Stegonotus melanolabiatus Ruane et al., 2017:18

Kaiser, Christine M., Kaiser, Hinrich & O’Shea, Mark, 2018, The taxonomic history of Indo-Papuan groundsnakes, genus Stegonotus Duméril et al., 1854 (Colubridae), with some taxonomic revisions and the designation of a neotype for S. parvus (Meyer, 1874), Zootaxa 4512 (1), pp. 1-73 : 58

Stegonotus melanolabiatus Ruane et al., 2017:18

Taxonomic status. Valid.

Synonyms. None.

Original name. Stegonotus melanolabiatus Ruane et al., 2017:18 . The species name is a descriptive adjective formed from the Greek melano and the Latin labia, meaning dark lips. It was selected to highlight the presence of dark coloration on the labial scales. The species description was presented in English.

Type specimens. Holotype: AMS R115343 ( Fig. 33 A–E, Table 1; Ruane et al. 2017: Fig. 7 ), an adult male . Paratypes: AMS R 122906 ( Fig. 33 F–H), an adult male . AMS R115361 ( Fig. 33 I–K), unsexed. Our own examination of this specimen ascertained by the presence of follicles that it is a female . AMS 115320 ( Fig. 33 L–N), unsexed. Our own examination of this specimen ascertained by the presence of the m. retractor penis magnus that it is a male .

Type localities. Holotype: Doido , Chimbu [now Simbu] Province, Papua New Guinea, elev. 1300 m (ca. 6.5500°S, 144.83°E) . Paratypes: AMS R 122906 , Waro , Southern Highlands Province, Papua New Guinea, elev. 550 m (ca. 6.5333°S, 143.18°E) ; AMS R115361 and R115320, Noru , Simbu Province, Papua New Guinea, elev. 1150 m (ca. 6.5833°S, 144.65°E) .

Collection. All type specimens were collected by Stephen C. Donnellan (South Australian Museum, Adelaide, South Australia) and Kenneth P. Aplin (Smithsonian Institution, Washington, D.C., USA) in April and May 1984.

Key characteristics of the type specimens. (1) Holotype, AMS R115343 : 615 (600) mm SVL + 192 (215) mm TL = 807 (815) mm TTL. V ♂ = 197 (200), SC ♂ = 92 (93) , SCR ♂ = 0.32 (0.32), D = 17-17-15 (17-17- 15), SL E = 3+4 (3+4), SL = 7 (7) , IL = 8 (8), IL G = 5 (5). (2) Paratype, AMS R 122906 : 485 (510) mm SVL + 195 (205) mm TL = 680 (715) mm TTL. V ♂ = 186 (190), SC ♂ = 96 (100) , SCR ♂ = 0.34 (0.34), D = O-15-O (15-15-15), SL E = O (3+4), SL = 7 (7) , IL = 8 (8), IL G = O (5). (3) Paratype, AMS R115361 : 630 (652) mm SVL + 210 (222) mm TL = 840 (874) mm TTL. V ♀ = 186 (191), SC ♀ = 89 (89) , SCR ♀ = 0.32 (0.32), D = O- 17-O (17-17-15), SL E = O (3+4), SL = 7 (7) , IL = 8 (8), IL G = O (5). (4) Paratype, AMS R115320 : 648 (638) mm SVL + 235 (243) mm TL = 883 (881) mm TTL. V ♂ = 192 (194), SC ♂ = 94 (95) , SCR ♂ = 0.33 (0.33), D = O-17-O (17-17-15), SL E = O (3+4), SL = 7 (7) , IL = 8 (8), IL G = O (5).

Key characteristics of the species. According to their specimen list, Ruane et al. (2017: Appendix) included ten specimens of S. melanolabiatus in their analysis. These included specimens from a locality in the recently (2012) formed Hela Province (1 ♀, 1 ♂; erroneously listed as from Southern Highlands Province), Simbu Province (2 ♀♀, 3 ♂♂) and Southern Highlands Province (2 ♀♀, 1 ♂). We have examined all of these specimens personally, and while there is general agreement between our data sets, there are three noteworthy differences (those of Ruane et al. are shown in parentheses). Our data show AMS R115360 with 15-15-15 (17-17-15) dorsals, AMS R 122360 with 17-17-15 (15-15-15) dorsals, and AMS R115321 with 7 (8) supralabials and 8 (9) infralabials. The data for supra- and infralabials is readily verified on our photographs of the specimens and is used for the following calculations. The two other data discrepancies are omitted because of their incongruence. Characteristics include V ♀ = 180–191 (184 ± 4.3), V ♂ = 190–201 (196 ± 4.7); SC ♀ = 89–100 (96 ± 4.9), SC ♂ = 93–100 (95 ± 3.3); SCR ♀ = 0.34, SCR ♂ = 0.33; D = 17-17-15 (n = 6, 75%) or 15-15-15 (n = 2, 25%); SL E = 3+4 (100%); SL = 7 (100%); IL = 8 (100%); IL G = 5. Based on the numbers of ventral scales, there appears to be some sexual dimorphism in that character, with females generally possessing a number of ventrals in the 180s (V mean = 184, only one female with V = 191), whereas males have ventral numbers in the 190s or higher (V mean = 196, two males with V ḵ 200). There does not appear to be any sexual dimorphism in the number of subcaudal scales.

Comment. Ruane et al. (2017) considered S. melanolabiatus to be a member of their S. diehli complex.

Figures

FIGURE 7. Holotype of Stegonotus muelleri Duméril et al., 1854, MNHN 848, an adult female from Mindanao Island, The Philippines. Shown are the entire specimen (TTL = 1308 mm) in (A) dorsal and (B) ventral views, and its head in (C) dorsal, (D) right lateral, and (E) ventral views.

FIGURE 33. Type specimens of Stegonotus melanolabiatus Ruane et al., 2017. Photos include views of the entire body of the holotype AMS R115343, an adult male (TTL = 807 mm) in (A) dorsal and (B) ventral views, and of the specimen’s head in (C) dorsal, (D) right lateral, and (E) ventral views. The heads of the paratypes AMS R122906, R115361, and R115320 are shown in dorsal (F,I,L), right lateral (G,J,M), and ventral (H,K,N) views, respectively.