Topic
Drymarchon
About: Drymarchon is a research topic. Over the lifetime, 14 publications have been published within this topic receiving 151 citations.
Papers
TL;DR: Krysko et al. as discussed by the authors used DNA sequence data to reveal two genetic lineages of Drymarchon couperi, the Atlantic lineage containing specimens from southeastern Georgia and eastern peninsular Florida, and the Gulf Coast lineage contained specimens from western and southern peninular Florida as well as western Florida, southern Alabama, and southern Mississippi.
Abstract: Krysko et al. (2016a) used analyses of DNA sequence data to reveal two genetic lineages of Drymarchon couperi. The Atlantic lineage contained specimens from southeastern Georgia and eastern peninsular Florida, and the Gulf Coast lineage contained specimens from western and southern peninsular Florida as well as western Florida, southern Alabama, and southern Mississippi. In a second paper Krysko et al. (2016b) analyzed morphological variation of the two lineages, which allowed them to restrict D. couperi to the Atlantic lineage and to describe the Gulf Coast lineage as a new species, Drymarchon kolpobasileus. This taxonomic discovery was remarkable for such a large, wide-ranging species and was notable for its impact on conservation. Because of population declines, particularly in western Florida, southern Alabama, and southern Mississippi, D. couperi (sensu lato) was listed as Threatened under the Endangered Species Act (United States Fish and Wildlife Service 1978, 2008) and repatriation of the species to areas where it had been extirpated was listed as a priority conservation goal (United States Fish and Wildlife Service 1982, 2008). Such repatriation efforts were attempted in Alabama, Florida, Georgia, and South Carolina, starting in 1977 (Speake et al. 1987), but failed to create viable populations, likely because too few snakes were released at too many sites (Guyer et al. 2019; Folt et al. 2019a). A second attempt at repatriation was started in 2010 and concentrated on release of snakes at a single site in Alabama (Stiles et al. 2013). However, Krysko et al. (2016a) criticized this repatriation effort because it appeared to involve release of D. couperi (sensu stricto) into the geographic region occupied by D. kolpobasileus (as diagnosed in Krysko et al. 2016b).
33 citations
TL;DR: Examining Drymarchon couperi, a large, federally-protected species in North America that was recently divided into two species, is examined, and inconsistent patterns between mitochondrial and nuclear DNA are suggested to be driven by high dispersal of males relative to females.
Abstract: Accurate species delimitation and description are necessary to guide effective conservation of imperiled species, and this synergy is maximized when multiple data sources are used to delimit species. We illustrate this point by examining Drymarchon couperi (Eastern Indigo Snake), a large, federally-protected species in North America that was recently divided into two species based on gene sequence data from three loci and heuristic morphological assessment. Here, we re-evaluate the two-species hypothesis for D. couperi by evaluating both population genetic and gene sequence data. Our analyses of 14 microsatellite markers revealed 6-8 genetic population clusters with significant admixture, particularly across the contact zone between the two hypothesized species. Phylogenetic analyses of gene sequence data with maximum-likelihood methods suggested discordance between mitochondrial and nuclear markers and provided phylogenetic support for one species rather than two. For these reasons, we place Drymarchon kolpobasileus into synonymy with D. couperi. We suggest inconsistent patterns between mitochondrial and nuclear DNA are driven by high dispersal of males relative to females. We advocate for species delimitation exercises that evaluate admixture and gene flow in addition to phylogenetic analyses, particularly when the latter reveal monophyletic lineages. This is particularly important for taxa, such as squamates, that exhibit strong sex-biased dispersal. Problems associated with over-delimitation of species richness can become particularly acute for threatened and endangered species, because of high costs to conservation when taxonomy demands protection of more individual species than are supported by accumulating data.
29 citations
1 Jan 2007
28 citations
Journal Article•
TL;DR: A number of studies have found that groups of populations formerly regarded as subspecies of a single species in reality represent divergent and in-dependently evolving lineages, which should be recognised at the species level.
Abstract: INTRODUCTIONThe last two decades have seen a revival in interest inthe alpha taxonomy of many groups of animals. This re-surgent interest can be traced to several factors,including the increasing awareness of the extreme rateof extinction caused by human activities, the develop-ment of new molecular (e.g. Avise, 1994) and numerical(e.g. Thorpe, 1976, 1987) methods for the investigationof species-level systematics, and a widespread shiftfrom process-based species concepts (in particular, thebiological species concept) towards historical con-cepts, such as the evolutionary and phylogeneticspecies concepts (Wiley, 1981; Cracraft, 1989; Frost &Hillis, 1990). In general, the current trend has been to-wards the recognition of clearly distinct taxa as separatespecies rather than subspecies, without undue concernfor often untestable questions of reproductive compat-ibility.During this paradigm shift, it has become apparentthat the use of the biological species concept – whichgroups similar populations together on the basis of es-tablished or assumed reproductive compatibility – islikely to result in a serious underestimate of biologicaldiversity and a misrepresentation of phylogeny(Cracraft, 1989). A number of studies have found thatgroups of populations formerly regarded as subspeciesof a single species in reality represent divergent and in-dependently evolving lineages, which should be giventaxonomic recognition at the species level.In many long-recognized, widespread, polytypic spe-cies, conspecificity of the various subspecies has neverbeen investigated, but has become fixed in the literaturethrough a three-stage process. The three stages are aninitial plethora of species described independently forvarious “forms” (usually in the 19
27 citations
TL;DR: Molecular data support the initial hypothesis that D. couperi is split into two distinct genetic lineages that correspond to historical biogeography and sea level changes in peninsular Florida and illustrate a common biogeographic distributional break previously identified for other plants and animals.
20 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2019 | 2 |
| 2018 | 2 |
| 2016 | 2 |
| 2012 | 1 |
| 2007 | 1 |
| 2005 | 1 |