Tetrancistrum indicum (Paperna, 1972) 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 : 1523-1527

Tetrancistrum indicum (Paperna, 1972) comb. n.

( Figure 15 )

Synonym: Pseudohaliotrematoides polymorphus indicus Paperna, 1972 .

Measurements. Body 1229 (1057–1485; n 53) long; greatest width 498 (425–563; n 53) at body midlength. Haptor 109 (101–116; n 53) long, 83 (66–102; n 53) wide. Pharynx 59 (56–63; n 53) wide. Copulatory complex 102 (85–111; n 53) long. Dorsal anchor 79 (75– 82; n 53) long. Germarium 175 (130–218; n 53) long, 164 (123–193; n 53) wide; testis 203 (195–214; n 53) long, 235 (218–270; n 53) wide.

Type host and locality. Siganus sp.: Mombasa Coast , Indian Ocean (East Africa) .

Site of infestation. Gills. Specimens studied. Three voucher specimens from Siganus sutor, Indian Ocean , Mombasa, Kenya ( BMNH 1992-7-28 -90–92) .

Preυious records. Siganus sp.: Mombasa Coast, Indian Ocean (East Africa) as Pseudohaliotrematoides polymorphus indicus by Paperna (1972b). S. riυulatus: northern Gulf of Eilat, Israel as P. p. indicus by Diamant et al. (1999). S. sutor : Mombasa Coast, Kenya as Tetrancistrum sigani by Geets et al. (1997); Gazi Bay, 60 km south of Mombasa, Kenya as T. sigani by Geets et al. (1997) (unconfirmed); Nyali beach area, Kenya as T. sigani by Martens and Moens (1995) (unconfirmed).

Remarks. This species was originally described as Pseudohaliotrematoides polymorphus indica by Paperna (1972b). The helminth is elevated to specific rank and is transfered to Tetrancistrum as T. indicum comb. n. based on comparative morphology of the copulatory complex and haptoral armament (see Paperna 1972b).

Slide labels of the three available specimens of this species from the BMNH indicated that they were deposited in 1992 by Geets and Martens, who identified the parasites as T. sigani collected from S. sutor from the Indian Ocean, Mombasa, Kenya. The parasite specimens were insufficient for redescription of the species, but Geets et al. (1997) stated that the monogenoids they reported as T. sigani are smaller and the copulatory organ differs morphologically from that reported by Paperna (1972b) for T. indicum . Paperna (1972b) provided a measurement of 1690 Mm without a range for body size of T. indicum . However, maximum body sizes for present specimens of T. sigani (from S. fuscescens ), 1576 Mm, and those of specimens from S. sutor, 1485 Mm, do not appear to vary significantly from that originally reported by Paperna (1972b). Further, the primary difference in the morphology of the copulatory complex of that depicted by Paperna (1972b) and that shown by Geets and Martens’ specimens involves the terminal flare of the MCO, which in the original description of T. indicum is larger than that of the specimens from S. sutor ( Figure 15 ). This difference is likely a result of different methods used to mount the worms by respective investigators. In his many investigations of African monogenoids, Paperna generally used compressed specimens to describe the sclerotized parts, which could have resulted in distortion of the MCO, while the specimens deposited by Geets and Martens are mounted in resin under less compression. Thus, we tentatively consider the specimens from S. sutor to represent T. indicum . Confirmation of this identification, however, will depend on collection and description of new parasite material from the coast of eastern Africa.

Tetrancistrum polymorphum (Paperna, 1972) comb. n.

( Figures 16–21 )

Synonyms: Pseudohaliotrematoides polymorphus eilaticus Paperna, 1972 ; Pseudohaliotrematodides polymorphus eilaticus of Ktari and Ktari (1974) (lapsus).

Redescription. Based on 16 voucher specimens from S. luridus from Ras Mohammed National Park. Body foliiform; trunk broad; cephalic region and peduncle narrow, tapered. Greatest body width near body midlength. Cephalic lobes moderately developed; each head organ comprising several groupings of terminations of cephalic-gland ducts; large bilateral groups of cephalic glands posterolateral to pharynx, smaller bilateral groups anterolateral to pharynx. Eyespots absent; accumulations of minute subovate chromatic granules uncommon; isolated granules scattered throughout cephalic region. Pharynx ovate. Testis subspherical; vas deferens and seminal vesicle not observed; two prostatic reservoirs inconspicuous, looped dorsal to copulatory complex. Copulatory complex comprising MCO and accessory piece; MCO heavily sclerotized, tubular, C-shaped, with basal flange; accessory piece with subquadrate variably lobed base, submedial dorsal hump and tapered blunt tip. Germarium conical; ootype receiving vaginal duct and bilateral vitelline ducts; uterus extending to common genital pore along body midline; vaginal pore at level of copulatory complex; vaginal vestibule with anterior bulge at midlength, variable, lightly sclerotized; vaginal duct meandering; vitellarium dense. Haptoral hooks absent; filamentous hook loops infrequently retained in adult. Ventral and dorsal anchors typical; superficial root of ventral anchor noticeably longer than deep root. Ventral bar straight, with ends folded on to posterior margin of bar; dorsal bar with ends usually directed anteriorly.

Measurements. Body 1017 (770–1250; n 512) long; greatest width 290 (175–393; n 512). Haptor 94 (79–105; n 510) long, 83 (67–107; n 59) wide. Pharynx 55 (40–67; n 59) wide. Copulatory complex 82 (74–107; n 513) long. Ventral anchor 72 (67–76; n 58) long; base 37 (34–39; n 53) wide. Dorsal anchor 68 (60–73; n 512) long; base 26 (25–27; n 54) wide. Ventral bar 25 (22–32; n 58) long; dorsal bar 29 (25–34; n 58) long. Germarium 123 (79– 170; n 511) long, 106 (77–137; n 512) wide; testis 154 (110–210; n 512) long, 141 (96– 188; n 512) wide.

Source of current specimens. Siganus luridus: Nabq Bay, Ras Mohammed National Park (South Sinai, Red Sea), Egypt (28 ° 029520N, 34 ° 269210E), 9 September 2005, 23 October 2005.

Type host and locality. Siganus luridus : northwestern Gulf of Eilat (Taba and Coral Beach), Israel .

Site of infestation. Gills.

Specimens studied. Sixteen voucher specimens (USNPC 99364, 99365, MPM 18851, BMNH 2007.1.3.46–48, MSNM Pi 3912–3915).

Preυious records. Siganus luridus : northwestern Gulf of Eilat (Taba and Coral Beach), Israel as Pseudohaliotrematoides polymorphus eilaticus by Paperna (1972b); Gulf of Gabès, Tunisia as Pseudohaliotrematodides polymorphus eilaticus by Ktari and Ktari (1974); 8 km S of Eilat, Gulf of Eilat, Israel as Pseudohaliotrematoides p. eilaticus by Diamant and Paperna (1986); Mediterranean coast of Israel as P. p. eilaticus by Diamant and Paperna (1986); various localities in the Mediterranean Sea as Pseudohaliotrematoides polymorphus by Diamant (1989). S. riυulatus: northern Gulf of Eilat, Israel as P. p. eilaticus by Diamant et al. (1999).

Remarks. The original description of this species was developed by Paperna (1972b) for general delineation of three subspecies assigned to the specific taxon: Pseudohaliotrematoides polymorphus eilaticus , P. p. suezicus , and P. p. indicus. Of the three subspecies, Paperna (1972b) designated P. p. eilaticus as ‘‘syntype’’ for P. polymorphus . Because Pseudohaliotrematoides is considered a junior subjective synonym of Tetrancistrum and the three subspecies are elevated to specific rank, the epithet Tetrancistrum polymorphum is assigned to the form designated as syntype by Paperna (1972b).

Figures

Figure 15. Copulatory complex of Tetrancistrum indicum (Paperna, 1972) comb. n. from the shoemaker spinefoot, Siganus sutor, eastern coast of Africa (dorsal view).

Figures 16–21. Tetrancistrum polymorphum (Paperna, 1972) comb. n. from the dusky spinefoot, Siganus luridus, Ras Mohammed National Park, Egypt. (16) Whole mount (composite, ventral view). (17) Copulatory complex (dorsal view). (18) Dorsal bar. (19) Ventral anchor. (20) Ventral bar. (21) Dorsal anchor. Scale bar: 300 Mm (16); 30 Mm (17–21).