Tuesday, January 28, 2014

[Orchidology • 2014] Molecular Phylogenetics of Neotropical Cyanaeorchis (Cymbidieae, Epidendroideae, Orchidaceae): Geographical rather than Morphological Similarities plus A New Species | Cyanaeorchis praetermissa from the cerrado biome in central and southeastern Brazil


FIGURE 5. Cyanaeorchis praetermissa. A. Habitat: permanently wet grassland (campo limpo úmido) at the margin of gallery forest in Presidente Kubitschek, Minas Gerais, at the beginning of the rainy season. B. Uprooted plant, showing roots and stem base; remnants of the withered stem from the previous growth season are indicated by an arrow (Batista & Bianchetti 3175, BHCB). C. Inflorescence (Batista et al. 3041, BHCB). D. Flower, partial lateral view (Batista et al. 2218, BHCB).
Cyanaeorchis arundinae. E. Flower, partial lateral view (Batista 312, CEN).
Cyanaeorchis minor. F. Flower, partial lateral view (Klein 124, BHCB).
Scale bars = 5 mm.

Abstract

We investigated the phylogenetic placement of Cyanaeorchis and selected representatives of the tribe Cymbidieae based on nuclear (ITS) and plastid (matK–trnK and rbcL) DNA sequences. Bayesian and parsimony analyses of separate and combined datasets were largely congruent with each other and showed that the Neotropical Cyanaeorchis does not belongs in the predominantly Old World subtribe Eulophiinae, where it has previously been placed. Instead, it is strongly supported as a sister to Grobya in Catasetinae. Because Catasetinae are Neotropical and there are no unequivocal morphological similarities between Cyanaeorchis and other genera in the subtribe, this relationship reflects a geographical rather than morphological similarity and suggest habitat-driven local diversification. Specimens from central Brazil formerly identified as Cyanaeorchis minor are shown to be a distinct species, described here as C. praetermissa. Niche modeling indicates that C. praetermissa and C. minor have different distributions and ecological niches, whereas a third species, C. arundinae has broader climatic tolerances and a distribution that encompasses those of the other two species. The distribution of the genus is also predicted to include Bolivia, the states of Rio de Janeiro, Espirito Santo and several areas in northeastern Brazil, from where no collections are currently known.

Keywords: Cymbidieae; Catasetinae; Eulophiinae; nrITS; matK-trnK; rbcL; phylogeny; niche modeling; new species

FIGURE 5. Cyanaeorchis praetermissa. A. Habitat: permanently wet grassland (campo limpo úmido) at the margin of gallery forest in Presidente Kubitschek, Minas Gerais, at the beginning of the rainy season. B. Uprooted plant. C. Inflorescence. D. Flower.;
Cyanaeorchis arundinae. E. Flower. Cyanaeorchis minor. F. Flower. Scale bars = 5 mm.


Cyanaeorchis praetermissa J.A.N.Bat. & Bianch., sp. nov. 



Distribution and Conservation Status:— Restricted to the cerrado biome in central and southeastern Brazil in the states of Goiás and Minas Gerais and the Federal District (Fig. 4A). The species is known from 13 collections at seven localities. Most collections and some of the larger known populations of the species are from the Federal District, where the species seem to be most threatened. The population at Setor Mansões Park Way has been destroyed, whereas large populations at Santuário Ecologico do Riacho Fundo and Reserva Ecológica do Guará have been severely depleted in the last 20 years due to alterations in habitat quality. Based on the World Conservation Union Red List Categories and Criteria (IUCN 2001), C. praetermissa can be tentatively classified as Vulnerable (VU) (criteria A2ac; B2ab (ii, iii, iv); C2a(i)).

Habitat and Ecology:— Cyanaeorchis praetermissa grows in permanently wet grassland, campo limpo úmido, according to the classification of Ribeiro & Walter (2008), over dark, water-saturated, hydromorphic soil, usually near the border of flooded gallery forests (Fig. 5A) or in veredas (grasslands with buriti palms), 1000–1400 meters above sea level. Vegetative and reproductive growth are associated with rainfall, and blooming occurs at the beginning of the rainy season, from October to early December. Blooming appears to be strictly related to brushfires that occur during the dry season. All collections of the species made by the authors (12 of the 13 known collections) were made in recently burned areas. 

The species is sympatric with, and flowers at about the same time as, other orchid species, such as Veyretia simplex (Grisebach 1864: 641) Szlachetko (1995: 116), Habenaria edwallii Cogniaux (1906 publ. 1907: 275), H. balansae Cogniaux (1906 publ. 1907: 271), Gomesa hydrophila (Barbosa Rodrigues 1877: 92) Chase & Williams (2009: 397), G. barbaceniae (Lindley 1855: 32) Chase & Williams (2009: 395), Epidendrum dendrobioides Thunberg (1818: 17), Cleistes castaneoides Hoehne (1939: 42) and Cyrtopodium fowliei Menezes (1995: 17), all also typically found in habitats with water-saturated soil. Populations of Cyanaeorchis praetermissa usually form compact groups with large number of specimens, whereas C. arundinae and C. minor are usually found as scattered individuals or a few plants.

Etymology:— From Latin, meaning overlooked or neglected, in reference to the new species having been overlooked by previous taxonomists.


Joao Aguiar Nogueira Batista, ANA CAROLINA M. MOTA, KARINA PROITE, LUCIANO DE BEM BIANCHETTI, GUSTAVO A. ROMERO-GONZÁLEZ, HÉCTOR HUERTA, GERARDO A. SALAZAR. 2014. Molecular Phylogenetics of Neotropical Cyanaeorchis (Cymbidieae, Epidendroideae, Orchidaceae): Geographical rather than Morphological Similarities plus A New Species. Phytotaxa. 156(5): 251–272. DOI: http://dx.doi.org/10.11646/phytotaxa.156.5.1 

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