Geographical structure and cryptic lineages within common green iguanas, Iguana iguana

Abstract

Aim Our aim was to investigate genetic structure in Neotropical populations of common green iguanas (Iguana iguana) and to compare that structure with past geological events and present barriers. Additionally, we compared levels of divergence between lineages within Iguana with those within closely related genera in the subfamily Iguaninae. Location Neotropics. Methods DNA sequence data were collected at four loci for up to 81 individuals from 35 localities in 21 countries. The four loci, one mitochondrial (ND4) and three nuclear (PAC, NT3, c‐mos), were chosen for their differences in coalescent and mutation rates. Each locus was analysed separately to generate gene trees, and in combination in a species‐level analysis. Results The pairwise divergence between Iguana delicatissima and I. iguana was much greater than that between sister species of Conolophus and Cyclura and non‐sister species of Sauromalus, at both mitochondrial (mean 10.5% vs. 1.5–4%, respectively) and nuclear loci (mean 1% vs. 0–0.18%, respectively). Furthermore, divergences within I. iguana were equal to or greater than those for interspecific comparisons within the outgroup genera. Phylogenetic analyses yielded four strongly supported, geographically defined mitochondrial clades (3.8–5% divergence) within I. iguana. Three of the four clades were found using PAC (0.18–1.65% divergence) and two using NT3 (0.6% divergence) alone. The primary divergence, recovered in three polymorphic loci, was between individuals north and south of the Isthmus of Panama. The southern group was differentiated into clades comprising individuals on either side of the northern Andes, using both PAC and ND4. Main conclusions Deep genetic divergences were found within I. iguana that are congruent with past and current geological barriers. These divisions are greater than sister species comparisons in other Iguaninae genera, indicating the possible presence of cryptic species. Geological changes from the mid‐Miocene through the Plio‐Pleistocene have shaped the pattern of divergence in I. iguana. The uplift of the northern Andes presented a barrier between South American I. iguana populations by 4 Ma. Populations north of the Isthmus of Panama form a clade that is distinct from those to the south, and may have expanded northwards following the closing of the Isthmus of Panama 2.5 Ma.

Genetic structure of Tupinambis teguixin (Squamata: Teiidae), with emphasis on Venezuelan populations.

“…Stephen et al (2013) investigated the genetic structure of the common iguana (Iguana iguana), in relation to several geographic barriers, including the MA and found profound divergence consistent with the barriers. Further, they suggest the presence of cryptic species, although further sampling would be required to confirm this possibility.…”

“…Additionally, there is evidence that both barriers have affected the genetic structure and/or the distribution of several taxa, including capybaras (Mones, 1991), bats (Romero, 2003), snakes (Schargel, Fuenmayor, Barros, Péfaur, & Navarrete, 2007;Scartozzoni, Trevine, & Germano, 2010), lizards (Miralles et al, 2009;Stephen, Reynoso, Collett, Hasbun, & Breinholt, 2013), turtles (Vargas-Ramírez et al, 2012, Vargas-Ramírez, Carr, & Fritz, 2013 and birds (Pereira & Baker, 2004). Using these conditions, both the Paleogeographic and the Riverine hypothesis can be tested.…”

Sperm competitive advantage of a rare mitochondrial haplogroup linked to differential expression of mitochondrial oxidative phosphorylation genes

“…Unlike temperate zone species, tropical species often exhibit high levels of mitochondrial DNA sequence variation across small spatial scales even in the presence of gene flow (Stephen, Reynoso, Collett, Hasbun, & Breinholt, 2013;Strutzenberger, Brehm, & Fiedler, 2011;Wilcox, Hugg, Zeh, & Zeh, 1997). The introgression of divergent mitochondrial haplotypes provides an opportunity to investigate the micro-and macroevolutionary consequences of sexually asymmetric selection acting on mitochondria in natural populations.…”

Osteological Differentiation of theIguanaLaurenti, 1768 (Squamata: Iguanidae) Species:Iguana iguana(Linnaeus, 1758) andIguana delicatissimaLaurenti, 1768, with some Comments on their Hybrids

“…It probably was introduced to the Lesser Antilles during modern times from both South and Central America, but this is obscured by possible endemic forms that exist on Saba, Montserrat, and Saint Lucia islands (Malone and Davis, 2004;Breuil, 2013;Stephen et al, 2013). Iguana iguana and I. delicatissima are morphologically and molecularly distinct yet can hybridize (Day and Thorpe, 1996;Malone and Davis, 2004;Breuil, 2013;Stephen et al, 2013). The common assumption is that hybridization has endangered the survival of I. delicatissima following island introduction of the continental I. iguana (Breuil, 2002;Day et al, 2000;Breuil, 2009;Lorvelec et al, 2011;Knapp et al, 2014).…”

“…The discovery of a possibly ancient, introduced I. iguana population in the Lesser Antilles at Montserrat, St. Lucia, and Saba, however, and the weak genetic diversity of the I. delicatissima populations among islands, make the island colonization and evolution scenario of these two iguanas difficult to understand. Approaching such questions can be done using genetic data (Malone and Davis, 2004;Stephen et al, 2013;Valette et al, 2013), but subfossil remains preserved in archaeological and paleontological deposits also can provide direct evidence of past iguana populations to suggest new hypotheses or test genetic assumptions. Such material is available in the Lesser Antilles, where there exist dozens of archaeological sites of pre-Columbian age that contain iguana remains (Grouard, 2001(Grouard, , 2007(Grouard, , 2010(Grouard, , 2013.…”