Hamacreadium lethrini Yamaguti, 1934

Martin, Storm B., Cutmore, Scott C., Ward, Selina & Cribb, Thomas H., 2017, An updated concept and revised composition for Hamacreadium Linton, 1910 (Opecoelidae: Plagioporinae) clarifies a previously obscured pattern of host-specificity among species, Zootaxa 4254 (2), pp. 151-187 : 164

Hamacreadium lethrini Yamaguti, 1934

( Figure 3 b)

Records. From the Chinese emperor, Lethrinus haematopterus Temminck & Schlegel , off Japan by Yamaguti (1934). From Le. haematopterus and the paddletail snapper, Lutjanus gibbus (Forsskål) , off the Philippines by Velasquez (1975). From Lu. gibbus and a single specimen from the longfin emperior, Lethrinus erythropterus Valenciennes [as Lethrinus hypselopterus Bleeker ] off the Philippines by Fischthal & Kuntz (1964). From the thumbprint emperor, Lethrinus harak (Forsskål) , and Lu. fulviflamma off Japan by Dyer et al. (1988). From grey large-eye bream, Gymnocranius griseus (Temminck & Schlegel) (Lethrinidae) , and Le. miniatus off China by Shen (1985). From Lu. johnii and Acanthopagrus latus off China by Wang et al. (1992).

Remarks. The description of this species is finely detailed and is entirely consistent with the concept of Hamacreadium . Yamaguti (1934) found his specimens to differ from H. mutabile only by morphometric comparison and Bray & Cribb (1989) synonymised the two, but, based on the new analysis, this species is again recognised as distinct here. In addition to the geographical separation, H. lethrini has a distinctly post-bifurcal vitelline distribution, whereas that of H. mutabile is consistently pre-bifurcal ( Linton 1910). The type-host, Le. haematopterus , is noteworthy in that it is the only lethrinid restricted to temperate waters ( Lo Galbo et al. 2002); the true identity of the fish reported by Velasquez (1975) in Philippine waters is most likely the morphologically similar Le. miniatus (see Lo Galbo et al. 2002). The specimens (SI NMNH IZ #1338501-1/2, #1363942-1) collected by Fischthal & Kuntz (1964) from Lu. gibbus appear to represent a distinct species. In these specimens the intestine bifurcates in a broad arch, the ovary has many lobes and the uterus extends posteriorly beyond the ovary, whereas in H. lethrini sensu Yamaguti (1934) the intestine bifurcates at a sharp angle, the ovary is tri-lobed and the uterus is distinctly restricted anterior to the ovary. The specimen from Le. erythropterus (SI NMNH IZ #1338500) is damaged and cannot be identified to species. The specimen (SI NMNH IZ #1375247) collected from Le. harak near the type-locality by Dyer et al. (1988) does appear to represent H. lethrini ; the intestine bifurcates at a sharp angle and the uterus is restricted anterior to the ovary, it differs only from the original description in that it has many ovary lobes. Shen (1985) did not provide a description or illustration. The reports of H. lethrini and H. mutabile of Wang et al. (1992) are interpreted here to represent H. hainanense (see above).

Figures

FIGURE 3. Reproduction with modification of type illustrations for (a) Hamacreadium interruptum Nagaty, 1941 and (b) Hamacreadium lethrini Yamaguti, 1934. Abbreviations: C, caecum; Cs, cirrus-sac; Ep, excretory pore; Ev, excretory vesicle; Gp, genital pore; O, ovary; Oes, oesophagus; Os, oral sucker; P, pharynx; T, testis; U, uterus; Vf, vitelline follicles; Vs, ventral sucker. Scale: 1000 µm, 1000 µm.