Carapace shape with its anterior taper similar to C. macroprocera (Conchoecia macroprocera). The shoulder vaults well developed, clearly seen in profile (C. procera Habitus 1, C. procera Habitus 4). Ventral margin curves smoothly from below the incisure into the posterior margin, interrupted on the right valve by a notch marking the opening of the right asymmetrical gland, just anterior the postero-ventral corner. Postero-dorsal corner right-angled with a small, distinct spine on the right valve. Left asymmetrical gland opening just anterior to the hind end of the hinge.
Female, frontal organ undifferentiated, straight, over three times length of first antenna, capitulum region with a few spinules on its underside, ending in a blunt point (C. procera 1). First antenna segmentation and dorsal seta lacking. Second antenna endopodite, second podomere densely hirsute (C. procera 2).
Male, frontal organ capitulum with a single line of hairs laterally and a medial patch ventrally (C. procera 3). First antenna "e" seta armature 17 pairs of long, straight, slender spines (C. procera 4).
Species is similar to C. macroprocera (Conchoecia macroprocera), but is distinguished by being smaller, the spine on the right valve at the postero-dorsal corner, the male first antenna "e" seta armature having fewer pairs of spines, and the female second antenna endopodite a hirsute second podomere. This species abounds at latitudes <40°; appears in southern U.K. waters in the summer after the establishment of thermal stratification, probably as a result of advection.
Epipelagic to shallow mesopelagic (50-400m) in all oceans. Sometimes even caught in the neuston at latitudes <40°. Range in Atlantic 53°N-40°S. 1, 2 (R.R.S. Discovery Map).
None designated; status of original material uncertain.
The species was initially established by Müller, 1894 to correct confusion between this species and C. oblonga (Conchoecia oblonga)under C. variabilis Müller 1890. The original material of C. variabilis was collected in the Mediterranean Sea. The exact status of the original description is further confused by Angel, 1971 distinguishing three sibling species which fitted within the original concept of C. procera ; the name was retained for the species which best fitted material from the Mediterranean.
None designated, original material probably from the Mediterranean.