Isolation and characterization of nuclear microsatellite loci in the tropical arboreal palm Oenocarpus bacaba (Arecaceae)

Studies of mating patterns are needed to determine how habitat heterogeneity created by deforestation influences tropical plant populations. Eight microsatellite loci were isolated with a subtractive hybridization method for Oenocarpus bacaba (Arecaceae), a subcanopy palm tree at the Biological Dynamics of Forest Fragments Project, near Manaus, Brazil. Additionally, two heterospecific loci originally developed for the heart palm Euterpe edulis were shown to be variable. Loci averaged 9.6 alleles per locus. Five loci did not fit Hardy–Weinberg expectations with significant deficits of heterozygous genotypes consistent with null alleles. Many loci had high average probabilities of paternity exclusion.     

The relative contributions of seed and pollen dispersal to gene flow and genetic diversity in seedlings of a tropical palm

Seed and pollen dispersal shape patterns of gene flow and genetic diversity in plants. Pollen is generally thought to travel longer distances than seeds, but seeds determine the ultimate location of gametes. Resolving how interactions between these two dispersal processes shape microevolutionary processes is a long‐standing research priority. We unambiguously isolated the separate and combined contributions of these two dispersal processes in seedlings of the animal‐dispersed palm Oenocarpus bataua to address two questions. First, what is the spatial extent of pollen versus seed movement in a system characterized by long‐distance seed dispersal? Second, how does seed dispersal mediate seedling genetic diversity? Despite evidence of frequent long‐distance seed dispersal, we found that pollen moves much further than seeds. Nonetheless, seed dispersal ultimately mediates genetic diversity and fine‐scale spatial genetic structure. Compared to undispersed seedlings, seedlings dispersed by vertebrates were characterized by higher female gametic and diploid seedling diversity and weaker fine‐scale spatial genetic structure for female gametes, male gametes and diploid seedlings. Interestingly, the diversity of maternal seed sources at seed deposition sites (N _em) was associated with higher effective number of pollen sources (N _ep), higher effective number of parents (N _e) and weaker spatial genetic structure, whereas seed dispersal distance had little impact on these or other parameters we measured. These findings highlight the importance maternal seed source diversity (N _em) at frugivore seed deposition sites in driving emergent patterns of fine‐scale genetic diversity and structure.     

Spatial population genetic structure in Trillium grandiflorum: the roles of dispersal, mating, history, and selection

The roles of the various potential ecological and evolutionary causes of spatial population genetic structure (SPGS) cannot in general be inferred from the extant structure alone. However, a stage-specific analysis can provide clues as to the causes of SPGS. We conducted a stage-specific SPGS analysis of a mapped population of about 2000 Trillium grandiflorum (Liliaceae), a long-lived perennial herb. We compared SPGS for juvenile (J), nonreproductive (NR), and reproductive (R) stages. Fisher's exact test showed that genotypes had Hardy-Weinberg frequencies at all loci and stage classes. Allele frequencies did not differ between stages. Bootstrapped 99% confidence intervals (99%CI) indicate that F-statistic values are indistinguishable from zero, (except for a slightly negative FIT for the R stage). Spatial autocorrelation was used to calculate f the average kinship coefficient between individuals within distance intervals. Null hypothesis 99%CIs for f were constructed by repeatedly randomizing genotypic locations. Significant positive fine-scale genetic structure was detected in the R and NR stages, but not in the J stage. This structure was most pronounced in the R stage, and declined by about half in each remaining stage: near-neighbor f = 0.122, 0.065, 0.027, for R, NR, and J, respectively. For R and NR, the near-neighbor f lies outside the null hypothesis 99%CI, indicating kinship at approximately the level of half-sibs and first cousins, respectively. We also simulated the expected SPGS of juveniles post dispersal, based on measured R-stage SPGS, the mating system, and measured pollen and seed dispersal properties. This provides a null hypothesis expectation (as a 99%CI) for the J-stage correlogram, against which to test the likelihood that post-dispersal events have influenced J-stage SPGS. The actual J correlogram lies within the null hypothesis 99%CI for the shortest distance interval and nearly all other distance intervals indicating that the observed low recruitment, random mating and seed dispersal patterns are sufficient to account for the disappearance of SPSG between the R and the J stages. The observed increase in SPGS between J and R stages has two potential explanations: history and local selection. The observed low total allelic diversity is consistent with a past bottleneck: a possible historical explanation. Only a longitudinal stage-specific study of SPGS structure can distinguish between historical events and local selection as causes of increased structure with increasing life history stage.     

Genetic structure of the date palm (Phoenix dactylifera) in the Old World reveals a strong differentiation between eastern and western populations

Background and Aims Date palms (Phoenix dactylifera, Arecaceae) are of great economic and ecological value to the oasis agriculture of arid and semi-arid areas. However, despite the availability of a large date palm germplasm spreading from the Atlantic shores to Southern Asia, improvement of the species is being hampered by a lack of information on global genetic diversity and population structure. In order to contribute to the varietal improvement of date palms and to provide new insights on the influence of geographic origins and human activity on the genetic structure of the date palm, this study analysed the diversity of the species.Methods Genetic diversity levels and population genetic structure were investigated through the genotyping of a collection of 295 date palm accessions ranging from Mauritania to Pakistan using a set of 18 simple sequence repeat (SSR) markers and a plastid minisatellite.Key Results Using a Bayesian clustering approach, the date palm genotypes can be structured into two different gene pools: the first, termed the Eastern pool, consists of accessions from Asia and Djibouti, whilst the second, termed the Western pool, consists of accessions from Africa. These results confirm the existence of two ancient gene pools that have contributed to the current date palm diversity. The presence of admixed genotypes is also noted, which points at gene flows between eastern and western origins, mostly from east to west, following a human-mediated diffusion of the species.Conclusions This study assesses the distribution and level of genetic diversity of accessible date palm resources, provides new insights on the geographic origins and genetic history of the cultivated component of this species, and confirms the existence of at least two domestication origins. Furthermore, the strong genetic structure clearly established here is a prerequisite for any breeding programme exploiting the effective polymorphism related to each gene pool.     

The role of individual variation in flowering and pollination in the reproductive success of a crepuscular buzz-pollinated plant

Background and AimsPlant individuals within a population differ in their phenology and interactions with pollinators. However, it is still unknown how individual differences affect the reproductive success of plants that have functionally specialized pollination systems. Here, we evaluated whether plant individual specialization in phenology (temporal specialization) and in pollination (pollinator specialization) affect the reproductive success of the crepuscular-bee-pollinated plant Trembleya laniflora (Melastomataceae).MethodsWe quantified flowering activity (amplitude, duration and overlap), plant–pollinator interactions (number of flowers visited by pollinators) and reproductive success (fruit set) of T. laniflora individuals from three distinct locations in rupestrian grasslands of southeastern Brazil. We estimated the degree of individual temporal specialization in flowering phenology and of individual specialization in plant–pollinator interactions, and tested their relationship with plant reproductive success.Key Results Trembleya laniflora presented overlapping flowering, a temporal generalization and specialized pollinator interactions. Flowering overlap among individuals and populations was higher than expected by chance but did not affect the individual interactions with pollinators and nor their reproductive success. In contrast, higher individual generalization in the interactions with pollinators was related to higher individual reproductive success.ConclusionsOur findings suggest that individual generalization in plant–pollinator interaction reduces the potential costs of specialization at the species level, ensuring reproductive success. Altogether, our results highlight the complexity of specialization/generalization of plant–pollinator interactions at distinct levels of organization, from individuals to populations, to species.     

Population history and gene dispersal inferred from spatial genetic structure of a Central African timber tree,Distemonanthus benthamianus (Caesalpinioideae)

African rainforests have undergone major distribution range shifts during the Quaternary, but few studies have investigated their impact on the genetic diversity of plant species and we lack knowledge on the extent of gene flow to predict how plant species can cope with such environmental changes. Analysis of the spatial genetic structure (SGS) of a species is an effective method to determine major directions of the demographic history of its populations and to estimate the extent of gene dispersal. This study characterises the SGS of an African tropical timber tree species, Distemonanthus benthamianus, at various spatial scales in Cameroon and Gabon. Displaying a large continuous distribution in the Lower Guinea domain, this is a model species to detect signs of past population fragmentation and recolonization, and to estimate the extent of gene dispersal. Ten microsatellite loci were used to genotype 295 adult trees sampled from eight populations. Three clearly differentiated gene pools were resolved at this regional scale and could be linked to the biogeographical history of the region, rather than to physical barriers to gene flow. A comparison with the distribution of gene pools observed for two other tree species living in the same region invalidates the basic assumption that all species share the same Quaternary refuges and recolonization pathways. In four populations, significant and similar patterns of SGS were detected. Indirect estimates of gene dispersal distances (sigma) obtained for three populations ranged from 400 to 1200 m, whereas neighbourhood size estimates ranged from 50 to 110.     

The sandfly fauna (Diptera: Psychodidae: Phlebotominae) of the Parque Estadual da Serra da Tiririca,Rio de Janeiro, Brazil

Cutaneous leishmaniasis (CL) in the state of Rio de Janeiro is sporadic and canbe characterised as a peridomestic transmission that occurs in modified naturalenvironments. The aim of this work was to study the fauna and ecologicalcharacteristics of sandflies in an environmentally protected area (the StatePark of Serra da Tiririca) within the remnants of the Atlantic Forest in themunicipalities of Niterói and Maricá and their possible relationship withleishmaniasis. Captures were performed using light traps during the night once amonth for one year in both sylvatic environments and areas surrounding homesnear the park. A total of 1,037 sandflies were captured, belonging to ninegenera and 12 species: Evandromyia tupynambai (34.1%),Migonemyia migonei (20.6%), Brumptomyiacunhai (13.8%), Micropygomyia schreiberi (9.7%),Psathyromyia lanei (6.5%), Brumptomyianitzulescui (5.7%), Evandromyia edwardsi(5.4%), Nyssomyia intermedia (2.8%), Evandromyiacortelezzii (0.6%), Pintomyia bianchigalatiae(0.5%), Lutzomyia longipalpis (0.2%) and Sciopemyiamicrops (0.1%). Both Mg. migonei and Ny.intermedia may be acting as vectors of CL in this area.     

Cytogenetic variation of repetitive DNA elements in Hoplias malabaricus (Characiformes - Erythrinidae) from white,black and clear water rivers of the Amazon basin

Hoplias malabaricus is a common fish species occurring in white, black and clear water rivers of the Amazon basin. Its large distribution across distinct aquatic environments can pose stressful conditions for dispersal and creates possibilities for the emergence of local adaptive profiles. We investigated the chromosomal localization of repetitive DNA markers (constitutive heterochromatin, rDNA and the transposable element REX-3) in populations from the Amazonas river (white water), the Negro river (black water) and the Tapajós river (clear water), in order to address the variation/association of cytogenomic features and environmental conditions. We found a conserved karyotypic macrostructure with a diploid number of 40 chromosomes (20 metacentrics + 20 submetacentrics) in all the samples. Heteromorphism in pair 14 was detected as evidence for the initial differentiation of an XX/XY system. Minor differences detected in the amount of repetitive DNA markers are interpreted as possible signatures of local adaptations to distinct aquatic environments.     

The use of islands and cluster-randomized trials to investigate vector control interventions: a case study on the Bijagós archipelago,Guinea-Bissau

Vector-borne diseases threaten the health of populations around the world. While key interventions continue to provide protection from vectors, there remains a need to develop and test new vector control tools. Cluster-randomized trials, in which the intervention or control is randomly allocated to clusters, are commonly selected for such evaluations, but their design must carefully consider cluster size and cluster separation, as well as the movement of people and vectors, to ensure sufficient statistical power and avoid contamination of results. Island settings present an opportunity to conduct these studies. Here, we explore the benefits and challenges of conducting intervention studies on islands and introduce the Bijagós archipelago of Guinea-Bissau as a potential study site for interventions intended to control vector-borne diseases.This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases''.     

The interplay of dispersal limitation,rivers, and historical events shapes the genetic structure of an Amazonian frog

Disentangling the impact of landscape features such as rivers and historical events on dispersal is a challenging but necessary task to gain a comprehensive picture of the evolution of diverse biota such as that found in Amazonia. Adenomera andreae, a small, territorial, terrestrial frog species of the Amazonian forest represents a good model for such studies. We combined cytochrome b sequences with 12 microsatellites to investigate the genetic structure at two contrasted spatial scales in French Guiana: along a ～6‐km transect, to evaluate dispersal ability, and between paired bank populations along a ～65‐km stretch of the Approuague river, to test the effect of rivers as barriers to dispersal. We observed significant spatial genetic structure between individuals at a remarkably small geographical scale, and conclude that the species has a restricted dispersal ability that is probably tied to its life‐history traits. Mitochondrial and microsatellite data also indicate a high level of differentiation among populations on opposite banks of the river, and, in some cases, among populations on the same riverbank. These results suggest that the observed population structure in A. andreae is the result of restricted dispersal abilities combined with the action of rivers and Quaternary population isolation. Given that Amazonia hosts a great portion of anurans, as well as other small vertebrates, that display life‐history traits comparable with A. andreae, we argue that our analyses provide new insights into the complex interactions among evolutionary processes shaping Amazonian biodiversity. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 356–373.     

Low levels of realized seed and pollen gene flow and strong spatial genetic structure in a small,isolated and fragmented population of the tropical tree Copaifera langsdorffii Desf

Over the past century, the Brazilian Atlantic forest has been reduced to small, isolated fragments of forest. Reproductive isolation theories predict a loss of genetic diversity and increases in inbreeding and spatial genetic structure (SGS) in such populations. We analysed eight microsatellite loci to investigate the pollen and seed dispersal patterns, genetic diversity, inbreeding and SGS of the tropical tree Copaifera langsdorffii in a small (4.8 ha), isolated population. All 112 adult trees and 128 seedlings found in the stand were sampled, mapped and genotyped. Seedlings had significantly lower levels of genetic diversity (A=16.5±0.45, mean±95% s.e.; H_e=0.838±0.006) than did adult trees (A=23.2±0.81; H_e=0.893±0.030). Parentage analysis did not indicate any seed immigration (m_seeds=0) and the pollen immigration rate was very low (m_pollen=0.047). The average distance of realized pollen dispersal within the stand was 94 m, with 81% of the pollen travelling <150 m. A significant negative correlation was found between the frequency and distance of pollen dispersal (r=−0.79, P<0.01), indicating that short-distance pollinations were more frequent. A significant SGS for both adults (∼50 m) and seedlings (∼20 m) was also found, indicating that most of the seeds were dispersed over short distances. The results suggested that the spatial isolation of populations by habitat fragmentation can restrict seed and pollen gene flow, increase SGS and affect the genetic diversity of future generations.     

Contemporary gene flow and mating system of Arabis alpina in a Central European alpine landscape

Background and Aims

Gene flow is important in counteracting the divergence of populations but also in spreading genes among populations. However, contemporary gene flow is not well understood across alpine landscapes. The aim of this study was to estimate contemporary gene flow through pollen and to examine the realized mating system in the alpine perennial plant, Arabis alpina (Brassicaceae).

Methods

An entire sub-alpine to alpine landscape of 2 km² was exhaustively sampled in the Swiss Alps. Eighteen nuclear microsatellite loci were used to genotype 595 individuals and 499 offspring from 49 maternal plants. Contemporary gene flow by pollen was estimated from paternity analysis, matching the genotypes of maternal plants and offspring to the pool of likely father plants. Realized mating patterns and genetic structure were also estimated.

Key Results

Paternity analysis revealed several long-distance gene flow events (≤1 km). However, most outcrossing pollen was dispersed close to the mother plants, and 84 % of all offspring were selfed. Individuals that were spatially close were more related than by chance and were also more likely to be connected by pollen dispersal.

Conclusions

In the alpine landscape studied, genetic structure occurred on small spatial scales as expected for alpine plants. However, gene flow also covered large distances. This makes it plausible for alpine plants to spread beneficial alleles at least via pollen across landscapes at a short time scale. Thus, gene flow potentially facilitates rapid adaptation in A. alpina likely to be required under ongoing climate change.     

Low genetic variability, female-biased dispersal and high movement rates in an urban population of Eurasian badgers Meles meles

1. Urban and rural populations of animals can differ in their behaviour, both in order to meet their ecological requirements and due to the constraints imposed by different environments. The study of urban populations can therefore offer useful insights into the behavioural flexibility of a species as a whole, as well as indicating how the species in question adapts to a specifically urban environment. 2. The genetic structure of a population can provide information about social structure and movement patterns that is difficult to obtain by other means. Using non-invasively collected hair samples, we estimated the population size of Eurasian badgers Meles meles in the city of Brighton, England, and calculated population-specific parameters of genetic variability and sex-specific rates of outbreeding and dispersal. 3. Population density was high in the context of badger densities reported throughout their range. This was due to a high density of social groups rather than large numbers of individuals per group. 4. The allelic richness of the population was low compared with other British populations. However, the rate of extra-group paternity and the relatively frequent (mainly temporary) intergroup movements suggest that, on a local scale, the population was outbred. Although members of both sexes visited other groups, there was a trend for more females to make intergroup movements. 5. The results reveal that urban badgers can achieve high densities and suggest that while some population parameters are similar between urban and rural populations, the frequency of intergroup movements is higher among urban badgers. In a wider context, these results demonstrate the ability of non-invasive genetic sampling to provide information about the population density, social structure and behaviour of urban wildlife.     

The impact of mating systems and dispersal on fine‐scale genetic structure at maternally,paternally and biparentally inherited markers

For decades, studies have focused on how dispersal and mating systems influence genetic structure across populations or social groups. However, we still lack a thorough understanding of how these processes and their interaction shape spatial genetic patterns over a finer scale (tens—hundreds of metres). Using uniparentally inherited markers may help answer these questions, yet their potential has not been fully explored. Here, we use individual‐level simulations to investigate the effects of dispersal and mating system on fine‐scale genetic structure at autosomal, mitochondrial and Y chromosome markers. Using genetic spatial autocorrelation analysis, we found that dispersal was the major driver of fine‐scale genetic structure across maternally, paternally and biparentally inherited markers. However, when dispersal was restricted (mean distance = 100 m), variation in mating behaviour created strong differences in the comparative level of structure detected at maternally and paternally inherited markers. Promiscuity reduced spatial genetic structure at Y chromosome loci (relative to monogamy), whereas structure increased under polygyny. In contrast, mitochondrial and autosomal markers were robust to differences in the specific mating system, although genetic structure increased across all markers when reproductive success was skewed towards fewer individuals. Comparing males and females at Y chromosome vs. mitochondrial markers, respectively, revealed that some mating systems can generate similar patterns to those expected under sex‐biased dispersal. This demonstrates the need for caution when inferring ecological and behavioural processes from genetic results. Comparing patterns between the sexes, across a range of marker types, may help us tease apart the processes shaping fine‐scale genetic structure.     

Spatial vs. temporal effects on demographic and genetic structures: the roles of dispersal, masting and differential mortality on patterns of recruitment in Fagus sylvatica

Trees' long lifespan, long-distance dispersal abilities and high year-to-year variability in fecundity are thought to have pervasive consequences for the demographic and genetic structure of recruited seedlings. However, we still lack experimental studies quantifying the respective roles of spatial processes such as restricted seed and pollen dispersal and temporal processes such as mast seeding on patterns of regeneration. Dynamics of European beech (Fagus sylvatica) seedling recruitment was monitored in three plots from 2004 to 2006. Six polymorphic microsatellite genetic markers were used to characterize seedlings and their potential parents in a 7.2-ha stand. These seedlings were shown to result from 12 years of recruitment, with one predominant year of seedling recruitment in 2002 and several years without significant recruitment. Using a spatially explicit mating model based on parentage assignment, short average dispersal distances for seed (δ(s) = 10.9 m) and pollen (43.7 m < δ(p) <57.3 m) were found, but there was also a non-negligible immigration rate from outside the plot (m(s) = 20.5%; 71.6% < m(p) < 77.9%). Hierarchical analyses of seedling genetic structure showed that (i) most of the genetic variation was within plots; (ii) the genetic differentiation among seedling plots was significant (F(ST) = 2.6%) while (iii) there was no effect of year-to-year seed rain variation on genetic structure. In addition, no significant effect of genetic structure on mortality was detected. The consequences of these results for the prediction of population dynamics at ecological timescales are discussed.     

弄岗北热带喀斯特季节性雨林15 ha监测样地的树种组成与空间分布

北热带喀斯特季节性雨林(northern tropical karst seasonal rain forest)是在我国热带北缘喀斯特地区分布的典型森林植被类型之一。由于富钙偏碱的地球化学背景及多样性的生境类型, 同时受季风气候影响, 该森林呈现群落结构多样、树种组成丰富、特有成分突出等特点。基于大型固定监测样地对该森林树种组成与空间分布进行的研究, 是探明该区域生物多样性形成与维持机制的基础。我们于2011年底建立了广西弄岗北热带喀斯特季节性雨林15 ha监测样地, 依照CTFS (Center for Tropical Forest Science)全球森林生物多样性监测规范, 定位并调查了样地内每一棵胸径≥1 cm的木本植物。结果表明: (1)样地内有监测树种223种, 隶属于56科157属; 独立个体总数为68,010株(含分枝为95,471株), 平均胸径为4.84 cm; (2)树种科、属的区系均以热带成分为主, 大戟科、马鞭草科、梧桐科等为优势科; (3)个体数最多的11个树种的个体数之和占到总个体数的51.64%, 前58个树种的占90.19%; 稀有种有75种, 占总树种数的33.63%; (4)群落结构稳定且更新良好, 主要优势种的径级结构均呈倒“J”形, 无明显断层; (5)树种分布在空间上表现出明显差异, 黄梨木(Boniodendron minus)等强耐旱型树种分布于山顶周围; 蚬木(Excentrodendron tonkinense)等树种分布于山坡中部; 对叶榕(Ficus hispida)等喜湿耐荫型树种分布于山谷周围; (6)胸径>20 cm的个体较多分布在山坡中下部, 极少分布在山顶周围; 胸径10–20 cm的个体较均匀分布于整个样地; 分枝和萌枝较多分布在山顶周围; (7)种–面积散点图在2–7 ha的取样面积下分化形成两条曲线, 表明了树种数量组成在空间上具有强烈异质性。研究初步认为: 强烈生境异质性及独特地质背景可能是影响该喀斯特森林物种组成及空间分布的重要因素。     

The role of ecology,neutral processes and antagonistic coevolution in an apparent sexual arms race

Some of the strongest examples of a sexual ‘arms race’ come from observations of correlated evolution in sexually antagonistic traits among populations. However, it remains unclear whether these cases truly represent sexually antagonistic coevolution; alternatively, ecological or neutral processes might also drive correlated evolution. To investigate these alternatives, we evaluated the contributions of intersex genetic correlations, ecological context, neutral genetic divergence and sexual coevolution in the correlated evolution of antagonistic traits among populations of Gerris incognitus water striders. We could not detect intersex genetic correlations for these sexually antagonistic traits. Ecological variation was related to population variation in the key female antagonistic trait (spine length, a defence against males), as well as body size. Nevertheless, population covariation between sexually antagonistic traits remained substantial and significant even after accounting for all of these processes. Our results therefore provide strong evidence for a contemporary sexual arms race.     

Systematics of the Rhinella margaritifera complex (Anura,Bufonidae) from western Ecuador and Panama with insights in the biogeography of Rhinella alata

The Rhinella margaritifera species group consists of 17 species of toads distributed in tropical and subtropical South America and eastern Central America. The identity of some of its species is poorly understood and there are numerous undescribed cryptic species. Among them, the status of Rhinella margaritifera is one of the most problematic. Its range includes lowland rainforests separated by the Andes, the Chocoan rainforest to the west and the Amazonian rainforest to the east. This distribution is puzzling because the Andes are an old and formidable barrier to gene flow and therefore should generate vicariant speciation between disjunct lowland populations. Herein we clarify the taxonomy of populations of the Rhinella margaritifera complex from Central America and the Chocó region of South America. The morphological and genetic variation of Rhinella margaritifera was examined from 39 populations from Chocó, 24 from the upper Amazon region of Ecuador, and 37 from Panama, including the holotype of the Panamanian Rhinella alata. Phylogenetic analyses were performed based on mitochondrial genes 12S rRNA, 16S rRNA, and cytochrome c oxidase I (COI) and the nuclear gene Tyrosinase (Tyr). The genetic and morphological data show that Panamanian and Chocoan populations are conspecific. In the phylogeny, populations from Chocó and Panama form a well-supported clade. The morphology of the holotype of Rhinella alata falls within the variation range of Panamanian and Chocoan populations. Based on all this evidence, we assign the populations from western Ecuador and Panama to Rhinella alata and demonstrate that the unusual distribution pattern of “Rhinella margaritifera” on both sides of the Andes was an artifact of incorrectly defined species boundaries.