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Taxonomic Implications (taxonomic + implication)
Selected AbstractsAN ASSESSMENT OF VARIABILITY IN THEROPOD DINOSAUR REMAINS FROM THE BATHONIAN (MIDDLE JURASSIC) OF STONESFIELD AND NEW PARK QUARRY, UK AND TAXONOMIC IMPLICATIONS FOR MEGALOSAURUS BUCKLANDII AND ILIOSUCHUS INCOGNITUSPALAEONTOLOGY, Issue 4 2009ROGER B. J. BENSON Abstract:, The assemblage of large-bodied theropod remains from the Taynton Limestone Formation (middle Bathonian) of Stonesfield, Oxfordshire and the Chipping Norton Limestone Formation (lowest Bathonian) of New Park Quarry, Gloucestershire, UK is interpreted as monospecific. An assessment of morphological variation in theropod fossils from these localities reveals no taxonomically-significant variation among remains representing large-bodied individuals. Previous observations of anatomical variation among femora, ilia and scapulocoracoids are attributed to postmortem damage and deformation. Referral of all such material to the first named dinosaur taxon, Megalosaurus bucklandii Mantell, is therefore justified. ,Iliosuchus incognitus' lacks autapomorphies and is a nomen dubium. However, other remains of small-bodied theropods from Stonesfield indicate a minimum of two small-bodied taxa that are distinct from M. bucklandii. [source] Panayiotopoulos Syndrome: An Important Electroclinical Example of Benign Childhood System EpilepsyEPILEPSIA, Issue 6 2007Michael Koutroumanidis Summary:, As a result of the converging evidence from multiple large independent studies, Panayiotopoulos syndrome (PS) is now formally recognized as a distinct clinical entity within the spectrum of benign focal epilepsies of childhood. Clinically, PS is manifested by predominantly autonomic seizures and electrographically with multifocal interictal spikes, while the few published ictal recordings have documented onsets of variable lobar topography. These typical electroclinical features do not allow straightforward assignment to a distinctive cortical area, rendering the term "focal",as we currently understand it,problematic. This is a critical review of the clinical and EEG features of PS, focusing on those characteristics that may shed some light on its so far elusive pathophysiology. We also explore its electroclinical similarities to other idiopathic "focal" epilepsies and its differences to symptomatic focal epilepsies that may also manifest with autonomic ictal symptoms and signs. This methodology allows the formation of a rational hypothesis on the pathophysiology of PS that seems to be emerging as a good model for the so-called "system" (nonsymptomatic) epilepsies, with potentially important taxonomic implications. [source] Historical biogeographical patterns of the species of Bursera (Burseraceae) and their taxonomic implicationsJOURNAL OF BIOGEOGRAPHY, Issue 11 2006David Espinosa Abstract Aim, The plant genus Bursera, with 104 species of trees and shrubs, has been used as a model for biogeographical analyses because of its high species richness and large number of endemic species. The biogeographical patterns of Bursera and their implications for its phylogenetic classification are reviewed in order that some hypotheses on the historical biogeography of tropical Mexico can be proposed. Location,Bursera is found in the south-western USA, most of Mexico, mainly below 1700 m elevation in tropical forests, with some species in xeric shrublands, diversifying along the Pacific slope, Central America, and north-western South America. A few species occur on the Galapagos and Revillagigedo archipelagos, some of which are endemics, whereas in the Antilles species are distributed extensively, with several endemics in the Bahamas, Cuba, Jamaica, and Hispaniola. Methods, Data from specimens in herbaria and the literature were used to construct a matrix of 104 species in 160 areas. Distributional patterns of the species of Bursera were inferred applying track analysis, parsimony analysis of endemicity (PAE), and Brooks parsimony analysis (BPA). Results, Track analysis revealed four individual tracks: (1) a circum-Caribbean track, comprising species of the Bursera simaruba species group; (2) an Antillean track, including species that have been transferred to Commiphora based on their pollen traits; (3) a Mexican Pacific track, including species of the B. fragilis, B. microphylla, and B. fagaroides species groups, called ,cuajiotes'; and (4) a Neotropical Pacific track, including the two species groups assigned to section Bullockia, in which the individual track of the Bursera copallifera species group is nested within the track of the B. glabrifolia species group. The four tracks overlap in a node in the Mexican Pacific slope, where they are highly diversified. PAE allowed us to identify 22 areas of endemism: 12 in Mexico (11 along the Mexican Pacific slope), six in the Antilles, two in Central America, one in South America, and one in the Galapagos. The general area cladogram obtained by BPA has two main clades: one includes the greater Antilles; and the other, 12 Mexican areas of endemism. Main conclusions,Bursera fragilis, B. microphylla, and B. fagaroides species groups can be treated together as a new section within Bursera, sect. Quaxiotea, because they are segregated from the other groups of sect. Bursera based on morphological, anatomical, molecular and geographical evidence. [source] AN SEM-BASED ANALYSIS OF THE MORPHOLOGY, ANATOMY, AND REPRODUCTION OF LITHOTHAMNION TOPHIFORME (ESPER) UNGER (CORALLINALES, RHODOPHYTA), WITH A COMPARATIVE STUDY OF ASSOCIATED NORTH ATLANTIC ARCTIC/SUBARCTIC MELOBESIOIDEAE,JOURNAL OF PHYCOLOGY, Issue 5 2005Walter H. Adey Lithothamnion tophiforme (Esper) Unger is a dominant, arctic, saxicolous species that extends southward, albeit with reduced cover, into the deeper colder waters of the North Atlantic subarctic, where it also occurs in significant rhodolith deposits with L. glaciale. The external appearance of L. tophiforme is distinctive, but typification, anatomy, reproduction, ecology, and biogeography have not been previously analyzed. These topics are now addressed, with extensive use of SEM, in comparison with other North Atlantic arctic and subarctic melobesioid genera and species. The species considered in this article comprise 95% of the coralline biomass of the colder North Atlantic and adjacent arctic (i.e. less than 12° C summer and less than 0° C winter). In the outer thallus region of coralline algae, crust extension proceeds, calcification develops, surface sloughing and grazing occur, and reproductive structures are initiated. Analysis of the ultrastructure of the outer thallus region (epithallium, meristem, and perithallium) of L. tophiforme shows distinctive generic similarities and specific differences from the other Lithothamnion species discussed here. Considerable generic differences from the Clathromorpum and Leptophytum species also encountered in the region considered are highlighted as well. We discuss the functional and taxonomic implications of these distinguishing features and recommend that they be more widely considered in future research on coralline algae to understand more fully the ecology and evolution of the Corallinales. [source] Differentiation of golden-ringed dragonfly Anotogaster sieboldii (Selys, 1854) (Cordulegastridae: Odonata) in the insular East Asia revealed by the mitochondrial gene genealogy with taxonomic implicationsJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 2 2008T. Kiyoshi Abstract Molecular phylogeographical analyses of Anotogaster sieboldii (Selys, 1854) were conducted to reveal the differentiation process of insular populations. The gene genealogy based on 845 bp of the mitochondrial genes (cytochrome oxidase subunit I and subunit II) indicated that A. sieboldii includes two deeply separated lineages. These two major lineages seem to have differentiated in Miocene before the formation of the insular East Asia. One lineage includes three inner clades that correspond to the populations of northern area (the Japanese main islands, Korean Peninsula, Yakushima), Amamioshima and Okinawajima. Populations of Central Ryukyu, including Amamioshima and Okinawajima, might have been divided from the northern populations in early Pleistocene. The other major lineage includes populations of the Yaeyama Group, Taiwan and East China. The former two populations were reconstructed as a reciprocal monophyletic group. Populations of Taiwan and Yaeyama Groups would have been separated from the continental ones in Pleistocene. These two highly divergent lineages should be recognized as distinct species. Furthermore, the mitochondrial lineages revealed six genetically distinct and geographically isolated assemblages: (1) northern populations, (2) Amamioshima, (3) Okinawajima, (4) Yaeyama Group, (5) Taiwan and (6) East China. Zusammenfassung An der Libelle Anotogaster sieboldii wurden molekulare phylogeographische Analysen durchgeführt, um ihre Differenzierungen in Insel-Populationen zu erkennen. Die Gen-Genealogie (basierend auf 845 bp mitochondrialer Gene (COI und COII) zeigte, dass A. sieboldii zwei weit getrennte Abstammungslinien enthält, die sich wahrscheinlich im Miozän vor der Bildung der ostasiatischen Inselwelt differenzierten. Eine Abstammungslinie schließt drei Gruppierungen ein, die den Populationen in den nördlichen Gebieten entsprechen: die japanischen Hauptinseln, die koreanische Halbinsel Yakushima, Amamioshima sowie Okinawajima. Die Populationen von Zentral-Ryukyu, einschließlich Amamioshima und Okinawajima, ist möglicherweise im frühen Pleistozän von den nördlichen Populationen getrennt worden. Die andere größere Abstammungslinie schließt die Populationen der Yaeyama-Gruppe, Taiwan und das Östliche China ein. Zwei dieser Populationen wurden als Teil einer entsprechenden monophyletischen Gruppe rekonstruiert; die Populationen von Taiwan und die Yaeyama-Gruppe sind danach im Pleistozän von den kontinentalen Populationen getrennt worden. Diese zwei sehr differierenden Abstammungslinien sollten als verschiedene Spezies betrachtet werden. Weiterhin werden sechs genetisch verschiedene und geographisch isolierte Gruppierungen deutlich: (1) die nördlichen Populationen, (2) Amamioshima, (3) Okinawajima, (4) die Yaeyama-Gruppe, (5) Taiwan und (6) die Population im östlichen China. [source] Phylogeny of Early Cretaceous spatangoids (Echinodermata: Echinoidea) and taxonomic implicationsPALAEONTOLOGY, Issue 2 2004Loïc Villier A phylogenetic analysis of 36 species provides a test for the taxonomy and the history of Early Cretaceous spatangoids. Most taxonomic units from genera to suborders are consistent with the proposed phylogenetic framework. We retain Hemiasterina, Micrasterina, Hemiasteridae, Schizasteridae, Hemiaster, Heteraster, Mecaster, and Periaster as original monophyletic groups. However, all of these clades originate without the classical apomorphies normally ascribed to them. We suggest a revision of their diagnoses and of the generic attributions of basal species. Some ill-defined, ,primitive', and paraphyletic taxa are recognised: Toxaster, Epiaster, Palhemiaster, and Toxasteridae. Even if they do not have phylogenetic meaning, they are retained here, pending a more complete revision. [source] Phylogeography of spiny mice (genus Acomys, Rodentia: Muridae) from the south-western margin of the Sahara with taxonomic implicationsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009VIOLAINE NICOLAS The present study aims to depict the overall pattern of Acomys history in south-western Sahara. We tested the specific predictions that: (1) several mitochondrial clades can be identified and that they coincide with the described species; (2) successive phases of desert expansion and contraction during the last 3 Myr have resulted in several phases of demographic expansion and population fragmentation in Acomys; and (3) isolation-by-distance occurs. The extent of phylogeographic patterns and molecular genetic diversity (cytochrome b gene and D-loop) were addressed in a survey of 90 individuals of Acomys from 38 localities. Our phylogeographical analyses show a strong genetic structure within western Saharan Acomys, with several phylogroups displaying non-overlapping geographic distributions. Restricted gene flow with isolation-by-distance was recorded and a signal of population expansion was detected within several clades. We suggest that during arid or semi-arid paleoclimatic periods, when large sandy areas were present, Acomys was restricted to rocky massifs, whereas, in more humid periods, when savannah and/or steppe habitat prevailed, this species was able to disperse and to survive outside rocky areas because food resources were abundant. Based on a comprehensive sampling and the use of an integrative approach (i.e. combining cytogenetic, molecular and morphological data), we firmly propose that Acomys airensis should be considered as a junior synonym of Acomys chudeaui. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 29,46. [source] Seed morphology of Linaria species from eastern Spain: identification of species and taxonomic implicationsBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2001JOSÉ GABRIEL SEGARRA Seed morphology of 15 taxa of Linaria from eastern Spain has been studied using stereoscopic and scanning electron microscopy. Four different morphological types are described according to features of the seed-coat surface. The type that includes winged seeded taxa is divided into three subtypes. Seed morphology of each type and subtype is described, compared, illustrated and discussed according to its taxonomic and biological implications. A key to identify the different species or groups of species is also supplied. 2001 The Linnean Society of London [source] | ||||||||||