Cranial anatomy of tadpoles of five species of Scinax (Hylidae, Hylinae)

Abstract

We studied the oral apparatus, buccal cavity and musculoskeletal features in tadpoles of five species of the genus Scinax (S. acuminatus, S. uruguayus, S. aff. pinima, S. aromothyella, and S. berthae). Observed variation is mainly related to intrageneric grouping. Scinax acuminatus (S. ruber clade, sister taxon of S. rostratus group) has a distinctive combination of a mental gap in the margin of oral papillae, straight labial teeth with few or absent cusps, processus muscularis acute and posteriorly directed, and m. subarcualis rectus I with two slips. Scinax uruguayus and S. aff. pinima (S. uruguayus group) have keratinized sheets ventrolateral to the lower jaw sheath, well-developed infralabial and lateral ridge papillae, robust jaw cartilages, cornua trabeculae with short and widely divergent free portions, processus articularis short and wide, processus muscularis thin and directed anteriorly. Scinax aromothyella and S. berthae (S. catharinae group) have poorly developed, non-colored spurs behind the lower jaw sheath, long and thin processus articularis, wide and rounded processus muscularis, and tripartite cartilago suprarostralis. Anatomical features described are congruent with current phylogenetic arrangements based on molecular, chromosomal, and morphological data, and provide a source of information that can be useful to solve interspecific relationships within Scinax.

Comparative description and ossification patterns ofDendropsophus labialis(Peters, 1863) andScinax ruber(Laurenti, 1758) (Anura: Hylidae)

“…Previous studies of the cranial morphology in hylid tadpoles include Acris crepitans ( Maglia, Pugener & Mueller, 2007 ), Boana lanciformis ( De Sá, 1988 ; Alcalde & Rosset, 2003 ), Boana pulchella ( Hoyos et al, 2012 ), Boana raniceps and Dendropsophus nanus (former Hyla raniceps and Hyla nana Fabrezi & Lavilla, 1992 ; Vera Candioti & Haas, 2004 , Dryophytes versicolor (former Hyla versicolor, Sheil et al., 2014 ), Hyla orientalis ( Yildirim & Kaya, 2014 ), Julianus acuminatus (former Scinax acuminatus , Fabrezi & Lavilla, 1992 ; Faivovich, 2002 ; Alcalde & Rosset, 2003 ; Alcalde et al, 2011 ), J. uruguayus, J. aff. pinimus (former Scinax uruguayus and Scinax aff.…”

“…pinimus (former Scinax uruguayus and Scinax aff. pinima , Alcalde et al, 2011 ; Rodrigues et al, 2017 ), Ololygon aromothyella and O. berthae (former Scinax berthae , Rodrigues et al, 2017 ; Alcalde et al, 2011 ; Faivovich, 2002 ), O. skuki ( Rodrigues et al, 2017 ); Scinax granulatus and S. squalirostris ( Rodrigues et al, 2017 ; Alcalde & Rosset, 2003 ), S. boulengeri ( Rodrigues et al, 2017 ; Vera Candioti, 2007 ), S. fuscovariatus ( Fabrezi & Vera, 1997 ), S. nasicus ( Rodrigues et al, 2017 ; Vera Candioti, 2007 ; Vera Candioti, Lavilla & Echeverría, 2004 ; Fabrezi & Vera, 1997 ), S. ruber ( Haas, 1996 ). For a complete overview of the findings of these studies see Appendix 1 .…”

“…When comparing the development of D. labilis with D. nanus ( Vera Candioti, Lavilla & Echeverría, 2004 and Alcalde & Rosset, 2003 ), we found that D. labialis can be differentiated by the reduction of the buccopharyngeal and branchial basket structures and presence of processus quadrato etmoidale in ventral view. On the other hand, the information that is available for Scinax species ( Fabrezi & Lavilla, 1992 ; Haas, 1996 ; Fabrezi & Vera, 1997 ; Faivovich, 2002 ; Alcalde & Rosset, 2003 ; Vera Candioti, Lavilla & Echeverría, 2004 ; Vera Candioti, 2007 ; Alcalde et al, 2011 ; Rodrigues et al, 2017 ) reveal that there are a numerous variations that requires extending the morphological studies in tadpoles.…”

“…Comparative morphological descriptions for a specific group of frogs have provided useful systematic characters since 1960 (e.g., Cannatella, 1999 ; Duellman, Marion & Hedges, 2016 ). However, most studies of frog morphological characters focus on adults ( Faivovich, 2002 ; Faivovich et al., 2005 ; Maglia, Pugener & Mueller, 2007 ; Wiens et al, 2010 ; Pyron & Wiens, 2011 ; Yildirim & Kaya, 2014 ; Duellman, Marion & Hedges, 2016 ), and tadpoles have often been overlooked ( Alcalde et al, 2011 ). Of those comparative studies that examine tadpoles, most consider external morphological characters and skeletal characters are often neglected ( Fabrezi & Lavilla, 1992 ; Faivovich, 2002 ; Maglia, Pugener & Mueller, 2007 ; Hoyos et al, 2012 ; Yildirim & Kaya, 2014 ).…”

The remarkable larval anatomy of Proceratophrys minuta Napoli, Cruz, Abreu and Del‐Grande, 2011 (Amphibia: Anura: Odontophrynidae)

“…Absent or cartilago Meckelilower lip Absent Haas, 2001Haas, , 2003Ruibal & Thomas, 1988;Vera Candioti, 2005, 2007Ziermann, Infante, Hanken, & Olsson, 2013 Conrauidae --- Altig, 1991;Haas, 1995Haas, , 2001Haas, , 2003Krings, Klein, Heneka, & Rödder, 2017 Kolenc, Borteiro, & Baldo, 2011;Carr & Altig, 1991;Dias, Araújo-Vieira, Carvalho-e-Silva, & Orrico, 2019a;Vera Candioti, 2004, 2007Vera Candioti & Haas, 2004;Vera Candioti, Lavilla, & Echeverría, 2004;Vera Candioti, Haas, Altig, & Peixoto, 2017 Hylodidae Cartilago Meckeli-lower lip Absent Haas, 2003 Hyperoliidae Cartilago Meckeli-lower lip Absent Carr & Altig, 1991;Haas, 2003 Leiopelmatidae ---…”