Iles, 1953
Diagnosis
Small rather globose member of the rotundata group. Carapace height about 55-60% of the length, breadth about 45% in both sexes (C. teretivalvata Habitus 1, C. teretivalvata Habitus 3). The ventral margin curves smoothly from below incisure to the postero-dorsal corner. There is some anterior taper. Angle of postero-dorsal corner about 135°. In ventral aspect flanks smoothly curved, maximum breadth in females posterior of mid-length, in males at the mid-length (C. teretivalvata Habitus 2, C. teretivalvata Habitus 4).
Female, frontal organ undifferentiated, capitulum region slightly enlarged, ventrally hirsute, ending in a blunt point (C. teretivalvata 1). First antenna, dorsal seta absent, "a"-"d" setae about half length of "e" seta.
Male, frontal organ stem shorter than first antenna, capitulum, hirsute, swollen ventrally along basal two-thirds, terminally rounded (C. teretivalvata 3). First antenna, the "a" seta minute, "b" and "d" setae subequal, slightly shorter than "e" seta, "e" armature 10 pairs of pointed spines which proximally become more spaced out (C. teretivalvata 4).
Remarks
Müller's (Müller, 1894) original description of C. rotundata confused at least two species, Müller himself identified a long and a short form. Iles, 1953 separated the two size forms in the Benguela Current region, naming and describing the short form C. teretivalvata. The long form he named C. skogsbergi but cited Skogsberg's (Skogsberg, 1920) description as the type description. Confusion prevailed until Gooday, 1981 revised the rotundata complex and distinguished no fewer than eight species which could fit within the concept of C. skogsbergi. Iles's description of C. teretivalvata remained valid for this species which is extremely widespread in its distribution.
Distribution
Recorded from the Atlantic and Pacific Oceans. In Atlantic, it has been recorded from 60°N-29°S. Generally it is shallow mesopelagic in its bathymetric range, but some adults undergo diel vertical migrations into the neuston at night. 1, 2, 3 (R.R.S. Discovery Map).
Type specimens
None designated; status of original material uncertain.
Type locality
None designated, original description based on material collected during the Discovery investigations into the biology of the Benguela Current region off Southwest Africa.