Afrotyphlops congestus (Duméril & Bibron, 1844)

Figure 31A–B

Onychocephalus congestus Duméril & Bibron, 1844: 334 . Type locality: unknown.

Onychophis barrowii Gray, 1845: 133 . Type locality: “ India?” (in error fide Hahn 1980: 68).

Typhlops crassatus Peters, 1881c: 50 . Type locality: “Chinchoxo, durch die africanische Gesellschaft” (= Cabinda, Angola).

Rhinotyphlops congestus (Duméril & Bibron, 1844): Broadley & Wallach 2000: 167.

Afrotyphlops congestus (Duméril & Bibron, 1844): Broadley & Wallach 2009: 46.

Distribution. It extends from southeastern Nigeria to the West of Uganda, southward to the Republic of the Congo. In Equatorial Guinea it has been recorded in Bioko at Basilé (Bocage 1895a; Bocage 1903; Roux-Estève 1974) and Moka (Mertens 1964a), and in Río Muni at Monte Alén National Park (Lasso et al. 2002) (Map 36A).

Comments. Afrotyphlops congestus was formerly considered by some authors as a subspecies of A. punctatus (Leach, 1819) (Werner 1913; Roux-Estève 1974; see Broadley & Wallach 2009). Some molecular works that included samples of both taxa, supported their independent species status (Vidal et al. 2010; Hedges et al. 2014; Pyron & Wallach 2014; Nagy et al. 2015). In Wallach et al ’s. (2014) catalogue, A. punctatus is included in the fauna of Bioko, maybe as a result of a mistake coming from the previous status of A. congestus as a subspecies of A. punctatus . Taking into account (1) the high morphological similarity shown by A. punctatus and A. congestus, and (2) the ecology of these two species, in which A. punctatus usually occurs in savannah environments (Trape & Baldé 2014) whereas A. congestus exclusively inhabits forests, we follow Roux-Estève (1974) in considering all the populations from Equatorial Guinea (both Bioko and Río Muni) as A. congestus, excluding A. punctatus from the reptile list of the country. Afrotyphlops congestus, like some other related species [e.g. A. punctatus, A. liberiensis (Hallowell, 1848)], presents two phenotypes, a “marbled” form and a “striped” form, the first one being more common in A. congestus (Roux-Estève 1974) . Mertens (1964) reported the striped phenotype of A. congestus in Moka, Bioko. We found both phenotypes among the examined specimens either from Río Muni or Bioko: MNCN23354, MNCN23355, MNCN23357, EBD 20801, 27520, 24963 depict a marbled pattern, whereas MNCN23356 and EBD 2843 show a striped pattern. The pholidosis traits of the examined specimens fall within the variability of the species [midbody scale rows: 28 (MNCN23356), 31 (MNCN23357), and 30 (MNCN23354, MNCN23355); number of dorsal longitudinal scales: 332 (MNCN23356), 333 (MNCN23357), 383 (MNCN23355), 394 (MNCN23354)]. The examined specimens from Río Muni present a greater number of dorsal longitudinal scales (383–394) than the Biokoan examined specimens (332–333).

There is a taxonomic question dealing with the striped phenotype, pending resolution until more data are available. Some putative undescribed species of Afrotyphlops are shown by Chirio & LeBreton (2007). For example, the one named “ Rhinotyphlops sp.3 ”, is morphologically similar to some striped specimens of A. congestus . These authors noted the same pholidotic pattern in their undescribed form “ Rhinotyphlops sp.3 ” and in A. congestus . A molecular phylogeography including both the “marbled” and “striped” phenotypes of A. congestus, together with samples of specimens assignable to the putative new taxa depicted by Chirio & LeBreton (2007) will be required in order to resolve this taxonomic conundrum. With the data at hand, we tentatively consider all the examined striped specimens as A. congestus .

Specimens examined. Eight specimens. Río Muni: without specific locality, 1885 (MNCN 23354–23355) . Nvom (road from Aconibe to Asoc), 08April 1987 (EBD 24963) . Miboman (road from Movo to Niefang), September 1987 (EBD 27520) . Miboman (Km 27, road from Bata to Movo), 02 June 1986 (EBD 20801) . Enuc, 12 April 1965 (EBD 2843) . Bioko: without specific locality, 1876–1877 (MNCN 23356–23357) .