Gehyra rohan OLIVER, CLEGG, FISHER, RICHARDS, TAYLOR & JOCQUE, 2016
Can you confirm these amateur observations of Gehyra rohan?
|Higher Taxa||Gekkonidae, Gekkota, Sauria, Squamata (lizards: geckos)|
|Synonym||Gehyra rohan OLIVER, CLEGG, FISHER, RICHARDS, TAYLOR & JOCQUE 2016|
|Distribution||Papua New Guinea (Manus Island, Los Negros Island, Mussau Island)|
Type locality: near Lorengau, Manus Island, Papua New Guinea (2.0388S, 147.2371E)
|Types||Holotype: RBINS 2684 (Field No. PNG14-88), adult male, collected 3 December 2014 by J. R. Clegg, P. N.Taylor and M. M. T. Jocque.|
Paratypes. AMS R129497–129498, adult females, Lombrum, Los Negros Island, Admiralty Islands, Papua New Guinea (2.01S, 147. 42E), collected 15 December 1951 by N. C. Goddard; CAS 252881, adult female, south bank of Lorengau River, 2.5 km southwest of Lorengau, Manus Island, Papua New Guinea (2.0415S, 147.2594E), collected 30 May 2010 by R. Fisher; PNGNM 25220 (PNG14-158), adult female, Yiringou Village, Manus Island, Papua New Guinea (2.0833S, 147.1167E), collected 9 December 2014 by J. R. Clegg, P. N. Taylor and M. M. T. Jocque); RBINS 2685 (PNG14-157), adult male, Yiringou Village, Manus Island, Papua New Guinea (2.0833S, 147.1167E), collected 9 December 2014 by J. R. Clegg, P. N. Taylor and M. M. T. Jocque; SAMA R69881 (SJR15105), adult male, near Nae, Mussau Island, Papua New Guinea (1.524S, 149.739E), collected 18 October 2015 by K. Aplin.
|Diagnosis||Diagnosis. Gehyra rohan sp. nov. is distinguished from other Gehyra species by the following suite of characters: very large size (adult SVL 130–150 mm), large head (HW/SVL 0.18–0.22, HD/SVL 0.11–0.14), prominent skinfolds on the anterior forelimbs and posterior hind limbs, weak lateral fold, heterogeneous dorsal scalation consisting of large rounded scales bordered by numerous much smaller rounded or triangular scales, massive digital discs with high number of wide undivided subdigital lamellae (finger IV 23–25, toe IV 22–26) that are not deeply notched or divided, rostral with near horizontal dorsal edge and not deeply notched, precloacal and femoral pores in a moderately long single continuous chevron of up to at least 40 pores, original tail without lateral serrations, slightly compressed and with a prominent medial row of enlarged subcaudals, and a prominent ring of orange scales around the eye in life.|
Comparisons. Only four other species of Gehyra approach the large size (adult SVL consistently > 120 mm) of Gehyra rohan sp. nov.: G. georgepottshaasti (Vanuatu), Gehyra marginata Boulenger, 1887 (Maluku), G. membranacruralis (Papua New Guinea) and G. vorax (Fiji). Based on published descriptions (Flecks et al. 2012) and field observations (RNF, SJR and Fred Kraus pers. com.) these taxa all lack a complete, bright orange ring around the eye in life, although occasional specimens of Gehyra vorax do have a yellow contour (as opposed to orange) around the dorsal edge of the eye (RNF pers. obs., for an example see page 172 in Ryan 1998). Gehyra rohan sp. nov. further differs from Gehyra marginata in having enlarged subcaudals under the original tail (versus absent), in having a chestnut brown iris (versus light green), and in having a less prominent ventrolateral dermal fringe on the body; from G. georgepottshaasti in having rounded postmentals (versus distinctly elongate) (Flecks et al. 2012); from Gehyra vorax in having a lower number of femoral pores in adult males (up to 40 versus 58–90) (Beckon 1992); and from Gehyra membranacruralis by its heterogeneous dorsal scalation consisting of large rounded scales separated by numerous much smaller rounded or triangular scales (versus large rounded scales only), and by having larger enlarged subcaudals (maximum anteroposterior length on adults > 2.5 mm versus < 2.5 mm).
All other Gehyra are consistently smaller than Gehyra rohan sp. nov. Gehyra baliola (Duméril, 1851) and Gehyra barea Kopstein, 1926 from New Guinea and surrounding islands are moderately large (max SVL up to at least 105 mm), but Gehyra rohan sp. nov. can be readily distinguished from these taxa by the presence of prominent popliteal folds on the forelimbs (versus not prominent), a rostral that is not or barely notched, and low number of large internasals (versus rostral deeply notched (u-shaped) with a moderate to high number of very small granular internasals). Gehyra serraticauda Skipwith & Oliver 2014 is also large (potentially up to 120 mm SVL), but can be distinguished by the same characters as the preceding two species, in addition to having well-developed tail serrations (Skipwith & Oliver 2014).
The only congener recorded from Manus and Mussau is the widespread taxon Gehyra oceanica, from which Gehyra rohan sp. nov. is readily differentiated by its much larger adult size (> 100 mm versus < 100 mm), having enlarged subcaudals (versus absent), prominent popliteal skinfolds (versus absent), and distinctive orange ring around the eye in life (versus absent). The Gehyra insulensis/mutilata complex is also widespread in the Pacific, but Gehyra rohan sp. nov. is easily distinguished from this species complex by its much larger size (max SVL > 100 versus < 65 mm ), and the absence of minute serrations along the lateral edges of the original tail (versus present).
|Comment||Habitat: largely arboreal; generally found in primary or disturbed lowland tropical rainforest on the trunks of large trees. It is also found on around human habitation in forested areas. Two specimens were found on wooden beams below houses. The holotype was found running across a road in forest at night. The specimen from Mussau was found in a cave in disturbed forest close to the coast.|
|Etymology||Rohan is the Sohoniliu Village (Nali language) ‘tok ples’ (local language) name for this gecko. The community of Sohoniliu Village requested that this name be used for the formal description of this species, and we thank them for their support of this work.|