Tetrancistrum oraminii Young, 1967

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 : 1534-1536

Tetrancistrum oraminii Young, 1967

( Figures 41–45 )

Measurements. Body 1204 (1181–1236; n 53) long; greatest width 335 (301–384; n 55) near midlength or in anterior trunk. Haptor 110 (103–117; n 52) long, 119 (110–131; n 53) wide. Pharynx 56 (52–61; n 55) wide. Copulatory complex 108 (104–111; n 55) long. Ventral anchor 88 (83–94; n 55) long; base 33 (28–36; n 54) wide. Dorsal anchor 88 (84–90; n 55) long; base 24 (22–27; n 53) wide. Ventral bar 26 (25–28; n 55) long; dorsal

bar 34 (31–36; n 54) long. Germarium 108 (97–121; n 54) long, 139 (130–159; n 54) wide; testis 156 (130–184; n 55) long, 148 (128–177; n 55) wide.

Type host and locality. Siganus canaliculatus: Heron Island , Queensland, Australia .

Site of infestation. Gills.

Specimens studied. Holotype ( USNPC 60872 ); four paratypes ( USNPC 60873 ).

Preυious records. Siganus canaliculatus: Heron Island, Queensland, Australia ( Young 1967). S. fuscescens: Heron Island, Great Barrier Reef, Australia ( Lester and Sewell 1989).

Remarks. The original description by Young (1967) of T. oraminii is adequate. Present respective measurements correspond to those in the original description, but Young (1967) did not provide the dimensions of the gonads, haptor, and pharynx. The morphology of the intestinal caeca, described by Young (1967) as lacking lateral diverticula and connected by a transverse ‘‘crus’’ posterior to the testis, could not be verified in the type specimens; the stain (haemalum) apparently had faded through time. Young (1967) recorded the host of T. oraminii as S. oramin , but this species is currently considered a junior synonym of S. canaliculatus by Woodland (1990) and Froese and Pauly (2006).

Tetrancistrum aealtairense nom. n.

Synonym: Tetrancistrum indicum Raju and Rao, 1978 .

Type host and locality. Siganus canaliculatus: Waltair Coast , Bay of Bengal, India .

Site of infestation. Gills.

Preυious record. No other records except for the original description by Raju and Rao (1978).

Etymology. The specific name refers to the region of India from which the species was originally described.

Remarks. Specimens of this species were not available for study and the type specimens have apparently not survived. This species was originally described by Raju and Rao (1978) as T. indicum from the gills of Siganus oramin (now S. canaliculatus ) from the Waltair Coast of India. While it clearly belongs to Tetrancistrum , the validity of this species is problematical, and the drawings provided by the original authors, particularly those of the copulatory complex and haptoral structures, are insufficient for specific diagnosis. Meaurements of the anchors reported by Raju and Rao (1978) and their Figure 4b of the MCO and accessory piece suggest that this species may be a junior synonym of T. oraminii reported from the same host in Australia. In their original figure, the MCO is depicted as a sigmoid tube with a long proximal flange, and the accessory piece, while comparatively smaller, has the general shape of that of T. oraminii . However, Raju and Rao (1978) describe the dorsal bar as being ‘‘slender and recuved (sic)’’, which does not correspond to that of T. oraminii . Therefore, we do not at this time consider the species a synonym of T. oraminii but consider it a species inquirenda.

With the transfer of Pseudohaliotrematoides polymorphus indica Paperna, 1972 , to Tetrancistrum as T. indicum comb. n., Raju and Rao’s specific name for the species becomes a junior homonym and must be replaced. Thus, T. aealtairense nom. n. is proposed for the species.

Tetrancistrum species from non-siganid hosts

Figures

Figures 41–45. Copulatory and haptoral sclerites of Tetrancistsrum oraminii Young, 1967 from the white-spotted spinefoot, Siganus canaliculatus, Great Barrier Reef, Australia. (41) Copulatory complex (ventral view). (42) Ventral anchor. (43) Dorsal anchor. (44) Ventral bar. (45) Dorsal bar. Scale bar: 30 Mm.

Figures 1–7. Tetrancistrum sigani Goto and Kikuchi, 1917 from the mottled spinefoot, Siganus fuscescens, Great Barrier Reef, Australia. (1) Whole mount (composite, ventral view). (2) Copulatory complex (ventral view, slightly compressed). (3) Copulatory complex (ventral view). (4) Ventral bar. (5) Dorsal bar. (6) Ventral anchor. (7) Dorsal anchor. Scale bar: 400 Mm (1); 30 Mm (2–7).