Osteolaemus tetraspis Cope, 1861

Figure 6B

Osteolaemus tetraspis Cope, 1861a: 550 . Type locality: “Ogobai River, Western Africa”, Ogooué River, Gabon.

Crocodilus frontatus Murray, 1862: 213 . Type locality: “Old Calabar”, Duke Town, Nigeria.

Halcrosia afzelii Lilljeborg, 1867: 715 . Type locality: “ Sierra Leone, West Africa ”.

Halcrosia nigra Gray, 1867: 200 . Type locality: “ Senegal, Gabon; Old Calabar; Ogobai River ”.

Distribution. This species occurs from the Ogooué River Basin in Gabon to Nigeria and southwest of the Republic of the Congo. In Equatorial Guinea it has been recorded from Río Muni at Cabo San Juan (Boulenger 1905) and Monte Alén National Park (Lasso et al. 2002), including Monte Mitra Forest (Gonwouo & Nsang 2005) (Map 1B).

Comments. The taxonomy of the genus Osteolaemus was a complex matter before the molecular characterization of several populations across its distribution (Eaton et al. 2009). Molecular works support three distinct phylogenetic species within Osteolaemus, two of them being O. tetraspis and O. osborni Schmidt, 1919 from the Congo Basin, while the third remains as an undescribed taxon from West Africa (Eaton et al. 2009; Franke et al. 2013; Shirley et al. 2015). Osteolaemus tetraspis is a intensively harvested species in Río Muni, collected for the bush-meat market (a specimen from Monte Alén is shown in Figure 6B) (Fa & García Yuste 2001; Fa et al. 2002).

Specimens examined. Thirteen specimens. Río Muni: likely from Cabo San Juan as part of the material examined by Boulenger (1905) (MNCN 4171) ; without specific locality (MNCN 45315, EBD 21046); Ayamiken (EBD 34302) ; Asonga, 20 April 1986 (EBD 20912) ; Niefang, Cuenca del Uolo, 25 March 1987 (EBD 24934) ; Niefang Norte (EBD 20282) ; San Joaquín de Ndyiacom, 25 March 1987 (EBD 24935) , September 1987 (EBD 27485); Bata, 31 August 1986 (EBD 24933) ; Bata, bought at the airport (EBD 20281) ; Punta Mbonda (EBD 334) ; Río Aye, camping of Alena, 13 June 1964 (EBD 2897) .