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Showing results for tags 'albertonia'.
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Presumably a slow swimming grazer-detritivore. Alternative combination: Elonichthys cupidineus Lambe, 1916. Taxonomy according to fossilworks.org. Diagnosis for Albertonia according to Schaeffer and Mangus, 1976, pp. 545-548: "A parasemionotid (as defined by Patterson, 1973, pp. 262, 287) specialized in having deeply fusiform body and greatly elongated pectoral fins. Small acuminate marginal teeth present on mobile maxilla and dentary. Suspensorium nearly vertical. Preopercular present; opercular and subopercular subequal. Longest pectoral fm rays about one-half length of body. All fins bordered by fringing fulcra; fin rays distally segmented. Caudal fin hemiheterocercal, weakly cleft, and probably equilobate. Scales rhomboidal, deeper than wide in anterior flank region; posterior border of all scales pectinate.“ Quote from Schaeffer and Mangus, 1976, p. 548: “Albertonia cupidinia . . . is a deeply fusiform fish: the maximum body depth is about one-third of the overall length. The impressively elongated pectoral fins, composed of approximately 21 rays, are equal to about one-half of the total body length. The pelvic fins, which are very much smaller and include nine or 10 rays, are situated at the deepest part of the ventral contour. The dorsal fin, composed of about 17 rays, arises in front of the anal, which has approximately 18 rays. The short-lobed hemiheterocercal caudal fin is composed of about 30 principal rays and is externally homocercal. The scales are rhombic with serrated posterior borders. There are about 40 scale rows between the cleithrum and the origin of the hypochordal lobe of the caudal fin." Identified by Dr. N. Micklich (Hessisches Landesmuseum Darmstadt - HLMD). Sketch of Albertonia from Anderson and Woods, 2013, p. 325. References: Lambe, L. M. (1916): Ganoid fishes from near Banff, Alberta. Proceedings and Transactions of the Royal Society of Canada, Series 3 10:35-44. Schaffer, B. and Mangus, M. (1976): An Early Triassic fish assemblage from British Columbia. Bulletin of the American Museum of Natural History 156(5): 515-564. Anderson, K. and Woods, A. D. (2013): Taphonomy of Early Triassic fish fossils of the Vega-Phroso Siltstone Member of the Sulphur Mountain Formation near Wapiti Lake, British Columbia, Canada. Journal of Palaeogeography 2(4):321-343.
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Taxonomy from Fossilworks.org. Due to its enormous pectoral fins, Icarealcyon malagasium was described by Beltan as a "poisson volant" - a "flying fish" - in the family Semionotidae (not related to what is now known as "flying fish" - these are Exocoetidae in the order Beloniformes). You would expect flying fish to be fast swimmers - the rather thickset appearance of Icarealcyon more likely hints to slow swimmers with relatively high maneuverability (comparable to Albertonia from British Columbia). Icarealcyon was described by Beltan on the basis of poor material - in all three specimens only the body without head was preserved. Icarealcyon is probably closely related to Albertonia, or possibly even a synonym. Line drawing from Beltan 1984, p. 78: References: L. Beltan. 1984. A propos d'un poisson volant biplan d l'Eotrias du NW de Madagascar: Icarealcyon malagasium Beltan. Annales de la Société Géologique du Nord 103:75-82
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