Exocoetus, Ichthyokentema and Oreochima AMNH 9910

Exocoetus volitans (Linneaus 1758; up to 30cm ) is the extant blue flyingfish, here related to a smaller Jurassic relative, Oreochima. Exocoetus travels in schools or schoals. Sometimes they exit the water to avoid predators. Juveniles have a relatively shorter torso. Hatchlings are slow-moving and tiny. Distinctly flying fish and their relatives have a jaw joint directly below the orbit. The coracoid is larger than the scapula, raising and powering the pectoral fins.

Ichthyokentema purbeckensis (Woodward 1941, originally Pholidophorus purbeckensis Davies 1887, Late Jurassic, 12cm) nests nests at the base of the Oreochima clade close to Pholidophorus.

Oreochima ellioti (Schaeffer 1972, Early Jurassic, Antarctica, 6cm long) was originally considered close to Pholidophorus. The Bean 2021 thesis nested Oreochima close to Wadeichthys. Here the AMMH 9910 specimen nests with the flying fish, Exocoetus.

Oreochima ellioti (Schaeffer 1972, Early Jurassic, Antarctica, 6cm long, AMNH 9911, 9912) was originally considered close to Pholidophorus, perhaps based on the less than optimal freehand graphic shown here based on several specimens. The maxilla should be straight and a postparietal was present according to fossil photo data. The Bean thesis nested Oreochima close to Wadeichthys.

The 9910 specimen (bottom) nests with the flying flish, Exocoetus.

Bean LB 2021a. The morphological revisions of freshwater fishes from Late Jurassic – Early Cretaceous sites in Australia and other Gondwanan continents leads to new phylogenetic hypotheses of relationships among stem teleosts. U3336714 Research School of Earth Sciences. A thesis submitted for the degree of Doctor of Philosophy of The Australian National University.

Bean LB 2021b. Revision of the Mesozoic freshwater fish clade Archaeomaenidae. Alcheringa: An Australasian Journal of Palaeontology. 45 (2): 217–259.

Davies W 1887. I.—On New Species of Pholidophorus from the Purbeck Beds of Dorsetshire. Geological Magazine. 4 (8): 337–339. Bibcode:1887 doi:10.1017/S0016756800193914. S2CID129013028

Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

Olsen PE 1984. The skull and pectoral girdle of the parasemionotid fish Watsonulus eugnathoides from the Early Triassic Sakamena Group of Madagascar, with comments on the relationships of the holostean fishes. Journal of Vertebrate Paleontology 4(3):481–499.

Piveteau J 1930. C R Acad. Sci. Paris, 191.

Piveteau J 1935. Palkontologie de Madagascar. XXI. Les Poissons du Trias infkrieur. Contribution 2 l’ktude des actinoptkrygiens. Annales de Pal6ontologie 23:8 1-1 80.

Schaeffer B 1972. A Jurassic fish from Antarctica. American Museum Novitates 2495:1–17.

Woodward AS 1941. "VIII.— The Mesozoic Ganoid Fishes of the Genus Pholidophorus Agassiz. Annals and Magazine of Natural History 8 (44): 88–91. doi:10.1080/03745481.1941.9727955.

wiki/Oreochima
wiki/Exocoetus_volitans
wiki/Ichthyokentema