1.1. Hooks of the scolex absent.	2
1.2 Sclerotized hooks of the scolex present.	3
2. Fusiform bothridia, without central constriction; medial longitudinal septum of the scolex originating from the posterior margin of the anterior loculus to the posterior margin of the bothridium; strobila craspedote; ovarian lobes symmetrical; paravaginal glandular cells absent	Rhinebothrium paratrygoni
2.1 Pedunculated bothridia; marginal and transverse septa of the scolex forming loculi; strobila acraspedote; ovarian lobes asymmetrical; paravaginal glandular cells present	Rhinebothroides glandularis
3. Septate bothridia, triloculated, with a pair of bifid hooks, medial and lateral branches of the hook subequal, with the distal cusp of the lateral branch surpassing the median region of the medial branch; loculi asymmetrical, anterior loculus conspicuously larger, reaching or exceeding the medial region of the scolex, posterior loculus well reduced, with the anterior edge entering the medial loculus; testes surpassing the cirrus sac, reaching the anterior margin of the ovary; vitellaria extending beyond the anterior margin of the ovary	Acanthobothrium quinonesi
3.1 Non-septate bothridia, with a pair of simple, non-bifurcated hooks; testes not exceeding the cirrus sac; vitellaria not exceeding the anterior margin of the ovary	4
4. Proximal portion of hook at an angle greater than 130° in relation to the anterior process of the base; furcation laterally arched, with cusp directed posteromedially; posterolateral genital pore, not exceeding the posterior portion of the ovary lobes	Potamotrygonocestus sp. 1
4.1 Proximal portion of hook at an angle of approximately 100° in relation to the anterior process of the base; furcation arched anteriorly, with cusp directed medially; terminal genital pore, surpassing the posterior portion of the ovary lobes	Potamotrygonocestus sp. 2