Female Pinnixa tubicola, found intertidally at March Point, Padilla Bay, by Sarah Bewley and Melissa Moxey along with terebellind tubeworms. Carapace width 7 mm. (Photo by: Dave Cowles, June 2012)
The dactyls are strongly curved. Setae on legs 3 and 4, especially on the dorsal edge of the merus, are long and featherlike. According to Hart (1982), the legs of gravid females have few setae while males and non-gravid females have many more setae (which may be used for swimming), plus hard carapaces. Hard individuals (mature males and non-gravid females) have more opaque carapaces, flatter legs, more long setae on the legs, and red articulations on the carapace. This individual seems intermediate between these conditions. This closeup dorsal view of the carapace shows the egg clusters in the gill chamber. The dorsal longitudinal grooves extending back from the orbits as well as the transverse groove can also be seen.
This ventral view shows the larger cluster of eggs carried on the abdomen, as is normal for Brachyuran crabs (and other members of Suborder Pleocyemata). I have not heard reports of other brachyuran crabs which have some of their eggs up in the gill chambers, as this individual does. Also, several references state that in gravid females the abdomen is wider than the carapace, but that is not true of this individual. Johnson and Snook (1955) state that the propodus has two rows of setae on the ventral side. The outer row extends to the base of the fixed finger while the inner row extends to the tip. Those rows can be seen here.
