Natural and Experimental Infections of Centrarchid Fishes by the Digenetic Trematode Proterometra macrostoma: Detection of New Infections and Host Histopathology

Proterometra epholkos sp. n. (Digenea: Azygiidae) from Terrapin Creek, Alabama, USA: Molecular characterization of life cycle, redescription of Proterometra albacauda, and updated lists of host and geographic locality records for Proterometra spp. in North America

“…Proterometra presently accommodates flukes that mature in primary division freshwater fishes of Centrarchidae (species of Lepomis, Micropterus, and Pomoxis) [1,35], Cottidae (Cottus spp.) [28,29], Percidae (Etheostoma spp.…”

“…This makes the assessment of operational taxonomic units based on cercarial morphology alone challenging, especially given the low number of reported diagnostic characteristics. Various workers have treated morphology, behavior, and host-parasite relationships of the cercariae [13,[6][7][8][9][10][11][12]33,[66][67][68][69][70][71][72], development and morphology of the eggs [35,73] and adults [1,6,15,[21][22][23][24][25]28,33,35], and general attributes of the intra-molluscan stages, sporocyst and redia [11,14,74]. Moreover, 8 cercarial strains of P. macrostoma have been morphologically characterized from Lake Erie [13], Kentucky [8,75], Michigan [8], and Ohio [8].…”

“…13); ventral furcae 1100-1340 (1250, 10) or 14-20% (17%, 10) of cercaria length, 1420-1840 (1636, 10) or 1.2-1.5 (1.3, 10)× wider than longer.Tail stem cavity positioned in anterior portion of tail stem, thin walled, not strongly muscular. Withdrawn distome (= cercarial body) 1340-2040 (1604, 10) long or 17-28% (22%, 10) of cercaria length, 660-880 (760, 10) wide or 2-3 (2, 10)× longer than wider, specimens with 2-42 (20, 10) stage 1 eggs (see[35]) in proximal end of uterus near ootype. Mamillae usually bearing spines, maximum length 115-185 (147, 10), maximum width 185-290 (241, 10) or 1.2-2.5 × wider than longer, cercaria length with mamillae 3000-4600 (3748, 10) or 45-56% (52%, 10) of cercaria length, cercaria length without mamillae 2700-4000 (3217, 10) (Figs.…”

“…Of note is that, in an abstract, Dickerman [40] stated that he succeeded in feeding cercariae to "fish and turtles;" however, no subsequent work, including Dickerman [13,24], mentions a turtle host for any species of Proterometra. These flukes have a macroscopic, 3-22 mm long, furcocystocercous cercaria that can be progenetic [25,29,41] and flamboyantly swims in the water column, perhaps luring the fish definitive host to bite and/or swallow it [22,35]. The cercarial body (="distome") is typically withdrawn inside a cavity (="tail cavity") within the anterior or midbody portion of the tail stem before cercarial emergence (="shedding") from the gastropod.…”

New species of Proterometra (Digenea: Azygiidae) and its life cycle in the Chickasawhay River, Mississippi, USA, with supplemental observations of Proterometra autraini

“…Because adjacent eggs as well as eggs located in the proximal portion of the female reproductive tract were not hatched (opercula were not detached from eggs) and because the paratypes of LP were in excellent condition, we doubt that the apparent en-utero hatching of miracidia was an artifact of fixation or mounting. Although only length and width of eggs have been used previously to differentiate species of Proterometra, we think that additional features associated with the eggs, including presence/absence, density, distribution, and size of fimbria ("filaments" of LP) or polar papillae [2] as well as their level of uterine development [49] may help differentiate species.…”