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Tytuł:
On the morphology and evolution of the Cucullograptinae (Monograptidae, Graptolithina)
Morfologia i ewolucja Cucullograptinae (Monograptidae, Graptolithina)
Morfologija i ehboljucija Cucullograptinae (Monograptidae, Graptolithina)
Autorzy:
Urbanek, A.
Powiązania:
https://bibliotekanauki.pl/articles/22204.pdf
Data publikacji:
1966
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
morphology
evolution
Cucullograptinae
Monograptidae
Graptolithina
paleontology
terminology
systematics
Źródło:
Acta Palaeontologica Polonica; 1966, 11, 3-4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The PhyloCode, or alternative nomenclature: Why it is not beneficial to palaeontology, either
Autorzy:
Monsch, K.A.
Powiązania:
https://bibliotekanauki.pl/articles/23327.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
nomenclature
paleontology
Phylocode name
phylogenesis
systematics
taxonomy
Opis:
Methodological stability in biological nomenclature is being upset recently, with potential consequences for palaeontology. Some systematists, inspired mainly by de Queiroz and Gauthier (1990, 1992, 1994), reject traditional nomenclature in favour of an alternative “Phylogenetic Nomenclature” (PN). Following de Queiroz (2006) I consistently call this Phylogenetic Nomenclature, rather than Phylogenetic taxonomy, as it is often done. Important tenets of PN are the abandonment of hierarchic ranks and binomial names, and establishing name definitions based on cladogram shape (node−, stem−, and stem−modified node−based definitions), apomorphies (apomorphy−based definitions), or a combination of apomorphies and tree topology (apomorphy−modified node−based definition). For an explanation of such definitions, see Cantino and de Queiroz (2003) and Sereno (2005). The practice of Phylogenetic Nomenclature is laid out in an Internet document, the PhyloCode (Cantino and de Queiroz 2003). PN is seen as the natural next step in the evolution of taxonomy: from Linnaeus’ (1753, 1758) “creationist taxonomy” to Hennig’s (1966) cladistic taxonomy. Hence, Linnaeus’ ideas should be removed from nomenclature, which will then reflect phylogeny. Despite the dominance of cladistics as a framework for taxonomy, the validity of its philosophies and methodologies are still questioned (e.g., Szalay 2000). I encourage everyone, independently of school of taxonomy adhered to, to take interest in PN, because: (1) we are all creators or users of taxonomies and classifications, (2) PN is radically different from the current standard, (3) the Preface to the PhyloCode suggests it should ultimately replace the current Codes of Nomenclature (of bacteria, LaPage et al. 1992; of Zoology, ICZN 1999; of Botany, Greuter et al. 2000). I argue herein, why palaeontologists should not follow PN.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new genus of "miacid" carnivoran from the earliest Eocene of Europe and North America
Autorzy:
Smith, T.
Smith, R.
Powiązania:
https://bibliotekanauki.pl/articles/21490.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
new genus
Carnivora
systematics
Gracilocyon
Eocene
Europe
North America
Opis:
“Miacid” carnivorans comprise one of the modern mammal groups appearing around the Palaeocene–Eocene Thermal Maximum (PETM) in the Northern Hemisphere. Here we describe a new very small “miacid” carnivoran from the earliest Eocene of Dormaal, Belgium, that shares a particular dental morphology with the species “Miacis” winkleri and “Miacis” rosei from the early Eocene of North America. The three species present very gracile and sharp teeth, and are hereby placed in the new genus Gracilocyon. Comparative dental analysis of Gracilocyon with other early “miacids” contributes to better resolve the polarity of dental characters and indicates that this genus is one of the most primitive members of the family. Diversity of early modern carnivorans is greater than previously considered and early “miacids” seem to have dispersed into North America from two different geographic origins.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New remains attributable to the holotype of the sauropod dinosaur Neuquensaurus australis, with implications for saltasaurine systematics
Autorzy:
D'emic, M.
Wilson, J.
Powiązania:
https://bibliotekanauki.pl/articles/20033.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Dinosauria
Sauropoda
Titanosauria
Neuquensaurus australis
Saltasaurus loricatus
taxonomy
Cretaceous
South America
remains
new remains
holotype
sauropod dinosaur
dinosaur
systematics
saltasaurine systematics
Opis:
The Late Cretaceous South American sauropods Neuquensaurus australis and Saltasaurus loricatus are represented by well−preserved and abundant material that has been integral to our understanding of titanosaur anatomy for decades. Although the hypodigms for these species span most of the skeleton, holotypic materials are limited to a few bones that do not overlap between the two taxa. In this contribution, we augment the holotype of Neuquensaurus australis with a partial sacrum that was preserved in articulation with one of the caudal vertebrae from its original description, but not recognised as such at the time. We document this field association via the presence of a broken piece of matrix on the sixth sacral vertebral centrum that has a snap−fit to matrix on the rim of the anterior condyle of the holotypic biconvex vertebra. Based on comparisons with a more complete sacrum and ilium of a referred specimen of Neuquensaurus australis, we interpret this biconvex vertebra to be the seventh sacral vertebra. This raises the possibility that the biconvex “first caudal” vertebra of some other titanosaurs may be part of the sacrum as well. Augmentation of the Neuquensaurus australis holotype to include a sacrum makes it directly comparable to the holotype of Saltasaurus loricatus. Morphological differences in the number, shape, and proportion of sacral vertebrae allow discrimination between Neuquensaurus and Saltasaurus, confirming their generic separation. The El Brete quarry, which preserves the holotypic sacrum and abundant referred specimens of Saltasaurus loricatus, also preserves a sacrum consisting of seven vertebrae that bears autapomorphies of Neuquensaurus australis, indicating that these two saltasaurines coexisted.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early Cretaceous symmetrodont mammal Gobiotheriodon from Mongolia and the classification of Symmetrodonta
Autorzy:
Averianov, A O
Powiązania:
https://bibliotekanauki.pl/articles/20946.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Gobiotheriodon infinitus
systematics
classification
Early Cretaceous
mammal
Cretaceous
Mongolia
Gobiotheriodon
paleontology
Opis:
The “symmetrodont” mammal, Gobiotheriodon infinitus (Trofimov, 1980), from the Early Cretaceous (Aptian–Albian) of Mongolia, is redescribed.The species is restricted to the holotype only (dentary with three last molars), the referred maxillary fragment with M3? is considered here as cf. Gobiconodon sp.The dental formula of G. infinitusis reinterpreted as i1–3 c1 p1–3 m1–4. G. infinitus is characterized by a short dentary symphysis; long, well−developed Meckel's groove; small, triangular−shaped pterygoid fossa; weakly developed pterygoid crest; i3 enlarged; p1–3 two−rooted; lower molars acute− to obtuse−angled, labial cingulids lacking, lingual cingulids very short, well developed mesial and distal cingulid cuspules (“e” and “d”) and prominent wear surface on the paracristid. Gobiotheriodon is similar to Tinodon (Late Jurassic, USA; Early Cretaceous, Great Britain and Portugal) in postcanine dental formula and structure of the pterygoid fossa; it is provisionally assigned to Tinodontidae Marsh, 1887.Some taxa previously assigned to (or suggested as possible relatives of) “Symmetrodonta” are reviewed.Amphidontidae Simpson, 1925 is considered as nomen dubium.A new classification for “Symmetrodonta” is proposed.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Phylocode: Beating a dead horse?
Autorzy:
Benton, M J
Powiązania:
https://bibliotekanauki.pl/articles/22908.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
systematics
Phylocode concept
stability
Phylocode name
Linnaean rank
paleontology
Linnaean system
Opis:
The concept of the Phylocode has been evolving for some twenty years, and is supported by Lee and Skinner (2007): I argue against it here. The first issue is stability, and biologists must decide whether they seek rigidity (Phylocode) or flexibility and conservativeness of clade contents (Linnaean codes). Phylocode names for taxa are by definition stable because they are established as labels for clades that are rigidly defined as geometric constructs. But this is not real stability because the species contained within those clades can change dramatically: an example is given where Phylocode practice forces a decision about the name Deinonychosauria, which can contain 20 or 10,000 species depending on which current tree is correct. Linnaean systems offer real stability (= conservativeness + flexibility) where the taxon name can be moved subtly up and down nodes in a tree to keep its association with a particular character or group of species. Proponents of the Phylocode argue that category/rank terms should be dispensed with, and yet they have no need to do this. Everyone accepts that Linnaean ranks are subjective, and yet there is no benefit in abandoning ranks because they have proved to be of such value to users of classifications, and genera and families, for example, act as valuable surrogates for species in large−scale evolutionary and ecological studies. Finally, the Phylocode extends regulation beyond names and their proper use into determining the validity of phylogenetic hypotheses, and this will act as a limit on normal scientific debate.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A revision of 'pediomyid' marsupials from the Late Cretaceous of North America
Autorzy:
Davis, B M
Powiązania:
https://bibliotekanauki.pl/articles/23172.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fauna
systematics
mammal
Canada
Late Cretaceous
marsupial
Marsupialia
North America
paleontology
Opis:
“Pediomyids” are a diverse group of smallto medium−sized marsupials which comprise a significant portion of many Late Cretaceous North American mammalian faunas. Known almost exclusively from isolated teeth and jaw fragments, “pediomyids” exhibit far more diversity than any other contemporaneous group of North American mammals. This has led some to suggest that the family “Pediomyidae” is an artificial, polyphyletic assemblage composed of multiple lineages that independently acquired various traditionally−recognized “pediomyid” molar characters, such as a reduction of the anterior stylar shelf, reduction of the stylocone and a labial shift in the attachment of the cristid obliqua. The present study seeks to elucidate the interrelationships of “pediomyid” marsupials and test the monophyly of the group using cladistic methodology, including a broad sampling of Late Cretaceous North American taxa and a comprehensive set of qualitative molar characters. Results suggest that the family “Pediomyidae” and the genus “Pediomys” are both polyphyletic and are in need of systematic revision. Iqualadelphis lactea (Aquilan) appears to be unrelated to the “pediomyid” radiation, and rests as a stem taxon near the base of the cladogram. The large Aquilan Aquiladelphis nests in a trichotomy with a strictly−defined “Pediomyidae” and the enigmatic Lancian taxon Glasbius, suggesting the possibility of a distant relationship (above the familial level). Three clades are recognized within the “Pediomyidae”: a restricted Pediomys, Leptalestes gen. nov. (containing the three smallest species), and Protolambda (containing the remaining three larger species). Results suggest that “Pediomys” exiguus is a stem taxon lacking a close relationship to Pediomyidae sensu stricto, and is removed to permit recognition of the family as monophyletic. The results carry implications for the role “pediomyids” might have played in the initial North American marsupial radiation sometime prior to the Campanian, and the pattern of molar evolution throughout major Late Cretaceous lineages.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morfologia kontra molekuły - o konflikcie pomiędzy hipotezami filogenetycznymi na przykładzie łuskonośnych
Morphology versus molecules - on the conflict between phylogenetic hypotheses in squamate reptiles
Autorzy:
Skawiński, Tomasz
Kaczmarek, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/1034165.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Przyrodników im. Kopernika
Tematy:
paleontology
reptiles
squamate evolution
systematics
DNA
ewolucja
gady
paleontologia
systematyka
Opis:
Łuskonośne to jedna z największych grup współczesnych kręgowców. Przez wiele lat jej systematyka wydawała się dobrze ustalona, jednak zaawansowane badania molekularne prowadzone w XXI wieku sugerują zupełnie odmienny jej obraz. Tradycyjne dane morfologiczne wskazują, że łuskonośne obejmują dwie główne grupy - Iguania i Scleroglossa. Z kolei według badań molekularnych Iguania są zagnieżdżone głęboko wewnątrz Scleroglossa i blisko spokrewnione z zupełnie odmiennymi morfologicznie waranami, padalcami, czy wężami. Wskazywałoby to na ogromną konwergencję w morfologii lub sekwencjach genów pomiędzy różnymi grupami łuskonośnych i ich krewnych.
Squamates are one of the largest groups of extant vertebrates. For many years, their systematics seemed to be well established, yet comprehensive molecular genetics analyses conducted in the XXI century suggest completely different picture of the squamate phylogeny. Traditional morphological data suggest that squamates comprise two main groups - iguanians and scleroglossans. However, molecular data imply that iguanians are deeply nested within Scleroglossa and most closely related to squamates of strikingly different morphology such as monitor lizards, slow worms and snakes. This would suggest a huge amount of convergence either in morphology or gene sequences between many groups of squamates and their closest relatives.
Źródło:
Kosmos; 2017, 66, 2; 253-259
0023-4249
Pojawia się w:
Kosmos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new giant discinoid brachiopod from the Lower Devonian of Algeria
Autorzy:
Mergl, M
Massa, D.
Powiązania:
https://bibliotekanauki.pl/articles/22683.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
systematics
new brachiopod
brachiopod
Devonian
Algeria
Lower Devonian
Germany
Discinoidea
Brachiopoda
paleontology
Opis:
A new discinoid brachiopod Gigadiscina gen. nov., with the type species G. lessardi sp. nov., is described from the Lower Devonian (Siegenian) of the Tamesna Basin (South Ahaggar Massif, South Algeria). It is characterised by large size and convexo−planar profile of the shell, with a subcentral pedicle foramen. Micro−ornament is typically discinoid, with small circular pits in radial rows on the post−larval shell surface. Related species of Malvinokaffric Realm origin from South Africa, Falkland Islands, Antarctica, South America, and Libya are reviewed, including the poorly known Discina anomala from the Lower Devonian of Germany. The giant size and convexo−planar shells of these discinoids, remarkably similar to recent limpets, are interpreted as adaptation to a habitat in proximity of sandy and gravel beaches in a high−energy environment. Most likely, the conical dorsal valve suppressed drag in turbulent waters, whereas fixation of shell by large, sucker−like pedicle eliminated peeling from the substrate.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The pustulated temnospondyl revisited - a plagiosternine plagiosaurid from the Lower Triassic of Brasil
Autorzy:
Dias-Da-Silva, S
Milner, A.R.
Powiązania:
https://bibliotekanauki.pl/articles/23465.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
temnospondyl
plagiosternine plagiosaurid
Lower Triassic
Triassic
paleontology
Brazil
plagiosaurid
systematics
morphology
Opis:
A recent contribution published in this journal (Dias−daSilva and Ilha 2009) reported a dermal skull fragment indicating the presence of a putative plagiosauroid temnospondyl in the Lower Triassic Sanga do Cabral Formation of the Paraná Basin, Southern Brazil. The taxonomic assignation of this specimen was necessarily tentative as it was based on circumstantial evidence, specifically the presence of a dense pustular ornamentation over four partial dermal skull bones, consideration of the described taxa known to bear such ornamentation, and the stratigraphic and paleobiogeographic range of such taxa. Therefore, Diasda−Silva and Ilha (2009) could not be totally certain about the plagiosauroid affinities of the new specimen and ascribed it to ?Plagiosauridae. It was particularly difficult to make a precise osteological identification of the specimen and six alternative osteological interpretations were made in comparison to both Gerrothorax and Peltobatrachus (see Dias−da−Silva and Ilha 2009: fig. 2). In spite of the poor taxonomic resolution, the new specimen raised interesting questions regarding the presence of plagiosauroid stereospondyls in western Gondwana, as well as their evolutionary patterns, biostratigraphic and paleobiogeographic implications. After Dias−da−Silva and Ilha's (2009) contribution was published, new data from Damiani et al. (2009) raised the possibility of narrowing down the taxonomic identity of the plagiosauroid from Brazil. Accordingly, this brief report provides a more precise taxonomic assignation for this material.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 3; 561-563
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gladius shape variation in coleoid cephalopod Trachyteuthis from the Upper Jurassic Nusplingen and Solnhofen Plattenkalks
Autorzy:
Fuchs, D
Engeser, T.
Keupp, H.
Powiązania:
https://bibliotekanauki.pl/articles/21066.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
gladius
Cephalopoda
systematics
variation
Vampyropoda
coleoid cephalopod
morphology
Trachyteuthis
paleontology
phylogenetic implication
Coleoidea
Opis:
Although the fossil record of coleoid cephalopods is generally poor, the Upper Jurassic Nusplingen and Solnhofen Plattenkalks have provided numerous well−preserved coleoids. Trachyteuthis hastiformis, a comparatively large vampyropod coleoid, was previously known to represent the sole species of its genus in Nusplingen and Solnhofen. However, morphological comparisons based on 50 specimens from different museum collections revealed two additional species: T. nusplingensis sp. nov. and T. teudopsiformis sp. nov. Both species lack the distinct spindle−shaped elevation on the gladius median field typical for T. hastiformis. T. nusplingensis sp. nov. is clearly characterised by a smooth median field and a more or less regular granulation on the dorsal gladius surface, whereas T. teudopsiformis sp. nov. can be easily distinguished by the presence of a Teudopsis−like median keel and an extremely narrow granulation. Morphometric analyses have shown that length−width indices are ambiguous characters to differentiate between the three species. Phylogenetically, the keeled and anteriorly pointed T. teudopsiformis sp. nov. can be linked with the Early Jurassic genus Teudopsis and the Late Cretaceous genus Glyphiteuthis.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New dryolestidan mammal from the Hauterivian–Barremian transition of the Iberian Peninsula
Autorzy:
Cuenca−Bescos, G.
Badiola, A.
Canudo, J.I.
Gasca, J.M.
Moreno-Azanza, M.
Powiązania:
https://bibliotekanauki.pl/articles/21671.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
dryolestidan mammal
Hauterivian–Barremian
Iberian Peninsula
paleontology
Mammalia
Cladotheria
Dryolestida
Crusafontia
systematics
Cretaceous
Opis:
Crusafontia amoae sp. nov. (Dryolestida, Stem Cladotheria) is represented by two isolated upper molars (M4 or M5 and M6 or M7) from the terminal Hauterivian–basal Barremian (Early Cretaceous) of the El Castellar Formation (Galve, Spain). The molars have a deep ectoflexus, a distinct metacone, a continuous metacrista, and an antero−lingually placed paracone. They differ from the molars of the other species of the genus, Crusafontia cuencana, by their larger size, by their outsized parastyle, by the pointed lingual slope of the paracone, their more symmetrical appearance with a deep ectoflexus in occlusal view, and the well−developed metacone. Revision of three isolated teeth previously attributed to Crusafontia cuencana suggests that instead of being upper premolars belonging to Crusafontia cuencana they in fact belong to Pocamus pepelui, of the stem cladotherian superorder Zatheria, probably “peramuran”. As such, the stem Cladotheria record from the Early Cretaceous of the Iberian Peninsula is composed of two dryolestids (Crusafontia amoae and Crusafontia cuencana) and one zatherian (Pocamus pepelui).
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Systematic and biostratigraphic significance of a chinchillid rodent from the Pliocene of eastern Argentina
Autorzy:
Rasia, L.L.
Candela, A.M.
Powiązania:
https://bibliotekanauki.pl/articles/22264.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
systematics
biostratigraphy
significance
chinchillid rodent
rodent
Mammalia
Rodentia
Caviomorpha
Chinchillidae
paleontology
Pliocene
Argentina
Opis:
Two species of chinchillid rodents, Lagostomus (Lagostomopsis) incisus and “Lagostomus (Lagostomopsis) spicatus”, have been recorded from the Monte Hermoso Formation (Montehermosan–Lower Chapadmalalan, Early Pliocene) of southern Buenos Aires Province, eastern Argentina. L. (L.) incisus is based on skull remains,while “L. (L.) spicatus” is based onmandible remains and fragmentary skulls. Detailed study of specimens recovered from the upper section of the Monte Hermoso Formation, from the Irene “Formation”, and the Chapadmalal Formation (late Early–early Late Pliocene, Buenos Aires Province), some of them represented by associated skull and mandible remains, indicates that L. (L.) incisus and “L. (L.) spicatus” are synonymous, with the valid name being L. (L.) incisus. The differences between both nominal species are here attributed to different ontogenetic states and sexual dimorphism. The stratigraphic provenance of the fossil material of L. (L.) incisus indicates a temporal distribution of this species restricted to theMontehermosan?–Chapadmalalan (Early–early Late Pliocene), instead of the Montehermosan (Early Pliocene).
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First record of a basal neoceratopsian dinosaur from the Late Cretaceous of Kazakhstan
Autorzy:
Averianov, A
Sues, H.D.
Powiązania:
https://bibliotekanauki.pl/articles/23104.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
first record
neoceratopsian dinosaur
dinosaur
Late Cretaceous
Cretaceous
Kazakhstan
systematics
Aral Sea
Opis:
The oldest known ceratopsians come from the Late Jurassic of China (Zhao et al. 1999; Xu et al. 2006). During the Early Cretaceous, the basal ceratopsian Psittacosaurus was among the most common dinosaurs in Asia but more derived basal neoceratopsians were quite rare on that continent (Xu et al. 2002; Makovicky and Norell 2006). Basal neoceratopsians became more abundant in the Late Cretaceous of Mongolia and China, although they are not known in this region from the latest Cretaceous (You and Dodson 2004; Alifanov 2008). In contrast, basal neoceratopsians are rare during the Early Cretaceous in North America but became common and diverse during the Campanian and Maastrichtian (You and Dodson 2004; Chinnery and Horner 2007). Little is known about the evolutionary history of this group in more inland regions of what are now Kazakhstan and adjoining countries. Asiaceratops documents the presence of basal neoceratopsians in the Cenomanian of Uzbekistan (Nessov et al. 1989). Here we report on the first record of a basal neoceratopsian in the Late Cretaceous of Kazakhstan, based on two cranial bones from the Turonian Zhirkindek Formation in the northeastern Aral Sea region.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 3; 553-556
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New psittacosaurid highlights skull enlargement in horned dinosaurs
Autorzy:
Sereno, P C
Xijin, Z.
Brown, L.
Lin, T.
Powiązania:
https://bibliotekanauki.pl/articles/23127.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Psittacosaurus
systematics
Cretaceous
Dinosauria
China
Marginocephalia
dinosaur
skull length
Yixian Formation
paleontology
Ornithischia
Opis:
A new psittacosaurid is based on a nearly complete articulated skeleton from northeastern China that differs principally in skull size as compared to the most common and widespread species, Psittacosaurus mongoliensis. The skull of Psittacosaurus majorsp. nov., is 25% larger despite very similar postcranial skeletal dimensions. Such selective skull enlargement is very unusual. Skull size in ceratopsians, in general, scales with positive allometry relative to body mass: species of greater mass have proportionately larger skulls. This pattern stands in marked contrast to that for other vertebrate herbivores, in which larger−bodied species either have proportionately similar or smaller skulls relative to body mass. Larger−bodied ceratopsians evolved skulls that are 50% or more of trunk length—as measured without their expansive cranial frill. Although contemporaneous duck−billed dinosaurs also exhibit some positive allometry in the skull, skull length remains approximately 35% of trunk length. The evolution of extraordinary absolute and relative skull size among ceratopsians appears to have been driven by sexual selection and involved the tandem evolution of reduced head mobility and an obligate quadrupedal posture.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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