Family MATUTIDAE De Haan, 1835

<em>Izanami inermis</em> [from Miers 1884: pl. 26 fig. C]

Izanami inermis [from Miers 1884: pl. 26 fig. C]

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Family MATUTIDAE De Haan, 1835

Compiler and date details

May 2012 - Peter Davie, Queensland Museum, Brisbane

Matutidae De Haan, W. 1835. Crustacea. 1-243 pls A-J, L-Q, 1-55, circ. tab. 2 in Von Siebold, P.F. (ed.). Fauna Japonica sive Descriptio Animalium, quae in Itinere per Japoniam, Jussu et Auspiciis Superiorum, qui Summum in India Batava Imperium Tenent, Suscepto, Annis 1823–1830 Collegit, Notis, Observationibus et Adumbrationibus Illustravit. Leiden : Lugundi-Batavorum. [published from 1833–1850] [36] [as Matutoidea].

Introduction

The Matutidae is a small family of aggressive predatory crabs. Matutids are easily recognised by their circular carapaces, which often are armed with sharp lateral spines, and by the flattened, lanceolate dactyli on the walking legs which enable them to swim efficiently and rapidly, and also to bury themselves quickly in the soft sandy substrates that they prefer to inhabit.

Historically, the Matutinae comprised a single easily recognised genus Matuta. However, Matuta was revised thoroughly by Galil & Clark (1994) who split it into four genera, three of which are found in the Indo-west Pacific region. They also provided a key to all species. Tyndale-Biscoe & George (1962) perhaps deal best with Australian Matuta (sensu lato), but their work should be consulted with care as the names of several species changed following Galil & Clark's (1994) revision.

The Matutinae was long considered to be a subfamily of the Calappidae. As discussed under the introduction to Calappidae, the relationships of what were considered its three subfamilies (Calappinae, Matutinae and Orithyinae) have been questioned in recent years. Števcic (1983) provided good evidence that it is a separate, well-delimited family. Subsequently, following a thorough cladistic analysis of the whole group, Bellwood (1996) also concluded that the Matutidae warranted family status, and indeed is more closely allied to Leucosiidae than to Calappidae.

Diagnosis

Carapace circular; usually armed with a more or less produced, strong lateral spine at junction of antero- and posterolateral margins; front narrow; antennae rudimentary. Third maxilliped elongate, pointed apically, completely covering buccal cavern, and concealing palp when folded; exopodite widest proximally, tapered to a point distally, flagellum absent. Chelipeds subequal, robust; fingers pointed; outer and upper faces of palm variously armed with spines, lobes, or crests. Walking legs natatorial; dactyli more or less lanceolate, last pair broader and more paddle-like. Male abdomen with five segments. Female openings sternal; male openings coxal. First male gonopod (G1) robust, elongate, tapered, apically rounded; G2 thin, longer than G1, with flagellum variously curled, curved or crotchet-shaped.