Pseudohaliotrema virgata, 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 : 1646-1648

Pseudohaliotrema virgata n. sp.

(gures 1, 2a)

Description

Small monogenean, 331 (244–365) Ö 72 (48–86); narrow cephalic region with three sets of head organs, four eye-spots with scattered pigment (in xed specimens), intestinal caeca unite just anterior to peduncle. Peduncle, 29 (28–43) Ö 34 (24–38), demarcating haptor from body proper. Haptor, 34 (33–35) Ö 48 (46–49); dorsal anchors with developed roots: inner length 29 (28–30), outer length 22 (20–23), Three new species of Pseudohaliotrema 1647 inner root 13 (12–14), outer root 4 (3–4), point 6 (5–6); ventral anchors with slightly expanded outer root: inner length 21 (20–22), outer length 20 (18–20), inner root 9 (8–10), outer root 5 (4–6), point 5 (4–6); dorsal connecting bar V-shaped, 5(4–6) Ö 16 (16–19); ventral bar almost rod-shaped, 5(4–5) Ö 14 (14–15); 14 marginal hooks of larval type, 8 (8–9). Testis ovoid, sinistral, lateral to ovary; vas deferens leaves left anterior margin of testis, intercaecal, passing anteriorly to male organ, distending to form seminal vesicle; descending, narrowing as ejaculatory duct, turning anteriorly to proximal part of male organ. Male organ consisting of two sclerotized parts, one part is sclerotized club-like piece (ap 1 in gure 1f) with obscure proximal opening (indicated by arrow in gure 1f) through which ejaculatory duct and duct from prostatic reservoir enter; other is truncated sclerotized piece (ap 2 in gure 1f) with large proximal opening. Spermatophore oval, 61 (53–67) Ö 40 (31–48), with short stalk 11 (10–12) Ö 10 (8–11), stored in spermatophor e chamber, located anterior to male organ, ventral opening. Left and right prostatic glands postero-lateral to pharynx, antero-lateral to male organ; left and right prostatic ducts join to form common duct opening into sausage-shaped prostatic reservoir. Ovary dextral; oviduct leaves anterior part of ovary to form oötype, receiving ducts from Mehlis’ gland and seminal receptacle. Uterus ascends mid-ventrally, opening near male organ. Vaginal pouch dextro-lateral, associated with eversible spermatophore transfer tube; sclerotized vaginal duct connected to seminal receptacle. Vitelline system follicular, co-extensive with intestinal caeca; lateral elds con uent posterior to intestinal caeca just anterior to peduncle.

Type-host. Siganus virgatus (Valenciennes, 1835) .

Type-locality. OV Singapore.

No. of specimens measured. Twenty.

Type-specimens. HOLOTYPE ( BM (NH) No. 2001.4.30 .1) and PARATYPES ( BM (NH) Nos 2001.4.30 .2 and 2001.4.30.3 –5) in The Natural History Museum, London. Other paratypes in the author’s collection .

Etymology. This species is named after the host species.

1648 L. H. S. Lim

Comments

This species possesses characteristics of Pseudohaliotrema (sensu stricto) in having a modi ed sclerotized copulatory organ (male organ), a modi ed eversible tube associated with the vaginal system (spermatophore transfer tube), spermatophores and well-demarcated peduncle. The male organ of this new species is similar to those of P. sigani and P. sphincteroporus , although they diVer in detail. In P. sigani the sclerotized piece of one part of the male organ is slender and long with a club-like ending: in the present species the corresponding piece is truncated (see gure 1f, ap2), while in the larger P. sphincteroporus the ending is bi d. Pseudohaliotrema sphincteroporus is also unique in having a distinct, prominent genital pore which is not found in P. sigani or the present species. Of the species of Pseudohaliotrema (sensu stricto), this species is similar to P. sigani in body size (gure 2a, d), but the two diVer in the shape and size of the bars, which are more slender in the former.

Various stages of spermatophore exchange between diVerent individuals of P. virgata n. sp. were observed and will be discussed below.