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Faunal Similarity (faunal + similarity)
Selected AbstractsA RE-EVALUATION OF SPHENACODONTID SYNAPSID MATERIAL FROM THE LOWER PERMIAN FISSURE FILLS NEAR RICHARDS SPUR, OKLAHOMAPALAEONTOLOGY, Issue 1 2009DAVID C. EVANS Abstract:, Early Permian terrestrial vertebrate faunal assemblages of Laurasia are dominated by large ophiacodontid, sphenacodontid, and edaphosaurid synapsids. This pattern contrasts with the fauna recovered from the Early Permian fissure fill deposits near Richards Spur, Oklahoma, where derived nontherapsid synapsids are rare. The fragmentary remains of Thrausmosaurus serratidens constitute the only published report of Sphenacodontidae from this locality. Here, we re-evaluate T. serratidens in light of new information on the faunal assemblage of this locality. We confirm that the type material of T. serratidens cannot be assigned to Sphenacodontidae and conclude that it pertains to an indeterminate varanopid. We also describe new material, including a partial maxilla, several isolated jaw fragments with teeth, an isolated precaniniform tooth and a posterior cervical vertebra that represents unequivocal sphenacodontid remains from the Richards Spur assemblage. This material is the first definitive record of a eupelycosaurian synapsid other than a varanopid from this important locality. Faunal similarities between Richards Spur and the Bromacker Quarry, Germany, may be reflective of upland terrestrial communities during the Early Permian. [source] Biodiversity and biogeography of the islands of the Kuril ArchipelagoJOURNAL OF BIOGEOGRAPHY, Issue 9 2003Theodore W. Pietsch Abstract Aim Based on seven consecutive seasons of biotic survey and inventory of the terrestrial and freshwater plants and animals of the 30 major islands of the Kuril Archipelago, a description of the biodiversity and an analysis of the biogeography of this previously little known part of the world are provided. Location The Kuril Archipelago, a natural laboratory for investigations into the origin, subsequent evolution, and long-term maintenance of insular populations, forms the eastern boundary of the Okhotsk Sea, extending 1200 km between Hokkaido, Japan, and the Kamchatka Peninsula of Russia. A chain of more than 56 islands, the system is only slightly smaller than the Hawaiian Islands, covering an area of 15,600 km2 and providing 2409 km of coastline. Methods Collections of whole specimens of plants and animals, as well as tissue samples for future molecular studies, were made by teams of scientists from Russia, Japan, and the USA, averaging 34 people for each of the seven annual summer expeditions (1994,2000). Floral and faunal similarities between islands were evaluated by using Sorensen's coefficient of similarity. The similarity matrix resulting from pair-wise calculations was then subjected to UPGMA cluster analysis. Results Despite the relatively small geographical area of all islands combined, the Kuril Island biota is characterized by unusually high taxonomic diversity, yet endemism is very low. An example of a non-relict biota, it originated from two primary sources: a southern source, the Asian mainland by way of Sakhalin and Hokkaido, and a northern source by way of Kamchatka. The contribution of the southern source biota to the species diversity of the Kurils was considerably greater than the northern one. Main conclusion The Bussol Strait, lying between Urup and Simushir in the central Kurils, is the most significant biogeographical boundary within the Archipelago. Of lesser importance are two transitional zones, the De Vries Strait or ,Miyabe Line', which passes between Iturup and Urup in the southern Kurils, and the fourth Kuril Strait, between Onekotan and Paramushir in the northern Kurils. [source] Small mammal (rodents and lagomorphs) European biogeography from the Late Oligocene to the mid PlioceneGLOBAL ECOLOGY, Issue 4 2007Olivier Maridet ABSTRACT Aim, To analyse the fossil species assemblages of rodents and lagomorphs from the European Neogene in order to assess what factors control small mammal biogeography at a deep-time evolutionary time-scale. Location, Western Europe: 626 fossil-bearing localities located within 31 regions and distributed among 18 successive biochronological units ranging from c. 27 Ma (million years ago; Late Oligocene) to c. 3 Ma (mid Pliocene). Methods, Taxonomically homogenized pooled regional assemblages are compared using the Raup and Crick index of faunal similarity; then, the inferred similarity matrices are visualized as neighbour-joining trees and by projecting the statistically significant interregional similarities and dissimilarities onto palaeogeographical maps. The inferred biogeographical patterns are analysed and discussed in the light of known palaeogeographical and palaeoclimatic events. Results, Successive time intervals with distinct biogeographical contexts are identified. Prior to c. 18 Ma (Late Oligocene and Early Miocene), a relative faunal homogeneity (high interregional connectivity) is observed all over Europe, a time when major geographical barriers and a weak climatic gradient are known. Then, from the beginning of the Middle Miocene onwards, the biogeography is marked by a significant decrease in interregional faunal affinities which matches a drastic global climatic degradation and leads, in the Late Miocene (c. 11 Ma), to a marked latitudinal pattern of small mammal distribution. In spite of a short rehomogenization around the Miocene/Pliocene boundary (6,4 Ma), the biogeography of small mammals in the mid Pliocene (c. 3 Ma) finally closely reflects the extant situation. Main conclusions, The resulting biogeographical evolutionary scheme indicates that the extant endemic situation has deep historical roots corresponding to global tectonic and climatic events acting as primary drivers of long-term changes. The correlation of biogeographical events with climatic changes emphasizes the prevalent role of the climate over geography in generating heterogeneous biogeographical patterns at the continental scale. [source] Mammals in South American drylands: faunal similarity and trophic structureGLOBAL ECOLOGY, Issue 2 2000Ricardo A. Ojeda Abstract We compared the fauna of small mammals (less than 500 g body weight) among five major South American drylands (Atacama, Altiplano, Monte, Patagonia and Caatinga) and found considerable heterogeneity and distinctiveness in species richness and composition between these biomes. From a total of 89 recorded species, 76 of them are restricted to only one of these drylands. The highland desert, or Altiplano, is the biome with the highest number of species. Despite the marked differences in the composition of the mammalian fauna, the trophic structure shows a rather consistent pattern: herbivores are the most important trophic group in all drylands. This consistency seems to be more the result of phylogenetic inertia than of similar ecological processes. Our results are compared with recent studies on desert small mammals across continents. [source] The importance of bare marine sedimentary habitats for maintaining high polychaete diversity and the implications for the design of marine protected areasAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 7 2009Christopher R. S. Barrio Froján Abstract 1.Bare intertidal sedimentary habitats have received relatively little attention compared with their neighbouring vegetated habitats. An ecological comparison of benthic faunal assemblages inhabiting tropical intertidal seagrass beds and bare sediments has been made to assess the faunal similarity between the two habitats in south-east Asia. 2.The poorly developed taxonomy of most invertebrate taxa in the region precluded the full identification of many faunal groups. Only the polychaetes , which accounted for 76% of all the macrofaunal organisms collected , were identified to the lowest possible taxonomic level, yielding 177 nominal species belonging to 35 families. Ecological analyses suggested that although each habitat had a distinct polychaete assemblage, there were few differences between habitats based on a range of calculated assemblage diversity metrics. 3.Further analyses were applied to the data to test the performance of three strategies for optimizing the selection of sites for inclusion in potential marine protected areas. Strategies were based either on the total number of species, the number of rare or endemic species, or on the level of species richness (used as a surrogate for community structure). 4.All three strategies consistently captured above average numbers of species at most levels of conservation intensity. The merits of each strategy are considered in turn. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||