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| Gehyra corona Kraus, Vahtera & Weijola, 2024 and G. oceanica lineage M6 from nearby islands of the Bismarck Volcanic arc. |
Abstract
The wide-ranging gecko Gehyra oceanica occupies numerous islands across much of the Pacific Ocean basin. Previous work has identified six divergent genetic lineages within lizards assigned to this species. During an expedition to islands off of northern New Guinea we collected lizards of this complex on Crown Island that differ from all other known Gehyra in being sexually dimorphic in colour pattern. We find this population to also be genetically divergent to the other lineages previously identified, as we do with another lineage of populations from nearby islands. Given the unique colour pattern of the Crown Island population, combined with its divergent range of precloacal-femoral pores in males and its phylogenetic uniqueness from other members of this complex, we describe this population as a new species, Gehyra corona sp. nov. currently known only from Crown Island, Papua New Guinea. The discovery of this new species and an additional divergent genetic lineage from within the G. oceanica complex highlights the need for further taxonomic revision of that species complex. It seems likely that the new species we identify will prove endemic to Crown Island, but additional islands from around the Bismarck Sea need survey to establish its full range. Given the undisturbed habitat on most of Crown Island and the low human population there, we suggest that this species’ IUCN Red List conservation status be Least Concern.
Key words: Bismarck Volcanic Arc, Crown Island, dichromatism, endemism, gecko, sexual dimorphism, species complex
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| Holotype of Gehyra corona, UMMZ 247756. (A) dorsal view of head, (B) ventral view of head, (C) pubic region showing precloacal pore series, and (D) left foot. Scale bars = 5 mm. |
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| Fig. 3. Portraits in life of members of Gehyra corona and G. oceanica lineage M6 from nearby islands of the Bismarck Volcanic arc. (A) male G. corona paratype from Crown Island (UMMZ 247754), (B) female G. corona paratype from Crown Island (UMMZ 247755), (C) G. oceanica lineage M6 from Tolokiwa Island (UMMZ 247759), and (D) G. oceanica lineage M6 from Umboi Island (UMMZ 247771). In none of the islands near to Crown Island did we find morphotypes similar to male G. corona. |
Gehyra corona sp. nov.
Diagnosis: An intermediately sized (adult female SVL 75–88 mm, adult male 79–95 mm) species of Gehyra having entirely undivided subterminal lamellae on all toes; 16–19 T4 lamellae; 12–15 T1 lamellae; extensive webbing between all toes; 27–32 precloacal-femoral pores in a continuous row in males; small and subequal subcaudal scales; rounded tail lacking serrations; lateral, antecubital, and popliteal skin folds absent or weakly developed; and colour pattern sexually dimorphic, with males boldly maculated with dark brown dorsally (Fig. 3A) and females grey irregularly suffused with brown and with whitish or pale-grey dots on neck and head (Fig. 3B).
Etymology: The species name is the Latin noun for ‘crown’, named for the sole island from which this species is named.
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| Habitat around the type locality of Gehyra corona on Crown Island from which lizards were collected on tree trunks. |
Ecology: The type series was collected active at night in disturbed low-elevation forest near (but not on) the coast (Fig. 6). All animals came from tree trunks, including on Pandanus (presumably P. tectorius) and Cocos nucifera.
Fred Kraus, Varpu Vahtera and Valter Weijola. 2024. A New insular Species of Gehyra (Squamata: Gekkonidae) from Papua New Guinea closely related to Gehyra oceanica. Systematics and Biodiversity. 22(1); 2404829. DOI: doi.org/10.1080/14772000.2024.2404829
