Tetrancistrum strophosolenus, Kritsky & Galli & Tingbao, 2007

Kritsky, Delane C., Galli, Paolo & Tingbao, Yang, 2007, Dactylogyrids (Monogenoidea) parasitizing the gills of spinefoots (Teleostei, Siganidae): revision of Tetrancistrum Goto and Kikuchi, 1917, with descriptions of two new species from Siganus spp. of the Red Sea and Celebes, Journal of Natural History 41 (25 - 28), pp. 1513-1551 : 1527-1529

Tetrancistrum strophosolenus sp. n.

( Figures 22–27 ) Synonyms: Pseudohaliotrematoides nagatyi Diamant, 1985 (nomen nudum); P. polymorphus

ssp. of Diamant and Paperna (1986); P. nagatyi of Diamant (1989) (nomen nudum); P.

polymorphus ‘‘nagatyi’’ of Diamant et al. (1999). Diamant (1989) reported that Paperna

(1972a) (paper not available to the present authors) referred to this species as

Tetrancistrum oraminii .

Description. Body foliiform; trunk broad; cephalic region narrow; peduncle tapered posteriorly; greatest body width at level of testis. Cephalic lobes moderately to well developed; each head organ comprises several groupings of terminations of cephalic-gland ducts; large bilateral groups of cephalic glands posterolateral to pharynx. Eyespots absent; accumulations of chromatic granules uncommon; minute subovate granules scattered throughout cephalic region. Pharynx ovate; intestinal caeca lack diverticula. Testis subspherical; vas deferens not observed; seminal vesicle simple, sigmoid; prostatic reservoirs inconspicuous, delicate tubes recurved dorsally to copulatory complex. Copulatory complex comprises unarticulated MCO and accessory piece. MCO flaskshaped, tapers to distal tube forming single counterclockwise ring ( Kritsky et al. 1985); proximal part of tube apparently fused with wall of basal flask. Accessory piece comprises two articulated parts near midlength; basal portion rod-shaped and with distal laminate portion folded dorsally. Germarium comparatively large, conical; ootype receives vaginal duct and bilateral vitelline ducts; uterus midventral, extends to common genital pore along body midline. Vaginal pore at level of copulatory complex; vaginal vestibule variable, lightly sclerotized; meandering vaginal duct extending to ootype. Vitellarium dense. Haptoral hooks absent. Ventral and dorsal anchors typical; superficial root of ventral anchor noticeably longer than deep root. Ventral bar straight, with ends folded posteriorly along posterior margin of bar; dorsal bar straight to slightly bowed, with terminal expansions.

Measurements. Body 1213 (949–1383; n 510) long; greatest width 292 (214–371; n 510). Haptor 117 (103–124; n 510) long, 85 (68–102; n 510) wide. Pharynx 50 (42–59; n 58) wide. Copulatory complex 79 (70–93; n 512) long. Ventral anchor 104 (101–108; n 52) long; base 50 (49–51; n 52) wide. Dorsal anchor 96 (94–98; n 52) long; base 30 (28–32; n 52) wide. Ventral bar 28 (27–29; n 52) long; dorsal bar 35 (34–36; n 52) long. Germarium 147 (122–169; n 58) long, 142 (108–163; n 58) wide; testis 221 (171–302; n 59) long, 165 (119–255; n 59) wide.

Type host and locality. Siganus riυulatus: Nabq Bay , Ras Mohammed National Park (South Sinai, Red Sea), Egypt (28 ° 029520N, 34 ° 269210E), 8 May 2003, 20 October 2005 .

Site of infestation. Gills.

Specimens studied. Holotype, USNPC 99366 ; 12 paratypes, USNPC 99367 , MPM 18850, BMNH 2007.1.3.44–45, MSNM Pi 3908–3911).

Other records. Siganus riυulatus: 8 km S of Eilat (Red Sea), Israel as Pseudohaliotrematoides polymorphus ssp. by Diamant and Paperna (1986); various localities in the Mediterranean Sea as P. nagatyi (nomen nudum) by Diamant (1989); northern Gulf of Eilat, Israel as P. polymorphus ‘‘nagatyi’’ by Diamant et al. (1999); Mediterranean coast of Israel as P. polymorphus ‘‘nagatyi’’ by Diamant et al. (1999).

Etymology. The specific name is from Greek (strophos 5twisted+ solenos 5a pipe) and refers to the morphology of the copulatory complex.

Remarks. Tetrancistrum strophosolenus sp. n. differs from all congeners by possessing a vaselike base of the MCO from which a narrow distal coiled tube arises. The species was originally described in an unpublished portion of a thesis ( Diamant 1985) as Pseudohaliotrematoides nagati (a nomen nudum). References to the species have been frequently made in the literature under different combinations of names by Diamant and co-workers, but in none of these accounts were the names suggested to be available sensu the International Code of Zoological Nomenclature. We have confirmed that specimens described in the thesis are conspecific with T. strophosolenus through copies of the original drawings from the thesis provided by Dr A. Diamant, who graciously allowed us to describe the new species.

Figures

Figures 22–27. Tetrancistrum strophosolenus sp. n. from the marbled spinefoot, Siganus riυulatus, Ras Mohammed National Park, Egypt. (22) Whole mount (composite, ventral view). (23) Dorsal anchor. (24) Ventral anchor. (25) Dorsal bar. (26) Ventral bar. (27) Copulatory complex (ventral view). Scale bar: 300 Mm (22); 30 Mm (23–27).