Systematics of the Neotropical caddisfly genus Notidobiella Schmid (Trichoptera, Sericostomatidae), with the description of 3 new species

Three new species of Notidobiella Schmid (Insecta: Trichoptera) are described from South America: Notidobiella amazonianasp. n. (Brazil), Notidobiella brasilianasp. n. (Brazil), and Notidobiella ecuadorensissp. n. (Ecuador). In addition, the 3 previously described species in the genus, Notidobiella chacayana Schmid, Notidobiella inermis Flint, and Notidobiella parallelipipeda Schmid, all endemic to southern Chile, are redescribed and illustrated, including the females of each species for the first time, and a key to males of the species in the genus is provided. The occurrence of Notidobiella in Brazil and Ecuador represents a significant extension of the range of the genus beyond southern Chile where it previously was thought to be endemic. The biogeography of Sericostomatidae and other austral South American Trichoptera is reviewed. The presence of the family in South America may not be part of a "transantarctic" exchange, but instead may represent an earlier occurence in the region. The distribution of Notidobiella in tropical South America likely represents recent dispersal from southern South America to the north.     

The biogeography of Gunnera L.: vicariance and dispersal

Aim The genus Gunnera is distributed in South America, Africa and the Australasian region, a few species reaching Hawaii and southern Mexico in the North. A cladogram was used to (1) discuss the biogeography of Gunnera and (2) subsequently compare this biogeographical pattern with the geological history of continents and the patterns reported for other Southern Hemisphere organisms. Location Africa, northern South America, southern South America, Tasmania, New Zealand, New Guinea/Malaya, Hawaii, North America, Antarctica. Methods A phylogenetic analysis of twenty‐six species of Gunnera combining morphological characters and new as well as published sequences of the ITS region, rbcL and the rps16 intron, was used to interpret the biogeographical patterns in Gunnera. Vicariance was applied in the first place and dispersal was only assumed as a second best explanation. Results The Uruguayan/Brazilian Gunnera herteri Osten (subgenus Ostenigunnera Mattfeld) is sister to the rest of the genus, followed sequentially upwards by the African G. perpensa L. (subgenus Gunnera), in turn sister to all other, American and Australasian, species. These are divided into two clades, one containing American/Hawaiian species, the other containing all Australasian species. Within the Australasian clade, G. macrophylla Blume (subgenus Pseudogunnera Schindler), occurring in New Guinea and Malaya, is sister to a clade including the species from New Zealand and Tasmania (subgenus Milligania Schindler). The southern South American subgenus Misandra Schindler is sister to a clade containing the remaining American, as well as the Hawaiian species (subgenus Panke Schindler). Within subgenus Panke, G. mexicana Brandegee, the only North American species in the genus, is sister to a clade wherein the Hawaiian species are basal to all south and central American taxa. Main conclusions According to the cladogram, South America appears in two places, suggesting an historical explanation for northern South America to be separate from southern South America. Following a well‐known biogeographical pattern of vicariance, Africa is the sister area to the combined southern South America/Australasian clade. Within the Australasian clade, New Zealand is more closely related to New Guinea/Malaya than to southern South America, a pattern found in other plant cladograms, contradictory to some of the patterns supported by animal clades and by the geological hypothesis, respectively. The position of the Tasmanian G. cordifolia, nested within the New Zealand clade indicates dispersal of this species to Tasmania. The position of G. mexicana, the only North American species, as sister to the remaining species of subgenus Panke together with the subsequent sister relation between Hawaii and southern South America, may reflect a North American origin of Panke and a recolonization of South America from the north. This is in agreement with the early North American fossil record of Gunnera and the apparent young age of the South American clade.     

Phylogeny and diversification of Valerianaceae (Dipsacales) in the southern Andes

The southern Andean clade of Valeriana provides an excellent model for the study of biogeography. Here we provide new data to help clarify phylogenetic relationships among the South American valerians, with special focus on taxa found in the southern Andes. We found that the southern Andean taxa formed a clade in maximum likelihood and maximum parsimony analyses, and used a Bayesian relaxed clock method to estimate divergence times within Valerianaceae. Our temporal results were similar to other studies, but we found greater variance in our estimates, suggesting that the species of Valeriana have been on the South American continent for some time, and have been successful at exploiting new niche opportunities that reflects the contemporary radiation. Regardless of the time frame for the radiation of the clade, the uptick in the rate of diversification in Valerianaceae appears correlated with a dispersal event from Central to South America. The appearance of Valeriana in the southern Andes (13.7 Ma) corresponds with the transition from closed forest on the western side of the Andes in central Chile to a more open Mediterranean woodland environment. This would suggest that the high species richness of Valerianaceae in South America is the result of multiple, smaller radiations such as the one in the southern Andes, that may or may not be geographically isolated. These smaller radiations may also be driven by species moving into new biomes (migration from a temperate to a more Mediterranean-type climate and into alpine). The degree to which different ecological and geological factors interact to drive diversification is difficult to ascertain. Likewise, without a better-resolved phylogeny it is impossible to determine the directionality of dispersal in this group; did they colonize the southern Andes first, then move northward as the central Andean alpine habitat became more widely available or vice versa?     

Molecular phylogeny of the genus Philodendron (Araceae): delimitation and infrageneric classification

The genus Philodendron (Araceae) is a large neotropical group whose classification remains unclear. Previous classifications are based on morphological characters, mainly from the inflorescence, flower and leaf shape. The classification by Krause, with few modifications, is still the most commonly used system. To examine phylogenetic relationships in the genus, two ribosomal DNA nuclear markers, internal transcribed spacer (ITS) and external transcribed spacer (ETS), and the chloroplast intron rpl 16, were sequenced and analysed for more than 80 species of Philodendron and its close relative Homalomena . According to the resulting phylogeny, the genus Homalomena may be paraphyletic to the genus Philodendron . The inclusion of the American Homalomena species within the genus Philodendron might resolve this taxonomic problem. All three subgenera of Philodendron were revealed as monophyletic. Below the subgeneric level, the groups obtained in our phylogeny globally correspond to sections recognized in previous classifications. Among the morphological characters used by previous taxonomists to build their classifications, and which we optimized onto one of the most parsimonious trees, most characters were found to be homoplasious. However, leaf shape, characteristics of the sterile zone on the spadix and venation patterns are useful for delimiting subgenera and sections within the genus.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 13–27.     

NOTHOFAGUS AND PACIFIC BIOGEOGRAPHY

Abstract — Gondwanan biogeography, particularly the relationships between southern South America, New Zealand, Australia, New Guinea and New Caledonia, has been much studied. Nothofagus is often used as the "test taxon", and many papers have been directed at using Nothofagus to explain Gondwanan biogeography. Cladistic biogeographers, working on plant material, have generally failed to find congruence among taxa expected from the southern Pacific disjunctions. New morphological and molecular data on the phytogeny of Nothofagus have re-opened the issue, and we analysed these data to construct a new hypothesis of the biogeography of the genus. We assembled all plant taxa for which we could find reasonably robust phylogenetic hypotheses, and sought a parsimonious biogeographical pattern common to all. Two analyses, based on different assumptions, produced the same general areacladogram. We use the general area-cladogram, in conjunction with the fossil record of Nothofagus to construct a historical scenario for the evolution of the genus. This scenario indicates extensive extinction, but also suggests that Australia has a more recent relationship to New Zealand than to southern South America. This is not congruent with the current geological theories, nor with the patterns evident from insect biogeography. We suggest that concordant dispersal is an unlikely explanation for this pattern, and propose that the solution might be found in alternative geological hypotheses.     

Support for vicariant origins of the New Zealand Onychophora

Aim The distribution of Onychophora across the southern continents has long been considered the result of vicariance events. However, it has recently been hypothesized that New Zealand was completely inundated during the late Oligocene (25–22 Ma) and therefore that the entire biota is the result of long-distance dispersal. We tested this assumption using phylogenetic and molecular dating of DNA sequence data from Onychophora. Location New Zealand, Australia, South Africa, Chile (South America). Methods We obtained DNA sequence data from the nuclear genes 28S and 18S rRNA to reconstruct relationships among species of Peripatopsidae (Onychophora). We performed molecular dating under a Bayesian relaxed clock model with a range of prior distributions using the rifting of South America and South Africa as a calibration. Results Our phylogenetic trees revealed that the New Zealand genera Ooperipatellus and Peripatoides, together with selected Australian genera (Euperipatoides, Phallocephale and an undescribed genus from Tasmania), form a monophyletic group that is the sister group to genera from Chile (Metaperipatus) and South Africa (Peripatopsis and Opisthopatus). The relaxed clock dating analyses yielded mean divergence times from 71.3 to 78.9 Ma for the split of the New Zealand Peripatoides from their Australian sister taxa. The 0.95 Bayesian posterior intervals were very broad and ranged from 24.5 to 137.6 Ma depending on the prior assumptions. The mean divergence of the New Zealand species of Ooperipatellus from the Australian species Ooperipatellus insignis was estimated at between 39.9 and 46.2 Ma, with posterior intervals ranging from 9.5 to 91.6 Ma. Main conclusions The age of Peripatoides is consistent with long-term survival in New Zealand and implies that New Zealand was not completely submerged during the Oligocene. Ooperipatellus is less informative on the question of continuous land in the New Zealand region because we cannot exclude a post-Oligocene divergence. The great age of Peripatoides is consistent with a vicariant origin of this genus resulting from the rifting of New Zealand from the eastern margin of Gondwana and supports the assumptions of previous authors who considered the Onychophora to be a relict component of the New Zealand biota.     

Geographical diversification of the genus Cicer (Leguminosae: Papilionoideae) inferred from molecular phylogenetic analyses of chloroplast and nuclear DNA sequences

Cicer L. (Leguminosae: Papilionoideae) consists of 42 species of herbaceous or semi-shrubby annuals and perennials distributed throughout the temperate zones of the Northern Hemisphere. The origin and geographical relationships of the genus are poorly understood. We studied the geographical diversification and phylogenetic relationships of Cicer using DNA sequence data sampled from two plastid regions, trnK / matK and trnS - trnG , and two nuclear regions, the internal transcribed spacer (ITS) and external transcribed spacer (ETS) regions of nuclear ribosomal DNA, from 30 species. The results from the phylogenetic analyses of combined nuclear and chloroplast sequence data revealed four well-supported geographical groups: a Middle Eastern group, a West-Central Asian group, an Aegean–Mediterranean group, and an African group. Age estimates for Cicer based on methods that do not assume a molecular clock (for example, penalized likelihood) demonstrate that the genus has a Mediterranean origin with considerable diversification in the Miocene/Pliocene epochs. Geological events, such as mountain orogenesis and environmental changes, are major factors for the dispersal of Cicer species. The early divergence of African species and their geographically distinct region in the genus suggest a broader distribution pattern of the genus in the past than at present.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 154 , 175–186.     

First fossil Molinaranea Mello‐Leitão, 1940 (Araneae: Araneidae), from middle Miocene Dominican amber,with a phylogenetic and palaeobiogeographical analysis of the genus

The first fossil Molinaranea is described, from middle Miocene Dominican amber. This record extends the known range of the genus back 16 million years; it also extends the geographical range of the genus through time, with extant species known only from Chile, Argentina, the Falkland Islands, and Juan Fernandez Island. A parsimony‐based phylogenetic analysis was performed, which indicates that the fossil species, Molinaranea mitnickii sp. nov. , is nested with Molinaranea magellanica Walckenaer, 1847 and Molinaranea clymene Nicolet, 1849 . A modified Brooks parsimony analysis was conducted in order to examine the biogeography and origins of the fossil species in the Dominican Republic; the analysis suggests that M. mitnickii sp. nov. arrived in Hispaniola from South America as a result of a chance dispersal event. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 711–725.     

From East Gondwana to Central America: historical biogeography of the Alstroemeriaceae

Aim The Alstroemeriaceae is among 28 angiosperm families shared between South America, New Zealand and/or Australia; here, we examine the biogeography of Alstroemeriaceae to better understand the climatic and geological settings for its diversification in the Neotropics. We also compare Alstroemeriaceae with the four other Southern Hemisphere families that expanded from Patagonia to the equator, to infer what factors may have permitted such expansions across biomes. Location South America, Central America, Australia and New Zealand. Methods Three chloroplast genes, one mitochondrial gene and one nuclear DNA region were sequenced for 153 accessions representing 125 of the 200 species of Alstroemeriaceae from throughout the distribution range; 25 outgroup taxa were included to securely infer evolutionary directions and be able to use both ingroup and outgroup fossil constraints. A relaxed‐clock model relied on up to three fossil calibrations, and ancestral ranges were inferred using statistical dispersal–vicariance analysis (S‐DIVA). Southern Hemisphere disjunctions in the flowering plants were reviewed for key biological traits, divergence times, migration directions and habitats occupied. Results The obtained chronogram and ancestral area reconstruction imply that the most recent common ancestor of Colchicaceae and Alstroemeriaceae lived in the Late Cretaceous in southern South America/Australasia, the ancestral region of Alstroemeriaceae may have been South America/Antarctica, and a single New Zealand species is due to recent dispersal from South America. Chilean Alstroemeria diversified with the uplift of the Patagonian Andes c. 18 Ma, and a hummingbird‐pollinated clade (Bomarea) reached the northern Andes at 11–13 Ma. The South American Arid Diagonal (SAAD), a belt of arid vegetation caused by the onset of the Andean rain shadow 14–15 Ma, isolated a Brazilian clade of Alstroemeria from a basal Chilean/Argentinean grade. Main conclusions Only Alstroemeriaceae, Calceolariaceae, Cunoniaceae, Escalloniaceae and Proteaceae have expanded and diversified from Patagonia far into tropical latitudes. All migrated northwards along the Andes, but also reached south‐eastern Brazil, in most cases after the origin of the SAAD. Our results from Alstroemeria now suggest that the SAAD may have been a major ecological barrier in southern South America.     

Late Cenozoic diversification of the austral genus Lagenophora (Astereae,Asteraceae)

Lagenophora (Astereae, Asteraceae) has 14 species in New Zealand, Australia, Asia, southern South America, Gough Island and Tristan da Cunha. Phylogenetic relationships in Lagenophora were inferred using nuclear and plastid DNA regions. Reconstruction of spatio‐temporal evolution was estimated using parsimony, Bayesian inference and likelihood methods, a Bayesian relaxed molecular clock and ancestral area and habitat reconstructions. Our results support a narrow taxonomic concept of Lagenophora including only a core group of species with one clade diversifying in New Zealand and another in South America. The split between the New Zealand and South American Lagenophora dates from 11.2 Mya [6.1–17.4 95% highest posterior density (HPD)]. The inferred ancestral habitats were openings in beech forest and subalpine tussockland. The biogeographical analyses infer a complex ancestral area for Lagenophora involving New Zealand and southern South America. Thus, the estimated divergence times and biogeographical reconstructions provide circumstantial evidence that Antarctica may have served as a corridor for migration until the expansion of the continental ice during the late Cenozoic. The extant distribution of Lagenophora reflects a complex history that could also have involved direct long‐distance dispersal across southern oceans. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177 , 78–95.     

Phylogeny of Cyttaria inferred from nuclear and mitochondrial sequence and morphological data

Cyttaria species (Leotiomycetes, Cyttariales) are obligate, biotrophic associates of Nothofagus (Hamamelididae, Nothofagaceae), the southern beech. As such Cyttaria species are restricted to the southern hemisphere, inhabiting southern South America (Argentina and Chile) and southeastern Australasia (southeastern Australia including Tasmania, and New Zealand). The relationship of Cyttaria to other Leotiomycetes and the relationships among species of Cyttaria were investigated with newly generated sequences of partial nucSSU, nucLSU and mitSSU rRNA, as well as TEF1 sequence data and morphological data. Results found Cyttaria to be defined as a strongly supported clade. There is evidence for a close relationship between Cyttaria and these members of the Helotiales: Cordierites, certain Encoelia spp., Ionomidotis and to a lesser extent Chlorociboria. Order Cyttariales is supported by molecular data, as well as by the unique endostromatic apothecia, lack of chitin and highly specific habit of Cyttaria species. Twelve Cyttaria species are hypothesized, including all 11 currently accepted species plus an undescribed species that accommodates specimens known in New Zealand by the misapplied name C. gunnii, as revealed by molecular data. Thus the name C. gunnii sensu stricto is reserved for specimens occurring on N. cunninghamii in Australia, including Tasmania. Morphological data now support the continued recognition of C. septentrionalis as a species separate from C. gunnii. Three major clades are identified within Cyttaria: one in South America hosted by subgenus Nothofagus, another in South America hosted by subgenera Nothofagus and Lophozonia, and a third in South America and Australasia hosted by subgenus Lophozonia, thus producing a non-monophyletic grade of South American species and a monophyletic clade of Australasian species, including monophyletic Australian and New Zealand clades. Cyttaria species do not sort into clades according to their associations with subgenera Lophozonia and Nothofagus.     

Historical biogeography of Hexabathynella , a cosmopolitan genus of groundwater Syncarida (Crustacea, Bathynellacea, Parabathynellidae)

Hexabathynella is the only cosmopolitan genus of the order Bathynellacea (Crustacea). The known species number 18, found in Europe (9), Africa (1), South America (2), North America (3) and Australia and New Zealand (3). Phylogenetic analysis suggests that the least derived species are those from South America and the most derived those from the Iberian Peninsula, North America and Australia. The five species with the most plesiomorphic characters occur in salt or brackish water, which supports a marine origin for the genus. Phylogenetic and biogeographical analyses suggest that the distribution of the genus can be explained by dispersion and a double vicariant biogeographical model based on plate tectonics and the evolution of the Tethys during the Mesozoic and Cenozoic.  © 2003 The Linnean Society of London . Biological Journal of the Linnean Society , 2003, 78 , 457–466.     

Mitochondrial DNA phylogeny of the woodpecker genus Veniliornis (Picidae, Picinae) and related genera implies convergent evolution of plumage patterns

The woodpecker genus Veniliornis comprises 12 species, all restricted to the New World tropics. The seemingly distantly related genus Picoides is broadly distributed in Eurasia and North America with two putative species, P. lignarius and P. mixtus , occurring in South America. The two genera are clearly distinct with respect to general plumage colouration and patterning as well as habitat utilization and thus traditionally have been placed in different tribes. Phylogenetic analyses of mtDNA sequences from the COI and cyt b genes indicated that both genera are reciprocally paraphyletic. The two South American species of Picoides belong to a clade comprising most species of Veniliornis , but V. fumigatus of Central and north-western South America belongs to a clade comprising species of Picoides . The mtDNA tree also indicated that Veniliornis is not closely related to the genus Piculus, as is implicit in current classifications. Misclassifications involving Veniliornis at both the generic and tribal levels appear to result from convergent evolution of plumage traits in specific forest types. We infer that the common ancestor of Veniliornis entered South America approximately at the time the Isthmus of Panama was formed, and diversification within South America was rapid.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 611–624.     

Phylogenetic analysis of eastern Asian and eastern North American disjunct Lespedeza (Fabaceae) inferred from nuclear ribosomal ITS and plastid region sequences

Lespedeza (tribe Desmodieae, Fabaceae) follows a disjunct distribution in eastern Asia and eastern North America. Phylogenetic relationships among its species and related taxa were inferred from nuclear ribosomal internal transcribed spacer (ITS) and plastid sequences (trnH‐psbA, psbK‐psbI, trnK‐matK and rpoC1). We examined 35 species of Lespedeza, two of Kummerowia and one of Campylotropis, the sole constituents of the Lespedeza group. An analysis of these data revealed that the genus Campylotropis is sister to the other two genera. However, we were unable to resolve the relationships between Kummerowia and Lespedeza in the strict consensus trees of parsimony analyses based on plastid and combined DNA data. In the genus Lespedeza, the Old World subgenus Macrolespedeza is monophyletic, whereas the transcontinental subgenus Lespedeza is paraphyletic. Monophyly of eastern Asian species and of North American species is strongly supported. Although inconsistent with the traditional classification, this phylogenetic finding is consistent with seedling morphology. Three subgroups recognized in subgenus Macrolespedeza were unresolved in our phylogenetic trees. An incongruence length difference (ILD) test indicated that the two partitions (nuclear ITS and plastid sequences) were significantly incongruent, perhaps because of hybridization between species in Lespedeza. Most of the primary clades of tribe Desmodieae are Asian, implying that the relatively few New World ones, such as those in Lespedeza, are more recently derived from Asia. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 221–235.     

Panbiogeography of Nothofagus (Nothofagaceae): analysis of the main species massings

Aim The aim of this paper is to analyse the biogeography of Nothofagus and its subgenera in the light of molecular phylogenies and revisions of fossil taxa. Location Cooler parts of the South Pacific: Australia, Tasmania, New Zealand, montane New Guinea and New Caledonia, and southern South America. Methods Panbiogeographical analysis is used. This involves comparative study of the geographic distributions of the Nothofagus taxa and other organisms in the region, and correlation of the main patterns with historical geology. Results The four subgenera of Nothofagus have their main massings of extant species in the same localities as the main massings of all (fossil plus extant) species. These main massings are vicariant, with subgen. Lophozonia most diverse in southern South America (north of Chiloé I.), subgen. Fuscospora in New Zealand, subgen. Nothofagus in southern South America (south of Valdivia), and subgen. Brassospora in New Guinea and New Caledonia. The main massings of subgen. Brassospora and of the clade subgen. Brassospora/subgen. Nothofagus (New Guinea–New Caledonia–southern South America) conform to standard biogeographical patterns. Main conclusions The vicariant main massings of the four subgenera are compatible with largely allopatric differentiation and no substantial dispersal since at least the Upper Cretaceous (Upper Campanian), by which time the fossil record shows that the four subgenera had evolved. The New Guinea–New Caledonia distribution of subgenus Brassospora is equivalent to its total main massing through geological time and is explained by different respective relationships of different component terranes of the two countries. Global vicariance at family level suggests that Nothofagaceae/Nothofagus evolved largely as the South Pacific/Antarctic vicariant in the breakup of a world‐wide Fagales ancestor.     

When phylogenetics met biogeography: Willi Hennig,Lars Brundin and the roots of phylogenetic and cladistic biogeography

Willi Hennig's (Beitr. Ent. 1960, 10, 15) Die Dipteren-Fauna von Neuseeland als systematisches und tiergeographisches Problem applied a phylogenetic approach to examine the distributional patterns exhibited by the Diptera of New Zealand. Hennig showed how phylogenetic trees may be used to infer dispersal, based on the progression and deviation rules, and also discussed the existence of vicariance patterns. The most important author who applied Hennig's phylogenetic biogeography was Lars Brundin, when analysing the phylogenetic relationships of two taxa of Chironomidae (Diptera) and using them to examine the biogeographic relationships of Australia, New Zealand, South America and South Africa. The relevance of Brundin's contribution was noted by several authors, as it began the cladistic or vicariance approach to biogeography, that implies the discovery of vicariance events shared by different monophyletic groups. Both phylogenetic and cladistic biogeography have a place in contemporary biogeography, the former for analysing taxon biogeography and the latter when addressing Earth or biota biogeography. The recent use of the term “phylogenetic biogeography” to refer to a posteriori methods of cladistic biogeography is erroneous and should be avoided.     

Evolution of St Helena arborescent Astereae (Asteraceae): relationships of the genera Commidendrum and Melanodendron

The cladistic relationships of endemic Commidendrum (four species) and Melanodendron (one species) from St Helena were inferred from sequences of ITS1 and ITS2 of nuclear ribosomal DNA. Despite showing a range of morphological and ecological variation, the four species of Commidendrum , C. spurium , C. robustum , C. rotundifolium , and C. rugosum , form a closely related monophyletic group with percentage sequence divergence between 0.2 and 0.9%. Melanodendron integrifolium is sister to Commidendrum indicating that the two genera may have evolved from a common ancestor that arrived in St Helena via a single dispersal event. The closest relatives of Commidendrum and Melanodendron appear to be South African, in the predominantly shrubby genus Felicia , although further sampling of South African Astereae is required. We discuss the evolution and adaptive radiation of these rare and threatened species with particular reference to the possible role of heterochrony.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 69–83.     

East meets west: biogeology of the Campbell Plateau

The New Zealand Subantarctic Islands, emergent remnants of the Campbell Plateau, were given World Heritage status in 1998 in recognition of their importance to global biodiversity. We describe the flora and fauna of these islands and discuss the results of recent phylogenetic analyses. Part of the New Zealand Subantarctic biota appears to be relictual and to be derived from west Gondwana. The relictual element is characterized by genera endemic to the Campbell Plateau that show relationships with taxa of the southern South Island, New Zealand, southern South America, and the north Pacific. In contrast, a younger, east Gondwanan element is composed of species that are either taxonomically identical to widespread mainland species, or endemic species with close New Zealand relatives. Area cladograms support the inclusion of the southern South Island, New Zealand and Macquarie Island (although this is separate geologically) as parts of the Campbell Plateau, but suggest the Chatham Rise and Torlesse terranes of the eastern South Island, New Zealand were originally parts of east Gondwana. East and west Antarctica acted as independent plates during the breakup of Gondwana, and were separated by oceanic crust until a compressive phase sutured them along the trace of the trans‐Antarctic mountains during the early Tertiary. The Campbell Plateau microcontinent was connected to west Antarctica until its separation at 80 Mya, contemporaneous with the separation of the southern portion of the Melanesian rift from east Gondwana. Presently the Campbell Plateau is joined to the Melanesian Rift along the Alpine Fault. Cenozoic plate tectonic reconstructions place the Campbell Plateau adjacent to the Melanesian Rift throughout the rift–drift phase, relative motion being confined to strike–slip movement over the last 20 Myr. Our synthesis of phylogenetic and plate tectonic evidence suggests that the Alpine Fault is the most recent development of a much older extensional rift/basin boundary originally separating west and east Gondwana. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86 , 95–115.     

Species diversity and endemism in the Daphnia of Argentina: a genetic investigation

Although the temperate regions of South America are known to have a diverse daphniid fauna, there has been no genetic evaluation of the existing taxonomic system or of the affinities between the North and South American faunas. The present study analyses mitochondrial DNA sequences and allozyme variation to investigate species diversity in 176 Daphnia populations from Argentina. This work established the presence of at least 15 species in Argentina, six of which are either undescribed or are currently misidentified and two of which represent range extensions of North American taxa. Eleven of the Argentine species appear endemic to South America, while the remaining four also occur in North America. In the latter cases, the close genetic similarity between populations from North and South America indicates the recent exchange of propagules between the continents. While biological interactions and habitat availability have undoubtedly contributed to the observed species distributions, chance dispersal has apparently played a dominant role in structuring large-scale biogeographical patterns in this genus and probably in other passively-dispersed organisms.  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 140 , 171−205.