Pantodontidae, Peters, 1876

Hilton, Eric J. & Lavoué, Sébastien, 2018, A review of the systematic biology of fossil and living bony-tongue fishes, Osteoglossomorpha (Actinopterygii: Teleostei), Neotropical Ichthyology 16 (3), pp. 1-35 : 11-12

Pantodontidae .

A single species comprising genetically differentiated allopatric populations, Pantodon buchholzi , the African butterfly fish, is classified in the family Pantodontidae ( Nelson et al., 2016), although it is frequently included within the family Osteoglossidae (e.g., Taverne, 1979; Li, Wilson, 1996a; Hilton, 2003). This is a relatively small fish, with a strongly upturned mouth, flattened head, short dorsal and anal fins positioned far back on its body, a rounded caudal fin, large wing-like pectoral fins, and pelvic fins with an elongate fin rays ( Fig. 12 ). The head and pectoral fin has a superficial similarity to that of osteoglossines. Despite its similarity in some respects (e.g., infraorbital bones) to Osteoglossinae , Nelson (1969: 25) observed that “the systematic position of Pantodon consequently is obscure.” This remains to be the case (see below). Part of the issue with the systematic placement of Pantodon is that it is a highly derived taxon, with numerous autapomorphies as well as significant character conflict with other osteoglossomorphs. For instance, the absence of a symplectic is shared with Mormyroidea, whereas the absence of an autopalatine is shared with Osteoglossidae ( Moritz, Britz, 2005). However, unlike those of osteoglossid conditions, the scales of Pantodon lack reticulations (e.g., Hilton, 2003: fig. 39) and Pantodon has two gonads (versus one) ( Britz, 2004).

The skeletal anatomy of Pantodon has been described and illustrated by Taverne (1978), and portions of its skeleton was illustrated and described by Hilton (2003) and Hilton, Britz (2010). In a study of its development, Moritz, Britz (2005) showed that the single dermal bone of the palatoquadrate in the adult of Pantodon is an ontogenetic fusion of the dermopalatine and ectopterygoid. They further conclude that the basipterygoid articulation found in Pantodon and Osteoglossidae is structurally homologous to that found in non-teleosts and a basal clupeomorph, and therefore is a character at a broader level of phylogeny than uniting a subgroup of osteoglossomorphs (e.g., Greenwood et al., 1966; Lauder, Liem, 1983; Arratia, Schultze, 1991).

Figures

Fig. 12. Pantodontidae. Pantodon buchholzi (CU 87447). Scale bar = 2 cm.