134 research outputs found

    Bayesian model selection with BAMM: effects of the model prior on the inferred number of diversification shifts

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135965/1/mee312626.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135965/2/mee312626_am.pd

    Post-natal parental care in a Cretaceous diapsid from northeastern China

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    Post-natal parental care seems to have evolved numerous times in vertebrates. Among extant amniotes, it is present in crocodilians, birds, and mammals. However, evidence of this behavior is extremely rare in the fossil record and is only reported for two types of dinosaurs, and a varanopid ‘pelycosaur’. Here we report new evidence for post-natal parental care in Philydrosaurus, a choristodere, from the Yixian Formation of western Liaoning Province, China. We review the fossil record of reproduction in choristoderes, and this represents the oldest record of post-natal parental care in diapsids to our knowledge

    Molecular phylogeny of telenomine egg parasitoids (Hymenoptera: Platygastridae s.l.: Telenominae): evolution of host shifts and implications for classification

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    Parasitoid wasps of the subfamily Telenominae (Hymenoptera: Platygastroidea, Platygastridae) develop as immatures within the eggs of other insects (Lepidoptera, Hemiptera, Diptera and Neuroptera). Rearing records indicate that individual species are restricted to attack hosts within only one of these four main groups. We conducted a phylogenetic analysis of the group using sequence data from multiple genes (18S, 28S, COI, EF-1α) to assess the pattern of shifts among host groups and to test the monophyly of and relationships among genera and species-groups. Telenominae sensu Masner—that is, including only the nominate tribe Telenomini—is not monophyletic. Representatives of the Psix group of genera (Psix Kozlov & Lê and Paratelenomus Dodd) form a monophyletic group that is sister to Gryon Haliday (Scelioninae: Gryonini) and are excluded from the subfamily. The remaining telenomines are monophyletic. The genus Phanuromyia Dodd and the crassiclava group of Telenomus Haliday, both recorded as parasitoids of planthopper eggs (Hemiptera: Auchenorrhyncha, Fulgoroidea), form a monophyletic group that is sister to all other telenomines exclusive of the Psix group. Twenty-nine species of the crassiclava and aradi groups of Telenomus are transferred to Phanuromyia as new combinations. Basal elements of the remaining species are all in groups reared from the eggs of true bugs (Heteroptera), primarily the stink bugs (Pentatomoidea) and seed bugs (Lygaeoidea). A shift to parasitism of lepidopteran eggs evolved within a single clade, occurring either one or two times. From this clade a small group of species, the Telenomus tabanivorus group, subsequently shifted to parasitism of egg masses of true flies (Tabanidae and Stratiomyiidae). Aholcus Kieffer and Platytelenomus Dodd both belong to the clade of lepidopteran parasitoids and are considered as junior synonyms of Telenomus (new synonymy for Aholcus). The monophyletic status of the two core genera, Telenomus and Trissolcus could not be resolved using these data. The phylogenetic pattern of host shifts suggests comparisons among taxa that may be fruitful in elucidating mechanisms by which parasitoids locate their hosts, the proximate factors that determine the host range, and the changes in these factors that influence host changes.Charuwat Taekul, Alejandro A. Valerio, Andrew D. Austin, Hans Klompen and Norman F. Johnso

    Checklist das Spermatophyta do Estado de São Paulo, Brasil

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    Generalized binary tanglegrams: Algorithms and applications

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    Abstract. Several applications require the joint display of two phylogenetic trees whose leaves are matched by inter-tree edges. This issue arises, for example, when comparing gene trees and species trees or when studying the co-speciation of hosts and parasites. The tanglegram layout problem seeks to produce a layout of the two trees that minimizes the number of crossings between the inter-tree edges. This problem is well-studied for the case when the mappings between the leaves of the two trees is one-to-one. However, in typical biological applications, this mapping is seldom one-to-one. In this work we (i) define a generalization of the tanglegram layout problem, called the Generalized Tanglegram Layout (GTL) problem, which allows for arbitrary interconnections between the leaves of the two trees, (ii) provide efficient algorithms for the case when the layout of one tree is fixed, (iii) discuss the fixed parameter tractability and approximability of the GTL problem, (iv) formulate heuristic solutions for the GTL problem, and (v) evaluate our algorithms experimentally.
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