HOMONOTA HORRIDA (South American Marked Gecko). AQUATIC LOCOMOTION.

VALDEZ OVALLEZ, FRANCO MIGUEL; GÓMEZ ALÉS RODRIGO; ACOSTA JUAN CARLOS; CORRALES LUCAS; FERNANDEZ RUBEN; ACOSTA RODRIGO; MARTINEZ TOMÁS AGUSTÍN; BLANCO GRACIELA

HERPETOLOGICAL REVIEW

Salt-Lake City

Año: 2019

0018-084X

Homonota horrida has crepuscular and nocturnal habits, is insectivorous, and is common in rocky mountains and cracks of urban constructions. It occurs in thephytogeographic provinces of Monte and Chaco up to 2500 m elev. (Cei 1993. Museo Regionale di Scienze Naturali, Monogr. 14, Torino, Piedmont). On 26 November 2017 at 2134 h, in at La Majadita, Valle Fértil, San Juan, Argentina (30.7152°S, 67.4940°W; WGS 84; 1006 m elev.), an adult H. horrida was observed floating onwater in a slow-flowing stream (Fig. 1),while hunting hemipterans (Gerridae). The lizard was suspended on the surface of the water and swam in it, making snake-like motions, to try to capture approaching insects. Locomotion at the air-water interface evolved in more than a thousand species, including insects, fish, reptiles, and mammals (Bush and Hu 2006. Annu. Rev. Fluid Mech. 38:339?369) and surface tension forces play an important role in surface locomotion over water (Nirody et al. 2018. Curr. Biol. 28:4046?4051). In contrast to our observation, Nirody et al. (2018) described the aquatic locomotion of Hemidactylus platyurus, which is limited to running quadrupedally with the hind end of the body falling just under the water surface due to its inabilityto adopt an erect posture as in basilisks. It is unlikely that this behavior in water by H. horrida would affect the adhesive system, and thus subsequent terrestrial locomotions (Stark et al. 2014. PLoS ONE 9:e101885; Stark et al. 2012. J. Exp. Biol. 215:3080?3086). It could also imply possible advantages in the trophic ecology of the species (Nieva et al. 2016. Iheringia, Sér. Zool. 106) when exploiting new food resources and, at the same time, decreasing intraspecific competition.