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Friday, November 1st, 2024
| Time | Event | ||||||||
| 9:12a | [PaleoIchthyology • 2024] Ngamugawi wirngarri • A Late Devonian coelacanth reconfigures Actinistian Phylogeny, Disparity, and Evolutionary Ddynamics
Abstract The living coelacanth Latimeria (Sarcopterygii: Actinistia) is an iconic, so-called ‘living fossil’ within one of the most apparently morphologically conservative vertebrate groups. We describe a new, 3-D preserved coelacanth from the Late Devonian Gogo Formation in Western Australia. We assemble a comprehensive analysis of the group to assess the phylogeny, evolutionary rates, and morphological disparity of all coelacanths. We reveal a major shift in morphological disparity between Devonian and post-Devonian coelacanths. The newly described fossil fish fills a critical transitional stage in coelacanth disparity and evolution. Since the mid-Cretaceous, discrete character changes (representing major morphological innovations) have essentially ceased, while meristic and continuous characters have continued to evolve within coelacanths. Considering a range of putative environmental drivers, tectonic activity best explains variation in the rates of coelacanth evolution.  
Systematic palaeontology Osteichthyes Huxley 1880 Sarcopterygii Romer 1955 Actinistia Cope 1871 Ngamugawi wirngarri gen. et sp. nov. Diagnosis: Ngamugawi wirngarri gen. et sp. nov. is distinguished from all other coelacanths by the following apomorphies: jugal canal with prominent branches; large sensory pore openings between supraorbitals and parietals; teeth on parasymphysial tooth plate, but not on the dentary; prearticular and/or coronoid teeth rounded; cleithra and extracleithra with broad triangular anteroventral overlap for clavicle bearing a large ventral foramen; and scales with long ornamental ridges extending beyond the posterior margin of the base (Figs. 1, 2, Supplementary Fig. 1). Locality and horizon: Canning Basin, in northern Western Australia, circa 100 km southeast of Fitzroy Crossing; Gogo Formation, early Frasnian, Late Devonian (~384–382 Ma). The holotype was found between Stromatoporoid Camp and Longs Well, the paratype was found in Paddys Valley. Etymology: Generic name meaning “ancient fish” in Gooniyandi/Guniyandi, language of the First Nations people from Country around Fitzroy Crossing in the Kimberley region of Western Australia. Specific name is given in honour of respected Gooniyandi elder and ancestor Wirngarri, who lived in the Emanuel Range. Generic and specific names were both provided to Prof. John Long in September 2023, who has a longstanding and ongoing relationship with the community, with permissions to use the language granted by elder Rosemary Nuggett, on behalf of the Gooniyandi people of the Mimbi community.
Alice M. Clement, Richard Cloutier, Michael S. Y. Lee, Benedict King, Olivia Vanhaesebroucke, Corey J. A. Bradshaw, Hugo Dutel, Kate Trinajstic and John A. Long. 2024. A Late Devonian coelacanth reconfigures Actinistian Phylogeny, Disparity, and Evolutionary Ddynamics. Nature Communications. 15: 7529. DOI: doi.org/10.1038/s41467-024-51238-4   | ||||||||
| 5:13p | [PaleoMammalogy • 2024] Prosantorhinus yei • The First record of the Genus Prosantorhinus (Perissodactyla: Rhinocerotidae) of East Asia
Abstract Prosantorhinus is a genus of small extinct teleoceratine rhinoceroses with shortened limb bones, widely distributed in Europe. However, the Asian evolution of the teleoceratine Prosantorhinus has remained unclear because of a scarcity of fossil records of the genus. Here, we report the first record of Prosantorhinus in East Asia from the Middle Miocene of Tongxin, Ningxia. The new specimen is characterized by a concave dorsal skull profile and elevated nasals; short and stout nasal bones with drooping margins on both sides; the thickened, enlarged, and roughened nasal extremity supporting a small horn; the semi-molarized upper premolars with a lingual bridge between the protocone and hypocone; the metaloph constriction present on P2–4; the protocone equal to the hypocone on P2; the crista present on P3; and the cement on the cheek teeth developed. With all the morphological evidence considered, we establish a new species, Prosantorhinus yei sp. nov.. A phylogenetic analysis based on 282 morphological characters scored for 36 taxa reveals that Prosantorhinus yei sp. nov. is a relatively derived taxon in the genus. We hypothesize that Prosantorhinus yei sp. nov. lived in relatively moist environments. Prosantorhinus, Middle Miocene, phylogeny, palaeoecology, China  Prosantorhinus yei sp. nov. Danhui Sun, Tao Deng and Shiqi Wang. 2024. The First record of the Genus Prosantorhinus (Perissodactyla: Rhinocerotidae) of East Asia. Zoological Journal of the Linnean Society. 202(2); zlad183, DOI: doi.org/10.1093/zoolinnean/zlad183 |
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