Comparative larval morphology of eight species of Hypsiboas Wagler (Amphibia, Anura, Hylidae) from Argentina and Uruguay, with a review of the larvae of this genus

Abstract

We studied the external and oral cavity morphology of the tadpoles of eight species of Hypsiboas in the H. albopunctatus, H. faber, H. punctatus and H. pulchellus species groups. After a review of the available information about larval external and oral cavity morphology, no character state seems to be synapomorphic for Hypsiboas. The presence of a fleshy projection in the inner margin of the nostrils and rounded vacuities of the anteromedial surface of the choanae (pending the confirmation of the latter in Hyloscirtus and Myersiohyla) seems to be synapomorphic for the tribe Cophomantini, as previously noticed by other authors. Some putative synapomorphies are suggested for some species groups of Hypsiboas, but a denser sampling is needed to study the taxonomic distribution of these character states, in order to determine which clades they may support. The presence of lateral flaps with labial teeth in the oral disc is a variable feature of many species in the H. faber and H. pulchellus groups. A spiracular tube free from the body wall is present in some species, mostly in the H. albopunctatus group, but also in the H. rufitelus, H. faber and H. pulchellus groups. Unique ventrolateral cumules of neuromasts are present in H. faber, and also in some species of other groups of Hypsiboas and of the sister genus Aplastodiscus. Our results highlight the importance of studying the taxonomic distribution of many character states that were sometimes overlooked in tadpole descriptions but seem relevant to test phylogenetic hypothesis.

Larval Development and Synapomorphies for Species Groups of Hyloscirtus Peters, 1882 (Anura: Hylidae: Cophomantini)

“…In early stages, the spots are located on the neuromast lines, but as the tadpole grows, the spots gradually move apart from the line pattern and increase in size. Kolenc et al (2008) described spots in species of various groups of Hypsiboas and Aplastodiscus and confirmed by SEM study that these are cumuli of neuromasts. The spots reported by Kolenc et al (2008) are similar to the ones observed in Hyloscirtus and probably correspond to the same structure.…”

“…Marinelli et al (1985) and Marinelli and Vagnetti (1988) offer detailed descriptions of development of larval oral features, and detected that in the studied taxa the distal tooth rows hold small, newly formed teeth while the proximal rows are older, formed by thick replacement teeth that push out the smaller ones worn by use. Teeth on the distal rows in the oral disc of Hyloscirtus are smaller than the teeth on the proximal rows (Duellman and Altig, 1978;Ruiz-C. and Lynch, 1982;La Marca, 1985;Cadle and Altig, 1991;Mijares-Urrutia, 1992;Lötters et al, 2005;Kolenc et al, 2008;pers. obs.…”

“…oral disc beside the jaw sheaths. The term ''flaps'' is used by Duellman et al (1997) to denote these structures (used again by Kolenc et al, 2008). Altig and McDiarmid (1999) recognize two types of accessory tooth rows parallel to the lateral end and nearly at right angles to the posterior tooth rows.…”

“…Number of submarginal papillae grows as the tadpole develops. Submarginal papillae begin to form teeth and fuse with the submarginal papillae beside them to form the accessory tooth rows or flaps (as used by Duellman et al, 1997 andKolenc et al, 2008), which are larger and more abundant in late stages (Fig. 4D, top to bottom).…”

Calls and tadpoles of the species of Lysapsus (Anura, Hylidae, Pseudae)

“…Several other similar examples abound in the literature (Pombal-Jr. and Haddad, 1999;Abrunhosa et al, 2005;Canedo and Pombal-Jr., 2007;Glaw et al, 2010). Likewise, tadpole morphology has been crucial to recognize genera (Cruz, 1982) and diagnose species of several Neotropical anuran groups (Kolenc et al, 2008;Weber and Caramaschi, 2008). Despite the obvious importance of such characters, advertisement calls and larvae morphology of most Brazilian anuran species are unknown (Bastos et al, 2011;Provete et al, 2011), and such data paucity limits comprehensive comparisons needed to resolve problems with amphibian anuran taxonomy.…”