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| Tuerkayana latens Ng & Shih, 2023 |
The taxonomy of the gecarcinid land crab Tuerkayana rotundum (Quoy & Gaimard, 1824) is revised. The taxon, the type species of the genus, occurs from the western Indian Ocean to the western Pacific, and varies substantially in colour and various morphological features, but the male first gonopod structure is constant and the extensive genetic data from mitochondrial 16S rDNA, cytochrome c oxidase subunit 1 and control region markers confirms the recognition of one wide-ranging species. Specimens from Tuamotu in French Polynesia and Pitcairn Island, however, differ in having a smoother and slightly more swollen carapace, and significantly, the male first gonopod structure is distinctly different. The genetic data also supports their differentiation. As such, this material is here recognised as a new species, Tuerkayana latens n. sp.
Key words: Land crabs, Gecarcinidae, Tuerkayana latens, New species, Systematics, phylogeny, 16S rDNA, Cytochrome c oxidase subunit 1, Control region, South Pacific, Tuamotu Islands, Pitcaim Islands.
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| Tuerkayana latens n. sp., holotype male (52.8 × 42.7 mm) (MNHN-IU-2011-5594), French Polynesia |
Tuerkayana latens n. sp.
Diagnosis: Frontal region covered with small granules; epigastric, epibranchial and anterior part of
mesobranchial regions with scattered low granules
and low striae, surface appears relatively smoother;
mesogastric, metagastric regions smooth; posterior
part of meso-, metabranchial regions with few oblique
striae and granules; epigastric regions prominent,
margin relatively sharp; postorbital cristae strong,
separated from epigastric by shallow concavity; external
orbital tooth broadly triangular, margin confluent with
anterolateral margin, separated by small cleft (Figs.
3A, B, 7D). Merus of third maxilliped subovate, as
long as wide (Fig. 7C). Surfaces of adult chelae with
low granules on margins, punctate to rugose (Fig. 9D).
Ambulatory legs short; ratios of maximum length
to maximum width of third and fourth ambulatory
meri 2.5, 2.4, respectively; surfaces covered with
striae, appears rugose; dorsal margin of merus rugose,
uneven; lateral margins of propodus, dactylus lined
with strong, stiff spines or setae (Figs. 3A, 10D, H).
Male pleon relatively broad; somite 6 wider than long,
lateral margins strongly convex (Figs. 8G). Adult G1
almost straight, when viewed from ventral perspective;
distal part curved at angle of about 45° from vertical;
distal part of outer margin forming gentle shelf–like
structure; base of the distal part not obviously tapering,
with outer margin gently curving to meet truncate tip in
dorsomesial view, in ventral view, outer margin almost
straight, with flange wide, distinctly developed (Fig.
11D, G, L).
Etymology: The species name is from the Latin word “latens”, for hidden and concealed; alluding to
how the taxon has eluded formal discovery until now.
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| Colours in life of Tuerkayana rotundum (Quoy & Gaimard, 1824). A, male (47.8 × 37.8 mm) (ZRC 2008.506), Panglao Philippines; B, male (37.6 × 29.0 mm) (ZRC 2012.103), Vanuatu; C, male (37.0 × 28.4 mm) (ZRC 2012.103), Vanuatu; D, male, New Caledonia (specimen not collected); E, male (57.6 × 44.5 mm) (ZRC 2013.1074), North Keeling Island, Cocos-Keeling Islands; F, male, Blowholes, Christmas Island (specimen not collected). |
Peter K. L. Ng and Hsi-Te Shih. 2023. Tuerkayana latens, A New Species of Land Crab from French Polynesia, with A Discussion on the Phylogeny of the Genus (Crustacea: Decapoda: Brachyura: Gecarcinidae). Zool Stud. 62:10. DOI:10.6620/ZS.2023.62-10. zoolstud.sinica.edu.tw/Journals/62/62-10.html
