Patterns of diversification and phylogenetic structure in the dorsolateral head musculature of Neotropical electric eels (Ostariophysi: Gymnotiformes), with a myological synonymy Author Peixoto, Luiz Antônio Wanderley Author de Pinna, Mário text Neotropical Ichthyology 2022 e 210009 2022-04-01 20 1 http://dx.doi.org/10.1590/1982-0224-2021-0009 journal volume 10.1590/1982-0224-2021-0009 1982-0224 Pariosternarchus Albert & Crampton, 2006 Adductor mandibulae. The malaris arises from hyomandibula and preopercle, converging anteriorly to the buccopalatal membrane, where the anterodorsal portion differentiates into an endomaxilar ligament, equal to 2/3 to the fibrous portion of the malaris , to an insertion at the connective tissue between the anterior margin of the premaxilla and upper lip; and the anteroventral fibers converges into an ectomaxillary ligament that inserts at the posterolateral face of the maxilla. The ricto-stegalis originates in the parasphenoid, hyomandibula, sphenotic, quadrate, and metapterygoid. At its origin, the lateralmost portion of the ricto-stegalis , presumably corresponding to the rictalis , is separated dorsally from the fibers of the presumed stegalis by the levator arcus palatini , becoming continuous at their mid-portion and partially differentiated towards their insertion sites. The fibers corresponding to the rictalis inserts mainly into the coronoid process; and the presumed stegalis converges into an intersegmental aponeurosis weakly differentiated, where its ventral portion differentiates into the meckelian tendon to an insertion to the coronomeckelian bone, and the anterodorsal fibers converges into the mandibular tendon. The segmentum mandibularis is located dorsally to Meckel’s cartilage, extending about 60% of the dorsal portion of this cartilage. The ramus mandibularis trigeminus nerve trespasses the ricto-stegalis , and lies lateral to the presumptive stegalis and mesial to the rictalis and malaris . Levator arcus palatini. The levator arcus palatini has a roughly parallelogram shape, originating from the ventral margin of the frontal, pterosphenoid and sphenotic and inserting onto the hyomandibula. The origin of the levator arcus palatini is equal to its insertion. At the insertion, the anterolateral and posterolateral fiber bundles of the levator arcus palatini are lateral to the malaris and dorsolaterally to the presumed rictalis ; while its anteromesial and posteromesial bundles are medial to the malaris and to the presumed rictalis . The anteriormost fibers of the levator arcus palatini presents an aponeurotic aspect. This muscle has a mesial arrangement where the anterior margin of the dilator operculi exceeds its median portion.