Atheris squamigera (Hallowell, 1855)

Ceríaco, Luis M. P., Marques, Mariana P. & Bauer, Aaron M., 2020, The Bush Vipers, genus Atheris Cope, 1862 (Squamata: Viperidae) of Bioko Island Gulf of Guinea, with the description of a new species, Zootaxa 4838 (4), pp. 581-593 : 584-585

Atheris squamigera (Hallowell, 1855)

Echis squamigera Hallowell, 1855: 193

Atheris squamiger: Boulenger (1905: 216)

Atheris squamigera squamigera [part]: Capocaccia (1961: 304)

Atheris squamiger squamiger: Mertens (1964: 235)

Atheris squamigera: Wallach et al. (2014: 64) ; Chippaux & Jackson (2019: 78)

Boulenger (1905) was the first to denote the presence of the species in the island, as Atheris squamiger [sic], based on an unnumbered series of specimens collected by the Italian explorer Leonardo Fea (1852–1903) in Moka, southern Bioko Island. These specimens were later studied in more detail by Capocaccia (1961), who reported one female and one juvenile of the species. For the female (MSNG/CE 30428a), the author provided a detailed description, which has 150 ventral scales, 52 subcaudals, 25 scales rows around the neck, 21 at midbody, and 15 before the cloaca, 10 supralabials and 10 infralabials, three scales between the nasals and eye on the right side of the head, two on the left, nine interoculars, 14 oculars on the right side, 17 on the left side, and only one row of scales between eye and supralabials. For the juvenile (MSNG/CE 30428b), Capocaccia (1961) reported 150 ventrals, 53 subcaudals, 25 scales rows around the neck, 20 at midbody, and 17 before the cloaca, nine supralabials on the right, but 10 on the left side, 10 infralabials on the right side, nine on the left side, two scales between nasal and the eye, nine interoculars, 15 oculars on the right side, 14 on the left side, and only one row of scales between the eye and supralabials. Both these specimens were reviewed by us (this study).

Mertens (1964) reported a total of seven poorly preserved specimens (see Bibliographic Records below), three males, three females and a juvenile female. All the characters presented by Mertens (1964) unambiguously identify these specimens as the same taxon as those cited by Capocaccia (1961) and the material present in the CAS collections. According to Mertens (1964), three specimens had seven interoculars, three others had eight, and a single individual had nine; all the specimens had only single row of scales between the eyes and supralabials. In males there were 19–24 midbody scale rows, 148–153 ventrals and 57–60 subcaudals in males, 148–155 ventrals and 46–51 subcaudals in females, and 145 ventrals and 56 subcaudals in the juvenile female. According to Mertens (1964) these specimens did not have dark streaks behind the eye.

The recent material comprises two adult males (CAS 201867, CAS 201869) and two adult females (CAS 201866, CAS 201868 [ Fig. 1 ]). The measurements, meristic and scalation data ( Table 1) of all of these specimens agree entirely with A. squamigera , and all specimens have a small dark band extending posteriorly from the eye. This dark band is, however, not as large and conspicuous as that of Atheris broadleyi , and is similar to the small bands typical of other A. squamigera from the continent, including the type specimen of the species, still present in the collections of the Academy of Natural Sciences of Drexel University (ANSP 6949), in Philadelphia, USA (see Lawson 1999). In terms of coloration, all specimens have an olive-green background, with a series of transverse black and yellow bars from the neck region to the tail base. The tip of the tail is black. Ventrally, all specimens are yellowish green, with some ventrolateral yellow spots at the outer limits of the ventrals. The species is currently only known from the central and southern regions of the island, near Moka ( Fig. 2 )

Material examined. Bioko Island, Equatorial Guinea: CAS 207866–207868 , vic. Moka Malabo (3.52267º, 8.69417º, 1168 m), collected by Robert C. Drewes, Lindsay G. Henwood and Jens V. Vindum on 2 and 3 of October 1998 ; CAS 207869 , small creek on E side of Moka (3.36672º, 8.66492º, 1553 m), collected by Robert C. Drewes, Lindsay G. Henwood and Jens V. Vindum on 3 of October 1998 ; MSNG 30428 b,c, Moka (3.35081º, 8.66254º, 1369 m), collected by Leonardo Fea on 1901–1902 .

Bibliographic records (not examined). Seven specimens (still in the collections of the Zoologisches Forschungsinstitut und Museum Alexander Koenig, under the accession numbers ZFMK / REP 5452–5456 ), three male adults, three female adults and one juvenile from “Moca” [=Moka] (3.35081º, 8.66254º, 1369 m), collected by Martin Eisentraut between 7 of November 1962 and 19 of February 1963 ( Mertens 1964) .

Figures

FIGURE 1. Specimen of Atheris squamigera (CAS 207868) from Bioko Island.

FIGURE 2. Distribution map of the Atheris on Bioko Island. Orange circles: Atheris squamigera; Blue stars: Atheris hetfieldi sp. nov.