Phylogeography of a Patagonian lizard and frog: Congruent signature of southern glacial refuges

Pleistocene glaciations produced significant increases in continental ice cover in polar and mid‐latitude temperate areas, sea‐level declines and shifts and reshuffling of biomes, all of which promote either isolation, coalescence or fragmentation in the distribution of land biota. If populations of several taxa have been co‐distributed for a prolonged time, and if the periods between perturbation or vicariance processes have been more or less stable, it is expected that divergence patterns of closely related and ecologically similar species will be congruent because of their similar biological and demographic characteristics. Based on this premise, we analysed the phylogeographic structure (cytochrome b) of Liolaemus pictus and Batrachyla leptopus, two widely co‐distributed lizard and frog species, respectively, in the Chiloé Archipelago of southern Chile, to decipher their genetic structure in response to a common climatic and environmental history. Haplotype network analysis and Bayesian inference suggest an evolutionary pattern of genetic diversity for the two species that is consistent with the Quaternary glacial history of southern Chile, and suggests a complex phylogeographic history in the Liolaemus and Batrachyla species. High‐divergence levels among haplotypes in some island populations of the archipelago also suggest genetic connectivity between putative refuges from Chiloé Island and the mainland along the exposed continental shelf during sea level minima associated with the most recent Quaternary glaciations. Our results are consistent with our hypothesis that two species have responded to parallel historical events in which the historical process during the last glacial maximum (approximately 41°S) has been sufficient to influence their phylogeographic structure.     

Phylogeography of the Percichthyidae (Pisces) in Patagonia: roles of orogeny, glaciation, and volcanism

We used molecular evidence to examine the roles that vicariance mechanisms (mountain-building and drainage changes during the Pleistocene) have played in producing phylogeographical structure within and among South American fish species of the temperate perch family Percichthyidae. The percichthyids include two South American genera, Percichthys and Percilia, each containing several species, all of which are endemic to southern Argentina and Chile (Patagonia). Maximum-likelihood phylogenies constructed using mitochondrial DNA (mtDNA) control region haplotypes and nuclear GnRH3-2 intron allele sequences support the current taxonomy at the genus level (both Percichthys and Percilia form strongly supported, monophyletic clades) but indicate that species-level designations need revision. Phylogeographical patterns at the mtDNA support the hypothesis that the Andes have been a major barrier to gene flow. Most species diversity occurs in watersheds to the west of the Andes, together with some ancient divergences among conspecific populations. In contrast, only one species (Percichthys trucha) is found east of the Andes, and little to no phylogeographical structure occurs among populations in this region. Mismatch analyses of mtDNA sequences suggest that eastern populations last went through a major bottleneck c. 188 000 bp, a date consistent with the onset of the penultimate and largest Pleistocene glaciation in Patagonia. We suggest that eastern populations have undergone repeated founder-flush events as a consequence of glacial cycles, and that the shallow phylogeny is due to mixing during recolonization periods. The area of greater diversity west of the Andes lies outside the northern limit of the glaciers. mtDNA mismatch analysis of the genus Percilia which is restricted to this area suggests a long-established population at equilibrium. We conclude that patterns of genetic diversity in these South American genera have been primarily influenced by barriers to gene flow (Andean orogeny, and to a lesser extent, isolation in river drainages), and by glacial cycles, which have resulted in population contraction, re-arrangement of some watersheds, and the temporary breakdown of dispersal barriers among eastern river systems.     

mtDNA microevolution in Southern Chile's archipelagos

The genetic variability of four predominantly Indian populations of southern Chile's archipelagos was examined by determining the frequencies of four mitochondrial DNA haplogroups that characterize the American Indian populations. Over 90% of the individuals analyzed presented Native American mtDNA haplogroups. By means of an unweighted group pair method with arithmetic mean (UPGMA) dendrogram, a principal component analysis (PCA) derived from a distance matrix of mtDNA, and the exact test of population differentiation, we are able to prove the existence of a North‐South cline. The populations in the northern part of the archipelagos are genetically similar to the Huilliche tribe, while the groups from the South are most closely related to the Fueguino tribe from the extreme South of Chile, and secondarily to the Pehuenche and Mapuche, who are found to the North and East of Chiloé archipelago. These results are consistent with a colonization of the southern archipelagos from Tierra del Fuego. We evaluate the evolutionary relationships of the population of the Chiloé area to groups from other geographic areas of Chile, using analysis of molecular variance (AMOVA). Three Amerindian clusters are identified: one formed by the Aymará and Atacameño, a second by the Huilliche, and a third including the Mapuche, Pehuenche, and Fueguino tribes, and the population inhabiting the South of the Chiloé arcipelago. These groups exhibit a North‐South gradient in the frequency of haplogroup B, confirmed by F_ST tests. Am J Phys Anthropol, 2006 © 2005 Wiley‐Liss, Inc.     

Phylogeography and population history of Leopardus guigna,the smallest American felid

The guigna (Leopardus guigna) is the smallest and most-restricted New World cat species, inhabiting only around 160,000 km² of temperate rain forests in southern South America and is currently threatened by habitat loss, fragmentation and human persecution. We investigated phylogeographic patterns of genetic diversity, demographic history and barriers to gene flow with 116 individuals sampled across the species geographic range by analyzing 1,798 base pairs of the mtDNA (496 bp HVSI region, 720 bp NADH-5 gene, 364 bp from 16S gene and 218 bp from ATP-8 gene) and 15 microsatellite loci. Mitochondrial DNA data revealed a clear phylogeographic pattern with moderate separation between northern and southern Chilean populations supporting recognized subspecific partitions based on morphology. A recent demographic expansion was inferred for the southern-most group (San Rafael Lake), presumably due to the complete coverage of this area during the last glacial period, 28000–16000 years BP. Geographical barriers such as the Andes Mountains and the Chacao Channel have partially restricted historic and more-recent gene flow and the Chiloé Island population has diverged genetically since being separated from the mainland 7000 years BP. This is the first study of the genetic structure of this threatened species throughout its whole geographic range.     

Pleistocene refugia in an arid landscape: analysis of a widely distributed Australian passerine

While many studies have documented the effect that glacial cycles have had on northern hemisphere species, few have attempted to study the associated effect of aridification at low latitudes in the southern hemisphere. We investigated the past effects that cyclic aridification may have had on the population structure and history of a widespread endemic Australian bird species, the Australian magpie (Gymnorhina tibicen). One thousand one hundred and sixty-six samples from across its native range were analysed for mitochondrial control region sequence variation and variation at six microsatellite loci. Analysis of mitochondrial control region sequence data indicated monophyletic clades that were geographically congruent with an eastern and western region. The contemporary distribution of east and west clades is nonoverlapping but in close proximity. Populations were estimated to have diverged in the Pleistocene around 36,000 years ago. The putative Carpentarian and Nullarbor arid barriers appear to be associated with the divergence between east and west mainland populations. Nested clade analysis indicated a signature of range expansion in the eastern region suggesting movement possibly inland and northward subsequent to the last period of aridity. The island population of Tasmania was of very recent origin, possibly since sea levels rose 16,000 years ago. Given the east-west structure, there was no congruence between morphology and recent history of this species indicating a lack of support for morphological taxa. Overall mitochondrial DNA and microsatellite variation suggest that increasing aridity and Pleistocene refugia played a role in structuring populations of the Australian magpie; however, the dispersal ability and generalist habitat requirements may have facilitated the movement of magpies into an almost contiguous modern distribution across the continent. This study supports the idea that Pleistocene aridification played an important role in structuring intraspecific variation in low latitudinal southern hemisphere avian species.     

Intraspecific Phylogeography of Red Squirrels (Tamiasciurus hudsonicus) in the Central Rocky Mountain Region of North America

We used variation in a portion of the mitochondrial DNA control region to examine phylogeography of Tamiasciurus hudsonicus, a boreal-adapted small mammal in the central Rocky Mountain region. AMOVA revealed that 65.66% of genetic diversity was attributable to variation within populations, 16.93% to variation among populations on different mountain ranges, and 17.41% to variation among populations within mountain ranges. Nested clade analysis revealed two major clades that likely diverged in allopatry during the Pleistocene: a southern clade from southern Colorado and a northern clade comprising northern Colorado, Wyoming, eastern Utah, and eastern Idaho. Historically restricted gene flow as a result of geographic barriers was indicated between populations on opposite sides of the Green River and Wyoming Basin and among populations in eastern Wyoming. In some instances genetic structure indicated isolation by distance.     

Genetic diversity and insular colonization of Liolaemus pictus (Squamata,Liolaeminae) in north‐western Patagonia

The Chilotan Archipelago and surrounding areas of north‐western Patagonia (41°–43°S, 72°–74°W) offer a unique opportunity to study the interplay between the recent genetic and paleoenvironmental evolution on temperate rainforest environments. Previous studies in this region have postulated that land biota persisted west of the Patagonian ice sheet, in ice‐free low‐elevation regions of the mainland, and the north‐western portion of Isla Grande de Chiloé during Quaternary ice ages. In this study, we analysed the phylogeographical structure (Cytochrome b) of the iguanid lizard Liolaemus pictus to estimate their genetic structure in response to glacial–interglacial cycles and colonization routes. We found that populations from the mainland and Isla Grande de Chiloé do not share haplotypes and, thus, are divergent haplogroups. This divergence might reflect an ancient isolation, much older than the last glaciation. Moreover, the existence of four divergent haplogroups among L. pictus populations in the mainland suggests the persistence of multiple isolated populations during the last glaciation. Our results also indicate that the colonization of small islands occurred from several source sites, located both in the mainland and in Isla Grande de Chiloé, after the Last Glacial Maximum.     

Phylogeography of the parthenogenic ant Platythyrea punctata: highly successful colonization of the West Indies by a poor disperser

Aim We investigated the spatio‐temporal patterns of genetic diversity in West Indian and mainland populations of a widespread parthenogenic ant (Platythyrea punctata F. Smith) to infer source populations and subsequent colonizations across its geographic range. Location Central America, Texas and the West Indies (Florida, the Bahamas, Greater and Lesser Antilles). Methods We employed phylogeographic reconstruction based on 1451 bp of mitochondrial DNA (cytochrome c oxidase subunits I and II) sequenced from 91 individuals of P. punctata. We employed standard population genetic analyses, Bayesian phylogenetic analyses, haplotype networks and molecular dating methods as performed by beast . We also employed phylogenetic analysis using two nuclear markers (970 bp) to understand the placement of P. punctata in the globally distributed genus Platythyrea. Results Based on highly reduced haplotypic variation and temporal estimates, rapid expansion and dispersal from Central America best explains the observed distribution of haplotypes. Platythyrea punctata successfully invaded the West Indies very few times. One haplotype occurred on every island surveyed from the Bahamas and Florida in the north to Barbados at the southern edge of its range. Haplotype diversity in the West Indies is quite low, despite a larger sample size relative to the mainland. Most mainland colonies collected each possessed a unique haplotype, whereas only Florida and the larger islands (the Dominican Republic, Puerto Rico and Guadeloupe) contained more than one haplotype. Island haplotypes were most similar to haplotypes collected in northern Mexico and southern Texas, but genetic distances were nevertheless high. The putative sister species of P. punctata appears to be an endemic of Hispaniola (P. strenua Wheeler & Mann), even though older, mainland populations of P. punctata are sympatric with at least two other congenerics. Main conclusions Dispersal seems very limited on the mainland, with well‐defined clades corresponding to geographical regions. Colonization of the islands from the mainland was extremely rare, but once successful there were very few barriers to expansion to nearly every island in the West Indies. We hypothesize that this invasion occurred during the late Pleistocene as the climate became warmer and less arid.     

Presence of <Emphasis Type="Italic">Ixodes neuquenensis</Emphasis> Ringuelet, 1947 (Acari: Ixodidae) on the endangered Neotropical marsupial Monito del monte (<Emphasis Type="Italic">Dromiciops gliroides</Emphasis> Thomas, 1894, Microbiotheria: Microbiotheriidae) at Chiloé Island,Chile

The presence of Ixodes neuquenensis (Ringuelet, Notas Mus la Plata 12:207–216, 1947) (Acari: Ixodidae) parasitizing populations of Dromiciops gliroides Thomas, 1894 (Microbiotheria: Microbiotheriidae) at Chiloé Island confirms that this tick species is established in Chile. No preference of the ticks for sex or age of the host was observed.     

Phylogeny, morphology, and biogeography ofChuquiraga, an Andean-Patagonian genus of Asteraceae-Barnadesioideae

Chuquiraga is a genus of 23 species of evergreen shrubs endemic to South America. It is distributed principally along the Andes from Colombia to Chile and Argentina, and it is especially diversified in the Central Andes and in the deserts and semideserts of southern South America. The genus exhibits a wide array of leaf-morphology types and two different head and floral types apparently related to hummingbird and insect pollination. In this study, phylogenetic relationships amongChuquiraga species were resolved by parsimony cladistic analysis using morphological characters. The resulting cladogram was used to interpret morphological, ecological, and biogeographical patterns in a historical context. Biotic and abiotic environmental factors hypothesized to have exerted selective pressure on morphological traits of its species were optimized onto the phylogeny to suggest how and when these factors may have affected the evolution and diversification of the genus. Results suggest an origin of the genus in southern South America, with two major evolutionary radiations, one more northern in the Central and Northern Andes, and the other in the Southern Andes and the North Chilean, Patagonia and Monte Deserts. Pollination by hummingbirds seems to have been an important factor in the origin of the northern clade, affecting floral morphology. Herbivory by vertebrates and increased aridity seem to have been important selective forces in the evolution and diversification of the southern clade, especially affecting leaf morphology. These changes were probably associated with the major elevation of the Andes in late Tertiary and with the hyperaridization and climatic fluctuations of Pleistocene and Holocene times.

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Resumen   Chuquiraga es un género con 23 especies de arbustos perennifolios endémico de América del Sur. Se distribuye principalmente a lo largo de los Andes desde Colombia hasta Chile y Argentina y está especialmente diversificado en los desiertos y semidesiertos de América del Sur. El género presenta un amplio espectro de tipos de morfología foliar y dos tipos florales y de capítulos aparentemente relacionados con la polinización por colibríes y por insectos. En este trabajo las relaciones filogenéticas entre las especies deChuquiraga se resolvieron mediante análisis cladístico de parsimonia utilizando caracteres morfológicos. El cladograma resultante se empleó para interpretar patrones morfológicos, ecológicos y biogeográficos de las especies en un contexto histórico. Factures bióticos y abióticos que se han hipotetizado que han ejercido presión selectiva sobre los caracteres morfológicos fueron optimizados sobre la filogenia para sugerir cómo y cuándo podrían haber afectado la evolución y la diversificación del género. Los resultados obtenidos sugieren un origen del género en el sur de América del Sur, y dos principales radiaciones evolutivas, una más al norte en los Andes Centrales y en los Andes del Norte, y la otra más al sur en los Andes del Sur y en los desiertos del norte de Chile, la Patagonia y el Monte. La polinización por colibríes parece haber sido un factor importante en el origen del clado del norte, afectando la morfología floral. La herbivoría por vertebrados y el incremento en la aridez parecen haber sido fuerzas selectivas importantes en la evolución y diversificación del clado austral, afectando especialmente la morfología foliar. Estos cambios probablemente estuvieron asociados a la elevación máxima de los Andes a fines del Terciario y a la hiperaridización y fiuctuaciones climáticas del Pleistoceno y Holoceno.

     

Phylogeography of the pademelons (Marsupialia: Macropodidae: Thylogale) in New Guinea reflects both geological and climatic events during the Plio‐Pleistocene

Aim Alternative hypotheses concerning genetic structuring of the widespread endemic New Guinean forest pademelons (Thylogale) based on current taxonomy and zoogeography (northern, southern and montane species groupings) and preliminary genetic findings (western and eastern regional groupings) are investigated using mitochondrial sequence data. We examine the relationship between the observed phylogeographical structure and known or inferred geological and historical environmental change during the late Tertiary and Quaternary. Location New Guinea and associated islands. Methods We used primarily museum specimen collections to sample representatives from Thylogale populations across New Guinea and three associated islands. Mitochondrial cytochrome b and control region sequence data were used to construct phylogenies and estimate the timing of population divergence. Results Phylogenetic analyses indicated subdivision of pademelons into ‘eastern’ and ‘western’ regional clades. This was largely due to the genetic distinctiveness of north‐eastern and eastern peninsula populations, as the ‘western’ clade included samples from the northern, southern and central regions of New Guinea. Two tested island groups were closely related to populations north of the Central Cordillera; low genetic differentiation of pademelon populations between north‐eastern New Guinea and islands of the Bismarck Archipelago is consistent with late Pleistocene human‐mediated translocations, while the Aru Islands population showed divergence consistent with cessation of gene flow in the mid Pleistocene. There was relatively limited genetic divergence between currently geographically isolated populations in subalpine and nearby mid‐montane or lowland regions. Main conclusions Phylogeographical structuring does not conform to zoogeographical expectations of a north/south division across the cordillera, nor to current species designations, for this generalist forest species complex. Instead, the observed genetic structuring of Thylogale populations has probably been influenced by geological changes and Pleistocene climatic changes, in particular the recent uplift of the north‐eastern Huon Peninsula and the lowering of tree lines during glacial periods. Low sea levels during glacial maxima also allowed gene flow between the continental Aru Island group and New Guinea. More work is needed, particularly multi‐taxon comparative studies, to further develop and test phylogeographical hypotheses in New Guinea.     

Pleistocene climatic cycling and diversification of the Andean treefrog, Hypsiboas andinus

Our understanding of the causes of diversification of Neotropical organisms lags behind that of Northern Hemisphere biota, especially for montane and temperate regions of southern South America. We investigated the mitochondrial DNA genealogical patterns in 262 individuals of the frog Hypsiboas andinus from 26 sites across the eastern ranges of the Andes Mountains in Argentina and Bolivia. Our phylogenetic analyses indicate at least three distinct lineages: one representing H. andinus from Northwestern Argentina and southern Bolivia, at least one H. andinus lineage from northern Bolivia, and one clade containing both H. andinus (from the southern portion of the species range) and its putative sister taxon Hypsiboas riojanus. Hypsiboas andinus samples from northern Bolivia are well differentiated and may represent distinct species. The northern Argentine H. andinus lineage and southern H. andinus/H. riojanus lineage likely diverged between 2 and 6 million years ago; their current sympatry may be the result of secondary contact due to range expansion after isolation during Andean uplift or may reflect cryptic species. Within the geographically extensive northern H. andinus clade, we found significant geographical structuring consistent with historical fragmentation and subsequent range expansion. The timing of this fragmentation and range expansion coincide with the Pleistocene, a time of extensive climatic cycling and vegetational shifts. Average divergence among clades is lower than those found for other Neotropical taxa, highlighting the potential importance of recent climatic history in diversification in the southern Andes.     

Quinua biosystematics I: Domesticated populations

Domesticated populations of the South American grain chenopod quinua (Chenopodium quinoa subsp.quinoa) have been formally classified on the basis of pigmentation and inflorescence morphology, and informally grouped according to ecotypic variation. Comparative analysis of morphometric and electrophoretic data taken from 98 populations reveals two fundamental elements: a coastal type from southwestern Chile and an Andean type distributed at elevations above 1,800 m from northwestern Argentina to southern Colombia. Andean quinua can be further divided into northern and southern groups, with the northern populations weakly marked by broad, unlobed leaf blades, sharply margined fruit, and relative uniformity. With the exception of allozymes unique to coastal quinua, characteristics that differentiate populations from the Chilean coast and the northern Andes represent a subset of variation present in the southern Andes. This could reflect diffusion from a possible center of origin in the southern highlands. Overall phenetic association places populations from the Altiplano of Peru and Bolivia in a central, linking position. The high genetic identities among all quinua populations argue against a polyphyletic origin for the crop and specific differentiation among cultivar groups. The overall pattern of variation supports the ecotypic approach toward landrace classification of quinua, although congruence between ecological and morphogenetic variation is not complete. While genetic diversity is clearly centered in populations of the southern Andes, conservation efforts should focus on well differentiated quinua populations at the poorly marked northern and southern extremes of distribution.     

Genetic structure of Cydia pomonella populations in Argentina and Chile implies isolating barriers exist between populations

The codling moth (Cydia pomonella (L.)) is an invasive pest of pome fruits introduced to the Americas in the 19–20^th centuries. This pest is widespread on both sides of the Andes range separating Argentina and Chile. We performed an analysis of the population genetic variability and structure of C. pomonella in Argentina and Chile using 13 microsatellite markers and sampled C. pomonella from apple as the main host plant along its distribution area (approx. 1,800 km). A total of 22 locations (11 from Chile and 11 from Argentina) were sampled. Significant genetic differentiation was observed among samples from Argentina and Chile (F_SC = 0.045) and between all localities (F_ST = 0.085). Significant isolation by distance (IBD) was found for each country and when samples from both sides of the Andes range were pooled, although a lower correlation coefficient was observed. The Mantel test showed that the geographic distance and highest altitude of the mountains between locations were significantly associated with the pairwise F_ST when samples from both sides of the Andes range were pooled. According to a Bayesian assignment test (STRUCTURE), samples from Argentina and Chile conformed to two distinct genetic clusters. Our results also suggest that the recent invasion of C. pomonella in the southernmost localities (Aysén Region in Chile and Santa Cruz Province in Argentina) originated in populations from the respective sides of the Andes range. Our results indicate a genetic exchange of C. pomonella within each country and significant genetic differentiation between countries, which could be explained by dispersal mediated by human activities related to fruit production within each country with little exchange between them. A possible explanation is that the Andes range could be a significant barrier for dispersal by flight, and quarantine barriers could prevent the movement of plant material or infested fruit between countries.     

Lizards on Ice: Evidence for Multiple Refugia in Liolaemus pictus (Liolaemidae) during the Last Glacial Maximum in the Southern Andean Beech Forests

Historical climate changes and orogenesis are two important factors that have shaped intraspecific biodiversity patterns worldwide. Although southern South America has experienced such complex events, there is a paucity of studies examining the effects on intraspecific diversification in this part of the world. Liolaemus pictus is the southernmost distributed lizard in the Chilean temperate forest, whose genetic structure has likely been influenced by Pleistocene glaciations. We conducted a phylogeographic study of L. pictus in Chile and Argentina based on one mitochondrial and two nuclear genes recovering two strongly divergent groups, Northern and Southern clades. The first group is distributed from the northernmost limit of the species to the Araucanía region while the second group is distributed throughout the Andes and the Chiloé archipelago in Southern Chile. Our results suggest that L. pictus originated 751 Kya, with divergence between the two clades occurring in the late Pleistocene. Demographic reconstructions for the Northern and Southern clades indicate a decrease in effective population sizes likely associated with Pleistocene glaciations. Surprisingly, patterns of genetic variation, clades age and historical gene flow in populations distributed within the limits of the Last Glacial Maximum (LGM) are not explained by recent colonization. We propose an “intra-Andean multiple refuge” hypothesis, along with the classical refuge hypothesis previously proposed for the biota of the Chilean Coastal range and Eastern Andean Cordillera. Our hypothesis is supported by niche modelling analysis suggesting the persistence of fragments of suitable habitat for the species within the limits of the LGM ice shield. This type of refuge hypothesis is proposed for the first time for an ectothermic species.     

Biogeographic barriers in south‐eastern Australia drive phylogeographic divergence in the garden skink,Lampropholis guichenoti

Aim To investigate the impact of climatic oscillations and recognized biogeographic barriers on the evolutionary history of the garden skink (Lampropholis guichenoti), a common and widespread vertebrate in south‐eastern Australia. Location South‐eastern Australia. Methods Sequence data were obtained from the ND4 mitochondrial gene for 123 individuals from 64 populations across the entire distribution of the garden skink. A range of phylogenetic (maximum likelihood, Bayesian) and phylogeographic analyses (genetic diversity, Tajima’s D, Φ_ST, mismatch distribution) were conducted to examine the evolutionary history and diversification of the garden skink. Results A deep phylogeographic break (c. 14%), estimated to have occurred in the mid–late Miocene, was found between ‘northern’ and ‘southern’ populations across the Hunter Valley in northern New South Wales. Divergences among the geographically structured clades within the ‘northern’ (five clades) and ‘southern’ (seven clades) lineages occurred during the Pliocene, with the location of the major breaks corresponding to the recognized biogeographic barriers in south‐eastern Australia. Main conclusions Climatic fluctuations and the presence of several elevational and habitat barriers in south‐eastern Australia appear to be responsible for the diversification of the garden skink over the last 10 Myr. Further molecular and morphological work will be required to determine whether the two genetic lineages represent distinct species.     

Phylogeography of the widespread African puff adder (Bitis arietans) reveals multiple Pleistocene refugia in southern Africa

Evidence from numerous Pan‐African savannah mammals indicates that open‐habitat refugia existed in Africa during the Pleistocene, isolated by expanding tropical forests during warm and humid interglacial periods. However, comparative data from other taxonomic groups are currently lacking. We present a phylogeographic investigation of the African puff adder (Bitis arietans), a snake that occurs in open‐habitat formations throughout sub‐Saharan Africa. Multiple parapatric mitochondrial clades occur across the current distribution of B. arietans, including a widespread southern African clade that is subdivided into four separate clades. We investigated the historical processes responsible for generating these phylogeographic patterns in southern Africa using species distribution modelling and genetic approaches. Our results show that interior regions of South Africa became largely inhospitable for B. arietans during glacial maxima, whereas coastal and more northerly areas remained habitable. This corresponds well with the locations of refugia inferred from mitochondrial data using a continuous phylogeographic diffusion model. Analysis of data from five anonymous nuclear loci revealed broadly similar patterns to mtDNA. Secondary admixture was detected between previously isolated refugial populations. In some cases, this is limited to individuals occurring near mitochondrial clade contact zones, but in other cases, more extensive admixture is evident. Overall, our study reveals a complex history of refugial isolation and secondary expansion for puff adders and a mosaic of isolated refugia in southern Africa. We also identify key differences between the processes that drove isolation in B. arietans and those hypothesized for sympatric savannah mammals.     

Cranial morphological variation of Dromiciops gliroides (Microbiotheria) along its geographical distribution in south-central Chile: A three-dimensional analysis

We analyzed the variation in cranial morphology of the marsupial Dromiciops gliroides along its distribution in south-central Chile. We evaluated whether the cranial morphological variation is congruent with the phylogeographic structure previously observed in this species. We built three-dimensional models of 69 crania on which we digitized 30 landmarks. We used standard geometric morphometric methods to extract and analyze the shape and size components of the crania. Our data showed a subtle but consistent cranial size and shape variation along the studied distributional range, suggesting a geographic variation pattern rather than a phylogeographic structuring. Indeed, our multivariate analyses recovered a subtle morphological differentiation between island and mainland populations, contrary to what is suggested by a former phylogeographic study. We detected that either the cranial size variation, as well as the insularity and the latitude could be important factors underlying the cranial shape changes. We suggest that an interplay of historical and contemporary processes could be shaping the morphological pattern observed in this marsupial.     

Systematics and biogeography of the dobsonfly genus Nevromus Rambur (Megaloptera: Corydalidae: Corydalinae) from the Oriental realm

The Asian endemic dobsonfly genus Nevromus Rambur is revised. Six species of Nevromus are described or re‐described, and illustrated. Nevromus aspoeck Liu, Hayashi & Yang sp.n. , Nevromus austroindicus Liu & Viraktamath sp.n. and Nevromus gloriosoi Liu, Hayashi & Yang sp.n. are described from southernmost Yunnan of China and northern Thailand, southern India, and Borneo, respectively. A new combination Nevromus intimus (McLachlan) comb.n. is also identified. An interspecific phylogeny of Nevromus is reconstructed based on the adult morphological data, resulting in identification/recognition of two main clades, i.e. the mainland clade and the insular clade. Combining this phylogeny and the updated geographical distribution, an Indian origin and a historically widespread distribution in southern Eurasia is proposed for Nevromus. The deep divergence between the mainland and insular clades within Nevromus might have happened during the separation of Sundaland from Eurasia. The Tertiary orogenic events after the collision between the Indian subcontinent and Eurasia probably affected the speciation within the mainland clade of Nevromus, whereas the island formation of Borneo, Java and Sumatra shaped the fauna within the insular clade of this genus. The biogeographical pattern of Nevromus revealed in this study appears to have more general significance for understanding the faunal origin and diversification of the habitat‐specific or poorly dispersing insects from the Oriental realm.     

Phylogenetic divergence in leatherside chub (Gila copei) inferred from mitochondrial cytochrome b sequences

We examined intra-specific phylogenetic relationships in leatherside chub, Gila copei. The complete mitochondrial (mt) cytochrome b gene (1140 bp) was sequenced for 30 individuals from 10 populations that span the geographical distribution of this species. Traditional phylogenetic analyses revealed two deeply divergent and evolutionarily distinct mtDNA clades that are geographically separated in northern and southern drainage basins. Interpopulation sequence variation between clades ranged from 7.7 to 8.1%. The northern clade was genetically more similar and phylogenetically more closely related to the selected out-group Lepidomeda m. mollispinus than to the southern clade, suggesting that the taxonomy of this species may require revision. Sequence variation among populations within clades ranged from 0 to 0.3% in the north and from 0 to 0.7% in the south. Statistical parsimony was used to construct phylogenetic networks of haplotypes within clades. Nested clade analysis revealed that geographical fragmentation has played an important role in genetic structuring within northern and southern clades.