Laruella, Toma & Scholz & Choudhury & McAllister, 2022

Toma, Scholz, s, Choudhury, Anindo & McAllister, Chris T., 2022, A young parasite in an old fish host: A new genus for proteocephalid tapeworms (Cestoda) of bowfin (Amia calva) (Holostei: Amiiformes), and a revised list of its cestodes, International Journal for Parasitology: Parasites and Wildlife 18, pp. 101-111 : 102

3.1. Laruella new genus

Generic diagnosis: Onchoproteocephalidea , Proteocephalidae . Testes, ovary, vitellarium and uterus medullary. Large worms. Strobila robust, acraspedote, with immature proglottids conspicuously wider than long. Scolex globular, with four prominent lobes bearing uniloculate suckers; tear-shaped inner rim of suckers bearing sphincter. Apex of scolex without apical organ. Inner longitudinal musculature well-developed, formed by single circle of small bundles of muscle fibres. Ventral osmoregulatory thin-walled, wide, situated ventrolateral to vitelline follicles. Dorsal canals thick-walled, narrow, situated mediodorsal to vitelline follicles. Testes medullary, in two or three incomplete layers, in one large field between lateral bands of vitelline follicles, with some testes anterodorsal to ovary. Cirrus-sac large, thin-walled, containing few loops of vas deferens and long cirrus. Ovary medullary, bilobed, with narrow lateral wings. Vagina anterior to cirrus-sac, with circular vaginal sphincter at distance from genital atrium, at level of proximal third of cirrus-sac; terminal (distal) part of vagina thick-walled, lined with chromophilic cells. Gonopores irregularly alternating, pre-equatorial. Vitelline follicles forming two L-shaped lateral bands from anterior to posterior margins of proglottids, with posterior field of follicles turned inwards (medially) ventrally. Uterus medullary, with numerous lateral diverticula, with Type 2 of uterine development of de Chambrier et al. (2004). Uterine pore large, elongate. Eggs ellipsoid. Parasites of bowfin, rarely (incidentally?) in other predatory fish.

Type and only species: Laruella perplexa ( La Rue, 1911) new combination.

Etymology: The generic name honours George Roger La Rue (1882–1967), American parasitologist, whose monograph on proteocephalid tapeworms published in 1914 represents a milestone in the systematics of this cestode group. The name is treated as femininum.