History and the Global Ecology of Squamate Reptiles

Abstract

The structure of communities may be largely a result of evolutionary changes that occurred many millions of years ago. We explore the historical ecology of squamates (lizards and snakes), identify historically derived differences among clades, and examine how this history has affected present-day squamate assemblages globally. A dietary shift occurred in the evolutionary history of squamates. Iguanian diets contain large proportions of ants, other hymenopterans, and beetles, whereas these are minor prey in scleroglossan lizards. A preponderance of termites, grasshoppers, spiders, and insect larvae in their diets suggests that scleroglossan lizards harvest higher energy prey or avoid prey containing noxious chemicals. The success of this dietary shift is suggested by dominance of scleroglossans in lizard assemblages throughout the world. One scleroglossan clade, Autarchoglossa, combined an advanced vomeronasal chemosensory system with jaw prehension and increased activity levels. We suggest these traits provided them a competitive advantage during the day in terrestrial habitats. Iguanians and gekkotans shifted to elevated microhabitats historically, and gekkotans shifted activity to nighttime. These historically derived niche differences are apparent in extant lizard assemblages and account for some observed structure. These patterns occur in a variety of habitats at both regional and local levels throughout the world.

Genetic evidence for co-occurrence of chromosomal and thermal sex-determining systems in a lizard

“…This species differs from B. duperreyi not only in habitat type (alpine versus desert) but also in the chromosomal sex-determining system (XY versus ZW ), the temperature extreme which overrides genotypic sex (cold versus hot), and which sex of offspring is overproduced under those extreme conditions (sons versus daughters: see Quinn et al 2007). Clearly, a sex-determining system that incorporates simultaneous genotypic sex determination and temperature-dependent sex determination either is basal to lizard phylogeny (these two lineages probably separated ca 180 Myr ago: Vitt et al 2003), or has evolved at least twice. Regardless, current paradigms underestimate the complexity of vertebrate sex-determining systems; offspring sex in many squamate reptiles may be the end result of multiple factors operating simultaneously (and interactively) within single populations (as they do in many invertebrates: Bull 1983; Kozielska et al 2006).…”

Intercontinental community convergence of ecology and morphology in desert lizards

“…Similarly, the Gekkonidae and Scincidae are diverse in Australia and Africa, but depauperate in North America. Because lizard families tend to be ecologically distinctive Vitt et al 2003;Vitt & Pianka 2005), it is thus not surprising that the structure of lizard communities on different continents varies so greatly (for another herpetological example see Cadle & Greene 1993).…”

Diet of the lizard Liolaemus occipitalis in the coastal sand dunes of southern Brazil (Squamata-Liolaemidae)

“…A high frequency of ants was also observed in the stomach, and ants were the most frequently identified food item. Ants are associated with the diet of sit-and-wait foragers, but termites are associated with widely active foragers (Huey and Pianka, 1981;Magnusson et al, 1985;Vitt et al, 2003;Silva and Araújo, 2008). The high mobility and local abundance of ants favors encounters between these insects and ambush predator lizards, which facilitates the capture of this type of prey.…”

“…Species of the genus Liolaemus, such as L. cuyanus CEI and SCOLARO, (1980), (Azócar andAcosta, 2011), L. pseudoanomalus BURMEISTER, (1981), (Kozykariski et al, 2011), L. bibronii (BELL, 1843) (Belver and Avila, 2001, L. wiegmannii (DUMÉRIL & BIBRON, 1837) (Aun et al, 1999), L. koslowskyi ETHERIDGE, 1993, (Aun and Martori, 1998, L. boulengeri KOSLOWSKY, 1898, (Acosta et al, 1996), L. darwini (BELL, 1843), (Avila and Acosta, 1993;Videla, 1983) and L. lutzae (Rocha, 1989), and lizards of the genus Tropidurus also exhibit a preference for ants (Van Sluys, 1993, 1995Vitt and Carvalho, 1995). According to Vitt et al (2003), Iguanid lizards consume larger proportions of ants and other Hymenoptera because these lizards occupy a different microhabitat than the Scleroglossa lizards, which consume larger proportions of termites and spiders and avoid the consumption of prey with toxic chemical defenses.…”