Stegonotus guentheri Boulenger, 1895 :31

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 : 41

Stegonotus guentheri Boulenger, 1895:31

Taxonomic status. Valid.

Synonyms. None.

Original name. Stegonotus Guentheri Boulenger, 1895:31 . Boulenger (1895) named this species for Albert Günther (see the account of Coluber holochrous above), his predecessor at the British Museum of Natural History. The species description was presented in English.

Syntypes. BMNH 1946.1.11.37–38 (formerly 95.4.26.47–48), an adult male and an adult female, respectively, and 1946.1.11.39 (formerly BMNH 95.4.26.49), an adult female ( Fig. 23 ) .

Type locality. “Fergusson Island, D’Entrecasteaux Group, British New Guinea ” [Milne Bay Province, Papua New Guinea; ca. 9.54°S, 150.67°E].

Collection. The collection from which Boulenger obtained these specimens was made by the English naturalist Albert Stewart Meek (1871–1943; Fig. 17G ), who visited the D’Entrecasteaux Archipelago in 1894–95. In reports on Meek’s exploits in the region ( Hartert 1895; Rothschild & Hartert 1896; Meek 1913; O’Shea & Kaiser 2018), the earliest date listed for discoveries on Fergusson is September 1894, the latest June 1895. Meek decamped from Fergusson after a 4-month stay (likely in January 1895) and traveled to Samarai Island, the British administrative center at the time, in order to reprovision and dispatch his specimens to London ( Meek 1913). Given that the description of S. guentheri appeared in the July 1895 issue of the Annals and Magazine of Natural History, this leaves enough time for the collection to reach the BMNH. Later collections on Fergusson during 1895 would not have had sufficient transit time for shipping to the United Kingdom. The specimens therefore must have been collected during Meek’s initial 4-month stay on Fergusson, during the months of September–December 1894. The undated photograph of Meek ( Fig. 17G ; public domain) was also published by D’Abrera (2003).

Key characteristics of the type specimens. (1) BMNH 1946.1.11.37: 920 (929) mm SVL + 230 (234) mm TL = 1150 (1163) mm TTL. V ♂ = 197 (196), SC ♂ = O (69+), SCR ♂ = O (O), D = O-15-O (15-15-13), SL E = 4+5 (4+5), SL = 8 (8), IL = O (9), IL G = O (5). (2) BMNH 1946.1.11.38: x (683) mm SVL + O (165) mm TL = O (848) mm TTL. V ♂ = O (192), SC ♂ = O (64), SCR ♂ = O (0.25), D = O-15-O (15-15-13), SL E = O (4+5), SL = O (8), IL = O (9), IL G = O (4). (3) BMNH 1946.1.11.39: O (647) mm SVL + O (201) mm TL = O (848) mm TTL. V ♀ = O (185), SC ♀ = 75 (78), SCR ♀ = O (0.30), D = O-15-O (15-15-13), SL E = O (4+5), SL = O (8), IL = O (9), IL G = O (5).

Key characteristics of the species. We have been able to examine 38 specimens of S. guentheri . Of these, 37 were collected in the D’Entrecasteaux Archipelago, eight (3 ♀♀, 5 ♂♂) on Fergusson Island, 16 on Normanby Island (3 ♀♀, 13 ♂♂), and 13 (3 ♀♀, 10 ♂♂) without further locality data. One male was collected on Kuia [Kuyau] Island in the Trobriand Islands, ca. 90 km north of Fergusson. Characteristics include V ♀ = 174–198 (187 ± 6.4), V ♂ = 185–198 (191 ± 3.5); SC ♀ = 64–80 (74 ± 4.9), SC ♂ = 64–80 (73 ± 4.3); SCR ♀ = 0.28, SCR ♂ = 0.28; D = 15-15-13 (100%); SL E = 4+5 (n = 37, 97%) or, rarely, 3+4 (n = 1, 3%); SL = 8 (n = 38, 97%) or 7 (n = 1, 3%); IL = 9 (100%); IL G = 5. A key difference between S. guentheri and all other species of Stegonotus is the number of dorsal scale rows, which diminishes from 15 to 13 along the body. There is no other species of Stegonotus with 15- 15-13 dorsal rows; S. diehli and S. dorsalis (see below) have 15-15-15 rows. There does not appear to be any sexual dimorphism when considering the numbers of ventrals or subcaudals.

Comments. In the interest of nomenclatural stability, we hereby designate BMNH 1946.1.11.38 ( Fig. 23 A–E; Table 1) as the lectotype of S. guentheri (Code, Article 74.7). This specimen is a female syntype with a complete tail. This renders BMNH 1946.1 .11.37 and 1946.1.11.39 as paralectotypes .

In the D’Entrecasteaux Archipelago, the distribution of S. guentheri appears to be limited to Fergusson and Normanby Islands, the two largest islands. The species has not been recorded from Goodenough Island, the third larger island in the group. One specimen (AMS 86835) that fits the characteristics of S. guentheri was collected farther afield, on Kuia Island (variant spellings include Kuyau and Kuiao; Austen 1939; Fitzer & Geelan 1956; Hensley & Allen 1977), a small island in the Trobriand Islands to the north.

Figures

FIGURE 17. Selected 19 th and 20 th Century authors and collectors of Stegonotus species. (A) Giacomo Doria (1840–1913), author of the species names aruensis and keyensis. (B) Odoardo Beccari (1843–1920), collector of the Stegonotus aruensis and S. keyensis type specimens. (C) William Macleay (1820–1891), author of the genus name Herbertophis and the species names darnleyensis and plumbeus. (D) John Archibald Boyd (1846–1926), collector of the Herbertophis plumbeus holotype. (E) George Albert Boulenger (1858–1937), author of the species names guentheri, heterurus, and reticulatus. Image licensed for use, © National Portrait Galley, London, United Kingdom. (F) The Reverend George Brown (1835–1917), collector of the Stegonotus heterurus syntypes from Duke of York Island. (G) Albert Stewart Meek (1871–1943), collector of the Stegonotus guentheri and S. reticulatus syntypes. (H) Wilhelm Adolfovich Lindholm (1874–1935), author of the species name diehli. (I) Nelly de Rooij (1883–1964), author of the species name florensis. (J) Franz Werner (1867–1939), author of the species names dorsalis and poechi. (K) Rudolf Pöch (1870–1921), collector of the Stegonotus dorsalis and S. poechi holotypes, and in whose honor the latter was named. (L) Lothar Forcart (1902–1990), author of the species name sutteri.

FIGURE 23. Type specimens of Stegonotus guentheri Boulenger, 1895. Photos include views of the entire body of the lectotype BMNH 1946.1.11.38, an adult female (TTL = 848 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 paralectotypes BMNH 1946.1.11.37 and 1946.1.11.39 are shown in dorsal (F,I), right lateral (G,J), and ventral (H,K) views, respectively.