Eubonellia longistomum DattaGupta 1981

Eubonellia longistomum DattaGupta, 1981 (Fig. 4D, E)

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

DESCRIPTION

Colour of proboscis of preserved specimen is cream, trunk is light pink. Only basal stump of proboscis is attached to trunk, rest is missing. Lateral margins of proboscis curl inwards and unite at proximal end forming narrow lower lip ventral to mouth (Fig. 4D). Only about 25 mm of anterior end of trunk is intact, posterior part missing. Trunk is cylindrical, 10 mm across broadest part. Integument is smooth and devoid of papillae, single genital pore is located a few millimetres away from anterior tip of trunk (Fig. 4D). Ventral setae absent.

Except for foregut, nerve cord and gonoduct, rest of internal organs missing. Single, sac-like gonoduct is located on right side of nerve cord (Fig. 4E). Gonostome distal in position, gonostomal lip with small lobes around margin (Fig. 4E).

REMARKS

Distinguishing features of the genus Eubonellia include a well-developed bifurcate proboscis; absence of ventral setae; single gonoduct on right side of nerve cord with terminal gonostome; anal vesicles are tubular.

The species E. longistomum is described originally by DattaGupta (1981) based on specimens in which the distal ends of the probosces were missing. This species was later recorded and redescribed by Biseswar (2005) from specimens collected from the Porcupine Abyssal Plain in the North-East Atlantic. The present specimen from the east Equatorial Atlantic is incomplete. However, it conforms with the description given by DattaGupta (1981) in all essential respects except for minor differences in the structure of the proboscis. The discovery of E. longistomum in the East Equatorial Atlantic is a new record for this region and extends its range of distribution.