Cavolinia uncinata (Rang, 1829a) subsp. uncinata (Rang, 1829a) forma roperi Van der Spoel, 1969c
Overview
This is a large uncoiled thecosomatous pteropod, 0.5 cm long. It has prominent brown areas on the shell. It has a rather flat dorsal side with moderately developed ribs. There is no keel along the lateral sides. The caudal spine is strongly curved dorsally and relatively long. The ventral side is clearly vaulted. Shell sculpture consists of faint growth lines and transverse striation near the aperture. The dorsal lip curves over the aperture. Micro-zooplankton and phytoplankton are its food and it is a mucus feeder. It lives in the Atlantic Ocean, at shallow and moderate depths (Cavolinia u.u. roperi).
Taxonomic Description
Shell with dark brown colour patches, lateral spines curved slightly caudad, the long caudal spine is curved strongly dorsal. The shell aperture is narrow, on the ventral surface with a faint hammered structure (Cavolinia u.u. roperi crossing ribs).
Shell length varies between 3.5 and 5.0 mm, its width varies between 3.0 and 4.5 mm.
Juveniles
In Cavolinia u.u. roperi protoconch I has finely transverse striations, protoconch II is less densely striated transversely, protoconch I is usually quickly worn off. The protoconch is blunt ended and quickly diverges. The juveniles are comparable to those of the forma pulsata.
Reproduction
This forma is protandric hermaphrodite.
Ecology
This forma is phytophagous.
Distribution
This forma was only collected in the NW-Atlantic Ocean, see the Cavolinia u.u. roperi map.
Types
Cavolinia uncinata forma roperi Van der Spoel, 1969a: 194, fig. 5.
Holotype: USNM 576977 (alcohol collection). Paratypes: USNM 567977 2 spec. (alcohol collection).
Type locality: 32°16'N 64°18'W Coll.: COPE stat 1-8 C+D.
Etymology: the name is given in honour to Dr. C.F.E. Roper.