Chondrocranial morphology ofLeptodactylus larvae (Leptodactylidae: Leptodactylinae): Its utility in phylogenetic reconstruction

Abstract

Chondrocranial morphology of leptodactylid frogs is scarcely known and has not been completely described for any species of Leptodactylus. We describe the diversity of chondrocranial morphology in the genus Leptodactylus based on the analysis of 22 species, representing the four species groups: the fuscus Group, ocellatus Group, melanonotus Group, and pentadactylus Group. Furthermore, 26 characters are identified and used in a phylogenetic analysis. The phylogenetic analysis using Physalaemus, Crossodactylus, and Hylodes as outgroups suggests two monophyletic clades within Leptodactylus: the melanonotus-ocellatus clade and the pentadactylusfuscus clade. However, it does not support the monophyly of the species groups as currently recognized and it suggests a paraphyletic Leptodactylus. Enforcing the monophyly of the ingroup, i.e., Leptodactylus, results in the same major two clades of Leptodactylus. Leptodactylus riveroi, a taxon previously unassigned to any species group, appears most closely related to the melanonotus-ocellatus clade based on chondrocranial characteristics.

Phylogeny of frogs as inferred from primarily larval characters (Amphibia:Anura)★

“…Posterolateral projections of the crista parotica absent (0); process present (1); expansive flat chondrifications (2); processus otobranchialis (3). The posterolateral part of the crista parotica may bear a pointed or rounded processus posterolateralis (for example, Larson and de S a a, 1998). In some of the pipoids, microhylids, and species of Pseudis, the crista parotica was expanded into a flat horizontal plate of cartilage (Fig.…”

“…Sokol (1981) discussed the possible phylogenetic significance of the levels of attachment of the processus ascendens, concluding ''the more derived the taxon is, the lower is its ascending process'' (Sokol, 1981, p. 176). He defined ''high,'' ''intermediate,'' and ''low'' levels of attachment of the processus ascendens with reference to the position of the foramen oculomotorium (as applied in Larson and de S a a, 1998;Maglia et al, 2001). The foramen is located immediately dorsal to the trabecula cranii.…”

“…Furthermore, there is an amazing variety of larval forms displaying a broad spectrum of sizes, body shapes, feeding types, developmental rates, and habitat preferences (Orton, 1953;Altig and Johnston, 1989;McDiarmid and Altig, 1999). Comparative morphological studies have shown that there is substantial morphological diversity among larvae that has not yet been fully analyzed and synthesized (e.g., Pusey, 1943;Sokol, 1977aSokol, , 1981Wassersug, 1980Wassersug, , 1989Wassersug and Rosenberg, 1979;Lavilla, 1992, 1993;Haas, 1996Haas, , 1997Haas, , 2001Haas and Richards, 1998;Larson and de S a a, 1998;Cannatella, 1999;Maglia et al, 2001). Some larval features, particularly external features such as the mouthparts and the position of the spiracle opening, have been an integral part of frog systematics for more than 50 years (Noble, 1925;Orton, 1953;Inger, 1967;Ford and Cannatella, 1993).…”

“…But for a long time, the use of larval characters in phylogenetic studies has hardly advanced beyond the use of OrtonÕs general tadpole types (Orton, 1953), despite the accumulating morphological evidence. Among others, Pusey (1943) and Sokol (1981) have discussed the potential phylogenetic significance of larval internal anatomical features, but the first cladistic analyses of selected larval characters and taxa were published only since the 1990s (Haas, 1996(Haas, , 1997Larson and de S a a, 1998). Recently Maglia et al (2001) presented a combined analysis of larval and adult characters.…”

Systematics, distribution, and bibliography of the frogLeptodactylus validusGarman, 1888 (Amphibia: Leptodactylidae)

“…A lateral view and oral disk of the tadpole are pictured inKenny (1969a) (as L. podicipinus petersi [sic]), and illustrations of the dorsal, ventral, and lateral aspects of the chondocranium, as well as a ventral view of the hyobranchial apparatus, are inLarson & de Sa´(1998).Canonical variance scatterplots of tadpole chondrocrania and hyobranchial skeletons including L. validus are in Vera Candioti et al (2007). Nokhbatolfoghahai & Downie (2005) created schematics and/or SEMs of larval cement gland development, distribution pattern of hatching gland cells (2007), development and morphology of hatching gland cells (2007), general organization of external gills (2008), and external gill development (2008).…”