RH: Warren and Bullard – New blood fluke and ITS life cycle first elucidation of a blood fluke (Electrovermis zappum N. gen., N. SP.) life cycle including a chondrichthyan or bivalve

We describe a new fish blood fluke (Digenea: Aporocotylidae: Electrovermis zappum n. gen., n. sp.) and its life cycle in the intertidal zone adjacent to Mobile Bay (north-central Gulf of Mexico). This is the first elucidated aporocotylid life cycle that includes a chondrichthyan definitive host or a bivalve intermediate host. The new species undergoes asexual reproduction within the gonad of the variable coquina clam before maturing in the heart of the lesser electric ray. These adults and cercariae had identical 28S, 18S, and ITS2 nucleotide sequences. The new genus is similar to Ogawaia by having an inverse U-shaped intestine, a looping testis, and a uterus having distinct ascending and descending segments. It differs by having a body that is ≥ 30 × longer than wide, a testis with>30 curves, an obvious cirrus sac enveloping an extremely elongate cirrus, an ovary anterior to the seminal vesicle, and a post-gonadal uterus. The new species further differs from the type species of Ogawaia (Ogawaia glaucostegi Cutmore et al., 2018) by having a massive seminal vesicle (>10% of body length), a cirrus sac enveloping an extremely elongate cirrus, and a slightly sinuous uterus. Histology confirmed gametogenesis in an infected coquina clam but no discernable cellular response to infection was observed. We also i) characterize a second morphologically and genetically distinct cercaria (perhaps representing an innominate chondrichthyan aporocotylid) infecting the green jackkn...
Source: International Journal for Parasitology: Parasites and Wildlife - Category: Parasitology Source Type: research