This dissertation presents a comprehensive study on the origin and evolutionary relationships of the species of Bursera in Cuba, Hispaniola, Jamaica and the Bahamas. The goals of the first chapter were to test monophyly of the group, revisit a recent transfer of two species of Bursera to Commiphora, and place recently discovered mainland species using the reconstructed phylogenies. Additionally, divergence estimations using fossils were used as independent tests of several hypotheses regarding the arrival of the modern biota to the Greater Antilles and Bahamas (GAB). I conclude that all endemic taxonomic entities of the genus in this region belong to Bursera subgen. Bursera but that two separate lineages colonized the GAB via dispersal. The genus diversified during the Middle Miocene to Pliocene, and the data corroborate several paleogeographic events during that interval. The second chapter presents informative characters from leaf anatomy and leaf architecture for the 14 endemic species of Bursera distributed in the GAB. There is evidence for some evolutionary tendencies in the group, among them a trend toward small, simple, amphistomatic and unifacial leaves, character states for which ecological correlates can now be studied. Morphological and anatomical evidence corroborates phylogenetic results in suggesting that a population of B. glauca in Cuba is a new species. Finally, the third chapter constitutes the first taxonomic account and description of all known endemic species of Bursera in the region and reflects the results of the previous chapters. The primary results are as follows: (1) a new species from eastern Cuba, B. yaterensis, is described; (2) five species of Commiphora are returned to Bursera; (3) B. nashii is treated as conspecific with B. glauca; and (4) B. ovata is treated as conspecific with B. trinitensis. A dichotomous key is provided using mostly vegetative characters due to the frequent lack of adequate reproductive material and the relative uniformity of most floral and fruit characters. Each species description includes leaf architecture (morphology and venation pattern) and anatomy, introducing characters that could and should be used for describing and distinguishing other Bursera in Meso- and South America as well as for African Commiphora.

Die antillanische Flora ist eine der artenreichsten der Erde. Trotz jahrhundertelanger floristischer Forschung zeigen jüngere Studien, daß der Archipel noch immer weiße Flecken beherbergt. Das trifft besonders auf die Familie der Orchideen zu, deren letzte Bearbeitung für Cuba mehr als ein halbes Jahrhundert zurückliegt. Die vorliegende Arbeit basiert auf der lang ausstehenden Revision der Orchideengattung Pleurothallis R. Br. für die Flora de Cuba. Mittels weiterer morphologischer, palynologischer, molekulargenetischer, phytogeographischer und ökologischer Untersuchungen auch eines Florenteils der anderen Großen Antillen wird die Genese der großantillanischen Pleurothallis-Flora rekonstruiert. Der Archipel umfaßt mehr als 70 Arten dieser Gattung, wobei die Zahlen auf den einzelnen Inseln sehr verschieden sind: Cuba besitzt 39, Jamaica 23, Hispaniola 40 und Puerto Rico 11 Spezies. Das Zentrum der Diversität liegt im montanen Dreieck Ost-Cuba - Jamaica - Hispaniola, einer Region, die 95 % der groß-antillanischen Arten beherbergt, wovon 75% endemisch auf einer der Inseln sind. Da die meisten Arten entweder endemisch oder pankaribisch verbreitet sind, bleiben die floristischen Bezüge zwischen den Inseln und zu den kontinentalen Nachbargebieten nur schwach ausgeprägt. Immerhin lassen sich einige Verbindungen unter den Inseln der Großen Antillen und besonders zu Mittelamerika erkennen. Diese Affinitäten steigen von Ost nach West. Molekulargenetische und (mikro-)morphologische Daten zeigen ein deutliches Muster der historischen Biogeographie. Danach lassen sich die antillanischen Arten hinsichtlich ihrer Genese in drei Gruppen einteilen. 25% der Arten sind pankaribisch verbreitet, wobei der Großteil der Inselpopulationen vom mittelamerikanischen Festland stammt. Ebenfalls aus dieser Region stammen weitere 25%, die jedoch auf den Inseln neue Arten gebildet haben. Die verbleibenden 50% der groß-antillanischen Sippen sind autochthon und das Ergebnis adaptiver Radiation auf den Inseln. Diese intensive Kladogenese beschränkt sich auf drei Verwandtschaftskreise innerhalb der Gattung Pleurothallis in den Untergattungen Antilla Luer und Specklinia Lindl. (2 Linien). Es stellte sich heraus, daß der überwiegende Anteil der Artbildungsprozesse allopatrischer Natur ist. Sympatrie konnte nur in einem einzigen Fall direkt belegt werden. Das Ergebnis der allopatrischen Speziation sind zwei Typen von Vikarianz, räumlich geographischer und geologischer. In Cuba sind überraschenderweise fast 80% der endemischen Arten an einen Gesteinstyp gebunden, überwiegend an Serpentin. West-Hispaniola, wo viele Schwesternarten cubanischer Sippen beheimatet sind, besteht fast ausschließlich aus Kalkstein. Geographische Vikarianz ist daher oft geologisch unterlegt, eine Bindung die für Epiphyten kaum vermutet wurde. Hinter der Geologie verbergen sich jedoch eher Bestäuberareale und weniger physiologische Anpassung als limitierender Faktor. Eine Verfrachtung in Vegetation auf anderem petrologischen Untergrund scheint damit der Hauptauslöser für Artbildungen gewesen zu sein. Ausgangspunkt waren höchstwahrscheinlich individuenarme Gründerpopulationen die den Bedingungen eines founder events ausgesetzt waren. Neben den reichen geologischen Verhältnissen im Dreieck Ost-Cuba - Jamaica - Hispaniola wird die intensive Artbildung durch weitere spezifisch lokale Bedingungen unterstützt. Karibische Wirbelstürme dürften entlang der Hauptrouten für eine häufige Verfrachtung von Samen oder Pflanzen von Mittelamerika auf die Großen Antillen sowie zwischen den Inseln selber verantwortlich sein. Ein zweiter günstiger Umstand für erfolgreiche Migration innerhalb des Dreiecks besteht in der räumlichen Nähe der Inselgebirge und deren optimalen klimatischen Bedingungen für die Besiedlung durch mikrophytische Epiphyten. Molekulargenetische Daten lieferten weiterhin wertvolle Informationen in Bezug auf die beiden aktuell diskutierten Systeme der Pleurothallidinae, einer streng morphologischen (Luer) und einer fast ausschließlich auf DNA-Sequenzen (Pridgeon & Chase) basierenden Klassifikation. DNA-Sequenzen der cubanischen Arten stützen das neue System von Pridgeon & Chase weitestgehend, zeigen aber Widersprüche bezüglich der Monophylie in einigen der neuen oder wieder errichteten Taxa. Angesicht dessen, daß die karibische Florenregion leider nicht nur durch ihre Biodiversität zu den zehn globalen hot spots zählt, sondern auch durch die großflächige Zerstörung von Primärvegetation, war es auch ein Anliegen der vorliegenden Arbeit, ein erstes detailliertes Bild von Genese und Verbreitung antillanischer Orchideen zu vermitteln. Diese Daten können direkt für die Gestaltung und das Management von karibischen Schutzgebieten eingesetzt werden, da Orchideen in der Naturschutzpolitik einen hohen Argumentationswert besitzen. / The Antillean Flora is one of the most diverse on our globe. However, despite floristic work for centuries recent studies show that there are still blank areas. This is especially the case in the family Orchidaceae, which, in the case of the Cuban Flora, has been reviewed more than half a century ago for the last time. The work presented here is based on the long pending revision of the genus Pleurothallis R. Br. for the Flora de Cuba. Adding further morphological, palynological, molecular, and ecological data this study is aimed at the reconstruction of the Greater Antillean Pleurothallis flora. The archipelago comprises more than 70 species of this genus, with a differing diversity on the particular islands; Cuba accommodates 39 taxa, Jamaica 23, Hispaniola 40 and Puerto Rico 11. The centre of diversity lies within the triangle E Cuba - Jamaica - W Hispaniola, a region that accommodates about 95% of the Greater Antillean species. 75% of the taxa are confined to just one island. Since most of the plants are either endemic or are of pan-Caribbean distribution floristic relationships among the islands and with regard to neighbouring continental areas remain rather indistinct. The strongest affinities are with Central America. Floristic relationships with that area increase from E towards W. Molecular and (micro-)morphological data show a clear pattern of historical phytogeography. Concerning their origin there are 3 groups of species. 25% of the Greater Antillean taxa are widespread in the Pan-Caribbean area, with the majority of the island populations having their origin presumably on the Central American continent. Another 25% are derived from Central American ancestors too, however, they have evolved into new species on the islands in the course of migration. The remaining 50% of the Greater Antillean taxa are autochthonous. They are the result of adaptive radiation on the archipelago. Intense cladogenesis is confined to 3 lineages within Pleurothallis. They belong to the subgenera Antilla Luer and Specklinia Lindl. (2 lineages). The majority of speciation events shows an allopatric pattern. Sympatry during speciation could be detected in a single case only. Allopatric speciation has resulted into 2 types of vicariance, spatial geographic and geological. Indeed, 80% of the Cuban endemics are associated with a single type of rock, serpentine in most cases. In contrast, W Hispanola where many sister taxa of Cuban pleurothallids live, is formed almost exclusively by limestone. In many cases, geographic vicariance is therefore geologically defined, a surprising association in epiphytic orchids. Geological vicariance, in turn, may have been brought about by pollinator distribution rather than by physiological adaptation to the geological environment. Migration to petrologically different localities seems to be the main trigger for speciation in Cuban Pleurothallis. This process was most probably started with a small number of individuals that met conditions of a founder event. Apart from the geologically rich background in the triangle E Cuba - Jamaica - Hispaniola there are other specific local conditions that are responsible for the rich diversity. Caribbean hurricanes provide a powerful means of transport along their main routes. They should be responsible for frequent migrations from the Central American mainland to the archipelago and between the islands. Moreover, the mountains within the triangle are in close spatial neighbourhood and meet favourable climatic conditions for the colonisation of small epiphytes. Molecular data from the Cuban species of Pleurothallis yielded valuable information for the current discussion concerning the morphological (Luer) and molecular classifications (Pridgeon & Chase) of the subtribe. These data support the new molecular based system to a great extent, however, they show new inconsistencies with respect to monophyly in some of the new or resurrected taxa. Considering that the Caribbean Flora belongs to the ten global hot spots, due to its diversity on the one and the loss of primal vegetation on the other side, it was a goal of the present thesis to impart a detailed picture of the genesis and distribution of Antillean orchids. Bearing in mind the political value of orchids in conservation these data can be used directly for the organisation and management of Caribbean nature reserves.

I focus on phylogenetic relationships of teiid lizards beginning with generic and species relationship within the family, followed by a detailed biogeographical examination of the Caribbean genus Pholidoscelis, and end by studying species boundaries and phylogeographic patterns of the widespread Giant Ameiva Ameiva ameiva. Genomic data (488,656 bp of aligned nuclear DNA) recovered a well-supported phylogeny for Teiidae, showing monophyly for 18 genera including those recently described using morphology and smaller molecular datasets. All three methods of phylogenetic estimation (two species tree, one concatenation) recovered identical topologies except for some relationships within the subfamily Tupinambinae (i.e. position of Salvator and Dracaena) and species relationships within Pholidoscelis, but these were unsupported in all analyses. Phylogenetic reconstruction focused on Caribbean Pholidoscelis recovered novel relationships not reported in previous studies that were based on significantly smaller datasets. Using fossil data, I improve upon divergence time estimates and hypotheses for the biogeographic history of the genus. It is proposed that Pholidoscelis colonized the Caribbean islands through the Lesser Antilles based on biogeographic analysis, the directionality of ocean currents, and evidence that most Caribbean taxa originally colonized from South America. Genetic relationships among populations within the Ameiva ameiva species complex have been poorly understood as a result of its continental-scale distribution and an absence of molecular data for the group. Mitochondrial ND2 data for 357 samples from 233 localities show that A. ameiva may consist of up to six species, with pairwise genetic distances among these six groups ranging from 4.7–12.8%. An examination of morphological characters supports the molecular findings with prediction accuracy of the six clades reaching 72.5% using the seven most diagnostic predictors.

Nickel silicate laterite deposits developed on ultra-mafic rocks are similar in many general respects but they vary considerably in detail. The mineralogy of these surficial deposits is very complex and difficult to determine because of the fine grained nature and solid solution characteristics of the hydrous secondary minerals and because many of the phases are actually mineraloids that are poorly ordered or amorphous. To try some new approaches toward clarification of these phases, 24 samples from New Caledonia and Puerto Rico ranging from the ophiolite-ultramafic olivine-pyroxene-chromite-serpentine substrate rocks upward through intermediate phases of weathering to the final oxide -hydroxide iron cap phase were analyzed with the infrared spectrophotometer (IR -10) and with the automated X –ray diffractometer. Four limonite samples were also mineralogically analyzed. Goethite, secondary quartz, cryptomelane, hematite, chromite, talc, thuringite, and garnierite have been identified in various samples as weathering profile products.