Disjunct Distribution Pattern Research Articles

Examples of disjunct distributions between Mediterranean and southern or eastern Africa in Meloidae (Coleoptera, Tenebrionoidea)

Biogeographia vol. XX/X - 2008 (Pubb/icato i/ 30 dicembre 2008) The Mediterranean—southern African disjunct distribution pattern Examples of disjunct distributions between Mediterranean and southern or eastern Africa in Meloidae (Coleoptera, Tenebrionoidea) MARCO A. BOLOGNA, ANDREA DI GIULIO, MONICA PITZALIS Dz'przrz‘iZ772e72t0 di Bio/ogirz /lm[7z'em‘zzle, Urziz/ersitiz degli Studi “Roma Tre”, 1/izzle Mrzrconi, 446, [~00]-46R0mzz e—mrzi[: [70[ogmz@zmz'r0mrz3. it Key words: Disjunct distribution, blister beetles, Mediterranean, southern Africa, eastern Africa SUMMARY In this paper some cases of distribution in Coleoptera Meloidae, possibly referable to the distributional “Mediterranean-southern African disjunct modelq, are examined and discussed. At least Four genera, two belonging to the subfamily Meloinae, tribe Mylabrini (Actcizor/in Laporte de Castelnau, 1840 and Cemcri: Marseul, 1870), and two to the subfamily Nemognathinae, tribe Nemognathini (Simri: Latreille, 1802 and Srmarizz Mulsant, 1857), have ranges which include both the Mediterranean—Sal1aran area and eastern and southern Africa. Other examples. briefly examined, concern taxa ofMeloinae or Nemognathinae which are primarily Mediterranean or Saharan, with isolated subranges also in the eastern Africa. Two main considerations seem evident from this analysis: 1) a distributional disjunct model with only Mediterranean and South African related species does not exist among Meloidae, but at most genera which have the greatest diversity in these two areas and relict species in eastern Africa; 2) the type of disjuncr distribution observed in some genera oFMeloidae seems referable to convergent biogeographical phenomena more than a late, single vicariance event. INTRODUCTION Meloidae is a family of Coleoptera Tenebrionoidea including about 3,000 species, belonging to approximately 130 genera (Bologna, 1991; Pinto and Bologna, 1999; Bologna and Pinto, 2001; Bologna, unpubl.). The biological and pharmacological literature widely treated these beetles, respectively because of their hypermetabolic larval development, which includes parasitic habits, and their production of cantharidin, a natural terpenoid used in the popular phar- macy, particularly as aphrodisiac (see Bologna, 1991 for a review of both aspects). The taxonomy of Meloidae genera and their distribution were recently reviewed by Pinto and Bologna (1999) and by Bologna and Pinto (2001) as concerns the New World and the Old World respectively. The Australasian

Molecular biogeography of Mediterranean and southern African disjunctions as exemplified by pollen beetles of the Meligethes planiusculus species-group and related taxa (Coleoptera: Nitidulidae; Meligethinae)

Biogeographia vol. XX/X - 2008 (Pubb/icato il 30 dice-mbre 2008) The Mediterranean—southern African disjunct distribution pattern Molecular biogeography of Mediterranean and southern African disjunctions as exemplified by pollen beetles of the Melzgetbesplnniusculus species—group and related taxa (Coleoptera: Nitidulidae; Meligethinae) PAOLO AUDISIO, ALESSIO DE BIASE, ASHLEY H. KIRK-SPRlGGS*, ANDREW R. CLINE**, MARCO TRIZZINO, GLORIA ANTONINI, EMILIANO MAN CINI D1jgczr'ti772e72to di Bio/ogizz Animzz/e e r2'elZ’U0mo, Szzpierzzzz Urziz/ersitfz dz’ Rama, z/izz A. Bore!/z’ 50, [-0016] Rome, Italy *De]gzzrtmem‘ of Entomology, Nzztiomzl MZl5€Zl77Z, Bl0emfi77zZ'ei7Z, 9300 South Afiicrz *”‘P[zzm‘ Pest Diagnostic: Center, Czzlzfbmirz Depamvzerzt of Food fl7ZdAgTiCZt[tZl7€, 3294 Men:/ow:/iew Road, Szzcranzerzto, CA 95832-1448, USA Key words: Mcliger/Jet, biogeography, disjunctions, dispersal, cytochrome oxidase I SUMMARY We investigated the apparent disjunction expressed in two related assemblages of species of the genus Me/{get/Jar, i.e. M. fiwrico/zz and its allies in the Cape region of South Africa and the M. plrtnizrscu/115 group in the Mediterranean region. We also inferred possible dynamics in the radiation of the Mt’/{get/Jr’: plmz/'1z.rr:11l1t.r complex within Macaronesia utilizing morphological, molecular and bionomical data, exploring potential historical and palaeoecological scenarios regulated by a molecular clock dating system. We reconstructed phylogenetic relationships of the M. p/zznizzxcu/115 complex and of related Mediterranean (ll/I. zfistis), tropical (ll/I. ream) and soud1ern African (/l/I. c/Jeuro/ati, /VI. rmzfizrmir, and /l/I.fiqm‘1'm/zz) species, using CO1 mitochondrial gene sequences. Phylogenetic reconstructions support an unambiguous distinction of two major clades grouping European—Mediterranean M czzmtriensir, ll/I. iroplexidit and ll/I. [1/arziiuczz/11: specimens in one clade and the South—African specimens related to Mfi*z/fica/a in another. Molecular markers suggested that the European— Mediterranean taxon Il/I. tristi: is unambiguously more distantly related to the partly sy1npatricM £1171/z7'I'mxi:, M. iso/7/exit/it and M p/mzimcu/m, than to the geographically isolated Southern African taxon, /l/I. fivzfiw/:1. However, morphological data revealed that /l/[. t7'i.rtz': is more closely related to A4. p/tzriiitmz/1/5 and its allies while occupying a position internal to the [VI /2/rzzzimcnl1z.r species group, but external to the A/[. p/arlizlmzlrzs complex. Results of divergence estimation analyses suggest a splitting between ancestors of the European-Mediterranean species of the M. p/tzzzirzrcu/zzr complex and that of the African species M. flzitica/(I at —2l—23 MYA. Molecular results also demonstrated that the remaining Afrotropical species are more related to the M p//zniz/5:1//m and A4. fi'z/rim//1 complexes than to M. trirtis. This evidence clearly indicates that the Holarctic M. ]1/zzziimczz/11: group represents a paraphyletic assemblage with heterochronic Afrotropical origin. The estimated times of divergence supports evidence from other researchers of an ‘Arid Corridor’, or of a ‘Central or Eastern

The biogeographical patterns of disjunt distribution with special emphasis on the Mediterranean and southern African model

Biogeographia vol. XXIX — 2008 (Pubblicato il 30 dicembre 2008) The Mediterranean—southern African disjunct distribution pattern The biogeographical patterns of disjunct distribution with special emphasis on the Mediterranean and southern African model MARCO A. BOLOGNA, PAOLO A. AUDlSIO*, MAURIZIO BlONDI**, ACHILLE CASALE*** Dipzzrtimmto di Biologia Arnbientrzle, Um'z/erritfz Roma Tre, via/e G. Marconi 446, 00146 Rome, Italy e—mzzz'[: bologna @um'r0mrz3. it *Dz}uzrtz'me7zto di Biologirz Arzimzzle e a'el[’U0mo, Sapienza Universitfz dz’ Roma, z/idle del/’Uniz2er5z't£z 32, 00185 Rome, Italy ”‘*Dz‘pzzrtimmto di Scienze Am/vientzzli, Universitfz del/1/lqziilzz, via Vetoio 57%‘, 67100 L i/lqui/zz, Italy ***Dz‘partin2e7zto di Z00/ogia e Gmetiaz evoluzionistiaz, Universitiz di Sasszzri, Via Muroni 25, 07100 Szzmzri, Italy Key words: biogeographical models, disjunction, Mediterranean, southern Africa SUMMARY The authors introduce and shortly discuss the intriguing issue of biogeographical disjunctions, with special emphasis on the Mediterranean—southern African disjunctions, analyzed considering both dispersal and vicariance models. Combined data sets based on both mot holo ical and molecular cues from a relativel lar 6 series ofdifferent . P . . . . V g . . animal and ve etal taxa some of them extensivel discussed in the resent volume) indicate true and si nificant E . . _ Y _ _ 5 _ phylogenetic relationships between Mediterranean and southern African biota. Where molecular data are available, . . . - a . . ., (L the estimated times of divergence frequently supports evidence of an Arid Corridor , or of a Central or Eastern High Africa Corridor”, which connected a number of times in the last 20—25 MY s the European—Mediterranean and eastern/southern African areas, and facilitated species migration northwards and southwards. These corridors allowed the dispersal southwards of several taxa of European—Mediterranean origin, frequently teaching at least the main mountain systems and the coasts of Eastern and SE Africa. On the other hand, several taxa of eastern and southern African origin migrated northwards, colonizing the Mediterranean and southern Palaearctic areas. Finally, secondary radiations at specific level frequently occurred in the last MYs both in Mediterranean and African areas, involving taxa of African and Mediterranean origins, respectively. INTRODUCTION Among the most relevant topics in biogeography, a fundamental role is played by the analysis of the origin and theevolutionary timing of disjunct

A contribution to the phylogeny of the elephant shrews (Mammalia, Macroscelidea)

Biogeographia vol. XXIX — 2008 (Pubb/icato il 30 dicembre 2008) The Mediterranean—southern African disjunct distribution pattern A contribution to phylogeny of the elephant shrews (Mammalia, Macroscelidea) MASSIMILIAN O SCALICI, FABIANA PANCHETTI, GIUSEPPE MARIA CARPANETO, GIANCARLO GIBERTINI Dz'prm‘z'77zmto dzq Biologizz e Biologizz Ambientzzle, Unit/ersitfz Roma Tre, 2/2'11 G. Mnrrozzi 446, 00146 Roma, Italy e—mrzz'/.' scrzlici @zmir0mrz3. it; fizbizzizzz. pzztzc/aezti C.3/70177211171. it; crz7prmeL‘@zmz'r07mz3. it; gz'[9errz'n @u72ii'o77zn3. it Key words: geometric morphometric analysis, systematics, hiogeography, Afrotropical Region SUMMARY The main purpose of the present study was to contribute to the systematic debate on the elephant-shrews, an order of mammals endemic to Africa, by comparing biogeographical patterns with the results of the analysis of cranium images using a geometric morphometric approach. A total OFSZ9 images ofdorsal and lateral crania ofadult specimens belonging to all the living genera and 13 species were analyzed. The cranial Features that distinguished the subfamily Rhynchocyoninae (R/J_1/22:/mcymz) were a consequence of the extreme enlargement of Frontal bones. Instead, within the subfamily Macroscelidinae (ll/Irzcrorcelizicr, E/E’/7/Jllilfll/III, Pen'ot1'I'0mm‘), the differences between genera were based on modification involving other bones, mainly mastoids and nasals, as shown by the deformation grids. A cluster analysis confirmed the traditional subdivision in the two subfamilies, but suggested a dil'Terent relationship among the recognized genera belonging to Macroscelidinae. Our results also support the monophily ofthe genus E/ep/miztzz/ur and its closeness with Penna/rzmzzzs, relating to their similar cranium shapes. The latter presumably is a case ofgigantism as adaptation to forest habitats. Subsequently, the aclaptative radiation of E/ep/Jmztn/I1: drove the savannas—dwelling species. We retain that the separation of P. remit/rIc't_.)//its and E. rozeti from their common ancestor could have occurred before the splitting of the other E/ep/Jmttlz/I/I species, conserving some plesiomorphies in the cranium of these two species. The colonization OFNW Africa by E. rozeri is the result ofa vicariant event in which the Sahara desertification was instrumental. Further studies on all the species of E11’/1/Jrllititlm could provide new evidence for assessing the relationships within this clade, including ]V[zzcra.w:c/1'tz'e5 that appeared as a well—distinguished taxonomic entity. INTRODUCTION Living elephant shrews are an African endemic order, mouse—lil(e in appea- rance, small—bodied, cursorial and saltatorial, insectivorous and omnivorous, placental mammals (Corhet & Hanks, 1968; Kingdon, 1974; Rathbun, 1979). Elephant shrews originated from Africa and never spread out of this continent (Patterson, 1965). Recent molecular studies of mammalian phylogeny evi- denced that this clade belong to Afrotheria, the latter also involving elephants,

Assessing relationships between Mediterranean and Afrotropical taxa of Cleonini (Coleoptera: Curculionidae: Lixinae): a survey based on Bayesian analysis and lineage geohistory reconstruction

Blogeographia vol. XX/X - 2008 (Pubblicato il 30 dicembre 2008) The Mediterranean-southern African disjunct distribution pattern Assessing relationships between Mediterranean and Afrotropical taxa of Cleonini (Coleoptera: Curculionidae: Lixinae): a survey based on Bayesian analysis and lineage geohistory reconstruction MASSIMO MEREGALLI, DANIELE SILVESTRO Dzjnzrtiiizmto 512' Bio/ogizz Animzzle .9 ale//’U0m0, Um'1/erszriz di Torino 2/in Amza'e772ia A/bertzizzz 13, 10123 T072320 (Italy) e—mzzz'[: 77znr5in2o. meregzz[li@zim't0. it Key words: Curculionidae, Cleonini, African Fauna, Mediterranean Fauna, phylogenetic relationships, Bayesian analysis, historical biogeography. SUMMARY Relationships between the Mediterranean and southern African genera oFCleonini (Curculionidae) were assessed using preliminary phylogenetic analysis and palaeohistorical reconstruction by maximum likelihood inference of ancestral distributions. Intergeneric relationships were found to be present only between sister taxa belonging to basal branches of the trees, suggesting that the faunas of the two regions were connected only during the early stages of radiation ofthe tribe. A critical revision ofthe species composition ofsome Afro—Mediterranean genera revealed that only Pram/oremizoriiyinzir has a disjunct Mediterranean—southern African distribution. This is regarded as having been determined by a recent expansion of the range of the genus from the Mediterranean region towards southern Africa via the eastern Africa grasslands. INTRODUCTION The Curculionidae subfamily Lixinae Schoenherr, 1823 is composed of about 100 genera, presently included in three tribes: Lixini Schoenherr, 1823; Rhinocyllini Lacordaire, 1863; and Cleonini Schoenherr, 1826. This last tribe accounts for most of the genera, more than 80. Its taxonomy is still based on Faust (1904), who also provided the only available key to all the genera. Lacking any comprehensive and comparative evaluation of characters, genera are not always clear and unequivocal; in some cases they seem to be para- phyletic taxa, with uncertain boundaries. A phylogenetic analysis of the tribe

Angiosperm disjunction "Campos rupestres - restingas": a re-evaluation

A disjunct distribution pattern between the extrazonal formations of the campos rupestres (rocky grasslands) in the Espinhaço mountain range and the restingas (coastal strand vegetation) in Brazil has been proposed repeatedly for several flowering-plant species. In order to validate this distribution pattern, available data from the literature and major herbaria were compiled and evaluated. Some of these species also occur in campos rupestres on mountain ranges in Goiás state, campos de altitude (high altitude grasslands) of the Serra do Mar, and on geologically homologous rocky formations of the Guyana shield. Species that were also recorded for distinct zonal formations like cerrado, caatinga and forests were excluded from the pattern. The campo rupestre-restinga disjunction proved valid for 9 of 56 investigated species (16%). Explanations put forth by different authors for this unusual disjunction pattern are compared in the light of geological and climatological evidence.

The delimitation of Antarctic and bipolar species of neuropogonoid Usnea ( Ascomycota, Lecanorales): a cohesion approach of species recognition for the Usnea perpusilla complex

Species of the Neuropogon group in the lichen genus Usnea have their centre of distribution in polar regions of the Southern Hemisphere. Their morphological and chemical variability is poorly understood and several asexual taxa with uncertain relationships to fertile taxa occur in the group. The species concept is controversial. A phylogenetic analysis revealed three related complexes of mainly asexual lineages arranged around three fertile Usnea species: U. aurantiaco-atra, U. trachycarpa and U. perpusilla. In this study a dataset of 80 specimens was used to resolve species circumscriptions in the U. perpusilla complex. We used a phylogenetic and a haplotype network approach based on three gene fragments (ITS, IGS and RPB1) to detect distinct lineages. To support the hypothesis that these lineages represent different species, we tested for correlation of morphological and chemical characters with hierarchical nested haplotype groups, employing statistical tests of contingency tables and analysis of variance (ANOVA). This cohesion species recognition method detected three fertile U. perpusilla lineages. We could also delimit an undescribed fertile species with yellow apothecia and a new asexual species from the High Andes. Interestingly, there is an additional bipolar species, U. lambii, which was formerly confused with U. sphacelata. The fact that U. lambii shows a geographically disjunct distribution pattern, but the genetic distances among specimens are low, points to recent long-distance dispersal.

The genetic variation and biogeography of catostomid fishes based on mitochondrial and nucleic DNA sequences

The genetic variation, phylogeny and biogeography of catostomid fishes were investigated based on mitochondrial cytochrome b and nuclear 18S‐ITS1‐5.8S DNA sequences. The pair‐wise genetic distance of cytochrome b for 17 catostomids varied considerably, from 1·00% (Chasmistes brevirostris and Deltistes luxatus) to 23·3% (Cycleptus elongatus and Moxostoma anisurum). The size of the 18S‐ITS1‐5.8S sequence ranged from 315 bp (Moxostoma robustum) to 575 bp (Ictiobus cyprinellus). The 18S‐5.8S region was conservative and the length of ITS1 regions was found to vary considerably among the seven catostomids. It is interesting that the primitive I. cyprinellus and Myxocyprinus asiaticus had longer ITS1 regions than suckers from the Catostominae. Based on the nucleotide substitution model, the nuclear 18S‐5.8S gene had a faster evolution rate than the mitochondrial cytochrome b gene. In a phylogenetic analysis, 17 catostomids from 14 genera representing three subfamilies were not distinctly divergent. Nevertheless, three major genetically divergent clades were identified. Clade I (95% bootstrap) included general Catostomus, Thoburnia, Xyrauchen, Chasmistes and Deltistes. Clade II (94% bootstrap) included Hypentelium, Moxostoma and Scartomyzon. Clade III (77% bootstrap) was a monophyletic Ictiobinae containing I. cyprinellus and Carpiodes carpio. The biogeography of old world catostomids followed a disperse event, and the speciation of the extant catostomids was a vicariance event. The earliest catostomid evolved in Asia from one branch of ostariophysans in the early Tertiary. Before the Eocene, catostomids belonging to the genus Amyzon had a wide, trans‐Pacific distribution over Asia and North America. Later, oceanic ingression and the Tertiary glacial event forced catostomids to evolve on both mainlands, respectively. The present disjunct distribution pattern of catostomids was presumably due to competitive pressure from cyprinids, geographical events, their Late Cenozoic radiation in North America and glacial events. The divergence time based on the mitochondrial and nuclear DNA sequences suggests that catostomids began to diverge in the early or mid‐Miocene, which agrees with the fossil evidence.

Generic delimitation and biogeography of Maianthemum and Smilacina (Ruscaceae sensu lato): preliminary results based on partial 3′ matK gene and trnK 3′ intron sequences of cpDNA

The controversy over generic delimitation between Maianthemum and Smilacina has been unresolved for almost two centuries. Distributions of the two genera in the Northern Hemisphere also provide an excellent opportunity to further understand the disjunct distribution patterns of the North Temperate Flora. To test the generic delimitation and to investigate biogeographic patterns, we sequenced the partial 3′ matK gene and trnK 3′ intron of chloroplast DNA for 38 accessions, representing three species of Maianthemum, seven species of Smilacina, and four outgroup taxa. Maximum parsimony and neighbor-joining trees showed reciprocal monophyly of the two genera with very weak bootstrap support for each genus. Within each genus, relationships among species were poorly resolved. Despite its low resolution, this study shows that eastern Asian species of Smilacina and Maianthemum are generally more closely related to eastern North American taxa than to western ones. More detailed sampling of Smilacina from different geographic regions, especially from the two centers of diversity (southeastern Asia and Mexico/Central America), and additional sequences from cpDNA, as well as from nuclear DNA, are needed to test the reciprocal monophyly of the two genera and also to understand current distributions of disjunct taxa.

Insights into the Biogeography of the Pacific Northwest of North America: Evidence from the Phylogeography of <I>Salix melanopsis</I>

Abstract The disjunction of the mesic coniferous forests of the Pacific Northwest (PNW) has long been of interest to biogeographers, and several hypotheses have been posed to explain the disjunct distribution pattern. Analysis of intraspecific chloroplast DNA variation (1785 bp of matK and 400 bp of rpl16) in Salix melanopsis allows these hypotheses to be tested. Our study confirmed the existence of three genetic races (uncorrected sequence divergence ranged from 0.7-1.1%) within the species, which differ in distribution and ecology. The mesic race, associated with mesic coniferous forests, was the focus of this study. This race consists of two major lineages (uncorrected sequence divergence ranged up to 0.28%), one of which is associated with an apparent glacial refugium south of glaciation in the northern Rocky Mountains. The three haplotypes that comprise the first lineage are largely segregated into separate river canyons that comprise the “Greater Clearwater Refugium”. The other major lineage include...

Application of Predictive Distribution Modelling to Invertebrates: Odonata in South Africa

The application of distributional modelling techniques to invertebrates has seldom been explored, primarily due to a lack in adequate distributional data for these taxa. Here, we have selected a simple modelling approach for the generation of distribution maps from a limited dataset, as a first step to the atlassing of Odonata in South Africa. The BIOCLIM-type approach was selected for this purpose, as it requires minimal data for model building and validation procedures. BIOCLIM partitions an area climatically prior to survey, and predicts species distributions on a bioclimatic basis. Conservative deterministic models were developed using point presence/absence data for each of the regions' 160 described species. These models were validated by cross-validation, and the Jaccard coefficient of similarity was used as an index of model performance. A sensitivity analysis investigated the influence of extreme values and errors in the data on predictive ability. Models identified disjunct distribution patterns and accurately predicted the restricted ranges of habitat-specialist species. However, models overstated the distribution of habitat generalists and species with distinct outlier records. For accurate predictions of broad-ranging species, it is suggested that a probabilistic approach be adopted. Nevertheless, basic distribution patterns generated through this conservative approach can be further applied to the investigation of species richness and issues relating to conservation, such as reserve design. The BIOCLIM-type approach provided a means of predicting species distributions, allowing for broad-scale atlassing and thereby providing the first step towards Odonata conservation in South Africa.

Phylogeography of Japanese alpine plants: biogeographic importance of alpine region of Central Honshu in Japan

AbstractA preliminary synthesis of the geographic distribution patterns of intraspecific cpDNA variations in Japanese alpine plants is presented by studying five species, namely, Pedicularis chamissonis, Primula cuneifolia, Loiseleuria procumbens, Cardamine nipponica, and Anemone narcissiflora. Nucleotide sequences of the noncoding regions of cpDNA recognized multiple cpDNA haplotypes in these species. Phylogenetic analyses of these haplotypes suggest two or three major cpDNA clades; each clade has a clearly disjunct distribution pattern in the northern parts of Japan, and in the central parts of Japan. The southernmost clades endemic to central Honshu in Japan were found in all the species (Central Honshu clade). We estimate that the major clades of Pedicularis chamissonis and Primula cuneifolia separated from a common ancestor before the last glacial period (>0.6 and 0.47 million years ago, respectively). We speculate that the common distribution patterns of the cpDNA clades observed in central Honshu were formed by dynamic climatic changes (e.g., glacial events in the Pleistocene) and that the alpine regions of central Honshu acted as refugia for alpine plants during warm interglacial periods.

Disjunct distributions during glacial and interglacial periods in mountain butterflies: Erebia epiphron as an example

Over several decades, the distribution patterns and evolution of alpine disjunct species has become an increasingly discussed subject. Large scale genetic analysis has allowed the resolution of the past range changes and intraspecific evolution of many species, in Europe especially of Mediterranean origin. However, the phylogeographic structures of species with arctic-alpine disjunct distribution patterns are relatively poorly studied. The existing phylogeographic analysis (mostly of alpine plant species) supports disjunct distributions during glacial as well as post-glacial periods for a number of species. However, several questions still remain unresolved and we therefore analysed the Mountain Ringlet Erebia epiphron as a model for such alpine disjunct species. We found strong differentiation into five different lineages supporting five differentiation centres: (i) the eastern Pyrenees, (ii) the mountain ranges between the central Pyrenees and south-western Alps, (iii, iv) two areas along the southern Alps margin and (v) the northern Alps margin. We propose that these patterns evolved due to the humidity requirements of this species, which did not allow survival in the dry glacial steppes, but along the margins of the wetter glaciated high mountain ranges.

Relict islands of the temperate rainforest tree Aextoxicon punctatum (Aextoxicaceae) in semi-arid Chile: genetic diversity and biogeographic history

Aextoxicon punctatum, the only representative of the family Aextoxicaceae, is a tree species endemic to temperate forests of western South America. This species exhibits a disjunct distribution pattern, with few isolated populations occurring on coastal hilltops of the Chilean semi-arid zone (SAZ), 30–32°S; small populations mixed with sclerophyllous forest in some gorges of the central Chilean Mediterranean coastal range (MCR), 32–39°S; more continuous forests extended along the southern temperate coastal range (TCR), 39–43°S; and fragmented populations eastward in the south temperate central depression and Andean foothills (TAF), 39–41°S. This geographic disjunction is the result of climatic and tectonic changes that took place in southern South America since the late Tertiary, leading to the isolation of forest fragments in the SAZ from the rest of the distribution. According to palynological evidence, populations of TCR and TAF originated from postglacial population expansions from refuges located on the coastal range, north of 40°S. We examined how the present genetic structure and diversity of Aextoxicon populations in Chile reflects this biogeographic history. Random amplified polymorphic DNA (RAPD) markers were used to characterise genetic differences within and among 16 populations of this species throughout its natural range. AMOVA and UPGMA analysis showed high genetic differentiation between the geographically closer SAZ and MCR populations, suggesting a long history of restricted genetic exchange between populations in these two zones. Estimates of Shannon’s genetic diversity and percentage polymorphism were relatively low compared with other southern temperate forest trees (mainly conifers) that were less affected by the glaciations. Positive correlations between genetic and geographic distances were found for TCR but not for TAF populations, suggesting earlier postglacial population expansion southwards along the TCR and more recent eastward migration from coastal locations to TAF during the Holocene.

The cytology of Actinidia, Saurauia and Clematoclethra (Actinidiaceae)

Meiosis and mitosis of six Chinese Actinidiaceae were studied: Saurauia tristyla DC., S. miniata C. F. Liang & Y. S. Wang, Actinidia chinensis Plach., A. deliciosa (Cheval.) C. F. Liang & A. R. Ferguson, A. indochinensis Merr. and Clematoclethra lasioclada Maxim. The chromosome numbers of Saurauia tristyla and S. miniata were 2n = 6x = 78, establishing a base chromosome number of x = 13 in the genus, differing from the previous report of x = 15. The chromosome number of Clematoclethra was first reported to be 2n = 4x = 48 (x = 12), while that of Actinidia was x = 29, consistent with previous reports. The base chromosome number of Clematoclethra (x = 12) was derived from an aneuploid decrease from Saurauia (x = 13). Actinidia (x = 29) was derived from the palaeotetraploid (x = 14), which was formed through the increase of the basic chromosome number x = 13 to x = 14 by aneuploidy and through the breakage of a centromere to add one more new chromosome. The chromosome data in Actinidia were consistent with the geographical and morphological evidence for the evolution of the three genera. The tropical American and Asian disjunct distribution pattern and the diversity of base chromosome numbers of Saurauia further support the probability that the genus was an early divergent from a common ancestor of Actinidia and Clematoclethra. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 147, 369–374.

Lichens and ultramafic rocks: a review

Floristic, vegetational and ecological features of lichens in ultramafic environments are reviewed using a wide range of literature dating from the beginning of the 20th century. Co-presence of acidophytic (silicicolous) and basiphytic (calcicolous) species and the occurrence of species characterized by particular (disjunct) distribution patterns are features of lichens in ultramafic environments. It is not possible to detect consistent trends in data on other broadly accepted features, such as paucity of species, low cover and the occurrence of particular ecotypes because of the influence of several environmental factors in addition to the substratum. Some recent data about physico-chemical interactions between saxicolous lichens and ultramafic rocks are also reported.

Assessment of the Neotropical dry forest refugia hypothesis in the light of palaeoecological data and vegetation model simulations

AbstractSeasonally dry tropical forests exhibit a markedly discontinuous, disjunct distribution pattern across South America. Previous botanical inventories have revealed that these dry forest areas exhibit close floristic links with one another, which has led to the hypothesis that they constitute modern‐day refugia, resulting from vicariance (i.e. fragmentation) of a formerly more widespread, continuous distribution during more arid climatic conditions associated with the Last Glacial Maximum (LGM). This paper examines the validity of this ‘dry forest refugia’ hypothesis in the light of previously published fossil pollen data and vegetation model simulations. The model simulations suggest that major dry forest areas, such as the Bolivian Chiquitano Dry Forest, are not Pleistocene refugia, but instead developed during the Holocene by population expansions from parts of southern Amazonia presently covered by evergreen rainforest. The limited pollen data available indicate that glacial‐age seasonally dry tropical forests, irrespective of their distribution, were floristically quite different from those of today, with key dry forest species, such as Anadenanthera, only appearing in the Holocene. I suggest that a more parsimonious explanation for the current biogeographic pattern of these South American dry forests is population migration (perhaps by long‐distance dispersal) since the LGM, rather than vicariance. Copyright © 2004 John Wiley & Sons, Ltd.

Taxonomic and phytogeographic implications from ITS phylogeny in Berberis (Berberidaceae).

A phylogeny based on the internal transcribed spacer (ITS) sequences from 79 taxa representing much of the diversity of Berberis L. (four major groups and 22 sections) was constructed for the first time. The phylogeny was basically congruent with the previous classification schemes at higher taxonomic levels, such as groups and subgroups. A notable exception is the non-monophyly of the group Occidentales of compound-leaved Berberis (previously separated as Mahonia). At lower levels, however, most of previous sections and subsections were not evident especially in simple-leaved Berberis. Possible relationship between section Horridae (group Occidentales) and the simple-leaved Berberis clade implies paraphyly of the compound-leaved Berberis. A well-known South America-Old World (mainly Asia) disjunctive distribution pattern of the simple-leaved Berberis is explained by a vicariance event occurring in the Cretaceous period. The ITS phylogeny also suggests that a possible connection between the Asian and South American groups through the North American species ( Berberis canadensis or B. fendleri) is highly unlikely.

PHYLOGEOGRAPHY OF THE PLANKTONIC CHAETOGNATH SAGITTA SETOSA REVEALS ISOLATION IN EUROPEAN SEAS

Numerous planktonic species have disjunct distribution patterns in the world's oceans. However, it is unclear whether these are truly unconnected by gene flow, or whether they are composed of morphologically cryptic species. The marine planktonic chaetognath Sagitta setosa Müller has a discontinuous geographic distribution over the continental shelf in the northeastern Atlantic, Mediterranean Sea, and Black Sea. Morphological variation between these populations has been described, but overlaps and is therefore unsuitable to determine the degree of isolation between populations. To test whether disjunct populations are also genetically disjunct, we sequenced a 504-bp fragment of mitochondrial DNA comprising the cytochrome oxidase II region of 86 individuals. Sequences were highly variable; each represented a different haplotype. Within S. setosa, sequence divergence ranged from 0.2 to 8.1% and strong phylogeographic structure was found, with four main groups corresponding to the northeastern Atlantic, Mediterranean Sea (including Ligurian Sea, Tyrrhenian Sea and Gulf of Gabès), Adriatic Sea, and Black Sea. Two of these (Atlantic and Black Sea) were resolved as monophyletic clades, thus gene flow between disjunct populations of S. setosa has been extremely limited and lineage sorting has taken place. The deepest divergence was between Atlantic and Mediterranean/Black Sea populations followed by a split between Mediterranean and Black Sea populations. The Mediterranean/Black Sea clade comprised three groups, with the Adriatic Sea as the most likely sister clade of the Black Sea. These data are consistent with a colonization of the Black Sea from the Mediterranean. Furthermore, a possible cryptic species was found in the Black Sea with 23.1% sequence divergence from S. setosa. Two possibilities for the evolutionary origin of this species are proposed, namely, that it represents a relict species from the ancient Paratethys, or that it represents another chaetognath species that colonized the Black Sea more recently. Even though the exact timing of disjunction of S. setosa populations remains unclear, on the basis of the geological and paleoclimatic history of the European basins and our estimates of net nucleotide divergence, we suggest that disjunct populations arose through vicariance resulting from the cyclical changes in temperature and sea levels during the Pleistocene. We conclude that these populations have remained disjunct, not because of limited dispersal ability, but because of the inability to maintain viable populations in suboptimal, geographically intermediate areas.

Historical biogeography and phylogenetic relationships of the genus Chamaecyparis (Cupressaceae) inferred from chloroplast DNA polymorphism

The genus Chamaecyparis comprises five species and one variety native to Taiwan, Japan, Canada, and USA, which demonstrates a classical eastern Asian, western North American, and eastern North American disjunct distributional pattern. The phylogenetic relationships of the species of Chamaecyparis were inferred by comparing 1130 bp of the combined data set of chloroplast trnV intron and petG-trnP intergenic spacer. The phylogenetic tree shows that Chamaecyparis nootkatensis (Cupressus nootkatensis or Xanthocyparis nootkatensis) is clearly diverged from other Chamaecyparis species. For Chamaecyparis species, C. thyoides is sister to C. formosensis and C. pisifera and these together form a monophyletic group. C. lawsoniana is sister to C. obtusa and C. taiwanensis; and these form another monophyletic group. Homogeneity in evolutionary rates was found among species in these two monophyletic groups. Results indicate the divergent evolution of C. taiwanensis and C. formosensis and molecular evidence in this investigation supports C. taiwanensis as a variety of C. obtusa. Utility of cpDNA intergenic spacer petG-trnP in Chamaecyparis is also discussed. Several biogeographical implications were inferred: (1) at least two divergence events have produced the eastern Asian, and both western and eastern North American disjunct distribution in Chamaecyparis; (2) intercontinental sister species pairs are found in Chamaecyparis; (3) cpDNA divergence between two intercontinental sister pairs of C. thyoides and C. pisifera, and C. lawsoniana and C. obtusa is 2.8% and 1.1%, which suggest an estimated divergence time of 14 and 5.5 million years ago during middle and late Miocene, respectively; (4) cpDNA divergence of two Asian Chamaecyparis groups between C. obtusa and C. taiwanensis, and between C. pisifera and C. formosensis is 0.25% and 0.57%, which suggest an estimated divergence time of 1.3 and 2.9 million years ago during Pleistocene and late Pliocene, respectively; these estimated divergence times suggest a relatively recent migration of Chamaecyparis to Taiwan from the Japanese Archipelago; (5) that climatic deterioration caused the disappearance of Chamaecyparis in continental Asia is probable.