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 1 117 http://dx.doi.org/10.1590/1982-0224-2021-0009 journal article 10.1590/1982-0224-2021-0009 1982-0224 13332563 Archolaemus Korringa, 1970 Adductor mandibulae. The malaris is positioned dorsolaterally to the dorsal portion of the rictalis and completely lateral to the stegalis (Dutra et al ., 2021: fig. 15), except for Archolaemus orientalis in which the malaris overlaps partially the stegalis . The rictalis originates in the preopercle, sympletic, quadrate 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, with some lateralmost fibers associated with the buccopalatal membrane and transverse ligament. The stegalis arises from the hyomandibula, pterosphenoid, metapterygoid, and quadrate; and converges into the meckelian tendon which, in turn, inserts on the coronomeckelian bone. Usually, the stegalis overlaps only the ventral portion of the adductor arcus palatini , except in A. orientalis , where the stegalis is positioned laterally only to the mid-posterior portion of the adductor arcus palatini , overlapping it partially. The segmentum mandibularis occurs only in A. luciae and arises from the mandibular tendon, enters the mandible mesially and inserts on the anguloarticular and dentary. The segmentum mandibularis is located dorsally to Meckel’s cartilage, extending about 40% of the dorsal portion of this cartilage. The segmentum mandibularis is absent in the remaining species ( Fig. 9 ). The course of the ramus mandibularis trigeminus nerve is lateral to the stegalis and mesial to the rictalis and malaris . Levator arcus palatini. The levator arcus palatini has a triangular shape, originating from the ventral margin of the pterosphenoid and sphenotic, inserting in the hyomandibula. The relative size of origin is equal to a half of its insertion. At the insertion point, the anterolateral, anteromesial and posterolateral fibers are lateral to the malaris ; while and posteromesial fibers are mesial to the latter. The posterodorsal fibers of the levator arcus palatini are parallel to the dilatator operculi , with no overlap between the two muscles.