Molecular systematics and historical biogeography of the genusGerrhonotus(Squamata: Anguidae)

Abstract

Aim: Multiple geological and climatic events have created geographical or ecological barriers associated with speciation events, playing a role in biological diversification in Mexico. Here, we evaluate the influence of Neogene geological events and of Pleistocene climate change in the diversification of the genus Gerrhonotus using molecular dating and ancestral area reconstruction. Location: Mexico and south-central United States.Methods: A multilocus sequence dataset was generated for 86 individuals of Gerrhonotus from most Mexican biogeographical provinces and belonging to five of the seven currently recognized species, as well as two putative undescribed species. Phylogeographical structure was explored using Poisson-Tree-Processes molecular species delimitation. Divergence events were estimated based on the fossil record using a relaxed uncorrelated lognormal clock. Ancestral areas were estimated at divergence events across the tree using a probabilistic Bayesian approach.Results: Extensive geographical structure was evident within three well-supported clades. These clades probably diverged from each other in the early to mid-Miocene, and their divergence was followed by six divergences in the late Miocene and eight divergences in the Pliocene. The ancestral origin of Gerrhonotus with keeled dorsal scales (keeled-scale Gerrhonotus) was reconstructed to be across the Pacific Coast Province. Our phylogenetic analyses did not support the monophyly of Gerrhonotus. Main conclusions: Miocene and Pliocene geomorphology, perhaps in conjunction with climate change, appears to have induced allopatric divergence on a relatively small spatial scale in this genus. The late Miocene-Pliocene reduction in the highlands along the Tehuantepec fault probably created a large marine embayment that led to an early divergence in a clade of Gerrhonotus. Our analysis suggests uplifting of the Trans-Mexican Volcanic Belt during this same time period resulted in additional diversification. This was followed by more recent, independent colonization events in the Pliocene from the Mexican Plateau to the Sierra Madre Oriental, Sierra Madre Occidental, Tamaulipas and Edwards Plateau provinces. A genus Gerrhonotus with the keeled-scale species in addition to Coloptychon rhombifer (= G.

Variation in the skulls of Elgaria and Gerrhonotus (Anguidae, Gerrhonotinae) and implications for phylogenetics and fossil identification

“…In our study, we treated G. lugoi and G. parvus as separate taxa within the genus Gerrhonotus pending further investigation. A paraphyletic Gerrhonotus infernalis also was previously inferred ( García-Vázquez et al, 2018a ). All specimens of G. infernalis included in our study are from Texas.…”

“…Phylogenetic analysis of molecular data suggested that G. parvus is most closely related to species in Gerrhonotus ( Conroy et al, 2005 ; Leavitt et al, 2017 ). The monophyly of Gerrhonotus and the inclusion of both G. parvus and G. lugoi within Gerrhonotus was questioned in a more recent analysis ( García-Vázquez et al, 2018a ). Those authors found that the phylogenetic position of G. parvus as sister to all Gerrhonotus , excluding G. lugoi , was not strongly supported in all analyses.…”

“…Those authors found that the phylogenetic position of G. parvus as sister to all Gerrhonotus , excluding G. lugoi , was not strongly supported in all analyses. Additionally, G. lugoi was recovered with weak support as either sister to Barisia or as an early diverging member of Gerrhonotus ( García-Vázquez et al, 2018a ). Gerrhonotus lugoi was previously included in the genus Barisia ( Waddick & Smith, 1974 ; Smith, 1986 ).…”

“…This general issue of interpreting the literature in its historical context is exacerbated by the fact that the taxonomic arrangement of species into more inclusive taxa such as genera also changes through time. Although the extant taxa included within Elgaria appear now to be stable, the same is not true for Gerrhonotus , the taxonomic makeup and monophyly of which are not yet well established ( García-Vázquez et al, 2018a ). For those reasons we made an effort here to indicate particular specimens and/or species to which our comments apply, especially for those currently placed in Gerrhonotus .…”

Physiographic and climatic events in the Chihuahuan Desert lead to the speciation and distinct demographic patterns of two sisterSceloporuslizards

“…Most of these analyzed the uplift of the Colorado Plateau‐Sierra Madre Occidental mountain range dividing the Sonoran and Chihuahuan deserts (Gámez et al, ; Jaeger et al, ; Leaché & Mulcahy, ; Rebernig et al, ; Riddle, ; Riddle & Hafner, ) , and focused either on widely distributed species (e.g., Rebernig et al, ) or several species (e.g., Leaché & Mulcahy, ; Riddle & Hafner, ). However, other physiographic and hydrographic events occurred in the CD during the Neogene and may have favored the diversification of the biota but little is known about these events (e.g., Bryson, Jaeger, Lemos‐Espinal, & Lazcano, ; García‐Vázquez, Nieto‐Montes de Oca, Bryson, Schmidt‐Ballardo, & Pavón‐Vázquez, ; Myers et al, ). The late Neogene (i.e., Pliocene) in the CD was marked by the formation of lakes established at the bottoms of the major bolsons (Axtell, ; Morafka, ).…”