Anolis

Moreno-Arias, Rafael A. & Calderón-Espinosa, Martha L., 2016, Patterns of morphological diversification of mainland Anolis lizards from northwestern South America, Zoological Journal of the Linnean Society 176 (3), pp. 632-647 : 643-644

ECOLOGY OF ANOLIS ASSEMBLAGES OF NORTHWESTERN SOUTH AMERICA

Several studies have revealed relationships amongst morphology, ecology, and behaviour ( Miles & Ricklefs, 1984; Pianka, 1986). In Anolis , some morphological attributes translate into performance capability, and these capabilities constrain the ecology of anoles ( Losos, 1990a). Anole lizards are an example of ecomorphological relationships. Williams (1972) coined ecomorph as a term to define groups of anole species with similar morphology and habitat use but without close phylogenetic relationships. Later, Losos (1990a, c) demonstrated quantitatively the links amongst morphological, ecological, and behavioural traits in Greater Antilles anoles. Owing to the evolution of subdigital lamellae, anoles are mostly arboreal but several species also show diverse microhabitat uses, and are semiarboreal, terrestrial, or semiaquatic ( Losos, 2009). Colombian anoles are not an exception and also use a wide variety of microhabitats; six morphotypes are arboreal, and the remaining four are semi-arboreal. Semiaquatic species also occur but they cannot be classified into a particular morphotype.

Although the ecology of many mainland anole species is unknown, the matches between morphotypes and ecomorphs found here permit us to infer some associations between our morphological groups and their predominant habitat use.

Giant species of MT10 and some of MT7 use mostly tree trunks in the upper strata and canopy. Anolis frenatus and Anolis punctatus seem ecologically similar to the crown-giant ecomorph from the Greater Antil- les ( Irschick et al., 1997), but A. punctatus is not enough large to be a giant anole and it also matches with the trunk-crown ecomorph. The absence of MT 10 in Amazonas can be explained because giant anole evolution was constrained by the presence of larger canopy lizards, such as Plica plica and Uracentron flaviceps , which are large lizards that use trunks of large trees ( Vitt, Zani & Avila-Pires, 1997; R. A. Moreno-Arias pers. observ. 2014). These lizards may have restricted the evolution of anoles towards giant forms owing to niche incumbency or a priority effect.

In addition, several species of MT8 use shrubs or tree trunks and branches in the canopy and understorey strata, but species of MT6 are more common in the understorey to herbaceous strata. These two morphotypes apparently do not have a Caribbean ecomorph counterpart, although Anolis biporcatus and Anolis chocorum are recognized as crown-giants ( Castro-Herrera, 1988; Losos, 2009).

Small anoles of MT3 live in the lowlands, and use mostly tree trunks from the understorey to the canopy ( Table S1). Whereas Anolis anchicayae , Anolis chloris , Anolis ortonii and Anolis peraccae resemble the trunkcrown ecomorph, Anolis pentaprion was previously recognized as twig anole ( Irschick et al., 1997; Losos, 2009). For the latter two species, recent ecological data (R. A. Moreno-Arias, unpubl. data) plus their lichenose colour pattern indicate that these species resemble the Caribbean trunk ecomorph more than the trunkcrown ecomorph.

Small and tiny anoles of MT4 are found from midmountain to Paramos regions, and use branches and twigs from the understorey to the canopy ( Table S1). This group shows a greater similarity to a Caribbean ecomorph than does any other group. In the same vein as other studies ( Schaad & Poe, 2010), our results also identified MT4 species as twig anoles.

Species of MT1 use mostly trunks and branches of small trees, shrubs, and herbs of the understorey or herbaceous strata, but rarely use the ground ( Table S1). Only two species ( Anolis auratus and Anolis fuscoauratus ) have been recognized by other authors as grass-bush anoles ( Irschick et al., 1997; Schaad & Poe, 2010).

Species of MT2 inhabit the ground, leaf litter, and log falls, and sometimes use shrubs and herbs ( Table S1). Schaad & Poe (2010) identified Anolis granuliceps as a member of the grass-bush ecomorph despite it was the species morphologically furthest from members of the grass-bush group. Irschick et al. (1997) showed that Anolis trachyderma is the morphological centroid of the trunk-ground morphotype, but its nearest neighbour was a grass-bush species. Matching a Caribbean ecomorph for the MT2 species is complicated, and requires more quantitative data of their ecology; however, we suggest that species of MT2 correspond to a unique mainland ecomorph owing to their greater preference for the ground compared with the other morphotypes.

MT5 anoles use tree trunks, shrubs, and ground in nearly the same proportions ( Table S1). Anolis scypheus grouped within the trunk-ground ecomorph ( Irschick et al., 1997), and the ecology of the remaining species suggests that they are also trunk-ground anoles.

Large anoles of MT9, despite their shared morphological attributes, show disparate microhabitat uses. Anolis fraseri uses tree trunks in the canopy like species of MT10; A. mirus is similar to species of MT6 that also use branches in the understorey, whereas A. onca is a typical anole of xerophytic vegetation near beaches that uses bushes, shrubs, and the ground, similar to species of MT1. It is interesting that MT5 anoles possess the most robust bodies and some authors have observed very aggressive behaviour in A. fraseri and A. mirus (F. Castro-Herrera & S. Ayala, unpubl. data), which leaves the relationship between body robustness and aggressive behaviour occurring in this clade as an open hypothesis to test.

Semiaquatic anoles do not constitute a morphologically distinctive group on the basis of the characters used here. Instead, three species ( Anolis lynchi , Anolis poecilopus , and Anolis rivalis ) were assigned to MT5 and the other two species ( Anolis macrolepis and Anolis maculigula ) to MT1 and MT8, respectively. All semiaquatic species use vegetation of herbaceous and understorey strata surrounding streams and pools, but also use other microhabitats. Anolis macrolepis is also found on the ground, whereas A. maculigula , A. poecilopus , and A. rivalis use rocks and boulders in streams and pools ( Williams, 1984; Miyata, 1985; F. Castro-Herrera & S. Ayala, unpubl. data).

Therefore, semiaquatic anoles support the idea that the semiaquatic habit can be acquired through a variety of body plans. Another possibility is that other traits not evaluated here, such as tail shape (related to swimming performance), could be a link amongst species exhibiting a semiaquatic ecology, as suggested by Leal, Knox & Losos (2002). Studies on performance and morphology will give some clues to defining semiaquatic anoles as an ecomorph type.