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Donald Davesne


Donald Davesne

My PhD project is focused on the very large-scale phylogeny of the acanthomorph teleosts, with complementary approaches of comparative anatomy – including fossil data – and molecular phylogenetics.

The oldest acanthomorph fossils are Cretaceous in age; some of them have been thoroughly described (e.g. Gayet, 1980; Patterson, 1964, 1993), but have been the subject of only a few phylogenetic analyses (e.g. Otero & Gayet, 1996). In the first part of my PhD project, I'll build an anatomical dataset including some enigmatic fossils, in order to obtain the first phylogeny of the Cretaceous acanthomorphs. The results are expected to bring new perspectives on the interrelationships of this large group as a whole, which are currently in a lack of consensus even with molecular data (cf. Miya et al. 2005; Li et al. 2009). I obtained promising preliminary results on the identification of new morphological synapomorphies for the Acanthomorpha (that is, the characters that are unique to this group). The morphology-based phylogenies including fossils will then be discussed in the regard of new molecular phylogenies, which will include taxa previously neglected by the team (Lampriformes, Polymixiiformes and non-acanthomorphs such as Myctophiformes).

In the second part of my project, I will focus on the former "paracanthopterygians", for example Gadiformes (cods), Percopsiformes (trout-perches) and Lophiiformes (anglerfishes). Current molecular phylogenies are agreeing on the non-existence of this group, suggesting alternatively Gadiformes/Zeiformes (dories) and Lophiiformes/Tetraodontiformes (pufferfishes) clades. My main objective is to test these new interrelationships with anatomical data from key extant and fossil taxa – including some of the oldest acanthomorphs on record.

References:

Gayet, M. 1980. Contribution a l’étude anatomique et systématique des poissons cénomamiens du Liban, anciennement placés dans les acanthoptérygiens. Mémoires du Muséum national d’Histoire naturelle, Série C, Sciences de la Terre 44.

Li, B., Dettaï, A., Cruaud, C., Couloux, A., Desoutter-Meniger, M. and Lecointre, G. 2009. RNF213, a new nuclear marker for acanthomorph phylogeny. Molecular Phylogenetics and Evolution 50 (2): 345–363.

Miya, M., Satoh, T. P. and Nishida, M. 2005. The phylogenetic position of toadfishes (order Batrachoidiformes) in the higher ray-finned fish as inferred from partitioned Bayesian analysis of 102 whole mitochondrial genome sequences. Biological Journal of the Linnean Society 85 (3): 289–306.

Otero, O. and Gayet, M. 1996. Anatomy and phylogeny of the Aipichthyoidea nov. of the Cenomanian Tethys and their place in the Acanthomorpha (Teleostei). Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen 202 (3): 313–344.

Patterson, C. 1964. A review of Mesozoic acanthopterygian fishes, with special reference to those of the English Chalk. Philosophical Transactions of the Royal Society of London. Series B. Biological Sciences 247 (739): 213–482.

Patterson, C. 1993. An overview of the early fossil record of acanthomorphs. Bulletin of Marine Science 52 (1): 29–59.