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The sixgill stingray has a bulky, flabby body with a rounded pectoral fin disc that is longer than wide. The triangular snout is much longer in adults than in juveniles (making up almost two-fifths of the disc length), and is filled with a clear gelatinous material; because of this, the snout of a dead specimen can shrink significantly when exposed to air or preservatives.
Teeth A Stingray: Hemipristis [9] sp. Temple Member Wadi Hitan Teeth A Hemigaleid: Hexanchus [9] sp. Temple Member Wadi Hitan Teeth A Sixgill shark: Himantura [9] sp. Temple Member Wadi Hitan Teeth A Stingray: Leptocharias [9] sp. Temple Member Wadi Hitan Teeth A Hemigaleid: Lophobatis [9] sp. Temple Member Wadi Hitan Teeth An Eagle ray ...
Family Hexatrygonidae: Sixgill stingray Genus Hexatrygon. Hexatrygon bickelli (Sixgill stingray) Family Myliobatidae: Eagle rays and manta rays. Genus Aetobatus. Aetobatus flagellum (Longheaded eagle ray) Aetobatus narinari (Spotted eagle ray) Aetobatus narutobiei (Naru eagle ray) Aetobatus ocellatus (Ocellated eagle ray) Genus Aetomylaeus ...
The oldest known stingray taxon is "Dasyatis" speetonensis from the Hauterivian of England, whose teeth most closely resemble that of the extant sixgill stingray (Hexatrygon). Although stingray teeth are rare on sea bottoms compared to the similar shark teeth, scuba divers searching for the latter do encounter the teeth of stingrays. [6] [8]
New, permanent teeth grow in the jaws, usually under or just behind the old tooth, from stem cells in the dental lamina. [5] Young animals typically have a full set of teeth when they hatch; there is no tooth change in the egg. Within days, tooth replacement begins, usually in the back of the jaw continuing forward like a wave.
Batomorphi is a clade of cartilaginous fishes, commonly known as rays, this taxon is also known as the superorder Batoidea, but the 5th edition of Fishes of the World classifies it as the division Batomorphi. [2]
The mouth cone ("everted pharynx") of a possible new species of Meiopriapulus, a marine worm in the Priapulida, bears pharyngeal teeth. [5] Fossils of the Yunnanozoon and Haikouella possess pharyngeal teeth. The lower pharyngeal bones of cichlids also carry specialized teeth which augment their normal mandibular teeth in the breakdown of food.
A study on the anatomy and affinities of Lasanius is published by Reeves et al. (2023), who interpret this vertebrate as a stem-cyclostome. [9]Dearden et al. (2023) describe the cranial anatomy of Eriptychius americanus, provide evidence of the presence of a symmetrical set of cartilages interpreted as the preorbital neurocranium, and report that the studied cartilages filled out the head and ...