68 



T.G. PILLAI AND HA. TEN HOVE 



PARATYPES 2, 4, & 6: BM(NH) 1992.173-174; 

 PARATYPE 3: USNM 130990). 2. Reef in front of Salinja 

 Fuik, buoy 13 of marine park, coral debris, 18-27 m, legit H. 

 A. ten Hove, 18. i. 1990 (4 specimens, ZMA V. Pol. 3874). 3. 

 Cornelisbaai, E, steep reef, coral debris, 18-26 m, legit H. 

 A. ten Hove, 17. i. 1990 (6 specimens, ZMA V. Pol. 3873). 4. 

 Piscaderabaai, outer bay W of entrance, sandy reef, coral 

 debris, legit H. A. ten Hove, 12. i. 1990 (5 specimens, ZMA 

 V. Pol.3872). 



Type locality. Curacao (Netherlands Antilles). 



Description. 



tubes: White to greyish-brown, occurring either individually 

 coiled upon themselves (Fig. 13, A), or in mutually bonded 

 aggregations of a few individuals (Fig. 13, B). They are 

 sub-circular in cross-section, with faint lateral ridges, and 

 bear fine smooth transverse ridges, and often have erect 

 anterior ends (Fig. 13, A,B). A fine opaque granular overlay 

 is present (Fig. 13, B), which can be seen under special 

 illumination only. Their external diameter attains 1.0 mm, 

 their erect portions somewhat smaller. The inside of one tube 

 has a light caramel coloured lining. 



ITS consist of a serrated ventral ridge along the concave 

 side of the tube (Fig. 13, C-E, H), which may not be well 

 developed and represented only by a few isolated or coa- 

 lesced teeth slanting backwards (Fig. 13, F), and a smooth 

 dorsal ridge on the convex side (Figs. 13, F,G; 3,K). The 

 latter is wedge-, T to Y-shaped in cross-section. In specimens 

 coiled upon themselves, the dorsal ridge occurs spirally on a 

 columella-shaped axis (Fig. 13, I). A short accessory latero- 

 dorsal ridge, which tapers anteriorly and posteriorly, may 

 also be present on either side (Fig. 13, F). Their edges are 

 unthickened. 



In life, the mid-ventral and mid-dorsal longitudinal grooves 

 of the abdomen are applied to the serrated ventral and 

 smooth dorsal ridges, respectively, of the tube (Fig. 13, G). 

 worms: Six specimens were taken out of their tubes. The 

 abdomen is complete in only one. Even though preserved in 

 alcohol, the abdominal segments still show clusters of pig- 

 mented specks laterally, light yellowish in one specimen, light 

 to bright orange in two, light to dark brown in two, and 

 uniformly caramel coloured in another. 



Five specimens have an operculum on one side and a 

 rudimentary operculum on the other; the branchial crown is 

 partly missing in the sixth. The length of the operculum and 

 peduncle varies from 1.0 mm in a juvenile paratype to 

 1.8 mm in the holotype. The operculum itself is 0.4—0.5 mm 

 long, 0.3-0.5 mm wide. It is zygomorph, attached to the 

 peduncle eccentrically, and bears numerous (up to 50) radii 

 (Fig. 13, K-M). The distal diameter of the peduncle is 1/3 to 

 2/3 that of the opercular base. The numbers of radioles on 

 both sides are 6/5, 5/4, 4/5, 4/4 and 4/3. They end in short 

 slender pinnule-free tips, which are about 1/5 to 1/7 the length 

 of the radioles (Fig. 13, K). The only complete specimen 

 (Fig. 13, J), is 4.9 mm long, with 42 abdominal segments, the 

 last 10 with capillaries. However, in another specimen, which 



is incomplete (Fig. 13, M), 76 abdominal segments could be 

 counted. 



Two clusters of prostomial ocelli are present. The num- 

 bers of thoracic chaetal tufts are 11/7, 9/9, 9/8, 8/8, 6.6. 

 Thoracic membranes extend to chaetigers 6/5, 4/4, 4/3, 4/?, 

 and they are damaged on both sides in the fifth. Two 

 groups of transparent to translucent ventral thoracic 

 glands, arranged in a V, and of unknown function, are 

 present. Further studies are needed to find out if they 

 could be responsible for secreting the caramel coloured 

 inner lining of the tube. 



Collar fascicles bear 2 or 3 fully formed bayonet chaetae 

 each, and a newly formed one deep within the bundle. Each 

 bayonet chaeta consists of a moderately long blade, a moder- 

 ately long unserrated notch which is 1/3 to 1/4 the length of 

 the blade, and 2-4, seldom 5, teeth on the basal boss (Fig. 13, 

 N-T). The teeth are comparatively larger as their number 

 decreases (Fig. 13, Q-T), and they may be accompanied by 

 one or two accessory teeth (Fig. 13, 0,P,S). Thoracic uncini 

 possess 5-7 teeth in a single row (Fig. 13, U). Abdominal 

 uncini are similar, with 5-6 teeth; anteriorly saw- and rasp- 

 shaped uncini may occur in a single row, posteriorly all uncini 

 are rasp-shaped. 



Live material. As observed in material collected in 1990, 

 radioles are faintly yellow to lemon, operculum is transpar- 

 ent, almost colourless. Thorax ventrally with 2-\ bright red to 

 orange globules arranged in a V, presumably thoracic glands; 

 body transparent with yellow tinge, brownish gut. 



Etymology. Named after Gayle Plaia who, when working 

 at the Florida Marine Research Institute, first observed ITS 

 in one of the species, S. ypsilon, from the Gulf of Mexico. 



Habitat and distribution. S. plaiae is a shallow water 

 species occurring in coral reefs, and has hitherto been col- 

 lected only from the type locality. 



Spiraserpula caribensis sp. nov. 



(Figs. 14, A-M; 15, A-Y; 16, A-K; 3, L; P1.4, E & F; 



P1.5,A-E) 



Material examined. 



Curasao (Neth. Ant.): 1. Awa Blancu, coral debris barrier, 

 20-30 cm, legit H.A. ten Hove, 15. ix. 1975, Stn. 75-38 

 (HOLOTYPE & 3 PARATYPES: ZMA V.Pol. 3715; 2 

 PARATYPES USNM 130987; 4 PARATYPES each: AM 

 W20157, NSMT, ZMK). 2. Awa Blancu, 3-4m, legit H. A. 

 ten Hove, 14.x. 1975, Stn. 75-37 (1 specimen, HUJ). 3. Awa 

 Blancu, coral debris, near Lagoen Blancu, 30-50 cm, legit 

 H. A. ten Hove, 30.vii.1970, Stn. 2090 (several subsamples 

 BM(NH) 1992.25-31, FSBC I 39195, ZMA V. Pol. 3716, 

 ZMB). 4. Lagoen Blancu, coral debris barrier, Halimeda, 

 20-30 cm, legit H. A. ten Hove, 15. ix. 1975, Stn. 75-36 (2 

 out of several specimens, RMNH 18174). 5. Awa di 

 Oostpunt, coral debris barrier, 30-50 cm, legit H. A. ten 

 Hove, 3.x. 1975, Stn. 75-77 (1 out of few specimens, 

 BM(NH) 1992.10-11. 6. St. Jorisbaai, Peninsula Groot St. 



Fig. 13 Spiraserpula plaiae sp. nov. A, Aggregation of tubes, showing fine transverse growth markings, granular overlay in places. B, 

 Juvenile tube. C-E, Fragments of tubes showing serrated ventral ridge (C & D, paratype 3), (E, paratype 2). F, Holotype showing variant 

 form of ventral ridge with isolated teeth, and ventro-lateral ridge. G-I, Paratype 4: G, posterior end of tube and worm. H, Portion of tube 

 showing ventral ridge. I, Dorsal ridge on columella-shaped axis. J-L, Two views of paratype 4, and its operculum: J, (Operculum not seen) 

 ventral longitudinal abdominal groove, and dorsal groove within 2nd coil; K, showing operculum; L, Another view of operculum. M, 

 Paratype 2. N & O, Bayonet chaetae from holotype. P-T, Bayonet chaetae from paratype. U, Thoracic uncini from holotype. 



