{"id":54,"date":"2016-09-02T13:38:48","date_gmt":"2016-09-02T13:38:48","guid":{"rendered":"http:\/\/sycamore.nybg.org\/science\/projects\/megalastrum\/?post_type=portfolio&p=54"},"modified":"2016-09-26T20:14:36","modified_gmt":"2016-09-26T20:14:36","slug":"phylogeny","status":"publish","type":"portfolio","link":"https:\/\/sweetgum.nybg.org\/science\/projects\/megalastrum\/portfolio\/phylogeny\/","title":{"rendered":"Phylogeny"},"content":{"rendered":"
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Studies using DNA sequences show that Megalastrum<\/i> is monophyletic. This agrees with the morphological characteristics<\/a> that are unique among dryopteroid ferns. Another important result is the identification of the closest relatives to Megalastrum<\/i>. The sister relationship ofRumohra<\/i> to Megalastrum<\/i> was unsuspected, as morphologically, Rumohra<\/i> appears quite different with a creeping rhizome, grooved rachises and costae, and peltate indusia. Sister to the Rumohra<\/i> + Megalastrum<\/i>clade is Lastreopsis<\/i>. This relationship is also new. Lastreopsis<\/i>has been previously thought to be related to Ctenitis<\/i> and Triplophyllum<\/i>, and was formerly placed with these genera in the Tectariaceae (e.g., Moran and Riba, 1995). Uncovering the closest relatives of Megalastrum<\/i> is important, as narrowing the scope of the study will allow for the use of more variable molecular regions that are simply unalignable across the whole of dryopteroid ferns.<\/p>\n

Within the genus, our preliminary studies suggest that all but one of the 18 species in coastal Brazil form a monophyletic group, and that these are sister to the species in Africa-Madagascar. These two clades are in turn sister to the rest of the American species. (Again, these are preliminary results!)<\/p>\n

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Preliminary phylogenetic hypothesis of dryopteroid fern relationships emphasizing those within Megalastrum<\/i>. Tree results from Bayesian analysis of plastid rbcL<\/i> andatpA<\/i> data (~2800 bp). Bolded branches are supported by posterior probabilities \u22650.95. WithinMegalastrum<\/i>, geographic origins are indicated for each sample; note the initial divergence between the paleotropical and neotropical species. (Prepared by E. Schuettpelz).<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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Highly divided leaves appear to be ancestral for Megalastrum<\/i> based on an initial outgroup comparison (the two closest outgroup genera, Rumohra<\/i> and Lastreopsis<\/i>, have highly divided leaves). The basal species in Megalastrum\u2014M. adenopteris<\/i>, M. pulverulentum<\/i>, and M. aripensis<\/i>\u2014also have highly divided leaves. Less-divided leaves (i.e., 1-pinnate-pinnatifid) appear to have evolved twice within the genus: once in M. honestum<\/i> and again inM. biseriale<\/i>.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Studies using DNA sequences show that Megalastrum is monophyletic. This agrees with the morphological characteristics that are unique among dryopteroid ferns. Another important result is the identification of the closest relatives to Megalastrum. The sister relationship ofRumohra to Megalastrum was … Continued<\/a><\/p>\n","protected":false},"author":1,"featured_media":102,"menu_order":0,"comment_status":"open","ping_status":"closed","template":"","meta":[],"portfolio-type":[],"_links":{"self":[{"href":"https:\/\/sweetgum.nybg.org\/science\/projects\/megalastrum\/wp-json\/wp\/v2\/portfolio\/54"}],"collection":[{"href":"https:\/\/sweetgum.nybg.org\/science\/projects\/megalastrum\/wp-json\/wp\/v2\/portfolio"}],"about":[{"href":"https:\/\/sweetgum.nybg.org\/science\/projects\/megalastrum\/wp-json\/wp\/v2\/types\/portfolio"}],"author":[{"embeddable":true,"href":"https:\/\/sweetgum.nybg.org\/science\/projects\/megalastrum\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/sweetgum.nybg.org\/science\/projects\/megalastrum\/wp-json\/wp\/v2\/comments?post=54"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/sweetgum.nybg.org\/science\/projects\/megalastrum\/wp-json\/wp\/v2\/media\/102"}],"wp:attachment":[{"href":"https:\/\/sweetgum.nybg.org\/science\/projects\/megalastrum\/wp-json\/wp\/v2\/media?parent=54"}],"wp:term":[{"taxonomy":"portfolio-type","embeddable":true,"href":"https:\/\/sweetgum.nybg.org\/science\/projects\/megalastrum\/wp-json\/wp\/v2\/portfolio-type?post=54"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}