64 



T.G. PILLAI AND HA. TEN HOVE 



anic waters, at depths of up to 40 m on coral reefs. Hitherto 

 collected only from Bonaire, and Curasao, in the Caribbean. 



Spiraserpula singularis sp. no v. 



(Figs. 10, A-V; 3, B; P1.2, E & F) 



Material examined. 



Puerto Rico : 1. Isla Matei, near buoy of Marine Institute, 

 vertical reef with surge channels, no sand, from living corals, 

 29-33 m, legit H. A. ten Hove, 2.x. 1970, Stn. 2136A, 

 (HOLOTYPE & 3 PARATYPES, ZMAV.Pol.3710). 

 Curacao, (Neth. Ant.): 2. Salinja Fuik, reef in front, marine 

 park, 20-25 m, legit H. A. ten Hove, 18. i. 1990 (2 specimens 

 BM(NH) 1992.166-167). 3. Piscaderabaai, outer bay, W of 

 entrance, sandy reef, 20 m, from underside of coral debris, 

 not in sediment, legit H. A. ten Hove, 12. i. 1990 (3 speci- 

 mens, BM(NH) 1992.168-170). 



Type locality. Puerto Rico. 



Description. 



tubes: White, very tiny, one of the smallest species in the 

 genus. They may occur in mutually bonded aggregations of a 

 few individuals, or singly. Their coil diameters range from 

 1.2-1.3 mm. A granular overlay is present (Fig. 10, A,B), 

 which makes the external diameters of the tubes 

 (0.5-0.6 mm) considerably larger than their internal diam- 

 eters (0.2-0.25 mm). Their apertures bear small, somewhat 

 lobed, peristome-shaped extensions (Fig. 10, A,B), similar to 

 those found in S. massiliensis. 



ITS consist of a V-shaped dorsal ridge, actually an inverted 

 V, along the convex side of the first formed coil (Figs. 10, 

 C,D; 3, B). The two arms of the V are broader and outwardly 

 curved posteriorly, and their edges are smooth. Anteriorly 

 the dorsal ridge is a smooth plate only. A ventral ridge is 

 absent. When the worm is withdrawn into the tube, the 

 posterior, mid-dorsal part of the abdomen is applied to the 

 dorsal ridge. 



worms: Four specimens were taken out of their tubes 

 (Fig. 10, E-I). The holotype (Fig. 10, F), which is the largest, 

 is only 5.7 mm long, 0.2 mm wide in the thorax, and its 

 abdomen is 4.6 mm long. There are four pairs of radioles 

 which, including the short and slender pinnule-free tips 

 (Fig. 10, G), are about 0.55 mm long. There is a rudimentary 

 operculum on each side. Radioles are missing in the other 

 three specimens. However, a detached operculum was found 

 in the vial containing the specimens, and it is not certain 

 whether it belongs to one of them or another species. 



Two clusters of prostomial ocelli are present. Five or six 

 globular ventral thoracic glands are present, more or less 

 arranged in a V. The numbers of thoracic chaetigers on the 

 two sides in the four specimens are: 9/9, 9/8, 8/8, and 7/7. It 

 was not possible to establish the extent of the thoracic 

 membranes due to the extremely small size of the worms. An 

 apron is, however, absent. One paratype with an abdominal 

 length of 1.95 mm has 29 segments, with capillaries on the 

 last 5, and another 3.0 mm long with 39 segments, but the 

 capillaries cannot be seen, having probably been damaged. 



There are two bayonet chaetae in each collar fascicle. They 

 have moderately long serrated blades and 2-A teeth on the 

 basal boss and some accessory ones (Fig. 10, J, O-V; PI. 2, E). 

 The unserrated notch is 1/5 the length of the blade. Thoracic 

 uncini (Fig. 10, K,L) and anterior abdominal uncini (Fig. 10, 

 M,N) have 6 and 4-6 teeth, respectively, all in a single row. 

 The middle abdominal uncini are rasp-shaped (PI. 2, F), with 



up to 3 transverse rows of teeth above the single anterior 

 tooth. The abdominal segments bear 1 or 2 flat trumpet 

 chaetae in each bundle; one side is thickened into a claw- 

 shaped process (Fig. 10, N). 



Remarks. In the comparison with other Caribbean species, 

 S. singularis would key out mainly on the absence of a ventral 

 longitudinal ridge/row of teeth and probably also the absence 

 of an operculum. So far, the presence of an operculum has 

 been observed only in a doubtful field identification. The 

 form of thoracic glands, shape of dorsal ridge and collar 

 chaetae are similar to those in S. plaiae. 



Etymology, singularis (Latin) = unique; referring to the 

 unique ITS. 



Habitat and distribution. S. singularis sp. nov. appears 

 to be a shallow water coral reef dweller. It has hitherto been 

 collected only from Puerto Rico and Curacao. 



Spiraserpula karpatensis sp. nov. 



(Figs.ll, A-K;3,N) 



Material examined. 



Bonaire (Neth. Ant.): 1. Karpata, reef, 10 m, cryptic, legit H. 



A. ten Hove, 9.xi.l988 (HOLOTYPE, ZMA V.Pol.3712; 



PARATYPE, BM(NH) 1992.171). 



Curacao (Neth. Ant.): 2. Reef in front of Salinja Fuik, buoy 



13 of Marine Part, 20-30 m, corals and sandy/silty areas in 



equal amounts. From under side of coral debris, not in 



sediment, legit H. A. ten Hove, 18. i. 1990 (1 specimen, ZMA 



V. Pol. 3875). 



TYPE LOCALITY. Bonaire (Netherlands Antilles). 



Description. 



tubes: Pink, quite small, and lack longitudinal ridges. A pink 

 translucent granular overlay is present (Fig. 11, A). The tubes 

 of both the types are coiled upon themselves, one much more 

 than the others (Fig. 11, D). One has an erect part 2.0 mm 

 long, and a funnel-shaped, outwardly curved peristome 

 (Fig. 11, A), while the other has a somewhat thickened 

 anterior end (Fig. 11, D,E). The pink colouration gradually 

 fades to white towards the anterior end. The diameter of the 

 tubes is 0.6-0.7 mm in the attached parts, 0.4-0.6 mm in the 

 erect parts. 



ITS consist of a serrated ventral ridge and an unserrated 

 dorsal ridge, with a sharp edge in cross-section (Fig. 3, N). 

 The dorsal ridge may be absent (Fig. 11, B,C), or greatly 

 reduced (Fig. 11, D). In the latter it can be seen as a short 

 crescentic ridge through the broken end of one of the coils. 

 The serrated ventral ridge is regularly present (Fig. 11, B, C, 

 and bottom left of D). 



worms: The holotype is incomplete posteriorly (Fig. 11, F), 

 broken in three parts, with a total length of 4.3 mm. An 

 operculum and 4 radioles are present on the left side; the 

 radioles on the right are missing. The length of the radioles is 

 approximately 0.8 mm, with a pinnule-free tip of 0.1 mm. 

 The operculum (Fig. 11, G,H), is 0.26 mm long, and 0.28 mm 

 in diameter; inclusive of peduncle it is about 1 mm long. 

 Although bell-shaped, it is slightly zygomorphic, and has 

 numerous fine lobes, similar to that of S. plaiae described in 

 this paper. Branchial eyes have not been observed in the 

 fresh material. Two clusters of prostomial ocelli are present. 

 The thorax has 8 chaetigers on each side. The thoracic 

 membranes extend to the third chaetiger on the left (Fig. 11, 



