Cyclocoelum halcyonis MacCallum 1921, n. comb.
Creators: name: Dronen, Norman O.
name: Blend, Charles K.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Trematoda
Plagiorchiida
Cyclocoelidae
Cyclocoelum
Cyclocoelum halcyonis

description: S. halcyonis (MacCallum, 1921) n. comb.
Type host. Rudy kingfisher, Halcyon coromando (Latham) (given as Halcyonis coromando by MacCallum 1921), (Coraciiformes: Halcyonidae).
Type locality. Luzon, Republic of the Philippines.
Remarks. This species was originally described as Cyclocoelum halcyonis MacCallum, 1921 but was considered a synonym of Cyclocoelum obscurum (Leidy, 1887) by Tubanqui (1932), Witenberg (1928), Bashkirova (1950) and of C. mutabile (Zeder, 1800) by Joyeux & Baer (1927). MacCallum (1921) provided a minimal description of this species and a figure of a longitudinal section (separating the ventral half from the dorsal half) of an adult. It appears as if MacCallum may have followed Braun (1901), who mistakenly considered the pharynx of cyclocoelids to be an oral sucker because what appears to be the muscular pharynx in Fig. 84 is labelled “m”, presumably referring to the mouth, and a much smaller structure posterior to it that appears to be the genital pore is labelled as the pharynx. MacCallum (1921) also apparently considered the ovary to be intertesticular, forming a triangle with the testes as in Monostomum mutabile (= Cyclocoelum mutabile) (Cyclocoelinae). According to MacCallum (1921) this species has the genital pore in the region of the pharynx similar to that of species of Cephalogonimus Poirier, 1886, which suggests that this species has a prepharyngeal genital pore and vitelline fields that are not confluent posteriorly (“The vitellarium consists of a narrow line of glands which, like the intestine, surround the margin of the body, except a small portion at the anterior end.”), which would place it in Cyclocoelum. However, the placement of the genital pore is postpharyngeal in Fig. 84, which would place this species in Selfcoelum. Unlike species of Cyclocoelum, Fig. 84 of the original description, although somewhat unclear, appears to show that the intertesticular ovary may be nearly in a straight line with the tandem testes (Hyptiasminae). If that is the case and the genital pore is prepharyngeal, this species would be placed in Prohyptiasmus, while if the genital pore is postpharyngeal it would be assigned to Morishitium. Given the available information, this species is tentatively placed in Selfcoelum because the ovary appears to be intertesticular forming a triangle with the testes (Cyclocoelinae), the genital pore is postpharyngeal and the vitelline fields are not confluent posteriorly. Until the position of the ovary relative to the testes is better documented, we recommend that this species be considered in any comparison of specimens in Cyclocoelinae or Hyptiasminae (where the vitelline fields are not confluent posteriorly) to existing species of Cyclocoelum, Selfcoelum, Prohyptiasmus and Morishitium. This species could not be included in our key to species of Selfcoelum because of the incomplete description and lack of a suitable illustration. No oral or ventral suckers described—MacCallum (1921).
description: Published as part of Dronen, Norman O. & Blend, Charles K., 2015, Updated keys to the genera in the subfamilies of Cyclocoelidae Stossich, 1902, including a reconsideration of species assignments, species keys and the proposal of a new genus in Szidatitreminae Dronen, 2007, pp. 1-100 in Zootaxa 4053 (1) on page 21, DOI: 10.11646/zootaxa.4053.1.1, http://zenodo.org/record/237117