Cavolinia uncinata (Rang, 1829a) subsp. pulsatapusilla Van der Spoel, 1971a forma pulsatapusilla Van der Spoel, 1971a
Overview
This is for this species a relative small, uncoiled thecosomatous pteropod, 0.6 cm long. It has a flat dorsal side with moderately developed ribs. There is no band at the base of the ventral lip. The caudal spine is curved and long. The ventral side is flat. Shell sculpture consists of faint growth lines and a transverse striation near the aperture. The shell surface shows a strongly hammered structure. The dorsal lip curves over the aperture. Micro-zooplankton and phytoplankton are its food and it is a mucus feeder. It lives in the Red Sea, at shallow and moderate depths (Cavolinia u.p. pulsatapusilla).
Taxonomic Description
Besides the small size, the most typical characters are the long caudal spine which is curved dorsally, the flat dorsal surface and the five less developed dorsal ribs. The lateral spines are directed caudad and the line between the tips of caudal and lateral spines is not regularly curved, but shows a straight middle section.
The shell length is 6.1 mm its width is 4.9 mm.
Juveniles
A special description is not available.
Reproduction
This forma is a protandric hermaphrodite.
Ecology
This forma is phytophagous.
Distribution
This forma is restricted to the central and southern Red Sea, see the Cavolinia u.p. pulsatapusilla map.
Geological Record
This species is known from the Holocene of the Red Sea but probably occurred already in the Riss Glacial.
Types
Cavolinia uncinata pulsatapusilla forma pulsatapusilla Van der Spoel, 1971a: 11, fig. 11.
Holotype: DZTU (dry collection). Paratype: DZTU 12 spec. (dry collection), ZMAN 4 spec. (dry collection).
Type locality: Hawakil Bay 15°18'N 40°23'E. Col.; ISRSE 65-3555 Dr. Ch. Lewinshon.