Australian Biological Resources Study

Australian Faunal Directory

<em>Dynomene pilumnoides</em> [from Alcock 1900: pl. 1 fig. 2]

Dynomene pilumnoides [from Alcock 1900: pl. 1 fig. 2]

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Family DYNOMENIDAE Ortmann, 1892


Compiler and date details

May 2012 - Peter Davie, Queensland Museum, Brisbane

Introduction

Dynomenids are a small group of 'primitive' crabs living in tropical and warmer parts of the Atlantic, Indian and Pacific Oceans (McLay 1999). They are immediately recognisable by their broad, triangular, frontal margins. Most are shallow water reef-dwelling forms, although one species has been recorded to 540 metres depth. McLay (1999) revised the family and provided keys to genera and species, as well as extensive discussion on morphology, evolutionary relationships, and biology.

 

Diagnosis

Carapace typically wider than long, sometimes longer than wide, moderately convex; surface smooth spinous or areolate, usually densely covered in setae; lateral borders distinct, armed with teeth. Front broadly triangular, continuous, unarmed; frontal groove well marked, split posteriorly; cervical, postcervical, and branchial grooves present. Lateral linea present. Orbital, antennular and antennal fossae defined. Antennule can be concealed inside orbit at base of eyestalk. Third maxillipeds operculiform; completely covering buccal cavern; separated at bases by plate at same level as sternum; basis and ischium of endopod fused, but joint marked by shallow groove. Sternal sutures 7/8 of female end well apart on low tubercles behind bases of second walking legs. Chelipeds equal, stout; fingers hollowed and dented at tip. Last pair of legs reduced, dactyl rudimentary, with obsolete subchelate mechanism. Gills usually 19 (including six podobranchs) plus seven epipods; gill structure phyllobranchiate, but plates variable in shape with different numbers of epibranchial lobes. Abdomen 7-segmented (including telson), without pleurae; both sexes with five pairs of pleopods, first pair vestigial in female, last three pairs rudimentary in male. Telson much wider than long; retaining mechanism for abdomen usually present, but not effective. Uropods present as well-developed dorsal plates. Spermathecal apertures small and rounded, at level of genital openings. Coxa of P5 strongly modified by the penis. Male first gonopod with apical plate. (After McLay 1999).

 

History of changes

Note that this list may be incomplete for dates prior to September 2013.
Published As part of group Action Date Action Type Compiler(s)
04-Jun-2012 04-Jun-2012 MOVED
10-May-2012 10-May-2012 MODIFIED
12-Feb-2010 (import)