Figure - uploaded by Matthew R Graham
Content may be subject to copyright.
Map depicting the approximate distributions of the two foxsnake mtDNA lineages as hypothesized from this study. The light shaded area represents the range of Pantherophis ramspotti, and the dark shaded area represents the range of P. vulpinus. The Mississippi River is a historical barrier yet either side has haplotypes from the other side (the hatched area).
Source publication
As currently understood, there are two species of foxsnakes (Eastern Foxsnake, Pantherophis gloydi Conant and Western Foxsnake, P. vulpinus Baird and Girard) that are separated by a large geographic disjunction that encompasses almost all of Michigan, eastern Indiana, and eastern Ohio. Phylogenetic analysis of mtDNA data of individuals from through...
Context in source publication
Similar publications
Phylogeographic studies of Holarctic birds are challenging because they involve vast geographic scale, complex glacial history, extensive phenotypic variation, and heterogeneous taxonomic treatment across countries, all of which require large sample sizes. Knowledge about the quality of phylogeographic information provided by different loci is cruc...
Citations
... Since 2000, the number of species of Lampropeltis has been recommended for increase from 9 to 24 (Bryson et al., 2005;Pyron and Burbrink, 2009b;Myers et al., 2013;Ruane et al., 2014;McKelvy and Burbrink, 2017). The clade that is now Pantherophis was increased from 3 species to 9 (Burbrink, 2001;Burbrink, 2002;Crother et al., 2011). Pituophis was increased from 4 to 7 (Crother, 2000;Wallach et al., 2014). ...
Accurate representation of lineage diversity through complete taxon sampling is crucial to understanding the evolution of biodiversity, particularly when using molecular phylogenetics to estimate evolutionary relationships. In this interest, taxonomic diversity is often used as a proxy for lineage diversity even though the two concepts are not synonymous. We explore this within the snake tribe Lampropeltini which includes some of the most conspicuous and heavily studied snakes in North America. Both the taxonomy and hypothesized relationships within this tribe have been in flux. The number of species has increased from 23 to 51 over the last thirty years, predominately within three of the nine genera (Lampropeltis, Pantherophis, Pituophis). The remaining six depauperate genera (Arizona, Bogertophis, Cemophora, Pseudelaphe, Rhinocheilus, and Senticolis) have been poorly represented in phylogenetic studies. To estimate evolutionary relationships and determine if the dichotomy in depauperate and speciose genera within Lampropeltini is a function of taxon sampling or truly represents the lineage diversity, we estimated the phylogeny of this group using nuclear and mitochondrial loci in a concatenated and coalescent framework with the largest sampling of the six depauperate genera to date. In addition, we estimated the divergence dates among the genera to assess whether the instability of Lampropeltini phylogenetic relationships is due to an adaptive radiation. While some nodes still remain unresolved, the generic-level relationships we recovered agree with those of a recent next-generation study that used a much larger set of loci for fewer individuals. We also tested two putative species, Arizona pacata and Pseudelaphe phaescens, for the first time phylogenetically and find evidence that they are distinct lineages. Overall, we find that the taxonomic and genetic diversity are not correlated in Lampropeltini and that representing putative diversity in phylogenies will lead to a better estimate of evolutionary histories, especially in groups with complex radiations.
... Like C. c. coccinea and C. c. copei, C. c. lineri is small, fossorial, and exhibits facultative oophagy, but C. c. lineri differs from other C. coccinea in color pattern and lepidosis: C. c. lineri has black dorsal bands that extend laterally to the third, fourth, or fifth scale row (between midbody and tail), whereas other C. coccinea have black dorsal bands that extend laterally to the first or second scale row, and C. c. lineri usually have more ventral scales than other C. coccinea. Additionally, mitochondrial divergence between C. c. lineri and other C. coccinea (~4%) is similar to levels of divergence observed between other snake species (Burbrink et al., 2000;Crother et al., 2011). We choose not to recognize any Cemophora subspecies, elevating C. c. lineri to a full species (see Systematic Account) according to the general lineage species concept (de Queiroz, 2007), while restricting C. coccinea to include populations formerly assigned to C. c. coccinea and C. c. copei. ...
Scarlet Snakes (Cemophora coccinea) are monotypic, poorly studied, semifossorial habitat specialists from southeastern United States that traditionally include three subspecies based on color pattern and morphology. We sequenced two mitochondrial and two nuclear loci for 62 individuals from across the species range, and analyzed data with the use of parsimony and Bayesian phylogenetic methods to test a previously proposed phylogenetic hypothesis for C. coccinea. Our results suggest two Pliocene or Pleistocene refugia for Cemophora, one in southern Texas, and the other in the region extending from southeastern Louisiana through Florida. In light of our results we elevate Cemophora coccinea lineri to a full species, C. lineri, that differs from C. coccinea sensu stricto genetically and phenotypically.
... In particular, North America is an important region for understanding Pleistocene impacts. At times, massive ice sheets (e.g., Laurtentide Ice Sheet up to 3.2 km [2 miles] thick) covered large areas of the upper North American continent (Holman, 2000) and most land areas were influenced by glacial events that facilitated lineage diversifications in many plants and animals (Avise, 1994(Avise, , 2000(Avise, , 2004Avise et al., 1987Johnson and Cicero, 2004;Soltis et al., 2006;Weir and Schluter, 2007;Pyron and Burbrink, 2009;Crother et al., 2011). Additionally, multiple species illustrating the same or similar biogeographic distributional pattern suggests that they might have a shared or similar evolutionary history. ...
... Based on skeletal features, Holman (2000:312) hypothesized that ''no new species of snakes evolved during the Pleistocene." However, skeletal characters appear to evolve slower than other characters (i.e., DNA, scalation, color pattern) and recent mtDNA studies illustrate that numerous snake species have evolved after the Pliocene (e.g., this study; Guiher and Burbrink, 2008;Burbrink et al., 2008;Fontanella et al., 2008;Pyron and Burbrink, 2009;Crother et al., 2011). Among our Drymarchon Atlantic and Gulf lineages, there are 12 fixed genetic differences (thus they are diagnosable using molecules), significant genetic differentiation, strong levels of population genetic structure, and low migration rate. ...
... There is a conspicuous omission of direct reference to the existence of parallel fifth and sixth checklists produced by the CNAH. There are a number of differences in recognition of taxa, the most notable [and rejected] in the SSAR list is Collins and Taggart (2008) resurrection of generic names for Fox Snakes (Mintonius) [see Crother et al. 2011] and "Woodland Rat Snakes" (Scotophis) [see Pyron et al. 2009] which were accepted in Collins and Taggart (2009) but remain included in Pantherophis in the SSAR list. ...
Species delimitation is a first step for realizing the extent of biodiversity and is relevant for all downstream applications in biology. The production of large genome-scale datasets for non-model organisms combined with the development of methodological tools have allowed researchers to examine fine-scale processes of speciation such as timing of origin, degree of migration, population-size changes, selection, drift, and recombination. Studies using reptiles and amphibians have, in part, paved the way for the development and use of such methods for exploring speciation and delimitation. While these methodologies have improved our understanding of processes of diversification, researchers are far from agreeing upon a set of criteria to delimit species. In cases where genetic lineages are discovered that are unique to geographic areas, researchers usually agree that two entities exist. Disagreement about taxonomic status often centers on the degree of reproductive isolation between taxa and probability of remaining distinct. However, reproductive isolation is frequently inferred without examining gene flow, understanding the nature of hybrid zones, or determining the amount and type of introgression. Here, we review some of the vexing problems for delimiting reptiles and amphibians, which include isolation by distance, gene flow and differential allelic introgression, hybrid zone dynamics, and the nature of genomic islands of divergence. We also respond to recent literature criticizing model-based species delimitation in North American snakes in the context of these methodological advancements and address how scientists can move forward with studies on speciation.