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Tytuł:
Fish remains, mostly otoliths, from the non-marine early Miocene of Otago, New Zealand
Autorzy:
Schwarzhans, W.
Scofield, R.P.
tennyson, A.J.D.
Worthy, J.P.
Worthy, T.H.
Powiązania:
https://bibliotekanauki.pl/articles/23337.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fish remains
remains
otolith
Early Miocene
Miocene
Otago
New Zealand
Pisces
Eleotridae
Galaxiidae
Retropinnidae
Mataichthys
freshwater fish
Bannockburn Formation
Mataichthys bictenatus
Galaxias angustiventris
Galaxias bobmcdowalli
Galaxias brevicauda
Galaxias papilionis
Galaxias parvirostris
Galaxias tabidus
Prototroctes modestus
Prototroctes vertex
Mataichthys procerus
Mataichthys rhinoceros
Mataichthys taurinus
Opis:
Fish remains described from the early Miocene lacustrine Bannockburn Formation of Central Otago, New Zealand, consist of several thousand otoliths and one skeleton plus another disintegrated skull. One species, Mataichthys bictenatus Schwarzhans, Scofield, Tennyson, and T. Worthy gen. et sp. nov., an eleotrid, is established on a skeleton with otoliths in situ. The soft embedding rock and delicate, three−dimensionally preserved fish bones were studied by CT−scanning technology rather than physical preparation, except where needed to extract the otolith. Fourteen species of fishes are described, 12 new to science and two in open nomenclature, representing the families Galaxiidae (Galaxias angustiventris, G. bobmcdowalli, G. brevicauda, G. papilionis, G. parvirostris, G. tabidus), Retropinnidae (Prototroctes modestus, P. vertex), and Eleotridae (Mataichthys bictenatus, M. procerus, M. rhinoceros, M. taurinus). These findings prove that most of the current endemic New Zealand/southern Australia freshwater fish fauna was firmly established in New Zealand as early as 19–16 Ma ago. Most fish species indicate the presence of large fishes, in some cases larger than Recent species of related taxa, for instance in the eleotrid genus Mataichthys when compared to the extant Gobiomorphus. The finding of a few otoliths from marine fishes corroborates the age determination of the Bannockburn Formation as the Altonian stage of the New Zealand marine Tertiary stratigraphy.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cranial osteology and ontogeny of Saurolophus angustirostris from the Late Cretaceous of Mongolia with comments on Saurolophus osborni from Canada
Autorzy:
Bell, P.R.
Powiązania:
https://bibliotekanauki.pl/articles/21134.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Reanalysis of the skull of the crested Asian hadrosaurine Saurolophus angustirostris confirms its status as a distinct species from its North American relative, Saurolophus osborni. In addition to its greater absolute size, S. angustirostrisis differentiated from Saurolophus osborni by an upturned premaxillary body, a more strongly reflected oral margin of the premaxilla, the absence of an anterior notch in the prenarial fossa, a sigmoidal contour of the ventral half of the anterior process of the jugal, a shallow quadratojugal notch on the quadrate, and by a strongly bowed quadrate in lateral view. Phylogenetic analysis corroborates a sister taxon relationship between S. angustirostris and S. osborni. Saurolophusitself is characterised by a solid, rod−like crest composed of the nasals, frontals, and prefrontals; secondary elongation of the frontal and prefrontal resulting in the backwards extension of the frontal platform; a frontal platform that extends dorsal to the anterior portion of the supratemporal fenestra; a parietal that is excluded by the squamosals from the posterodorsal margin of the occiput; and the presence of two supraorbital elements. Although the palaeobiogeographic history of Saurolophus remains unresolved, at least two possible dispersal events took place across Beringia during the late Campanian leading to the evolution of the clade composed of Kerberosaurus, Prosaurolophus, and Saurolophus.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discovery of Ordovician land plants
Odkrycie ordowickich roślin lądowych
Nakhodka ordovikskikh nazemnykh rastenijj
Autorzy:
Kozlowski, R.
Greguss, P.
Powiązania:
https://bibliotekanauki.pl/articles/21458.pdf
Data publikacji:
1959
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
In Ordovician erratic boulders land plants remains were found. They could be considered as more primitive than Psilophytales , and probably as the most primitive land plants. Two new genera : Musciphyton gen. nov. and Hepaticaephyton gen. nov. are distinguished.
W notatce tej autorzy informują o znalezieniu przez pierwszego z nich szczątków roślinnych wieku ordowickiego o charakterze roślin lądowych. Autor wypreparował te materiały z wapiennych narzutniaków ordowickich, zebranych w dolinie Wisły koło Zakroczymia, rozpuszczając je w kwasie solnym. Wapienie te, przywleczone ze Skandynawii przez lodowce czwartorzędowe, odpowiadają osadom morskim i zawierają szczątki zwierząt typowo morskich, jak graptolity, szkarłupnie, brachiopody, pierścienice (skolekodonty), hydroidy itp. Zawierają one tez grzyby niższe i algi ,zapewne również morskie. Wśród tych organizmów znalazły się jednak pewne rośliny o wyższej organizacji, które, według drugiego autora, są niewątpliwie lądowe. Rośliny te musiały być przyniesione do zbiornika morskiego z wybrzeży lądu. Odznaczają się one wyjątkowo doskonałym stanem zachowania. Szczegółowym ich badaniem zajął się drugi z autorów i wyniki je go pracy ogłoszone zastana w niedalekiej przyszłości. W niniejszej notatce wstępnej autor ten komunikuje, iż badane przez niego rośliny reprezentują dwa nowe rodzaje, którym nadaje nazwy Musciphyton i Hepaticaephyton, a grupę, do której będzie można je zaliczyć, nazywa prowizorycznie "Propsilophyta " . Są to rośliny pod wieloma względami prymitywniejsze, niż znane dotychczas z syluru i dewonu Psilophyta. Przypuszczalnie niewiele oddalają się one od teoretycznego prototypu roślin lądowych. Na razie autor ogranicza się do podania ogólnej tylko charakterystyki dwóch wyróżnionych przezeń rodzajów, ilustrując je zdjęciami fotograficznymi i rysunkami. Czyni równocześnie rozważania na temat znaczenia tego znaleziska dla zagadnienia pochodzenia i ewolucji roślin lądowych.
Źródło:
Acta Palaeontologica Polonica; 1959, 04, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A quasi-mammal from Lesotho
Autorzy:
Lees, P.M.
Mills, R.
Powiązania:
https://bibliotekanauki.pl/articles/23064.pdf
Data publikacji:
1983
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
The specimen described in this paper was discovered by the University College Expedition to Lesotho in 1968. It consists of most of the right maxilla. It contains the root of a large canine followed by an edentulous area which may contain the roots of one or more premolariform teeth. Posterior to this there is evidence of five molariform teeth. The most distal of these is probably the last molar. The molariform teeth are single rooted, while their crowns, although essentially single-cusped, have some resemblance to those of small contemporaneous true mammals of the family Morganucodontidae. The affinities of this animal are discussed in the paper, and it is suggested that there was an extensive fauna of small animals in the latest Triassic and earliest Jurassic, which although reptiles, had close affinities with the early mammals.
Źródło:
Acta Palaeontologica Polonica; 1983, 28, 1-2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Middle Miocene rodents from Pasalar, Anatolia, Turkey
Autorzy:
Pelaez-Campomanes, P
Daams, R.
Powiązania:
https://bibliotekanauki.pl/articles/20448.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Miocene
mammal
Turkey
Rodentia
Spermophilinus
Anatolia
rodent
Megacricetodon
Middle Miocene
biochronology
Democricetodon
Peridyromys
paleontology
Opis:
Despite the importance of the Paşalar fauna for the evolution and biogeography of Miocene mammals, few studies on its rodents have been published. In this paper a taxonomic analysis of the Paşalar rodents and the possible correlation that can be based on them are presented. Several rodent taxa, previously unknown from Paşalar are described. These include the cricetids Megacricetodon andrewsi sp. nov. and Democricetodon brevis (Schaub, 1925), the sciurids Spermophilinus bredai (Meyer, 1848) and Sciurinae indet., and the glirid Peridyromys lavocati sp. nov. The taxa previously described from Paşalar are: the ctenodactylid Sayimys cf. intermedius (Sen and Thomas, 1979), the cricetid Cricetodon pasalarensis (Tobien, 1978), the spalacid Pliospalax marmarensis Ünay, 1990 and the castorid cf. Chalicomys jaegeri Kaup, 1832. These determinations represent a reduction of the number of taxa recorded from the locality, as previous papers listed up to five sciurids. Only two sciurids and two glirids are recognized in this study. Mainly on the basis of the new cricetid records, it is possible to correlate the Paşalar fauna to late MN6.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chaetopterid tubes from vent and seep sites: Implications for fossil record and evolutionary history of vent and seep annelids
Autorzy:
Kiel, S
Dando, P.R.
Powiązania:
https://bibliotekanauki.pl/articles/23540.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
chaetopterid tube
vent
seep site
fossil record
evolution
history
annelid
fauna
paleontology
Vestimentifera
Pogonophora
Siboglinidae
Chaetopteridae
tubeworm
chemosynthetic ecosystem
hot vent
cold seep
Opis:
Vestimentiferan tube worms living at deep−sea hydrothermal vents and cold seeps have been considered as a clade with a long and continuing evolutionary history in these ecosystems. Whereas the fossil record appears to support this view, molecular age estimates do not. The two main features that are used to identify vestimentiferan tubes in the fossil record are longitudinal ridges on the tube’s surface and a tube wall constructed of multiple layers. It is shown here that chaetopterid tubes from modern vents and seeps—as well as a number of fossil tubes from shallow−water environments—also show these two features. This calls for a more cautious interpretation of tubular fossils from ancient vent and seep deposits. We suggest that: current estimates for a relatively young evolutionary age based on molecular clock methods may be more reliable than the inferences of ancient “vestimentiferans” based on putative fossils of these worms; not all of these putative fossils actually belong to this group; and that tubes from fossil seeps should be investigated for chitinous remains to substantiate claims of their potential siboglinid affinities.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 3; 443-448
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bone Microstructure and Relative Age of the Holotype Specimen of the Diplodocoid Sauropod Dinosaur Suuwassea emilieae
Autorzy:
Hedrick, B.P.
Tumarkin-Deratzian, A.R.
Dodson, P.
Powiązania:
https://bibliotekanauki.pl/articles/945796.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
dinosauria
sauropoda
suuwassea
histology
jurassic
morrison formation
montana
usa
Opis:
We present the first study of bone microstructure in Suuwassea emilieae, a diplodocoid sauropod from the Morrison Formation. Although the holotype of Suuwassea was recently identified as a subadult, bone histology demonstrates that this individual had reached sexual maturity at approximately 75–80% of maximum adult size. The smaller size of the holotype of Suuwassea relative to contemporary sauropods is due to ontogeny rather than a true reflection of adult size. A fully adult individual would have likely been similar in size to a fully adult specimen of Apatosaurus. Suuwassea has a number of plesiomorphic characters that might have been explained by its supposed early ontogenetic status, and would then have called the validity of the taxon into question. However, our demonstration that it was an adult confirms that these features represent retention of plesiomorphic character states or evolutionary reversals in a derived animal. Additionally, the specimen shows extensive cortical drift and secondary osteon formation related to skeletal loading, which is often obscured by complete remodeling of Haversian systems in sauropod taxa. There are substantial differences in the microstructure across the bone, which could make histologic samples not based upon complete cross sections problematic. Suuwassea is one of four currently recognized dicraeosaurid taxa, and this study contributes potential taxonomic characters in sauropod bone microstructure.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 2; 295-304
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unique bone histology in partial large bone shafts from Upper Triassic of Aust Cliff, England: An early independent experiment in gigantism
Autorzy:
Redelstorff, R.
Sander, P.M.
Galton, P.M.
Powiązania:
https://bibliotekanauki.pl/articles/945884.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Reptilia
Dinosauria
bone
histology
large bone shaft
primary osteon
secondary osteon
osteon
Upper Triassic
Triassic
Aust Cliff
England
gigantism
Opis:
Two giant partial bone shafts, possible femora, from the Rhaetian Bone Bed (Upper Triassic) of Aust Cliff in SW England continue to conceal their origin. The most striking characteristic of these bones is their size, showing that dinosaur-like gigantism had already evolved by the Late Triassic. Based on their characteristic, columnar shaft morphology, it was previously suggested they came from a prosauropod or stegosaur. The bone histology of both specimens is very similar: the cortex is always rather thin, not exceeding 10 mm, and is of fibrolamellar type with longitudinal primary osteons. The primary osteons show a rather unusual feature, the development of a secondary osteon inside the primary one. The bone surface in both specimens shows open vascular canals, suggesting that the animals were still growing at the time of death, but an external fundamental system (EFS) is visible in the outermost cortex of specimen BRSMG Cb3870. The external cortex shows dense growth marks, but their annual nature is difficult to ascertain. The bones are probably dinosaurian, as indicated by the fibrolamellar bone, and possibly belong to an unknown basal sauropodomorph lineage. Alternatively, some very large pseudosuchians may have evolved fibrolamellar bone independently as an adaptation for reaching giant size.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 3; 607-615
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new, morphologically diverse Permian trilobite fauna from Oman
Autorzy:
Fortey, R.A.
Heward, A.P.
Powiązania:
https://bibliotekanauki.pl/articles/945621.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Trilobita
morphology
fauna
new species
Simulopaladin tridentifer
Hentigia ornata
Iranaspidion elephas
Acanthophillipsia felicitae
Triproetus bonbon
paleogeography
Permian
Oman
Opis:
A newly discovered trilobite fauna from the early to middle Permian Qarari Unit of northeastern Sultanate of Oman is described. It comprises exceptionally complete and well-preserved examples of five proetoid species, belonging to genera typical of an eastern Tethyan region extending through southern Asia to Timor. The shallow shelf fauna compares closely with one of Artinskian age from Afghanistan. Permian species previously assigned to Paladin are here considered unrelated to this predominantly Carboniferous clade, and are placed in a new ditomopygine genus, Simulopaladin, type species Simulopaladin tridentifer sp. nov. Three other ditomopygine species are described: Hentigia ornata sp. nov., Iranaspidion elephas sp. nov., and Acanthophillipsia felicitae sp. nov. The proetid Triproetus bonbon sp. nov. is the most complete material known of a more widespread genus.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 1; 201-216
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bradoriid arthropods from the lower - middle Cambrian of Scania, Sweden
Autorzy:
Dies Alvarez, M.E.
Gozalo, R.
Cederstrom, P.
Ahlberg, P.
Powiązania:
https://bibliotekanauki.pl/articles/20703.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
bradoriid arthropod
arthropod
Cambrian
Scania
Sweden
paleontology
Arthropoda
Bradoriida
taxonomy
biostratigraphy
Opis:
Three species of bradoriid arthropods from the lower to middle Cambrian transitional interval of Scania, southern Sweden, are described and illustrated: Beyrichona tinea from the top of the traditional lower Cambrian (Gislöv Formation; Ornamentaspis? linnarssoni Zone), and Hipponicharion eos and Alutella sp. from the basal portion of the traditional middle Cambrian (lowermost part of the Alum Shale Formation). The bradoriid fauna compares most closely with others previously described from western and eastern Avalonia (New Brunswick and England). The record of B. tinea suggests a correlation between the “Protolenus Zone” (Hupeolenus Zone) of western Avalonia and the O.? linnarssoni Zone of Scandinavia. Hipponicharion eos appears to be a fairly long−ranging species as it has previously been recorded from upper lower Cambrian or lower middle Cambrian strata in New Brunswick, Poland, and probably Sardinia. The record of H. eos from the lowermost part of the Alum Shale Formation suggests that this largely unfossiliferous interval in the Scanian succession is not younger than the Acadoparadoxides oelandicus Superzone. The genus Alutella has not previously been recorded from the Acado−Baltic Province.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Late Cretaceous mammals from the Intertrappean beds of Rangapur, India and paleobiogeographic framework
Autorzy:
Rana, R S
Wilson, G.P.
Powiązania:
https://bibliotekanauki.pl/articles/21414.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Eutheria
mammal
Gondwana
Cretaceous
Late Cretaceous
tooth
Intertrappean bed
biogeography
India
Rangapur
paleobiogeography
paleontology
Opis:
A new mammal−bearing locality from the Intertrappean beds (Maastricthian) of Rangapur, Andhra Pradesh, India provides isolated teeth referable to Deccanolestes and a new eutherian, Sahnitherium rangapurensis. Dental comparisons with Cimolestes, Procerberus, and Aboletylestes do not support proposed “palaeoryctoid” affinities for Deccanolestes. Although similarities exist with Otlestes and Batodon, Deccanolestes is currently considered to be of uncertain familial affinities. Sahnitherium rangapurensis exhibits similarities to Procerberus, Paranyctoides, Alostera, Aboletylestes, and Avitotherium, but it is here placed within Eutheria incertae sedis. Despite family level taxonomic uncertainties, the new material confirms the presence of eutherians on the Indian subcontinent during the Late Cretaceous. A Eurasian connection via an early collision or some other dispersal route may explain these paleobiogeographic data, but other hypotheses are considered. In particular, paleogeographic, paleontological, and molecular systematic data hint that boreosphenidan mammals may have had wider distribution on Gondwana during the Cretaceous than previously supported.
Źródło:
Acta Palaeontologica Polonica; 2003, 48, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strophomenide and orthotetide Silurian brachiopods from the Baltic Region, with particular reference to Lithuanian boreholes
Autorzy:
Musteikis, P
Cocks, L.R.M.
Powiązania:
https://bibliotekanauki.pl/articles/22973.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Strophomenoidea
brachiopod
Plectambonitoidea
Silurian
Orthotetoidea
Lithuania
Baltic region
Brachiopoda
paleontology
borehole
Opis:
Epeiric seas covered the east and west parts of the old craton of Baltica in the Silurian and brachiopods formed a major part of the benthic macrofauna throughout Silurian times (Llandovery to Pridoli). The orders Strophomenida and Orthotetida are conspicuous components of the brachiopod fauna, and thus the genera and species of the superfamilies Plectambonitoidea, Strophomenoidea, and Chilidiopsoidea, which occur in the Silurian of Baltica are reviewed and reidentified in turn, and their individual distributions are assessed within the numerous boreholes of the East Baltic, particularly Lithuania, and attributed to benthic assemblages. The commonest plectambonitoids are Eoplectodonta (Eoplectodonta) (6 species), Leangella (2 species), and Jonesea (2 species); rarer forms include Aegiria and Eoplectodonta (Ygerodiscus), for which the new species E. (Y.) bella is erected from the Lithuanian Wenlock. Eight strophomenoid families occur; the rare Leptaenoideidae only in Gotland (Leptaenoidea, Liljevallia). Strophomenidae are represented by Katastrophomena (4 species), and Pentlandina (2 species); Bellimurina (Cyphomenoidea) is only from Oslo and Gotland. Rafinesquinidae include widespread Leptaena (at least 11 species) and Lepidoleptaena (2 species) with Scamnomena and Crassitestella known only from Gotland and Oslo. In the Amphistrophiidae Amphistrophia is widespread, and Eoamphistrophia, Eocymostrophia, and Mesodouvillina are rare. In the Leptostrophiidae Mesoleptostrophia, Brachyprion, and Protomegastrophia are common, but Eomegastrophia, Eostropheodonta, Erinostrophia, and Palaeoleptostrophia are only recorded from the west in the Baltica Silurian. In the Eopholidostrophidae, Mesopholidostrophia is common and Eopholidostrophia rare, and within the Shaleriidae the genus Shaleria is revised and found to be the only genus within the family Shaleriidae and to contain three subgenera, S. (Shaleria), S. (Shaleriella) and S. (Janiomya). In the Strophonellidae Strophonella was widespread and Eostrophonella rare. Within the Orthotetoidea, Coolinia and Morinorhynchus(with the new Ludlow and Pridoli species M. rubeli from the Lithuanian boreholes erected) are common, and Fardenia, Saughina, and Valdaria again only known from the west Baltic. Most of the genera and many of the speciesreviewed were very widespread and many found in the adjacent Avalonia and Laurentia: a few were even more cosmopolitan.
Źródło:
Acta Palaeontologica Polonica; 2004, 49, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Osteological correlates for quadrupedality in ornithischian dinosaurs
Autorzy:
Maidment, S.C.R.
Barrett, P.M.
Powiązania:
https://bibliotekanauki.pl/articles/20234.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
The evolution of quadrupedality from bipedal ancestors is an exceptionally rare transition in tetrapod evolution, but it has occurred several times within the herbivorous dinosaur clade Ornithischia. Stegosauria, Ankylosauria, and Ceratopsidae are all uncontroversially quadrupedal, while basal ornithischians and basal ornithopods are uncontroversially bipedal. However, stance in iguanodontian ornithopods, including the hadrosaurs, and in non-ceratopsid ceratopsians is debated because robust osteological correlates of quadrupedality have not been identified. We examine a suite of characteristics that have been previously proposed as osteological correlates for bipedality or quadrupedality in dinosaurs. These include both discrete anatomical features, which we assess as correlates for quadrupedality using character optimization onto a composite cladogram, and proportional ratios, which we assess as correlates by reconstructing nodal ancestral states using squared-change parsimony, followed by optimization. We also examine the correlation of these features with body size. An anterolateral process on the proximal ulna, hoof-shaped manual unguals, a transversely broadened ilium, a reduced fourth trochanter and a femur longer than the tibia are found to be robust correlates of quadrupedality in ornithischian dinosaurs. Along the ceratopsid “stem” lineage, quadrupedal characters were acquired in a stepwise fashion, with forelimb characters developing prior to changes in the hind limb. In contrast, iguanodontid ornithopods display a mosaic of character states, indicating varying degrees of facultative quadrupedality that probably arose for a variety of different reasons. Hadrosaurs are found to possess all character states associated with quadrupedality and were probably predominantly quadrupedal. In general, quadrupedal ornithischians do not appear to have been constrained by their bipedal ancestry to a particular order of character acquisition.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Constraints on the Lamina Density of Laminar Bone Architecture of Large-Bodied Dinosaurs and Mammals
Autorzy:
Hofmann, R.
Stein, K.
Sender, P.M.
Powiązania:
https://bibliotekanauki.pl/articles/946035.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
dinosauria
mammalia
bone histology
laminar bone
lamina thickness
lamina density
Opis:
Laminar bone tissue is commonly found in Dinosauria (including birds) and Mammalia. The tissue emerged convergently several times, and its frequent occurrence among amniotes has stimulated researchers to study some of its geometric features. One such feature is lamina thickness or lamina density (LD, expressed as number of laminae per mm). We measured LD in a sample of sauropodomorph dinosaur taxa (basal sauropodomorphs, basal sauropods and Neosauropoda) and compared it with LD of a selection of mammals. LD is relatively constrained within the groups; nonetheless mean sauropodomorph LD differs significantly from mean mammal LD. However, increasing sample size with other dinosaur groups and more perissodactyls and artiodactyls may alter this result. Among sauropods, LD does not change drastically with increasing femur length although a slight tendency to decrease may be perceived. We conclude that the laminar vascular architecture is most likely determined by a combination of structural and functional as well as vascular supply and physiological causes.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 2; 287-294
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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