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Tytuł:
A morganucodontan mammalia form from the Upper Jurassic Morrison Formation, Utah, USA
Autorzy:
Davis, Brian M.
Jäger, Kai R.K.
Rougier, Guillermo W.
Trujillo, Kelli
Chamberlain, Kevin
Powiązania:
https://bibliotekanauki.pl/articles/2216314.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Mammalia
Morganucodonta
dentition
Jurassic
Morrison Formation
Opis:
We describe two skull fragments of a new morganucodontan from the Cisco Mammal Quarry (Upper Jurassic Morrison Formation), preserving portions of the palate and snout in excellent 3D detail as well as the complete upper postcanine dentition. Morganucodontans are best known by isolated elements and relatively complete skulls of several species of Morganucodon from the Lower Jurassic of Wales and China; this group is fundamental to our understanding of the early evolution of mammals. Cifellilestes ciscoensis gen. et sp. nov. possesses derived features of the snout paired with plesiomorphic construction of the molars; the distal premolars are complex and there is an unusually low count (two) of strongly imbricated molars. This character combination expands craniodental variation for the group. We sampled mudstone from the Cisco Mammal Quarry for ash-fall zircon analysis and obtained a date of 151.50 ± 0.28 Ma. This dates the locality to the earliest Tithonian and slightly younger than other major dated mammalbearing localities in the Morrison Formation. Cifellilestes represents one of the youngest members of this group and extends the record of morganucodontans in North America by more than 30 Ma. Morganucodontans are a rare component of Late Jurassic faunas but display surprising dental diversity through variations in a tooth count and cusp morphology of a deeply conserved, generalized mammalian tooth pattern, which was fully established in brasilodontid (non-mammalian) ancestors at least 80 my prior.
Źródło:
Acta Palaeontologica Polonica; 2022, 67, 1; 77-93
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dentition and relationships of the Jurassic mammal Shuotherium
Autorzy:
Kielan-Jaworowska, Z
Cifelli, R.L.
Luo, Z.
Powiązania:
https://bibliotekanauki.pl/articles/23028.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
molar
mammal
dentition
China
Shuotherium
Australosphenida
Jurassic
paleontology
Opis:
The Middle Jurassic mammal Shuotherium has lower molars that possess a trigonid and talonid, but are unique in having the talonid situated in front of the trigonid, rather than behind it, as in molars of usual tribosphenic pattern. Shuotherium dongi Chow and Rich, 1982 was based on a dentary bearing seven teeth, originally interpreted as three premolars and four molars. Based on comparison with other groups of early mammals, we reinterpret the premolar–molar boundary in the holotype of S. dongi, and propose a dental formula of four (or more) premolars and three molars. The ultimate lower premolar (previously identified as the first molar) has a completely developed trigonid and no talonid or pseudo−talonid. We hypothesize that the mesial cingulid on molars of Australosphenida is a highly plausible structural antecedent to the pseudo−talonid of Shuotherium. This and other shared, derived features support a relationship of Shuotherium and Australosphenida as sister−taxa. We hypothesize that the common ancestor of Shuotherium + Australosphenida had a global distribution no younger than early Middle Jurassic, and that the respective clades diverged prior to full separation of Gondwanan and Laurasian landmasses.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyperdontia: Exploring the developmental abnormality
Autorzy:
Arandi, N.Z.
Powiązania:
https://bibliotekanauki.pl/articles/2098201.pdf
Data publikacji:
2020
Wydawca:
Instytut Medycyny Wsi
Tematy:
hyperdontia
dental abnormality
supernumerary tooth
dentition
developmental abnormality
Opis:
Introduction and objective. Hyperdontia is a dental developmental anomaly in which supernumerary teeth exist. These are extra teeth to the normal set of primary or permanent dentitions. This article reviews the current literature on hyperdontia in the permanent dentition. Materials and method. A thorough literature search was carried out using Scopus, PubMed, and Google Scholar databases. Results were reviewed, prioritized, and findings compiled. The key words of the search strategy were: prevalence, case reports, supernumerary, supplemental, distomolars, forth molars, paramolars, parapremolars, mesiodens, and supernumerary lateral incisors. Only articles in English published in peer-reviewed journals were included. Brief description of the state of knowledge. The prevalence of supernumerary teeth varies between and within different populations. They may cause various aesthetic, occlusal, and functional complications and often require an interdisciplinary intervention. Familiarity with such anomalies is essential for the dental practitioner. Recognition and correct identification of the anomaly is important when communicating with other dental team members, especially in the case of a referral to or from another dental office. Moreover, understanding the anomaly is an important factor in determining the course of treatment, if any. Conclusion. It is hoped that this review will provide dental practitioners with an update on the classification, characteristics, and prevalence figures for each type of supernumerary tooth.
Źródło:
Journal of Pre-Clinical and Clinical Research; 2020, 14, 4; 178-183
1898-2395
Pojawia się w:
Journal of Pre-Clinical and Clinical Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Highly derived eutherian mammals from the earliest Cretaceous of southern Britain
Autorzy:
SWEETMAN, STEVEN C.
SMITH, GRANT
MARTILL, DAVID M.
Powiązania:
https://bibliotekanauki.pl/articles/945956.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
mammalia
eutheria
dentition
early cretaceous
purbeck group
britain
uk
Opis:
Eutherian mammals (Placentalia and all mammals phylogenetically closer to placentals than to marsupials) comprise the vast majority of extant Mammalia. Among these there is a phenomenal range of forms and sizes, but the origins of crown group placentals are obscure. They lie within the generally tiny mammals of the Mesozoic, represented for the most part by isolated teeth and jaws, and there is strongly conflicting evidence from phenomic and molecular data as to the date of origin of both Eutheria and Placentalia. The oldest purported eutherians are Juramaia from the Upper Jurassic of China, and Eomaia and Acristatherium from the Lower Cretaceous, also of China. Based on dental characters and analyses of other morphological and molecular data, doubt has recently been cast on the eutherian affinities of the Chinese taxa and consequently on the date of emergence of Eutheria. Until now, the only tribosphenic mammal recorded from the earliest Cretaceous (Berriasian) Purbeck Group of Britain was the stem tribosphenidan Tribactonodon. Here we document two new tribosphenic mammals from the Purbeck Group, Durlstotherium gen. nov. and Durlstodon gen. nov., showing highly derived eutherian molar characters that support the early emergence of this clade, prior to the Cretaceous.
Źródło:
Acta Palaeontologica Polonica; 2017, 62, 4; 657-665
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Early Devonian ischnacanthiform acanthodian Ischnacanthus gracilis (Egerton, 1861) from the Midland Valley of Scotland
Autorzy:
Burrow, C. J.
Newman, M.
den Blaauwen, J.
Jones, R.
Davidson, R.
Powiązania:
https://bibliotekanauki.pl/articles/139010.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Acanthodii
Ischnacanthus
Lochkovian
palaeohistology
dentition
fałdopłetwe
akantody
lochkov
dewon wczesny
paleohistologia
uzębienie
Opis:
Ischnacanthus gracilis (Egerton, 1861), the only ischnacanthiform acanthodian from the Lochkovian Lower Old Red Sandstone of Scotland, is known from hundreds of specimens in institutional collections worldwide. Despite this relative abundance, morphology and histology of its skeletal elements have rarely been investigated. Surface details of spines, dental elements, and scales are often not visible in specimens because they are usually split through the middle. We have examined a broad size range of fish, from 35 mm to 250 mm long. Several intact (not split) specimens have been collected in recent years and acid-prepared to show fine details of the dermal and dental elements. We have also used scanning electron microscopy of scales, jaws and dental elements, denticles and fin spines, and serial thin sectioning of articulated specimens, to document their structure. Some of our notable observations include: identification of ventral lateral lines, double-layered subtessellate calcified cartilage forming the jaws, and the probable occurrence of extraoral tricuspid denticles on the jaws of most fish. Examination of the size range, body proportions and dentition of institutional specimens gives no support for recognising more than one species in the Midland Valley localities.
Źródło:
Acta Geologica Polonica; 2018, 68, 3; 335-362
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The heterodonty in euselachian sharks from the Pennsylvanian of Nebraska
Autorzy:
Ginter, M.
Powiązania:
https://bibliotekanauki.pl/articles/138726.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Euselachii
dentition
Carboniferous
Indian Cave Sandstone
USA Midcontinent
uzębienie
karbon
jaskinia piaskowa
USA
Opis:
Among the rich material of chondrichthyan microremains from the Indian Cave Sandstone (Upper Pennsylvanian, Gzhelian) near Peru, Nebraska, USA, housed at the Carnegie Museum of Natural History, there occur almost sixty teeth representing Euselachii. They belong to at least seven species, presenting various types of heterodonty. Two new species are described, viz. Ossianodus nebraskensis gen. et sp. nov., whose dentition is similar to that of certain Mesozoic hybodonts, and Sphenacanthus tenuis sp. nov. with minute teeth of protacrodont design. Most of the euselachian teeth served to crush or grind prey, and some had the potential to clutch, but cutting teeth are absent from the fauna.
Źródło:
Acta Geologica Polonica; 2016, 66, 3; 299-312
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New features of the snout and orbit of a therocephalian therapsid from South Africa
Autorzy:
Sigurdsen, T
Powiązania:
https://bibliotekanauki.pl/articles/21325.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Akidnognathidae
dentition
Karoo basin
Therocephalia
therocephalian therapsid
South Africa
tooth
Therapsida
Synapsida
paleontology
Opis:
I describe the anterior part of the externally poorly preserved skull of a therocephalian from the Karoo Basin in South Africa, using the method of serial grinding. The skull is incomplete, and its estimated length in life is 130 mm. The skull can be assigned to the Akidnognathidae with some confidence. The stratigraphic age of the specimen and its locality are not known, but the surrounding sediment suggests that it may be from the Upper Permian Dicynodon Assemblage Zone. It has five or six postcanine teeth, and a poorly developed crista choanalis. The sinuses and canals of the snout are recognized, and it is believed that the sinus positioned posteriorly in the snout (posterior maxillary sinus) is homologous with the maxillary sinus of anomodonts and cynodonts. It also shows similarities to the infraorbital canal of early mammals, such as Morganucodon. An anteriorly positioned sinus (anterior maxillary sinus), situated directly behind the canine root, is homologized with the maxillary sinus of gorgonopsians. In addition, I identify the previously undescribed canal (designated anterior maxillary canal), leading from the anterior maxillary sinus antero−dorsally. No evidence for maxilloturbinals was found in contrast to the condition known in the primitive therocephalian Glanosuchus
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New data on the dentition of the scincomorphan lizard Polyglyphanodon sternbergi
Autorzy:
Nydam, R L
Cifelli, R.L.
Powiązania:
https://bibliotekanauki.pl/articles/22344.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Polyglyphanodontinae
dentition
Polyglyphanodon sternbergi
Late Cretaceous
scincomorphan lizard
Squamata
lizard
North America
paleontology
Opis:
Polyglyphanodon sternbergi Gilmore, 1940 is a large−bodied lizard from the Late Cretaceous of North America distinguished by its transversely oriented, interlocking teeth. Initially the teeth of P. sternbergi were described as smooth and blade−like, but recent discoveries of new specimens from the type locality and re−examination of the original material indicate that the chisel−like teeth of P. sternbergi have small, irregular serrations along the blades. These serrations are similar in size to those found on the teeth of the modern herbivorous lizard Iguana iguana and were likely used in a similar manner to crop vegetation, but was also capable of a degree of oral food processing due to the transverse orientation and interlocking arrangement of the dentition of P. sternbergi. Additionally, the presence of transversely oriented teeth with V−shaped blades in the anterior portion of the tooth row of P. sternbergi represents an additional shared characteristic in tooth structure between P. sternbergi and Dicothodon moorensis, Bicuspidon numerosus, and Peneteius aquilonoius; all transversely−tooth polyglyphandontine lizards from the Cretaceous of North America. It appears that the unique dentitions of Polyglyphanodon sternbergi (large teeth with transverse, serrated blades) and Peneteius aquilonius (small teeth with mammal−like specializations) present by the end of the Cretaceous were derived from a bicuspid, transversely oriented precursor tooth with a V−shaped blade.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mandibular dentition in the Late Triassic temnospondyl amphibian Metoposaurus
Autorzy:
Konietzko-Meier, D
Wawro, K.
Powiązania:
https://bibliotekanauki.pl/articles/20771.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Silesian region
Late Triassic
Metoposaurus diagnosticus krasiejowensis
mandibular dentition
Triassic
Polska
temnospondyl amphibian
paleontology
Opis:
The Temnospondyli are a large and diverse group of stemtetrapods (sensu Laurin and Reisz 1997) known from the Early Carboniferous to the Early Cretaceous; their remains have been found on all continents, from Greenland to Antarctica. The Metoposauridae are a short−ranging temnospondyl group recorded only from the Late Triassic; they are characterized by an anterior position of the orbits, a broad parasphenoid and a large quadrate foramen. However, unclear is the taxonomic value of the external location of tusks on the dentary. Our analysis of tooth rows in Metoposaurus diagnosticus krasiejowensis from the Triassic (Late Carnian) of Krasiejów (Silesia, SW Poland) shows that the external location of tusks on the dentary is not a synapomorphy for Metoposauridae but a character of great intraspecific variability. Variability of the arrangement of the internal tooth row on the upper jaw has also been observed.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kielantherium, a basal tribosphenic mammal from the Early Cretaceous of Mongolia, with new data on the aegialodontian dentition
Autorzy:
Lopatin, A
Averianov, A.
Powiązania:
https://bibliotekanauki.pl/articles/23180.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Kielantherium gobiense
Early Cretaceous
mammal
dentition
Cretaceous
Mammalia
Mongolia
Aegialodontia
Tribosphenida
tribosphenic mammal
paleontology
Opis:
Two additional specimens of the basal tribosphenid mammal Kielantherium gobiense, the first known aegialodont upper molar (possibly M2) and a dentary fragment with m1, are described from the Early Cretaceous Höövör locality in Mongolia. The upper molar shows an initial stage of the protocone development. Kielantherium gobiense has been known from two specimens only, and thus the new material doubles the hypodigm of this species. Kielantherium is clearly not a junior synonym of Aegialodon, as it differs from the latter in having a cusp−like mesiolabial cingulid cuspule f rather than prominent ridge−like precingulid. Kielantherium's lower postcanine dental formula (with four or more premolars and four molars) is distinctive and more primitive than in Peramus and Eutheria which have five premolars and three molars, and Metatheria which have three premolars and four molars.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New teeth of allotherian mammals from the English Bathonian, including the earliest multituberculates
Autorzy:
Butler, P M
Hooker, J.J.
Powiązania:
https://bibliotekanauki.pl/articles/22031.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
English Bathonian
tooth cusp
mammal
tooth
Allotheria
Jurassic
Bathonian
multituberculate
Haramiyida
dentition
new tooth
paleontology
Multituberculata
Opis:
Twenty one isolated multituberculate−like teeth are described from the Forest Marble (late Bathonian) of Oxfordshire and Dorset, England. Eighteen are additional to the teeth described as Eleutherodon oxfordensis by Kermack et al. (1998), and three of those are placed in new taxa. Six new molars of Eleutherodon provide further information on variation in size, proportion and root pattern. Millsodon superstes gen. et sp. nov. (family indeterminate), based on first and last lower molars and a referred upper molar, has resemblances to Haramiyidae and Theroteinidae. Kirtlingtonia catenata gen. et sp. nov. (family indeterminate), based on last upper molars and a probable upper premolar, has a slight resemblance to Eleutherodon, and also to M2 of some paulchoffatiid multituberculates. Kermackodon multicuspis gen. et sp. nov. (family Kermackodontidae nov.) and Hahnotherium antiquum gen. et sp. nov. (family Hahnotheriidae nov.) are based on second upper molars, recognised as multituberculate by their horizontal wear and inferred occlusal displacement with respect to m2. A lower molar referred to H. antiquum confirms this. A blade−like lower premolar and an upper premolar with conical cusps, referred to Kermackodon, are multituberculate−like, but distinctive. Divergence between the two Bathonian multituberculates indicates that the order originated much earlier, more probably from a haramiyid than from a morganucodontid source. Mojo is regarded as probably a haramiyid. The Hahnodontidae, which have basined wear, are removed from the Multituberculata to the “Haramiyida”.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The teeth of the unenlagiine theropod Buitreraptor from the Cretaceous of Patagonia, Argentina, and the unusual dentition of the Gondwanan dromaeosaurids
Autorzy:
Gianechini, F.A.
Makovicky, P.J.
Apesteguia, S.
Powiązania:
https://bibliotekanauki.pl/articles/20408.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
tooth
unenlagiine theropod
theropod
Buitreraptor
Cretaceous
Patagonia
Argentina
dentition
Gondwanan dromaeosaurid
dromaeosaurid
Theropoda
Dromaeosauridae
Unenlagiinae
Dinosauria
paleontology
dinisaur tooth
Opis:
The Unenlagiinae is a clade of Gondwanan dromaeosaurid theropods mainly known from incomplete skeletal material. The group includes two recently discovered theropods, Buitreraptor and Austroraptor, from which cranial remains are available with in situ maxillary and dentary teeth, thus allowing the study of tooth morphology. Among the derived traits that diagnose the dentition of unenlagiines are: (i) high tooth count, (ii) small size of individual teeth when compared with skull height, (iii) absence of denticles and carinae, and (iv) presence of longitudinal grooves on the tooth crown. This suite of dental characteristics, shared between Buitreraptor and Austroraptor, can be considered as diagnostic of the Unenlagiinae or, at least, a more exclusive clade within the group. The teeth of Buitreraptor exhibit a remarkable labiolingual compression, whereas Austroraptor possesses more conical teeth, probably respective autapomorphic features. On one hand, these dental morphologies differ from those observed in most Laurasian dromaeosaurids and, for instance, could be considered as further proof of the purported vicariant evolution of the lineage on the southern continents. On the other hand, the morphological similarities (e.g., absence of denticles) between the teeth of unenlagiines and other theropod lineages, including Mesozoic birds and ornithomimosaurs, can be considered as the result of parallel trends related to dental reduction.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First Mesozoic record of the stingray Myliobatis wurnoensis from Mali and a phylogenetic analysis of Myliobatidae incorporating dental characters
Autorzy:
Claeson, K.M.
O'Leary, M.A.
Roberts, E.M.
Sissoko, F.
Bouare, M.
Tapanila, L.
Goodwin, D.
Gottfried, M.D.
Powiązania:
https://bibliotekanauki.pl/articles/20545.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
first record
Mesozoic
stingray
Myliobatis wurnoensis
Mali
phylogenetic analysis
Myliobatidae
dentition
Chondrichthyes
Myliobatiformes
batoid fish
fish
Cretaceous
Maastrichtian
Opis:
New specimens, including the first record of lower dental plates, of the extinct myliobatid Myliobatis wurnoensis were recovered from the Maastrichtian (Late Cretaceous) of the Iullemmeden Basin, Mali, and are the oldest record of the taxon. We evaluated the phylogenetic position of this taxon with reference to other myliobatids (extinct and extant) using osteology and dentition. Our results indicate that Myliobatinae and Myliobatis are each paraphyletic, and that Aetobatus and Rhinoptera are monophyletic. We also found that taxa known only from the Cretaceous, Brachyrhizodus and Igdabatis, are highly nested within Myliobatidae. The phylogenetic position of these taxa unambiguously extends the origin of Myliobatidae and most of its representative taxa into the Mesozoic.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertebral morphology, dentition, age, growth, and ecology of the large lamniform shark Cardabiodon ricki
Autorzy:
Newbrey, M.G.
Siversson, M.
Cook, T.D.
Fotheringham, A.M.
Sanchez, R.L.
Powiązania:
https://bibliotekanauki.pl/articles/21003.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
morphology
dentition
age
growth
ecology
large lamniform shark
Cardabiodon ricki
Cardabiodon venator
Chondrichthyes
Lamniformes
Archaeolamna
Squalicorax
Cretaceous
Cenomanian
Turonian
Australia
Opis:
Cardabiodon ricki and Cardabiodon venator were large lamniform sharks with a patchy but global distribution in the Cenomanian and Turonian. Their teeth are generally rare and skeletal elements are less common. The centra of Cardabiodon ricki can be distinguished from those of other lamniforms by their unique combination of characteristics: medium length, round articulating outline with a very thick corpus calcareum, a corpus calcareum with a laterally flat rim, robust radial lamellae, thick radial lamellae that occur in low density, concentric lamellae absent, small circular or subovate pores concentrated next to each corpus calcareum, and papillose circular ridges on the surface of the corpus calcareum. The large diameter and robustness of the centra of two examined specimens suggest that Cardabiodon was large, had a rigid vertebral column, and was a fast swimmer. The sectioned corpora calcarea show both individuals deposited 13 bands (assumed to represent annual increments) after the birth ring. The identification of the birth ring is supported in the holotype of Cardabiodon ricki as the back-calculated tooth size at age 0 is nearly equal to the size of the smallest known isolated tooth of this species. The birth ring size (5-6.6 mm radial distance [RD]) overlaps with that of Archaeolamna kopingensis (5.4 mm RD) and the range of variation of Cretoxyrhina mantelli (6-11.6 mm RD) from the Smoky Hill Chalk, Niobrara Formation. The revised, reconstructed lower jaw dentition of the holotype of Cardabiodon ricki contains four anterior and 12 lateroposterior files. Total body length is estimated at 5.5 m based on 746 mm lower jaw bite circumference reconstructed from associated teeth of the holotype.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First evidence of a neonate dentition in pareiasaurs from the Upper Permian of Russia
Autorzy:
Kordikova, E G
Khlyupin, A J
Powiązania:
https://bibliotekanauki.pl/articles/22530.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
locality
Ursulov Formation
Upper Permian
skull fragment
skeleton
adult specimen
neonate
Pareiasauridae
fossil record
Vyatka River
dentition
Russia
Deltavjatia vjatkensis
Opis:
Finds of juvenile parareptiles are rare in the fossil record. We describe partial upper dentition with large vacuities between bones belonging to a neonate pareiasaur (preserved skull fragment is 22.4 mm long). The specimen was collected within 5 m from a skeleton of an adult specimen of Deltavjatia vjatkensis (Hartmann-Weinberg, 1937) (Pareiasauridae) from red calcareous mudstones in the upper part of the Vanyushonkov Member of Ursulov Formation (Upper Permian, Upper Tatarian substage, Vishkil'skiy regional stage) of Kotel'nich locality, Vyatka River region, Russia. Referral to Deltavjatia vjatkensis is based on the presence of heterodont dentition: spatulate maxillary, triconodont vomerine and conical, palatine and pterygoid teeth located on well-developed palate ridges. This is the first positively identified record of the neonate pareiasaur dentition.
Źródło:
Acta Palaeontologica Polonica; 2001, 46, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 16

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