both species the majority of endochondral braincase elements (prootic, opisthotic, supraoccipital, and exoccipital) ossify after the majority of dermal elements of the skull. The sequences of formation of the chondral primordia of the limb elements, as well as ossification of autopodial elements, are generally congruent between these species. J. Morphol. 263:71–106, 2005. © 2004 Wiley-Liss, Inc.

Abstract: The alligator snapping turtle ( Macroclemys temminckii ) is a long-lived, slow-growing chelydrid tur- tle found in Gulf of Mexico drainages from Florida to Texas (U.S.A.). Populations are thought to be depleted throughout the range due in part to an increased harvest in the 1960s through 1980s. To identify population and evolutionary units, 420 base pairs were sequenced within the mitochondrial DNA control region of 158 specimens from 12 drainages. Results indicate substantial phylogeographic structuring and strong popula- tion-level separations among river drainages. Eight of 11 haplotypes were observed to be river-specific, provid- ing diagnostic markers for most drainages. Three partitions are resolved in the mtDNA genealogy, corre- sponding to the eastern, central, and western portion of the species' range. These separations coincide with recognized biogeographic provinces. The population structure by river system indicates that many drainages are distinct management units, with the Suwannee River lineage possibly deserving special attention, based on the criterion of genetic distinctiveness. The partitioning of M. temminckii into river-specific populations il- lustrates the management framework and conservation challenges that apply to a broad array of riverine species. Drainage-specific molecular markers may be used to identify the geographic origin of turtle products in the marketplace.

Abstract: Much of the demand for turtle meat in North America and Europe during the past four centuries has been met using green turtle (Chelonia mydas) and other marine turtles. As stocks of marine turtles dwindled, harvest of the alligator snapping turtle (Macroclemys temminckii), the largest freshwater turtle in North America, increased in the south-eastern USA. As a result, this species has declined and is now protected in every state of the USA except Louisiana. There is concern that the remaining legal trade in turtle products may serve as a cover for illegally harvested species. To assess the composition of species in commerce, we purchased 36 putative turtle meat products in Louisiana and Florida. Using cytochrome b and control region sequences of the mitochondrial genome, we identified 19 samples as common snapping turtle (Chelydra serpentina), three as Florida softshell (Apalone ferox), one provisionally as softshell turtle (Apalone sp.), one as alligator snapping turtle, and eight as American alligator (Alligator mississippiensis). It appears that M. temminckii is no longer the predominant species in markets of Louisiana. The presence of alligator meat in a quarter of the samples indicates that the trade in turtle products is not entirely legitimate. As is often the case for unsustainable wildlife harvests, large, esteemed species, such as green turtle and alligator snapper, have been replaced by smaller, more-abundant or mislabelled species, a phenomenon we refer to as the mock turtle syndrome.

Abstract: -We conducted a telemetry study of subadult alligator snapping turtles (Macroclemys temminckiz) to investigate movement and habitat use. Available habitat consisted of baldcypress forest (Taxodium distichum) (69.1%) and open channel (30.9%). Twelve (three male, nine female) turtles from Bayou Desiard in northeast Louisiana were each equipped with an ATS external radio transmitter and returned to the capture location within 2 h. A total of 1327 location fixes were recorded from March 1992 toJune 1993. At each fix location the date, time, water temperature and depth, direction from last fix and capture site, and nearest shoreline, and habitat were recorded. Significant differences were noted between male and female mean fix distance (males = 352.2 m, females = 160.3 m), mean percentage of movement fixes (males = 62.7%, females = 42.7%) and mean home range length (males = 3495.1 m, females = 1423.2 m). The percentage of movement fixes and fix distance was highly correlated with water temperature but not with the size of the turtle. Turtles preferred the baldcypress forest to open channel. Males and females had significant differences in microhabitat use; 56.1% of male fixes were associated with structures (e.g., logs) compared to 79.7% for females. Turtles returned to specific microsites and there were no overland movements. Subadult and adult alligator snapping turtles in Bayou Desiard have similar movement patterns and habitat use.