Euryhaliotrema chaoi Kritsky & Boeger 2002, n. sp.
Creators: name: Kritsky, Delane C.
name: Boeger, Walter A.
Publisher: name: Zenodo
Year: 2002
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Monogenea
Dactylogyridea
Ancyrocephalidae
Euryhaliotrema
Euryhaliotrema chaoi

description: Euryhaliotrema chaoi n. sp.   
(Fig. 1)  
 TYPE SPECIMENS. — Holotype (INPA 401); 23 paratypes (INPA 402 a-k, USNPC 91369, 91370, 91371, HWML 16423, MNHN 21 HG Tg 143-144). ETYMOLOGY. — This species is named for Dr L. N. Chao, INPA, Manaus, Amazonas, Brazil, who provided specimens of Plagioscion sp. and in recognition of his research on sciaenid and other Neotropical fishes.   
 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): 12 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 91374). Plagioscion squamosissimus (Sciaenidae): seven voucher specimens, Manaus Fish Market, Manaus, Amazonas, Brazil, 13.IX.1978 (USNPC 91372); four voucher specimens, Belém Fish Market, Iquitos, Loreto, Peru, VII.1999 (USNPC 91375, 91376); 2 voucher specimens, Rio Nanay, Pampa Chica, 4.54 km west of Iquitos, Loreto, Peru, 03°45’09”S, 73°17’00”W, 7.VIII.1999 (USNPC 91373).   
DESCRIPTION  
Body 706 (614-799; n = 10) long, fusiform; greatest width 142 (121-171; n = 10) usually at level of testis. Cephalic region broad; cephalic lobes moderately developed. Members of posterior pair of eyes slightly larger, closer together than members of anterior pair; accessory granules in cephalic, anterior trunk regions. Pharynx spherical, 38 (34-45; n = 10) in diameter. Peduncle broad, tapered posteriorly; haptor subhexagonal, 82 (75-87; n = 10) wide, 67 (55- 78; n = 10) long. Anchors similar; each with poorly differentiated short roots, evenly curved to straight short shaft, point extending past level of tip of superficial root; superficial root of dorsal anchor frequently bent around tips of dorsal bar toward body midline (Fig. 1I); ventral anchor 32 (31-33; n = 9) long, base 17 (16-19; n = 8) wide; dorsal anchor 30 (28-31; n = 8) long, base 15 (14-18; n = 7) wide. Ventral bar 33 (32-35; n = 8) long, yoke shaped, with thin short shield on posterior margin, delicate anteromedial muscle-attachment plate; dorsal bar 39 (35-40; n = 8) long, broadly U-shaped, ends bent laterally, with small rounded shield on posteromedial margin. Hook 15 (14-16; n = 27) long, shank varying slightly in width along length; filamentous hooklet (FH) loop about shank length. Copulatory organ meandering, 279 (220-344; n = 8) long; base lying dorsal to germarium. Accessory piece 28 (26-32; n = 7) long, comprising variable sheath with subterminal branch, lacking articulation process. Testis 105 (78-153; n = 7) long, 56 (45-74; n = 6) wide, ovate; seminal vesicle lying dorsal to germarium, pyriform; two prostatic reservoirs, one elongate pyriform, one subpyramidal, both dorsal to germarium. Germarium subovate, 64 (46-90; n = 8) long, 43 (30-51; n = 8) wide, slightly overlapping testis; oviduct, ootype not observed; uterus delicate, ventral. Vaginal aperture marginal; vagina distally funnel shaped, proximal portion an elongate narrow sclerotized tube coiled prior to discharging into large medial seminal receptacle. Vitellaria dense.  
REMARKS  
 Euryhaliotrema chaoi n. gen., n. sp. is the type species of the genus. It differs from its congenitors in possessing an elongate meandering copulatory organ with its base lying dorsal to the germarium.
description: Published as part of 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, pp. 7-40 in Zoosystema 24 (1) on pages 11-13, DOI: 10.5281/zenodo.5399742