ACTINOPTERYGII Cope, 1887

Ostrowski, Summer A., 2021, Late Cretaceous Elopomorpha (Actinopterygii: Teleostei) from the Mahajanga Basin of Madagascar and impacts on paleobiogeography, Palaeontologia Electronica (a 31) 24 (3), pp. 1-15 : 6

Class ACTINOPTERYGII Cope, 1887 Superorder ELOPOMORPHA Greenwood et al., 1966

Genus indet.

Figure 5

Material. Six vertebrae ( DMNH EPV.136305, DMNH EPV.136306, DMNH EPV.136307, DMNH EPV.136308, UA 11393, UA 11394,)

Occurrence. Berivotra Study Area (Anembalemba Member) and Lac Kinkony Study Area (Lac Kinkony Member).

Description. The elopomorph vertebrae from Madagascar encompass a wide range of morphotypes (Figure 5) and are found across several localities within the Maevarano Formation. These amphicoelous vertebrae range in size from small to large (less than 0.5 cm to over 2.5 cm at their widest point) and qualitative morphology from simple, slightly sub-circular, and thin (Figure 5A, 5C-F) to robust with a highly sigmoidal margin (Figure 5B). These vertebrae are also rostro-caudally flattened (plate-like), exhibit fine parallel fibers around the perimeter from edge to edge (oriented rostro-caudally), and deeper articular pits that accommodate the neural arch (dorsal) are widely spaced from the parapophyseal articular pits. Brinkman and Neuman (2002) noted that this combination of vertebral features are not found outside of Elopomorpha . The ventral side of the vertebrae may bear a shallow indentation to accommodate vasculature. Most of the elopomorph vertebrae from the Maevarano Formation are 1.0 – 1.5 cm at their widest point, and are subcircular. The vertebrae themselves are isolated, surface collected elements and not associated with any tooth plates. Because of the variability in teleost vertebrae within a single individual, we cannot assume a more specific taxonomic identification of these isolated vertebrae. The majority of the large, robust vertebrae occur within the Lac Kinkony Member, which is also more likely to have Paralbula tooth plates, but no official association can be made. No detailed descriptions have noted differences in isolated vertebrae between Paralbula , Egertonia , and Albula .