Sexual dimorphism in Leptodactylus latinasus (Anura, Leptodactylidae): nasal capsule anatomy, morphometric characters and performance associated with burrowing behavior

Abstract

Ponssa, M.L. and Barrionuevo, J.S. 2012. Sexual dimorphism in Leptodactylus latinasus (Anura, Leptodactylidae): nasal capsule anatomy, morphometric characters and performance associated with burrowing behavior. -Acta Zoologica (Stockholm) 93: 57-67.In anurans, the ability to burrow has been associated with the characteristics of external morphology, with modifications in the musculoskeletal system and even in some brain regions. Male Leptodactylus fuscus construct subterranean chambers with the snout, where the eggs are deposited and early larval stages develop. Leptodactylus latinasus, a member of the L. fuscus group, is a good model to test the relationship among digging behavior of males, sexual divergence in the morphology of the nasal region, cranial-dimensions, and performance as digger. The goal of this work is to provide a detailed morphological description of the olfactory region, which allows detecting sexually dimorphic characters, to evaluate sexual divergence with head dimension data, and to test whether differences exist in the digging performance of each sex. Our data do not clearly indicate sexual dimorphism in head size, nasal region morphology or digging performance that can be linked with the burrowing behavior. Thus, the only unequivocal sexually dimorphic character associated with the construction of the nuptial chamber by males would be the rigid, chisel-like snout, present exclusively in males.

Phylogenetic patterns and correlation of key structures for jumping: bone crests and cross‐sectional areas of muscles inLeptodactylus(Anura, Leptodactylidae)

“…) and, in this case, the only associated morphological modifications are the development of a rigid chisel‐like snout and the ossification of the nasal cartilage region (Heyer, ; Ponssa, ; Ponssa et al. ; Ponssa & Barrionuevo, ; Ponssa & Medina, ). Other more typical burrower anurans demonstrate muscle features particular to more persistent digging behavior: Hemisus, for example, shows powerful muscles used for head‐first burrowing that involves flexing the head and retracting the front legs (Emerson, ; Wells, ); hindlimb burrowers (e.g.…”

“…The assigning of subcategories was based on observations documented in the literature (Heyer, ; Ponssa & Heyer, ; Ponssa, ; Ponssa et al. ; Ponssa & Barrionuevo, ; de Sá et al. ) , personal observations on field expeditions and morphological evidence conspicuously associated with swimming (presence of toe fringes: Heyer, ; Goldberg & Fabrezi, ; de Sá et al.…”

“…For the species not included in that previous work, we followed the same criteria as Fratani et al (2017) to assign the locomotor mode. The assigning of subcategories was based on observations documented in the literature (Heyer, 1978;Ponssa & Heyer, 2007;Ponssa, 2008;Ponssa et al 2011;Ponssa & Barrionuevo, 2012;de S a et al 2014) , personal observations on field expeditions and morphological evidence conspicuously associated with swimming (presence of toe fringes: Heyer, 1969;Goldberg & Fabrezi, 2008;de S a et al 2014), jumper or hopper (pelvic type: Reilly & Jorgensen, 2011;Jorgensen & Reilly, 2013). Although burrowing has generally been considered a locomotor mode (Emerson, 1978(Emerson, , 1979(Emerson, , 1988Jorgensen & Reilly, 2013), some authors regard it as an activity pattern related to substrate use (Lires et al 2016).…”

“…The burrower species dig depressions or build underground incubation chambers for the foam nest where the eggs are deposited (Heyer, 1978). In Leptodactylus and Adenomera, this behavior exclusively involves the use of the hindlimbs and/or head (Philibosian et al 1974;Pisan o et al 1993;Prado et al 2002;Marahão Dos Santos & Oliveira Amorim, 2005;Silva et al 2005) and, in this case, the only associated morphological modifications are the development of a rigid chisel-like snout and the ossification of the nasal cartilage region (Heyer, 1978;Ponssa, 2008;Ponssa et al 2011;Ponssa & Barrionuevo, 2012;Ponssa & Medina, 2016). Other more typical burrower anurans demonstrate muscle features particular to more persistent digging behavior: Hemisus, for example, shows powerful muscles used for head-first burrowing that involves flexing the head and retracting the front legs (Emerson, 1976;Wells, 2008); hindlimb burrowers (e.g.…”

Intrasexually selected weapons

“…In this review, we follow the traditional division of sexually dimorphic traits in three groups: primary, secondary, and ecological sex traits (Darwin, 1871;Andersson, 1994;Williams & Carroll, 2009); yet we highlight the necessity of an in-depth discussion of this classification taking into account fecundity selection (review in Pincheira-Donoso & Hunt, 2017), social competition (West-Eberhard, 1983), and sexual differences in offspring care or other behaviours associated with reproduction (e.g. Cade & Maclean, 1967;Wilson et al, 2003;Ponssa & Barrionuevo, 2012). Primary sex traits are necessary for sexual reproduction and thus naturally selected (Andersson, 1994), although aspects of them can also be sexually selected (review in Simmons, Lüpold & Fitzpatrick, 2017).…”