Physical Description

The first thing striking about M. longicarpus is their bright sky blue body.  As well as the distinctive sky blue colour of the carapace, all adult M. longicarpus specimens have a dark red band over each of their four pairs of walking legs, at the first and second join of the appendages and at the join of the Chela to the rest of their body. All Light-blue solider crabs can easily fit in the palm of your hand as their carapace will reach no bigger than 25mm in width and will weigh no more than 12 grams (Farrelly & Greenaway 1987), although many individuals may not reach this size. There is no sexual dimorphism in this species (Davie, 2011).

Distinctive to the Mictyris genus, is the deep globular shaped carapace which is has a greather length than width (David et al. 2010). Another  identifiable morphological characteristic of the Mictyris genus is the broad, exterior maxilliped 3. The buccal cavity of M. longicarpus is oval shaped, large and completely closed off by two rounded, foliaceous maxillipeds 3 (Poore, 2004).  A useful identification tool of determining M. longicarpus from other species of its genus is the less pointed, more sub-pentagonal rostrum located on the cephalothorax (Poore, 2004).

 The dorsal surface has well defined cervical and cardiobranchial grooves which makes the regions of the cephalothorax easily distinct and arched (David et al. 2010). The posterior end of the carapace is bordered by bristles. It does have antennae but they are small. Its eight walking legs are all very slender as is their two chelipeds (David et al. 2010). The chelipeds are elongated and although slight variation, have no significant difference in size, unlike other crustaceans such as the Fiddler Crabs.  The two eyes are exposed and located on the eye stalks on the dorsal surface (David et al. 2011).

All photographs taken by Kate Buchanan at the University of Queensland St Lucia Campus, 2013.