Rhabdolichops Eigenmann & Allen, 1942

Peixoto, Luiz Antônio Wanderley & de Pinna, Mário, 2022, Patterns of diversification and phylogenetic structure in the dorsolateral head musculature of Neotropical electric eels (Ostariophysi: Gymnotiformes), with a myological synonymy, Neotropical Ichthyology (e 210009) 20 (1), pp. 1-117 : 48-49

Rhabdolichops Eigenmann & Allen, 1942

Adductor mandibulae. The rictalis originates in the quadrate, sympletic, preopercle, and hyomandibula. The lateralmost fibers of the ventral portion of the rictalis is restricted to the anterior margin of the preopercular fossa. That section inserts solely on the coronoid process and anguloarticular, with some lateralmost fibers associated with the buccopalatal membrane. The stegalis arises from the hyomandibula, metapterygoid, and quadrate; and converges into the meckelian tendon which, in turn, inserts on the coronomeckelian bone, with some anterodorsal fibers converging to the mandibular tendon. The stegalis is located laterally in relation to the basal region of the endopterygoid, overlapping it completely; except in R. zareti , R. lundbergi , and R. nigrimans , in which the stegalis overlaps only the posterior portion of the basal region of the bone.

The segmentum mandibularis is located dorsally to Meckel’s cartilage, extending about its entire length of the dorsal portion of this cartilage (Dutra et al., 2021: fig. 41B); or extending about 70% of the dorsal portion of this cartilage in R. lundbergi and R. nigrimans . The course of the ramus mandibularis trigeminus nerve is lateral to the stegalis and rictalis, and mesial to the malaris.

Levator arcus palatini. The levator arcus palatini has a roughly parallelogram shape. Within Rhabdolichops , the generalized condition is the origin of the levator arcus palatini arising from the sphenotic in R. lundbergi and R. nigrimans , including the pterosphenoid in the remaining species, or the frontal solely in R. troscheli . The insertion occurs on the hyomandibula, and includes the preopercle in R. zareti . The origin of the levator arcus palatini is equal to a half of its insertion in R. zareti , R. lundbergi , and R. nigrimans ; or equal to its insertion in the remaining species. At the insertion point, the anterolateral, anteromesial and posterolateral fibers are lateral to the malaris; while and posteromesial fibers are mesial to the latter, except for the R. zareti , with all fibers lateral to the malaris.