Stegonotus batjanensis ( Günther, 1865 )

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 : 25-26

Stegonotus batjanensis ( Günther, 1865)

Taxonomic status. Valid.

Synonyms. Leptophis batjanensis Bleeker, 1857:473 (nomen nudum)

Original name. Coluber (Lielaphis) batjanensis Günther 1865:93 . In his fourth list of snakes, Günther placed his new species into a genus he erected to accommodate Coluber holochrous and Spilotes samarensis (see their respective accounts above), two species that have long been in the synonymy of other taxa (with S. modestus and S. muelleri , respectively). Due to the logistical constraints of research at the time, it is doubtful that Günther actually personally examined the type specimens of S. modestus or S. muelleri , the respective taxa in whose synonymy the two putative Lielaphis species were placed. The species epithet references Batjan, an older name for Bacan Island based on Dutch pronunciation, and the description was presented in English.

Holotype. BMNH 1946.1 .11.36 ( Fig. 13 ; Table 1), formerly BMNH 63.12 .4.15, an adult male. The original description included line drawings of the head in dorsal, ventral, and lateral views ( Günther 1865: Plate II, Fig. A).

Type locality. “Batjan” [Bacan Island, North Maluku Province, Indonesia].

Collector. The specimen is listed as having been collected by Pieter Bleeker, but Bleeker never ventured out into the northern Moluccas ( Bleeker 1877; Heiningen 2010). It was most likely sent to London from Batavia as part of Bleeker’s donations, which were assembled from a variety of suppliers. However, since Bleeker departed the Dutch East Indies in the year 1860, the specimen must have been collected before his departure, and likely after his trip through the central Moluccas in 1855, where his interest in the region was kindled ( Bleeker 1856).

Key characteristics of the holotype. The original description includes measurements of an SVL of 61 in and a tail length of 12 in. This converts to 1549 (1280) mm SVL + 305 (300) mm TL = 1854 (1580) mm TTL. V ♂ = 236 (235), SC ♂ = 78 11 (86), SCR ♂ = 0.27; D = O-17-O (17-17-15), SL E = 3+4+5 (3+4+5), SL = 8 (8), IL = 10, counted from the figure in the original description (10), IL G = O (5).

Key characteristics of the species. We were able to examine 28 specimens of S. batjanensis that were collected on one of the four islands to which we are restricting the distribution of the species. Of these, one (the male holotype) was collected on Bacan, 16 (5 ♀♀, 7 ♂♂, four of unknown sex) on Halmahera, four on Morotai (1 ♀, 3 ♂♂), and five on Ternate (2 ♀♀, 2 ♂♂, one of unknown sex). Two additional specimens we examined are clearly members of this species but no locality is available. Characteristics include V ♀ = 203–216 (211 ± 4.5), V ♂ = 221–236 (229 ± 4.3); SC ♀ = 80–90 (84 ± 3.8), SC ♂ = 78–89 (85 ± 3.3); SCR ♀ = 0.28, SCR ♂ = 0.27; D = 17-17-15 (100%); SL E = 3+4+5 (100%); SL = 8 (n = 22, 96%) or rarely 7 (n = 1, 4%); IL = 9 (n = 18, 78%), 10 (n = 4, 17%), or rarely 8 (n = 1, 4%); IL G = 5 (100%). The species displays sexual dimorphism in the non-overlapping ventral

10. Günther (1863a:60) wrote, “If we divide the Colubri with equal or subequal teeth into the subgeneric divisions of Coluber , Elaphis , Cynophis , Spilotes , and Coryphodon , as indicated in my 'Catalogue of Colubrine Snakes,' p. 84, the present species [ Coluber holochrous ] does not enter any of these sections; and we may propose the name of Lielaphis for a sixth group, of which C. holochrous is the type, and to which also Spilotes samarensis, Peters , belongs.” However, in his Catalogue ( Günther 1858:84) these “subgenera” are listed as genera (the term Colubri is not used) and in his third account of new snakes in the British Museum ( Günther 1863b:349) he listed Elaphis as a genus. Whereas the subgeneric divisions in the paper on the Ceram herpetofauna are explicit, we believe the taxon levels are better stated to be the tribe Colubri and a division of the tribe into six genera.

11. Given the large difference between our own count and the value listed by Günther (1865), we believe it most likely that Günther inadvertently reversed his numbers and that his actual count would have been 87, including the now missing tail tip scale.

count. De Lang (2013) listed dorsal counts of “19, 17, or 15-17-15” for the species, citing several literature sources 12. We found only the 17-17-15 count, although there are specimens that display dorsal count oddities, whereby a few dorsal rows have 16 or 18 rows before returning to the regular count of 17.

Comments. Stegonotus batjanensis is a distinctively patterned northern Moluccan regional endemic, whose presence on Bacan, Halmahera, Kasiruta, Morotai, Obi, Ternate, and Tidore is confirmed by voucher specimens (de Lang 2013). We have not seen specimens from Kasiruta, Obi, or Tidore, and we are wondering whether these are the ones with dorsal scale counts that differ from the norm. There are two specimens of S. batjanensis in the collection of the Zoölogisch Museum Amsterdam (ZMA17660A–B) whose locality is given as Ambon (see also de Lang 2013). This locality is incongruent with the expected northern Moluccan range for the species, placing it at least 300 km to the south of confirmed localities, and on the far side of Seram, from which this species is not known. These two specimens were given to the ZMA during the retrenchment of the Koninklijk Instituut voor de Tropen [Royal Tropical Institute] without a named collector based on the collection’s specimen ledger. We believe that the locality “ Ambon ” is in error, and that Ambon, the main center of economic activity in this area of Indonesia, was merely the shipping point of origin for specimens collected in the region. This is not a unique circumstance, as the example of the Timor python ( Malayopython timoriensis ) shows, which was not collected and does not occur on Timor, but was merely shipped from Kupang in West Timor ( Barker & Barker 1996; O’Shea & Kaiser 2018).

12. We interpret this to mean dorsal counts of 19-17-15, 17-17-15, or 15-17-15.

Figures

FIGURE 13. Holotype of Stegonotus batjanensis (Günther 1865), BMNH 1946.1.11.36, an adult male from Bacan Island, North Maluku Province, Indonesia. Shown are the entire specimen (TTL = 1580 mm) in (A) dorsal and (B) ventral views, and its head in (C) dorsal, (D) right lateral, and (E) ventral views.