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Order BATHYNELLACEA Chappuis, 1915


Compiler and date details

Gary C.B. Poore & Helen M. Lew Ton

Introduction

Bathynellaceans are small interstitial crustaceans. Most are from ground water, a few are from sediments in lakes, and members of one genus are found in interstitial beach sands from low salinity to fully saline. They have a vermiform shape, no eyes and simple appendages typical of many interstitial forms; the largest species is 3.4 mm long. The method of reproduction is uncertain but the female lays 1 or 2 large eggs.

The group occurs worldwide. Most of the early literature of the Bathynellacea is written in German but Schminke (1982) and Schram (1986) have provided diagnoses and discussions of biology. The diagnosis here uses these and also that of Coineau (1996). Schminke (1973) recognised two families, both recorded from Australia. He also discussed at length the evolution and biogeography of the Parabathynellidae in particular. Comacho (2006) listed 235 species, a figure since exceeded, and half as many again as the 150 species listed by Schminke (1986) 20 years earlier. Coineau (1996) and Lopretto & Morrone (1998) listed 52 genera, all extant, but the figure is now over 70 genera.

 

Diagnosis

Thoracomere 1 free from cephalon. Pleonites 1-5 separate; pleonite 6 fused to telson; pleotelson with furca. Eyes absent. Antenna 1 inner flagellum minute, with 3 setae. Antennal statocysts absent. Mandibles symmetrical, left incisor fused to an accessory process. Paragnaths present or absent. Thoracopods 1-7 with endopod up to 4-articled, with exopod; thoracopod 8 transformed as copulatory organ in male, more or less reduced in female; epipods present on thoracopods 1-5 or 1-6. Seminal receptacle absent in female. Pleopods 1 and 2 often present, of male not forming a petasma. Uropods not forming a tailfan with telson. Without spermatophores. Seminal receptacle present in female.

 

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)
12-May-2011 12-May-2011 MODIFIED
12-Feb-2010 (import)