8/5/2023 0 Comments Nebela tincta protists![]() Yet the answer to this question remains enigmatic, as efforts to sample the world's biodiversity to date have been limited and thus have precluded direct quantification of global species richness, and because indirect estimates rely on assumptions that have proven highly controversial. The diversity of life is one of the most striking aspects of our planet hence knowing how many species inhabit Earth is among the most fundamental questions in science. The Arcellinida covers a relatively broad range of sizes (mostly between 20 and 250 μm). It can be either self-secreted or composed of recovered and agglutinated material. Arcellinida testate amoebae belong to the eukaryotic supergroup Amoebozoa (Nikolaev et al., 2005) and are morphologically characterised by the presence of lobose pseudopodia and a shell (test) composed from proteinaceous, calcareous or siliceous material. Some morphospecies such as Apodera vas(=Nebela vas), Alocodera cockayni or the whole genus Certesella have been reported as one of the most convincing examples of heterotrophic protists with restricted distributions (Foissner, 2006 Smith and Wilkinson, 2007 Smith et al., 2008). In this group, both cosmopolitan and restricted distribution patterns have been documented. Arcellinida testate amoebae are an excellent group from which to get insights into these questions because they are easy to collect, present in different habitats and they build a shell of characteristic morphology that remains even after the organism’s death. Major questions concerning the diversity and the distribution of protists remain completely unresolved. The consequences for environmental conservation and therefore humanity are also of dire severity and the biodiversity crisis adds unprecedented weight to the barely recognized crisis in taxonomy and systematics.Īlthough widely recognised as essential participants in ecosystem processes and representing a significant part of the Earth’s biodiversity (Clarholm, 1985 Corliss, 2002 Schröter et al., 2003 Falkowski et al., 2004), eukaryotic microorganisms are very poorly understood from evolutionary and biogeographic points of view. These threats to taxonomic resources not only impinge on systematics but all biology: this tragedy jeopardizes the integrity of biological knowledge. Neglect of collections has destroyed countless specimens and threatens millions more. The knowledge held by experienced taxonomists is not being passed on to younger recruits. Preservation of specimens in natural history collections is chronically neglected and support to study and manage collections is very insufficient. Present and future knowledge of the complexities and diversity of the biosphere depends on the integrity of taxonomic resources, vet widespread ignorance and disregard for their fundamental value has created a global crisis. These collections and the human expertise essential to interpret specimens are the taxonomic resources which maintain accurate and verifiable concepts of biological entities. The preservation of specimens in natural history collections is the essential part of the process which builds and maintains biological knowledge. Such knowledge is essential to decide how much and what biodiversity survives human onslaughts. This knowledge is built of interrelated concepts which are ultimately accounted for by biological specimens. ![]() Systematics and taxonomy are essential: they respectively elucidate life's history, and organize and verify biological knowledge. Its assembly will also generate important new insights into the diversification of life and the rules of molecular evolution. When fully developed, a COI identification system will provide a reliable, cost-effective and accessible solution to the current problem of species identification. A model COI profile, based upon the analysis of a single individual from each of 200 closely allied species of lepidopterans, was 100% successful in correctly identifying subsequent specimens. Second, we demonstrate that species-level assignments can be obtained by creating comprehensive COI profiles. First, we demonstrate that COI profiles, derived from the low-density sampling of higher taxonomic categories, ordinarily assign newly analysed taxa to the appropriate phylum or order. We establish that the mitochondrial gene cytochrome c oxidase I (COI) can serve as the core of a global bioidentification system for animals. We are convinced that the sole prospect for a sustainable identification capability lies in the construction of systems that employ DNA sequences as taxon 'barcodes'. Although much biological research depends upon species diagnoses, taxonomic expertise is collapsing.
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