Euryhaliotrema thatcheri, Kritsky & Boeger, 2002

Kritsky, Delane C. & Boeger, Walter A., 2002, 41: New and previously described species of Dactylogyridae (Platyhelminthes) from the gills of marine and freshwater perciform fishes (Teleostei) with proposal of a new genus and a hypothesis on phylogeny, Zoosystema 24 (1), pp. 7-40 : 17-19

Euryhaliotrema thatcheri n. sp.

( Fig. 4 )

TYPE SPECIMENS. — Holotype ( INPA 407 ); 52 paratypes ( USNPC 91393 , 91394 , 91395 , 91396 , HWML 16426 , INPA 408 a-y, MNHN 23 HG Tg 149-152).

ETYMOLOGY. — This species is named for our friend and colleague, Dr Vernon Thatcher, retired, INPA, Manaus, Amazonas, Brazil, in recognition of his research on the parasites of fishes in the Neotropical Region.

TYPE HOST AND LOCALITY. — Gills of Plagioscion sp. (Sciaenidae) : Igarapé Zamula, Rio Negro near Barcelos, Amazonas, Brazil, 00°51’S, 62°46’W, 19.X.1996.

MATERIAL EXAMINED. — Plagioscion sp. (Sciaenidae) : 10 voucher specimens, Rio Paduairi (southern tributary), downstream from confluence of Rio Unini and Rio Negro above Novo Airão, Amazonas, Brazil, 02°20’S, 61°20’W, 4.X.1989 ( USNPC 91405); nine voucher specimens, Janauacá Lake near Manaus, Amazonas, Brazil, 03°25’S, 60°17’W, 20.IV.1979 ( USNPC 91407). Plagioscion squamosissimus (Sciaenidae) : five voucher specimens, Caicara de Orinoco Fish Market (Rio Orinoco), Bolivar, Venezuela, IV.1999 ( USNPC 91401); three voucher specimens, Puerto Ayacucho Fish Market (Rio Orinoco), Amazonas, Venezuela (according to vendor, the host was imported from Caicara de Orinoco, Bolivar, Venezuela), 24.III.1999 ( USNPC 91402); 13 voucher specimens, Belém Fish Market, Iquitos, Loreto, Peru, VII.1999 ( USNPC 91397, 91398, 91399, 91400); voucher specimen, Rio Nanay, Pampa Chica, 4.54 km west of Iquitos, Loreto, Peru, 03°45’09”S, 73°17’00”W, 7.VIII.1999 ( USNPC 91403); two voucher specimens, confluence of Rio Amazonas and Rio Tamshiyaca, about 3 km south of Tamshiyacu, Loreto, Peru, 04°01’42”S, 73°08’45”W, 28.VII.1999 ( USNPC 91404); voucher specimen, Manaus Fish Market, Manaus, Amazonas, Brazil, 13.IX.1978 ( USNPC 91406).

DESCRIPTION

Body 303 (233-360; n = 18) long, fusiform; greatest width 85 (65-115; n = 20) in posterior trunk at level of testis. Cephalic region broad; cephalic lobes poorly developed. Members of posterior pair of eyes larger, closer together than members of anterior pair; accessory granules uncommon in cephalic, anterior trunk regions. Pharynx spherical, 20 (15-22; n = 21) in diameter. Peduncle broad, tapered posteriorly; haptor subhexagonal, 66 (57-73; n = 19) wide, 51 (38- 69; n = 20) long. Ventral anchor 25 (24-26; n = 11) long, with poorly differentiated short roots, curved short shaft, point extending past level of tip of superficial root; base 13 (12-14; n = 9) wide. Dorsal anchor 22 (21-23; n = 15) long, with elongate superficial root usually bent around dorsal bar toward body midline ( Fig. 4H ), nonexistent deep root, straight shaft, point extending to level of tip of superficial root; base 15 (14-17; n = 15) wide. Bars similar, broadly U- or V-shaped, with posterior shield-like process originating from posterior margin; ventral bar 32 (31-40; n = 12) long, with delicate anteromedial muscle-attachment plate; dorsal bar 35 (33-39; n = 20) long. Hook 14 (13-15; n = 31) long, with uniform shank; FH loop about shank length. Copulatory organ a coil of about two and a half counterclockwise rings, 60 (53-68; n = 12) long, coil diameter 8 (7-9; n = 18). Accessory piece 16 (14-19; n = 7) long, comprising variable sheath along distal shaft of copulatory organ; articulation process absent. Testis 46 (31-63; n = 10) long, 26 (19-37; n = 10) wide, ovate; seminal vesicle pyriform; two prostatic reservoirs. Germarium subspherical to ovate, 37 (26-49; n = 11) long, 27 (20-38; n = 10) wide; oviduct, ootype not observed, uterus delicate, ventral; vaginal aperture marginal, distally funnel shaped; vaginal canal slightly arched anteriorly, sclerotized; seminal receptacle medial, pregermarial; vitellaria dense.

REMARKS

Euryhaliotrema thatcheri n. gen., n. sp. is sister group to E. monacanthus n. gen., n. sp. + E. lovejoyi n. gen., n. sp. based on presence of a short vaginal tube lacking a loop. It resembles E. lovejoyi n. gen., n. sp. by possessing a dorsal anchor/bar complex and in the morphology of the haptoral armament, while it compares to E. monacanthus n. gen., n. sp. in the morphology of the copulatory complex. It differs from both species in having a posterior flap on the ventral bar.

Figures

FIG. 4. — Euryhaliotrema thatcheri n. gen., n. sp.; A, whole mount (composite, ventral view); B, vagina (ventral view); C, copulatory complex (ventral view); D, ventral bar; E, dorsal bar; F, ventral anchor; G, hook; H, I, dorsal anchors. Scale bars: A, 100 µm; B-I, 25 µm.