Gelasiminae Miers, 1886

Shih, Hsi-Te, Ng, Peter K. L., Davie, Peter J. F., Schubart, Christoph D., Türkay, Michael, Naderloo, Reza, Jones, Diana & Liu, Min-Yun, 2016, Systematics of the family Ocypodidae Rafinesque, 1815 (Crustacea: Brachyura), based on phylogenetic relationships, with a reorganization of subfamily rankings and a review of the taxonomic status of Uca Leach, 1814, sensu lato and its subgenera, Raffles Bulletin of Zoology 64, pp. 139-175 : 149-151

Subfamily Gelasiminae Miers, 1886

Gelasimiden Nauck, 1880: 8, 17, 23, 64, 66 [not Latinised, invalid for nomenclatural purposes].

Gelasimidae Miers, 1886 : viii. Type genus: Gelasimus Latreille, 1817 .

Diagnosis. Carapace distinctly transverse, trapezoidal, widest between exorbital angles; fronto-orbital distance more than 9/10 of maximum carapace width, front wide to relatively narrow; regions typically indistinct, grooves between regions shallow or indistinct; anterolateral margins slightly arched; orbital floor without or with vestigial tubercle at inner corner adjacent to antennule; eyestalks slender, very long, cornea terminal without any distal ornament; buccal cavern quadrate, not much longer than wide, third maxillipeds completely covering it when closed; ischium and merus of third maxilliped quadrate, fringed with scattered short setae on inner surface; exopod of third maxilliped not concealed by endopod, with flagellum; chelipeds strongly unequal in adult males, both chelipeds small in females, surfaces of male merus, carpus and palm smooth or armed with short spines or low tubercles; first to fourth ambulatory legs with scattered long and/or short setae on ventral surface of merus, propodus and dactylus, never obscuring margins; brush of long setae present between bases of coxae of second and third ambulatory legs, leading into branchial cavity; male pleon with all somites free or somites 4–6 partly or completely fused; pleonal locking mechanism sometimes present.

Remarks. This subfamily contains all the fiddler crabs not otherwise transferred to the revised Ocypodinae . Miers (1886: viii) introduced the family Gelasimidae Miers, 1886 , but this has been long considered to be a junior synonym of Ucinae Dana, 1851 . However, because of the current diagnoses of the genera and present reappraisal, Gelasiminae can now be used; since Uca s. str. is here transferred to the Ocypodinae . As a result, Gelasiminae is now the largest ocypodid subfamily, with nine genera and 94 species, belonging to two groups: 1) the American BF genera Leptuca , Minuca and Petruca ; and 2) the Indo-West Pacific NF genera Gelasimus , Tubuca and Xeruca , and the BF genera Austruca , Cranuca and Paraleptuca ( Figs. 1–3 ).

In Shih et al. (2013b), Leptuca and Minuca were found to form an unresolved clade, but this was to be most likely the result of analysing too few species. However, Shih et al. (2015) and the results of the present study, show both genera have high and medium support, respectively; especially with the removal of the newly recognised Petruca , and generic reassignment of some other species (see below). Australuca , on the other hand, is nested within Tubuca and must therefore be regarded as a junior subjective synonym of that genus (see Remarks under Tubuca ).

A number of species are regarded as nomina dubia by Ng et al. (2008): Gelasimus huttoni Filhol, 1886 ; Gelasimus leptostyla Nutting, 1919 ; Goneplax nitida Desmarest, 1817 (= Gelasima nitida Desmarest, 1822 ); Gelasimus minor Owen, 1839 ; Gelasimus rectilatus Lockington, 1877 ; and Gelasimus rubripes Hombron & Jacquinot, 1846 .

Figures

Fig. 1. A Bayesian inference (BI) tree of the family Ocypodidae and outgroups, based on the combined 28S rRNA, 16S rRNA and COI markers, showing the three clades (three subfamilies), indicated in different colours. The subfamily Gelasiminae is composed of two groups, one is for all Indo-West Pacific fiddler crabs, the other for the American broad-fronted fiddler crabs.

Fig. 2. A Bayesian inference (BI) tree of the family Ocypodidae and outgroups, based on the combined 28S, 16S and COI markers. The solid circle at the node means it is strongly supported by both BI (≥ 90) and ML (≥ 70); and the open circle means only one method is strongly supported. Name of species or genus quoted means it is suggested as a synonym in this study.

Fig. 3. The simplified phylogenetic tree modified from Figs. 1 & 2, with number of species beside or below the taxa/group. The gray boxes mean the genera are not fiddler crabs.