GYMNOTIFORMES, Berg, 1940

Datovo, Aléssio & Vari, Richard P., 2014, The adductor mandibulae muscle complex in lower teleostean fishes (Osteichthyes: Actinopterygii): comparative anatomy, synonymy, and phylogenetic implications, Zoological Journal of the Linnean Society 171 (3), pp. 554-622 : 614

GYMNOTIFORMES

The Gymnotiformes , one of the morphologically most distinctive groups within the Teleostei, is characterized by the highest number of known synapomorphies amongst all the orders in that infraclass ( Fink & Fink, 1981, 1996; Albert, 2001; Wiley & Johnson, 2010). At least one additional synapomorphy, and the first involving myology, can be added to that list: [9] the levator arcus palatini passing lateral to the malaris ( Fig. 19 ; Aguilera, 1986; Marrero & Winemiller, 1993). In the vast majority of teleosts, the insertional portion of the levator arcus palatini conversely lies fully medial to the malaris. A levator arcus palatini lateral to the malaris was encountered elsewhere in the Teleostei solely in the Dactylopteriformes, Gadiformes , and Percopsiformes (A. Datovo pers. observ.; Eaton, 1935; Rosen & Patterson, 1969; Howes, 1988; Imamura, 2000; Endo, 2002). Notwithstanding these similarities, in light of the pronounced phylogenetic separation of these orders within the Acanthomorphata, these occurrences in those orders are most parsimoniously interpreted as convergences relative to the condition that characterizes the Gymnotiformes ( Fig. 27).

Figures

Figure 19. Adductor mandibulae and associated structures of Gymnotus carapo (Gymnotiformes: Gymnotidae), MZUSP 69391 (145.0 mm standard length). Left side in (A) lateral and (B) medial views. Arrow indicates tendon fragment leading to subcutaneous layer of connective tissue (cut). Abbreviations: AM, adductor mandibulae; BPM, buccopalatal membrane; IA, intersegmental aponeurosis.