Circumvitellatrema phasidi Stunkard 1929, n. comb.
Creators: name: Dronen, Norman O.
name: Blend, Charles K.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Trematoda
Plagiorchiida
Cyclocoelidae
Circumvitellatrema
Circumvitellatrema phasidi

description: C. phasidi (Stunkard, 1929) n. comb.
Type host. Plumed guineafowl, Guttera plumifera Cassin (Galliformes: Numididae)— Boyko (1996). Type locality. Ngayu, Democratic Republic of the Congo (previously the Belgian Congo and the Republic of Zaire)— Boyko (1996).
Previously proposed synonym. Cyclocoelum (Cyclocoelum) phasidi Stunkard, 1929 — Bashkirova (1950). Remarks. This species was originally described as Cyclocoelum phasidi Stunkard, 1929. Stunkard (1929) indicated that there were three distributions of the vitelline fields represented in the three specimens used in the description of this species: 1. “continuous posteriorly but interrupted anteriorly” (confluent posteriorly); 2. “completely encircle the ceca” (confluent at both ends of the worm); and 3. “continuous anteriorly and the stem of one side does not quite reach the posterior end, leaving a short gap” (not confluent posteriorly). Based on the original description and Fig. 36 of the holotype in the original description the ovary is intertesticular forming a triangle with the testes in these specimens, placing these specimens in Cyclocoelinae. The genital pore was originally described as being ventral to the pharynx, but appears to be prepharyngeal in Fig. 36, which would suggest placement of this specimen in Cyclocoelum. However, in species of Cyclocoelum generally the vitelline fields are considered not to be confluent posteriorly rather than being confluent as in distribution 1 from the above list from Stunkard 1929 (type specimen of this species). The anterior end of the type specimen appears to be contracted, which may account for the nearly prepharyngeal appearance of the genital pore in the specimen shown in Fig. 36. If the placement of the genital pore is postpharyngeal in the specimen represented in Fig. 36, then this specimen would be placed in Psophiatrema (Cyclocoelinae). In the case of the second distribution above (confluent anteriorly and posteriorly), the encirclement of the ceca by the vitelline fields suggests that this specimen should be assigned to Circumvitellatrema (Cyclocoelinae). In the third type of vitelline distribution where the vitelline fields are described as being confluent anterior but not at the posterior end of the body, it is likely that the observation reported of the posterior “short gap” in this specimen is an artifact and that this specimen would likely also be assigned to Circumvitellatrema. Occasionally we have observed similar anomalies in Circumvitellatrema momota Dronen, Greiner, Ialeggio & Nolan, 2009, but in nearly all these cases it was because the posterior confluence was hidden by the cyclocoel and/or the egg-laden uterus. Similarly, we have noted that the anterior confluence of the vitelline fields in C. momota are not always obvious and can be hidden in some specimens by the intestinal bifurcation and cirrus sac. Although it is quite possible to have multiple species present in the same host species and indeed in the same host, we believe all three of these specimens represent a species of Circumvitellatrema. In this case, two specimens came from a Guinea fowl from Niapu in 1913, while the third (Fig. 36) came from Ngayu in 1909. That being said, in our view, there appears to be enough observations related to the variability of the extent of the vitelline fields in the literature that suggest that the posterior confluence of the vitelline fields, or the lack thereof, may indeed need to be more thoroughly documented. Rudimentary oral sucker present—Stunkard (1929).
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 33, DOI: 10.11646/zootaxa.4053.1.1, http://zenodo.org/record/237117