Description

Diagnosis: Body elongate, fusiform, comprising body proper (cephalic region, trunk, and peduncle), and haptor. Tegument thin, smooth. Cephalic lobes 2, terminal; each containing spike sensilla, portion of head organ. Cephalic glands comprising 2 bilateral groups of gland cells posterolateral to pharynx. Eyespots absent. Mouth subterminal, midventral. Pharynx comprising 2 tandem bulbs; proximal bulb glandular, muscular; distal bulb muscular with 8 digitiform projections occasionally protruding through mouth. Intestinal ceca 2, lacking diverticula, terminating blindly in posterior trunk or peduncle. Worms oviparous, protandrous. Gonads tandem, intercecal. Testis postgermarial (when present), reduced in adult specimens and usually becoming nonfunctional as female reproductive system develops. Two tandem seminal vesicles posterior to male copulatory organ (MCO). Copulatory sac absent. MCO allantoid, unarmed, variably bent or coiled, appearing muscular. Accessory copulatory sclerite present. Vas deferens, prostate, prostatic reservoir not observed. Germarium (in adults) submedial, with internal fertilization chamber usually filled with sperm; oviduct variably coiled, originating from dorsal surface of germarium; ootype distal to elongate oviduct, surrounded by large Mehlis’ gland. Uterus containing single egg (or empty); uterine pore dextroventral, submarginal at level of MCO. Vagina absent. Egg with short flared proximal filament embedded in amorphous droplet. Numerous vitelline follicles in postgermarial field of trunk, pregermarial follicles few or absent; vitelline ducts forming inverted U or backward h. Haptor ventrally concave, originating from ventral side of expanded posterior end of peduncle, armed with pair of ventral anchors, 16 identical hinged hooks, and slightly concave ventral plate overlying anchor pair; anchors with points usually directed dorsolaterally; bars absent. Hooks evenly spaced along lateral and posterior margins of haptor, with extrahamular distribution (see Kritsky & Mizelle 1968). Parasitic on external surface of neotropical catfishes assigned to the Loricariidae.

Common Names

Taxonomic Hierarchy

Kingdom: Animalia

Phylum: Platyhelminthes

Class: Monogenea

Order: Gyrodactylidea

Family: Gyrodactylidae

Genus: Atopogyrodactylus

Species: Atopogyrodactylus Kritsky, Boeger & Patella, 2020