Abstract
(Englisch)
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Recent notopterids (featherbacks or knife fishes) are fresh or brackish water fishes of Western Africa, India and South East Asia. They form a small monophyletic group of five species of highly derived osteoglossomorphs. The fossils record of notopterids was very poor: one skeletal occurrence of Notopterus sp. from the Late Paleocene of Sumatra and one otolith occurrence from the ?Paleocene of the Intertrappean of the Deccan, India. The stratigraphical and geographical ranges of the family were distinctly enlarged with the description of a notopterid, Palaeonotopterus greenwoodi, based on a single incomplete braincase from the late Albian or early Cenomanian of the Kem Kem beds, Moorocco, by Forey (1997). Then, another very similar specimen from the Kem Kem beds was described by Taverne & Maisey (1998). New material was recently obtained by The Natural History Museum, London, and by the Musée des Dinosaures d'Espéraza, France. These specimens are more complete and provide new information about the osteology and phylogenetic relationships of P. greenwoodi.
The full description and illustrations of three specimens of Palaeonotopterus are carried out. The comparison with Recent specimens of Osteoglossomorpha (Hiodon alosoides, Heterotis niloticus, Osteoglossum bicirrhosum, Notopterus notopterus, Petrocephalus bane, Mormyrops deliciosus,…) leads us to re-interpret anatomical structure, to re-defined several synapomorphies and to discuss the polarity of some characters.
- An autapomorphy of P. greenwoodi observed on the new specimens is a large and ellipsoidal tooth plate formed by the parasphenoid.
- A supraorbital branch of the otic sensory canal, present in P. greenwoodi, was regarded as a synapomorphy of notopterids. Examination of primitive mormyrids, the sister group of notopterids, show that this character is present (Petrocephalus), and thus primitive for the notopteroidei. The cephalic sensory canals pattern in osteoglossomorphs is re-interpret.
- The brain cavity of P. greenwoodi is well preserved and shows that the inner ear display a primitive structure. The condition differs from either the condition observed in notopterids or the condition observed in mormyrids.
- The trigemino-facialis chamber of P. greenwoodi shows a mixture of primitive conditions for teleosts (participation of the prootic bone) and apomorphic conditions present in mormyrids (suture between parasphenoid and autosphenotic).
A cladistic analysis of these characters and others indicate that P. greenwoodi is likely a notopterid as previously proposed but still retains several primitive characters. The monophyly of Notopteroidei is reinforced.
Isolated toothplates from the Upper Cretaceous of England attributed to Plethodus probably belong to a close relative of P. greenwoodi. Two skulls referred to Plethodus by Woodward (1901) are likely not a Notopteroid.
This work will be published in the Zoological Journal of the Linnean Society.
FOREY, P. L. (1997). 'A Cretaceous notopterid (Pisces: Osteoglossomorpha) from Morocco.' South African Journal of Science 93: 564-569.
TAVERNE, L. MAISEY, J. G. (1999). 'A Notopterid skull (Teleostei, Osteoglossomorpha) from the Continental Early Cretaceous of Southern Morocco.' American Museum Novitates 3260: 12 p.
WOODWARD, A. S. (1901). 'Catalogue of the Fossil Fishes in the British Museum (Natural History). Part IV.' : 636.
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