Tuesday, August 14, 2018

[Herpetology • 2018] Poyntonophrynus pachnodes • A New Earless Species of Poyntonophrynus (Anura, Bufonidae) from the Serra da Neve Inselberg, Namibe Province, Angola

Poyntonophrynus pachnodes
Ceríaco, Marques, Bandeira, Agarwal, Stanley, Bauer, Heinicke & Blackburn, 2018

“Serra da Neve Pygmy Toad - Sapo Pigmeu da Serra da Neve”  DOI:  10.3897/zookeys.780.25859
Photos by Ishan Agarwal and Luis Ceríaco. 

African pygmy toads of the genus Poyntonophrynus are some of the least known species of African toads. The genus comprises ten recognized species endemic to sub-Saharan Africa, five of which are restricted to southwestern Africa. Recent field research in Angola provided new material for three species of Poyntonophrynus, including a morphologically distinctive population from the Serra da Neve Inselberg. Based on a combination of external morphology, high-resolution computed tomography scanning, and molecular phylogenetic analysis, the Serra da Neve population is described as new species that is nested within the genus. The most striking character that differentiates the newly described species from its congeners is the lack of a tympanic middle ear, a condition common in the family Bufonidae, but so far not known for Poyntonophrynus. The description of this new species from southwestern Angola reinforces the biogeographic importance of the region and further suggests that southwestern Africa is the cradle of diversity for this genus.

Keywords: Africa, Amphibia, columella, osteology, toad

Figure 6. Photograph in life of Poyntonophrynus pachnodes sp. n., paratype UF 184183 (AMB 10191). Photo by Ishan Agarwal.

Poyntonophrynus pachnodes sp. n.

Diagnosis: Poyntonophrynus pachnodes sp. n. is a small-bodied bufonid that lacks tarsal folds, a character that distinguishes it from bufonids in Angola except Mertensophryne and Poyntonophrynus. It differs from all Mertensophryne in having inconspicuous parotoid glands, compared to pronounced parotoid glands that form a shelf in the scapular region of Mertensophryne, and in lacking reduction of the phalanges (Grandison, 1981). The newly described species differs from all other members of the genus Poyntonophrynus in lacking a tympanum and columella.

Figure 7. High-resolution Computed Tomography reconstructions showing the skeleton of the holotype (UF 184184) of Poyntonophrynus pachnodes sp. n. in dorsal view (A), skull in dorsal (B), right lateral (C) and ventral (D) views, pelvis in right lateral view (E), pectoral girdle in ventral view (F), and right foot (G) and right hand (H) in ventral views. Selected skeletal elements are labeled based on discussion in the text. Panel A also highlights the eggs that are visible within the oviducts. 
Abbreviations: m – maxilla; np – neopalatine; pt – pterygoid; q – quadrate; sph – sphenethmoid; sq – squamosal; v – vomer. Scale bars in each row equal 2 mm.

Figure 8. Southern view of the base of the Serra da Neve Inselberg (A), and habitat of the type locality at about 1500 m a.s.l. (B). Photos by Luis Ceríaco.

Distribution and ecology: The species is currently only known from the Serra da Neve Inselberg (Figs 2, 8) in northern Namibe Province. Specimens were found on moist soil under rocks and leaf-litter at dusk in a semi-open miombo forest area. Grandvaux-Barbosa (1970) considered that Serra da Neve is characterized by a “sparse Miombo,” dominated by trees of the genera Julbernardia spp. and Brachystegia spp., and shrubs like Combretum spp. or Annona spp., which were observed at the site. The species was found sympatrically with the frogs Sclerophrys gutturalis and Tomopterna tuberculosa, the lizards Agama schacki, Trachylepis sulcata, Chondrodactylus pulitzerae, Hemidactylus benguellensis, Pachydactylus angolensis, and Heliobolus lugubris, and the snake Hemirhagerrhis viperina.

Etymology: The specific name pachnodes (Gr.) means “frosty” and is used as an adjective (Brown 1954). This is a reference to both the cool climate at the higher elevation where this species occurs (1488 m) and that Serra da Neve (Port.) translates to “mountain of snow.” 
We suggest “Serra da Neve Pygmy Toad” and “Sapo Pigmeu da Serra da Neve” as the English and Portuguese common names respectively.

 Luis M. P. Ceríaco, Mariana P. Marques, Suzana Bandeira, Ishan Agarwal, Edward L. Stanley, Aaron M. Bauer, Mathew P. Heinicke and David C. Blackburn. 2018. A New Earless Species of Poyntonophrynus (Anura, Bufonidae) from the Serra da Neve Inselberg, Namibe Province, Angola.  ZooKeys. 780: 109-136.  DOI:  10.3897/zookeys.780.25859