72 



T.G. PILLAI AND H.A. TEN HOVE 



Table 13 5. caribensis sp. nov. A summary of data from four 

 samples from Curacao (Stns. 75-38, 75-36 and 75-77 and 2096). 



No. of specimens (n=10) 

 No of radioles per side 



No. of specimens (n = 14) 

 No. of thoracic chaetal tufts 



No. of specimens (n = 10) 

 Thoracic membrane ends 



2 7 1 

 6/5 5/5 5/4 



2 13 3 4 1 



9/8 9/7 8/8 8/7 7/7 7/6 



12 4 2 1 



5/4 5/3 4/4 4/3 3/3 



Table 14 5. caribensis sp. nov. A summary of data from the 

 Florida material. 



No of specimens (n=ll) 

 No of radioles per side 



No. of specim.(n=29) 

 No. of trior, chaet. 



No. of specimens (n=26) 

 Thor. membranes end on 



2 

 6/6 



5 

 5/5 



4 



4/4 



18 13 6 12 2 4 1 



10/6 9/8 9/7 8/8 8/7 8/6 7/7 7/6 7/5 6/6 



3 3 4 9 7 



5/4 5/3 4/4 4/3 3/3 



unpublished research of M. van Vliet and R. Fijn (see 

 acknowledgements) . 



The blades of developing bayonet chaetae deep within the 

 fascicle are similar to the fully formed dagger-shaped bayonet 

 chaetae, indicating that the latter have not resulted from wear 

 and tear of bayonets with tapered tips. Occasionally, a 

 developing chaeta with a truncated blade and tapered tip 

 (Fig. 15, F,S), occurs deep within a fascicle, which provides a 

 clue to the origin of the former. Reduction in length of the 

 blade together with extension of the unserrated notch has 

 resulted in stout, truncated bayonet chaetae, with smooth 

 and dagger-shaped blades. 



Thoracic uncini (Fig. 15, J) usually possess 6 teeth, and 

 anterior abdominal uncini (Fig. 15, K,X) 4 or 5, in a single 

 row. Posterior abdominal uncini are rasp-shaped (P1.5, A). 

 Flat trumpet chaetae number up to about 5 in each bundle, 

 and their triangular distal ends bear a hook-shaped process 

 on one side, and the other side is drawn out into an acute 

 angle (Fig. 15, L-N, Y; P1.5, B). 



Collections from other localities. The specimens from 

 the other localities listed above agree with those from the 

 type locality. However, the smaller size of the tube and 

 chaetae of the specimens from Gatun Locks, Panama, and 

 the highly branched tubes of the specimens from Grenada, 

 are worth noting. 



Live material. As observed in material from Curacao, 

 radioles are colourless, transparent to transparently orange, 

 sometimes with reddish pinnules. Base of branchial lobes and 

 the collar may be tinged with purple. Branchial eyes not 



present. Body predominantly transparent orange, thorax 

 ventrally reddish. 



Etymology. The name acknowledges the fact that this 

 appears to be the most widely distributed species of Spiraser- 

 pula in the Caribbean. 



Habitat and distribution. S. caribensis inhabits shallow 

 water, intertidally down to a few metres in the Caribbean, to 

 18 m in the E. Gulf of Mexico (temperature submerged ?). It 

 occurs in a variety of habitats, from rockpools to the under- 

 sides of boulders in mangrove glades. It is able to survive well 

 in somewhat muddy environments, always, however, cryptic 

 between piles of rock or similar hard substrata. 



It appears to be widely distributed in the Caribbean and 

 Gulf of Mexico, from Florida to Barbuda and Panama. 



A population from Grenada, with frequently branching 

 tubes and which is, for the present, regarded as belonging to 

 5. caribensis, is described below (Fig. 16, A-K): 



Material examined. 



Grenada (Caribbean), Hog Island, near Pt. Salines, 0-1.5 m, 

 Rhizophora, mud, legit P. Wagenaar Hummelinck, 

 8.vii.l967, Stn. 1550 (5 specimens and 4 tubes, ZMA V.Pol. 

 3706, USNM 130985, BM(NH) 1992.32). 



Description. 



tubes: Dark pink to rose coloured. Except for their posterior 

 ends, they are all uncoiled, conspicuously branched, and 

 attached to the substratum throughout (Fig. 16, A). A granu- 

 lar overlay is present, larger granules constituting a median 

 longitudinal ridge and a pair of lateral ridges (Fig. 16, A,B). 

 The colouration is darker pink between the median and 

 lateral ridges. Fine transverse ridges may be present in 

 places. The lumen of the tube is continuous with that of the 

 branches. 



ITS are similar to those of S. caribensis. However, the 

 tongue-shaped cross-section of the dorsal ridge is somewhat 

 more pronounced. 



worms: Three worms were taken out of the tubes, of which 

 the longest (Fig. 16, C,D), has a total length of 9.2 mm. There 

 are up to 5 pairs of radioles and a rudimentary operculum on 

 each side. The radioles are up to about 2.0 mm long, 1/6-1/8 

 of which constitute pinnule-free tips. Measurements and 

 meristic data are given in Table 15: 



Two clusters of prostomial ocelli are present. All three 

 specimens bear 7 thoracic chaetal tufts on the left and 6 on 

 the right. The thoracic membranes end on the third thoracic 

 chaetiger on both sides in the first specimen, but are damaged 

 in the others. A pair of ventral thoracic glands is present 

 (Fig.l6,C). 



Each bayonet chaeta typically consists of a short, serrated 

 blade, and an unserrated notch and a tapered tip (Fig. 16, 

 E-K). There are 2 or 3 large teeth on the basal boss, and a 

 few accessory teeth. Older chaetae in a fascicle which have 



Fig. 15 Spiraserpula caribensis sp. nov. A-E & J-N, From Curacao, St. Jorisbaai, Stn. 2096. F-I, from Curacao, Lagoen Blancu, Stn. 75-36. 

 O-Y, From Panama, Gatun Locks: (O-S, from Stn. 81.1; T-Y, from Stn. 81.2). A, Tubes showing granular overlay, external ridges and 

 transverse wrinkles. B-E, Bayonet chaetae from the same fascicle with short dagger-shaped blades. F-I, Bayonet chaetae from fascicle of 

 another specimen: F, Newly formed, deep within fascicle; G-I, Older chaetae. J, Thoracic uncini. K, Anterior abdominal uncini, and L, 

 flat trumpet chaetae, from same segment. M & N, Flat abdominal trumpet chaetae from other specimens. O & P, Tube opened 

 substratally, viewed from two different angles, with worm in situ showing thoracic glands; O, with dorsal ridge only, and P, with both dorsal 

 and ventral ridges. Q-S and T-W, Bayonets from two different fascicles. Note much smaller size compared with those of Florida (Fig. 14, 

 K-L) and Curasao (Fig. 15, B-I) material', although drawn under same magnification. X & Y, Anterior abdominal uncini and flat trumpet 

 chaetae from same segment. Note much smaller size than in Curasao material (Fig. 15, L-N). • 



