Affecauda rugosa n. sp. (Fig. 1)

Type­host: Zebrasoma veliferum (Bloch, 1797), Acanthuridae; sailfin tang.

Site: intestine.

Type­locality: Noumea, New Caledonia (21°30'S 165°30'E, 22 Nov. 1997).

Prevalence: 2 of 3 (66.7%).

Intensity: 0.66.

Deposition of specimens: holotype QM G222106.

Etymology: This species is named from the Latin rugosus (= wrinkled) and refers to the presence of tegumental annulations along most of the body, which gives the appearance of wrinkles.

Description: Based on 2 whole­mount preparations of 1 mature, complete worm and 1 immature, fractured worm. Measurements in Table 1. Body elongate, extremely slender for entire length, rounded at ends, pronounced curvature dorsoventrally (Figure 1); pale creamy­yellow in life. Tegument distinctly annulated from level of oesophagus to immediately anterior to ventral sucker. Ventral sucker longitudinally elongate, at posterior extremity of body; peduncle inconspicuous. Pharynx elongate, barrel­shaped, subterminal, surrounds mouth. Oesophagus long, sigmoid, with single loop, posterior chamber developed, invested with glands along entire length; lining thick. Oesophageal bulb smaller than pharynx, ovoid, discrete. Caeca of equal lengths, terminate posterior to level of genital aperture.

A. rugosa A. salacia

n = 1 n = 4

Feature Measurement Mean Min Max body length 1456 1504 1456 1536 ratio of oesophageal bulb to ventral sucker (length) 0.28 0.64 0.67 0.60 ratio of oesophagus to body (length) 0.28 0.50 0.51 0.49 ratio of caeca to body (length) 0.26 0.16 0.15 0.17

Testes 2, entire, ovoid, tandem, contiguous, in posterior third of body. Vasa efferentia not observed. Cirrus­sac present, spherical, ventral to caeca, encased in muscular capsule contiguous with pars prostatica and anterior portion of seminal vesicle. Seminal vesicle external, unipartite, frequently obscured by uterus. Pars prostatica large, cylindrical, tapering anteriorly, thickly surrounded by prostate gland cells, which partially penetrate cirrus­sac. Ejaculatory duct short, simple, expanding distally; everted cirrus not observed. Genital atrium large, convoluted. Genital pore irregularly elliptical, median, ventral to caeca.

Ovary ovoid, pretesticular, sinistral, overlapping anterior testis; oviduct associated with swollen insemination chamber. Seminal receptacle canalicular, globular, dorsal to ovary. Ootype anterior to ovary. Mehlis’ gland not observed. Laurer’s canal proceeds posterodorsally, opening dorsal to ovary. Vitellarium follicular; follicles largely restricted to anterior half of body, extend from posterior margin of pharynx to anterior margin of ovary; dorsal, ventral and lateral fields confluent. Vitelline reservoir globular, posterior to ovary. Uterus entirely pre­ovarian. Eggs unembryonated in utero; opercula not observed. Opening of uterus unspecialised, enters genital atrium sinistral to cirrus­sac.

Excretory vesicle saccular; lining not observed; pore opens on small, but distinct dorsosubterminal papilla. Primary collecting ducts arise anterolaterally; 1 pair only. Lymphatic system not observed.

Comments: Affecauda rugosa is immediately distinguished from the type­species, A. annulata, by the difference in the posterior body shape. Specimens of A. annulata have a distinctively elongate, extremely narrow body posterior to the gonads, at the terminus of which is the ventral sucker; this condition is not seen in A. rugosa . Further, the annulations on the tegument of A. rugosa are more extensive than those of A. annulata, commencing immediately posterior to the level of the pharynx and terminating immediately anterior to the ventral sucker on the ventral surface and immediately anterior to the excretory pore on the dorsum. The seminal vesicle of A. rugosa is unipartite, rather than bipartite, and the ovary is pretesticular and sinistral to the midline, in contrast to the intertesticular position in A. annulata . This combination of morphological features makes A. rugosa clearly distinct from A. annulata .

Although only 1 mature specimen of this species has been recovered, the condition of this specimen is excellent and it is gravid. The morphology of this specimen is clearly different from that of A. annulata, and accordingly we believe that this new species description is justified. The collection of additional material for incorporation into this description is highly desirable, as is the fixation of material in ethanol for use in DNAbased studies.