Euryhaliotrema succedaneus, 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 : 21

Euryhaliotrema succedaneus n. sp.

( Fig. 6 )

TYPE SPECIMENS. — Holotype ( USNPC 91415); 13 paratypes ( USNPC 91416, 91417, 91418, 91419, 91420, HWML 16428, MNHN 25HG Tg 155-156). ETYMOLOGY. — From Latin succedaneus = a substitute, refers to the similarity of this species to the type species, E. chaoi n. gen., n. sp.

TYPE HOST AND LOCALITY. — Gills of Plagioscion squamosissimus (Sciaenidae) : Belém Fish Market, Iquitos, Loreto, Peru, VII.1999.

MATERIAL EXAMINED. — Plagioscion sp. (Sciaenidae) : Voucher specimen, 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 91421). Plagioscion squamosissimus (Sciaenidae) : Voucher specimen, Manaus Fish Market, Manaus, Amazonas, Brazil, 13.IX.1978 ( INPA 411).

DESCRIPTION

Body 873 (676-979; n = 8) long, fusiform; greatest width 170 (129-212; n = 8) usually near body midlength or in posterior trunk. Cephalic region narrow; cephalic lobes moderately developed. Members of posterior pair of eyes slightly larger, closer together than members of anterior pair; accessory granules scarce in cephalic region. Pharynx spherical, 42 (35-49; n = 9) in diameter. Peduncle moderate to narrow, gradually tapering posteriorly; haptor subhexagonal, 84 (78-93; n = 5) wide, 67 (59-81; n = 8) long. Anchors similar; each with poorly defined deep root, stocky superficial root, short shaft, point extending past level of tip of superficial root; ventral anchor 31 (29-34; n = 9) long, base 17 (14-18; n = 5) wide; dorsal anchor 30 (28-31; n = 5) long, base 15 (14-17; n = 3) wide. Ventral bar 30 (28-32; n = 6) long, yoke shaped, with narrow shield on posterior margin, delicate anteromedial muscleattachment plate; dorsal bar 32 (30-34; n = 5) long, broadly U-shaped, with small rounded shield on posteromedial margin. Hook 17 (16- 18; n = 8) long, shank uniform; FH loop about shank length. Copulatory organ meandering, 207 (200-213; n = 5) long. Accessory piece 26 (23- 28; n = 5) long, comprising variable sheath with distal loop enclosing tip of copulatory organ, lacking articulation process. Testis 143 (128-162; n = 6) long, 53 (47-62; n = 6) wide, elongate ovate; seminal vesicle fusiform; two prostatic reservoirs fusiform. Germarium bacilliform, 143 (123-174; n = 4) long, 51 (45-57; n = 4) wide, overlapping anterior end of testis; oviduct short; ootype not observed; uterus delicate, ventral. Vaginal aperture marginal, funnel shaped, with submarginal muscular-appearing bulb; vaginal canal with proximal coil prior to discharging into irregular medial seminal receptacle anterior to germarium. Vitellaria dense.

REMARKS

This species is sister to E. chaoi n. gen., n. sp., which it resembles in the general morphology of the copulatory complex and haptoral armament. Euryhaliotrema succedaneus n. gen., n. sp. differs from E. chaoi n. gen., n. sp. in having a shorter copulatory organ whose base lies anteri- or to the germarium and a shorter vaginal tube with one proximal loop before entering the seminal receptacle (numerous loops in E. chaoi n. gen., n. sp.).

Figures

FIG. 6. — Euryhaliotrema succedaneus n. gen., n. sp.; A, whole mount (composite, ventral view); B, vagina (ventral view); C, hook; D, ventral bar; E, dorsal bar; F, copulatory complex (ventral view); G, ventral anchor; H, dorsal anchor. Scale bars: A, 200 µm; B-H, 25 µm.