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Tytuł:
New molluscs associated with biogenic substrates in Cenozoic deep-water sediments of Washington State
Autorzy:
Kiel, S
Goedert, J.L.
Powiązania:
https://bibliotekanauki.pl/articles/21866.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
deep sea
Eocene
deep water sediment
sediment
Cenozoic
new bivalve species
Gastropoda
Bivalvia
mollusc
Washington State
biogenic substrate
Oligocene
paleontology
Opis:
Cenozoic deep−water sediments of the Lincoln Creek, Makah, and Pysht formations in western Washington State, USA, contain sunken driftwood and whale bones that were colonized by invertebrates which largely depend on this type of transient habitat. These fossil woodand whale−fall faunules yielded six new mollusk species that appear to have been endemic to these biogenic microhabitats, except for one species which also occurs in cold−seep limestones. The new gastropod species are the neomphalid Leptogyra squiresi, the buccinid Colus sekiuensis, the allogastropod Xylodiscula okutanii, and the new bivalve species are the protobranch “Nuculana” posterolaevia, the mytilid Idas? olympicus, and the heterodont Thyasira xylodia.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Osteology and phylogeny of Late Jurassic ichthyosaurs from the Slottsmoya Member Lagerstätte (Spitsbergen, Svalbard)
Autorzy:
Delsett, L.L.
Robert, A.J.
Druckenmiller, P.S.
Hurum, J.H.
Powiązania:
https://bibliotekanauki.pl/articles/22418.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Phylogenetic relationships within the important ichthyosaur family Ophthalmosauridae are not well established, and more specimens and characters, especially from the postcranial skeleton, are needed. Three ophthalmosaurid specimens from the Tithonian (Late Jurassic) of the Slottsmøya Member Lagerstätte on Spitsbergen, Svalbard, are described. Two of the specimens are new and are referred to Keilhauia sp. and Ophthalmosauridae indet. respectively, whereas the third specimen consists of previously undescribed basicranial elements from the holotype of Cryopterygius kristiansenae. The species was recently synonymized with the Russian Undorosaurus gorodischensis, but despite many similarities, we conclude that there are too many differences, for example in the shape of the stapedial head and the proximal head of the humerus; and too little overlap between specimens, to warrant synonymy on species level. A phylogenetic analysis of Ophthalmosauridae is conducted, including all Slottsmøya Member specimens and new characters. The two proposed ophthalmosaurid clades, Ophthalmosaurinae and Platypterygiinae, are retrieved under some circumstances, but with little support. The synonymy of three taxa from the Slottsmøya Member Lagerstätte with Arthropterygius is not supported by the present evidence.
Źródło:
Acta Palaeontologica Polonica; 2019, 64, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new genus of chemosymbiotic vesicomyid bivalves from the Oligocene of western North America
Autorzy:
Hybertsen, F.
Goedert, J.L.
Kiel, S.
Powiązania:
https://bibliotekanauki.pl/articles/31341392.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
new genus
bivalve
Bivalvia
Vesicomyidae
Oligocene
North America
cold-seep deposit
deep-water formation
Źródło:
Acta Palaeontologica Polonica; 2022, 67, 3; 703-709
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The systematics of Late Jurassic tyrannosauroid theropods from Europe and North America
Autorzy:
Brusatte, S.L.
Benson, R.B.J.
Powiązania:
https://bibliotekanauki.pl/articles/22629.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
systematics
Late Jurassic
tyrannosauroid theropod
theropod
Europe
North America
Dinosauria
Theropoda
Tyrannosauridae
Tyrannosaurus
anatomy
Jurassic
paleontology
Opis:
Recent discoveries of more than ten new species of tyrannosauroid theropods are helping to understand the origin and evolu− tion of colossal body size and other characteristic features of Tyrannosaurus rex and its terminal Cretaceous relatives. Partic− ularly important has been the discovery and reinterpretation of Late Jurassic tyrannosauroids from Europe and North Amer− ica, which are intermediate in size and phylogenetic position between small basal tyrannosauroids and the largest Late Cre− taceous species. The fragmentary nature of these Jurassic specimens, however, has frustrated attempts to understand their systematics and phylogeny. A new specimen from the Late Jurassic of England was recently named as a new species (Stokesosaurus langhami) of the genus Stokesosaurus, which is known from several fragmentary fossils from North Amer− ica. We review the systematics and phylogeny of these European and North American specimens and show that there are no unequivocal synapomorphies uniting them. Furthermore, a revised phylogenetic analysis does not recover them as sister taxa. This necessitates a taxonomic revision of this material, and we name a new genus (Juratyrant) for theBritish specimen.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Helodermatid lizard from the Mio-Pliocene oak-hickory forest of Tennessee, eastern USA, and a review of monstersaurian osteoderms
Autorzy:
Mead, J.I.
Schubert, B.W.
Wallace, S.C.
Swift, S.L.
Powiązania:
https://bibliotekanauki.pl/articles/20494.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
helodermatid lizard
lizard
Miocene
oak-hickory forest
Tennessee
USA
monstersaurian osteoderm
osteoderm
Reptilia
Squamata
Helodermatidae
Heloderma
beaded lizard
Hemphillian
Pliocene
North America
paleontology
Opis:
The extant venomous Gila monster and beaded lizards, species of Heloderma, live today in southwestern USA and south along the Pacific coastal region into Central America, but their fossil history is poorly understood. Here we report helodermatid osteoderms (dermal ossicles) from the late Miocene–early Pliocene Gray Fossil Site, eastern Tennessee USA. Twenty−three species of mammals are known from the fauna including abundant Tapirus polkensis, as well as fishes, anurans, salamanders, turtles, Alligator, birds, and snakes. Beaded lizards belong to the Monstersauria, a clade that includes Primaderma + Paraderma + Gobiderma + Helodermatidae (Estesia, Eurheloderma, Lowesaurus, and Heloderma). Osteoderms of lizards in this clade are unique within Squamata; they typically are circular to polygonal in outline, domed to flat−domed in cross−section, have a vermiculate surface texture, are not compound structures, and do not have imbricate surfaces as on many scincomorph and anguid lizards. We review and characterize the osteoderms of all members of Monstersauria. Osteoderms from the cranium, body, and limbs of Heloderma characteristically have a ring−extension (bony flange) at least partly surrounding the dome. Its presence appears to be a key character distinct to all species of Heloderma, consequently, we propose the presence of a ring−extension to be an apomorphy. Three osteoderms from the Gray Fossil Site range from 1.5 to 3.0 mm in diameter, have the circular shape of helodermatid osteoderms with a domed apical surface, and have the ring−extensions, permiting generic identification. Macrobotanical remains from the Gray Fossil Site indicate an oak−hickory subtropical forest dominated by Quercus (oak) and Carya (hickory) with some conifer species, an understorey including the climbing vines Sinomenium, Sargentodoxa, and Vitis. Plant and mammal remains indicate a strong Asian influence.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new neolepadid cirripede from a Pleistocene cold seep, Krishna-Godavari Basin, offshore India
Autorzy:
Gale, A.S.
Little, C.T.S.
Johnson, J.E.
Giosan, L.
Powiązania:
https://bibliotekanauki.pl/articles/2082175.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Cirripedia
Thoracica
Neolepadidae
cold seep
Pleistocene
Indian Ocean
Opis:
Valves of a thoracican cirripede belonging to a new species of the Neolepadidae, Ashinkailepas indica Gale sp. nov. are described from a Late Pleistocene cold seep (52.6 ka), cored in the Krishna-Godavari Basin, offshore from the eastern coast of India. This constitutes the first fossil record of the genus, and its first occurrence in the Indian Ocean. Other fossil records of the Neolepadidae (here elevated to full family status) are discussed, and it is concluded that only Stipilepas molerensis from the Eocene of Denmark, is correctly referred to the family. Cladistic analysis of the Neolepadidae supports a basal position for Ashinkailepas, as deduced independently from molecular studies, and the Lower Cretaceous brachylepadid genus Pedupycnolepas is identified as sister taxon to Neolepadidae. Neolepadids are not Mesozoic relics as claimed, preserved in association with the highly specialised environments of cold seeps and hydrothermal vents, but are rather an early Cenozoic offshoot from the clade which also gave rise to the sessile cirripedes.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 2; 351-362
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new genus of eomyid rodent from the Miocene of Nevada
Autorzy:
Smith, K S
Cifelli, R.L.
Czaplewski, N.J.
Powiązania:
https://bibliotekanauki.pl/articles/21894.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Megapeomys
Miocene
eomyid rodent
Apeomys
Rodentia
Nevada
Eomyidae
new genus
rodent
paleontology
Apeomyoides
Opis:
The description of a new genus (Apeomyoides) of eomyid rodent from the Miocene of Nevada increases the diversity of known taxa, enhances the geographic range, and extends the biochronology for the Apeomyinae (Eomyidae). Three groups of Eomyidae are known from the fossil record of North America. Of the three groups, Neogene taxa include four genera representing the Eomyinae and two genera representing the Apeomyinae; no genera of the subfamily Yoderimyinae are known from the Neogene of the continent. This diversity represents a significant reduction of eomyid taxa compared to the Paleogene, from which 17 genera of eomyines and three genera of yoderimyines are known. In Eurasia, 11 genera of eomyids occurred during the Neogene, with a few taxa that persisted until about 2 million years before present. At present, there are no known eomyids from the last 4.5 million years of the Neogene in North America. Apeomyoides savagei is referable to the subfamily Apeomyinae based on several key structures of the teeth and mandible. This new eomyid is part of the Eastgate local fauna, collected from volcanic ash deposits of the Monarch Mill Formation, Churchill County, Nevada. Apeomyoides has an occlusal pattern that shares characteristics of apeomyines from both North America (Megapeomys and Arikareeomys) and Eurasia (Apeomys and Megapeomys). The unique occlusal pattern and large size of Apeomyoides demonstrates that not all eomyids from North America were small or that their lineages decreased in size through time. Apeomyoides also may provide evidence, which challenges the hypothesis that eomyids within a single lineage from North America became more lophodont in geologically younger genera.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New artiodactyl ruminant mammal from the Late Oligocene of Pakistan
Autorzy:
Metais, G
Antoine, P.O.
Marivaux, L.
Welcomme, J.L.
Ducrocq, S.
Powiązania:
https://bibliotekanauki.pl/articles/20876.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Ruminantia
ruminant
Palaeohypsodontus zinensis
mammal
Bovidae
Mammalia
artiodactyl ruminant
Oligocene
Pakistan
Late Oligocene
paleontology
Opis:
Dental and postcranial material of the bovid−like ruminant Palaeohypsodontus zinensis sp. nov. is reported from the Oligocene of the Bugti Hills (Balochistan, Pakistan). This finding extends the geographic distribution of this dentally highly derived ruminant, which was previously restricted to the early Oligocene of Mongolia and China. The inclusion of Palaeohypsodontus within the Bovidae is disputed on the basis of astragalus characters, and the taxonomic status of the Oligo−Miocene Eurasian bovid−like ruminants is briefly discussed. It is concluded that the assignment of Palaeohypsodontus to the Bovidae would be premature. More dental and postcranial material of this genus as well as additional fossils of early bovids are necessary to shed new light on the phylogenetic relationships within the first representatives of that family in Eurasia.
Źródło:
Acta Palaeontologica Polonica; 2003, 48, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Jiyuan tetrapod fauna of the Upper Permian of China: new pareiasaur material and the reestablishment of Honania complicidentata
Autorzy:
Xu, L.
Li, X.-W.
Jia, S.-H.
Liu, J.
Powiązania:
https://bibliotekanauki.pl/articles/22012.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Honania complicidentata and Tsiyuania simplicidentata are pareiasaur taxa based on material from the Shangshihezi Formation of Jiyuan, Henan Province, China that were earlier designated as nomina vana. Based on the study of new material, and the reexamination of old specimens, we determine that the pareiasaur material from Jiyuan represents a single species that differs from all known species from other localities. Thus, we resurrect the name H. complicidentata for the material from Jiyuan. H. complicidentata is characterized by maxillary teeth with high crowns, dentary teeth slightly posteriorly inclined compared to the dentary dorsal margin, nearly all preserved marginal teeth have a cusped cingulum on the lingual surface, and humerus without an ectepicondylar foramen. Phylogenetic analysis shows Honania is more basal than Shansisaurus and Shihtienfenia from the Sunjiagou Formation of China.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cyanobacterial key to the genesis of micritic and peloidal limestones in ancient seas
Cyjanobakteryjna geneza wapieni mikrytowych i peloidalnych w dawnych zbiornikach morskich
Autorzy:
Kazmierczak, J
Coleman, M L
Gruszczynski, M
Kempe, S
Powiązania:
https://bibliotekanauki.pl/articles/20317.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
osady wapniowe
Gory Swietokrzyskie
wapienie peloidalne
srodowisko morskie
aragonit
wapienie mikrytowe
jura
kalcyt
mikroorganizmy
paleontologia
sinice
zbiorniki morskie
Opis:
The origin of micritic and peloidal limestones comprising the bulk of many ancient marine carbonate deposits represents a major unsolved problem of carbonate sedimentology. Our studies of such limestones from a sequence of Late Jurassic open marine sediments exposed in central Poland revealed them as products of in situ calcified mats of benthic coccoid cyanobacteria. Remains of the cyanobacteria are visible in scanning electron microscope (SEM) images as characteristic patterns closely resembling the common mucilage sheaths of modern entophysalidacean and/or pleurocapsalean cyanobacteria comparable to those we found producing micritic and peloidal microbialites in Lake Van, Turkey. We suggest, by analogy, that many subtidal micritic and peloidal limestones common in the marine sedimentary record might be products of similar in situ calcified cyanobactend microbiota. Such an intensive calcification of marine cyanobacteria could have proceeded only in environments more than modern seawater supersaturated with respect to calcium carbonate minerals. Advection of excess alkalinity, originating from deeper, anaerobic or dysaerobic zones to shallow water areas is proposed as the main factor enhancing colonization of extensive sea bottom areas by the alkaliphilic cyanobacteria and promoting their in uiuo calcification.
Geneza wapieni mikrytowych i peloidalnych, głównych składników większości kopalnych morskich formacji wapiennych, nie została do tej pory rozwiązana i od ponad stu lat jest jednym z bardziej kontrowersyjnych problemów sedymentologii i petrologii skał węglanowych. Przedstawione w pracy wyniki badań nad takimi wapieniami z utworów późnej jury (kimerydu) Gór Świętokrzyskich wykazały, że osady te są wytworem in situ zwapniałych bentosowych mat kokkoidalnych cyjanobakterii (= sinic). Szczątki tych mikroorganizmów widoczne są w skaningowym mikroskopie elektronowyrn w postaci charakterystycznych struktur, przypominających wspólne osłony śluzowe (glycocalyx) otaczające komórki i grupy komórek w koloniach dzisiejszych bentosowych kokkoidalnych cyjanobakterii zaliczanych do grup Chroococcales (szczególnie Entophysalis) i Pleurocapsales (Pleurocapsa). Szczegółowe badania porównawcze przeprowadzone zostały na dzisiejszych, w różnym stopniu zwapniałych matach takich cyjanobakterii występujących w alkalicznym (sodowym) Jeziorze Wan (wschodnia Turcja). Wyniki tych badań pozwalają wnioskować, że zarówno mikrytowe i peloidalne wapienie jurajskie, jak i miąższe serie podobnych morskich wapieni pospolitych w zapisie litologicznym innych okresów geologicznych są produktem in situ zwapniałych mat kokkoidalnych cyjanobakterii. Istnieją podstawy aby przypuszczać, iż tak intensywna kalcyfikacja morskich cyjanobakterii mogła odbywać się jedynie w środowisku, które w porównaniu z dzisiejszą wodą morską było bardziej przesycone w stosunku do produktu rozpuszczalności takich pospolitych minerałów węglanowych jak kalcyt i aragonit. Głównym czynnikiem utrzymującym wyższy od obecnego poziom przesycenia węglanem wapnia w dawnych środowiskach morskich był najprawdopodobniej napływ do fotycznej strefy zasiedlonej przez cyjanobakterie ekscesywnie alkalicznych wód pochodzących z głębszych, anaerobowych (stratyfikowanych) lub dysaerobowych partii zbiorników, których podwyższona alkaliczność była wynikiem metabolicznej aktywności bakterii redukujących siarczany w procesie remineralizacji substancji organicznej w strefach deficytu tlenowego.
Źródło:
Acta Palaeontologica Polonica; 1996, 41, 4; 319-338
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A reassessment of Kelmayisaurus petrolicus, a large theropod dinosaur from the Early Cretaceous of China
Autorzy:
Brusatte, S.L.
Benson, R.B.J.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/21593.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Kelmayisaurus petrolicus
large theropod dinosaur
theropod dinosaur
Early Cretaceous
China
Dinosauria
Theropoda
Carcharodontosauridae
anatomy
Cretaceous
Opis:
The Early Cretaceous fossil record of large−bodied theropods from Asia is poor, hindering comparison of Asian predatory dinosaur faunas with those from other continents. One of the few large Asian theropod specimens from this interval is a partial skull (maxilla and dentary) from the Lianmugin Formation (?Valanginian–Albian), the holotype of Kelmayisaurus petrolicus. Most authors have either considered this specimen as an indeterminate basal tetanuran or a nomen dubium. We redescribe K. petrolicus and note that it possesses a single autapomorphy (a deep accessory groove on the lateral surface of the anterior dentary), as well as a unique combination of characters that differentiates it from other theropods, affirming its validity. A phylogenetic analysis recovers K. petrolicus as a basal carcharodontosaurid, which is supported by various features: very deep interdental plates (a carcharodontosaurid synapomorphy), fused interdental plates (present in carchardontosaurids and a limited number of other theropods), and the absence of diagnostic features of other clades of large−bodied theropods such as abelisaurids, megalosauroids, and coelurosaurs. As such,Kelmayisaurusis the second known carcharodontosaurid from Asia, and further evidence that this clade represented a global radiation of large−bodied predators during the Early–mid Cretaceous.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The taxonomy and anatomy of rauisuchian archosaur from the Late Triassic of Germany and Poland
Autorzy:
Brusatte, S L
Butler, R.J.
Sulej, T.
Niedzwiedzki, G.
Powiązania:
https://bibliotekanauki.pl/articles/21870.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
taxonomy
paleontology
rauisuchian archosaur
archosaur
Late Triassic
Germany
Polska
Teratosaurus suevicus
Teratosaurus silesiacus
Postosuchus kirkpatricki
Polonosuchus
Archosauria
Rauisuchia
Triassic
anatomy
Opis:
The German Late Triassic archosaur Teratosaurus suevicus is a historically important taxon, being the first described rauisuchian. Unfortunately the holotype is a single element, a maxilla, which is poorly preserved and incomplete. We redescribe this maxilla and identify a single potential autapomorphy. The fragmentary type specimen complicates attempts to refer additional material to this taxon, and other unassociated archosaur and rauisuchian specimens from the Mittlerer Stubensandstein of Germany cannot be referred to T. suevicus with any degree of confidence. The stratigraphically older T. silesiacus, from the upper Carnian of Poland, is represented by a much more complete and better preserved specimen. Comparison of the maxillae of T. suevicus and T. silesiacus reveals that the two are distinct taxa, contra recent suggestions, but also that they do not share any synapomorphies or a unique combination of characters relative to Postosuchus kirkpatricki and other rauisuchians. Thus, the Polish material must be transferred to a new genus, Polonosuchus gen. nov. Both Polonosuchus and Teratosaurus are very similar to Postosuchus kirkpatricki, and the three taxa are likely closely related.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 2; 221-230
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A partial skeleton of an enantiornithine bird from the Early Cretaceous of Northwestern China
Autorzy:
Lamanna, M.C.
You, H.-L.
Harris, J.D.
Chiappe, L.M.
Ji, S.-A.
Lu, J.-C.
Ji, Q.
Powiązania:
https://bibliotekanauki.pl/articles/20670.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
China
Cretaceous
Early Cretaceous
paleontology
skeleton
partial skeleton
bird
Aves
enantiornithine bird
Enantiornithes
Xiagou Formation
remains
Opis:
Although recent discoveries from Lower Cretaceous sediments in northeastern China have greatly improved our understanding of the initial stages of avian diversification in eastern Asia, the early evolution of Aves elsewhere on the continent remains poorly understood. In 2004, a collaborative field effort directed by personnel from the Chinese Academy of Geological Sciences and Carnegie Museum of Natural History recovered multiple partial to nearly complete avian skeletons from outcrops of the Lower Cretaceous Xiagou Formation exposed in the Changma Basin of northwestern Gansu Province, China. Here we describe a thrush−sized partial skeleton comprised of a fragmentary pelvic girdle and largely complete hind limbs. A phylogenetic analysis of 20 avian ingroup taxa and 169 anatomical characters places the specimen in Enantiornithes, and within that clade, in Euenantiornithes. When coupled with additional recent discoveries from the Changma Basin, the new skeleton improves our understanding of early avian evolution and diversification in central Asia.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new troodontid theropod from the Late Cretaceous of central China, and the radiation of Asian troodontids
Autorzy:
Lu, J
Xu, L.
Liu, Y.
Zhang, X.
Jia, S.
Ji, Q.
Powiązania:
https://bibliotekanauki.pl/articles/20912.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
new theropod
Late Cretaceous
Central China
Asian troodontid
troodontid
Theropoda
Troodontidae
Xixiasaurus
Cretaceous
Henan province
China
paleontology
Opis:
A new troodontid dinosaur, Xixiasaurus henanensis gen. et sp. nov., from the Upper Cretaceous Majiacun Formation of the Xixia Basin, Henan Province, is erected, based on a partial skull. It is characterized by bearing 22 maxillary teeth, a distinct opening on the lateral surface of the base of nasal process of the premaxilla, the rostral end of the upper jaw forming a tapered U−shape, and the mandibular symphyseal region slightly inflected medially. Xixiasaurus is most closely related to the Mongolian Byronosaurus among troodontids. Byronosaurus, Urbacodon, and Xixiasaurus may form a new clade, suggesting an endemic radiation of troodontids across Asia, including multiple taxa without dental serrations. The discovery of Xixiasaurus in the Xixia Basin may imply that the Xixiasaurus−bearing Majiacun Formation is Campanian in age.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 3; 381-388
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Postcranial remains of basal typotherian notoungulates from the Eocene of northwestern Argentina
Autorzy:
Armella, M.A.
Garcia-Lopez, D.A.
Babot, M.J.
Deraco, V.
Herrera, C.M.
Saade, L.
Bertelli, S.
Powiązania:
https://bibliotekanauki.pl/articles/2082173.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Mammalia
Notoungulata
calcaneum
astragalus
plantigrade
foot stances
Paleogene
South America
Opis:
Notoungulates represent the most taxonomically diverse and temporally and geographically widespread group among South American native ungulates. Here, we analyze anatomical and systematic aspects of proximal tarsal bones recovered from the Lower and Upper Lumbrera formations (middle and late middle Eocene) in northwestern Argentina. We provide detailed descriptions, comparisons, and infer foot stances and range of movements for the taxa implicated. Material studied includes astragali belonging to the oldfieldthomasiid Colbertia lumbrerense (Lower Lumbrera Formation), a set of proximal tarsals referred as Typotheria indet. (Lower Lumbrera Formation), and tarsals (also including navicular and cuboid) of the informal taxon “Campanorco inauguralis” (Upper Lumbrera Formation). The comparison of the tarsals of Colbertia lumbrerense (middle Eocene of Argentina) with Colbertia magellanica (early Eocene of Brazil) reveals several differences including variations on the development and arrangement of articular facets, and the size of the dorsal astragalar foramen in the Argentinean species. The specimen of Typotheria indet. shows morphological affinities with basal interatheriid taxa. However, its larger size contrasting with the overall small body sizes of Eocene interatheriids precludes an indisputable taxonomic assignment. Concerning “Campanorco inauguralis”, our observations indicate that there is no morphological evidence for a close phylogenetic relationship with Mesotheriidae. It presents a “reversed alternating tarsus” condition, which is also observed in Leontiniidae, “Notohippidae”, Toxodontidae, and some typotherians. However, the spectrum of singularities exhibited by this form precludes the assessment of its relationships in the context of the Paleogene radiation of Typotheria and it is necessary to extend the comparison to Eocene notoungulates. Finally, in a morphofunctional context a plantigrade foot posture is inferred for the specimens here reported. These observations have the potential to provide functional proxies for paleoecological reconstructions to be applied to the study of the early radiation of these notoungulate faunas.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 2; 1-17
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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