Stegonotus dorsalis Werner 1924
Creators: name: Kaiser, Christine M.
name: Kaiser, Hinrich
name: O'Shea, Mark
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Colubridae
Stegonotus
Stegonotus dorsalis

description: Stegonotus dorsalis Werner, 1924:32
Taxonomic status. Wallach et al. (2014) listed S. dorsalis in the synonymy of S. diehli without further comment. Werner (1924) himself stated at the beginning of his description that he considered this species “nächstverwandt” [sister species] to S. diehli but provided a definitive series of differentiating characteristics. Based on the understanding of Stegonotus we have gained by examining nearly 1500 museum specimens, we consider the characteristics differentiating S. dorsalis from S. diehli, in addition to the uncertain taxonomy of the latter, sufficient to uphold a taxonomic distinction at the species level. None of the well-defined taxa in the genus Stegonotus (S. batjanensis, S. guentheri, S. heterurus, S. keyensis, S. modestus, S. muelleri) display ventral scales of sexes combined with a range of 29 scales (179 in the holotype of S. diehli to 208 in the holotype of S. dorsalis), which already provides strong evidence for species-level distinction. Furthermore, differences include (features of S. diehli provided in parentheses) SL = 8 (7), SL E = 4+5 (3+4), and IL G = 5 (4). We therefore remove S. dorsalis from the synonymy of S. diehli.
Synonyms. None.
Original name. Stegonotus dorsalis Werner, 1924:32. Franz Werner (1867–1939; Fig. 17J) was an Austrian herpetologist and entomologist, as well as lecturer and professor at the Institute for Zoology at the University of Vienna from 1891–1933. It is noteworthy that Werner was initially unable to use specimens at the NMW for his research, having been barred by Franz Steindachner (1834–1919), the then-curator. However, after Steindachner’s death, these restrictions appear to have been loosened, as attested by Werner’s description of S. dorsalis. The undated portrait of Werner (Fig. 17J; public domain) was taken by the Viennese portrait photographer Albin Kobé (1884–1963) and hangs in the office of the herpetology curator at the NMW.
Holotype. NMW 14861 (Fig. 27; Table 1), an adult male.
Type locality. Neither jar label nor specimen catalog entry provide any information regarding the type locality. The historic jar label states “Fundort?” [locality?], indicating that no information about the type locality appeared to be available at the time the specimen was accessioned into the collection. However, based on the specimens included in Werner’s (1924) account of snakes in the Vienna museum it becomes clear that the only possible origin for specimens of Stegonotus housed there is New Guinea. Furthermore, the only zoological collection in New Guinea that would have found its way exclusively into the Vienna museum was made by the anthropologist and explorer Rudolf Pöch (1870–1921; Fig. 17K), later a professor of anthropology at Vienna University, who spent several months in New Guinea in 1904 (28 July–25 November; Pöch 1907, 1908), and whose name is associated with the (falsely identified) specimen of “ Stegonotus modestus ” that Werner (1924) included in his account. Further research we conducted in the archives of the Vienna collection led to the discovery of historic specimen inventory slips indicating New Guinea as the collection locality, as well as letters from Pöch to the then-curator, Franz Steindachner, in which the former recounts some of his travels. In one of these letters, Pöch wrote that specimens that had been sent without any specific locality information (i.e., those merely listing New Guinea) were all collected at “Monumbo, Küstenstrich von Potsdamhafen, Deutsch-Neu-Guinea” [Monumbo, in the coastal region around Potsdamhafen, German New Guinea, now Papua New Guinea]. A notation in the margin of the letter reveals that one package of specimens from this area was indeed inventoried. Alas, modern maps and gazetteers of Papua New Guinea show neither Monumbo nor Potsdamhafen.
German maps of the early 1900s and, specifically, one created by Pöch himself in accordance with the Deutscher Kolonialatlas [German colonial atlas] (see Pöch 1908), reveal that the location of Potsdamhafen was in a small bay across from Manam Island, Madang Province, Papua New Guinea (ca. 4.2280°S, 144.9333°E). Pöch’s map and text also show that he used the term “Monumbo” for both a New Guinean tribe and the mountains bordering Potsdamhafen on the landward side. Pöch made several excursions into and through these mountains and included some biological aspects of his surveys in his travelogue (Pöch 1908). The image of Pöch (Fig. 17K; licensed under CC-BY-SA-4.0) is from the photographic collection of the archives at the University of Vienna, Austria.
Collection. The label affixed to the jar lists only the comment “Coll.?” [collector?], indicating that no information was available. The most likely scenario for the collection of the holotype of Stegonotus dorsalis is that Pöch encountered the snake on one of his forays into the interior during the months of August–November 1904. With no opportunity to specify a locality on these expeditions, and with a focus on anthropological research, Pöch could have grouped his collected zoological specimens and provided the general locality of Monumbo for any specimens from the area inland of Potsdamhafen. The type locality of S. dorsalis (see below) is ca. 160 km NW of the type locality of S. diehli, across the mountains of the Adelbert Range.
Key characteristics of the holotype. 805 (805) mm SVL + 245 (245) mm TL = 1050 (1050) mm TTL. V ♂ = 208 (208), SC ♂ = 88 (88), SCR ♂ = 0.30 (0.30), D = O-15-O (15-15-15), SL E = 4+5 (4+5), SL = 8 (8), IL = O (10), IL G = O (5).
Key characteristics of the species. With only a single specimen available, any species-level characterization must remain very general. It appears that S. dorsalis has a relatively high ventral count (V = 208) compared to other species with 15 middorsal scale rows (S. diehli, S. guentheri), whose counts reach only the mid-190s. Other characteristics include SL E = 4+5, IL G = 5, and a relatively high IL count (10).
Comment. This species was not mentioned in the works of McDowell (1972) and Ruane et al. (2017).
description: Published as part of 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), pp. 1-73 in Zootaxa 4512 (1) on pages 48-49, DOI: 10.11646/zootaxa.4512.1.1, http://zenodo.org/record/2607575