1,721,052 research outputs found
El campo no es un vertedero
No full text¿Quién no disfruta de un paseo por un área natural? Para casi todos supone una recarga de energía y una actividad muy placentera. Lamentablemente, en España es habitual encontrar basuras en cualquier paseo aunque sea corto. En el caso de los vertidos, la magnitud de la basura abandonada es mayor y en estas líneas Jan van der Made detalla la situación del sureste de Madrid y reflexiona sobre ¿qué medidas se pueden tomar para evitar este deterioro?Peer reviewe
Did Human Dispersal into Europe Cause the Continent-Wide Extinction of the Pig Sus strozzii at 1.8 Ma?—Review of a Debate
No full textFor many years, the temporal distribution of pigs in the Pleistocene of Europe drew little attention. This changed when, what became known as, the “suid gap” hypo-thesis was published. Subsequent publications added elements to this hypothesis, while others questioned the hypothesis and even the existence of a “suid gap”. In its most complete form the hypothesis consists of a chain of arguments: (1) pigs are r-selected (a life history trait), (2) therefore fossils of their deciduous teeth are particularly abundant, (3) because being r-selected, pigs are abundant, (4) sites without pig fossils are sure indicators of their absence, (5) at 1.8 Ma, humans dispersed into Europe driving Sus strozzii to extinction in all the continent by competitive displacement, but not in the Middle East, (6) around 1.2 Ma pigs appeared again in Europe, either Sus strozzii, coming from the Middle East, or another species. The proposed link between human and pig ecology increased the interest of this hypothesis. Recently parts of this hypothesis were questioned and a polemic arose. It is the aim of this paper to review the literature and arguments used in favour and against this “suid gap” hypothesis. The hypothesis is rejected, but the life history traits of pigs may prove to be of interest for comparison with humans
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Biogeography and climatic change as a context to human dispersal out of Africa and within Eurasia
No full textThe dispersal of the genus Homo occurred against a background of continuous environmental change. Here, dispersals of large mammals through the Levantine Corridor and into Western Europe and Java are studied and compared to existing records of climatic change and dispersals of early humans and lithic industry. The first human dispersal (with Oldowan lithic industry) out of Africa, around or shortly before 1.8 Ma may have been triggered by biological evolution and increased social organisation, rather than environmental change. After that event, increasing aridity led to decreased faunal exchange between Africa and Eurasia and may have isolated the human populations of Africa and Africa. Southern (Java) and Eastern Asia (China) also seem to have been isolated. Human dispersal into Western Europe may have been limited by closed environments in Central Europe until about 1.2 Ma ago, when faunal dispersal into Europe suggests the cyclic spread of open environments to the west. Acheulean technology originated in Africa, some 1.6-1.5 Ma ago, but its dispersal into Eurasia may have been obstructed by an arid Southwest Asia, until broadly about 0.9 Ma ago, when faunal exchange suggests that the area became temporarily less dry. By 0.6-0.5 Ma ago it reached Europe. © 2010 Elsevier Ltd.This paper benefited from discussions with members of the Atapuerca team and many others, particularly John de Vos. The results on biogeography presented here are a contribution to projects BOS2003-08938-C03-02 and CGL2008-03881 of the Ministerio de Ciencia y Inovación and NL-TAF-4053 of Synthesys.Peer Reviewe
An updated range chart for the Oligocene to recent west Eurasian Suoidea. Variation in species richness
No full textNOW 25th Anniversary Meeting Sabadell (Barcelona), 16–18 November 2022 Organized by: Institut Català de Paleontologia Miquel CrusafontThe first intent to publish a complete range chart for the European Suoidea was over 30 years ago (Van der Made, 1990). There have been important advances in dating and many papers have dealt with the systematics, nomenclature, and temporal distribution of these Suoidea. Here, this information is united, and an update is presented. This range-chart also shows in a compact way the taxonomy and nomenclature as used in the NOW database. The ages of the MN and MP units and a Spanish biozonation follow Hilgen et al. (2012) and Van Dam et al. (2006). Where the boundaries are drawn obliquely, this reflects the range of their uncertainty for the Spanish biozones, but only partially so for the MN units, because many of the criteria used for the correlation of the MN units are diachronic. In most cases, presence in a MN unit is marked as in the whole unit, while in other cases additional information (local biostratigraphy, magnetostratigraphy) shows a taxon to be present only in part of a MN unit. This is also the case when two chrono(sub)species of a lineage occur in the same biozone. These problems are dealt with as by Van der Made (2020). Localities in Anatolia are included (as also in the earlier range-chart), as well as from Kazakhstan and Israel, parts of west Eurasia that are not Europe. The differences with the range chart from 1990 are shown in red . A name written in red was not applied in 1990. A red line indicates that the species was not recognized as a distinct species. A red oblique line indicates a newly proposed ancestor-descendant relationship. Corrections to temporal ranges are not indicated. Most of these differences and those with publications of colleagues are discussed elsewhere (e.g., Van der Made, 2020). In 1990, I followed Ginsburg (1974) for the Palaeochoeridae. Recently, many new names have been proposed for the Palaeochoeridae, but see the discussion by Van der Made (2020). There are two types of Oligocene Palaeochoeridae. Doliochoerus (=Propalaeochoerus) has narrow upper molars with convergent lingual roots and with the distal cusplet on the m1¿m2 close to the hypoconid and includes Doliochoerus leptodon (=Doliochoerus quercyi) and its likely descendant Doliochoerus elaverensis, which has a longer third molar. Palaeochoerus has wide upper molars with divergent lingual roots that are connected with a bony plate and m1 m2 with the distal cusplet in the middle. It includes Palaeochoerus aquensis and its likely smaller descendant Palaeochoerus typus. Whereas the range chart of 1990 had just over 40 species and subspecies, the updated one has over 60. The diversity is lower in the Oligocene than in the Middle Miocene, but the temporal ranges are longer. This could reflect the lesser density of fossils, a slower rate of evolution, or lower temperatures and atmospheric pCO2. Species diversity parallels that of the Plio-Pleistocene, when temperatures and pCO2 declined.Part of R+D+I project PID2020-117289GB-I00Peer reviewe
The Suoidea from the Middle Miocene of Gračanica (Bugojno Basin, Bosnia and Herzegovina)—evolution, taxononomy, and biostratigraphy
No full textThe Suoidea from Gračanica in the Bugojno Basin (Bosnia and Herzegovina) are assigned to Choeromorus lemuroides (previously Taucanamo sansaniense) (Taucanaminae, Palaeochoeridae), Bunolistriodon latidens (Listriodontinae, Suidae), and Conohyus simorrensis (Tetraconodontinae, Suidae). These belong to three anagenetic lineages, known from Western Europe to Anatolia. The fossils from Gračanica and these lineages are described in detail. Biostratigraphic correlations in an area extending from Western Europe to Anatolia are proposed on the basis of these lineages. These correlations are consistent with known independent age estimates of the large mammal localities in the different areas. Because the Suoidea from Gračanica belong to groups which have suffered from recent taxonomic inflation, their systematics has been discussed for a correct classification.This paper benefited from projects Synthesys GB-TAF-4119 and AT-TAF-3663 and from projects CGL2004-04169/BTE, CGL2008-03881 of the Spanish Ministry of Science, and CGL20l565387-C3-3-P from the Spanish Ministery of Economy and Competitiveness
Las extinciones en el pasado, previsión para el futuro
No full textLas cinco grandes extinciones han sido hace 444, 375, 251, 200 y 66 millones de años, cuando se extinguieron entre el 75 y 96% de las especies. Según algunos, estamos viviendo la sexta, que ha afectado al mamut , y que va en aumento. A lo largo de los años han ido ocurriendo numerosos pequeños eventos de extinción que nos pueden dar pistas sobre el futuro desarrollo de la presente ola. La crisis del Vallesiense fue reconocida por primera vez en base a fósiles del Vallés-Penedés (Cataluña). Se extinguieron los homínidos primitivos que vivían en Europa y otros animales, como ocho especies de jabalíes. Europa nunca ha recuperado esta biodiversidad. Desaparecieron también plantas tropicales o subtropicales. Esto fue provocado por una fuerte bajada de la temperatura y un aumento de la estacionalidad, concentrando la producción de fruta en una parte del año y provocando así la extinción de animales frugívoros, como estos homínidos y algunas especies de jabalí
On the origin of Metridiochoerus and Potamochoerus.
No full textThe African fossil Suidae were studied intensively, but their possible affinities with Eurasian suids much less so. Metridiochoerus is either assumed to have descended from a ¿hypothetical Sus-like ancestor¿ (e.g. Cooke, 1978; Bishop, 2010), or to have a close relationship to Kolpochoerus or Potamochoerus (e.g. Harris & White, 1979). Shared dental characters allow to trace the origin of Metridiochoerus to certain Eurasian suids. In the literature on African suids, the living Potamochoerus is either traced back to P. afarensis (e.g. Harris & White, 1979; Bishop, 2010), or that species is placed in Kolpochoerus, while Potamochoerus is assumed to have a ¿hypothetical Sus-like ancestor¿ (e.g. Cooke, 1978). As a result the first appearance of the genus varies widely from the early Late Pliocene (Harris & White, 1979; Harris & Liu, 2007; Bishop, 2010) to Middle Pleistocene (Cooke, 1985) or Late Pleistocene (White, 1996). Stehlin (1899-1900) may have been the first to place fossil species from Europe and Asia in the genus Potamochoerus. Pilgrim (1926) included some of these species in the new, supposedly ancestral genus, Propotamochoerus, named several new species in that genus and two in Potamochoerus on the basis of Indian material. Colbert (1935) traced the living Potamochoerus back to one of these two species. Hooijer (1954) believed Celebochoerus from Sulawesi to be closely related to Potamochoerus. The European latest Miocene to Early Pliocene Propotamochoerus provincialis, is occasionally placed in Potamochoerus (Stehlin, 1899-1900; Guérin, 1996). Still other Chinese (e.g. Lee, 1963; Chang, 1974; Han, 1987), Indian (Verma et al., 1981) and European species (Arribas & Garrido, 2008) have been placed in Potamochoerus. Some consider the temporal range of Potamochoerus in Asia to be from the Middle Miocene to Late Pleistocene (Harris & Liu, 2007). The affinities of these taxa will be discussed.Peer Reviewe
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