Patterns of diversification and phylogenetic structure in the dorsolateral head musculature of Neotropical electric eels (Ostariophysi: Gymnotiformes), with a myological synonymy Peixoto, Luiz Antônio Wanderley de Pinna, Mário Neotropical Ichthyology 2022 e 210009 2022-04-01 20 1 1 117 328V Korringa, 1970 Korringa 1970 [804,1143,1496,1521] Sternopygidae Archolaemus Animalia Gymnotiformes 44 45 Chordata genus  The rictalisoriginates in the preopercle, sympletic, quadrate and hyomandibula. The lateralmost fibers of the ventral portion of the rictalisis 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 stegalisarises from the hyomandibula, pterosphenoid, metapterygoid, and quadrate; and converges into the meckelian tendon which, in turn, inserts on the coronomeckelian bone. Usually, the stegalisoverlaps only the ventral portion of the adductor arcus palatini, except in  A. orientalis, where the stegalisis positioned laterally only to the mid-posterior portion of the adductor arcus palatini, overlapping it partially. The segmentum mandibularisoccurs only in  A. luciaeand arises from the mandibular tendon, enters the mandible mesially and inserts on the anguloarticular and dentary. The segmentum mandibularisis located dorsally to Meckel’s cartilage, extending about 40% of the dorsal portion of this cartilage. The segmentum mandibularisis absent in the remaining species ( Fig. 9). The course of the ramus mandibularis trigeminusnerve is lateral to the stegalisand mesial to the rictalisand malaris.  Levator arcus palatini.The levator arcus palatinihas 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 palatiniare parallel to the dilatator operculi, with no overlap between the two muscles.