Afrotyphlops congestus ( Duméril & Bibron, 1844 )

Sánchez-Vialas, Alberto, Calvo-Revuelta, Marta & Riva, Ignacio De La, 2022, Synopsis of the terrestrial Reptiles of Equatorial Guinea, Zootaxa 5202 (1), pp. 1-197 : 123-124

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 ) .

Figures

FIGURE 31. From left to right: lateral, dorsal and ventral views of the head of: Afrotyphlops congestus “blotched phenotype” (A) (MNCN 23354), Afrotyphlops congestus “striped phenotype” (B) (EBD 31531), and Letheobia caeca (C) (in the EBD collection, without EBD number). Photos: AS-V.

MAPS 36 A–C. Distribution maps for Equatorial Guinean records of (A) Afrotyphlops congestus; (B) Indotyphlops braminus; (C) Letheobia caeca (question mark represents an imprecise record).