Phylogenetic analyses and morphological characteristics support the description of a second species of Tridimeris (Annonaceae)

Desmopsisterriflora, an extraordinary new species of Annonaceae with flagelliflory

Flagelliflory refers to the production of inflorescences exclusively on long, whip-like branches which emerge from the main trunk and extend along the ground or below it. It is the rarest type of cauliflory and only a few cases have been reported in the world. Here, a new species of Annonaceae with flagelliflory is described and illustrated. The phylogenetic relationships of the new species were inferred using a hybrid-capture phylogenomic approach and we present some notes on its reproductive ecology and pollen characteristics. The new species, namely Desmopsisterriflorasp. nov., is part of a clade composed of Mexican species of Stenanona with long, awned petals. Desmopsisterriflora is distinguished by its flageliflorous inflorescences, basely fused sepals, thick red petals, reduced number of ovules per carpel, pollen grains with a weakly rugulate to fossulate exine ornamentation, and its globose, apiculate fruits with a woody testa. The morphological characteristics of the flagella suggest that these are specialized branches rather than inflorescences, and the absence of ramiflory implies an exclusively reproductive function. The flowers are infrequently visited by insects, their potential pollinators being flies and ants.

A jungle tale: Molecular phylogeny and divergence time estimates of the Desmopsis-Stenanona clade (Annonaceae) in Mesoamerica

The predominantly Asian tribe Miliuseae (Annonaceae) includes over 37 Neotropical species that are mainly distributed across Mesoamerica, from southern Mexico to northern Colombia. The tremendous ecological and morphological diversity of this clade, including ramiflory, cauliflory, flagelliflory, and clonality, suggests adaptive radiation. Despite the spectacular phenotypic divergence of this clade, little is known about its phylogenetic and evolutionary history. In this study we used a nuclear DNA marker and seven chloroplast markers, and maximum parsimony, maximum likelihood and Bayesian inference methods to reconstruct a comprehensive time-calibrated phylogeny of tribe Miliuseae, especially focusing on the Desmopsis-Stenanona clade. We also perform ancestral area reconstructions to infer the biogeographic history of this group. Finally, we use ecological niche modeling, lineage distribution models, and niche overlap tests to assess whether geographic isolation and ecological specialization influenced the diversification of lineages within this clade. We reconstructed a monophyletic Miliuseae that is divided into two strongly supported clades: (i) a Sapranthus-Tridimeris clade and (ii) a Desmopsis-Stenanona clade. The colonization of the Neotropics and subsequent diversification of Neotropical Miliuseae seems to have been associated with the expansion of the boreotropical forests during the late Eocene and their subsequent fragmentation and southern displacement. Further speciation within Neotropical Miliuseae out of the Maya block seems to have occurred during the last 15 million years. Lastly, the geographic structuring of major lineages of the Desmopsis-Stenanona clade seems to have followed a climatic gradient, supporting the hypothesis that morphological differentiation between closely related species resulted from both long-term isolation between geographic ranges and adaptation to environmental conditions.

A new species of big-eared climbing rat, genus Ototylomys (Cricetidae: Tylomyinae), from Chiapas, Mexico

An allopatric population of big-eared climbing rats (Ototylomys) from the Northern Highlands of Chiapas, Mexico, is described as a new species. The new taxon is part of a unique montane rainforest community that includes several other endemic species in the limited geographic range between the Río Grijalva and the Central Depression of Chiapas. Several cranial, external, and molecular characters distinguish this new species of big-eared climbing rat from its more widely distributed congener, Ototylomys phyllotis. We performed principal component and discriminate function analyses of cranial measurements, and found that specimens of the new species consistently could be distinguished from other Ototylomys with strong statistical support. Compared with exemplars of Ototylomys from elsewhere in their range, the new species possesses a karyotype that differs by 3 additional biarmed chromosome pairs, is fixed or nearly fixed for distinct electromorphs at 12 allozyme loci, and the mean genetic distance exceeds 14%, based on comparisons of the mitochondrial cytochrome b gene between the new species of Ototylomys and representatives of O. phyllotis. The restricted distribution in montane karst rainforest suggests that the species and its habitat may be a matter of conservation concern.

Una población alopátrica de rata orejuda trepadora (Ototylomys) de las Tierras Altas del Norte de Chiapas, México se describe como una nueva especie. El nuevo taxón es parte de una comunidad única de bosque lluvioso montano que incluye varias especies endémicas en el área de distribución geográfica limitada entre el Río Grijalva y la Depresión Central de Chiapas. Varios caracteres craneales, externos, y moleculares distinguen la nueva rata orejuda trepadora de su congénere más ampliamente distribuido, Ototylomys phyllotis. Se realizaron análisis de componentes principales y de función discriminante de los caracteres craneales, y se encontró que los especímenes de La Pera fueron consistentemente distinguidos de otros Ototylomys con un fuerte soporte estadístico. En comparación con ejemplares de Ototylomys del rango, la nueva especie posee un cariotipo que difiere por 3 pares adicionales de cromosomas biarmados, está fijo o casi fijo por distintos electromorfos en 12 loci alozímicos. Adicionalmente, la media de la distancia genética comparada del gen mitochondrial citocromo b entre la nueva especie de Ototylomys y representantes de O. phyllotis, excede el 14%. La distribución restringida en el bosque lluvioso montano kárstico sugiere que la especie y su hábitat pueden ser de importancia para la conservación.

A mega-phylogeny of the Annonaceae: taxonomic placement of five enigmatic genera and support for a new tribe, Phoenicantheae

The Annonaceae, the largest family in the early-divergent order Magnoliales, comprises 107 genera and c. 2,400 species. Previous molecular phylogenetic studies targeting different taxa have generated large quantities of partially overlapping DNA sequence data for many species, although a large-scale phylogeny based on the maximum number of representatives has never been reconstructed. We use a supermatrix of eight chloroplast markers (rbcL, matK, ndhF, psbA-trnH, trnL-F, atpB-rbcL, trnS-G and ycf1) to reconstruct the most comprehensive tree to date, including 705 species (29%) from 105 genera (98%). This provides novel insights into the relationships of five enigmatic genera (Bocagea, Boutiquea, Cardiopetalum, Duckeanthus and Phoenicanthus). Fifteen main clades are retrieved in subfamilies Annonoideae and Malmeoideae collectively, 14 of which correspond with currently recognised tribes. Phoenicanthus cannot be accommodated in any existing tribe, however: it is retrieved as sister to a clade comprising the tribes Dendrokingstonieae, Monocarpieae and Miliuseae, and we therefore validate a new tribe, Phoenicantheae. Our results provide strong support for many previously recognised groups, but also indicate non-monophyly of several genera (Desmopsis, Friesodielsia, Klarobelia, Oxandra, Piptostigma and Stenanona). The relationships of these non-monophyletic genera-and two other genera (Froesiodendron and Melodorum) not yet sampled-are discussed, with recommendations for future research.

Revisions of Ruizodendron and Pseudephedranthus (Annonaceae) including a new species and an overview of most up-to-date revisions of Neotropical Annonaceae genera

We present revisions of the Neotropical genera Ruizodendron and Pseudephedranthus (Annonaceae). Ruizodendron includes a single species R. ovale. Pseudephedranthus now comprises two species, with the description of the new species P. enigmaticussp. nov. extending the range of the genus beyond the Upper Rio Negro region of Brazil (Amazonas) and adjacent Venezuela (P. fragrans), to include Guyana, Suriname, and the Brazilian state of Pará. An overview is provided of current revisions of Neotropical Annonaceae genera that will aid in accessing proper species information for this frequently encountered tropical rain forest family.