Treptodemus latus MANTER, 1961

Sey, O., Nahhas, F. M., Uch, S. & Vang, C., 2003, Digenetic Trematodes From Marine Fishes Off The Coast Of Kuwait, Arabian Gulf: Fellodistomidae And Some Smaller Families, New Host And Geographic Records, Acta Zoologica Academiae Scientiarum Hungaricae 49 (3), pp. 179-200 : 192-193

Treptodemus latus MANTER, 1961

( Fig. 5 )

Host: Hemiramphus marginatus (FORSSKÅL, 1775) Hemiramphidae (new host and geographic record)

Description based on 29 specimens, measurements on 18. Body 200–600 x 780–1,600 (430 × 1,235); ratio of length to width 1: 2.1–3.00 (1:2.62). Tegument aspinose; eyespot pigment small, diffuse, not evident in some. Oral and ventral suckers absent. Mouth small opening at mid anterior edge; prepharynx 0–15 (5) long; pharynx 45–73 × 28–55 (59 × 44); oesophagus 20–105 (43); caeca extending laterally, arching around reproductive structures and excretory canals, ending blindly, near posterior end of body. Testis single, oval, 120–260 x 180–340 (205 × 258) in mid left half of body. Cirrus sac spherical to oval, 150–230 × 170–290 (194–259), in middle of right half of body; seminal vesicle internal, occupying one half to two thirds of cirrus sac; pars prostatica not evident; cirrus thick-walled relatively short. Ovary spherical to oval, 70–130 × 90–138 (107 × 129), median to submedian, immediately posterior to intestinal bifurcation; seminal receptacle spherical to oval, 100–130 × 130–220, postovarian, near midbody; Mehlis’ gland and ootype submedian, closer to cirrus sac in some; uterus extending to left side anterior to testis, then turning dorsally to right side; metraterm thick-walled, anterior to cirrus sac, entering genital atrium from left side; seminal receptacle 55–98 × 80–103, just posterior to Mehlis’gland. Vitelline follicles irregular in shape, circumcaecal, confluent at oesophageal level. Genital atrium large, pore slightly dextral and anterior to midbody, surrounded by muscular sphincter with radiating fibers. Eggs 68–83 × 25–45 (72 × 35) non-embryonated, often collapsed. Excretory system consisting of 2 wide canals, extending anteriorly to near level of seminal receptacle then laterally, one to about midlevel of testis, the other to midlevel of cirrus sac, and connecting posteriorly with thin short tube to terminal excretory pore.

Remarks. MANTER (1961) described this species from a single specimen recovered from “a half beak, probably Hemiramphus sp. ” ( Hemiramphidae ) from Fiji. He assigned it to the family Bivesiculidae based on absence of suckers, single testis, 2 vasa efferentia, and 2 excretory vesicles. YAMAGUTI (1971) erected the family Treptodemidae to accommodate this monotypic genus, but CRIBB (2002) retained it in the family Bivesiculidae . MANTER’ s description is remarkably accurate. Wehavefollowed M ANTER’ s descriptions on every specimen and found that collectively the details agree with his. Differences we observed are the somewhat narrower eggs and vitelline follicles that are confluent at the oesophageal level. In several specimens, the intestinal contents consist of a black pigment suggestive of digested hemoglobin (?). Treptodemus latus was also reported and briefly described by MACHIDA and KURAMOCHI (2000) from Hemiramphus far from Okinawa, Japan and Mactan, Philippines. The differences they cited included an ovary that is occasionally lobed, tegument with fine spines, eyespot pigments that are scattered around the pharynx and the oesophagus, presence of a pars prostatica with a pair of diverticula, and surrounded by glandular cells. In their specimens from Nago, Okinawa “ five specimens had much wider bodies” and “testis with one or two deep longitudinal incisions at posterior margin”. They considered these features as variations. We cannot confirm these characteristics in our Kuwaiti specimens; some of our specimens contain one or two very small pigments suspected to be remnants of eyespots. The Kuwaiti material may not have been as fresh as that of MACHIDA and KURAMOCHI (2000) which could explain absence of tegumental spines. We have no reason to suspect that their specimens or the Arabian Gulf material represent a new species. As far as we can determine, this is the third report of this species and the finding represents new geographic and host records.

Figures

Fig. 5. Treptodemuslatus MANTER, 1961from Hemiramphus marginatus. Ventral view.Scale1.00 mm