Studies on the Trematode Family Azygiidae. III. The Morphology and Life Cycle of Proterometra sagittaria n. sp.

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

“…Prior to Horsfall [1], wherein she proposed Proterometra, species of Proterometra were assigned to the collective group name Cercaria [3,17,20] (see International Code of Zoological Nomenclature [ICZN] page 70, article 67.14). Subsequent to the establishment of Proterometra, published works assigned the adults and cercariae separately, with the former being assigned to Proterometra and the latter to Cercaria [1,6,15,16,24,33]. To provide taxonomic resolution within Proterometra we discuss conspecificity of species assigned to Cercaria and treat those species as junior subjective synonyms of their conspecific adults assigned to Proterometra.…”

“…8,9). Seminal vesicle thin walled, highly convoluted, having swollen proximal region and narrow distal region; proximal region of seminal vesicle 305-710 (396, 5) long, 58-100 (91, 5) wide; distal region 95-260 (177, 5) long, 15-28 (24,5) wide, connected to pars prostatica via a short minute duct. Minute duct (=possibly "verschlussapparat" of Looss [58] in Horsfall [6], page 321) 10-30 (19,7) long, thin-walled, appearing to pierce proximal surface of ejaculatory duct (=thick walled pars prostatica) (Figs.…”

“…are principally differentiated based on cercarial morphology and behavior [1,15,21,22,24,25,28,29] (Table 4). Based on direct observations of cercarial specimens and a review of the published literature, the taxonomic validity of several cercarial characters is uncertain.…”

“…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].…”

“…(8 of 10 species) have indicated that these flukes undergo asexual reproduction in freshwater prosobranch snails, primarily of Elimia but also Pleurocera acuta [1,6], Lithasia obovata [4; see Graff [39] for synonymy], and Campeloma subsolidum [3], that range in rivers and streams draining to the Great Lakes, Gulf of Mexico, and Atlantic Ocean (Table 1). 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].…”