Origins and biogeography of the Anolis crassulus subgroup (Squamata: Dactyloidae) in the highlands of Nuclear Central America

Abstract

BackgroundRecent studies have begun to reveal the complex evolutionary and biogeographic histories of mainland anoles in Central America, but the origins and relationships of many taxa remain poorly understood. One such group is the Anolis (Norops) crassulus species subgroup, which contains ten morphologically similar highland taxa, the majority of which have restricted distributions. The nominal taxon A. crassulus has a disjunct distribution from Chiapas, Mexico, through Guatemala, in the highlands of El Salvador, and in the Chortís Highlands of Honduras. We test the relationships of these species using multiple mitochondrial and nuclear loci in concatenated and multispecies coalescent frameworks, in an effort to both resolve long-standing taxonomic confusion and present new insights into the evolution and biogeography of these taxa.ResultsSequences of multiple mitochondrial and nuclear loci were generated for eight of the ten species of the Anolis crassulus species subgroup. We analyzed phylogenetic relationships and estimated divergence times and ancestral ranges of the subgroup, recovering a monophyletic subgroup within Anolis. Within the nominal taxon Anolis crassulus, we recovered multiple genetically distinct lineages corresponding to allopatric populations, and show that the Chortís Highland lineage split from the others over 13 MYA. Additionally, distinct mitochondrial lineages are present within the taxa A. heteropholidotus and A. morazani, and importantly, samples of A. crassulus and A. sminthus previously used in major anole phylogenetic analyses are not recovered as conspecific with those taxa. We infer a Chortís Highland origin for the ancestor of this subgroup, and estimate cladogenesis of this subgroup began approximately 22 MYA.ConclusionsOur results provide new insights into the evolution, biogeography, and timing of diversification of the Anolis crassulus species subgroup. The disjunctly distributed Anolis crassulus sensu lato represents several morphologically conserved, molecularly distinct anoles, and several other species in the subgroup contain multiple isolated lineages.Electronic supplementary materialThe online version of this article (doi: 10.1186/s12862-017-1115-8) contains supplementary material, which is available to authorized users.

Cryptic Diversity, but to What Extent? Discordance Between Single-Locus Species Delimitation Methods Within Mainland Anoles (Squamata: Dactyloidae) of Northern Central America

“…In some cases, however, it is clear that the analyses over-split taxa. As in Blair and Bryson (2017)’s analyses of Phrynosoma lizards, our bPTP analyses produced unreasonable delimitations with wide confidence intervals; some of these clusters do not reflect relationships as understood with better molecular sampling (Hofmann and Townsend, 2017) and others were separated into numerous lineages despite little-to-no divergence between them (e.g., N. cupreus; Figure 3). bPTP is known to be sensitive to different mutation rates, but unlike in the simulated data of Dellicour and Flot (2018), here it produced the least-accurate delimitations.…”

“…As such, we refer to the monophyletic grouping of beta anoles as Norops (sensu Nicholson et al, 2018), while recognizing the criticisms of the multiple-genera taxonomy (e.g., Poe, 2013). All native, mainland Norops in the Chortís Block are beta anoles and members of clade Draconura [Poe et al, 2017 ( auratus group of Nicholson et al, 2012)], one of the three clades within Norops , all of which share the synapomorphy of anterolaterally directed transverse processes on their caudal vertebrae (Etheridge, 1959; Nicholson, 2002) as well as numerous molecular characters (Nicholson et al, 2012; Poe et al, 2017).…”

“…Anoles (Squamata: Dactyloidae) are particularly strong representatives of the Chortís Block’s squamate diversity, the region’s high levels of endemism, and the need for increased study and conservation work. As currently considered, thirty-eight species of anole lizards are native to the mainland Chortís Block, 20 (52.6%) of which are considered endemic (Table 1; Townsend, 2014; McCranie and Köhler, 2015; Köhler et al, 2016; Hofmann and Townsend, 2017, 2018). Two additional species, Anolis allisoni and Norops sagrei , have been introduced to the northern coast of mainland Honduras (McCranie and Köhler, 2015).…”

Phylogenetics of Ogyges Kaup and the biogeography of Nuclear Central America (Coleoptera, Passalidae)

“…With few exceptions (e.g. Wake and Lynch 1976 , Johnson 1989 , Campbell and Frost 1993 , Townsend 2014 , Pérez-Consuegra and Vásquez-Domínguez 2015 , Hofmann and Townsend 2017 ), its biotic relevance has been overlooked by biogeographers, and phylogenetic analyses of taxa endemic to this area are scarce. The biota has been studied as part of North American, Neotropical, Mexican, Middle American, Mesoamerican or Central American regions, and often is considered a “mixture” of North and South American elements, obscuring the in situ diversification of supraspecific taxa.…”

“…The biota has been studied as part of North American, Neotropical, Mexican, Middle American, Mesoamerican or Central American regions, and often is considered a “mixture” of North and South American elements, obscuring the in situ diversification of supraspecific taxa. Nuclear Central America is particularly speciose in endemic taxa such as plethodontid salamanders ( Campbell et al 2010 , Townsend 2014 , Rovito et al 2015 ), cricetid mice ( Conroy et al 2001 ; Gutiérrez-García and Vásquez-Domínguez 2012 , 2013 ; Ordóñez-Garza et al 2014 ; Pérez-Consuegra and Vásquez-Domínguez 2015 ), squamates ( Campbell and Frost 1993 , Campbell and Brodie 1999 , Castoe et al 2003 , Hasbún et al 2005 , Townsend et al 2013 , Hofmann and Townsend 2017 ) and beetles ( Schuster 1993 , Micó et al 2006 , Cano 2014 , Sokolov and Kavanaugh 2014 ).…”