Rodrigo Duno de Stefano

The Morphological and Phylogenetic Distinctions of Coursetia greenmanii (Leguminosae): Taxonomic and Ecological Implications

Abstract A new combination, Coursetia greenmanii (Leguminosae, Papilinioideae, tribe Robinieae), is proposed because analysis of nucleotide sequence data from the nuclear ribosomal internal transcribed spacer region resolves a clade that is phenotypically distinct and ecologically and geographically centered in lowland seasonally dry tropical vegetation of the Yucatan Peninsula region. The well supported monophyly of the ribosomal sequences sampled from Coursetia greenmanii suggests that this species has had a long history independent of its close relatives. Coalescence of intraspecific samples of ribosomal sequences from this geographically confined species is strongly suggestive of an evolutionary persistent small effective population size. This is the general case for species of Coursetia and related genera of the tribe Robinieae. Coalescence of nuclear ribosomal sequences sampled from geographically restricted species in this group further suggests that evolutionary persistence could be the result of high levels of dispersal limitation in seasonally dry Neotropical vegetation that is rich in cacti and other succulent species. This is the ecological setting to which Robinieae shows phylogenetic niche conservatism.

A reappraisal of the turtle-orchids, genus Chelyorchis (Oncidiinae: Orchidaceae): Molecular, phylogenetic, and morphometric approaches1

Abstract A review of live, herbarium, and bibliographic material of Chelyorchis revealed considerable floral variation that appears to be geographically correlated. We assessed whether the genus included one or more taxonomic entities using a morphometric analysis that involved the study of principal component analysis across several floral characters in 70+ specimens, representing both geographical range and morphological variation. To further establish the phylogenetic relationships of Chelyorchis within the Cuitlauzina-clade, and to analyze the evolution of relevant characters, we performed a combined analysis using nrITS, morphological, and gap-coding data, which included only 13 species. Both of our phylogenetic analyses strongly support the genus Chelyorchis as a monophyletic entity that is sister to a clade comprised of the genera Ticoglossum and Rossioglossum. The morphometric evidence strongly suggests that two taxa at the level of species should be recognized, differing primarily in the shape and proportions of the labellum but also in their geographical distribution. A new species, Chelyorchis pardoi, is described and illustrated to accommodate the South American morph. Full description of the new species and iconography of both taxa are provided, and diagnostic features are discussed. The conservation status of the new taxon is assessed against IUCN criteria.

Morphology-inferred Phylogeny and a Revision of the Genus Emmotum (Icacinaceae)1

Abstract Emmotum Desv. ex Ham. is a Neotropical, primarily Amazonian and Guayanan genus (Icacinaceae) of 13 tree or shrub species, including a new species here described from Amazonas, Brazil, E. amazonicum Duno & Carnevali. A cladistic analysis of the 18 taxa of Icacinaceae including 13 of Emmotum was carried out using 41 morphological characters. The single most parsimonious tree shows Emmotum as a monophyletic group, strongly supported by nine synapomorphies, with Poraqueiba Aubl. as the sister group. In addition, two main groups are identified within Emmotum. These two groups laxly correspond with the 1872 classification of Engler: Emmotum sect. Brevistyla Engl. and Emmotum sect. Longistyla Engl. (= section Emmotum). The genus Pogopetalum Benth., synonymous within Emmotum, is lectotypified by P. orbiculatum Benth. (≡ E. orbiculatum (Benth.) Miers). We present a revision of Emmotum with information about nomenclature, distribution, ecology, local names, and uses.

DNA Sequence Variation among Conspecific Accessions of the Legume Coursetia caribaea Reveals Geographically Localized Clades Here Ranked as Species

Abstract Coursetia caribaea is geographically and morphologically the most variable species in the genus Coursetia and in the tribe Robinieae (Leguminosae, Papilionoideae). Because of potentially undetected species, we assessed the phylogenetic relationships among the eight taxonomic varieties of C. caribaea. Sampling included nuclear ribosomal internal transcribed spacer sequences from 489 Robinieae accessions representing all varieties of C. caribaea and 38 of the 40 species of Coursetia, in addition to chloroplast trnD-trnT sequences from 186 accessions. Separate and combined phylogenetic analyses resolved a clade of conspecific accessions of the Bolivian C. caribaea var. astragalina as sister to the central Andean Coursetia grandiflora clade. Also distantly related to Coursetia caribaea var. caribaea accessions were those of the coastal Oaxacan C. caribaea var. pacifica, which formed the sister clade to accessions of the central Andean C. caribaea var. ochroleuca. The estimated mean ages of the stem clades for these three lineages, 11, 7.7, and 7.7 Ma, respectively, contrasted to the estimated mean ages of the corresponding crown clades of 0, 0, and 1.5 Ma. The contrasting stem and crown ages suggest that these taxa, appropriately ranked as species, Coursetia astragalina, Coursetia diversifolia, and Coursetia ochroleuca, each have persisted over evolutionary time frames as distinct geographically localized populations in seasonally dry tropical forests and woodlands.

Testing a species hypothesis with morphometric analysis: Pithecellobium insigne (Leguminosae, Mimosoideae, Ingeae)1

Abstract Morphological information was analyzed to evaluate whether Pithecellobium insigne, usually considered a synonym of Pithecellobium lanceolatum, is a different species. This question was addressed by a multivariate statistical analysis: cluster analysis, principal component analysis, and discriminant analysis using data obtained from herbarium specimens collected in Mexico, Central America, and northern South America. The results support P. insigne as a distinct species from P. lanceolatum. Significant differences with P. lanceolatum are: length of the floral bracts, length of the staminal tube, and thickness of the fruit. Pithecellobium insigne has the largest dimensions for all these features. Hybridization is possible and apparently takes place between both species in the Isthmus of Tehuantepec (Mexico), where populations of both species are parapatric and few specimens with intermediate characters were observed. A key to differentiate both taxa, as well as information about morphology, common names, ecology, conservation, and phenology of P. insigne is also included.

Notes on the Flora of the Yucatán Peninsula IX: A Reappraisal of the Genus Wimmeria (Celastraceae), Including the New Species W. lundelliana

Abstract Wimmeria lundelliana Carnevali, R. Duno, J. L. Tapia & I. Ramírez (Celastraceae) from the Yucatán Peninsula Biotic Province (YPBP) is proposed as a new species. The novelty is described, illustrated, and its affinities discussed. It appears related to W. obtusifolia Standley, also from the Yucatán Peninsula, which is glabrous or glabrescent overall, with proportionally broader and blunter leaves. In comparison, an amplified description and iconography of W. obtusifolia are offered. An epitype is designated for W. obtusifolia to document the fruit morphology. A taxonomic overview of Wimmeria Schlechtendal & Chamisso in the YPBP is presented. The objectives of this paper are (1) to present a synopsis of the genus Wimmeria for the YPBP, (2) to provide a key to species identification, and (3) to describe a new species. An additional objective of this contribution is to provide an amplified description and iconography of W. obtusifolia, particularly of the fruits, which were previously undescribed.