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Wednesday, February 7th, 2024
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| 3:54a | [Paleontology • 2024] Paratraversodon franciscaensis • Skull Anatomy and Paleoneurology of A New traversodontid (Therapsida: Cynodontia) from the Middle-Late Triassic of Brazil
Abstract Traversodontidae, a clade of gomphodont cynodonts, thrived during the Middle and Late Triassic, displaying a wide geographical distribution. During fieldwork in 2009, a new specimen was discovered in Ladinian/early Carnian stratigraphic layers in southern Brazil. Here, we describe this specimen and propose a new taxon closely related to Traversodon stahleckeri (Traversodontinae) but displaying a unique combination of traits (e.g., presence of a poorly developed suborbital process, mesiodistal length of the paracanine fossa similar to the length of the canine, short diastema between the fourth incisor and the upper canine, and coronoid process not entirely covering the distalmost lower postcanine). Furthermore, the endocranial anatomy of the new taxon was examined. The reconstruction of the cranial endocast revealed paleoneurological features consistent with non-Gomphodontosuchinae traversodontids. These features include the presence of a pineal body (but the absence of an open parietal foramen). These recent findings contribute significantly to our understanding of the evolutionary history and cranial anatomy of Middle-Late Triassic traversodontids, shedding light on the diversity and adaptations of non-mammaliaform cynodonts. Keywords: Dinodontosaurus Assemblage Zone, Ladinian/Carnian, phylogeny, Traversodontidae    Paratraversodon franciscaensis Leonardo Kerber, Lívia Roese-Miron, Thais G. M. Medina, Lúcio da Roberto-da-Silva, Sérgio F. Cabreira and Flávio A. Pretto. 2024. Skull Anatomy and Paleoneurology of A New traversodontid from the Middle-Late Triassic of Brazil. The Anatomical Record. DOI: 10.1002/ar.25385  | ||||||
| 9:49a | [PaleoIchthyology • 2024] Troglocladodus trimblei & Glikmanius careforum • New ctenacanth Sharks (Chondrichthyes: Elasmobranchii: Ctenacanthiformes) from the Middle to Late Mississippian of Kentucky and Alabama, USA
ABSTRACT Two new ctenacanthiform sharks representing two families, Ctenacanthidae and Heslerodidae, have been identified from the Middle to Late Mississippian marine sediments from Mammoth Cave National Park, Kentucky, and two Late Mississippian marine horizons in northern Alabama. The ctenacanthid, Troglocladodus trimblei, gen. et sp. nov., is known from isolated teeth from the Middle Mississippian St. Louis Formation and Ste. Genevieve Formation of Mammoth Cave and the Late Mississippian Bangor Limestone of northern Alabama. Troglocladodus gen. nov. is characterized by broad median cusps, pronounced longitudinal cristae, multiple intermediate cusps, and labiolingually shortened tooth bases. The heslerodid, Glikmanius careforum sp. nov., is known from isolated teeth and visceral arches from the Middle Mississippian St. Louis Formation and Ste. Genevieve Formation and the Late Mississippian Haney Formation, a Hartselle Sandstone-equivalent shale interval, and Bangor Limestone. Glikmanius careforum sp. nov. has proportionately distinct teeth among species of Glikmanius, with more robust and shorter cusps. The palatoquadrate of G. careforum has a short palatine ramus, otic process that is dorsoventrally deep and less expanded antero-posteriorly similar to Heslerodus and Dracopristis, and an elongated quadrate process like Heslerodus. The Meckel’s cartilage is less dorsoventrally deep than Dracopristis. These two new ctenacanth taxa add important information on the diversity of Ctenacanthiformes suggesting three major lineages within the order. Ctenacanths have a rich fossil history from the Late Devonian to the Middle Permian evolving a variety of tooth types and small to large body sizes. Troglocladodus trimblei gen. et sp. nov. Glikmanius careforum sp. nov.
John-Paul M. Hodnett, Rickard Toomey, H. Chase Egli, Gabe Ward, John R. Wood, Rickard Olson, Kelli Tolleson, Justin S. Tweet and Vincent L. Santucci. 2024. New ctenacanth Sharks (Chondrichthyes; Elasmobranchii; Ctenacanthiformes) from the Middle to Late Mississippian of Kentucky and Alabama. Journal of Vertebrate Paleontology. e2292599 | DOI: 10.1080/02724634.2023.2292599 Two new species of ancient sharks identified through research at Mammoth Cave National Park
A focused search for ancient Mississippian Subperiod marine vertebrates during a paleontological resource inventory of Mammoth Cave National Park, Kentucky, has yielded a wealth of new fossil data, previously unrecognized at this park. To date, we have identified marine vertebrate fossils from four primary horizons at the park, two of which are the first records of marine vertebrate fossils occurring in those horizons. Mammoth Cave sites have produced more than 70 species of ancient fish, about 90% representing cartilaginous fishes (sharks and kin), including several new species. The paleontological resource inventory of Mammoth Cave demonstrates that this park is an important resource for providing data on how fish assemblages changed during the formation of the super-continent Pangea. The inventory data also can help correct antiquated information on fossil sharks found in the region (in some cases not updated since their publication in the late 19th century). Hodnett, John-Paul M.; Toomey, Rickard; Olson, Rickard; Tolleson, Kelli; Boldon, Richard; Wood, Jack; Tweet, Justin S. and Santucci, Vincent L. 2024. Sharks in the Dark: Paleontological resource inventory reveals multiple successive Mississippian Subperiod cartilaginous fish (Chondrichthyes) assemblages within Mammoth Cave National Park, Kentucky. Parks Stewardship Forum. 40(1). DOI: 10.5070/P540162921 escholarship.org/uc/item/9rz2v701  |
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