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Upper Miocene (upper + miocene)
Selected AbstractsA NEW AMPHICYONINE (CARNIVORA: AMPHICYONIDAE) FROM THE UPPER MIOCENE OF BATALLONES-1, MADRID, SPAINPALAEONTOLOGY, Issue 4 2008STÉPHANE PEIGNÉ Abstract:, The vertebrate community of the late Miocene locality of Batallones-1, Madrid Province, Spain, is mainly composed of mammals of the order Carnivora, which represents 98 per cent of the total number of macro-mammal fossils. Here, we describe craniodental remains of approximately 12 individuals of a new, highly specialized member of the Amphicyonidae, previously assigned to Amphicyon sp. cf. A. castellanus. A phylogenetic analysis of Amphicyoninae shows that this new form, named Magericyon anceps gen. et sp. nov., is markedly distinct from all other known Amphicyoninae, specifically in its hypercarnivorous features (strongly compressed upper canines, absence of dP1/dp1 and P2/p2, single-rooted p3, absence of a metaconid on the lower molars, and reduction of M2 relative to M1). [source] Piceoxylon pseudotsugae GOTHAN emend.FEDDES REPERTORIUM, Issue 1 2001Deutschland, VAN DER BURGH aus dem Obermiozän von Ottendorf-Okrilla bei Dresden 1987 konnte im Westteil der Kiesgrube Ottendorf-Okrilla (höheres Obermiozän) aus Tonen mit kohligen Schmitzen ein 1,14 m langer Stammrest geborgen werden. Er wird als Piceoxylon pseudotsugae Gothan 1906 emend, van der Burgh (1973) bestimmt. Das fossile Holz zeigt große Ähnlichkeit mit der heute noch im pazifischen Nordamerika beheimateten Pseudotsuga menziesii (Mirb.) Franco. Xylotomische Nachweise dieser Art sind bis heute nur wenige bekannt. Sie stammen aus Nordamerika, Deutschland (Rheinland), Österreich und Slask (Schlesien/Polen). Zu der anatomischen Beschreibung des Holzes wird die Ökologie der rezenten und die Paläookologie der fossilen Pseudotsuga diskutiert. Piceoxylon pseudotsugae Gothan emend. Van der Burgh from the Upper Miocene from Ottendorf-Okrilla near Dresden, Germany. A fossil wood, collected in Ottendorf-Okrilla by H. Kubasch, Kamenz, is described in this paper. It is identified by the first author as Piceoxylon pseudotsugae Gothan 1906 emend, van der Burgh 1973 because of its clear spiral thickenings in the tracheids (early and late wood) together with vertical and horizontal resin ducts. Tertiary wood assigned to this species is up till now only known from a few localities in North America and Europe (Rheinland/Germany, Austria, Silesia/Poland). The recent comparable species, Pseudotsuga menziesii (Mirb.) Franco, is known from a wide variety of localities in North America, with a very variable range concerning temperature. It is a tree of well drained, slightly acidic soils, preferably on sedimentary rocks with a volcanic or glacial origin. In the Tertiary of Europe this tree is also known from brown coal deposits. Therefore, for the Tertiary species a habitat in swamp environment must be added. [source] Exceptionally preserved tadpoles from the Miocene of Libros, Spain: ecomorphological reconstruction and the impact of ontogeny upon taphonomyLETHAIA, Issue 3 2010MARIA E. MCNAMARA McNamara, M.E., Orr, P.J., Kearns, S.L., Alcalá, L., Anadón, P. & Peñalver-Mollá, E. 2010: Exceptionally preserved tadpoles from the Miocene of Libros, Spain: ecomorphological reconstruction and the impact of ontogeny upon taphonomy. Lethaia, Vol. 43, pp. 290,306. The Libros exceptional biota from the Upper Miocene of NE Spain includes abundant frog tadpoles (Rana pueyoi) preserved in finely laminated lacustrine mudstones. The tadpoles exhibit a depressed body, short tail, low tail fins, dorso-laterally directed eyes and jaw sheaths; these features identify the Libros tadpoles as members of the benthic lentic ecomorphological guild. This, the first ecomorphological reconstruction of a fossil tadpole, supports phylogenetic evidence that this ecology is a conserved ranid feature. The soft-tissue features of the Libros tadpoles are characterized by several modes of preservation. The space occupied previously by the brain is defined by calcium carbonate, the nerve cord is defined by calcium phosphate, and jaw sheaths and bone marrow are preserved as organic remains. Gut contents (and coprolites adjacent to specimens) comprise ingested fine-grained sedimentary detritus and epiphyton. The body outline and the eyespots, nares, abdominal cavity, notochord, caudal myotomes and fins are defined by a carbonaceous bacterial biofilm. A similar biofilm in adult specimens of R. pueyoi from Libros defines only the body outline, not any internal anatomical features. In the adult frogs, but not in the tadpoles, calcium phosphate and calcium sulphate precipitated in association with integumentary tissues. These differences in the mode of preservation between the adult frogs and tadpoles reflect ontogenetic factors. ,Anuran, ecology, soft-tissue, tadpoles, taphonomy. [source] Rock magnetism and paleomagnetic stratigraphy of forearc sediments of the Japan Trench, ODP Sites 1150 and 1151ISLAND ARC, Issue 1 2004Toshiya Kanamatsu Abstract Magnetic measurements were carried out to investigate rock magnetic properties and paleomagnetic directions of late and middle Miocene sediments recovered from the land side of the Japan Trench during the Ocean Drilling Program Leg 186. Because the low coercive component in natural remanent magnetization (NRM) normalized by anhysteretic remanent magnetization shows that the drilling-induced magnetization is severe in the sections obtained by the advanced hydraulic piston coring method, careful analyses of demagnetization of NRM using the ,demagnetization plane' were carried out to decompose the direction and intensity. Magnetostratigraphic correlation down to the upper Miocene, supplemented by biostratigraphic data, revealed that the sedimentation rates are characterized by drastic changes, with the early Pliocene having the highest rate. This high sedimentation rate is related to the subsidence of the southern deep-sea terrace of the Japan Trench. [source] Phylogenetic relationships of the newly described species Chondrostoma olisiponensis (Teleostei: Cyprinidae)JOURNAL OF FISH BIOLOGY, Issue 4 2010H. F. Gante Phylogenies were generated using mitochondrial cytochrome b and nuclear ß-actin gene DNA sequences to infer the phylogenetic relationships of the newly described Chondrostoma olisiponensis. Results indicate that the species is monophyletic with species of the lemmingii -group in mtDNA phylogenies, while it is monophyletic with species of the arcasii -group in the nuclear ß-actin trees. This is in agreement with the morphological resemblance of C. olisiponensis to both species groups. Results from nuclear but not mitochondrial DNA indicate that one population could be currently hybridizing with sympatric Chondrostoma lusitanicum. Based on a relaxed clock calibration of cytochrome b, it is estimated that C. olisiponensis split 12·5,7·9 million years ago (middle,upper Miocene) from its most recent ancestor, which coincides with a period of endorrheism in the Iberian Peninsula. [source] A NEW SPECIES OF DICERORHINUS (RHINOCEROTIDAE) FROM THE PLIO-PLEISTOCENE OF MYANMARPALAEONTOLOGY, Issue 6 2008ZIN-MAUNG-MAUNG-THEIN Abstract:, A skull and mandible of the new species Dicerorhinus gwebinensis sp. nov. of Rhinocerotidae (Mammalia, Perissodactyla) is described. The material is collected from the upper part of the Irrawaddy sediments (Plio-Pleistocene) in central Myanmar. D. gwebinensis sp. nov. is morphologically more similar to the extant species D. sumatrensis (Sumatran rhinoceros) than to other species of the genus but differs from D. sumatrensis in having the comparatively shorter nasal, the more concave dorsal profile of the skull, the more elevated occiput and presence of molar crista in M3/. This is the first discovery of Dicerorhinus in the upper Miocene to lower Pleistocene of the Indian subcontinent and Mainland Southeast Asia, and fills the chronological and geographical gap of this lineage in Asia. The Dicerorhinus clade probably migrated into Southeast Asia from East Asia by the Pliocene or early Pleistocene. This hypothesis is supported by the scarcity or absence of this clade in the Neogene mammalian fauna of the Indian Subcontinent. [source] Depositional and tectonic evolution of a supradetachment basin: 40Ar/39Ar geochronology of the Nova Formation, Panamint Range, CaliforniaBASIN RESEARCH, Issue 1 2000N. P. Snyder The Nova Basin contains an upper Miocene to Pliocene supradetachment sedimentary succession that records the unroofing of the Panamint metamorphic core complex, west of Death Valley, California. Basin stratigraphy reflects the evolution of sedimentation processes from landslide emplacement during basin initiation to the development of alluvial fans composed of reworked, uplifted sections of the basin fill. 40Ar/39Ar geochronology of volcanic units in middle and lower parts of the sequence provide age control on the tectonic and depositional evolution of the basin and, more generally, insights regarding the rate of change of depositional environments in supradetachment basins. Our work, along with earlier research, indicate basin deposition from 11.38 Ma to 3.35 Ma. The data imply sedimentation rates, uncorrected for compaction, of ~100 m Myr,1 in the lower, high-energy part to ~1000 m Myr,1 in the middle part characterized by debris-flow fan deposition. The observed variation in sediment flux rate during basin evolution suggests that supradetachment basins have complex depositional histories involving rapid transitions in both the style and rate of sedimentation. [source] | ||||||||||||||||||||||