A new elasmosaurid from the early Maastrichtian of Angola and the implications of girdle morphology on swimming style in plesiosaurs

2015 ◽  
Vol 94 (1) ◽  
pp. 109-120 ◽  
Author(s):  
R. Araújo ◽  
M.J. Polcyn ◽  
A.S. Schulp ◽  
O. Mateus ◽  
L.L. Jacobs ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Sister Taxon ◽  
New Taxon ◽  
Swimming Style

AbstractWe report here a new elasmosaurid from the early Maastrichtian at Bentiaba, southern Angola. Phylogenetic analysis places the new taxon as the sister taxon to Styxosaurus snowii, and that clade as the sister of a clade composed of (Hydrotherosaurus alexandrae (Libonectes morgani + Elasmosaurus platyurus)). The new taxon has a reduced dorsal blade of the scapula, a feature unique amongst elasmosaurids, but convergent with cryptoclidid plesiosaurs, and indicates a longitudinal protraction-retraction limb cycle rowing style with simple pitch rotation at the glenohumeral articulation. Morphometric phylogenetic analysis of the coracoids of 40 eosauropterygian taxa suggests that there was a broad range of swimming styles within the clade.

scholarly journals A new iguanodontian (Dinosauria: Ornithopoda) from the Early Cretaceous of Mongolia

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5300
Author(s):  
Terry A. Gates ◽  
Khishigjav Tsogtbaatar ◽  
Lindsay E. Zanno ◽  
Tsogtbaatar Chinzorig ◽  
Mahito Watabe
Keyword(s):  
Phylogenetic Analysis ◽  
Growth Stage ◽  
Phylogenetic Analyses ◽  
Type Specimen ◽  
Sister Taxon ◽  
New Taxon ◽  
Time Of Death ◽  
The North ◽  
Unusual Combination ◽  
Relationship Of

We describe a new iguanodontian ornithopod,Choyrodon barsboldigen. et sp. nov. from the Albian-aged Khuren Dukh Formation of Mongolia based on several partial skeletons interpreted to represent a subadult growth stage based on osteohistological features. This new taxon is diagnosed by many autapomorphies of the maxilla, nasal, lacrimal, opisthotic, predentary, and surangular.Choyrodondisplays an unusual combination of traits, possessing an open antorbital fenestra (a primitive ornithopod trait) together with derived features such as a downturned dentary and enlarged narial fenestra. Histological imaging suggests that the type specimen ofChoyrodonwould have been a subadult at the time of death. Phylogenetic analysis of two different character matrices do not positChoyrodonto be the sister taxon or to be more primitive than the iguanodontianAltirhinus kurzanovi, which is found in the same formation. The only resolved relationship of this new taxon is that it was hypothesized to be a sister-taxon with the North American speciesEolambia caroljonesa. Though discovered in the same formation andChoyrodonbeing smaller-bodied thanAltirhinus, it does not appear that the former species is an ontogimorph of the latter. Differences in morphology and results of the phylogenetic analyses support their distinction although more specimens of both species will allow better refinement of their uniqueness.

scholarly journals Osteology of the Permian temnospondyl amphibian <i>Glanochthon lellbachae</i> and its relationships

Fossil Record ◽  
2021 ◽  
Vol 24 (1) ◽  
pp. 49-64
Author(s):  
Rainer R. Schoch
Keyword(s):  
Phylogenetic Analysis ◽  
Lateral Margin ◽  
Sister Taxon ◽  
Time Interval ◽  
New Taxon ◽  
Early Permian ◽  
Apex Predators ◽  
Trophic Guild ◽  
Long Time ◽  
Registration Date

Abstract. The early Permian Meisenheim Formation of the Saar–Nahe Basin (Germany) is famous for its richness in vertebrate fossils, among which the temnospondyls were present with microvores and fish-eating apex predators. The latter trophic guild was occupied exclusively by the genus Sclerocephalus in that basin within a long time interval up to M8, whereas in M9, a new taxon, Glanochthon lellbachae, appeared. This taxon is defined by (1) a preorbital region 1.8–2.0 times as long as the postorbital skull table, (2) dermal ornament with tall radial ridges, (3) a prefrontal anteriorly wider with straight lateral margin, (4) a squamosal posteriorly only half as wide as the quadratojugal, (5) phalanges of manus and pes long and gracile, (6) carpals unossified in adults, and (7) tail substantially longer than skull and trunk combined. Phylogenetic analysis finds that G. lellbachae forms the basal sister taxon of the stratigraphically younger G. angusta and G. latirostre and that this clade nests within the paraphyletic taxon Sclerocephalus, with S. nobilis forming the sister taxon of the genus Glanochthon (urn:lsid:zoobank.org:act:3038F794-17B9-4FCA-B241-CCC3F4423651; registration date: 15 March 2021).

A new ceratopsid from the Foremost Formation (middle Campanian) of Alberta

2012 ◽  
Vol 49 (10) ◽  
pp. 1251-1262 ◽  
Author(s):  
Michael J. Ryan ◽  
David C. Evans ◽  
Kieran M. Shepherd
Keyword(s):  
Phylogenetic Analysis ◽  
Type Species ◽  
New Genus ◽  
Sister Taxon ◽  
Low Density ◽  
New Taxon

Xenoceratops foremostensis gen. et. sp. nov., a new centrosaurine ceratopsid from the Foremost Formation (Campanian) of Alberta, is described based on frill material from at least three adult-sized individuals collected from a low-density bone bed. The material can be assigned to Centrosaurinae based on features of the preserved squamosal. Although the parietals are incomplete, the shape of the diagnostic parietal can be inferred from several overlapping serial elements. The parietal of the new taxon shares with all other centrosaurines, except Centrosaurus apertus , spike-like ornamentation at the posterolateral (P3) locus under traditional coding methods. At approximately 78 Ma, it is the oldest known Canadian ceratopsid, approximately 0.5 Ma older than Albertaceratops from the lower Oldman Formation of Canada and approximately 1.0 Ma younger than Diabloceratops from the Wahweap Formation of Utah. A phylogenetic analysis resolves the new taxon as the basalmost centrosaurine and places Centrosaurus brinkmani as the sister taxon to Styracosaurus albertensis . The type species of Centrosaurus brinkmani is moved to a new genus.

scholarly journals A new Barremian (Early Cretaceous) ichthyosaur from western Russia

2018 ◽  
Author(s):  
Valentin Fischer ◽  
Edwige Masure ◽  
Maxim S. Arkhangelsky ◽  
Pascal Godefroit
Keyword(s):  
Phylogenetic Analysis ◽  
Early Cretaceous ◽  
Sister Taxon ◽  
New Taxon ◽  
Skull Roof

A new ophthalmosaurid ichthyosaur, Sveltonectes insolitus, gen. et sp. nov., is described from a sub-complete and three-dimensionally preserved specimen from the late Barremian of western Russia. This new taxon is supported by 11 cranial, dental, and postcranial autapomorphies, and is also characterized by features previously considered as autapomorphic for some other Ophthalmosauridae, such as a processus narialis on the prefrontal and relatively long hind fins with pre- and postaxial accessory digits. We conducted a new phylogenetic analysis of Thunnosauria, which supports a ‘Stenopterygius’ origin for Ophthalmosauridae. Sveltonectes is regarded as the sister taxon of Aegirosaurus, which shares a similar skull roof construction. Contrary to most other Cretaceous ichthyosaurs, Sveltonectes is characterized by delicate and sharply pointed teeth, confirming that the ophthalmosaurids were ecologically highly diversified during the Early Cretaceous.

scholarly journals Evolutionary significance of the blastozoan Eumorphocystis and its pseudo-arms

2020 ◽  
pp. 1-17
Author(s):  
Thomas E. Guensburg ◽  
James Sprinkle ◽  
Rich Mooi ◽  
Bertrand Lefebvre
Keyword(s):  
Phylogenetic Analysis ◽  
Sister Taxon ◽  
Evolutionary Significance ◽  
Coelomic Cavity ◽  
Anatomical Features ◽  
New Findings ◽  
Solid Block ◽  
Cover Plates

Abstract Twelve specimens of Eumorphocystis Branson and Peck, 1940 provide the basis for new findings and a more informed assessment of whether this blastozoan (a group including eocrinoids, blastoids, diploporites, rhombiferans) constitutes the sister taxon to crinoids, as has been recently proposed. Both Eumorphocystis and earliest-known crinoid feeding appendages express longitudinal canals, a demonstrable trait exclusive to these taxa. However, the specimen series studied here shows that Eumorphocystis canals constrict proximally and travel within ambulacrals above the thecal cavity. This relationship is congruent with a documented blastozoan pattern but very unlike earliest crinoid topology. Earliest crinoid arm cavities lie fully beneath floor plates; these expand and merge directly with the main thecal coelomic cavity at thecal shoulders. Other associated anatomical features echo this contrasting comparison. Feeding appendages of Eumorphocystis lack two-tiered cover plates, podial basins/pores, and lateral arm plating, all features of earliest crinoid ‘true arms.’ Eumorphocystis feeding appendages are buttressed by solid block-like plates added during ontogeny at a generative zone below floor plates, a pattern with no known parallel among crinoids. Eumorphocystis feeding appendages express brachioles, erect extensions of floor plates, also unknown among crinoids. These several distinctions point to nonhomology of most feeding appendage anatomy, including longitudinal canals, removing Eumorphocystis and other blastozoans from exclusive relationship with crinoids. Eumorphocystis further differs from crinoids in that thecal plates express diplopores, respiratory structures not present among crinoids, but ubiquitous among certain groups of blastozoans. Phylogenetic analysis places Eumorphocystis as a crownward blastozoan, far removed from crinoids.

scholarly journals The putative lissamphibian stem-group: phylogeny and evolution of the dissorophoid temnospondyls

2018 ◽  
Vol 93 (1) ◽  
pp. 137-156 ◽  
Author(s):  
Rainer R. Schoch
Keyword(s):  
Phylogenetic Analysis ◽  
Large Scale ◽  
Sensu Stricto ◽  
New Taxon ◽  
Stem Group ◽  
Phylogeny And Evolution

AbstractDissorophoid temnospondyls are widely considered to have given rise to some or all modern amphibians (Lissamphibia), but their ingroup relationships still bear major unresolved questions. An inclusive phylogenetic analysis of dissorophoids gives new insights into the large-scale topology of relationships. Based on a TNT 1.5 analysis (33 taxa, 108 characters), the enigmatic taxonPerryellais found to nest just outside Dissorophoidea (phylogenetic defintion), but shares a range of synapomorphies with this clade. The dissorophoids proper are found to encompass a first dichotomy between the largely paedomorphic Micromelerpetidae and all other taxa (Xerodromes). Within the latter, there is a basal dichotomy between the large, heavily ossified Olsoniformes (Dissorophidae + Trematopidae) and the small salamander-like Amphibamiformes (new taxon), which include four clades: (1) Micropholidae (Tersomius,Pasawioops,Micropholis); (2) Amphibamidae sensu stricto (Doleserpeton,Amphibamus); (3) Branchiosauridae (Branchiosaurus,Apateon,Leptorophus,Schoenfelderpeton); and (4) Lissamphibia. The generaPlatyrhinopsandEoscopusare here found to nest at the base of Amphibamiformes. Represented by their basal-most stem-taxa (Triadobatrachus,Karaurus,Eocaecilia), lissamphibians nest withGerobatrachusrather than Amphibamidae, as repeatedly found by former analyses.UUID:http://zoobank.org/dadf36db-e003-4af7-bfa7-44d79bc04450

scholarly journals First rebbachisaurid sauropod dinosaur from Asia

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246620
Author(s):  
Alexander Averianov ◽  
Hans-Dieter Sues
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Upper Cretaceous ◽  
Neural Spine ◽  
Lateral Side ◽  
New Taxon ◽  
Caudal Vertebra

Dzharatitanis kingi gen. et sp. nov. is based on an isolated anterior caudal vertebra (USNM 538127) from the Upper Cretaceous (Turonian) Bissekty Formation at Dzharakuduk, Uzbekistan. Phylogenetic analysis places the new taxon within the diplodocoid clade Rebbachisauridae. This is the first rebbachisaurid reported from Asia and one of the youngest rebbachisaurids in the known fossil record. The caudal is characterized by a slightly opisthocoelous centrum, ‘wing-like’ transverse processes with large but shallow PRCDF and POCDF, and the absence of a hyposphenal ridge and of TPRL and TPOL. The neural spine has high SPRL, SPDL, SPOL, and POSL and is pneumatized. The apex of neural spine is transversely expanded and bears triangular lateral processes. The new taxon shares with Demandasaurus and the Wessex rebbachisaurid a high SPDL on the lateral side of the neural spine, separated from SPRL and SPOL. This possibly suggests derivation of Dzharatitanis from European rebbachisaurids. This is the second sauropod group identified in the assemblage of non-avian dinosaurs from the Bissekty Formation, in addition to a previously identified indeterminate titanosaurian.

scholarly journals An early bothremydid (Testudines, Pleurodira) from the Late Cretaceous (Cenomanian) of Utah, North America

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2502 ◽  
Author(s):  
Walter G. Joyce ◽  
Tyler R. Lyson ◽  
James I. Kirkland
Keyword(s):  
Phylogenetic Analysis ◽  
Late Cretaceous ◽  
New Taxon ◽  
The Novel ◽  
Depositional Settings ◽  
Near Shore ◽  
Phylogenetic Hypotheses ◽  
North And South America ◽  
North And South ◽  
Early Late

BackgroundBothremydidae is a clade of extinct pleurodiran turtles known from the Cretaceous to Paleogene of Africa, Europe, India, Madagascar, and North and South America. The group is most diverse during the Late Cretaceous to Paleogene of Africa. Little is known, however, about the early evolution of the group.MethodsWe here figure and describe a fossil turtle from early Late Cretaceous deposits exposed at MacFarlane Mine in Cedar Canyon, southwestern Utah, USA. The sediments associated with the new turtle are utilized to infer its stratigraphic provenience and the depositional settings in which it was deposited. The fossil is compared to previously described fossil pleurodires, integrated into a modified phylogenetic analysis of pelomedusoid turtles, and the biogeography of bothremydid turtles is reassessed. In light of the novel phylogenetic hypotheses, six previously established taxon names are converted to phylogenetically defined clade names to aid communication.ResultsThe new fossil turtle can be inferred with confidence to have originated from a brackish water facies within the late Cenomanian Culver Coal Zone of the Naturita Formation. The fossil can be distinguished from all other previously described pleurodires and is therefore designated as a new taxon,Paiutemys tibertgen. et. sp. nov. Phylogenetic analysis places the new taxon as sister to the EuropeanPolysternon provinciale,Foxemys trabantiandFoxemys mechinorumat the base of Bothremydinae. Biogeographic analysis suggests that bothremydids originated as continental turtles in Gondwana, but that bothremydines adapted to near-shore marine conditions and therefore should be seen as having a circum-Atlantic distribution.

A new species of Maytenus (Celastraceae) from the Brazilian Atlantic Forest, with evidence of molecular phylogeny, and two new synonyms for Maytenus floribunda

Phytotaxa ◽  
2015 ◽  
Vol 231 (1) ◽  
pp. 53
Author(s):  
Leonardo Biral ◽  
Eric De Camargo Smidt ◽  
Mônica Bolson ◽  
Julio Antônio Lombardi
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Molecular Phylogeny ◽  
Atlantic Forest ◽  
New Taxon ◽  
Brazilian Atlantic Forest ◽  
Rain Forests ◽  
New Synonyms ◽  
A New Species

A new species of Maytenus has been discovered in the Brazilian Atlantic Forest. The new taxon, Maytenus nemorosa, occurs mostly in ombrophilous rain forests at an elevation of 500 m to 1200 m. Maytenus nemorosa resembles M. gonoclada but differs from it by possessing oblong-elliptical leaves with entire margins and larger fruits with thicker pericarp walls. A phylogenetic analysis was conducted with nrITS and plastid matK regions, including the new species and additional taxa available from the NCBI-GenBank. The results from the phylogenetic analysis places Maytenus nemorosa nested within a clade of species that have fruits possessing a coriaceous pericarp and close to both Maytenus gonoclada and Maytenus salicifolia, as expected from morphological similarities. Additionally, M. cardenasii and M. erythrocarpa, from Bolivia, are both recognized as new synonyms for M. floribunda after an examination of their descriptions, types, and diverse collections.

A new Xenungulata (Mammalia) from the Paleocene of Patagonia, Argentina

2008 ◽  
Vol 82 (2) ◽  
pp. 329-335 ◽  
Author(s):  
Javier N. Gelfo ◽  
Guillermo M. López ◽  
Mariano Bond
Keyword(s):  
Phylogenetic Analysis ◽  
South America ◽  
Phylogenetic Relationship ◽  
New Taxon ◽  
Parsimonious Tree ◽  
Late Paleocene ◽  
Direct Association ◽  
Mammalian Faunas ◽  
New Form ◽  
Preliminary Phylogenetic Analysis

A new form of Xenungulata Paula Couto, 1952 from red levels of the Peñas Coloradas Formation in a locality near Puerto Visser (45°17'S, 67°01'W), Chubut province, Argentina, is represented by a fragmentary left jaw with the m3 (MPEF-PV 1871). Notoetayoa gargantuai n. gen. and n. sp. is the first ever found in direct association with Carodnia feruglioi Simpson, 1935a which characterizes the incompletely known homonymous zone of the late Paleocene of Patagonia. A preliminary phylogenetic analysis, including representatives of “Condylarthra,” Litopterna, Notoungulata, Pyrotheria, Xenungulata and Astrapotheria, plus the characters that could be scored in the new taxon, was performed using TNT software. A single most parsimonious tree was obtained. Notoetayoa gargantuai has a closer phylogenetic relationship with the Xenungulate Etayoa bacatensis Villarroel, 1987 from the ?middle Paleocene of Colombia than with any other Tertiary ungulate group of South America. Notoetayoa gargantuai fills an important gap in the knowledge of the mammalian faunas from the Paleocene of Patagonia, particularly of the poorly known pre-Itaborian times.

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