Wide Intraspecific Variation Research Articles

Iterative taxonomy reveals a new species of Cambeva (Siluriformes: Trichomycteridae) with intraspecific variation from the rio Piquiri and Ivaí basin, upper rio Paraná basin, Brazil

Abstract A new species of Cambeva occurring in the rio Piquiri and Ivaí, upper rio Paraná basin, Brazil, is described using the combination of morphological and molecular data. The new species is distinguished from most congeners by the presence of a notch in the posterior portion of the metapterygoid, number of branchiostegal rays, opercular and interopercular odontodes, and ribs. In addition, the results corroborated the existence of a single species with wide intraspecific variation in body coloration. The type-locality is within the area of influence of the Perobas Biological Reserve, a Conservation Unit in the Paraná State, composed of two Atlantic Forest physiognomic forms. Considering that the upper rio Paraná basin is an area of significant anthropic influence, it is crucial to describe and preserve species to understand their ichthyofauna.

Taxonomic insights from floral scents of western North American sessile-flowered Trillium.

Chemical composition of floral volatiles can be an important complement to morphological characters in describing and identifying species. Four of the five species of western sessile-flowered Trillium are challenging to distinguish morphologically due to wide intraspecific variation and overlapping characters among taxa. Characterizing their floral volatile compositions could aid future taxonomic, ecological, and evolutionary studies of Trillium and related taxa. We addressed two major questions: How do western sessile Trillium taxa vary in floral chemistry? Can floral scent be used to distinguish species? We collected petals from 600 individuals at 42 wild populations of four sessile Trillium species across California, Oregon, and Washington. Volatile organic compounds from the petals were extracted using solid-phase microextraction, and the volatiles were identified and quantified by gas chromatography-mass spectrometry. The utility of floral scent composition in distinguishing species was tested using nonmetric multidimensional scaling and random forest analysis. Floral volatiles of the white-petaled T. albidum were dominated by oxygenated monoterpenes and showed considerable geographic variation that paralleled morphological variation. The maroon-petaled T. angustipetalum and T. kurabayashii produced floral scents characterized by aliphatic esters, but each had a distinct chemical composition. Petal color of Trillium chloropetalum is highly variable, as were its scent compositions, which were blends of volatiles from both white-petaled and maroon-petaled congeneric taxa. Differences in floral scent compositions are consistent with current taxonomy of the western sessile Trillium group. In cases where species delimitations are difficult based on morphology, floral scent composition provides taxonomic insight and suggests a potential hybrid origin for T. chloropetalum.

Mining Aegilops tauschii genetic diversity in the background of bread wheat revealed a novel QTL for seed dormancy.

Due to the low genetic diversity in the current wheat germplasm, gene mining from wild relatives is essential to develop new wheat cultivars that are more resilient to the changing climate. Aegilops tauschii, the D-genome donor of bread wheat, is a great gene source for wheat breeding; however, identifying suitable genes from Ae. tauschii is challenging due to the different morphology and the wide intra-specific variation within the species. In this study, we developed a platform for the systematic evaluation of Ae. tauschii traits in the background of the hexaploid wheat cultivar 'Norin 61' and thus for the identification of QTLs and genes. To validate our platform, we analyzed the seed dormancy trait that confers resistance to preharvest sprouting. We used a multiple synthetic derivative (MSD) population containing a genetic diversity of 43 Ae. tauschii accessions representing the full range of the species. Our results showed that only nine accessions in the population provided seed dormancy, and KU-2039 from Afghanistan had the highest level of seed dormancy. Therefore, 166 backcross inbred lines (BILs) were developed by crossing the synthetic wheat derived from KU-2039 with 'Norin 61' as the recurrent parent. The QTL mapping revealed one novel QTL, Qsd.alrc.5D, associated with dormancy explaining 41.7% of the phenotypic variation and other five unstable QTLs, two of which have already been reported. The Qsd.alrc.5D, identified for the first time within the natural variation of wheat, would be a valuable contribution to breeding after appropriate validation. The proposed platform that used the MSD population derived from the diverse Ae. tauschii gene pool and recombinant inbred lines proved to be a valuable platform for mining new and important QTLs or alleles, such as the novel seed dormancy QTL identified here. Likewise, such a platform harboring genetic diversity from wheat wild relatives could be a useful source for mining agronomically important traits, especially in the era of climate change and the narrow genetic diversity within the current wheat germplasm.

Introgression Underlies Phylogenetic Uncertainty But Not Parallel Plumage Evolution in a Recent Songbird Radiation.

Instances of parallel phenotypic evolution offer great opportunities to understand the evolutionary processes underlying phenotypic changes. However, confirming parallel phenotypic evolution and studying its causes requires a robust phylogenetic framework. One such example is the "black-and-white wagtails," a group of 5 species in the songbird genus Motacilla: 1 species, Motacilla alba, shows wide intra-specific plumage variation, while the 4r others form 2 pairs of very similar-looking species (M. aguimp + M. samveasnae and M. grandis + M. maderaspatensis, respectively). However, the 2 species in each of these pairs were not recovered as sisters in previous phylogenetic inferences. Their relationships varied depending on the markers used, suggesting that gene tree heterogeneity might have hampered accurate phylogenetic inference. Here, we use whole genome resequencing data to explore the phylogenetic relationships within this group, with a special emphasis on characterizing the extent of gene tree heterogeneity and its underlying causes. We first used multispecies coalescent methods to generate a "complete evidence" phylogenetic hypothesis based on genome-wide variants, while accounting for incomplete lineage sorting (ILS) and introgression. We then investigated the variation in phylogenetic signal across the genome to quantify the extent of discordance across genomic regions and test its underlying causes. We found that wagtail genomes are mosaics of regions supporting variable genealogies, because of ILS and inter-specific introgression. The most common topology across the genome, supporting M. alba and M. aguimp as sister species, appears to be influenced by ancient introgression. Additionally, we inferred another ancient introgression event, between M. alba and M. grandis. By combining results from multiple analyses, we propose a phylogenetic network for the black-and-white wagtails that confirms that similar phenotypes evolved in non-sister lineages, supporting parallel plumage evolution. Furthermore, the inferred reticulations do not connect species with similar plumage coloration, suggesting that introgression does not underlie parallel plumage evolution in this group. Our results demonstrate the importance of investing genome-wide patterns of gene tree heterogeneity to help understand the mechanisms underlying phenotypic evolution. [Gene tree heterogeneity; incomplete lineage sorting; introgression; parallel evolution; phylogenomics; plumage evolution; wagtails.].

Improvement of the description of ostracods of the family TRACHYLEBERIDINAE

Introduction. The definition of criteria for separating closely related species of representatives of the genus Cythereis is currently incomplete. Ostracods of this genus have wide intraspecific variability and high adaptability to changing living conditions. These factors make it difficult to use these ostracod species for regional stratigraphic correlation. In addition to the selection of criteria for species separation, there is a problem of the imperfection of the terminological apparatus for describing ostracods, which complicates the description of species and omits potentially important information for the separation of related species. Analysis of previous publications. Numerous works are devoted to the issue of the development of the terminological apparatus for describing ostracods, however, qualitative methods of description are inherent only to certain large taxa, where a separate method of description has been developed for each taxon. Ostracods of the genus Cythereis are widespread in the Cretaceous Tethys. Their wide variability is considered by various authors often without taking into account intraspecific variability and adaptation, which leads to the selection of subspecies or ignoring variability. Materials and methods. Numerous ostracods of the species Cythereis hirsuta Damotte&Grosdidier from the Late Cenomanian and Cythereis ornatissima (Reuss) from the Turonian of Ukraine were used in the work. Ostracods were selected from different deposits according to the conditions of origin. Results and discussion. The paper describes in detail the morphology of ostracods of the genus Cythereis with qualitative characteristics of morphological elements. The ontogenetic changes of the two species and the change in morphology depending on the conditions of existence are also described. The change in the morphology of juvenile forms depending on the conditions of existence is described separately. Conclusions. Based on the study and description of numerous paleontological materials, a number of refinements were proposed to the descriptive characteristics of the morphological elements of ostracod valves of members of the family TRACHYLEBERIDINAE Sylvester-Bradley, 1948 and the genus Cythereis in particular. The proposed clarifications regarding the morphology of the mesosculpture made it possible to describe in detail the ontogenetic changes of the studied species and their differences in adult stages depending on the facial conditions of existence. It should be noted that a detailed scheme for describing the morphology of mesosculpture is proposed for the first time in the literature. The paleontological description of numerous materials from the Middle Cretaceous of Ukraine allowed to establish the morphological elements that are of primary importance for the separation of related species within the genus. The analysis of these elements suggests that some of the similar species from the outcrops of Europe and Asia are actually other species. The question of their phylogenetic ties can be solved under the condition of studying ontogenesis and expanding the geography of research. Based on this, the validity of the names of the studied species from the territory of Ukraine is also contradictory to the actual comparison with the holotype collection.

The spermatheca in the genus Dendroctonus (Curculionidae: Scolytinae): morphology, nomenclature, potential characters for taxonomic use and phylogenetic signal

In most members of the genus Dendroctonus, the usefulness of the spermatheca for taxonomic purposes has not been evaluated in depth; therefore, the aim of this study is to describe and compare the elements that integrate the female reproductive apparatus among Dendroctonus species, clarify their nomenclature and evaluate their interspecific variation to propose useful characteristics for their identification. In addition, we evaluated whether there is a structure between the shape of the receptacle and the phylogenetic relatedness of the species. The spermatheca consists of a sperm duct, a receptacle, and a gland; of these elements, the receptacle is the most taxonomically informative structure. The most closely related species of the D. frontalis complex show wide intraspecific variation in the shape and size of this structure, which precludes recognition of diagnostic features. However, there are differences among species groups in both shape and size in less closely related species such as D. approximatus, D. mexicanus, D. micans, D. parallelocollis and D. rhizophagus. A phylogenetic signal was detected in receptacle shape, and patterns of morphological similarity and phylogenetic relatedness of species were evident in the D. frontalis complex.

Scapulaseius asiaticus (Evans) and S. reptans (Blommers) (Mesostigmata: Phytoseiidae): one or two species?

We compare published morphometric measurements of females and males of Scapulaseius asiaticus (Evans) and S. reptans (Blommers) collected in various countries, with new measurements and character states of type specimens of both species and additional material. The aim is to establish definitively whether the two species are synonyms or not. This paper follows the doubt on the taxonomic status of the former and the hypothesis of conspecificity of the two species formulated by both authors in previous papers concerning Mauritius phytoseiid fauna. Setal and shield measurements were highly similar between species. In addition, other morphological characters previously used to separate these taxa, such as the position of setae R1, showed a wide intraspecific variability, and largely overlapped between populations previously identified as S. asiaticus vs S. reptans. We conclude that the two forms are conspecific and, therefore, S. reptans is herein designated a junior synonym of S. asiaticus.

Application of multivariate morphometrics to delimit three Japanese species of Arisaema sect. Pistillata (Araceae)

The Arisaema serratum group sensu stricto (Araceae) is a Japanese species assemblage characterized by a well‐developed leaf rachis and a long pseudostem. It has been regarded as a complex including many species with few decisive traits. They were previously considered as a single species due to their wide intraspecific variation, but recent monographs have recognized about 13 species. In this group, A. maekawae and A. pseudoangustatum var. pseudoangustatum were recently divided from A. angustatum from the type localities. An earlier study found sympatric populations of the three species in the Chugoku region, far from the type localities, and distinguished them by qualitative observations, but there are no quantitative data to delimit the species boundaries objectively. Since high phenotypic plasticity hinders species delimitation in the A. serratum group s.s. using just a few quantitative traits, I investigated the morphological discontinuity among them using principal component analysis with eleven quantitative characters. In an ordination space including the three species, the morphological variation was roughly divided into A. maekawae and the others, and largely overlapped between A. angustatum and A. pseudoangustatum var. pseudoangustatum. However, the morphological variation clearly distinguished the two latter species when A. maekawae was excluded from the PCA. To conclude, the three Arisaema species appeared to be morphologically distinct. The strong reproductive isolation reported previously also ensures the species distinction according to the biological species concept. The discriminating traits between A. angustatum and the other two species partly differed from those in the type localities, suggesting that examination of intraspecific variation is needed between geographically isolated populations. This study showed that a combination of quantitative traits effectively supports tentative species identifications using qualitative traits and reinforces the usefulness of multivariate morphometrics for future systematic studies.

Morphology, Phenology, Yield, and Quality of Durum Wheat Cultivated within Organic Olive Orchards of the Mediterranean Area

In the current context of climate change, tree–crop combinations in agroforestry systems are suggested to mitigate water and heat stresses, particularly in semi-arid environments of the Mediterranean area. In this framework, a 3-year trial was conducted at the French National Research Institute for Agriculture, Food and the Environment (INRAE) in Mauguio (Southern France) in order to investigate the response of twenty-five durum wheat genotypes under a yearly pruned (AF) and a never-pruned alley olive orchard (AF+), in comparison with an open field without trees (control, C). The grain yield of wheat was markedly reduced in both the agroforestry systems AF (average −43%) and AF+ (−83%), according to the shading level. Among the yield components, the plant density at harvest was enhanced in AF (+22%) and AF+ (+3%), although with a significant reduction in the number of grains per spike (−37% in AF and −62% in AF+), and the number of spikes per plant (−32% in AF and −52% in AF+). The thousand-grain weight (TGW) and harvest index (HI) were slightly higher under moderate shade (AF; +12% vs. C) and severe shading (AF+; +6%). Plant biomass and spike size were significantly reduced in both agroforestry systems, while the flag leaf–spike distance (last internode) increased in AF. It was concluded that the moderate shading conditions of AF may create a sustainable agricultural system, and the wide intraspecific variability suggested a large scope for screening suitable genotypes, helping to produce ideotypes to implement agroforestry-oriented breeding programs.

Size-frequency distribution of coral assemblages in insular shallow reefs of the Mexican Caribbean using underwater photogrammetry.

The characterisation of changes in coral communities depends heavily on systematic monitoring programs and the collection of necessary metrics to assess reef health. Coral cover is the most used metric to determine reef health. The current organizational shift in coral requires the evaluation of complementary metrics, such as colony size and frequency distributions, which help to infer the responses of the coral populations to local stress or larger scale environmental changes. In this study, underwater digital photogrammetry techniques were used to assess the live cover of all coral colonies ≥3 cm2 and determine the size-frequency distribution of the dominant species in the shallow reefs of the Cozumel Reefs National Park (CRNP). In addition, the minimum sampling area (m2) needed to obtain a representative sample of the local species pool was estimated. Areas between 550 and 825 m2 per reef were photographed to generate high-resolution digital ortho-mosaics. The live area of the colonies was digitised to generate community matrices of species and abundance. EstimateS software was used to generate accumulation curves and diversity (Shannon H′) at increasing area intervals. Chi-Square tests (χ2, p = 0.05) were used to compare the observed vs estimated species richness. Spearman’s coefficients (rs), were calculated to correlate the increase in sampling area (m2) vs H′, and the Clench’s function was used to validate the observed richness (R2 = 1 and R > 90%). SIMPER analysis was performed to identify dominant species. Comparisons in terms of abundance, coral cover and size-frequencies were performed with Kruskal-Wallis (H test, p = 0.05), and paired Mann-Whitney (U test, p = 0.05). In order to obtain 90% of the species richness, a minimum sampling area of 374 m2is needed. This sampling area could be used in shallow Caribbean reefs with similar characteristics. Twelve (mainly non-massive) species: Agaricia agaricites, A humilis, A. tenuifolia, Eusmilia fastigiata, Meandrina meandrites, Montastrea cavernosa, Orbicella annularis, Porites astreoides, P. porites, Pseudodiploria strigosa, Siderastrea radians andS. siderea, were dominant in terms of abundance and coral cover. A significant increase (p < 0.05) in the number of colonies and live coral (m2) was observed from north to south of the study area. Furthermore, a wide intraspecific variation of size-frequency, even between adjacent reefs, was also observed. The size-frequency distributions presented positive skewness and negative kurtosis, which are related to stable populations, with a greater number of young colonies and a constant input of recruits. Considering the increase in disturbances in the Caribbean and the appearance of a new coral disease, digital photogrammetry techniques allow coral community characteristics to be assessed at high spatial resolutions and over large scales, which would be complementary to conventional monitoring programs.

Redescription of Milnesium alpigenum Ehrenberg, 1853 (Tardigrada: Apochela) and a description of Milnesium inceptum sp. nov., a tardigrade laboratory model.

Intra- and interspecific variability, being at the very core of alpha taxonomy, has been a long-standing topic of debate among tardigrade taxonomists. Early studies tended to assume that tardigrades exhibit wide intraspecific variation. However, with more careful morphological studies, especially those incorporating molecular tools that allow for an independent verification of species identifications based on phenotypic traits, we now recognise that ranges of tardigrade intraspecific variability are narrower, and that differences between species may be more subtle than previously assumed. The taxonomic history of the genus Milnesium, and more specifically that of the nominal species, M. tardigradum described by Doyère in 1840, is a good illustration of the evolution of views on intraspecific variability in tardigrades. The assumption of wide intraspecific variability in claw morphology led Marcus (1928) to synonymise two species with different claw configurations, M. alpigenum and M. quadrifidum, with M. tardigradum. Currently claw configuration is recognised as one of the key diagnostic traits in the genus Milnesium, and the two species suppressed by Marcus have recently been suggested to be valid. In this study, we clarify the taxonomic status of M. alpigenum, a species that for nearly a century was considered invalid. We redescribe M. alpigenum, using a population collected from the locus typicus, by the means of integrative taxonomy, i.e. including light microscopy, scanning electron microscopy, ontogenetic observations, and genetic barcoding. Moreover, the redescription of M. alpigenum allowed us to verify the uncertain taxonomic status of two popular laboratory models that were originally considered to be M. tardigradum; though one was recently reidentified as M. cf. alpigenum. Our analysis showed that both laboratory strains, despite being morphologically and morphometrically nearly identical to M. alpigenum, in fact represent a new species, M. inceptum sp. nov. The two species, being disnguishable only by statistical morphometry and/or DNA sequences, are the first example of pseudocryptic species in tardigrades.

A Possible Phylogenetic Relationship of Two Species of Hyphantoceras (Ammonoidea, Nostoceratidae) in the Cretaceous Yezo Group, Northern Japan

A possible phylogenetic relationship of two species of Hyphantoceras (Ammonoidea, Nostoceratidae) was proposed, based on newly found specimens with precise stratigraphic occurrences in the Kotanbetsu and Obira areas, northwestern Hokkaido. Two closely related species, Hyphantoceras transitorium and H. orientale, were recognized in the examined specimens from the Kotanbetsu and Obira areas. Specimens of H. transitorium show wide intraspecific variation in the whorl shape. The stratigraphic occurrences of the two species indicate that they occur successively in the Santonian–lowermost Campanian, without stratigraphic overlapping. The similarity of their shell surface ornamentations and the stratigraphic relationships possibly suggest that H.orientale was derived from H. transitorium. The presumed lineage is likely indigenous to the northwestern Pacific realm in the Santonian–earliest Campanian. Hyphantoceras venustum and H. heteromorphum might stand outside a H. transitorium–H. orientale lineage, judging from differences of their shell surface ornamentation.

Distinct protoconchs recognised in three of the larger Mediterranean Cerithium species (Caenogastropoda: Cerithiidae)

ABSTRACTThe gastropod genus Cerithium includes several polymorphic species which are hardly distinguishable using a morphological approach based on teleoconch characters. Here we show that protoconch characters can be reliably used to identify the larger Mediterranean species (Cerithium alucastrum, C. repandum and C. vulgatum), and to assess their intraspecific variability. Based on a large amount of morphological data, we show that a multispiral, strongly sculptured protoconch (traditionally associated with C. vulgatum) is found in C. alucastrum. This species originated in the Pliocene. A multispiral, weakly sculptured protoconch, not observed previously, is reported for C. vulgatum. A paucispiral protoconch, distinct from those observed previously for C. lividulum and C. renovatum, is reported for C. repandum and can be used for recognising its wide intraspecific variation and understanding its geographical distribution. Cerithium repandum, previously doubtfully recorded outside its type locality, extends back to the mid-Pliocene and is today rather widely distributed in the Mediterranean, although absent from the Aegean Sea and the Alboran Sea. We describe the larval development of C. repandum and C. vulgatum for the first time, confirming their respective non-planktotrophic and planktotrophic development previously inferred from protoconch morphology. Also, we report a possible case of morphological convergence between C. repandum and C. vulgatum occurring in harbour sites, where we found a distinct (possibly Anthropocene) shell form not described previously from other Recent or fossil material.

Undercover speciation of wentletraps (Caenogastropoda: Epitoniidae) in the Southwestern Atlantic

Despite being one of the most speciose families, Epitoniidae still remains at present as one of the least understood gastropod families worldwide. This is a consequence of most of the species being only known from shell morphology, added to the wide intraspecific variability of this character and the fact that shell morphology has proven to have frequent examples of parallelisms and convergences among different (unrelated) species. Knowledge of other morphological and anatomical characters in this group is still in its first steps, and such information is currently available for a limited number of species, thus being difficult (when not impossible) to evaluate its taxonomic value. The aim of this study is to re-evaluate the diversity of Epitoniidae occurring in the Atlantic coast of Patagonia. As part of this study, the validity of only four of the six species described / reported from this area could be confirmed: Epitonium georgettinum, E. striatellum, E. fabrizioi and “Cirsotrema” magellanicum. In addition, three new species were recognized and are described herein: Epitonium evanidstriatum, “Cirsotrema” ctenodentatum and “Cirsotrema” strebeli. Information on the shell (including the protoconch), operculum, radula and jaw for these species is here provided, in most cases for the first time. A neotype for Scalaria magellanica is here designated. Furthermore, “Cirsotrema” georgeanum is here proposed as a replacement name for Scalaria fenestrata Strebel, 1908 (not Meneghini in de Stefani, 1875, nor Scalaria fenestrata Wöhrmann, 1889); and that taxon is regarded as a full species, instead of as a synonym of “Cirsotrema” magellanicum, as suggested in some previous publications. This study reveals that the usage of isolated (either morphological or anatomical) characters is usually insufficient for identifying some of the species from Patagonia; however, if these characters are combined, all species may be clearly recognized.

Rediagnosis of &lt;i&gt;Onigocia grandisquama&lt;/i&gt; (Actinopterygii: Perciformes: Platycephalidae) and Comparison with Congeners

A platycephalid fish, Onigocia grandisquama ( Regan, 1908 ) is rediagnosed based on 52 specimens, including the holo-type, from the Indo-West Pacific. Geographic variation in the species was recognized in the number of pectoral-fin rays, the first example of such variation in fin ray counts in the Platycephalidae. The species displays wide intraspecific variation in the numbers of lachrymal, preocular, suborbital, and pterotic spines, with values for the first two overlapping with those of the very similar Onigocia spinosa (Temminck and Schlegel, 1843), making it difficult to separate the two. Onigocia grandisquama can be distinguished from O. spinosa, as well as from Onigocia macrocephala (Weber, 1913) and Onigocia macrolepis (Bleeker, 1854), which share with O. grandisquama an ocular flap on the posterior part of the eye, in lacking spines on the inner, middle, and/or outer ridges of the lachrymal. The generally greater number of pterotic spines also helps to separate O. grandisquama from its three congeners.

Dichelyne (Cucullanellus) romani n. sp. (Nematoda: Cucullanidae) in notacanthid fishes from the Northeast Atlantic and Western Mediterranean.

A new cucullanid, Dichelyne (Cucullanellus) romani n. sp. (Nematoda: Cucullanidae), is described from the digestive tract of two notacanthid fishes, Notacanthus chemnitzii Bloch and N. bonaparte Risso (Notacanthiformes: Notacanthidae), from the Northeast Atlantic and Western Mediterranean. The presence of a precloacal sucker and ten pairs of caudal papillae in males allocates it to the subgenus Cucullanellus Törnquist, 1931. The new species differs from other members of this subgenus in its larger body size, smaller spicule/body length ratio, the distribution of caudal papillae, and the position of deirids and excretory pore. Both notacanthid fishes act as definitive hosts with slightly larger nematode specimens detected in N. chemnitzii. A wide intraspecific variability was found in the distribution of caudal papillae, and in some specimens the position of deirids, excretory pore and length of intestinal caecum also varied. A complete list of all assigned species of the subgenus Cucullanellus is presented and discussed as there are several uncertainties regarding the validity and synonymy of some species. This is the first species of Dichelyne Jägerskiöld, 1902 in a notacanthid fish and one of the only two records in deep-sea fish species.

Growth and Body Weight Variability of the Invasive MusselLimnoperna fortunei(Mytilidae) Across Habitat and Season

The freshwater mussel Limnoperna fortunei is adapted to colonize a wide range of aquatic environments, and its ability to contend with environmental stress through phenotypic plasticity has allowed this species to successfully colonize and become established in new regions. Only limited information is currently available on the wide intraspecific variability of this species in response to environmental heterogeneity. Here, we tested the hypotheses that (1) growth and body weight of mussels from a highly polluted environment differed from those from a less polluted habitat, and (2) growth parameters estimated in this study differed from those reported for other invaded ecosystems. We conducted controlled field experiments in two study sites with differing levels of pollution. To compare our results to those reported elsewhere, we considered growth data from studies performed in different locations. We found that mussels from the more polluted habitat showed lower shell growth and body weight than those from the less polluted environment. We also observed differences in the growth performances of the golden mussel between our estimates and those from other invaded habitats. Our findings provide useful information to better understand the striking intraspecific variability of this species in response to stressful conditions. Knowledge on the phenotypic plasticity of L. fortunei is essential for predicting and managing this species.

Reassessment of morphological diagnostic characters and species boundaries requires taxonomical changes for the genus orthopyxis L. Agassiz, 1862 (campanulariidae, hydrozoa) and some related campanulariids.

The genus Orthopyxis is widely known for its morphological variability, making species identification particularly difficult. A number of nominal species have been recorded in the southwestern Atlantic, although most of these records are doubtful. The goal of this study was to infer species boundaries in the genus Orthopyxis from the southwestern Atlantic using an integrative approach. Intergeneric limits were also tested using comparisons with specimens of the genus Campanularia. We performed DNA analyses using the mitochondrial genes 16S and COI and the nuclear ITS1 and ITS2 regions. Orthopyxis was monophyletic in maximum likelihood analyses using the combined dataset and in analyses with 16S alone. Four lineages of Orthopyxis were retrieved for all analyses, corresponding morphologically to the species Orthopyxis sargassicola (previously known in the area), Orthopyxis crenata (first recorded for the southwestern Atlantic), Orthopyxis caliculata (= Orthopyxis minuta Vannucci, 1949 and considered a synonym of O. integra by some authors), and Orthopyxis mianzani sp. nov. A re-evaluation of the traditional morphological diagnostic characters, guided by our molecular analyses, revealed that O. integra does not occur in the study area, and O. caliculata is the correct identification of one of the lineages occurring in this region, corroborating the validity of that species. Orthopyxis mianzani sp. nov. resembles O. caliculata with respect to gonothecae morphology and a smooth hydrothecae rim, although it shows significant differences for other characters, such as perisarc thickness, which has traditionally been thought to have wide intraspecific variation. The species O. sargassicola is morphologically similar to O. crenata, although they differ in gonothecae morphology, and these species can only be reliably identified when this structure is present.

Molecular characterization of olive (Olea europaea L.) Sicilian cultivars using SSR markers

Olive (Olea europaea L.) is one of the economically most important fruit crops for the Mediterranean area, with production being mainly destined to oil extraction. In Sicily, olive has been cultivated since ancient times and its germplasm is characterized by a wide genetic diversity that could be related to its domestication and spread in ancient times, and to some reproductive biological peculiarities as self-incompatibility. This analysis was conducted on 65 genotypes with the purpose of characterizing a large collection of Sicilian accessions (47 genotypes) and to compare them with varieties coming from Southern Italy and from the most important countries of the Mediterranean basin. With this aim we used 8 simple sequence repeat (SSR) markers, which detected a total of 74 alleles and identified an average of 19.5 genotypes in the population investigated. A larger variability than expected was found in the analyzed genotypes, some synonymies already reported in literature were confirmed, but also some cultivars considered as identical were discriminated such as in the case of Castriciana, Ogliarola messinese and Passalunara. The whole study revealed a wide intraspecific variability within the gene pool examined, independently from the geographical origin.

Comparative analysis of Galea (Rodentia, Caviidae) and expanded diagnosis of Galea ortodonta Ubilla and Rinderknecht, 2001 (Late Pleistocene, Uruguay)

The family Caviidae is a diverse group of South American caviomorph rodents with many living and extinct taxa. Paleontological information about the caviid genus Galea is scant; only two extinct species have been described from fragmentary material so far. Recently, complete skulls and mandibles of the extinct Galea ortodonta have been found (Dolores Fm., Late Pleistocene; Santa Lucía river basin, southern Uruguay). Based on anatomical and quantitative analyses, we provide an expanded diagnosis and description of G. ortodonta, which thus becomes the best-known extinct species of the genus, accompanied by a critical assessment of skull, mandible and dental characters at the generic level. The wide intra-specific variability observed in several characters makes difficult to identify exclusive characters at the species level and to describe species based on fragmentary materials or on mandibles alone. G. ortodonta is characterized by the following associated features: large size; orthodont upper incisor; latero-external face of the incisors with extended enamel; small and laterally compressed auditory bullae; wide basioccipital; maxillary zygomatic process with apophysis; upper cheek teeth with external primary and secondary folds; palatine wide at the mesopterygoid fossa; and horizontal mandibular crest starting at p4. This character association differs from all other living and extinct species of the genus but resembles the G. musteloides species group to some extent. Biostratigraphic information and absolute ages support a Late Pleistocene age for the new material and a correlation with the late phases of Marine Isotope Stage MIS3. Galea occupied lowland areas in southern Uruguay during the Late Pleistocene and, like other associated mammals, suggests open or semi-open areas with an arid or semi-arid context, an environmental scenario arguably influenced by the late phases of MIS3.