Mesocoelium

Calhoun, Dana M. & Dronen, Norman O., 2012, A reevaluation of specimens of Mesocoelium monas (Platyhelminthes: Digenea: Mesocoeliidae) from the Natural History Museum, UK and the United States National Parasite Collection, USA, Zootaxa 3589, pp. 1-29 : 10

Mesocoelium americanum— USNPC 0 79344.00

( Figure 6, Table 2)

Host: Anolis sagrei (Dumeril & Bibron) , brown anole ( Squamata : Polychrotidae ).

Locality: Sarasota, Florida. (Introduced)

Description: Based on one specimen: Body 2,050 by 640; forebody 676 long, representing 33% of body length. Mouth subterminal; oral sucker spherical, 203 by 213; prepharynx absent; pharynx spherical, 85 by 108; ratio of width of pharynx to width of oral sucker 1:2.1; esophagus 260 long; ceca terminating posterior to posterior margin of ovary, occupying 37% of postovarian space. Ventral sucker subspherical, situated posterior margin of anterior 1/3 of body, 163 by 185; ratio of ventral sucker width to oral sucker width 1:1.2. Testes oval to subspherical; left testis 135 by 125; right testis not visible. Genital pore submedian, located immediately posterior to midlevel of esophagus. Cirrus sac clavate, 200 long, representing 10% of body length. Ovary circular, 138 by 138; postovarian space 1,120 long, representing 55% of body length. Uterus extensive, filling hindbody. Vitelline follicles distributed in lateral fields from level of pharynx to near level of cecal ends posteriorly. Eggs 43 (40–45) by 25 (24–26). Excretory system I-shaped; Excretory pore terminal.

Remarks: This specimen appears to be rolled so that the gonads have become moved to the left. The poor quality of the specimen precluded observation of some structures (e.g. right testis).

Although this specimen has ceca surpassing the ovary posteriorly and a prebifurcal, submedian genital pore, and is assigned to the monas body type, it cannot be assigned specifically to M. monas . This specimen can be distinguished from M. monas by having vitelline fields that surpass the cecal ends posteriorly compared with terminating well short of the cecal ends (about the level of the anterior margin of the ovary), a shorter forebody (676 compared with 970), a narrower oral sucker (213 compared with 382), and a narrower ventral sucker (185 compared with 344).

This specimen is consistent with M. americanum by having a similar oral sucker width (213 compared with 208–360), a similar pharynx width (108 compared with 75–165), a similar ventral sucker width (185 compared with 125–238), a similar postovarian space length (1,120; 55% of the body length compared with 740–2,626; 62%), a similar cirrus sac length (200; 8% of the body length compared with 176; 8%), similar egg sizes (43 [40–45] by 25 [24–25] compared with 41 [39–45] by 24 [21–26]), and were collected from the same general geographical area (Texas compared with Florida).