Pseudohaliotrema falcata, Lim, 2010

Lim, L. H. S., 2010, Three new species of Pseudohaliotrema Yamaguti, 1953 (Monogenea: Ancyrocephalidae) from Siganus species (Siganidae) and the description of a mechanism for cross-insemination, Journal of Natural History 36 (14), pp. 1639-1660 : 1650

Pseudohaliotrema falcata n. sp.

(gures 2c, 4–6)

Description

Comparatively large worms, with broad body proper, 1172 (1008–1300) Ö 285 (268–294); narrow cephalic region; three pairs of head organs; four eye-spots consisting of scattered pigment (in xed specimens); comparatively shorter peduncle, 112 (84–143) Ö 125 (117–134), demarcating body from haptor. Intestinal caeca con uent just anterior to peduncle. Haptor broader than long, 92 (84–109) Ö 128 (117–143); dorsal anchors with well-developed roots, inner length 43 (42–44), outer length 34 (32–36), inner root 22 (20–24), outer roots 9 (8–10), point 6 (4–10); ventral anchors robust with expanded outer roots, inner length 32 (30–34), outer length 31 (30–34), inner root 14 (14–16), outer root 8 (6–10), point 5 (4–6); dorsal connecting bar stout, broad, V-shaped, 9 (8–10) Ö 34 (32–36); ventral connecting bar V-shaped, 4 (3–5) Ö 36 (35–38); 14 marginal hooks of larval type, length 11 (10–12). Testis round to ovoid, lateral to ovary; vas deferens leaves left margin of testis antero-ventrally, passing anteriorly intercaecally, to level of male organ, distending forming seminal vesicle; descending, narrowing as ejaculatory duct, turning anteriorly, entering male organ. Male organ consisting of two sclerotized parts: large curved sclerotized piece with scythe-like ending (ap 1 in gure 1f) with broad rather obscure opening (indicated by arrow in gure 1f) through which ejaculatory duct and duct from prostatic reservoir enter; second sclerotized piece with club-like ending (ap 2 in gure 1f) and large proximal opening. Spermatophor e size roughly estimated to be 220 (200–250) Ö 180 (150–200) but shape diYcult to ascertain due to distortion, stored in chamber with ventral opening, antero-ventral to male organ. Prostatic glands postero-lateral (on both sides) of pharyngeal region; left and right prostatic ducts unite to form common duct, draining into large prostatic reservoir. Ovary elongate; oviduct leaves anterior part of ovary; oötype receiving ducts from Mehlis’ gland and seminal receptacle; uterus ascends mid-ventrally; uterine pore opens ventrally, near male organ. Dextro-lateral vaginal pouch housing eversible spermatophore transfer tube; vaginal duct linking to seminal receptacle. Vitelline system co-extensive with intestinal caeca; lateral elds unite posterior to intestinal caeca.

Type-host. Siganus guttatus (Bloch) .

Type-locality. OV Singapore.

No. of specimens measured. Twenty.