Circumvitellatrema , Dronen, Norman O., Greiner, Ellis C., Ialeggio, Donna M. & Nolan, Thomas J., 2009

Dronen, Norman O., Greiner, Ellis C., Ialeggio, Donna M. & Nolan, Thomas J., 2009, Circumvitellatrema momota n. gen., n. sp. (Digenea: Cyclocoelidae: Cyclocoelinae) from a captive-hatched blue-crowned motmot, Momotus momota (Momotidae), Zootaxa 2161, pp. 60-68: 62

publication ID 10.5281/zenodo.188988

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n. gen.

Circumvitellatrema  n. gen.

Type species: Circumvitellatrema momota  n. gen., n. sp.

Etymology: The genus designation comes from the Latin “circum”, meaning around; “vitell”, meaning yolk and “trema”, referring to Trematoda to reflect the unusual pattern of the vitelline fields where both the anterior and posterior extremes are confluent forming a complete loop in the body in members of the new genus.

Diagnosis: Cyclocoelidae Stossich, 1902  ; Cyclocoelinae Stossich, 1902. Body large, flat, tapered anteriorly. Oral sucker if present, poorly developed. Acetabulum absent. Mouth subterminal; prepharynx short; pharynx well developed, wider than long; esophagus longer than prepharynx. Ceca long, united near posterior extremity forming cyclocoel. Testes smooth, sometimes irregular, slightly diagonal, located in posterior third of body. Ovary spherical, intertesticular, forming triangle with testes. Genital pore postpharyngeal. Vitelline follicles distributed dorsally along ceca from level of cecal bifurcation to near posterior extremity; vitelline fields confluent anteriorly and posteriorly forming continuous loop in body. Uterus extending from immediately anterior to posterior testis anteriorly to near level of pharynx, not invading posttesticular space. Eggs indistinctly operculate ( Fig. 1View FIGURES 1 – 3). Excretory vesicle Y to V-shaped. Parasites of lungs and air sacs of birds.

Remarks: The new genus has an intertesticular ovary forming a triangle with the testes placing it in Cyclocoelinae. Dronen (2007) recognized 2 genera of Cyclocoelinae based largely on the position of the genital pore relative to the pharynx: Cyclocoelum  , in which the genital pore is prepharyngeal and Selfcoelum  in which the genital pore is postpharyngeal. Dronen & Kinsella (2009) added a third genus, Psophiatrema Dronen & Kinsella, 2009 to the subfamily in which the vitelline fields were unlike those of Cyclocoelum  and Selfcoelum  by being confluent posteriorly. The new genus is most similar to Psophiatrema by having a postpharyngeal genital pore and vitelline fields that are confluent posteriorly, but differs from members of this genus by having the vitelline fields also confluent anteriorly forming a continuous loop in the body. The nature of the extent of the vitelline fields is considered to be a reasonably reliable and consistent characteristic, and has commonly been used to distinguish genera in most cyclocoelid descriptions and keys (e. g. Kanev et al., 2002; Dronen, 2007; Dronen & Kinsella, 2009). The subfamily diagnosis of Cyclocoelinae as proposed by Dronen & Kinsella (2009) should be emended to accommodate the new genus in which the vitelline fields are confluent anteriorly and posteriorly by changing it to reflect that the vitelline fields may be separated (not confluent) at both the anterior or posterior extremes of the body, confluent posteriorly only, or confluent both anteriorly and posteriorly. The only other genus in which this peculiar distribution of the vitelline follicles occurs in the cyclocoelids appears to be in Skrjabinocoelum Kurashvili, 1953, as represented by Skrjabinocoelum petrowski Kurashvili, 1953 described from the Jack snipe, Lymnocryptes minimus (Brünnich)  , from Russia ( Kurashvili 1953). However, Skrjabinocoelum currently is assigned to Skrjabinocoelinae Dronen, 2007 because the ovary is intertesticular forming a straight line with the nearly side by side testes ( Dronen 2007).