Hamacreadium cribbi Bray & Justine, 2016

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 : 162

Hamacreadium cribbi Bray & Justine, 2016

( Figure 2 a)

Records. From the redthroat emperor, Lethrinus miniatus (Forster) ( Perciformes : Lethrinidae ), off New Caledonia as H. mutabile by Durio & Manter (1968) and as Neolebouria sp. A. by Justine et al. (2010b).

Remarks. This recently described species was well characterised, is clearly consistent with the morphological concept of Hamacreadium , and demonstrably belongs in the genus on the basis of molecular analyses (Bray et al. 2016; Bray & Justine 2016). Justine et al. (2010b) reported four additional Lethrinus Cuvier hosts, but Bray & Justine (2016) characterised the species based only on the specimens from L. miniatus . Morphologically, this species is most similar to Hamacreadium morgani Baz, 1946 , which is considered here the senior synonym for several species reported from Lethrinus fishes of the Red Sea (see below). Bray & Justine (2016) did not distinguish their specimens from the description of Baz (1946). Both species are large and have larger eggs relative to others retained in the genus, and it appears that the only character separating the two might be the condition of the cirrus-sac; in H. cribbi it is distinctly sigmoid and reaches towards, and sometimes just beyond, the posterior edge of the ventral sucker, whereas in H. morgani and its synonyms, the cirrus-sac is straight to curved and just overlaps the anterior edge of the ventral sucker or is entirely anterior to it. This character is not entirely reliable, because the relative position of these organs is susceptible to the effects of flattening, but none of the descriptions hypothesised to represent H. morgani is of sufficient quality to allow more rigorous distinction.

Figures

FIGURE 2. Reproduction with modification of type illustrations for (a) Hamacreadium cribbi Bray & Justine, 2016 and (b) Hamacreadium hainanense Shen, 1990. 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.