60 research outputs found

    REDESCRIPTION OF ‘PERLEIDUS’ (OSTEICHTHYES, ACTINOPTERYGII) FROM THE EARLY TRIASSIC OF NORTHWESTERN MADAGASCAR

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    The revision of the material from the Lower Triassic fossil-bearing-nodule levels from northwestern Madagascar supports the assumption that the genus Perleidus De Alessandri, 1910 is not present in the Early Triassic. In the past, the presence of this genus has been reported in the Early Triassic of Angola, Canada, China, Greenland, Madagascar and Spitsbergen. More recently, it has been pointed out that these taxa may not be ascribed to Perleidus owing to several anatomical differences. The morphometric, meristic and morphological analyses revealed a remarkable ontogenetic and individual intraspecific variation among dozens of specimens from the lower Triassic of Ankitokazo basin, northwestern Madagascar and allowed to consider the two Malagasyan species P. madagascariensis Piveteau, 1934, and P. piveteaui Lehman, 1952, as a single one and to ascribe it to the new genus Teffichthys. This new genus exhibits a unique combination of features, mainly in the skull dermal bone pattern and structure of caudal fin, that clearly support its exclusion from Perleidiformes. We also suggest to extend the use of Teffichthys for the other Early Triassic ‘Perleidus’ species except those from southern China

    EOCENE RHAMPHOSIDAE (TELEOSTEI: SYNGNATHIFORMES) FROM THE BOLCA LAGERSTÄTTE, ITALY

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    The Rhamphosidae is an extinct family of syngnathiform fishes from the lower Eocene deposits of Europe, primarily known from specimens derived from the Ypresian Konservat-Lagerstätte of Bolca (Verona province, Italy). A descriptive analysis of 28 specimens of Rhamphosus from Bolca revealed the existence of six species, showing a greater taxonomic diversity compared to the previous scenario of only two species (the type species Rhamphosus rastrum and Rhamphosus biserratus). Four new species are established herein: Rhamphosus bloti n. sp., characterized by a peculiar and unique rostrum with a discoid shape; Rhamphosus brevirostris n. sp., which exhibits a moderately large size associated with a relatively short rostrum; Rhamphosus longispinatus n. sp., characterized by having the longest dorsal-fin spine and rostrum of all the Rhamphosus species; Rhamphosus tubulirostris n. sp., which shows a peculiar slim rostrum, long-based dorsal and anal fins, and a unique squamation characterized by the presence of numerous bucklers. The species from Bolca are also compared to the only other known Rhamphosus species, Rhamphosus rosenkrantzi, from the Fur Formation, Denmark. A number of morphological features support the assignment of the Rhamphosidae to the syngnathiform clade Dactylopteroidei, together with the extant families Dactylopteridae and Pegasidae, representing the sister group to the Pegasidae

    First report of Eocene gadiform fishes from the Trans-Urals (Sverdlovsk and Tyumen regions, Russia)

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    AbstractThe recent 2014–2017 controlled excavations carried out in quarries of Sverdlovsk and Tyumen regions, Ural and Western Siberia, are contributing to the knowledge of the middle to late Eocene marine fauna from the Turgay Strait, mainly composed of invertebrates and cartilaginous and bony fishes. Here we present a preliminary report of the bony fishes collected during the campaigns carried out in two Eocene Trans-Urals localities. The sediments of these localities were deposited in a large epicontinental marine basin during the middle to late Eocene, when the Turgay Strait connected the Arctic waters to the North and the Peritethys to the South. Most of the bony fish material examined can be assigned to codfishes (Gadiformes) according to morphological comparison with living and fossil taxa. In particular, nearly complete three-dimensionally preserved lower jaws are confidently assigned to the Merlucciidae, whereas isolated vertebrae and bones are referred to as Gadiformes incertae sedis. This report documents the easternmost occurrence of this group of fishes in the northern hemisphere during the early phases of their radiation, revealing their presence into the Turgay Strait before its closure
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