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Tuesday, March 11th, 2025
| Time | Event | ||||||
| 4:18p | [PaleoIchthyology • 2025] Clavusodens mcginnisi • Obruchevodid petalodonts (Chondrichthyes: Petalodontiformes; Obruchevodidae) from the Middle Mississippian (Viséan) Joppa Member of the Ste. Genevieve Formation at Mammoth Cave National Park, Kentucky, U.S
Abstract Obruchevodid petalodonts are rare small chondrichthyans known from nearly complete to partial skeletons from the Upper Mississippian (Serpukhovian) Bear Gulch Limestone of central Montana and isolated teeth from the Upper Mississippian Bangor Limestone of northern Alabama. New records of obruchevodid petalodonts are presented here from the Middle Mississippian (Viséan) Joppa Member of the Ste. Genevieve Formation at Mammoth Cave National Park, Kentucky. Obruchevodids are here represented by multiple teeth of a new taxon, Clavusodens mcginnisi n. gen. n. sp., and a single tooth referred to ?Netsepoye sp. Clavusodens mcginnisi n. gen. n. sp. is characterized by teeth with pointed mesiodistal and lingual margins and more robust chisel-like cusps on the anterolateral and distolateral teeth. The suggestion that obruchevodid petalodonts evolved to inhabit complex reef-like environments and other nearshore habitats with a feeding ecology analogous to extant triggerfish is explored and discussed.
Systematic paleontology Class Chondrichthyes Huxley, 1880 Subclass Euchondrocephali Lund and Grogan, Reference Lund and Grogan, 1997 Order Petalodontiformes Patterson, 1965 Family Obruchevodidae Lund, Grogan, and Fath, 2014 Genus Clavusodens new genus Occurrence: Mammoth Cave National Park, Kentucky, Middle Mississippian (upper Viséan) Joppa Member, Ste. Genevieve Formation. Etymology: Latin, clavus (nail), and dents (tooth); in recognition of the nail-like shape of the distal lateral teeth. Clavusodens mcginnisi new species Etymology: In honor of retired National Park Service superintendent and naturalist David McGinnis for his leadership in paleontological resource stewardship during his 39-year career beginning at Mammoth Cave National Park. John-Paul M. Hodnett, H. Chase Egli, Rickard Toomey, Rickard Olson, Kelli Tolleson, Richard Boldon, Justin S. Tweet and Vincent L. Santucci. 2025. Obruchevodid petalodonts (Chondrichthyes, Petalodontiformes, Obruchevodidae) from the Middle Mississippian (Viséan) Joppa Member of the Ste. Genevieve Formation at Mammoth Cave National Park, Kentucky U.S.A. Journal of Paleontology. First View. DOI: doi.org/10.1017/jpa.2024.40 Fossil Research Identifies New Shark Species at Mammoth Cave National Park The small shark named Clavusodens mcginnisi, or “McGinnis’ nail tooth,” only measured 3-4 inches in length.  Non-technical Summary: New records of two species of obruchevodid petalodont chondrichthyans are described from the Middle Mississippian Joppa Member of the Ste. Genevieve Formation from Mammoth Cave National Park, Kentucky. The two species are Clavusodens mcginnisi new genus new species, which had more robust crushing-type teeth for its kind, and ?Netsepoye sp., which is based on a partial tooth. These two records represent the oldest known obruchevodid petalodonts, which previously were known from younger Mississippian-age rocks in Montana and Alabama. Obruchevodid petalodonts were among the most specialized cartilaginous fishes during the Mississippian, potentially adapted to live in complex reef and reef-like habitats. | ||||||
| 11:59p | [PaleoOrnithology • 2024] Paakniwatavis grandei • A new Paleogene fossil and a new dataset for Waterfowl (Aves: Anseriformes) clarify phylogeny, ecological evolution, and Avian Evolution at the K-Pg Boundary
Abstract Despite making up one of the most ecologically diverse groups of living birds, comprising soaring, diving and giant flightless taxa, the evolutionary relationships and ecological evolution of Anseriformes (waterfowl) remain unresolved. Although Anseriformes have a comparatively rich, global Cretaceous and Paleogene fossil record, morphological datasets for this group that include extinct taxa report conflicting relationships for all known extinct taxa. Correct placement of extinct taxa is necessary to understand whether ancestral anseriform feeding ecology was more terrestrial or one of a set of diverse aquatic ecologies and to better understand avian evolution around the K-T boundary. Here, we present a new morphological dataset for Anseriformes that includes more extant and extinct taxa than any previous anseriform-focused dataset and describe a new anseriform species from the early Eocene Green River Formation of North America. The new taxon has a mediolaterally narrow bill which is rarely found in previously described anseriform fossils. The matrix created to assess the placement of this taxon comprises 41 taxa and 719 discrete morphological characters describing skeletal morphology, musculature, syringeal morphology, ecology, and behavior. We additionally combine the morphological dataset with published sequences using Bayesian methods and perform ancestral state reconstruction for select morphological, ecological and behavioral characters. We recover the new Eocene taxon as the sister taxon to (Anseranatidae+Anatidae) across all analyses, and find that the new taxon represents a novel ecology within known Anseriformes and the Green River taxa. Results provide insight into avian evolution during and following the K-Pg mass extinction and indicate that Anseriformes were likely ancestrally aquatic herbivores with rhamphothecal lamellae..
Systematic paleontology AVES Linnaeus, 1758 NEOGNATHAE Pycraft, 1900 ANSERIFORMES Wagler, 1831 Paakniwatavis grandei, gen. et sp. nov. Etymology: Paakniwatavis references Paakniwat, used by the Shoshoni tribe indigenous to the region of the recovery site and means “Water Spirit”. The Water Spirits are dangerous supernatural beings that lure people to their death with child-like cries. The name references the aquatic ecology of this taxon. The species honors Dr. Lance Grande, who collected the holotype specimen, in recognition of his leading research on the faunas of the Green River Formation.  Grace Musser and Julia A. Clarke. 2024. A new Paleogene fossil and a new dataset for waterfowl (Aves: Anseriformes) clarify phylogeny, ecological evolution, and avian evolution at the K-Pg Boundary. PLoS ONE. 19(7): e0278737. DOI: doi.org/10.1371/journal.pone.0278737 https://www.biorxiv.org/content/10.1101/2  |
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