Corolla ovata (Quoy and Gaimard, 1832)
Overview
This is a shell-less pteropod with a large gelatinous slipper-like pseudoconch, 4 cm long. The pseudoconch is broad-oval. The wings are disc-shaped and the visceral mass forms a dark nucleus embedded in the perfectly transparent pseudoconch. The pseudoconch is rounded at both sides and covered with large warts. The proboscis is prominent. It is an elegant swimmer that feeds with a mucous web in microplankton. It lives in temperate and warm waters of all oceans (Corolla ovata Japan Sea).
Taxonomic Description
Corolla ovata has a slipper-like pseudoconch (Corolla ovata 1, Corolla ovata pseudoconch) which is transparent with a broad cavity occupying the dorsal half and leaving half or more of the "slipper" for the aperture. Tuberculation is rather coarse, irregular, most dense at the dorsal side. The swimming disc is broadly oval and does not reach far beyond the border of the pseudoconch in preserved specimens but it may reach far over this border when alive. The wing musculature consists of a few opaque broad muscle bands forming three separate crossing systems visible in the intact wing. The proboscis is broad and of moderate length reaching the middle of the swimming disc, it bears two symmetrical tentacles and two horns of moderate length. The proboscis is free from the disc surface over nearly its total length (Corolla ovata 2). The mantle gland is slightly asymmetrical with four broad bands, and three narrow transparent bands of which one is incomplete (Corolla ovata mantle). Glands along the wing border are not present. Largest diameter of the swimming disc is 80 mm. Pseudoconch length up to 40 mm.
Juveniles
A special description is not available.
Reproduction
The species is a protandric hermaphrodite.
Ecology
The species is phytophagous and epipelagic. Horizontal swimming speed is 3.5 mm/sec., upward swimming is 3.5 mm/sec and sinking speed is 3.9 mm/sec.
Distribution
Corolla ovata occurs in all oceans between 40°N and 40°S, and is a cosmopolitan warm water species, see the Corolla ovata map. It shows considerable diurnal vertical migration; in the Florida Current Wormelle (1962) found a mean day level at 221 m and a mean night level at 52 m.
Types
Cymbulia ovata Quoy and Gaimard, 1832: 373 (1833), pl. 27, figs. 25-30.
Lectotype: MHNP, animal and pseudoconch prepared (alcohol collection) Paratypes: MHNP, 7 pseudoconchs, 2 complete spec., 2 damaged spec. (alcohol collection).
Type locality: Amboine. Coll.: Quoy and Gaimard.