Batrachylodes

Brown, Rafe M., Siler, Cameron D., Richards, Stephen J., Diesmos, Arvin C. & Cannatella, David C., 2015, Multilocus phylogeny and a new classification for Southeast Asian and Melanesian forest frogs (family Ceratobatrachidae), Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 174 (1), pp. 130-168 : 152

SUBGENUS BATRACHYLODES BOULENGER, 1887

Type species

Batrachylodes vertebralis Boulenger, 1887 .

Diagnosis

Species of the subgenus Batrachylodes form a phenotypically and ecologically cohesive group, differing from other members of the genus Cornufer by having (1) a small body size (males 17–24 mm SVL; vs. ≥ 25 mm); (2) stout, triangular bodies (vs. body shape slender, not triangular); (3) pointed snouts (vs. rounded); and (4) slightly expanded to widely expanded terminal discs of fingers and toes (vs. terminal discs non-expanded); and by the (5) presence of darkened loreal stripes continuing diagonally across the flank to form a distinctly stratified lateral body marking (i.e. clearly demarcated darker dorsal and lighter ventral colours) in most species (vs. absence); and (6) absence of interdigital webbing (vs. presence in Potamorana and Discodeles ). We consider body shape (microhylid-like; generally triangular bodies with very small heads and strongly pointed snouts) and stratified coloration (light above, dark on lateral surfaces) to be synapomorphies for the subgenus ( Boulenger, 1887; Sternfeld, 1920; Brown & Parker, 1970), which is strongly supported in our phylogeny ( Fig. 2, Clade L).

Phylogenetic definition

Batrachylodes is an apomorphy-based name for the clade ( Fig. 2, Clade L) originating in the ancestor of Cornufer (Batrachylodes) vertebralis and Cornufer (Batrachylodes) trossulus , in which the following apomorphy, synapomorphic with that in Batrachylodes vertebralis , originated: very small, triangular bodies with small heads and strongly pointed snouts ( Fig. 2).

Content

Seven species formerly referred to the genus Batrachylodes (i.e. excluding Cornufer minutus ; Fig. 2, and below), exclusively from the Solomon Islands ( Brown & Parker, 1970: Cornufer elegans , Co. gigas, Co. mediodiscus, Co. montanus, Co. trossulus, Co. vertebralis , and Co. wolfi ; Table 3). Brown et al. (2013) discussed an undescribed species from New Britain Island, Bismarck Archipelago (the first report of a species of this genus outside the Solomon Island Archipelago; Foufopoulos & Richards, 2007).

Comment

The species not sampled by us ( B. elegans , B. gigas , B. mediodiscus , and B. montanus ) from the morphologically cohesive and biogeographically circumscribed Batrachylodes are also placed in Batrachylodes because they share the synapomorphy on which the phylogenetic name is based. We exclude Co. minutus from this group on the basis of its unstable phylogenetic affinities ( Fig. 2), which, in the combined data set suggest a closer relationship to Melanesian ( Cornufer sp. Halmahera, Cornufer batantae , and Cornufer bimaculatus ) species than to members of the subgenus Batrachylodes , with the caveat that support for this relationship is low ( Fig. 2).

Etymology

Although Boulenger (1887) provided no etymology for Batrachylodes , the name is most likely derived from the Greek ‘batrachus’, meaning frog, and possibly ‘hylodes’, in reference to the genus Hylodes . Boulenger’s (1882) concept of Hylodes included 45 species that are today allocated to Pristimantis , Eleutherodactylus , Lithodytes , Batrachyla , and other genera. One of Boulenger’s diagnostic characters for Hylodes was expanded digital discs, such as are present in some Batrachylodes species. Hylodes is almost certainly derived from Hyla - + ‘-odes’ (Greek), meaning like or similar to Hyla , implicitly with expanded discs. Common name: Solomon Islands sticky-toed frogs.