Parorchis Nicoll, 1907

Dronen, Norman O. & Blend, Charles K., 2008, Observations on the Parorchis acanthus complex (Philophthalmidae: Parorchiinae) with the description of three new species of Parorchis Nicoll, 1907 and the replacement of the preoccupied junior homonym Paratrema Dronen & Badley, 1979 with Stenomesotrema nomen novum, Zootaxa 1843 (1), pp. 1-23 : 3

Parorchis Nicoll, 1907

(syn. Zeugorchis Nicoll, 1906 , preoccupied)

Species currently assigned to Parorchis can be divided into 2 basic body types: 1. those where the body has a barbell-like or hourglass shape, the head collar is rudimentary and restricted to the area immediately around the oral sucker, the testes are side by side to tandem, there are usually 2 rows of corner spines on the head collar, the acetabulum has a definite pre-midbody placement, and where the forebody is wider than the hindbody, as seen in both Parorchis numenii (syn. Paratrema numenii ) ( Figs. 1–3) where the testes are diagonal to tandem and the acetabulum is about 1/4 the distance of the body length from the anterior end, and Parorchis asiaticus where the testes are side by side and the acetabulum is about 1/3 the distance down the body from the anterior end ( Fig. 4); and 2. the Parorchis body type ( Fig. 5), where the body is pyriform, the head collar is strongly developed forming definite shoulder-like corners, the acetabulum is situated in the middle third of the body, the testes are side by side, and there is a single continuous row of circumoral spines on the head collar. There appears to be 2 general subtypes of the Parorchis body type: subtype 1 - those that are like P. acanthus , as originally described by Nicoll (1906) from the herring gull ( Fig. 5), where the testes are smooth to slightly irregular (not deeply lobed) and the esophagus generally lacks diverticuli ( P. acanthus australis Angel, 1954 ; P. belopoloskoi ; P. crassus [this species may have esophageal diverticuli]; P. gedoelsti ; P. holotestis ; P. komi ); and subtype 2 - those that are like P. acanthus , as redescribed by Nicoll (1907b) from the mew gull ( Figs. 6– 16), where the testes are irregular and deeply lobed and the esophagus has lateral diverticuli ( P. acanthus numenii Oshmarin, 1963 ; P. asiaticus magnus Belopol’skaia, 1963; P. avitus ; P. chauhani ; P. parvicollis ; P. proctobium ; P. schachtachtinskoi ; P. snipis ).