165 research outputs found

    Baujardia mirabilis gen. n., sp n. from pitcher plants and its phylogenetic position within Panagrolaimidae (Nematoda: Rhabditida).

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    Summary -Measurements, line drawings and scanning electromicrographsare provided of Baujardia mirabilis gen. n., sp. n., isolated from pitcher uid of Nepenthes mirabilis from Thailand. The new genus differs from all known nematodes in having two opposing and offset spermatheca-like pouches at the junction of oviduct and uterus. It also differs from most known Rhabditida in having four cephalic setae instead of papillae. Phylogenetic analysis of small subunit rDNA sequence data robustly places the new genus within Panagrolaimidae as a sister taxon to Panagrellus. These unusual nematodes resemble Panagrellus in body size (1.8-2.7 mm in females, 1.3-1.9 mm in males) and in the monodelphic, prodelphic female reproductive system with thickened vaginal walls and prominent postvulval sac. However, they differ from Panagrellus in the characters mentioned above, in their comparatively longer stegostom and in the shape of the male spicules. Because of its aberrant characters, inclusion of this new genus in Panagrolaimidae requires changes to the family diagnosis

    A new nematode genus (Rhabditida: Panagrolaimidae) from pitcher plants

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    During a visit to Tung-Kai Botanical Garden in Trang Province, near the Isthmus of Kra, Southern Thailand, one of us (HS) sampled the liquid contained within the pitchers of the carnvivorous plant Nepenthes cf. mirabilis (Lour.) Druce, in order to obtain some of the peculiar rotifers recorded from such habitats. No rotifers but some unidentifiable bdelloids were found, but the samples contained abundant material of a large nematode together with some diplogasterids. Some of the unique morphological characters of this nematode make its placement difficult. In order to obtain additional information about the nematode’s identity and position in relation to the other known morphologically related taxa, we reconstructed a molecular phylogenetic history of selected taxa, including this nematode, based on the small subunit (ssu) ribosomal DNA. In this paper, we describe this new genus and species from Nepenthes, and present an emended diagnosis of the family Panagrolaimida

    Towards a list of available names in zoology, partim Phylum Rotifera

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    Many, mostly older, names of animal species are nomenclaturally problematic, either because their orthography is unstable, or they cannot be linked reliably to a taxonomic identity, due to the lack of recognisable descriptions and/or types. Yet, they represent available (sensu International Code of Zoological Nomenclature) names and must be taken into account in zoological works. This situation, with available senior, yet dubious names confounding nomenclature, is undesirable. It creates uncertainties at a time when molecular approaches are revolutionizing our concepts of species diversity, and fails us when the current extinction crisis calls for efficient, accurate, and constructive approaches to document, monitor, and conserve biodiversity. The International Code of Zoological Nomenclature (The Code) provides a means to address this issue by restricting availability, application and orthography of names to those included in the List of Available Names in Zoology (LAN). The Code (Art. 79) allows an international body of zoologists in consultation with the Commission to propose a candidate part of the LAN for a major taxonomic field. We explore this possibility for 3570 species-group names of Phylum Rotifera (of which 665 are problematic), by presenting such a candidate Rotifera part of the LAN. The web site of the International Commission on Zoological Nomenclature (http://www.iczn.org) will hold both the candidate list and a forum to facilitate consultation on the candidate list, while the list itself also can already be freely downloaded from three other Internet sites: http://fada.biodiversity. be, http://rotifer.ansp.org/LAN, and www.hausdernatur.at/rotifera. We give here an overview of the general approach and procedures applied in preparation of the candidate list, and anticipate that our effort will promote the process as well as result in a standard list of names for use in taxonomy, the Global Names Architecture and other biodiversity information initiatives

    Baujardia mirabilis gen. n., sp. n. from pitcher plants and its phylogenetic position within Panagrolaimidae (Nematoda: Rhabditida)

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    Summary -Measurements, line drawings and scanning electromicrographsare provided of Baujardia mirabilis gen. n., sp. n., isolated from pitcher uid of Nepenthes mirabilis from Thailand. The new genus differs from all known nematodes in having two opposing and offset spermatheca-like pouches at the junction of oviduct and uterus. It also differs from most known Rhabditida in having four cephalic setae instead of papillae. Phylogenetic analysis of small subunit rDNA sequence data robustly places the new genus within Panagrolaimidae as a sister taxon to Panagrellus. These unusual nematodes resemble Panagrellus in body size (1.8-2.7 mm in females, 1.3-1.9 mm in males) and in the monodelphic, prodelphic female reproductive system with thickened vaginal walls and prominent postvulval sac. However, they differ from Panagrellus in the characters mentioned above, in their comparatively longer stegostom and in the shape of the male spicules. Because of its aberrant characters, inclusion of this new genus in Panagrolaimidae requires changes to the family diagnosis

    New Species in the Old World: Europe as a Frontier in Biodiversity Exploration, a Test Bed for 21st Century Taxonomy

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    The number of described species on the planet is about 1.9 million, with ca. 17,000 new species described annually, mostly from the tropics. However, taxonomy is usually described as a science in crisis, lacking manpower and funding, a politically acknowledged problem known as the Taxonomic Impediment. Using data from the Fauna Europaea database and the Zoological Record, we show that contrary to general belief, developed and heavily-studied parts of the world are important reservoirs of unknown species. In Europe, new species of multicellular terrestrial and freshwater animals are being discovered and named at an unprecedented rate: since the 1950s, more than 770 new species are on average described each year from Europe, which add to the 125,000 terrestrial and freshwater multicellular species already known in this region. There is no sign of having reached a plateau that would allow for the assessment of the magnitude of European biodiversity. More remarkably, over 60% of these new species are described by non-professional taxonomists. Amateurs are recognized as an essential part of the workforce in ecology and astronomy, but the magnitude of non-professional taxonomist contributions to alpha-taxonomy has not been fully realized until now. Our results stress the importance of developing a system that better supports and guides this formidable workforce, as we seek to overcome the Taxonomic Impediment and speed up the process of describing the planetary biodiversity before it is too late

    Fifteen species in one: deciphering the Brachionus plicatilis species complex (Rotifera, Monogononta) through DNA taxonomy

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    Understanding patterns and processes in biological diversity is a critical task given current and rapid environmental change. Such knowledge is even more essential when the taxa under consideration are important ecological and evolutionary models. One of these cases is the monogonont rotifer cryptic species complex Brachionus plicatilis, which is by far the most extensively studied group of rotifers, is widely used in aquaculture, and is known to host a large amount of unresolved diversity. Here we collate a dataset of previously available and newly generated sequences of COI and ITS1 for 1273 isolates of the B. plicatilis complex and apply three approaches in DNA taxonomy (i.e. ABGD, PTP, and GMYC) to identify and provide support for the existence of 15 species within the complex. We used these results to explore phylogenetic signal in morphometric and ecological traits, and to understand correlation among the traits using phylogenetic comparative models. Our results support niche conservatism for some traits (e.g. body length) and phylogenetic plasticity for others (e.g. genome size)

    The European union’s 2010 target: Putting rare species in focus

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    P. 167-185The European Union has adopted the ambitious target of halting the loss of biodiversity by 2010. Several indicators have been proposed to assess progress towards the 2010 target, two of them addressing directly the issue of species decline. In Europe, the Fauna Europaea database gives an insight into the patterns of distribution of a total dataset of 130,000 terrestrial and freshwater species without taxonomic bias, and provide a unique opportunity to assess the feasibility of the 2010 target. It shows that the vast majority of European species are rare, in the sense that they have a restricted range. Considering this, the paper discusses whether the 2010 target indicators really cover the species most at risk of extinction. The analysis of a list of 62 globally extinct European taxa shows that most contemporary extinctions have affected narrow-range taxa or taxa with strict ecological requirements. Indeed, most European species listed as threatened in the IUCN Red List are narrow-range species. Conversely, there are as many wide-range species as narrow-range endemics in the list of protected species in Europe (Bird and Habitat Directives). The subset of biodiversity captured by the 2010 target indicators should be representative of the whole biodiversity in terms of patterns of distribution and abundance. Indicators should not overlook a core characteristic of biodiversity, i.e. the large number of narrow-range species and their intrinsic vulnerability. With ill-selected indicator species, the extinction of narrowrange endemics would go unnoticedS

    The Magnitude of Global Marine Species Diversity

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    Background: The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be discovered. Results: There are ∼226,000 eukaryotic marine species described. More species were described in the past decade (∼20,000) than in any previous one. The number of authors describing new species has been increasing at a faster rate than the number of new species described in the past six decades. We report that there are ∼170,000 synonyms, that 58,000–72,000 species are collected but not yet described, and that 482,000–741,000 more species have yet to be sampled. Molecular methods may add tens of thousands of cryptic species. Thus, there may be 0.7–1.0 million marine species. Past rates of description of new species indicate there may be 0.5 ± 0.2 million marine species. On average 37% (median 31%) of species in over 100 recent field studies around the world might be new to science. Conclusions: Currently, between one-third and two-thirds of marine species may be undescribed, and previous estimates of there being well over one million marine species appear highly unlikely. More species than ever before are being described annually by an increasing number of authors. If the current trend continues, most species will be discovered this century
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