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| A member of the Goniurisaurus kuroiwae Group |
Kuroiwa’s Leopard Gecko, Goniurosaurus
kuroiwae is a eublepharid gecko endemic to the central part of the Ryukyu
Archipelago of Japan, in the subtropical northwestern Pacific. It is isolated
from the rest of its congeners occurring in southeastern continental China,
northern Vietnam, and adjacent coastal
islands, and the species represents the easternmost Old World member of the
family. Because this species (or species complex) consists of a number of
allopatric and apparently diagnosable divergent insular populations, and its classification
has been controversal.
In the latest revision, its
populations were combined into a single species comprising five extant
subspecies: G. k. kuroiwae; G. k. orientalis;
G. k. splendens; G. k. toyamai; and G.
k. yamashinae. Grismer et al. (1999, 2002), adopted the
evolutionary species concept, referred to each of these taxa as full
species, and this taxonomic treatment has been widely accepted in the context
of the recent trend of disuse of the subspecies rank by herpetologists.
However, Nakamura et al. (2014) believe that such changes in
taxonomic rank are premature, because diagnostic characters originally proposed
to define each of these taxa are few in number and, moreover, include those
with highly variable character states. For example, yellow-brown to gold iris color
was considered as one of the character states that discriminates G. k.
yamashinae from the other subspecies whose irises are blood-red in color,
but G. k. kuroiwae populations from Okinawajima and adjacent islets also
include individuals with more or less yellow irises. They therefore prefer to
take a conservative stance with respect to the taxonomic treatment of G.
kuroiwae sensu lato by maintaining the framework of Grismer et al. (1994).
In a new paper Nakamura and
colleagues (2014) describe a new subspecies of the Kuroiwa’s Leopard Gecko, Goniurosaurus
kuroiwae yunnu, based upon remains from a midden after
the population has apparently become extinct. The new taxon differs from the
other conspecific subspecies in having a unique combination of osteological
character states: in particular, the maxilla contains a posteriorly extended
maxillary shelf and a scarcely inclined lateral wall above the posterior tooth
row, and the frontal contains a widened anterior section and a laterally
overhanging anterior part of lateral prefrontal facet, both of which
differentiate this new subspecies from the morphologically most similar G.
k. kuroiwae. The new subspecies, endemic to Yoronjima Island, may
have gone extinct, together with several other amphibians and reptiles on the
island. The extinction was most likely due to human-related deforestation and
increased predation pressure from introduced weasels.
Citations
Grismer, L.L., Ota, H., Tanaka, S. (1994): Phylogeny,
classification, and biogeography of Goniurosaurus kuroiwae (Squamata:
Eublepharidae) from the Ryukyu Archipelago, Japan, with description of a new
subspecies. Zool. Sci. 11:
319-335.
Grismer, L.L., Viets, B.E., Boyle, L.J. (1999): Two
new continental species of Goniurosaurus (Squamata: Eublepharidae) with
a phylogeny and evolutionary classification of the genus. J. Herpetol. 33: 382-393.
Grismer, L.L., Shi, H., Orlov, N.L., Ananjeva, N.B. (2002):
A new species of Goniurosaurus (Squamata: Eublepharidae) from Hainan
Island, China. J. Herpetol. 36:
217-224.
Nakamura, Y.,
Takahashi, A., & Ota, H. (2013). Recent cryptic extinction of squamate
reptiles on Yoronjima Island of the Ryukyu Archipelago, Japan, inferred from
garbage dump remains. Acta Herpetologica, 8(1), 19-34.