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Morphological Convergence (morphological + convergence)
Selected AbstractsMorphological convergence of pharyngeal jaw structure in durophagous perciform fishBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2003JUSTIN GRUBICH This study investigated the ecomorphology of pharyngeal jaw structure and durophagy in three families of marine teleosts: the Sciaenidae, Haemulidae and Carangidae. Regressions of the bone and muscle mass of pharyngeal jaws were generated to elucidate the differences associated with eating hard-bodied and soft-bodied prey; within-family comparisons revealed significant differences in masses of bones and muscles involved with processing the former. Generally, the durophagous species ,Trachinotus carolinus (Carangidae), Pogonias cromis (Sciaenidae) and Anisotremus surinamensis (Haemulidae) , had heavier and stronger pharyngeal toothplates and larger protractor pectoralis muscles, with masses of these musculoskeletal elements ranging from five times to nearly an order of magnitude larger than those of their soft-prey feeding relatives. Pogonias cromis and T. carolinus demonstrate convergence in the ontogeny and morphological modification of the pharyngeal toothplates and protractor pectoralis muscles that enhance crushing ability. In the Haemulidae, moderate size increases in a few pharyngeal jaw elements (and larger overall body size in A. surinamensis) are sufficient for durophagy. Morphospace analysis of six species from the three families illustrates the strong functional association between the biomechanical properties of prey and the relative sizes of biting and transport mechanisms. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 80, 147,165. [source] CONVERGENCE AND THE MULTIDIMENSIONAL NICHEEVOLUTION, Issue 2 2005Luke J. Harmon Abstract Convergent evolution has played an important role in the development of the ecological niche concept. We investigated patterns of convergent and divergent evolution of Caribbean Anolis lizards. These lizards diversified independently on each of the islands of the Greater Antilles, producing the same set of habitat specialists on each island. Using a phylogenetic comparative framework, we examined patterns of morphological convergence in five functionally distinct sets of morphological characters: body size, body shape, head shape, lamella number, and sexual size dimorphism. We find evidence for convergence among members of the habitat specialist types for each of these five datasets. Furthermore, the patterns of convergence differ among at least four of the five datasets; habitat specialists that are similar for one set of characters are often greatly different for another. This suggests that the habitat specialist niches into which these anoles have evolved are multidimensional, involving several distinct and independent aspects of morphology. [source] 120 Exploration of Morphological Variation Within the Genus Pediastrum Meyen 1829 (Chlorophyceae, Chlorophyta)JOURNAL OF PHYCOLOGY, Issue 2003H. A. McManus Monographic works on the green algal genus, Pediastrum Meyen 1829 (Chlorophyceae, Chlorophyta), have described species, varieties and forms based on such characteristics as the size and shape of the marginal cells, pattern of cell wall sculpturing and extent of cell wall sculpturing. Depending on the author, the number of taxa assigned to the genus Pediastrum varies. Due to the lack of quantitative value to these characteristics, it has been difficult for other researchers to assign appropriate taxonomy to wild isolates. A molecular phylogeny including multiple strains from both culture collections and wild samples confirms relationships found by previous molecular studies on fewer taxa, in which the family Hydrodictyaceae forms a monophyletic group within the Sphaeropleales, and that the genera Hydrodictyon and Sorastrum are derived from Pediastrum. Hydrodicyton forms a monophyletic clade and consists of three species, H. reticulatum, H. africanum, and H. patenaeforme. Multiple isolates of H. reticulatum reveal little genetic variation between different geographic localities. Inclusion of wild isolates permits a more thorough exploration of morphological variation within the genus Pediastrum, and what characters may be taxonomically informative, particularly in the species P. boryanum and P. duplex. Wild isolates sampled from different areas also offers information regarding geographic variation and potential morphological convergence. [source] Ultrasequencing of the meiofaunal biosphere: practice, pitfalls and promisesMOLECULAR ECOLOGY, Issue 2010S. CREER Abstract Biodiversity assessment is the key to understanding the relationship between biodiversity and ecosystem functioning, but there is a well-acknowledged biodiversity identification gap related to eukaryotic meiofaunal organisms. Meiofaunal identification is confounded by the small size of taxa, morphological convergence and intraspecific variation. However, the most important restricting factor in meiofaunal ecological research is the mismatch between diversity and the number of taxonomists that are able to simultaneously identify and catalogue meiofaunal diversity. Accordingly, a molecular operational taxonomic unit (MOTU)-based approach has been advocated for en mass meiofaunal biodiversity assessment, but it has been restricted by the lack of throughput afforded by chain termination sequencing. Contemporary pyrosequencing offers a solution to this problem in the form of environmental metagenetic analyses, but this represents a novel field of biodiversity assessment. Here, we provide an overview of meiofaunal metagenetic analyses, ranging from sample preservation and DNA extraction to PCR, sequencing and the bioinformatic interrogation of multiple, independent samples using 454 Roche sequencing platforms. We report two examples of environmental metagenetic nuclear small subunit 18S (nSSU) analyses of marine and tropical rainforest habitats and provide critical appraisals of the level of putative recombinant DNA molecules (chimeras) in metagenetic data sets. Following stringent quality control measures, environmental metagenetic analyses achieve MOTU formation across the eukaryote domain of life at a fraction of the time and cost of traditional approaches. The effectiveness of Roche 454 sequencing brings substantial advantages to studies aiming to elucidate the molecular genetic richness of not only meiofaunal, but also all complex eukaryotic communities. [source] The ecological morphology of darter fishes (Percidae: Etheostomatinae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2010ROSE L. CARLSON Darters are a species-rich radiation of small benthic and benthic-associated stream fishes that comprise approximately 20% of the diversity of the North American freshwater fish fauna. Here, we gather data from 165, or 87%, of described species and use this information to characterize the morphological diversity of the darter radiation. We focus on characters of the oral jaws known to function in prey capture and consumption in other perciform taxa in order to explicitly link morphological diversity to ecological diversity. In addition to a quantitative description of the morphospace occupied by darters, we identify several instances of significant morphological convergence. We also describe three groups of darter species that exhibit unusual jaw morphologies that are used in previously undescribed prey capture behaviours. Despite these new ecomorphs, we find that darters exhibit relatively low variation in trophic morphology when compared with two other radiations of teleost fishes, and that the observed variation is related more to differences in microhabitat use than to differences in prey type. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 30,45. [source] Reconstructing the origins of praying mantises (Dictyoptera, Mantodea): the roles of Gondwanan vicariance and morphological convergenceCLADISTICS, Issue 5 2009Gavin J. Svenson A comprehensive taxonomic sampling of Mantodea (praying mantises), covering virtually all higher-level groups, was assembled to reconstruct the phylogeny of the order. Sequence data were generated from five mitochondrial and four nuclear loci (12S rRNA, 16S rRNA, 18S rRNA, 28S rRNA, Histone III, Cytochrome Oxidase I & II, NADH dehydrogenase subunit 4, and Wingless) for 329 mantis exemplars along with seven cockroach and eight termite species. Only seven of 14 families, 14 of 33 subfamilies, and seven of 14 tribes were recovered as monophyletic, indicating that phylogeny is largely incongruent with classification. Mapping biogeographical regions on the phylogeny demonstrated that our results adhere closer to biogeographical distributions than to classification. Specific patterns in distribution suggest that major morphological convergences have confounded taxonomists' ability to reconstruct natural groups. A major revision of higher-level relationships is in order through a comprehensive investigation of morphology and molecular data. We found that major mantis lineages diverged prior to and during the isolation of geographical regions and subsequent ecomorphic specializations within these regions may have led to convergences in morphology. Divergence time estimation places the origin of Mantodea at the beginning of the Jurassic with most modern mantises originating on Gondwana in the Cretaceous. The first major divergence among modern mantises occurred as a result of the north,south splitting of South America and Africa. Subsequent divergences resulted from the breakup of Gondwana. The position of the Indian subcontinent appears to be central to the diversification of Afrotropical and Indomalayan mantises while Antarctica may have served as the conduit for the mantis invasions into South America and Australasia. When India separated from Antarctica and drifted north it distributed mantis lineages back into the Afrotropics and carried a diverse taxonomic assemblage to Asia. [source] | |||||||||||||||||||