Showing papers by "Jonathan B. Losos published in 2015"

Genitals evolve faster than other traits in Anolis lizards

Abstract: Male genitalia are thought to be particularly rapidly evolving morphological structures, but there have been few quantitative interspecific comparisons between the evolutionary rates of genital and nongenital traits. We characterize the morphology of hemipenes in 25 Caribbean Anolis lizard species, and compare rates of hemipenial evolution to those of traits related to ecology or visual signaling. Using phylogenetically based comparisons of rates of evolutionary divergence, we show that genital traits evolve more rapidly than nongenital traits in anoles.

Amber fossils demonstrate deep-time stability of Caribbean lizard communities

Abstract: Whether the structure of ecological communities can exhibit stability over macroevolutionary timescales has long been debated. The similarity of independently evolved Anolis lizard communities on environmentally similar Greater Antillean islands supports the notion that community evolution is deterministic. However, a dearth of Caribbean Anolis fossils—only three have been described to date—has precluded direct investigation of the stability of anole communities through time. Here we report on an additional 17 fossil anoles in Dominican amber dating to 15–20 My before the present. Using data collected primarily by X-ray microcomputed tomography (X-ray micro-CT), we demonstrate that the main elements of Hispaniolan anole ecomorphological diversity were in place in the Miocene. Phylogenetic analysis yields results consistent with the hypothesis that the ecomorphs that evolved in the Miocene are members of the same ecomorph clades extant today. The primary axes of ecomorphological diversity in the Hispaniolan anole fauna appear to have changed little between the Miocene and the present, providing evidence for the stability of ecological communities over macroevolutionary timescales.

Multiple paths to aquatic specialisation in four species of Central American Anolis lizards

Abstract: Aquatic anoles present an interesting ecomorphological puzzle. On the one hand, the link between habitat use and morphology is well established as convergent within the Caribbean anole radiation. On the other hand, aquatic anoles do not appear to form an ecomorphological group – rather, it appears that there may be several ways to adapt to aquatic habitats. We explore this issue by examining the ecology, morphology and performance of four species of Central American aquatic anoles belonging to two different lineages. Overall, we find that aquatic anoles overlap in multiple ecological and morphological dimensions. However, we do find some differences in substrate use, claw and limb morphology, and bite force that distinguish Anolis aquaticus from the other three species (A. lionotus, A. oxylophus and A. poecilopus). Our results suggest that A. aquaticus is adapted to climb on boulders, whereas the other species utilise vegetation in streamside habitats.

Correlated evolution of microhabitat, morphology, and behavior in West Indian Anolis lizards: a test of the habitat matrix model

Abstract: The habitat matrix model (HMM) explains convergence among arboreal animals as a result of the correlated evolution of morphology, locomotor mode, and habitat use. Although the HMM has generated important insights into the ecology of arboreal species, these tests have left a gap in the habitat-behavior-morphology story by focusing primarily on locomotor performance in lab and field experiments and thus failing to include data on locomotor behavior of undisturbed animals in the wild. We combined data on undisturbed locomotion, habitat use, and morphology for 31 species of arboreal lizard in the genus Anolisand used these data to test nine specific predictions arising from the HMM. We find strong support for nearly all aspects of this model. The addition of data on locomotion by undisturbed wild animals offers a more direct and compelling case for the HMM than most previous tests.

A Naturalist's Insight into the Evolution of Signal Redundancy.

Abstract: Why are animal signals so complex? This question continues to attract the interest of behavioral and evolutionary ecologists. In this Countdown article, we revisit a littleappreciated article in The American Naturalist published in 1970: “An Estimation of Redundancy and Information Content of Anole Dewlaps” by A. Stanley Rand and Ernest E. Williams (fig. 1). As part of this piece, Rand and Williams argued that signal complexity can be explained by redundancy, a mechanism by which multiple components of the signals have evolved to increase the probability of eliciting a response from an intended receiver. We highlight this work because it presents one of the earliest demonstrations of the potential benefits of applying information theory to animal communication. In addition, the study demonstrates the insights that can be gained by evaluating signal evolution at the level of the community. Even today, when both theoretical and empirical studies evaluating the potential forces leading to signal diversity have flourished, evaluations at the community level are extremely rare. More generally, in the spirit of the American Society of Naturalists, we wish to emphasize that the perspicacity of Rand and Williams resulted from the fact that their ideas were ultimately derived from a deep understanding of the natural history of their study organism. In particular, Stan Rand spent substantial time in the field observing lizards, including 10 months studying the ecology and social dynamics of the Jamaican lizard Anolis lineatopus. This study reported detailed observations of many aspects of behavior, including detailed descriptions of the signaling displays used during intraand interspecific interactions (A. S. Rand, 1967, “Ecology and Social Organization in the Iguanid Liz-

Morphology and ecology of the Mexican cave anole Anolis alvarezdeltoroi

Abstract: NSF grant DEB 0844624 to Steven Poe as well as DGAPA, UNAM (PAPIIT no. 224009) and CONACYT (no. 154093), both to Adrian Nieto Montes de Oca.