Intraspecific Morphological Variation Research Articles

Sexual dimorphism and intraspecific variation in wing size and shape ofTongeia fischeri(Lepidoptera: Lycaenidae)

AbstractWing morphological variations are described here for the lycaenid butterfly Tongeia fischeri. A landmark‐based geometric morphometric approach based on wing venation of 197 male and 187 female butterflies collected in Japan was used to quantify wing size and shape variations between sexes and among populations. Sexual dimorphism in wing size and shape was detected. Females had significantly larger wings than males, while males showed a relatively elongated forewing with a longer apex and narrower wing tornus in comparison to females. Intraspecific variations in wing morphology among populations were revealed for the wing shape, but not wing size. Distinct wing shape differences were found in the vein intersections area around the distal part of the discal cell where median veins originated in the forewing and around the origin of the CU1 vein in the hindwing. In addition, phenotypic relationships inferred from wing shape variations grouped T. fischeri populations into three groups, reflecting the subspecies classification of the species. The spatial variability and phenotypic relationships between conspecific populations of T. fischeri detected here are generally in agreement with the previous molecular study based on mitochondrial and nuclear sequences, suggesting the presence of a phylogenetic signal in the wing shape of T. fischeri, and thus having taxonomic implications.

Complex geographical variation patterns in Tropheus duboisi Marlier, 1959 (Perciformes, Cichlidae) from Lake Tanganyika

Intra-specific morphological variation in the cichlid Tropheus duboisi from 10 localities over its entire known distribution area along the central eastern and northern shore of Lake Tanganyika was investigated. This revealed significant differences between various populations that are geographically isolated. These morphological observations only partially correspond to the results of a haplotype network, based on mtDNA. In addition, a difference in the timing of the onset of the adult colour pattern was discovered for one isolated population. The occurrence of morphological intra-specific differentiation is discussed with respect to the basal position of T. duboisi within Tropheus as well as to the presumed morphological stasis of the genus.

Inter- and intraspecific morphological variation of four-shelled Actinomma taxa (Radiolaria) in polar and subpolar regions

The taxonomy of polycystine radiolarians is important for biostratigraphic, paleoecological and paleoceanographical reconstructions. In this study we describe four morphogroups of Actinomma boreale from the North-Atlantic and Arctic oceans. We distinguish them from two other four-shelled Actinomma species from the Southern Ocean and North Pacific, namely Sphaeropyle langii and Prunopyle antarctica, which are both moved to the genus Actinomma. As Actinomma antarcticum is an already occupied name, P. antarctica is renamed as Actinomma friedrichdreyeri nomen novum. Quantitative and qualitative intraspecific morphological variation was studied by examining 922 specimens (8599 photographs) from 49 samples, of which 45 are from the surface sediment, two are from deeper sediments, and two are plankton samples. We found significant differences in shell diameters between North Atlantic and Arctic Atlantic samples, and between recent and downcore samples within A. boreale. We also found significant differences between populations of A. friedrichdreyeri and A. langii from the Southern Ocean versus the North Pacific. We do not recommend the naming of extant polycystine radiolarian species based on continuous characters without supporting phylogenetic information. Therefore, with this study we have provided directions for phylogenetic investigations on A. boreale, A. friedrichdreyeri and A. langii.

Facultative paedomorphosis and the pattern of intra- and interspecific variation in cranial skeleton: lessons from European newts (Ichthyosaura alpestris and Lissotriton vulgaris)

Paedomorphosis, the presence of ancestral larval and juvenile traits that occur at the descendent adult stage, is an evolutionary phenomenon that shaped morphological evolution in many vertebrate lineages, including tailed amphibians. Among salamandrid species, paedomorphic and metamorphic phenotypes can be observed within single populations (facultative paedomorphosis). Despite wide interest in facultative paedomorphosis and polymorphism produced by heterochronic changes (heterochronic polymorphism), the studies that investigate intraspecific morphological variation in facultative paedomorphic species are largely missing. By quantifying the cranium size and development (bone development and remodeling), we investigated the variation at multiple levels (i.e., between sexes, populations and species) of two facultatively paedomorphic European newt species: the alpine and the smooth newt. The pattern of variation between paedomorphs (individuals keeping larval traits at the adult stage) and metamorphs (metamorphosed adult individuals) varied between species and among populations within a single species. The patterns of variation in size and skull formation appear to be more uniform in the alpine than in the smooth newt, indicating that developmental constraints differed between species (more pronounced in alpine than in smooth newt). Our study shows that the cranial skeleton provides detailed insight in the pattern of variation and divergence in heterochronic polymorphism within and between species and open new questions related to heterochronic polymorphism and evolution of cranial skeleton.

Barcoding Poplars (Populus L.) from Western China

Background Populus is an ecologically and economically important genus of trees, but distinguishing between wild species is relatively difficult due to extensive interspecific hybridization and introgression, and the high level of intraspecific morphological variation. The DNA barcoding approach is a potential solution to this problem.Methodology/Principal FindingsHere, we tested the discrimination power of five chloroplast barcodes and one nuclear barcode (ITS) among 95 trees that represent 21 Populus species from western China. Among all single barcode candidates, the discrimination power is highest for the nuclear ITS, progressively lower for chloroplast barcodes matK (M), trnG-psbK (G) and psbK-psbI (P), and trnH-psbA (H) and rbcL (R); the discrimination efficiency of the nuclear ITS (I) is also higher than any two-, three-, or even the five-locus combination of chloroplast barcodes. Among the five combinations of a single chloroplast barcode plus the nuclear ITS, H+I and P+I differentiated the highest and lowest portion of species, respectively. The highest discrimination rate for the barcodes or barcode combinations examined here is 55.0% (H+I), and usually discrimination failures occurred among species from sympatric or parapatric areas.Conclusions/SignificanceIn this case study, we showed that when discriminating Populus species from western China, the nuclear ITS region represents a more promising barcode than any maternally inherited chloroplast region or combination of chloroplast regions. Meanwhile, combining the ITS region with chloroplast regions may improve the barcoding success rate and assist in detecting recent interspecific hybridizations. Failure to discriminate among several groups of Populus species from sympatric or parapatric areas may have been the result of incomplete lineage sorting, frequent interspecific hybridizations and introgressions. We agree with a previous proposal for constructing a tiered barcoding system in plants, especially for taxonomic groups that have complex evolutionary histories (e.g. Populus).

A new synonymy of Graptocleptes bicolor (Burmeister), with taxonomical notes (Hemiptera: Heteroptera: Reduviidae: Harpactorinae: Harpactorini).

Hiranetis coleopteroides (Walker, 1873) is here found to be conspecific with Graptocleptes bicolor (Burmeister, 1838). Graptocleptes bicolor is redescribed and the male genitalia characters are illustrated for the first time. Intraspecific morphological, color and male genitalia variability are discussed. Furthermore, the species is recorded from Paraguay for the first time.

Intraspecific morphological and genetic variation of common species predicts ranges of threatened ones

Predicting where threatened species occur is useful for making informed conservation decisions. However, because they are usually rare, surveying threatened species is often expensive and time intensive. Here, we show how regions where common species exhibit high genetic and morphological divergence among populations can be used to predict the occurrence of species of conservation concern. Intraspecific variation of common species of birds, bats and frogs from Ecuador were found to be a significantly better predictor for the occurrence of threatened species than suites of environmental variables or the occurrence of amphibians and birds. Fully 93 per cent of the threatened species analysed had their range adequately represented by the geographical distribution of the morphological and genetic variation found in seven common species. Both higher numbers of threatened species and greater genetic and morphological variation of common species occurred along elevation gradients. Higher levels of intraspecific divergence may be the result of disruptive selection and/or introgression along gradients. We suggest that collecting data on genetic and morphological variation in common species can be a cost effective tool for conservation planning, and that future biodiversity inventories include surveying genetic and morphological data of common species whenever feasible.

A review of diagnostic imaging of snakes and lizards

Snakes and lizards are considered ‘stoic’ animals and often show only non-specific signs of illness. Consequently, diagnostic imaging – along with clinical examination and laboratory tests – is gaining importance...

Variation in Body Shape across Species and Populations in a Radiation of Diaptomid Copepods

Inter and intra-population variation in morphological traits, such as body size and shape, provides important insights into the ecological importance of individual natural populations. The radiation of Diaptomid species (~400 species) has apparently produced little morphological differentiation other than those in secondary sexual characteristics, suggesting sexual, rather than ecological, selection has driven speciation. This evolutionary history suggests that species, and conspecific populations, would be ecologically redundant but recent work found contrasting ecosystem effects among both species and populations. This study provides the first quantification of shape variation among species, populations, and/or sexes (beyond taxonomic illustrations and body size measurements) to gain insight into the ecological differentiation of Diaptomids. Here we quantify the shape of five Diaptomid species (family Diaptomidae) from four populations each, using morphometric landmarks on the prosome, urosome, and antennae. We partition morphological variation among species, populations, and sexes, and test for phenotype-by-environment correlations to reveal possible functional consequences of shape variation. We found that intraspecific variation was 18-35% as large as interspecific variation across all measured traits. Interspecific variation in body size and relative antennae length, the two traits showing significant sexual dimorphism, were correlated with lake size and geographic location suggesting some niche differentiation between species. Observed relationships between intraspecific morphological variation and the environment suggest that divergent selection in contrasting lakes might contribute to shape differences among local populations, but confirming this requires further analyses. Our results show that although Diaptomid species differ in their reproductive traits, they also differ in other morphological traits that might indicate ecological differences among species and populations.

Intraspecific morphological and genetic variation of common species predicts ranges of threatened ones

Predicting where threatened species occur is useful for making informed conservation decisions. However, because they are usually rare, surveying threatened species is often expensive and time intensive. Here, we show how regions where common species exhibit high genetic and morphological divergence among populations can be used to predict the occurrence of species of conservation concern. Intraspecific variation of common species of birds, bats and frogs from Ecuador were found to be a significantly better predictor for the occurrence of threatened species than suites of environmental variables or the occurrence of amphibians and birds. Fully 93 per cent of the threatened species analysed had their range adequately represented by the geographical distribution of the morphological and genetic variation found in seven common species. Both higher numbers of threatened species and greater genetic and morphological variation of common species occurred along elevation gradients. Higher levels of intraspecific divergence may be the result of disruptive selection and/or introgression along gradients. We suggest that collecting data on genetic and morphological variation in common species can be a cost effective tool for conservation planning, and that future biodiversity inventories include surveying genetic and morphological data of common species whenever feasible.

Review of the systematics, distribution, biogeography and natural history of Moroccan amphibians.

The amphibian fauna of the Kingdom of Morocco was traditionally regarded as poor and closely related to its European counterpart. However, an increase in research during the last decades revealed a considerable degree of endemism amongst Moroccan amphibians, as well as phenotypic and genotypic inter- and intraspecific divergence. Despite this increase in knowledge, a comprehensible overview is lacking while several systematic issues have remained unresolved. We herein present a contemporary overview of the distribution, taxonomy and biogeography of Moroccan amphibians. Fourteen fieldtrips were made by the authors and colleagues between 2000 and 2012, which produced a total of 292 new distribution records. Furthermore, based on the results of the present work, we (i) review the systematics of the genus Salamandra in Morocco, including the description of a new subspecies from the Rif- and Middle Atlas Mountains, Salamandra algira splendens ssp. nov.; (ii) present data on intraspecific morphological variability of Pelobates varaldiiand Pleurodeles waltl in Morocco; (iii) attempt to resolve the phylogenetic position of Bufo brongersmai and erect a new genus for this species, Barbarophryne gen. nov.; (iv) summarize and assess the availability of tadpole-specific characteristics and bioacoustical data, and (v) summarize natural history data.

Wave-induced abiotic stress shapes phenotypic diversity in a coral reef fish across a geographical cline

While morphological variation across geographical clines has been well documented, it is often unclear whether such changes enhance individual performance to local environments. We examined whether the damselfish Acanthochromis polyacanthus display functional changes in swimming phenotype across a 40-km cline in wave-driven water motion on the Great Barrier Reef, Australia. A. polyacanthus populations displayed strong intraspecific variation in swimming morphology and performance that matched local levels of water motion: individuals on reefs subject to high water motion displayed higher aspect-ratio fins and faster swimming speeds than conspecifics on sheltered reefs. Remarkably, intraspecific variation within A. polyacanthus spanned over half the diversity seen among closely related damselfish species from the same region. We find that local selection driven by wave-induced abiotic stress is an overarching ecological mechanism shaping the inter- and intraspecific locomotor diversity of coral reef fishes.

Testing Species Delimitations in Four Italian Sympatric Leuciscine Fishes in the Tiber River: A Combined Morphological and Molecular Approach

Leuciscine fishes represent an important component of freshwater ichthyofauna endemic to northern Mediterranean areas. This lineage shows high intra-specific morphological variability and exhibits high levels of hybridization, two characteristics that contribute to systematic uncertainties, misclassification of taxa and, potentially, the mismanagement of biodiversity. This study focused on brook chub, Squalius lucumonis, an endemic taxon of Central Italy. The taxonomic status of this species has long been questioned, and a hybrid origin from sympatric leusciscines (S. squalus x Rutilus rubilio, or S. squalus x Telestes muticellus) has been hypothesised. A phenotypic (evaluating shape and meristic counts) and genetic (using mitochondrial and nuclear markers) investigation of these four taxa was conducted to test species delimitation in sympatric areas and to evaluate the taxonomic status of S. lucumonis. One hundred and forty-five individuals of all four taxa were collected within streams of the lowest portion of the Tiber River basin and analysed; this region encompasses a large portion of the S. lucumonis distribution. The different morphological and genetic approaches were individually examined, compared, and then combined in a quantitative model to both investigate the limits of each approach and to identify cases of misclassification. The results obtained confirm the cladogenetic non-hybrid origin of S. lucumonis, highlight the need for immediate conservation actions and emphasise the value of an integrated approach in the study of leuciscines evolution.

Evidence of light-induced phenotypic plasticity in zoanthids: editorial comment on the feature article by Wei et al.

Phenotypic plasticity refers to the morphological variation of a single genotype across different environments (Kelly et al. 2012). The adaptive advantage of phenotypic plasticity includes the capacity for adjusting to variable environments across multiple habitats and over time as environments experience change. This ability has been documented in a range of benthic marine organisms, including corals (Hoeksema 2012). Like corals and anemones, zoanthids are anthozoans which often harbour symbiotic dinoflagellates (from the genus Symbiodinium). However, zoanthids have received considerably less attention compared to their cnidarian counterparts, with respect to their ecology. It is known that zoanthids exhibit high intraspecific morphological variability (Reimer et al. 2004), but it has been unclear whether this is due to polymorphism, phenotypic plasticity, or a combination of both. The study by Wei et al. (2013) presents the first evidence for phenotypic plasticity in zoanthids. Colonies of Zoanthus sansibaricus and Palythoa tuberculosa all displayed lightinduced changes in morphology. Based on reaction norms, principal components analysis, analysis of variance, and canonical discriminant analysis, the authors demonstrate morphological differences between shading treatments, but also between local populations and a population 9 treatment effect. Polyps of shaded colonies were generally larger and taller than those of unshaded colonies. Population 9 environment interactions show that populations of both species varied in the magnitude and direction of their morphologic responses to shading, suggesting some degree of acclimatization or local adaptation to natal reefs. Importantly, the authors have provided evidence that environmentally mediated changes can contribute to the morphological variation often described in zoanthids (Burnett et al. 1997). These morphologically plastic attributes may enable them to withstand temporal changes in their environment. In addition, given phenotypic plasticity is often associated with a generalist life strategy, these species of zoanthids may survive in spatially variable habitats (van Tienderen 1991). Therefore, this study not only clarifies the effect of illumination in zoanthids but also gives a more general insight on morphology in anthozoans that harbour symbiotic algae.

Molecular Analysis of the Freshwater Prawn Macrobrachium olfersii (Decapoda, Palaemonidae) Supports the Existence of a Single Species throughout Its Distribution

Macrobrachium olfersii is an amphidromous freshwater prawn, widespread along the eastern coasts of the Americas. This species shows great morphological modifications during ontogenesis, and several studies have verified the existence of a wide intraspecific variation. Because of this condition, the species is often misidentified, and several synonyms have been documented. To elucidate these aspects, individuals of M. olfersii from different populations along its range of distribution were investigated. The taxonomic limit was established, and the degree of genetic variability of this species was described. We extracted DNA from 53 specimens of M. olfersii, M. americanum, M. digueti and M. faustinum, which resulted in 84 new sequences (22 of 16S mtDNA, 45 of Cythocrome Oxidase I (COI) mtDNA, and 17 of Histone (H3) nDNA). Sequences of three genes (single and concatenated) from these species were used in the Maximum Likelihood and Bayesian Inference phylogenetic analyses and COI sequences from M. olfersii were used in population analysis. The genetic variation was evaluated through the alignment of 554 bp from the 16S, 638 bp from the COI, and 338 bp from the H3. The rates of genetic divergence among populations were lower at the intraspecific level. This was confirmed by the haplotype net, which showed a continuous gene flow among populations. Although a wide distribution and high morphological intraspecific variation often suggest the existence of more than one species, genetic similarity of Caribbean and Brazilian populations of M. olfersii supported them as a single species.

Biodiversity in wood-decay macro-fungi associated with declining arid zone trees of India as revealed by nuclear rDNA analysis

Wood-decay macro-fungi have been reported to be a major cause of decline of arid zone trees in the genera Acacia, Prosopis, Ziziphus and Azadirachta; the identity of these fungi, however, has not been confirmed in the state of Rajasthan in northwestern India. Direct sequencing of PCR amplified ITS regions of rDNA facilitated molecular identification of 26 isolates into species in eight genera (Ganoderma, Inonotus, Phellinus, Ceriporia, Schizophyllum, Phanerochaete, Pleurotus, Leucoagaricus) and one incompletely characterized Basidiomycota species. In addition to intra-specific phenotypic variations in basidiocarp morphology, Single Nucleotide Polymorphisms (SNPs) were recorded among isolates of P. pulmonarius, S. commune, G. lucidum and Ganoderma species. Both SNPs and insertions/deletions (INDELS) were recorded amongst Inonotus species. A phylogram based on multiple sequence alignment delineated all isolates into separate intra-specific subgroups along with their GenBank reference sequences with high bootstrap values. Phellinus repandus, L. meleagris, C. lacerata and three Inonotus species (I. rickii, I. patouillardii, and I. porrectus) reported herein are new fungal records from India.

Hidden diversity and cryptic speciation refute cosmopolitan distribution inCaprella penantis(Crustacea: Amphipoda: Caprellidae)

Caprella penantis is considered a cosmopolitan species and one of the most challenging caprellids in taxonomic terms because of its remarkable intraspecific morphological variation. This study examined DNA sequences from mitochondrial (COI) and nuclear (18S) markers together with morphological data from 25 localities of C. penantis, and closely related species Caprella dilatata and Caprella andreae, all traditionally considered part of the old ‘acutifrons’ complex. The large genetic divergence and reciprocally allopatric distributions point to the existence of a species complex of at least four species, of which one is reported as a cryptic species. This study provides the first evidence of cryptic speciation in the family Caprellidae, and questions the validity of some traditional morphological characters used to delimit species in the genus Caprella. Our results are consistent with the idea that main factors were probably isolation by distance and ecological traits, promoting diversification in C. penantis. The strong genetic structure reported for this species in the Iberian Peninsula and Moroccan coasts also suggests restriction to dispersal as well as the presence of refugial areas. These results highlight the utility of the COI and 18S genes in combination with morphological characters for shedding light on systematic questions in caprellids, and patterns of genetic connectivity.

The six-eyed sand spiders of the genus Sicarius (Araneae: Haplogynae: Sicariidae) from the Brazilian Caatinga

In this paper we revise the species of Sicarius (Araneae: Sicariidae) from the Brazilian Caatinga, the largest tropical dryforest nucleus in the world. We redescribe, designate a neotype and provide new records for Sicarius tropicus (Mello-Leitão, 1936), the only species previously known from the region, and describe three new species: S. cariri n. sp., S.diadorim n. sp. and S. ornatus n. sp. We report high intraspecific variation in the genitalic morphology of these species,especially in females. We also provide anecdotal observations on natural history and behavior of these species, includingdiet, mating behavior and clutch size. We include an identification key for Brazilian Caatinga species of Sicarius.

Variation in leaf morphology of the invasive cat's claw creeper Dolichandra unguis-cati (Bignoniaceae)

The invasive liana cat’s claw creeper Dolichandra unguis-cati (L.) L.G. Lohmann (syn. Macfadyena unguis-cati (L.) A.H. Gentry) exhibits intraspecific variation in leaf morphology, but this is rarely noted in the published literature. The present study documents variation in leaf morphology in two forms of the species that occur in Australia (long pod and short pod). Leaf morphology is compared between the two forms and the position of the shoots (trunk and ground) at the only two sites in which they co-occur. Leaves were categorised on the basis of leaflet number and the presence or absence of tendrils. Simple leaves were produced mainly on shoots growing along the ground and were more abundant in the short-pod form. Long-pod plants were dominated by bifoliate leaves with tendrils. Cat’s claw creeper exhibits considerably wider variation in leaf morphology than recorded previously. Variations in leaf morphology may be linked to differences in the genotype, developmental stage and plastic responses of the plants. Understanding these variations may have implications for taxonomic delimitation and improved management, particularly biological control involving leaf-feeding insects.

Intraspecific variability and genetic structure in Meloidogyne chitwoodi from the USA

Meloidogyne chitwoodi is a quarantine pathogen and a severe problem of potato. Intraspecific variation and genetic structure are not well characterised for M. chitwoodi, but are critical to avoid misidentification and to optimise management strategies. The objective of this study was to analyse the morphological and molecular variation of four M. chitwoodi isolates, representing all races and pathotypes currently known in the USA. Despite statistically significant morphological variation among adult females, morphometrics were not able reliably to distinguish M. chitwoodi isolates. In contrast to morphology, molecular traits that are determined by nuclear ribosomal genes were stable across all isolates. Malate dehydrogenase, esterase and superoxide dismutase isozyme phenotypes were conserved in all isolates, which is an important finding for diagnostics. To gain insight into the genetic structure of M. chitwoodi, we analysed a mitochondrial DNA segment including a partial region of COII, tRNA-His and 16S rRNA genes. Genetic structure was weak and marked by high haplotype and low nucleotide diversity. We found a high level of mitochondrial heteroplasmy in M. chitwoodi. Taken together, our results indicate that there is significant intraspecific morphological and molecular variation in M. chitwoodi. Consequences for resistance breeding in potato and directions for phylogeographic studies to trace the origin of M. chitwoodi are discussed.