Sternarchorhamphus Eigenmann, 1905

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 : 66

Sternarchorhamphus Eigenmann, 1905

Adductor mandibulae. The malaris arises from the mid-dorsal portion of the hyomandibula, preopercle, and simpletic; converging anteriorly to the buccopalatal membrane, where the anterodorsal portion differentiates into an endomaxilar ligament, equal to a half of the fibrous portion of the malaris, to an insertion at the posteromesial margin of the premaxilla; and the anteroventral fibers converges to the same membrane which, in turn, attaches to the dorsal and posterior margins of the maxilla ( Fig. 26 ).

The ricto-stegalis originates in the hyomandibula, quadrate, metapterygoid, sphenotic, parasphenoid, pterosphenoid, and sympletic. At its origin, the ricto-stegalis is a single mass of fibers, and partially differentiated towards their insertion sites. The fibers corresponding to the presumed rictalis inserts mainly into the posterior margin of the anguloarticular; and the presumed stegalis converges into the meckelian tendon to an insertion to the coronomeckelian bone. The ramus mandibularis trigeminus nerve lies mesial to the segmentum facialis.

Levator arcus palatini. The levator arcus palatini has a trapezoidal shape, originating from the ventral margin of the frontal and sphenotic and inserting onto the hyomandibula. The origin of the levator arcus palatini corresponds to its insertion. At the insertion of the levator arcus palatini, all fibers are located laterally to the malaris; and with only the posterodorsal fibers being mesial to the dilatator operculi, where the anterior margin of the dilator operculi exceeds the median portion of the levator arcus palatini.

Figures

FIGURE 26 | Lateral view of dorsolateral musculature of Sternarchorhamphus mulleri (Apteronotidae), USNM 373030, 222.2 mm LEA. Anatomical abbreviations in Tab. 1. Scale bar = 10 mm.