Torbenwolffia galatheae Zenkevitch 1966

Torbenwolffia galatheae Zenkevitch, 1966 (Fig. 2 D-F)

MATERIAL EXAMINED. — East Equatorial Atlantic Ocean. Gulf of Guniea, BIOZAIRE 3, CP 11, stn ZB-D, 05°50.5840’S, 008°20.0380’E, 3978 m, 20.XII.2003, 1 ♀.

DESCRIPTION

Colour of trunk of preserved specimen is reddishbrown, proboscis missing.Trunk cylindrical, 46 mm long and 15 mm across broadest part. Posterior half of trunk damaged on dorsal side. Rounded papillae densely distributed over entire surface of trunk, aligned roughly in transverse rows, slightly larger in middle region of trunk. Integument is thick and opaque. Single genital pore is located about 5 mm away from anterior end of trunk (Fig. 2D). Ventral setae absent.

Single tubular gonoduct is located on left side of nerve cord (Fig. 2E). Proximal end of gonoduct passes under nerve cord to open in median line. Gonostome basal in position. Gonostomal lip is smooth (Fig. 2E). Anal vesicles consist of two saclike structures covered with tubules terminating in ciliated funnels (Fig. 2F). Anal vesicles open into prominent cloacal bulb.

REMARKS

Distinguishing features of the genus Torbenwolffia include a proboscis with bilobed anterior extremity; no ventral setae; single gonoduct and short unbranched anal vesicles. Torbenwolffia galatheae was described originally by Zenkevitch (1966) based on specimens collected from the Kermadec Trench in the Pacific Ocean. All the specimens were found at great depths. The present specimen closely approaches the description given by Zenkevitch (1966). One minor difference, however, lies in the structure of the anal vesicles, which in the present specimen are two sac-like structures into which open many excretory tubules terminating in ciliated funnels.

In the original description of the species Zenkevitch (1966) has mentioned that the gonoduct is located on the right side. This is incorrect as his illustration clearly shows that this organ is located on the left side of the animal.

Torbenwolffia galatheae was recorded and described by Biseswar (2005). The specimens were collected in the Porcupine Abyssal Plain in the North-East Atlantic at a depth of 4847 m. The discovery of the species in the East Equatorial Atlantic Ocean is a new record for this region and extends its range of distribution.