Susan K. Pell

To move or to evolve: contrasting patterns of intercontinental connectivity and climatic niche evolution in 'Terebinthaceae' (Anacardiaceae and Burseraceae)

Many angiosperm families are distributed pantropically, yet for any given continent little is known about which lineages are ancient residents or recent arrivals. Here we use a comprehensive sampling of the pantropical sister pair Anacardiaceae and Burseraceae to assess the relative importance of continental vicariance, long-distance dispersal and niche-conservatism in generating its distinctive pattern of diversity over time. Each family has approximately the same number of species and identical stem age, yet Anacardiaceae display a broader range of fruit morphologies and dispersal strategies and include species that can withstand freezing temperatures, whereas Burseraceae do not. We found that nuclear and chloroplast data yielded a highly supported phylogenetic reconstruction that supports current taxonomic concepts and time-calibrated biogeographic reconstructions that are broadly congruent with the fossil record. We conclude that the most recent common ancestor of these families was widespread and likely distributed in the Northern Hemisphere during the Cretaceous and that vicariance between Eastern and Western Hemispheres coincided with the initial divergence of the families. The tempo of diversification of the families is strikingly different. Anacardiaceae steadily accumulated lineages starting in the Late Cretaceous–Paleocene while the majority of Burseraceae diversification occurred in the Miocene. Multiple dispersal- and vicariance-based intercontinental colonization events are inferred for both families throughout the past 100 million years. However, Anacardiaceae have shifted climatic niches frequently during this time, while Burseraceae have experienced very few shifts between dry and wet climates and only in the tropics. Thus, we conclude that both Anacardiaceae and Burseraceae move easily but that Anacardiaceae have adapted more often, either due to more varied selective pressures or greater intrinsic lability.

Poupartiopsis gen. nov. and its Context in Anacardiaceae Classification

Abstract Poupartiopsis spondiocarpus, a modest-sized tree of littoral forests of eastern Madagascar, is recognized as a distinct genus and described. Emended descriptions and circumscriptions of the recognized subfamilies Spondioideae and Anacardioideae are provided, as are separate keys to the genera of Spondioideae based on flowering and fruiting material and a table of diagnostic characters for distinguishing the genera. Molecular phylogenetic analysis and structural data including leaf architecture, floral morphology, and endocarp structure place Poupartiopsis in the Spondioideae, one of two subfamilies in Anacardiaceae.

Molecular phylogenetics and molecular clock dating of Sapindales based on plastid rbcL, atpB and trnL-trnF DNA sequences

This study focuses on reconstructing the time-calibrated phylogeny of the nine families comprising the order Sapindales, representing a diverse and economically important group of eudicots including citrus, mahogany, tree-of-heaven, cashew, mango, pistachio, frankincense, myrrh, lychee, rambutan, maple, and buckeye. We sampled three molecular markers, plastid genes rbcL and atpB, and the trnL-trnLF spacer region, and covered one-third of the generic diversity of Sapindales. All three markers produced congruent phylogenies using maximum likelihood and Bayesian methods for a set of taxa that included outgroups, i.e., members of the closely related orders Brassicales and Malvales, and the more distantly related Crossosomatales, Ranunculales, and Ceratophyllales. All results confirmed the current delimitation of the families within Sapindales, and the monophyly of the order. Concerning inter-familial relationships, Biebersteiniaceae and Nitrariaceae formed a basal grade (or sister clade) to the rest of Sapindales with moderate support. The sister relationship of Kirkiaceae to Anacardiaceae and Burseraceae was strongly supported. The clade combining Anacardiaceae and Burseraceae as well as the clade combining Meliaceae, Simaroubaceae, and Rutaceae each received strong support. The sister relationship between Meliaceae and Simaroubaceae was moderately supported. The position of Sapindaceae could not be resolved with confidence. The Sapindales separated from their sister clade, comprising Brassicales and Malvales, in the Early Cretaceous at ca. 112 Ma, and diversified into the nine families from ca. 105 Ma until ca. 87 Ma during Early to Late Cretaceous times. Biebersteiniaceae and Nitrariaceae have the longest stem lineages observed in Sapindales, possibly indicating that extinction may have had a greater role in shaping their extant diversity than elsewhere within the order. Divergence within the larger families (Anacardiaceae, Burseraceae, Meliaceae, Rutaceae, Sapindaceae, Simaroubaceae) started during the Late Cretaceous, extending into the Paleogene and Neogene.

Phylogenetic Split of Malagasy and African Taxa of Protorhus and Rhus (Anacardiaceae) Based on cpDNA trnL–trnF and nrDNA ETS and ITS Sequence Data

Abstract The African-Malagasy genus Protorhus and the African-Malagasy species of Rhus s.l. have been suggested to be polyphyletic, but definitive evidence has been lacking. We investigated a clade of Anacardiaceae subfamily Anacardioideae in order to clarify evolutionary relationships of the African-Malagasy members of these two genera. Phylogenetic analysis of sequence data from cpDNA trnL–trnF, and nrDNA ETS and ITS provide strong statistical support for the 1) polyphyly of Protorhus; 2) monophyly of Malagasy Protorhus species; 3) polyphyly of Rhus section Baronia (Malagasy Rhus). These results support the need for new circumscriptions of these groups. Two new combinations are proposed, Searsia erosa and Searsia pendulina.

A new species of Comocladia (Anacardiaceae) from Belize and Guatemala

Comocladia mayana, a new species of Anacardiaceae, is described, mapped and illustrated. The species is endemic to western Belize and adjacent Guatemala and is restricted to semi-deciduous moist forest on karstic limestone formations. It differs from all other Comocladia species by the combination of entire to subentire, acuminate leaflets and tetramerous staminate flowers.ResumenComocladia mayana, una especie nueva de Anacardiaceae, se describe, mapea e ilustra. La especie es endémica al oeste de Belice y Guatemala y se limita a bosque húmedo semi-deciduo sobre formaciones de piedra caliza cárstica. Se diferencia de otras especies de Comocladia por la combinación de foliolos enteros a subenteros y, acuminados, y flores estaminadas tetrámeras.

Phylogeny of Schinus L. (Anacardiaceae) with a new infrageneric classification and insights into evolution of spinescence and floral traits

Schinus, best known by its few cultivated and invasive species, is the largest genus of Anacardiaceae in southern South America. It is remarkably diverse compared to closely related genera, with approximately 42 species, most of which occur in several arid vegetation types and extend into Andean and Atlantic moist forests. The most comprehensive taxonomic revision of the genus dates to 1957, recognizing S. subg. Schinus and S. subg. Duvaua, the latter of which were further divided into two sections. Subsequent studies have highlighted morphological inconsistencies in this infrageneric classification, and species delimitation remains a challenge. Schinus has been poorly sampled in previous phylogenetic studies of Anacardiaceae, and thus any assumptions about its monophyly and relationships remain untested. We investigated the phylogenetic relationships of 44 Schinus taxa and sampled 122 specimens, including the outgroup, using nine nuclear and two plastid DNA sequence regions, most of them developed recently for Commiphora (Burseraceae, sister to Anacardiaceae). We used maximum parsimony, maximum likelihood, and Bayesian inference to infer relationships among species. We also constructed a morphological dataset, including vegetative anatomical features, and compared these characters to hypotheses based on molecular evidence in order to achieve a better understanding of the relationships among the species of Schinus and to related genera, aiming also to identify morphological characters and putative synapomorphies for major clades, and to discuss hypotheses regarding the evolution of structural traits in the genus. Our analyses strongly support the monophyly of Schinus, but also indicate that S. subg. Schinus and the sections of S. subg. Duvaua are polyphyletic. The phylogenetic relationships that emerged from our analyses include eight relatively well-supported lineages, but relationships among closely related species remain unclear in some clades. Ancestral state reconstructions demonstrate that several morphological and leaf-anatomical characters are valuable in characterizing some lineages. By contrast, most of the traits that have traditionally been used to circumscribe groups in Schinus show high levels of homoplasy. In light of these results, we present a novel sectional classification of Schinus based on a combination of character states associated with geographic distribution, corresponding to lineages that are mostly allopatric or at least ecologically distinct.

Fruit Morphology and Anatomy of the Spondioid Anacardiaceae

The Spondioideae subfamily of the Anacardiaceae is widely distributed today in tropical regions. Recent molecular phylogenetic investigations indicate that the Spondioideae are not monophyletic, but rather comprise at least two separate clades that are difficult to distinguish using vegetative and floral characters. Nevertheless, the syndrome of fruit characters traditionally used in identifying the subfamily is useful in discriminating genera of these clades and for identification of both modern and fossil anacardiaceous fruits. Here we document the morphology and anatomy of endocarps for representatives of all extant genera traditionally treated as Spondioideae, plus two genera that have been placed close to them in molecular investigations, Buchanania and Campnosperma. All genera are characterized by drupe-like fruits with sclerified stones that vary from uni- to multilocular depending on the genus. Germination modes vary throughout the Spondioideae. Some have characteristic plug-like opercula; others have recessed bilabiate germination valves, and still others open by apical flaps or simple slits. Although most currently recognized genera appear to be monophyletic, fruit morphology indicates that current circumscriptions of Cyrtocarpa, Poupartia and Tapirira are in need of revision.

Euleria (Anacardiaceae) is Picrasma (Simaroubaceae): The genus Picrasma in Cuba

The monotypic Cuban endemic genus Euleria (Anacardiaceae) is shown to be a species of Picrasma and the new combination, Picrasma tetramera, is made. Also, a misapplication of the name Picrasma cubensis is corrected. Complete descriptions and illustrations are presented for both P. tetramera and P. cubensis, as is a key to the Cuban genera of Simaroubaceae and species of Picrasma.ResumenSe demuestra que el género monotípico y endémico cubano, Euleria (Anacardiaceae), es en realidad una especie de Picrasma (Simaroubaceae). Adicionalmente, una nueva combinación, Picrasma tetramera, es presentada y la errónea aplicación del nombre Picrasma cubensis es discutida. Descripciones completas con ilustraciones son presentadas para Picrasma tetramera y Picrasma cubensis, junto con una clave para los géneros cubanos de Simaroubaceae y para las especies cubanas de Picrasma.