collaborateurs

Luigi Manuelli

Collaborateur externe chez MuséumLab

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  • A dual respiratory and auditory function for the coelacanth lung. Commun Biol 2026 Feb ; 10.1038/s42003-026-09708-6. 10.1038/s42003-026-09708-6.

    résumé

    Since the discovery of Latimeria chalumnae, coelacanths have provided a critical comparative framework for reconstructing ancestral sarcopterygian anatomy. However, the function of several anatomical features in both extant and fossil coelacanths remains unresolved. Among these, the presence of large ossified chambers in the body cavity of fossil coelacanths has remained enigmatic, with different studies proposing respiratory or auditory functions. Here, we examine lung and inner ear anatomy based on new observations from synchrotron phase-contrast microCT scans of two 240-million-year-old latimerioid coelacanths, alongside multiple developmental stages of the extant L. chalumnae. These data, combined with archival histological sections of L. chalumnae and 3D reconstructions of a Devonian coelacanth, suggest that extinct coelacanths possessed an ossified lung capable of transmitting sound pressure to auditory sensory epithelia in the inner ear via a perilymphatic system. We propose that the lung of extinct coelacanths supported both respiratory and auditory functions.

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  • The most detailed anatomical reconstruction of a Mesozoic coelacanth PloS one, 19(11), e0312026. https://doi.org/10.1371/journal.pone.0312026 Format:

    résumé

    Although the split of coelacanths from other sarcopterygians is ancient, around 420 million years ago, the taxic diversity and the morphological disparity of the clade have remained relatively low, with a few exceptions. This supposedly slow evolutionary pace has earned the extant coelacanth Latimeria the nickname "living fossil". This status generated much interest in both extinct and extant coelacanths leading to the production of numerous anatomical studies. However, detailed descriptions of extinct taxa are made difficult due to the quality of the fossil material which generally prevents fine comparisons with the extant Latimeria. Here we describe a new genus and species of coelacanth, Graulia branchiodonta gen. et sp. nov. from the Middle Triassic of Eastern France, based on microtomographical imaging using synchrotron radiation. Through exquisite 3D preservation of the specimens, we reconstructed the skeletal anatomy of this new species at an unprecedented level of detail for an extinct coelacanth, and barely achieved for the extant Latimeria. In particular, we identified a well-developed trilobed ossified lung whose function is still uncertain. The skeletal anatomy of G. branchiodonta displays the general Bauplan of Mesozoic coelacanths and a phylogenetic analysis resolved it as a basal Mawsoniidae, shedding light on the early diversification of one of the two major lineages of Mesozoic coelacanths. However, despite its exquisite preservation, G. branchiodonta carries a weak phylogenetic signal, highlighting that the sudden radiation of coelacanths in the Early and Middle Triassic makes it currently difficult to detect synapomorphies and resolve phylogenetic interrelationships among coelacanths in the aftermath of the great Permo-Triassic biodiversity crisis.

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Thesis title

« Investigating morphological novelty in several taxa of Mesozoic bony fishes. My PhD work is currently focusing on a series of fossil coelacanths with unusual tridimensional preservation, found in Triassic deposits near Saverne (East of France, Alsace), possibly representing a new species. I will also examine a fossil coelacanth with aberrant morphological features, from the Jurassic Solnhofen limestone (Bavaria, Germany). Another research line aims at further unravelling the evolution of the suction disc of a primitive remora (echeneid fish) found in the Oligocene of Engi, Canton Glarus. Classical paleontological tools are integrated with more modern approaches like MicroCT. »

Superviseur: Lionel Cavin