Stegonotus australis ( Günther, 1872:21 ) Kaiser & Kaiser & O’Shea, 2018

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 : 27-28

Stegonotus australis ( Günther, 1872:21) n. comb.

Taxonomic status. Stegonotus australis has heretofore been considered as a synonym of S. cucullatus . We use the following characteristics to differentiate this species from S. cucullatus (whose characteristics we provide in parentheses): (1) the length of the internasal suture is half of internasal width (the rostral invades the internasal area and nearly separates the internasals, with the length of the internasal suture only one tenth of internasal width); (2) the suture formed by the prefrontals and the frontal lies posterior to or is level with the anterior edge of the eyes (anterior to eyes); (3) the posterior edge of the prefrontals is bent forward laterally, forming an angle of 100° (hardly bent, 165°); (4) the line drawn through the two posterolateral vertices of the frontal lies well posterior to the eyes (intersects the eyes); (5) the chin area is separated from true ventral scales (gastrosteges) by three scales in the ventral midline (two scales); (6) nine supralabials (eight); and (7) ten infralabials (nine). Based on these differences, and on the straight-line distance of ca. 1800 km between type localities, we hereby remove Zamenophis australis from the synonymy of S. cucullatus . This population therefore takes the name Stegonotus australis n. comb. The species australis is the type species of the genus Zamenophis Günther, 1872:21 .

Synonyms. Lycodon darnleyensis Macleay, 1877 ; Herbertophis plumbeus Macleay, 1884 .

Original name. Zamenophis australis Günther, 1872:21 . The genus name references Zamenis , a genus of colubrid snakes from Europe and the Middle East, which Günther considered to possess the same suite of characters as his new form. Given the well-defined distribution of Zamenis, Günther (1872) decided to place his new Australian species into a separate genus, using “the entire anal shield” as the single defining characteristic. The genus name is a composite noun, including the genus name Zamenis and the Greek ophis, meaning “a snake like Zamenis . The species epithet could reflect the collecting locality, Australia, or it may have been used in recognition that this was the species of Stegonotus with the most southerly distribution ( australis = Latin, southern). The species description was presented in English.

Holotype. BMNH 1946.1 .14.93, formerly BMNH 68.6 .16.3 ( Fig. 14 ; Table 1), an adult male.

Type locality. “Cape York” [Queensland, Australia]. This locality could either refer to the Cape York Peninsula, a large cone-shaped landmass that juts northwards from the northeastern side of the Australian continent to give its east coast a characteristic horn pointing towards New Guinea, or to Cape York, which is the name for the tip of the peninsula. This tropical peninsula was connected to New Guinea across the Torres Strait for 40,000 of the last 2 million years ( Harris et al. 2008).

Collection. In his account, Günther provided a listing of “the new Species procured and described since June 1868 ” ( Günther 1872:14), which included their provenance. Under the name Zamenophis australis, Günther listed the specimen as having been purchased. Based on information on the original label, the holotype of Z. australis was collected by a “Mr. Higgins,” but no further information is provided. Edmund Thomas Higgins (ca. 1816– 1891) was a London-based dealer in natural history and geological specimens, who traded in Australian wildlife in the 1860s and visited Australia himself twice ( Torrens 1994; Horton et al. 2016). However, it is not possible to restrict the type locality further.

Key characteristics of the holotype. 470 (503) mm SVL + 140 (135) mm TL = 610 (638) mm TTL. V ♂ = 204 (205), SC ♂ = 79 (77), SCR ♂ = 0.28 (0.27), D = O (17-17-15), SL E = 4+5 (4+5), SL = 9 (9), IL = O (10), IL G = O (5).

Key characteristics of the species. In order to avoid any confusion with populations of Stegonotus in the Northern Territories of Australia (the subject of a separate study), we limit our discussion of the species australis to Queensland, the state in which the type locality is located. We were able to examine 35 specimens that, based on their collecting locality and morphological characteristics, could be members of S. australis (11 ♀♀, 20 ♂♂, four of unknown sex). Characteristics include V ♀ = 178–215 (200 ± 11.2), V ♂ = 191–220 (211 ± 6.9); SC ♀ = 69–87 (78 ± 5.7), SC ♂ = 77–88 (83 ± 5.0); SCR ♀ = 0.28, SCR ♂ = 0.28; D = 17-17-15 (100%); SL E = 4+5 (100%); SL = 8 (n = 21, 57%) or 9 (n = 16, 43%); IL = 8 (n = 9, 24%), or 9 (n = 28, 76%); IL G = 5. We note that the standard deviation of the ventral count in females is quite high compared with other species of Stegonotus , and we wonder whether this could indicate that two distinct species may be lumped into our sample.

Comments. The species was synonymized with S. cucullatus by Boulenger (1893).

Figures

FIGURE 14. Holotype of Stegonotus australis (Günther, 1872) new combination, BMNH 1946.1.14.93, an adult male from “Cape York,” Queensland, Australia. Shown are the entire specimen (TTL = 638 mm) in (A) dorsal and (B) ventral views, and its head in (C) dorsal, (D) right lateral, and (E) ventral views.