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Abstract: Eight skulls of beaked whales (Cetacea, Odontoceti, Ziphiidae), in six cases associated with elements of the mandible, were collected from a limited area (about 1.5 km2) and roughly from the same stratigraphic horizon at Cerro Colorado, 35 km south‐south‐west of the city of Ica (Peru), where the late Middle Miocene basal strata of the Pisco Formation crop out. They represent the highest concentration reported of fossil Ziphiidae. These finely preserved Cerro Colorado fossils are described and assigned to a new species Messapicetus gregarius, together with another specimen collected from sediments of the same age at Cerro la Bruja (33 km south‐east to Cerro Colorado). Messapicetus gregarius shares with M. longirostris Bianucci, Landini and Varola, 1992 (Tortonian of Italy), an extremely elongated rostrum, but is clearly different from the Italian species in the more distinct maxillary tubercle and prominential notch, the more robust premaxillary crest, and the abrupt ventrolateral descent of the medial margin of the maxilla from the vertex. A parsimony analysis reveals that Messapicetus belongs to a basal clade, which includes other ziphiids with a dorsally closed mesorostral groove and prenarial basin. The high concentration of specimens belonging to the same species (some of them tentatively identified as adult males and females), combined with the presence of a calf, supports the hypothesis of site fidelity; these cetaceans might have lived in a limited region for a long period for both breeding and feeding. Besides the eight specimens of M. gregarius, strata at Cerro Colorado include many other cetacean remains (with several specimens of the pontoporiid Brachydelphis including a foetus), pinnipeds, turtles, fishes, and birds. 相似文献
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Soil respiration in a Mediterranean oak forest at different developmental stages after coppicing 总被引:4,自引:0,他引:4
VANESSA TEDESCHI ANA REY† GIOVANNI MANCA‡ RICCARDO VALENTINI‡ PAUL G. JARVIS§ MARCO BORGHETTI 《Global Change Biology》2006,12(1):110-121
To assess the variation of soil respiration at different forest stages we measured it in a coppiced oak (Quercus cerris L.) chronosequence in central Italy during two campaigns, spanning 2 successive years, in four stands at different stages of the rotation: 1 year (S1), 5 years (S5), 10 years (S10) and 17 years (S17) after coppicing. The contribution of the different components of soil respiration flux (aboveground litter, belowground decomposition soil organic matter and root respiration) was estimated by a paired comparison of manipulative experiments between the recently coppiced stand (S1) and mature stand (S17). Ninety percent of soil respiration values were between 1.7 and 7.8 μmol m?2 s?1, with an overall mean (±SD) of 4.0±2.7 μmol m?2 s?1. Spatial variation of soil respiration was high (CV=44.9%), with a mean range (i.e. patch size) of 4.8±2.7 m, as estimated from a semivariance analysis. In the absence of limitation by soil moisture, soil respiration was related to soil temperature with the exponential Q10 model (average Q10=2.25). During summer, soil moisture constrained soil respiration and masked its dependence on soil temperature. Soil respiration declined over the years after coppicing. Assuming a linear decline with stand age, we estimated a reduction of 24% over a 20‐year‐rotation cycle. The response of soil respiration to temperature also changed with age of the stands: the Q10 was estimated to decrease from 2.90 in S1 to 2.42 in S17, suggesting that different components or processes may be involved at different developmental stages. The contribution of heterotrophic respiration to total soil respiration flux was relatively larger in the young S1 stand than in the mature S17 stand. 相似文献
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Linkage Disequilibrium between the Spinocerebellar Ataxia 3/Machado-Joseph Disease Mutation and Two Intragenic Polymorphisms, One of Which, X359Y, Affects the Stop Codon 总被引:1,自引:0,他引:1 下载免费PDF全文
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TOMMASO VIVIANI LUCIA CONTE GIOVANNI CRISTOFOLINI MARIA SPERANZA 《Botanical journal of the Linnean Society. Linnean Society of London》1991,105(2):113-136
VIVIANI, T., CONTE, L., CRISTOFOLINI, G. & SPERANZA, M., 1991. Sero-systematic and taximetric studies on the Phaseoleae (Fabaceae) and related tribes. One hundred and fifty-two species of Phaseoleae, Desmodieae, Indigofereae, Millettieae, Sophoreae and Swartzieae were subjected to a taximetric study. The serological relationships were analysed using 37 antigenic systems and 12 antisera upon a representative sample from the six tribes. The comparative use of taximetric and serological data allowed the following conclusions to be drawn: (1) the tribe Phaseoleae is not a natural taxon; the primitive complex Diocleinae-Glycininae, the more derived Phaseolinae, and the Cajaninae deserve tribal rank; the position of the remaining subtribes requires further examination. (2) The Desmodieae are related to the Phaseoleae, whereas the Indigofereae have little relation to them. (3) The Baphia -group in the Sophoreae is possibly related to the Phaseoleae ancestors, while the other Sophoreae belong to different phyletic lines. (4) Swartzia is morphologically related to the Sophoreae, but does not belong to the same natural group. (5) Sophoreae, Millettieae and Phaseoleae are three heterogeneous aggregates representing stages of increasing specialization, rather than elements of a single phyletic line. 相似文献
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BERNARDO DOURADO RANIERI FLÁVIA FONSECA PEZZINI QUEILA SOUZA GARCIA ALAIN CHAUTEMS MARCEL GIOVANNI COSTA FRANÇA 《Austral ecology》2012,37(1):125-133
The germination requirements of sexually reproducing plants are regulated by environmental factors such as temperature. Those factors acting at the germination phase are part of the regeneration niche, which is fundamental in the processes that contribute to habitat suitability and geographic distribution. We tested the hypothesis that rarity is associated with regeneration niche in three species of plants in the family Gesneriaceae (tribe Sinningieae), Sinningia rupicola (Mart.) Wiehler, Paliavana sericiflora Benth and Sinningia allagophylla (Mart.) Wiehler, which vary in their distribution and habitat specificity but share a small zone of sympatry in rocky fields south of Belo Horizonte in Minas Gerais, Brazil. The regeneration niche was tested using a seed germination experiment under controlled light conditions at seven fixed temperatures (10–40°C at 5°C intervals). Each of the three species germinated differently at the various temperatures. The species with the smallest geographic range, S. rupicola, also had the most restricted germination: germination peaked at 15°C when relatively few seeds germinated (45%), and even fewer germinated at other temperatures. The regeneration niche was wider in P. sericiflora and wider still in S. allagophylla, with germination greater than 90% between 15–25°C and greater than 80% between 15–30°C, respectively. Our germination results provide qualified support for the hypothesis of correlation of the regeneration niche with geographic distribution of related plant taxa, with important conservation implications for rare and endangered species. 相似文献
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ALICE MOUTON ANDREA GRILL MAURIZIO SARA BORIS KRYŠTUFEK ETTORE RANDI GIOVANNI AMORI RIMVYDAS JUŠKAITIS GAETANO ALOISE ALESSIO MORTELLITI FABIANA PANCHETTI JOHAN MICHAUX 《Biological journal of the Linnean Society. Linnean Society of London》2012,105(3):648-664
This is the first mitochondrial phylogeography of the common dormouse, Muscardinus avellanarius (Linnaeus, 1758), a hibernating rodent strictly protected in Europe (Habitat Directive, annex IV; Bern Convention, annex III). The 84 individuals of M. avellanarius, sampled throughout the distributional range of the species, have been sequenced at the mitochondrial DNA gene (cytochrome b, 704 base pairs). The results revealed two highly divergent lineages, with an ancient separation around 7.7 Mya and a genetic divergence of 7.7%. Lineage 1 occurs in Western Europe (France, Belgium, and Switzerland) and Italy, and lineage 2 occurs in Central–Northern Europe (Poland, Germany, Latvia, and Lithuania), on the Balkan Peninsula, and in Turkey. Furthermore, these two lineages are subdivided into five sublineages genetically isolated with a strong geographical association. Therefore, lineage 1 branches into two further sublineages (Western European and Italian), whereas lineage 2 contained three sublineages (Central–Northern European, Turkish, and Balkan). We observed low genetic diversity within the sublineages, in contrast to the significant level of genetic differentiation between them. The understanding of genetic population structure is essential for identifying units to be conserved. Therefore, these results may have important implications for M. avellanarius conservation. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 648–664. 相似文献
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GIOVANNI NACHTIGALL MAURÍCIO JUAN IGNACIO ARETA MARCOS RICARDO BORNSCHEIN ROBERTO E. REIS 《Zoological Journal of the Linnean Society》2012,166(2):377-432
The family Rhinocryptidae comprises an assemblage of 12 genera and 55 species confined to the Neotropical region. Here we present the first morphology‐based phylogenetic study of the Rhinocryptidae, using 90 anatomical characters (62 osteological, 28 syringeal) scored for all genera of the family and representatives of all families of the infraorder Furnariides. Parsimony analysis of this dataset recovered 7428 equally most‐parsimonious trees. The strict consensus of those trees was completely resolved at the genus level, with the topology (Liosceles (Psilorhamphus ((Eleoscytalopus + Merulaxis) (Acropternis ((Teledromas + Rhinocrypta) ((Pteroptochos + Scelorchilus) (Eugralla (Myornis + Scytalopus)))))))). The monophyly of the Rhinocryptidae as presently understood was recovered with strong support [eight synapomorphies and Bremer support (BS) = 6). Strongly supported internal arrangements included the basal position of the Amazonian genus Liosceles relative to the rest of the family (four synapomorphies, BS = 4), a clade containing Acropternis through Scytalopus (six synapomorphies, BS = 4), and other less inclusive nodes. The main points of congruence between the present morphological phylogeny and previous molecular phylogenetic work on the family were clades supported by six or more synapomorphies and Bremer values of 6–7: Eleoscytalopus + Merulaxis (eight synapomorphies, BS = 6), Scelorchilus + Pteroptochos (seven synapomorphies, BS = 7), Rhinocrypta + Teledromas (seven synapomorphies, BS = 7), and Eugralla + Myornis + Scytalopus (six synapomorphies, BS = 6). A classification derived from the morphological phylogeny is proposed, with new suprageneric taxa being named and diagnosed. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 377–432. 相似文献