Pseudohemisus verrucosus Angel, 1930

Scherz, Mark D., Schmidt, Luca, Crottini, Angelica, Miralles, Aurélien, Rakotoarison, Andolalao, Raselimanana, Achille P., Köhler, Jörn, Glaw, Frank & Vences, Miguel, 2021, Into the Chamber of Horrors: A proposal for the resolution of nomenclatural chaos in the Scaphiophryne calcarata complex (Anura: Microhylidae), with a new species-level phylogenetic hypothesis for Scaphiophryninae, Zootaxa 4938 (1), pp. 392-420 : 410

Pseudohemisus verrucosus Angel, 1930

Name-bearing type: Lectotype by present designation, MNHN 1929.233 , from “Lavenombato, bords de l’Onilahy” according to the original description.

The original syntype series contained five syntypes; MNHN 1929.231 – 232 and 234–235 are to be considered as paralectotypes.

This nomen has been considered a dubious species by Blommers-Schl̂sser & Blanc (1991) and is considered to be a nomen inquirendum in Frost (2020). The original type series of five syntypes was collected at a locality in south-western Madagascar, where S. brevis is common and where the S. calcarata complex has only recently been documented ( D’Cruze et al. 2009).

Four of the specimens (MNHN 1929.231–234) are juveniles, in a satisfactory state of preservation, and clearly belong to Scaphiophryne based on the presence of an enlarged inner metatarsal tubercle and presence of a tarsal tubercle. The fifth number (MNHN 1929.235) refers to a series of five tadpoles, which probably do not belong to Scaphiophryne . Because the types of verrucosus are not adults, it is difficult to ascertain their identity. We here designate the specimen MNHN 1929.233 (with the most strongly expressed tubercular state of the dorsum) as lectotype of Pseudohemisus verrucosus Angel, 1930 in an effort to stabilize this nomen given the heterogeneity of the type series.

Morphology. The most distinctive character of MNHN 1929.231 – 234 is its strongly tubercular dorsum. The large tubercles are distinct, especially in the lectotype MNHN 1929.233 but less so in the paralectotype MNHN 1929.231 . However, in all four specimens these tubercles are recognizable, and they even form a pair of distinct, parallel dorsal ridges above the forelimb insertion. A dorsolateral ridge is also recognizable towards the front of the flank. The tips of the fingers and toes are not enlarged; the subarticular tubercle of the first toe does not appear to be distinctly enlarged or prominent ( Fig. 9 ) .

Osteologically, the lectotype appears to be a juvenile, because several components of its skeleton are not fully ossified. However, it does have all the hallmarks of Pseudohemisus identified in the other specimens examined here, although the type of vertebral articulation is not ascertainable due to the damage to the specimen ( Fig. 10 , Supplementary Figs S2–S 3 ).

Assignment. As far as known, distinct dorsal tubercles and ridges are not known from Scaphiophryne calcarata sensu lato, whereas specimens of S. brevis , especially in life, can have a tubercular dorsum (see photos in Glaw & Vences 2007). In addition, a photograph taken by N’ D’Cruze at Sept Lacs, not far from the Onilahy/ Toliara region (reproduced in Glaw & Vences 2007: page 448) shows a specimen assigned to S. brevis with several of the characters of the verrucosus types, i.e., rather distinct dorsolateral ridge in the anterior part of body, and dorsum with tubercles forming short dorsal ridges. D’Cruze et al. (2009) collected voucher specimens of S. brevis and S. “ calcarata ”. Examining these specimens and carrying out additional collections in the region will be necessary to understand the variability of juvenile S. brevis and to understand whether an additional, previously unrecognized species of Scaphiophryne with tubercular dorsum may occur in this region to which the nomen verrucosus may be assignable.

Considering the general variability observed within Scaphiophryne species in characters regarding shape of subarticular tubercles and dorsal skin texture (e.g., tubercular vs. smooth in specimens of S. madagascariensis from different localities), we propose to consider the nomen Pseudohemisus verrucosus Angel, 1930 as a junior synonym of Scaphiophryne brevis , which appears to be the most plausible hypothesis in light of the current state of knowledge.

Figures

FIGURE 2. Haplotype networks based on DNA sequences of two nuclear genes, POMC (310 bp) and RAG-1 (788 bp) for species of Scaphiophryne and Paradoxophyla. Small black circles represent additional mutational steps between identified haplotypes. Colors of taxa correspond to those in Fig. 1.

FIGURE 3. Individuals in life of the three species of Scaphiophryne in the subgenus Pseudohemisus according to the classification proposed in the present paper: Scaphiophryne brevis from Ifaty (A–E), Kirindy (F–G) and Isalo (H); S. calcarata from Pic St. Louis near Tolagnaro (I–K), Ambalavao (L), Isalo (Ilakaka) (M–N), Sakaviro (O) and near Anja (P); S. obscura from Isalo (Q), Kirindy (R–V), Ankarafantsika (W), and Bongolava Plateau (X). Photos by F. Glaw, J. Lobon-Rovira, A. Miralles, G. M. Rosa, and M. Vences.

FIGURE 9. Photographs of the details of morphology of type specimens of the nomina in the genus Scaphiophryne (subgenus Pseudohemisus) except the holotype of S. brevis, showing feet (left column) and hands (middle column) in ventral view, and the head (right column) in lateral view.

FIGURE 10. Micro-CT scans of the name-bearing type specimens of nomina in the subgenus Scaphiophryne (Pseudohemisus) except the holotype of S. brevis: skulls in dorsal, ventral and lateral views.