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Wyszukujesz frazę "mammal diversity" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Climate and changes in mammal diversity during the late Pleistocene-Holocene in the Pampean Region [Argentina]
Autorzy:
Prado, J L
Alberdi, M T
Azanza, B
Sanchez, B
Powiązania:
https://bibliotekanauki.pl/articles/20763.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Argentina
Holocene
mammal diversity
mammal
diversity
change
extinction
Pleistocene
climate
paleontology
climate change
Opis:
The association of changes in mammal diversity with periods of global climatic change is suggestive of a causal relationship. Two important features in the testing of this climatic model are as follows: the timing and the pattern of the diversity changes, and the particular climatic variables examined, since different patterns of evolutionary interactions would be expected depending on different climatic variables. In order to analyse the relationship between climate change and faunal events, we need to establish a set of comparable data. To provide a finely resolved picture of both climatic and faunal events, the last 32,500-years were divided into 13 chronological units of 2,500-years each. The limit of 32,500-years was imposed by the availability of good localities with radioisotopic calibration. Climatic stability was measured in these analyses in terms of cycles per unit of time, the amount of variation in temperature per unit of time, and the magnitude of change between modal temperature of one interval less modal temperature from preceding interval. The data presented here suggest that the primary effect of climatic change is on: (1) levels of extinction (or migration) of large mammals; and (2) diversity and origination (or immigration) of small mammals.
Źródło:
Acta Palaeontologica Polonica; 2001, 46, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diversity and evolution of Hunter-Schreger Band configuration in tooth enamel of perissodactyl mammals
Autorzy:
Koenigswald, W.
Holbrook, L.
Rose, K.
Powiązania:
https://bibliotekanauki.pl/articles/23264.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Mammalia
Perissodactyla
tooth enamel microstructure
functional adaptation
phylogenesis
diversity
evolution
mammal
perissodactyl mammal
tooth
fossil
Hunter-Schreger Band
Opis:
Four different Hunter−Schreger Band (HSB) configurations were observed in the teeth of fossil and extant Perissodactyla. This variability exceeds that observed in Artiodactyla or Proboscidea. The four HSB configurations represent two different evolutionary pathways. Transverse HSB found in many mammalian taxa outside the Perissodactyla represents the most primitive HSB configuration. It occurs in several primitive perissodactyl families and is retained in Palaeotheriidae and extant Equidae. Curved HSB evolved from transverse HSB and occurs in Tapiridae, Helaletidae, and Lophiodontidae, as well as in Ancylopoda and Titanotheriomorpha. This likely indicates independent evolution of curved HSB in two or more lineages, but the number of instances of parallelism of this configuration is obscured by uncertainty in the relationships among these taxa and by a lack of data for some important basal taxa. A second evolutionary pathway leads from transverse HSB via compound HSB to vertical HSB. Compound HSB were detected in Hyrachyidae, Deperetellidae, and the early rhinocerotid Uintaceras. Vertical HSB configuration characterizes the molar dentition of other Rhinocerotidae, Hyracodontidae, Indricotheriidae, and Amynodontidae. Often, the incisors of rhinocerotids retain traces of compound HSB. Thus the HSB configuration reflects phylogenetic relationships to some degree. The selective value of the modified HSB configurations is interpreted functionally as a mechanism to reduce abrasion during mastication, assuming that the perpendicular intersection of prisms with the actual grinding surfaces resists wear better than prisms running parallel to the occlusal surface.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diversity of the adapisoriculid mammals from the early Palaeocene of Hainin, Belgium
Autorzy:
De Bast, E.
Sige, B.
Smith, T.
Powiązania:
https://bibliotekanauki.pl/articles/23133.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
diversity
adapisoriculid mammal
Early Paleocene
Paleocene
Hainin
Belgium
Mammalia
Adapisoriculidae
phylogenesis
paleontology
Opis:
Adapisoriculidae are an enigmatic group of small mammals known from the late Cretaceous of India, and from the early Palaeocene to early Eocene of Europe and Africa. Based on their primitive dental morphology, they have been classified as didelphids, nyctitheriids, leptictids, mixodectids, tupaiids, and palaeoryctids. While the latest hypothesis based on dental morphology suggests an affinity with Lipotyphla, postcranial remains indicate a close relationship with Euarchonta. Here, we present new adapisoriculid dental remains from the early Palaeocene locality of Hainin (Belgium). Adapisoriculidae are particularly abundant in Hainin, where they represent about one third of the mammalian fauna, offering new insights into both their specific and generic phylogenetic interrelationships. We describe three new species (Afrodon gheerbranti sp. nov., Bustylus folieae sp. nov. and Proremiculus lagnauxi gen. et sp. nov.) and document the previously unknown lower dentition of Bustylus marandati. The diversity of dental morphologies observed in the Hainin fauna suggests different interrelationships than previously suggested. In particular, the genus Proremiculus is considered morphologically intermediate between Afrodon and Remiculus, and the latter is no longer recognised as the sister group of Adapisoriculus. Although the highest diversity of adapisoriculids occurs in Europe, the oldest and most primitive members of the family were found in India and Africa, respectively. The geographic origin of the family could thus be located in any of these three continents, depending on the importance attributed to each of these factors. The coexistence of primitive and derived adapisoriculids at Hainin might indicate a very quick diversification in Europe, probably starting around the K−T boundary.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphological disparity in Plio-Pleistocene large carnivore guilds from Italian Peninsula
Autorzy:
Meloro, C.
Powiązania:
https://bibliotekanauki.pl/articles/22061.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Carnivora
Italian Peninsula
Italy
morphological diversity
Pleistocene
Plio-Pleistocene
Quaternary
geometrical morphometry
large mammal
mandible shape
paleontology
morphological variability
taxonomy
Opis:
Communities of large mammals exhibit changes in morphological diversity through space and time; changes that are possibly correlated to distinct aspects of the physical environment. Here, I explore shape changes in the trophic apparatus of large carnivore guilds, comparing extant communities with Quaternary ones, from peninsular Italy. Mandibular shape is quantified through geometric morphometrics and its disparity is computed for each carnivore guild. Patterns of morphospace occupation through space and time reveal that extant carnivore guilds are negatively influenced by number of artiodactyls. Very productive ecosystems show low values of morphological disparity because species tend to occupy central regions of the morphospace rather than extreme areas. Disparity of mandibular corpus shape remains relatively stable throughout the Quaternary in the large carnivore communities of the Italian peninsula. They exhibit similar values to extant guilds because the trophic apparatus did not evolved important morphological novelties. Interestingly, carnivore guilds of the late Pliocene (3.5 Ma) and early Pleistocene (0.8 Ma) show over−dispersed or random morphospace occupation because of a depleted fauna, precluding successive structural changes. The same applies for the extant European carnivore guild as a result of recent extinctions without replacement.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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