A review of iguanian and anguimorph lizard genitalia (Squamata: Chamaeleonidae; Varanoidea, Shinisauridae, Xenosauridae, Anguidae) and their phylogenetic significance: comparisons with molecular data sets

Abstract

We compare phylogenetic hypotheses for iguanian (chameleonids) and anguimorph lizard groups (varanoids, xenosauroids, anguids) which were generated from analyses of genital (hemipenial) morphology, with recent molecular phylogenetic approaches towards the same groups. Taxa with infraspecific communication by means of visible, sexually dimorphic epigamic characters usually have less diverse genital structures than taxa with less developed visible epigamic characters but with a more highly developed chemical intersexual communication. Generally, it turned out in the cases considered here, that phylogenetic hypotheses based on hemipenial characters coincide much better with molecular-genetic phylogenies than with earlier concepts based solely on external morphology. It seems that genital morphological characters are phylogenetically more informative -on both the species and the supraspecific level -than external morphological characters at least in these examples, because the former seem not to be affected by environmental selective pressures but seem to be only subject to sexual selection. Our data suggest that sexual selective pressure on genital structural diversity is higher the less sexually dimorphic, optical cues for infraspecific communication have evolved. They further suggest a correlation with the mating system (single versus multiple matings).

Genitals evolve faster than other traits in Anolis lizards

“…Our results provide quantitative support for the common presumption that male genitalia are more variable and evolve more rapidly than nongenital morphological traits (Arnqvist, ; Hosken & Stockley, ; Eberhard, , ). While this conclusion has previously been drawn largely from the fact that genitalia tend to be species‐specific and diagnostic of otherwise cryptic species, (Böhme & Ziegler, ; Eberhard, ), we corroborate it using modern phylogenetic comparative analyses across a diverse genus. We found that in Caribbean anoles, hemipenial traits evolve approximately six times faster than nongenital traits (Table ), with the three genital traits sharing a similar and high rate.…”

Opening a box of cryptic taxa - the first review of the North African desert lizards in the Trapelus mutabilis Merrem, 1820 complex (Squamata: Agamidae) with descriptions of new taxa

“…Thus, other diagnostic characters will allow the identification of species throughout the year. For example, genital morphology is a useful taxonomic character in lizards (Branch, 1981; Klaver & Böhme, 1986; Böhme, 1988; Böhme & Ziegler, 2008).…”

Hemipenes in females of the mexican viviparous lizard Barisia imbricata (Squamata: Anguidae): an example of heterochrony in sexual development

“…In the case of lizards, the hemipenes have developed species‐specific morphological characteristics in shape, size, and ornamentation as a result of an evolutionary process. (Kluge ; Arnol ; Shea and Reddacliff ; Bômhe and Ziegler ; Gredler et al , ). This suggests that this structure has a high degree of plasticity in the saurians and, therefore, potential for evolution (Gredler ).…”