Evaluating recent taxonomic changes for alligator snapping turtles (Testudines: Chelydridae)

Folt, Brian; Guyer, Craig

doi:10.11646/zootaxa.3947.3.11

Cited by 19 publications

(27 citation statements)

References 9 publications

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“…Parmley (1992) reported fragmentary remains from the Late Miocene of Nebraska but did not provide figures to support this claim. Up to three species of Macrochelys that possibly diverged from one another in the Late Miocene currently inhabit large rivers across the southeastern United States ), but given current debates regarding the validity of all three taxa (e.g., Folt and Guyer 2015), I here recognize a single species, Macrochelys temminckii (Troost in Harlan 1835). The remaining Neogene pan-chelydrid record consists of rarely figured postcranial remains that have been referred to the Chelydra serpentina lineage ( Figure 5).…”

Section: Paleobiogeographymentioning

confidence: 94%

“…Thomas et al (2014) recently highlighted that molecular data allow recognizing three populations of extant Macrochelys, with the population from the Suwannee River of Florida, USA, being sister to the remaining two populations from the Apalachicola and greater Mississippi drainage basins farther to the west. Whether these three populations should be regarded as three , two (Folt and Guyer 2015) or one species (Turtle Taxonomy Working Group 2014) is currently under debate. I am unaware of a molecular study that investigates the three species of Chelydra, but it is reasonable to presume that the two taxa from Central and South America are each other's closest relatives.…”

Section: Craniummentioning

confidence: 99%

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A Review of the Fossil Record of Turtles of the CladePan-Chelydridae

Joyce¹

2016

Bulletin of the Peabody Museum of Natural History

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Turtles of the total clade Pan-Chelydridae have a relatively sparse fossil record that reaches back to the Late Cretaceous (Santonian). The clade was only present in North America during the Cretaceous but spread along unclear routes to Asia and Europe during the Paleocene, only to go extinct on those continents by the end of the Pliocene. Final dispersal to South America took place at some time during the late Neogene. The ecology of stem chelydrids seems to have been similar to that of the extant Chelydra serpentina, although more primitive representatives were more molluscivorous as inferred from their broader triturating surfaces. Current phylogenies only recognize five internested clades: Pan-Chelydridae, Chelydridae, Chelydropsis, Chelydra and Macrochelys. A taxonomic review of the group concludes that of 31 named fossil taxa, 8 are nomina valida, 10 are nomina invalida, 9 are nomina dubia, 1 is a nomen nudum and 1 is a regular, unavailable name.

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Section: Paleobiogeographymentioning

confidence: 94%

Section: Craniummentioning

confidence: 99%

A Review of the Fossil Record of Turtles of the CladePan-Chelydridae

Joyce¹

2016

Bulletin of the Peabody Museum of Natural History

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“…We used range maps of 336 species of non-marine turtles (freshwater turtles and tortoises, excluding only the marine species -hereafter referred to as 'turtles'), which may be viewed in van Dijk et al (2014). We followed the most recent taxonomy proposed by the Turtle Taxonomy Working Group (van Dijk et al 2014) to avoid synonymy, and, we also followed recent re-evaluations of the species Macrochelys temminckii (Folt and Guyer 2015), which was recently divided into two allopatric species. The range maps were rasterized in a grid of 2°  2° degrees including cells with more than 25% of land area to generate a presence-absence matrix of sites (rows)  species (columns).…”

Section: Data Collectionmentioning

confidence: 99%

Time and environment explain the current richness distribution of non‐marine turtles worldwide

et al. 2017

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Ecological, historical, and evolutionary hypotheses are important to explain geographical diversity gradients in many clades, but few studies have combined them into a single analysis allowing a comparison of their relative importance. This study aimed to evaluate the relative importance of ecological, historical, and evolutionary hypotheses in explaining the current global distribution of non-marine turtles, a group whose distribution patterns are still poorly explored. We used data from distribution range maps of 336 species of non-marine turtles, environmental layers, and phylogeny to obtain richness estimates of these animals in 2°  2° cells and predictors related to ecological, evolutionary and historical hypotheses driving richness patterns. Then we used a path analysis to evaluate direct and indirect effects of the predictors on turtle richness. Ancestral area reconstruction was also performed in order to evaluate the influence of time-for-speciation in the current diversity of the group. We found that environmental variables had the highest direct effects on non-marine turtle richness, whereas diversification rates and area available in the last 55 million yr minimally influenced turtle distributions. We found evidence for the time-for-speciation effect, since regions colonized early were generally richer than recently colonized regions. In addition, regions with a high number of colonization events had a higher number of turtle species. Our results suggested that ecological processes may influence non-marine turtle richness independent of diversification rates, but they are probably related to dispersal abilities. However, colonization time was also an important component that must be taken into account. Finally, our study provided additional support for the importance of ecological (climate and productivity) and historical (time-for-speciation and dispersal) processes in shaping current biodiversity patterns.

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“…The study population in Spring Creek occurs within the Apalachicola River drainage and would be assigned as M. apalachicolae by the geographic distribution; however, we follow Folt and Guyer (2015), who retained M. apalachicolae within M. temminckii until a proper morphological or molecular diagnosis documents the two as representing separate individuals. Therefore, we refer to our study population as M. temminckii.…”

Section: Study Speciesmentioning

confidence: 99%

Establishing Reference Demography for Conservation: A Case Study ofMacrochelys temminckiiin Spring Creek, Georgia

Folt

Jensen

Teare

et al. 2016

Herpetological Monographs

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The conservation of large, long-lived turtle species can be a challenging issue because their life-history strategies make populations sensitive to changes in adult survivorship and populations may be difficult to sample. The Alligator Snapping Turtle (Macrochelys temminckii) is a large freshwater turtle species occurring in North America for which commercial harvest has severely reduced populations throughout the species range. Given recent population declines and a general deficit of demographic knowledge for Macrochelys, we conducted a mark-recapture study of M. temminckii from 1997-2013 in Spring Creek, Georgia, USA. We made 166 captures of 75 individuals using baited hoop-net traps and skindiving searches. The observed and estimated population structure described the adult sex ratio as even and adults as more abundant than juveniles. Apparent survival was higher for adult males (0.98) and females (0.95) than for juveniles (0.86), and we estimated a population density of 13-14 turtles/stream kilometer. The survival estimates for adult M. temminckii are among the highest of all freshwater turtle species reported in the literature. We used the empirical demographic parameters described here and a literature review to build an updated population model for M. temminckii; the model estimated a finite rate of population increase consistent with a growing population (k ¼ 1.036) at Spring Creek, and population viability analysis found the population growing over the next 50 yr in 100% of simulations. Application of our model to published survival estimates from two impacted western populations indicated a declining population (k ¼ 0.563) with a high risk of extirpation in Oklahoma and a population with a slow rate of decline (k ¼ 0.978) but approaching stability in Arkansas. Simulations identified combinations of survival values which generate viable populations and also characterized population structure resulting from viable scenarios. This is the first study to document a stable and viable population of Macrochelys. We suggest that the population parameters described at Spring Creek are the best approximation of reference demographic conditions for Macrochelys to date, and this study provides a general framework applicable for large, long-lived, endangered turtle species for which demographic data are unavailable.

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Evaluating recent taxonomic changes for alligator snapping turtles (Testudines: Chelydridae)

Cited by 19 publications

References 9 publications

A Review of the Fossil Record of Turtles of the CladePan-Chelydridae

A Review of the Fossil Record of Turtles of the CladePan-Chelydridae

Time and environment explain the current richness distribution of non‐marine turtles worldwide

Establishing Reference Demography for Conservation: A Case Study ofMacrochelys temminckiiin Spring Creek, Georgia

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