Sluiterina sibogae

Sluiterina sibogae (Sluiter, 1902) (Fig. 3E, F)

MATERIAL EXAMINED. — East Equatorial Atlantic Ocean. Gulf of Guinea, BIOZAIRE 3, CP 10, stn ZB-D, 5°50.6300’S, 8°20.0600’E, 3977 m, 19.XII.2003, 2 ♀♀. — CP 17, stn R 3, 5°48.6960’S, 9°43.9829’E, 3156 m, 30.XII.2003, 5 ♀♀. — CP 11, stn ZB-D, 5°50.5840’S, 8°20.0380’E, 3978 m, 20.XII.2003, 3 ♀♀. — CP 12, stn ZB-D, 5°50.2300’S, 8°20.2385’E, 3975 m, 20.XII.2003, 9 ♀♀. — CP 24, stn ZB-R, 5°55.143’S, 009°41.6068’E, 3230 m, 4.I.2004, 10♀♀. — CP 21, stn R 9, 05°47.4990’S, 009°43.8038’E, 3130 m, 3.I.2004, 5 ♀♀. — CP 23, stn R 11, 05°45.9180’S, 009°43.9860’E, 3147 m, 3.I.2004, 3 ♀♀. — CP 18, stn R 4, 05°48.1530’S, 009°43.9136’E, 3142 m, 30.XII.2004, 7 ♀♀.

DESCRIPTION

Colour of proboscis and trunk of preserved specimens is reddish-brown. Proboscis is truncate, 19-41 mm long, anterior half is flat and tapers distally (Fig.3E). At proximal end, lateral margins of proboscis curl inwards and unite forming funnel around mouth (Fig. 3E).Trunk is cylindrical, 51-97 mm in length and 10-17 mm across broadest part. Integument is thick and opaque at extremities of trunk but much thinner in middle region.In some specimens anterior end of trunk has transverse wrinkles. Papillae round to oval, densely arranged at anterior and posterior ends of trunk, aligned roughly in transverse rows. Ventral setae absent. Single genital pore is located at tip of conical eminence of body wall a few millimetres away from anterior end of trunk (Fig. 3E).

Gonoduct single, sac-like or tubular, located on left side of nerve cord, with round eggs in sexually mature specimens (Fig. 3F). Gonostome basal in position, gonostomal lip with minute lobes around margin (Fig. 3F). Gut contents moulded into oval faecal pellets. Blood system also damaged due to poor preservation. Anal vesicles are two elongated tubular sacs covered with branched tubules terminating in ciliated funnels.

REMARKS

The species Sluiterina sibogae was originally described from a single female from Indonesia collected at a depth of 4391 m. The present specimens from the East Equatorial Atlantic Ocean closely approach the descriptions given by Sluiter (1902). Similarities are evident in the structure of the proboscis, the position of the gonostome and the distribution of the dermal papillae. The anal vesicles have not been described by Sluiter (1902). In the present specimens the anal vesicles are two sac-like structures bearing branched tubules terminating in ciliated funnels. Sluiterina sibogae was redescribed by Biseswar (2005). The specimen was collected in the Porcupine Abyssal Plain in the North-East Atlantic at a depth of 4839 m. The discovery of this species in the East Equatorial Atlantic Ocean is a new record and which considerably extends its range of distribution.