Pelusios hyneki tanganyika Široký & Fritz, 2025

Pelusios hyneki tanganyika Široký & Fritz subsp. nov.

Tanganyika hinged terrapin

Sternotherus nigricans (non Testudo nigricans Donndorf, 1798 ), Sternfeld & Nieden (1911 as “ Sternothaerus nigricans Smith ”)

Holotype. Zoologische Staatssammlung München ( ZSM 106 View Materials /1960), subadult female in alcohol, Lake Manyara, Mbugwe ( -3.5972, 35.8664), Tanzania, leg. Johann Popp, 22 April 1960 ( Fig. 7 View FIGURE 7 ). GoogleMaps

Paratype. Museum für Naturkunde Berlin ( ZMB 22828 View Materials ), subadult of unknown sex in alcohol, “Unika, Bezirk Langenburg, D.O. Afrika ” (= Unyika, Mbeya District, Tanzania, approx. -8.8900, 33.4651), Hauptmann a. D. Paul Fromm , April 1909 GoogleMaps .

Diagnosis. Pelusios hyneki tanganyika subsp. nov. differs from the nominotypical subspecies in mitochondrial DNA markers, private alleles in the RAG2 and R35 loci, and its allopatric distribution. A selection of diagnostic sites for the mitochondrial cyt b and ND4 genes is listed in Table 2.

Description of holotype. Young female in alcohol, with oval carapacial outline. Right side of carapace with abnormal scutation with “dovetailed” vertebral scutes and five irregular costal scutes. Plastral hindlobe indented at bridge (along abdominal-femoral seam), outer contour of femorals curved, resulting in an emarginated edge at the femoral-anal seam. Anal scutes deeply notched; notch with slightly curved edges. Head retracted. All following values are maximum measurements in straight line: carapacial length 150 mm, carapacial width 117 mm, plastral length 140 mm, and shell height 67 mm. Intergular broad, with slightly diverging edges, length 29 mm, separates the small triangular gular scutes completely. Midseam lengths of the remaining plastral scutes as follows: humerals— 20 mm, pectorals— 5 mm, abdominals— 43 mm, femorals— 26 mm, and anals— 17 mm. Color of carapace olive brownish; basic color of plastron horn yellow with darker brownish suffusions across all shields. Gular, intergular, and anal scutes mainly brownish.

Variation. In contrast to the holotype, the paratype of P. h. tanganyika subsp. nov. has an almost plain yellow plastron. Its straight carapacial length is 87 mm. Unfortunately, no notes or measurements were taken from the three live individuals in the former collection of H. Prokop ( Pardubice) .

Distribution. Only known from two sites in central mainland Tanzania.

Remarks. Geographically, the minimum distance between the genetically verified records of P. h. tanganyika subsp. nov. and the type locality of P. h. hyneki sp. et subsp. nov. is approximately 800 km. If the black hinged terrapins from Tanzania with blotched plastral pattern represent P. subniger sensu stricto ( Fig. 8 View FIGURE 8 ; four iNaturalist records from Iringa and Manyara Regions, see Table S3), P. h. tanganyika subsp. nov. occurs there sympatrically with P. subniger sensu stricto. Together with the photographic records of black hinged terrapins with a diffuse plastral pattern from Botswana, Zambia, and Zimbabwe (Table S3), this suggests that P. subniger sensu stricto is rather a coastal and P. hyneki sp. nov. an inland species (cf. Fig. 8 View FIGURE 8 ).

Etymology. The subspecies epithet is a noun in apposition and refers to the continental part of Tanzania (Tanganyika) from which the taxon is described.