[Most Recent Entries] [Calendar View]
Wednesday, October 9th, 2024
| Time | Event | ||||||||||
| 4:07a | [Paleontology • 2024] Platypterygius elsuntuoso • A New Species of Platypterygius (Ichthyosauria: Ophthalmosauridae) from the lower Barremian of Colombia and Assessment of the Species Composition of the Genus
Abstract In this paper, we describe a new ophthalmosaurid specimen found in the lower Barremian beds of the Paja Formation at Villa de Leiva, Boyacá, Colombia. The specimen represents a new species of Platypterygius, P. elsuntuoso sp. nov. defined by three unique features within the genus: a small ventral peg in the anterior ventral border of the extracondylar area of the basioccipital; a supratemporal groove in the quadrate; and a shallow neck at the base of the acellular cementum ring on the teeth root. In support of our taxonomic determination, in this contribution we also assess the species composition of the genus Platypterygius, comparing the known anatomy of the type species P. platydactylus with that of the other species previously assigned to the genus. We found that a great morphological affinity in the forelimb of the species P. americanus, P. australis, P. hercynicus, and P. sachicarum (lower Barremian to lower Cenomanian) with that of the type species (Aptian) is unquestionable and differentiate them from all other ophthalmosaurids. Three new diagnostic features (synapomorphies of the genus) support their inclusion in Platypterygius. Consequently, the genus name “Kyhytysuka”, recently proposed to differentiate P. sachicarum from the genus Platypterygius is here rejected. A careful comparison of the cranial characteristics of Platypterygius specimens preserving associated cranial and fin remains demonstrate that Platypterygius is a genus distinguishable from other ophthalmosaurids not only by a typical forelimb but also by a particular combination of skull features. In this context, the skull morphology of “Simbirskiasaurus” concurs with that defining Platypterygius and its minor differences are not sufficient to support its generic distinction. The morphological comparisons and our phylogenetic analysis show the new species P. elsuntuoso more closely related to the Colombian species P. sachicarum than to other species of Platypterygius. Given that the new species came from the lower Barremian and P. sachicarum came from the upper Barremian, the minor differences in dentition found between the two species suggest a speciation by adaptation to new food sources in the Cretaceous epicontinental sea of Colombia. Keywords: Ophthalmosauridae; Platypterygius; Barremian; Colombia
ICHTHYOSAURIA de Blainville, 1835 OPHTHALMOSAURIDAE Baur, 1887 Platypterygius elsuntuoso sp. nov. Holotype and only known specimen: FCG-CBP-28. A skull lacking the anterior portion of the snout; some disarticulated axial elements, incomplete left coracoid, and a few phalanges. Type locality and horizon: Loma La Cabrera, northwest of Villa de Leiva, Boyacá. Paja Formation, Arcillolitas abigarradas Member, segment A or B of Etayo-Serna (1968a), lower Barremian (Benavides-Cabra et al., 2023) (Fig. 1). Diagnosis: P. elsuntuoso is distinguished from other species of Platypterygius by the following unique features: 1- The anterior ventral border of the extracondylar area of the basioccipital bears a small ventral peg anteroventrally directed (Shared with Plutoniosaurus, Zverkov pers. comm.), which fits into a posteroventral depression found in the basisphenoid; 2- Quadrate with supratemporal groove dorsal to the stapedial foramen (Shared with Plutoniosaurus Zverkov pers. comm.; and Undorosaurus see Zverkov & Efimov, 2019) ; and 3- Root of teeth with a shallow neck at the base of the acellular cementum ring. ... Derivation of name: from “el suntuoso”, Spanish for “the sumptuous”, nickname used by C. B. Padilla, deceased founder of the FCG and CIP, when referring to the specimen. María E. Páramo-Fonseca, Cristian D. Benavides-Cabra and Renzo A. Garavito-Camacho. 2024. A New Species of Platypterygius (Ophthalmosauridae) from the lower Barremian of Colombia and Assessment of the Species Composition of the Genus. Earth Sciences Research Journal. 28(2); DOI: doi.org/10.15446/esrj.v28n2.112332 | ||||||||||
| 5:16a | [Paleontology • 2024] Ardetosaurus viator • A New diplodocine Sauropod from the Morrison Formation, Wyoming, USA
ABSTRACT The Morrison Formation of the western United States is well-known for its high diversity of sauropod dinosaurs. The Howe-Stephens Quarry in northern Wyoming is one of several quarries which has yielded several associated to completely articulated dinosaur specimens, among which a semi-articulated diplodocid specimen, MAB011899, which was excavated in 1993. This diplodocid specimen is represented by posterior cervical, dorsal, sacral, and anterior caudal vertebrae, multiple thoracic ribs, two chevrons, a left coracoid, a left ilium, both pubes and ischia, a left femur, a left tibia, and a left fibula. Through comparative anatomy, we interpret this specimen as a new species of diplodocine sauropod, Ardetosaurus viator gen. et sp. nov. Unambiguous autapomorphies include paired accessory laminae in the spinoprezygapophyseal fossae of posterior cervical and anterior dorsal vertebrae, bifurcating anterior centrodiapophyseal laminae in the anterior dorsal vertebrae, fossae present in the centropostzygapophyseal laminae of the second dorsal vertebra, a low vertebral height/centrum length ratio of the posterior dorsal vertebrae and reduced to absent centroprezygapophyseal laminae in the anterior caudal vertebrae. Local autapomorphic features include single centroprezygapophyseal laminae in the posterior cervical vertebrae and a highly elliptical cross-section of the femoral midshaft. Ardetosaurus viator is the first skeletally mature sauropod specimen described from the Howe-Stephens Quarry. This specimen provides insight into serial variation of vertebral laminae and laminar transitions. Finally, the peculiar morphology of the—often not preserved—first chevron is described in detail, and its possible use in studying sexual dimorphism in sauropods is discussed. Keywords: sauropod; new genus; new species; Morrison Formation; Diplodocinae; Wyoming   
SYSTEMATIC PALEONTOLOGY DINOSAURIA Owen, 1842 SAUROPODA Marsh, 1878 EUSAUROPODA Upchurch, 1995 NEOSAUROPODA Bonaparte, 1986 DIPLODOCOIDEA Marsh, 1884 FLAGELLICAUDATA Harris and Dodson, 2004 DIPLODOCIDAE Marsh, 1884 DIPLODOCINAE Marsh, 1884 ARDETOSAURUS gen. nov. Ardetosaurus viator gen. et sp. nov. Holotype. MAB011899: two cervical vertebrae, 10 dorsal vertebrae, sacrum, five caudal vertebrae, eight dorsal ribs, two chevrons, a left coracoid, a left ilium, both pubes, both ischia, a left femur, a left tibia, and a partial left fibula. Diagnosis. Ardetosaurus viator is diagnosed by the combination of the following autapomorphies: 1) the presence of distinct, paired accessory laminae in the spinoprezygapophyseal fossae (SPRF) in the posterior cervical and anterior dorsal vertebrae, 2) anteroventrally bifurcating anterior centrodiapophyseal laminae (ACDLs) in the anterior dorsal vertebrae, 3) the presence of centropostzygapophyseal lamina fossae (CPOL-f) in the second dorsal vertebra, 4) a vertebral height/centrum length ratio of <2.5 of the posterior dorsal vertebrae, and 5) reduced or absent centroprezygapophyseal laminae (CPRLs) in the anterior-most caudal vertebrae. Ardetosaurus viator differs from all other diplodocines by having unbifurcated CPRLs in the posterior cervical vertebrae and a highly elliptical femoral cross-section. Ardetosaurus viator differs from Amphicoelias Cope, 1878, in lacking the rounded, lateral projections of the neural spine tip and the thin neural spine base in the dorsal vertebrae; from Barosaurus Marsh, 1890, by having tall cervical neural spines, single midline keels, narrower prezygapophyseal rami in the cervical vertebrae, ten dorsal vertebrae, the presence of ... Etymology. ‘Ardeto’ is an inflection of Latin ārdēre, meaning ‘to burn.’ It refers to the history of some of the elements, which were either fully destroyed in a fire, or still show burn scars from the fire. ‘saurus, ’ Latinized form of the Greek σαῦρος (saúros), meaning lizard or reptile. ‘viator’ is Latin for traveler, referring to the journey of the specimen from the USA, via Switzerland and Germany, to the Netherlands. Locality and horizon. Ardetosaurus viator comes from the Howe-Stephens Quarry of northern Wyoming, USA. The quarry is dated, based on magnetostratigraphy and correlation with other sections in the Morrison basin (Maidment and Muxworthy, 2019; Maidment, personal communication, 2022) at 150.44 to 149.21 million years old, placing it in the Kimmeridgian Stage of the Upper Jurassic.
Tom T.P. van der Linden, Emanuel Tschopp, Roland B. Sookias, Jonathan J.W. Wallaard, Femke M. Holwerda, and Anne S. Schulp. 2024. A New diplodocine Sauropod from the Morrison Formation, Wyoming, USA. Palaeontologia Electronica. 27(3): a50. DOI: doi.org/10.26879/1380 palaeo-electronica.org/content/2024/5327-n | ||||||||||
| 7:29a | [PaleoEntomology • 2022] Magicivena sticta, M. elegans & M. antennalis • Early Cretaceous enigmatic Insect Group [Magicivenidae fam. nov.] showing unique Wing Venations and Antennal Sensilla
Abstract A new extinct insect group, Magicivena gen. nov. in Magicivenidae fam. nov., with M. sticta sp. nov. (type species), M. elegans sp. nov., M. antennalis sp. nov. and M. sp., is reported as Insecta incertae ordinis based on four specimens from the Lower Cretaceous Yixian Formation of north-eastern China. Magicivenidae are characterized by special antennal structures, such as each flagellomere having two lateral transverse rows of setiferous pits, and forewing venations such as a very short subcostal anterior (Sc), the radial posterior (RS) apparently lost, a weak cubital posterior (CuP), and a single cross-vein crossing the CuP and joining the cubital anterior (CuA) to the first anal vein, all of which differ from those of any other fossil or extant insect taxa documented hitherto. According to the characters forewing with multibranched CuA, hind wing with several long anal veins, and segmented cerci, Magicivenidae should belong to Polyneoptera. The light constitution of a good flier, similar structure of the pterostigma in the hind wing, and transverse furrow on the pronotum all suggest the parallel evolution of Magicivenidae and a dictyopterid family, Alienopteridae. However, the advanced bimotory and loss of an identifiable RS make the possible affinity of Magicivenidae with Alienopteridae problematic, as the latter possess utmost posteromotory and a distinct RS. The antennae of Magicivenidae with their sophisticated sensory apparatus suggest that the four known specimens of Magicivena described here are all males; females are still to be discovered. This new finding enriches the known diversity of Cretaceous insect groups. Keywords: Magicivena, Magicivenidae, flagellomere, flight, Yixian Formation, Alienopteridae  Magicivenidae fam. nov. Magicivena gen. nov. M. sticta sp. nov. (type species), M. elegans sp. nov., M. antennalis sp. nov.  Hongru Yang, Chungkun Shih, Alexandr P. Rasnitsyn, Dong Ren and Taiping Gao. 2022. Early Cretaceous enigmatic Insect Group showing unique Wing Venations and Antennal Sensilla. Papers in Palaeontology. DOI: 10.1002/spp2.1402 twitter.com/Dean_R_Lomax/status/1445391039439818764 | ||||||||||
| 11:03a | [Paleontology • 2024] Validity of Myobradypterygius hauthali von Huene, 1927 (Ichthyosauria: Ophthalmosauria) from the Early Cretaceous of Chile and Argentina
Abstract Early Cretaceous ichthyosaurs were globally distributed pelagic marine reptiles, but many remains are fragmentary, creating a Northern Hemisphere diversity bias. A rich Hauterivian locality near the Tyndall Glacier inside Torres del Paine National Park in southern Chile yields important new data regarding ichthyosaurian diversity along the Pacific margin of Gondwana. These new data will contribute to clarifying questions regarding ichthyosaur taxonomy and the palaeobiogeographical relationships between the southern Gondwanan and Northern Hemisphere ichthyosaur groups during the Early Cretaceous. Here, we describe three new ichthyosaur specimens from this locality. Two of them are referred to Myobradypterygius hauthali, expanding the distribution of this species from the Barremian of Argentina to the Hauterivian of the Chilean Patagonia. This material shows that M. hauthali differs from Platypterygius platydactylus in forefin construction and scapular morphology, supporting its classification as a separate genus within Platypterygiinae. The third specimen is a large-bodied indeterminate ophthalmosaurine ichthyosaur. This record represents the southernmost record of Ophthalmosaurinae and the first occurrence of this group from the Cretaceous of the Southern Hemisphere. These discoveries show that ophthalmosaurines and platypterygiines continued to occur sympatrically in southernmost Gondwana during the Early Cretaceous, expanding the pattern documented in Europe to the Pacific region. Ichthyosauria, Early Cretaceous, Gondwana, Patagonia    Judith Pardo-Pérez, Patricio Zambrano, Matthew Malkowski, Dean Lomax, Rodrigo Villa-Martínez, Wolfgang Stinnesbeck, Eberhard Frey, Francisca Scapini, Cristina Gascó and Erin E Maxwell. 2024. Validity of Myobradypterygius hauthali von Huene, 1927 (Ichthyosauria: Ophthalmosauria) from the Early Cretaceous of Chile and Argentina. Zoological Journal of the Linnean Society. 202(2); zlae106. DOI: doi.org/10.1093/zoolinnean/zlae106 https://archiv.ub.uni-heidelberg.de/voll   |
| << Previous Day |
2024/10/09 [Calendar] |
Next Day >> |