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Tytuł:
Relationships of the Devonian Strobilepis and related Pensylvanian problematica
Autorzy:
Hoare, R D
Mapes, R H
Powiązania:
https://bibliotekanauki.pl/articles/21828.pdf
Data publikacji:
1995
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Multiplacophora
Pensylwania
skamienialosci
Strobilepis
paleontologia
skleryty
dewon
Opis:
Reinterpretation of the North American Strobilepis spinigera Clarke 1888 from the Devonian and the find of Diadeloplax paragrapsima gen. et sp. n. from the Pennsylvanian provide the basis for the recognition of a new class of uncertain affinity, Multiplacophora. The range of the class is Middle Devonian (Erian) to Pennsylvanian (Morrowan). Multiplacophora differ from the order Hercolepadida and the classes Thambetolepida and Polyplacophora in the number, shape, and arrangement of plates; the presence of large spines; and the complexity of internal canal systems in the plates and spines.
Środkowodewońska Strobilepis należy do najbardziej tajemniczych skamieniałych organizmów młodszego paleozoiku. Autor ilustruje i analizuje muzealne okazy Strobilepis (w tym również identyfikowane niegdyś jako ślimaki i chitony) dowodząc, że poszczególne skleryty ułożone były liniowo na grzbiecie zwięrzecia a więc odmiennie niż morfologicznie i strukturalnie podobne płytki sylurskiej Hercolepas i dewońskiego Protobalanus. Z późnego karbonu stanu New York pochodzą podobne do Strobilepis zestawy sklerytów opisane jako Diadeloplax paragrapsima gen. et sp. n. Dla tych dwu form utworzona została nowa gromada Multiplacophora z rzędem Strobilepida.
Źródło:
Acta Palaeontologica Polonica; 1995, 40, 2; 111-128
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A peculiar faunivorous metatherian from the early Eocene of Australia
Autorzy:
Beck, R.M.D.
Powiązania:
https://bibliotekanauki.pl/articles/945605.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Mammalia
Metatheria
Marsupialia
Sparassodonta
Archaeonothos henkgodthelpi
new species
Eocene
fossil
deposit
paleontology
Australia
Opis:
I describe Archaeonothos henkgodthelpi gen. et. sp. nov., a small (estimated body mass ~40–80 g) tribosphenic metatherian from the early Eocene Tingamarra Fauna of southeastern Queensland, Australia. This taxon, known only from a single isolated upper molar (M2 or M3) is characterised by a very distinctive combination of dental features that, collectively, probably represent faunivorous adaptations. These include: a straight, elevated centrocrista; a metacone considerably taller than the paracone; a wide stylar shelf (~50% of the total labiolingual width of the tooth); reduced stylar cusps; a long postmetacrista; a small and anteroposteriorly narrow protocone; an unbasined trigon; and the absence of conules. Some of these features are seen in dasyuromorphians, but detailed comparisons reveal key differences between A. henkgodthelpi and all known members of this clade. A. henkgodthelpi also predates recent molecular estimates for the divergence of crown-group Dasyuromorphia. Similar dental features are seen in a number of other metatherians, including the South American sparassodonts, Wirunodon chanku from the ?middle–late Eocene Santa Rosa local fauna of Peru, and Kasserinotherium tunisiense from the early Eocene Chambi fauna of Tunisia, although whether A. henkgodthelpi is closely related to any of these taxa is unclear based on available evidence. I therefore refer A. henkgodthelpi to Metatheria incertae sedis. Potential relatives of A. henkgodthelpi are unknown from any other Australian fossil deposit.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 1; 123-129
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Late Paleozoic turrilepadid machaeridians from North America
Autorzy:
Hoare, R D
Mapes, R H
Yancey, T E
Nestell, M K
Powiązania:
https://bibliotekanauki.pl/articles/22000.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fauna kopalna
perm
namur
Ameryka Polnocna
paleozoik
skamienialosci
Turrilepadida
Machaeridia
cechy morfologiczne
paleontologia
skleryty
Opis:
Turrilepadids are not uncommon in late Paleozoic shales being often associated with ostracodes, foraminifers, and minute molluscs. In North America they range from the late Missippian (Chesterian) to early Permian (Leonardian). Sclerites of the inner scleritome row are more common than outer sclerites. Some clusters have been found. Sclerite consists of two layers with the thicker, lower layer penetrated by a transverse tubular structures oriented perpendicular to the sclerite surface, which may represent canals related to the papillae on the inner surface of the sclerite. Turrilepas Lepros sp. n., T. trigoniodes sp. n., T. asketos sp. n., Clarkeolepis alloeospinosa sp. n., and Ambonlepidas petalos gen. et sp. n. are proposed.
Machaeridia (pospolite we wczesnym paleozoiku organizmy o nieustalonych pokrewieństwach) z rzędu Turrilepadida są częstsze w młodszym paleozoiku, niż się dotąd spodziewano. W Ameryce Płn. występują od namuru (Chesterian) do wczesnego permu. Skleryty wewnętrznego rzędu pancerza są z jakichś powodów częstsze w materiale kopalnym. Każdy skleryt składa się z dwu warstw. Wewnętrzna, grubsza warstwa przebita jest licznymi rurkowatymi strukturami prostopadłymi do powierzchni sklerytu, które mogły pierwotnie stanowić kanały.
Źródło:
Acta Palaeontologica Polonica; 1996, 41, 2; 127-145
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new mammal from the Turonian–Campanian (Upper Cretaceous) Galula Formation, southwestern Tanzania
Autorzy:
O’Connor, P.M.
Krause, D.W.
Stevens, N.J.
Groenke, J.R.
MacPhee, R.D.E.
Kalthoff, D.C.
Roberts, E.M.
Powiązania:
https://bibliotekanauki.pl/articles/20223.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
We here establish a new mammaliaform genus and species, Galulatherium jenkinsi (Mammalia), from the Upper Cretaceous Galula Formation in the Rukwa Rift Basin of southwestern Tanzania. This represents the first named taxon of a mammaliaform from the entire Late Cretaceous of continental Afro-Arabia, an interval of 34 million years. Preliminary study of the holotypic and only known specimen (a partial dentary) resulted in tentative assignation to the Gondwanatheria, a poorly known, enigmatic clade of Late Cretaceous–Paleogene Gondwanan mammals (Krause et al. 2003). The application of advanced imaging (μCT) and visualization techniques permits a more detailed understanding of key anatomical features of the new taxon. It reveals that the lower dentition consisted of a large, procumbent lower incisor and four cheek teeth, all of which were evergrowing (hypselodont). Importantly, all of the teeth appear devoid of enamel. Comparisons conducted with a range of Mesozoic and selected Cenozoic mammaliaform groups document a number of features (e.g., columnar, enamel-less and evergrowing teeth, with relatively simple occlusal morphology) expressed in Galulatherium that are reminiscent of several distantly related groups, making taxonomic assignment difficult at this time. Herein we retain the provisional referral of Galulatherium (RRBP 02067) to Gondwanatheria; it is most similar to sudamericids such as Lavanify and Bharratherium from the Late Cretaceous of Madagascar and India, respectively, in exhibiting relatively simple, high-crowned, columnar cheek teeth. Other features (e.g., enamel-less dentition) are shared with disparate forms such as the Late Jurassic Fruitafossor and toothed xenarthrans (e.g., sloths), here attributed to convergence. Revised analyses of the depositional context for the holotype place it as having lived sometime between the late Turonian and latest Campanian (roughly 91–72 million years ago). This enhanced geochronological context helps to refine the palaeobiogeographical significance of Galulatherium among Cretaceous mammals in general and those from Gondwanan landmasses specifically.
Źródło:
Acta Palaeontologica Polonica; 2019, 64, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimating fossil ant species richness in Eocene Baltic amber
Autorzy:
Penney, D.
Preziosi, R.F.
Powiązania:
https://bibliotekanauki.pl/articles/20623.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Fossil insects in amber are often preserved with life-like fidelity and provide a unique insight to forest ecosystems of the geological past. Baltic amber has been studied for more than 300 years but despite the large number of described fossil species (ca. 3500 arthropods) and abundance of fossil material, few attempts have been made to try and quantify statistically how well we understand the palaeodiversity of this remarkable Fossil-Lagerstätte. Indeed, diversity estimation is a relatively immature field in palaeontology. Ants (Hymenoptera: Formicidae) are a common component of the amber palaeobiota, with more than 100 described species representing approximately 5% of all inclusions encountered. Here we apply quantitative statistical species richness estimation techniques to Baltic amber data for the first time. We use species level data from a sample size of 12 769 specimens and conclude that around 29% of the Baltic amber ant fauna has yet to be discovered. The species richness accumulation curve clearly reaches its asymptote at around 9650 specimens, indicating this as the minimum sample size required for a reasonable estimate of species richness for ants alone. Hence, it is hardly surprising that previous studies concerning so-called “representative” samples of the entire palaeobiota, consisting of at most a few thousand inclusions do not agree with each other. Nonetheless, we demonstrate that it is possible to apply quantitative techniques to amber derived data and this should be the preferred approach wherever possible, rather than generating qualitative conclusions of little value for comparative purposes.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reassessment of the late Triassic symmetrodont mammal Woutersia
Autorzy:
Sigogneau-Russell, D
Hahn, R
Powiązania:
https://bibliotekanauki.pl/articles/23476.pdf
Data publikacji:
1995
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
zeby
Woutersia butleri
trias
ssaki
skamienialosci
Woutersia
cynodonty
Woutersiidae
symetrodonty
Francja
paleontologia
Woutersia mirabilis
paleozoologia
morfologia zwierzat
Opis:
Since the creation of the taxon Woutersia mirabilis Sigogneau-Russell 1983, on a lower molar and two upper molars from the French locality of Saint-Nicolas-de-Port (late Triassic), quite a number of additional mammalian teeth have come to light; among them, are not only some elements undoubtedly belonging to this species, but also 5 teeth interpreted here as representing a second species of Woutersia, W. butleri sp. n. The peculiarities of this second species, especially in the upper molars, allow in turn the presentation and discussion of another upper molar from the same locality, which had remained an enigma for a long time. Though too large to be attributed to W. butleri, this tooth exhibits at a higher degree some characters already detected in the latter species, suggesting that it could still belong to Woutersia: but in that case, its sharing of some derived characters with upper molars of docodonts implies at least a certain parallelism between the new family Woutersiidae and primitive Docodonta.
Nowe znaleziska izolowanych zębów retyckich Synapsida ze stanowiska Saint-Nicolas-de-Port we Francji, obok licznych Haramiyidae i cynodontów, dostarczyły nowych okazów symetrodontów. Pozwalają one na uzupełnienie diagnozy typowego gatunku rodzaju Woutersia, W. mirabilis i wydzielenie nowego gatunku W. butleri oraz rodziny Woutersiidae wykazującej paralelizmy w morfologii górnych zębów do późniejszych symetrodontów a także specjalizacje do funkcji miażdżenia w pokroju trzonowców.
Depuis la création du taxon Woutersia mirabilis Sigogneau-Russell 1983 (Mammalia, Theria), sur une molaire inférieure et deux molaires supérieures en provenance du gisement français de Saint-Nicolas-de-Port (Trias supérieur), un grand nombre de dents mammaliennes supplémentaires ont été mises au jour. Parmi celles-ci se trouvent non seulement quelques éléments appartenant indubitablement à cette espéce, mais aussi 5 dents interprétées ici comme représentant une seconde espèce de Woutersia, W. butleri sp. n. Les particularités de cette seconde espéce, spécialement au niveau des molaires supérieures, ont à leur tour permis d'interpréter une autre molaire supérieure du même gisement restée longtemps une énigme. Cette dent, dont la morphologie exagère certains caractères décelés chez W. butleri, tout en étant beaucoup trop grande pour cette espèce, pourrait cependant appartenir au même genre; mais, si cette attribution est exacte, le partage de certains caractères dérivés avec les dents supérieures de Docodontes implique au moins un certain parallélisme entre la nouvelle famille Woutersiidae et les Docodontes primitifs.
Źródło:
Acta Palaeontologica Polonica; 1995, 40, 3; 245-260
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research history, taphonomy, and age structure of a mass accumulation of the ornithopod dinosaur Dysalotosaurus lettowvorbecki from the Upper Jurassic of Tanzania
Autorzy:
Hubner, T.R.
Foth, C.
Heinrich, W.-D.
Schwarz, D.
Bussert, R.
Powiązania:
https://bibliotekanauki.pl/articles/2082333.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Crocodylomorpha
Thalattosuchia
Metriorhynchidae
Lower Cretaceous
Valanginian
Czech Republic
Opis:
Metriorhynchid crocodylomorphs were an important component in shallow marine ecosystems during the Middle Jurassic to Early Cretaceous in the European archipelago. While metriorhynchids are well known from western European countries, their central and eastern European record is poor and usually limited to isolated or fragmentary specimens which often hinders a precise taxonomic assignment. However, isolated elements such as tooth crowns, have been found to provide informative taxonomic identifications. Here we describe two isolated metriorhynchid tooth crowns from the upper Valanginian (Lower Cretaceous) of the Štramberk area, Czech Republic. Our assessment of the specimens, including multivariate analysis of dental measurements and surface enamel structures, indicates that the crowns belong to two distinct geosaurin taxa (Plesiosuchina? indet. and Torvoneustes? sp.) with different feeding adaptations. The specimens represent the first evidence of Metriorhynchidae from the Czech Republic and some of the youngest metriorhynchid specimens worldwide.
Źródło:
Acta Palaeontologica Polonica; 2021, 66, 2; 357-367
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New sharks and rays from the Cenomanian and Turonian of Charentes, France
Autorzy:
Vullo, R
Cappetta, H.
Neraudeau, D.
Powiązania:
https://bibliotekanauki.pl/articles/20707.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Turonian
Neoselachii
marine environment
Cenomanian
rajiform
Cretaceous
Rajiformes
taxonomy
Chondrichthyes
paleoenvironment
orectolobiform
Orectolobiformes
lamniform
new taxonomy
France
deposit
Lamniformes
Charente department
coastal environment
paleontology
Opis:
New or so far poorly known neoselachians from the Cenomanian and Turonian of SW France are described. The material studied herein comes from nine localities in the Charentes region, comprising palaeoenvironments ranging from coastal to open marine environments, and consists of two orectolobiforms, six lamniforms, and four rajiforms. The new taxa are Squalicorax coquandi sp. nov. and Roulletia bureaui gen. et sp. nov. within lamniforms, and Hamrabatis bernardezi sp. nov., Archingeayia sistaci gen. et sp. nov., and Engolismaia couillardi gen. et sp. nov. within rajiforms. New specimens of Odontaspis rochebrunei Sauvage, 1880 from the type area allow redescription of this taxon, assigned herein to the genus Cenocarcharias. Occurrences of Squalicorax baharijensis, S. cf. intermedius, and Archaeolamna sp., previously unrecorded from this region, and Almascyllium, a genus generally described from younger strata, are also noted, and improve knowledge of mid−Cretaceous selachian faunas from Western Europe.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The first giant titanosaurian sauropod from the Upper Cretaceous of North America
Autorzy:
Fowler, D.W.
Sullivan, R.M.
Powiązania:
https://bibliotekanauki.pl/articles/22113.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Argentinosaurus(Cenomanian, Argentina) is generally accepted as being the largest dinosaur so far discovered and is one of several giant titanosaurian sauropods known from the Upper Cretaceous of South America and Asia, but surprisingly not from North America. Here we present the first evidence of giant titanosaurian sauropods from the Upper Cretaceous of North America: two enormous vertebrae and a partial femur, from the Naashoibito Member of the Ojo Alamo Formation, New Mexico, and referred to Alamosaurus sanjuanensis. One of the new vertebrae, a posterior cervical, is comparable in size to a posterior cervical described for Puertasaurus: an Argentinosaurus−sized titanosaurian from the Maastrichtian of Argentina. This makes A. sanjuanensisthe largest dinosaur from North America, and among the largest in the world. These findings indicate that A. sanjuanensis is diagnosed based on immature remains, which may have implications for cladistic analyses.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The endocranium of the theropod dinosaur Ceratosaurus studied with computer tomography
Autorzy:
Sanders, R K
Smith, D.K.
Powiązania:
https://bibliotekanauki.pl/articles/22430.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
cranial pneumatic system
Ceratosaurus
virtual rendering
paleoneurology
Theropoda
theropod dinosaur
computer tomography
dinosaur
endocranium
paleontology
Opis:
A well preserved specimen of the theropod Ceratosaurusfrom the Upper Jurassic Morrison Formation of western Colorado was recently described and given the name C. magnicornis. The systematics of the genus is outside the scope of the present study but, as a generally accepted basal tetanuran, the braincase was CT scanned to provide a description of the endocranium, inner ear, pneumatic, and venous sinus systems in a primitive member of this clade. Five major subregions of the theropod endocranium are distinguished for the purpose of simplifying cranial computed tomographic interpretation and to provide a systematic means of comparison to other endocrania. The skull morphology of Ceratosaurus influences the overall braincase morphology and the number and distribution of the major foramina. The low pontine angle and relatively unflexed braincase is considered a more primitive character. The orientation of the horizontal semicircular canal confirms a rather horizontal and unerect posture of the head and neck. As in birds, the narrower skull morphology of Ceratosaurusis associated with fewer cranial nerve foramina. Additionally, the maxillary dominated dentigerous upper jaw of Ceratosaurusis felt to share with the alligator a large rostrally directed maxillary division of the trigeminal nerve and a small ophthalmic branch. The upper bill of birds, being dominated by the premaxillary and lacking teeth, is innervated predominantly by the ophthalmic division of the trigeminal nerve. For this reason, avian−based cranial nerve reconstructions are felt to be inappropriate for basal theropods.Ceratosaurusskull pneumatization and possible evidence of olfactory conchal structures is on the other hand very avian in character. Based on computed tomography, Ceratosaurusis determined to have possessed a typical basal theropod endocranium and bipedal vestibular system similar to Allosaurus.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two new stegosaur specimens from the Upper Jurassic Morrison Formation of Montana, USA
Autorzy:
Woodruff, D.C.
Trexler, D.
Maidment, S.C.R.
Powiązania:
https://bibliotekanauki.pl/articles/21465.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Two partial skeletons from Montana represent the northernmost occurrences of Stegosauria within North America. One of these specimens represents the northernmost dinosaur fossil ever recovered from the Morrison Formation. Consisting of fragmentary cranial and postcranial remains, these specimens are contributing to our knowledge of the record and distribution of dinosaurs within the Morrison Formation from Montana. While the stegosaurs of the Morrison Formation consist of Alcovasaurus, Hesperosaurus, and Stegosaurus, the only positively identified stegosaur from Montana thus far is Hesperosaurus. Unfortunately, neither of these new specimens exhibit diagnostic autapomorphies. Nonetheless, these specimens are important data points due to their geographic significance, and some aspects of their morphologies are striking. In one specimen, the teeth express a high degree of wear usually unobserved within this clade—potentially illuminating the progression of the chewing motion in derived stegosaurs. Other morphologies, though not histologically examined in this analysis, have the potential to be important indicators for maturational inferences. In suite with other specimens from the northern extent of the formation, these specimens contribute to the ongoing discussion that body size may be latitudinally significant for stegosaurs—an intriguing geographical hypothesis which further emphasizes that size is not an undeviating proxy for maturity in dinosaurs.
Źródło:
Acta Palaeontologica Polonica; 2019, 64, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The curvature-transition series: integral part of some simple-cone conodont apparratuses (Panderodontacea, Distacodontacea, Conodontata)
Szeregi przemian zagięcia jako integralne części pewnych pierwotnych aparatów konodontowych (Panderodontacea, Distacodontacea, Conodontata)
Autorzy:
Fahraeus, L.E.
Hunter, D.R.
Powiązania:
https://bibliotekanauki.pl/articles/20595.pdf
Data publikacji:
1985
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Elements of species of Drepanoistodus Lindström, Panderodus Ethington, and Protopanderodus Lindström systematically vary from symmetrical to pronouncedly asymmetrical (symmetry-transition series) within each species, and a group of elements with systematic increase in curvature of the cusp can be recognized for each element type; each such group is named a curvature-transition series. Panderodus and Protopanderodus, both of the Panderodontacea, have essentially identical apparatuses with regard to symmetry and curvature-transition series whereas Drepanoistodus, of the Distacodontacea, differs in type of symmetry-transition series and number of curvature-transition series. The curvature-transition series is considered to represent a taxonomically distinct character at the suprageneric level.
W zespołach elementów każdego z gatunków konodontów z rodzajów Drepanoistodus Lindström, Panderodus Ethington i Protopanderodus Lindström objawia się zmienność stopnia asymetrii elementów i stopnia zagięcia ich zębów. W obrębie szeregów przemian symetrii (symmetry-transition series) identyfikuje się odrębne typy elementów, symetryczne i asymetryczne — o rosnącym stopniu asymetrii. Proponujemy wprowadzenie nowego pojęcia szeregów przemian zagięcia (curvature-transition series) obejmujących formy elementów o wzrastającym stopniu zagięcia zęba w obrębie każdego z członów szeregu przemian symetrii. Spośród rozpatrywanych rodzajów, rodzaje Panderodus i Protopanderodus (obydwa z nadrodziny Panderodontacea) obejmują aparaty o zasadniczo podobnych szeregach przemian symetrii i zagięcia, podczas kiedy Drepanoistodus (Distacodontacea) ma odmienny typ szeregu przemian symetrii i inną liczbę szeregów przemian zagięcia. Uważamy szeregi przemian zagięcia za odrębny rodzaj charakterystyki taksonomicznej jednostek rangi ponadrodzajowej.
Źródło:
Acta Palaeontologica Polonica; 1985, 30, 3-4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The extent of the pterosaur flight membrane
Autorzy:
Elgin, R.
Hone, D.
Frey, E.
Powiązania:
https://bibliotekanauki.pl/articles/23515.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Reptilia
Pterosauria
flight
wing
Mesozoic
pterosaur
wing membrane
fossil
Opis:
The shape and extent of the membranous brachioptagium in pterosaurs remains a controversial topic for those attempting to determine the aerodynamic performance of the first vertebrate fliers. Various arguments in favour of the trailing edge terminating against either the torso or hip, the femur, the ankle, or different locations for various taxa, has resulted in several published reconstructions. Uncertainty over the correct model is detrimental to both aerodynamic and palaeoecological studies that are forced to simultaneously consider multiple and highly variable configurations for individual taxa. A review of relevant pterosaur specimens with preserved soft tissues or impressions of the wing membrane, however, strongly suggests that the trailing edge of the wing extended down to the lower leg or ankle in all specimens where the brachiopatagium is completely preserved. This configuration is seen across a phylogenetically broad range of pterosaurs and is thus likely to have been universally present throughout the Pterosauria. Support for opposing hypotheses where the trailing edge terminates against the body, hip, or knee are based on several specimens where the wing membrane is either incomplete or has undergone post−mortem contraction. An ankle attachment does not rule out a high aspect ratio wing as the curvature of the trailing edge and the ratio of the fore to hind limbs also play a major role in determining the final shape of the membrane.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Virtual 3D modeling of the ammonoid conch to study its hydrostatic properties
Autorzy:
Moron-Alfonso, D.A.
Peterman, D.J.
Cichowolski, M.
Hoffmann, R.
Lemanis, R.E.
Powiązania:
https://bibliotekanauki.pl/articles/2082232.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Cephalopoda
Ammonoidea
virtual modeling
3D
conch
CT-scan
morphometry
Cretaceous
Antarctica
Opis:
Computed tomography has provided a wealth of biological data that now stands beside a vast, more traditional, morphometric database. By exploiting these two resources, we present a novel methodology to construct intricate, virtual cephalopod shells. As a case of study, we applied this method to Maorites seymourianus using data obtained from a previous work. For this purpose, evaluation of the conch geometry, and the definition of new parameters such as the segment width expansion rate (SWER), segment height expansion rate (SHER), the segment thickness expansion rate (STER), and three indices related, were introduced. The conch geometry of M. seymourianus follows a spiral that can be defined by a polynomial function. While similar to a logarithmic function, a polynomial fit is preferred because it reveals higher values of whorl expansion at the early ontogenetic phase and lower values reaching the adult body chamber. Results on the hydrostatic properties of the virtual models indicate that M. seymourianus would have a near neutral buoyancy, ranging from slightly positive to slightly negative, depending upon parameters that influence organismal mass. Positions of the center of mass and the center of buoyancy indicate that the studied species would have a relatively low hydrostatic stability, estimating a shell orientation of approximately 74–76° with respect to the vertical, with the aperture slightly inclined downwards relative to the horizontal plain.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 3; 467-480
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dietary ecology of the extinct cave bear: evidence of omnivory as inferred from dental microwear textures
Autorzy:
JONES, D. BRENT
DESANTIS, LARISA R.G.
Powiązania:
https://bibliotekanauki.pl/articles/945458.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
mammalia
ursus spelaeus
carnivore
dental microwear
pleistocene
europe
Opis:
The diet of the extinct European cave bear, Ursus spelaeus, has widely been debated. Diverging from the extant brown bear (Ursus arctos) approximately 1.2 million years ago, the cave bear is one of the most ubiquitous fossil bears occurring in Europe during the Middle and Late Pleistocene. Early morphological studies suggested that the cave bear was likely specialized on processing tough and/or abrasive foods, while later two-dimensional low-magnification microwear studies suggested that they were omnivorous and may have consumed more bone than U. arctos. Here, we used dental microwear texture analysis (DMTA) to further interpret the diet of the cave bear. Microscopic wear features were assessed and compared to modern ursids, including the cave bears’ closest living relative, U. arctos. Results suggest that U. spelaeus consumed a diet with a diversity of textural properties, similar to most other bears and only distinguishable from the hyper-carnivorous polar bear (Ursus maritimus). Further, only U. maritimus can be distinguished from all bear species here examined (i.e., the giant panda bear, Ailuropoda melanoleuca; sun-bear, Ursus malayanus; spectacled bear, Tremarctos ornatus; American black bear, Ursus americanus; and U. arctos), with significantly greater area-scale fractal complexity (Asfc) of microwear surfaces. The DMTA of A. melanoleuca also has significantly lower Asfc than T. ornatus and U. americanus, consistent with observed dietary behavior. As modern bears vary their diets seasonally and across their range, it may be difficult to characterize the dietary ecology of extinct bears using dental microwear alone. Nevertheless, DMTA here demonstrates that U. spelaeus had a diet distinct from the hyper-carnivorous U. maritimus and instead likely consumed food with textural properties most similar to other herbivorous/omnivorous bears. Lastly, the European cave bear and North American giant short-faced bear (Arctodus simus) may have had similar diets as evident from DMTA, with U. spelaeus potentially eating tougher food items.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 4; 735-741
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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