Carl E. Lewis

A phylogenetic analysis of tribe Areceae (Arecaceae) using two low-copy nuclear genes

Abstract. A phylogenetic study of the largest tribe of palms, the Areceae, was conducted using sequences of two low-copy nuclear genes. Previous morphological and plastid DNA studies have not supported the monophyly of the tribe, but have placed its members in a large clade that includes the monophyletic tribes Geonomeae, Cocoeae, Podococceae, and Hyophorbeae. We analyzed this large clade to test the monophyly of tribe Areceae with nuclear data, to explore relationships among its subtribes, and to identify other monophyletic groups. For 54 palm species, including members of all 17 subtribes of tribe Areceae, we sequenced regions of the malate synthase (MS) and phosphoribulokinase (PRK) genes. Simultaneous analysis of these regions revealed 52 shortest trees, all of which resolved tribe Areceae as polyphyletic. Subtribes Iguanurinae, Dypsidinae, Oncospermatinae, and Arecinae were also resolved as polyphyletic. A clade of Indo-Pacific taxa was resolved with strong support, and would be a suitable target for more focused study.

Phylogenetic relationships among arecoid palms (Arecaceae: Arecoideae)

BACKGROUND AND AIMS The Arecoideae is the largest and most diverse of the five subfamilies of palms (Arecaceae/Palmae), containing >50 % of the species in the family. Despite its importance, phylogenetic relationships among Arecoideae are poorly understood. Here the most densely sampled phylogenetic analysis of Arecoideae available to date is presented. The results are used to test the current classification of the subfamily and to identify priority areas for future research. METHODS DNA sequence data for the low-copy nuclear genes PRK and RPB2 were collected from 190 palm species, covering 103 (96 %) genera of Arecoideae. The data were analysed using the parsimony ratchet, maximum likelihood, and both likelihood and parsimony bootstrapping. KEY RESULTS AND CONCLUSIONS Despite the recovery of paralogues and pseudogenes in a small number of taxa, PRK and RPB2 were both highly informative, producing well-resolved phylogenetic trees with many nodes well supported by bootstrap analyses. Simultaneous analyses of the combined data sets provided additional resolution and support. Two areas of incongruence between PRK and RPB2 were strongly supported by the bootstrap relating to the placement of tribes Chamaedoreeae, Iriarteeae and Reinhardtieae; the causes of this incongruence remain uncertain. The current classification within Arecoideae was strongly supported by the present data. Of the 14 tribes and 14 sub-tribes in the classification, only five sub-tribes from tribe Areceae (Basseliniinae, Linospadicinae, Oncospermatinae, Rhopalostylidinae and Verschaffeltiinae) failed to receive support. Three major higher level clades were strongly supported: (1) the RRC clade (Roystoneeae, Reinhardtieae and Cocoseae), (2) the POS clade (Podococceae, Oranieae and Sclerospermeae) and (3) the core arecoid clade (Areceae, Euterpeae, Geonomateae, Leopoldinieae, Manicarieae and Pelagodoxeae). However, new data sources are required to elucidate ambiguities that remain in phylogenetic relationships among and within the major groups of Arecoideae, as well as within the Areceae, the largest tribe in the palm family.

Molecular Phylogenetics of Tribe Geonomeae (Arecaceae) Using Nuclear DNA Sequences of Phosphoribulokinase and RNA Polymerase II

Abstract Phylogenetic analyses were performed on six genera and 46 species of the Neotropical palm tribe Geonomeae (subfamily Arecoideae) and outgroups composed of 14 species from the Arecoideae, two from the Ceroxyloideae, and one from the Phytelephantoideae. The analyses were based on two low copy nuclear DNA sequences from the genes encoding phosphoribulokinase and RNA polymerase II. The two data sets did not appear to conflict and were analyzed separately and in combination. Our results added support to the previously reported monophyly of the tribe. The basal node of the tribe was polytomous containing the genera Welfia and Pholidostachys and a clade consisting of the rest of the Geonomeae. Pholidostachys formed a monophyletic group. The currently accepted genera Calyptronoma and Calyptrogyne formed a well-supported clade with Calyptronoma resolved as paraphyletic to Calyptrogyne. Geonoma formed a strongly supported monophyletic group consisting of two main clades. Geonoma section Taenianthera was not monophyletic but a group of three high-elevation Geonoma species was resolved.

Evolution of lamina anatomy in the palm family (Arecaceae)

The unique properties of tree building in Arecaceae strongly constrain their architectural lability. Potentially compensating for this limitation, the extensive diversification of leaf anatomical structure within palms involves many characters whose alternate states may confer disparate mechanical or physiological capabilities. In the context of a recent global palm phylogeny, we analyzed the evolution of 10 such lamina anatomical characters and leaf morphology of 161 genera, conducting parsimony and maximum likelihood ancestral state reconstructions, as well as tests of correlated evolution. Lamina morphology evolves independently from anatomy. Although many characters do optimize as synapomorphic for major clades, anatomical evolution is highly homoplasious. Nevertheless, it is not random: analyses indicate the recurrent evolution of different cohorts of correlated character states. Notable are two surface layer (epidermis and hypodermis) types: (1) a parallel-laminated type of rectangular epidermal cells with sinuous anticlinal walls, with fibers present in the hypodermis and (2) a cross-laminated type of hexagonal cells in both layers. Correlated with the cross-laminated type is a remarkable decrease in the volume fraction of fibers, accompanied by changes in the architecture and sheath cell type of the transverse veins. We discuss these and other major patterns of anatomical evolution in relation to their biomechanical and ecophysiological significance.

Seed Plant Genera Endemic to the Caribbean Island Biodiversity Hotspot: A Review and a Molecular Phylogenetic Perspective

The Caribbean Island Biodiversity Hotspot is composed primarily of the Bahamas and Greater and Lesser Antilles. A total of 180 genera (727 spp., ca. 9% of the species endemic to the Antilles) are restricted to this hotspot. Most of these genera are unispecific (51%), a pattern that is also found on other islands of the world. The majority of the endemic genera belong to the “Core Eudicot” clade, and they were published in two time periods (1854–1878 and 1904–1928). There are molecular phylogenies available for 63 of the endemic genera. However, phylogenetic reconstructions of only 21 genera are based on more than one independent DNA region and have well-supported clades and good taxonomic sampling. Six of the endemic genera form part of early-branching groups. We could not infer biogeographical conclusions from the molecular phylogenies of most of the endemic genera (43: 68%). There is an urgent need for (1) additional field studies to learn the conservation status of these genera, (2) effective protection of the habitats where the most endangered genera occur, and (3) additional biological and systematic studies of the least understood genera.

The conservation status of West Indian palms (Arecaceae)

The conservation status of 134 species, sub- species and varieties of West Indian palms (Arecaceae) is assessed and reviewed, based on field studies and current literature. We find that 90% of the palm taxa of the West Indies are endemic. Using the IUCN Red List categories one species is categorized as Extinct, 11 taxa as Critically Endangered, 19 as Endangered, and 21 as Vulnerable. Fifty-seven taxa are classified as Least Concern. Twenty-five taxa are Data Deficient, an indica- tion that additional field studies are urgently needed. The 11 Critically Endangered taxa warrant immediate conservation action; some are currently the subject of ex situ and in situ conservation projects in the regions botanical gardens. We recommend that preliminary conservation assessments be made of the 25 Data Deficient taxa so that conservation measures can be implemented for those facing imminent threats.

Sweet Drinks Are Made of This: Conservation Genetics of an Endemic Palm Species from the Dominican Republic

Pseudophoenix ekmanii is a threatened palm species endemic to the Dominican Republic. Sap from trees is extracted to make a local drink; once they are tapped the individual usually dies. Plants are also illegally harvested for the nursery trade and destroyed by poachers hunting the endemic and threatened Hispaniolan parrot. We used 7 DNA microsatellite markers to assist land managers in developing conservation strategies for this palm. We sampled 4 populations along the known distribution range of this species (3 populations from the mainland and 1 from the small island of Isla Beata), for a total sample of n = 104. We found strong evidence for genetic drift, inbreeding, and moderate gene flow (i.e., all populations had at least 4 loci that were not in Hardy-Weinberg equilibrium, at least 9 loci pairs were in linkage disequilibrium, the pairwise F(ST) values ranged from 0.069 to 0.266, and had positive F(IS) values). Data supported an isolation-by-distance model, and cluster analyses based on genetic distances resolved 2 groups that match a north-south split. The population from Isla Beata had the lowest levels of genetic diversity and was the only one in which we found pairs of individuals with identical shared multilocus genotypes.

Dransfieldia (Arecaceae)—A New Palm Genus from Western New Guinea

Abstract The systematic placement of the little-known species Ptychosperma micranthum (Arecaceae/Palmae: Arecoideae: Areceae) from far western New Guinea has been repeatedly disputed, resulting in recombinations in both Heterospathe and Rhopaloblaste. However, comparative morphological and molecular phylogenetic studies provide strong evidence against the placement of the species within any of these three genera, or indeed in any other accepted genus. Thus, a new genus, Dransfieldia, is herein described and a new combination, Dransfieldia micrantha, is made. Morphological character analyses demonstrate that the combination of character states that defines Dransfieldia is highly distinctive, despite the fact that many of the states are homoplasious. Dransfieldia micrantha is a slender, unarmed palm possessing a well-defined crownshaft, strongly ridged leaflets with entire, acute apices, an infrafoliar inflorescence with a persistent prophyll that is split apically by the exertion of the peduncular bract, a peduncle that is longer than the rachis, bullet-shaped multistaminate male flower buds in which the filaments in the outer whorl are irregularly inflexed in bud, and fruit with apical stigmatic remains. Molecular phylogenies strongly support the position of Dransfieldia within tribe Areceae, placing it within a clade of genera from the western Pacific.

A survey of cyanogenesis in palms (Arecaceae)

We surveyed leaf material of 545 individual palms representing 108 genera and 155 species for cyanogenesis using the Feigl-Anger test. We detected HCN production in only two species of one genus, Drymophloeus. Additional smaller surveys of shoot meristems and roots revealed cyanogenesis only in the shoot meristem of one species of Dypsis. Our results indicate that cyanogenesis is rather rare in the family. ( 2000 Elsevier Science Ltd. All rights reserved.

Phylogeny and Systematic Position of Feddea (Asteraceae: Feddeeae): a Taxonomically Enigmatic and Critically Endangered Genus Endemic to Cuba

Abstract Abstract—The systematic position of Feddea (Asteraceae) has been enigmatic ever since its publication in 1925. The latest taxonomic accounts of the family left it either unplaced within subfamily Asteroideae or unplaced within tribe Inuleae. Macro-morphological and electron microscopy data (scanning electron microscopy and transmission electron microscopy) indicated that Feddea is not part of an early branching lineage of the Asteraceae, contrary to what had been suggested in initial taxonomic accounts. Feddea has style branches with a 2-banded (vs. continuous) stigmatic surface, thus differing from early diverging lineages of the family. Among Asteroideae, Feddea is diagnosed by discoid capitula with all florets bisexual, long-caudate anthers, noncarbonized cypselae, and pollen with a narrow cavus region, columellae without internal foramina, but with a complex basal columellate layer. A phylogenetic reconstruction based on nucleotide sequences of the chloroplast gene ndhF showed that Feddea is sister to the Heliantheae s.l. There were, however, no clear morphological synapomorphies shared with that tribe and we therefore propose Feddeeae as a new unispecific tribe to accommodate this critically endangered genus restricted to Eastern Cuba.