Subfamily Planoterginae Stevcic, 1991

Planotergum mirabile [P. Davie 2002: 332]

Museums

Regional Maps

• Planoterginae Stevcic, Z. 1991. Note on some rare and aberrant Australian crabs. The Beagle, Records of the Museums and Art Galleries of the Northern Territory 8(1): 121-134 [124].

  Type genus:

   Planotergum Balss, 1935.

Introduction

The subfamily Planoterginae was erected by Stevcic (1991) to accommodate the monotypic genus Planotergum Balss. The sole species, Planotergum mirabile Balss, 1935, universally is agreed to be highly aberrant for a majid. Serène (1965) discussed the relationships of Planotergum and concluded that it is possibly not majid at all. Griffin & Tranter (1986) tentatively agreed with Serène, noting that the morphology of the male gonopods would be crucial to finally deciding on its relationships. They placed it in the Epialtinae, provisionally, but did not include it in their key to the subfamily. A male crab was finally collected from off north-western Australia, and this was the impetus for Stevcic to describe a new subfamily to accommodate it.

Diagnosis

Carapace irregularly subrectangular, dorsal surface smooth, almost flat. Front lamellar, projecting, rectangular in form, anteriorly straight. Lateral and posterior margins slightly cristiform. Anterolateral margin with four unequal lobes. Posterior margin broadly convex. Antennulae slightly oblique. Antennae with short, broad, immovable basal (2+3) segment; fourth article lamellar, long, quadrangular; fifth article lamellar, but very small; flagellum short. Eyestalks short, stout; cornea well developed and visible in dorsal view. Orbits incomplete; supra-orbital eave of moderate size, pre-orbital tubercle inconspicuous; postorbital tubercle small, separated from supra-orbital eave, and anteriorly cupped for eye protection. Subocular margin reduced. Epistome reduced. Third maxillipeds slender, not completely covering the buccal cavern. Chelipeds minute, asymmetrical, not visible in dorsal view. Walking legs short with only basal part covered by carapace, distal segments in same plane as carapace; cristiform; carpus and propodus tightly pressed against merus; dactyli short, slender, transformed into corneous claw. Merus of first pair of walking legs with small hollow for ocular protection. Female abdomen very wide; male abdomen narrow; telson very reduced in both sexes. (After Stevcic 1991).

General References

Griffin, D.J.G. & Tranter, H. 1986. The Decapoda Brachyura of the Siboga Expedition. Part VIII. Majidae. Siboga Expéditie Monographie 39(c4): 1-335, 112 text-figs 22 pls

Serène, R. 1965. Note sur un Oxyrhynche (Brachyura, Decapoda, Crustacea) aberrant du Sud-Est Asiatique. Bulletin de la Société Zoologique de France 90(4): 457-468 figs 1-4 pls 1-2

Stevcic, Z. 1991. Note on some rare and aberrant Australian crabs. The Beagle, Records of the Museums and Art Galleries of the Northern Territory 8(1): 121-134

History of changes