A morphometric analysis of mandibular teeth in Folsomia (Collembola: Isotomidae)

Morphological variation in the apical mandibular teeth of seven Folsomia species (F. bisetosa, F. brevicauda, F. Candida, F. fimentaria, F. inoculata, F. penicula , and F. quadrioculata) was examined by canonical variates analysis of a systematic 'truss' of measurements. Differences were found between all but two species (F. brevicauda and F. quadrioculata) showing that the morphology of 'biting-type' mouthparts can be used for species recognition. The results also show that the truss system of measurement is sensitive to small-scale differences in the mandible morphology of these insects. It is suggested that variation in mouthpart morphology, and in patterns of tooth wear, reflect differences in the feeding behaviour of Folsomia species.     

The cold‐adapted population of Folsomia manolachei (Hexapoda,Collembola) from a glaciated karst doline of Central Europe: evidence for a cryptic species?

Folsomia manolachei Bagnall, 1939 (Collembola), is a widespread and common European species. However, it may represent a complex of species also associated with the climatically more extreme environments of the karst landforms. Three species of the genus Folsomia, distributed in the Slovak Karst region (Central Europe), namely three different populations of F. manolachei, and one population of F. penicula and F. candida, were analysed using a partial sequence of the mitochondrial cytochrome c oxidase subunit I (COI barcoding section). The DNA barcoding suggested the existence of cryptic diversity in populations of the eurytopic species Folsomia manolachei. The cold‐adapted population of ‘F. manolachei’ was abundant in primary soil on stony debris near the permanent floor ice (yearly air temperature ~0°C) in the collapsed karst doline of the Silická ?adnica Ice Cave. It showed a genetic differentiation supported by intra‐ and interspecific distances that ranged from 0.0% to 1.4% and from 19.2% to 24.0%, respectively. Analysis using Taxon DNA showed a large barcoding gap between intra‐ and interspecific COI sequences. Genetic differentiation suggests a scenario of cryptic speciation in the population of ‘F. manolachei’ occupying harsh soils near the floor ice. A survival test showed the different responses of ‘F. manolachei’ and other populations to low temperature. Within a temperature range from ?3 to ?10°C, the ‘F. manolachei’ population from Silická ?adnica was the most cold‐resistant, showing a lethal dose LD₅₀ of ?7.8°C. The two forest populations of F. manolachei had LD₅₀ ?6.1°C and ?6.0°C, respectively; the most cold‐sensitive F. penicula showed an LD₅₀ of ?5.4°C. The survival of the tested springtails significantly decreased with temperature (p < 0.0001). The lethal temperature and the shape of the survival–temperature curves were different in different populations. The impact of population was significant at p < 0.0001, and the interaction between population and temperature at p < 0.039 was significant as well. Crypticity vs. phenotypic plasticity in Folsomia manolachei populations is discussed in terms of DNA barcoding and the cold tolerance data provided by this study.     

Patterns of abundance and demography: Collembola in a habitat patch gradient

The demography and abundance of Collembola in relation to a gradient of increasingly isolated tussocks of Carex ursina were investigated near Ny-Alesund, Svalbard The study area was divided into three zones according to tussock density Ten tussocks were sampled in each zone In addition, samples were taken between tussocks, which consisted of ground covered with a layer of cyanobacteria A total of ten Collembola species were found, five of which were chosen for further studies The Carex tussocks were the preferred habitat for the majority of these species Only one species, Hypogastrura viatica, was found regularly between tussocks, although at low density The gradient in tussock distribution was probably an important factor in determining the distribution, abundance and the underlying demographic processes of most species This was indicated by an increase in demographic heterogeneity with patch isolation The different species were affected differently, however Whereas one species appeared to be unaffected by the gradient (H viatica), two species (H longispina) and (Folsomia sexoculata) were somewhat surprisingly found to have their highest density where tussocks were furthest apart Factors other than the spatial configuration of the habitat are probably important in determining the distribution of these two species, indicated by a positive correlation at tussock level between them In accordance with general hypotheses on the effect of patchiness on population dynamics the remaining two species, F quadrioculata and Onvchiurus groenlandicus, occurred in very low numbers or not at all, respectively, in the zone where tussocks were furthest apart Their response is probably dependent on their ability to successfully colonise isolated tussocks We predict that different species specific demographic strategies, and in particular dispersal rates may account for the observed patterns     

The phylogeny of Halgerda (Opisthobranchia, Nudibranchia) with the description of a new species from Okinawa

This paper proposes a refined hypothesis of evolution for the tropical Indo-Pacific nudibranch genus Halgerda . Numerous specimens from 31 species were examined anatomically and literature from four additional species was reviewed, bringing to 33 the ingroup taxa. Fifty-three characters were considered from these examinations. The outgroup Asteronotus was used to polarize the characters. The phylogeny obtained from the analysis of the characters supports the hypothesis that Halgerda is a monophyletic group. A species previously placed with the genus Sclerodoris is examined and determined to be a member of the genus Halgerda . Phylogenetic analysis places this species, H. paliensis , as a basal member of the genus . Halgerda paliensis appears to be restricted to the Hawaiian Islands. Specimens previously identified as Sclerodoris paliensis from the Marshall Islands actually represent H. dalanghita Fahey & Gosliner, 1999. A new species, Halgerda onna , is described and presented as the sister taxon to a basal member of the genus. A range and depth extension of a previously described species, H. malesso , is presented. The present phylogeny is then compared to previous studies, in particular those of Fahey & Gosliner (1999a,b) .     

Morphometric convergence and molecular divergence: the taxonomic status and evolutionary history of Gymnura crebripunctata and Gymnura marmorata in the eastern Pacific Ocean

To clarify the taxonomic status of Gymnura crebripunctata and Gymnura marmorata , the extent of morphological and nucleotide variation between these nominal species was examined using multivariate morphological and mitochondrial DNA comparisons of the same characters with congeneric species. Discriminant analysis of 21 morphometric variables from four species ( G. crebripunctata , G. marmorata , Gymnura micrura and Gymnura poecilura ) successfully distinguished species groupings. Classification success of eastern Pacific species improved further when specimens were grouped by species and sex. Discriminant analysis of size-corrected data generated species assignments that were consistently accurate in separating the two species (100% jackknifed assignment success). Nasal curtain length was identified as the character which contributed the most to discrimination of the two species. Sexual dimorphism was evident in several characters that have previously been relied upon to distinguish G. crebripunctata from G. marmorata . A previously unreported feature, the absence of a tail spine in G. crebripunctata , provides an improved method of field identification between these species. Phylogenetic and genetic distance analyses based on 698 base pairs of the mitochondrial cytochrome b gene indicate that G. crebripunctata and G. marmorata form highly divergent lineages, supporting their validity as distinct species. The closely related batoid Aetoplatea zonura clustered within the Gymnura clade, indicating that it may not represent a valid genus. Strong population structuring (overall Φ _ST = 0·81 ,P < 0·01) was evident between G. marmorata from the Pacific coast of the Baja California peninsula and the Gulf of California, supporting the designation of distinct management units in these regions.     

Redescription of Gyrodactylus teuchis Lautraite,Blanc, Thiery,Daniel & Vigneulle, 1999 (Monogenea: Gyrodactylidae); a species identified by ribosomal RNA sequence

Molecular and morphological features of Gyrodactylus specimens from Oncorhynchus mykiss, Salmo trutta and Salmo salar were examined. Sequences from variable region V4 of the small subunit ribosomal RNA gene and the ribosomal RNA internal transcribed spacers, produced by the FRS Marine Laboratory, revealed that these were not the same as other well-characterised Gyrodactylus that are common on European salmonids and were in fact a distinct species. Initial morphological examination of the opisthaptor indicated that this species very closely resembles G. salaris Malmberg, 1957. More detailed analysis revealed differences in the shape of the marginal hook sickle of these two species and thus Gyrodactylus teuchis Lautraite, Blanc, Thiery, Daniel & Vigneulle, 1999 was erected. Analysis of the ribosomal RNA gene or spacer sequences remains the most reliable method of identifying this species. This is believed to be the first record of a Gyrodactylus species identified first from molecular data and confirmed by morphological examination; previous molecular analyses had provided alternative methods for identifying species that had already been described using morphological characters.     

Experimental manipulation of the winter surface ice layer: the effects on a High Arctic soil microarthropod community

The effect of patch size on the tolerance of the soil microarthropod population to an experimentally induced environmental catastrophe, a thick surface ice layer, was studied at a High Arctic site (78°55 'N, 11°53' E). Such an ice layer currently occurs infrequently; however, climate change models suggest that the occurrence of such an ice layer is likely to increase in frequency. The experimental approach was a factorial design with two patch sizes, an icing treatment and controls. A thin layer of natural ice was present even in the controls and this was treated as a covariate in the analysis. The soil microarthropod fauna at the experimental site consisted of five species of Collembola and seven species of oribatid mite. The experimental surface ice layer reduced the total number of the soil microarthropods studied by 50%; however, mortality differed between mites and Collembola and species within the two taxo-nomic groups. Mites were very resistant and showed no significant change, Collembola more sensitive (the populations of Hypogastrura tullbergi declined by 56% and Folsomia quadrioculata by 54'% in the iced treatment plots). The thin annual surface ice layer seemed to have an additional effect on H. tullbergi and the mite Lauroppia translamcllata. That such a thin ice layer could reduce survival was unexpected and could play an important role in determining the extreme patchy distribution of arctic soil animals.     

Morphometric analysis of male genitalia in sibling species of Drosophila virilis Sturt

The structure of male genital organs in sibling species of the virilis group of Drosophila was examined using methods of multivariate statistics. The differences among these species were estimated using 33 indices and 2 angle parameters. The intraspecific and interspecific correlation structure of the examined characters and the order of their divergence were established. The key characters with respect to forming interspecific differences in the virilis species group were identified. Based on these results, the relative systematic positions of the sibling species are discussed as well as similarities and differences of the pattern of relationships among the species from that generally accepted for the virilis group.     

Morphological identification of Lucilia sericata,Lucilia cuprina and their hybrids (Diptera,Calliphoridae)

Hybrids of Lucilia sericata and Lucilia cuprina have been shown to exist in previous studies using molecular methods, but no study has shown explicitly that these hybrids can be identified morphologically. Published morphological characters used to identify L. sericata and L. cuprina were reviewed, and then scored and tested using specimens of both species and known hybrids. Ordination by multi-dimensional scaling indicated that the species were separable, and that hybrids resembled L. cuprina, whatever their origin. Discriminant function analysis of the characters successfully separated the specimens into three unambiguous groups – L. sericata, L. cuprina and hybrids. The hybrids were morphologically similar irrespective of whether they were from an ancient introgressed lineage or more modern. This is the first evidence that hybrids of these two species can be identified from their morphology. The usefulness of the morphological characters is also discussed and photographs of several characters are included to facilitate their assessment.     

Molecular phylogeny and species recognition in the mealybug genus Ferrisia Fullaway (Hemiptera: Pseudococcidae)

Previous allozyme and DNA nucleotide sequence studies of the mealybug genus Ferrisia Fullaway (Hemiptera: Pseudococcidae), although limited, have suggested greater species diversity than is recognized by the current morphology‐based taxonomy. Here we analyse nucleotide sequence data from one mitochondrial (cytochrome oxidase I) and two nuclear (EF‐1α and 28S D₂D₃) genes and recover ten well‐supported groups that allow us to reassess the taxonomic utility of morphological characters used for species recognition. We report on previously used morphological characters for which states are highly variable within genetic groups and identify new characters (of the wax‐exuding cuticular ducts and pores) with taxonomically informative states. The widespread pest species F. virgata (Cockerell), commonly called the striped mealybug, should be diagnosed more narrowly. From samples identified as F. virgata, we recover six clades that we equate with species and that can be distinguished with the newly identified morphological characters. We determine that five of the ‘electrophoretic species' identified informally by the late Uzi Nur based on electrophoretic mobility of 20 enzymes correlate with four of our genetic groups. This matching of Nur's putative species with ours was possible only because some of Nur's slide‐mounted voucher specimens were deposited in a museum and thus available for morphological study. Species confused with F. virgata are either new to science or were placed erroneously in synonymy with F. virgata by earlier authors: they will be described elsewhere. The most important characters of the adult female for distinguishing these species from F. virgata are the positions and characteristics of minute discoidal pore(s) associated both with the ventral oral‐collar tubular ducts and with the sclerotized area surrounding each dorsal enlarged tubular duct, and the number of sizes of the ventral oral‐collar tubular ducts. In addition, we determine that adult females of F. gilli Gullan from different populations on different host plants vary substantially in the number and size of clusters of small ventral oral‐collar ducts on the body margins – features previously suspected to indicate distinct species.     

SPECIES BOUNDARIES IN THE TOXIC DINOFLAGELLATE PROROCENTRUM LIMA (DINOPHYCEAE,PROROCENTRALES), BASED ON MORPHOLOGICAL AND PHYLOGENETIC CHARACTERS1

Wild and cultured specimens of Prorocentrum lima (Ehrenb.) F. Stein from 26 widely different areas in 13 countries were examined in order to determine consistent characters for delimiting species boundaries in this taxon. The morphological characters valve shape, valve size, valve ornamentation, number and shape of valve pores, number and shape of marginal pores, and periflagellar platelets were observed using LM and SEM, and two molecular genetic regions were sequenced. We identified stable morphological characters that were consistent among wild specimens and all cultures, which were valve shape, valve ornamentation, and number and arrangement of periflagellar platelets. All cultures of P. lima identified by these characters formed a monophyletic group in phylogenetic analyses based on the two genes, which, however, included the species Prorocentrum arenarium. P. arenarium was determined to be within the range of morphological variation of P. lima, and therefore we synonymize the two taxa. Within this monophyletic group, P. lima was divided into several subclades in the all phylogenetic analyses. There were no morphological characters specifically related to any one subclade. The subclades appeared to correlate broadly to sample collection regions, suggesting that geographically separated populations may have become genetically distinct within this epi‐benthic species. We have emended species boundaries in P. lima.     

An assessment of morphometric variability between populations of Longidorus vineacola Sturhan & Weischer, 1964 (Nematoda: Longidoridae) and morphologically related species

Morphometrics of female specimens from 46 populations and species belonging to the Longidorus vineacola Sturhan & Weischer, 1964 'complex' were examined. L. vineacola was present as 36 populations; L. attenuatus Hooper, 1961 and L. cohni Heyns, 1969 each as two populations; and L. apulus Lamberti & Bleve-Zacheo, 1977 , L. closelongatus Stoyanov, 1964 and L. pseudoelongatus Altherr, 1976 each as a single population. Specimens from two populations from France and Italy which had originally been identified as L. vineacola were found to be L. paraelongatus Altherr, 1974 and L. proximus Sturhan & Argo, 1983, respectively. A population from the Netherlands represented an unidentified species but the number of specimens available was insufficient to establish a new species. In a canonical variate analysis using the five morphometric characters of body, odontostyle, odontophore, anterior to guide ring and tail lengths, the L. vineacola populations formed several clusters and the other species formed separate clusters. All 46 populations formed a homogeneous group at 87% level of similarity. It is concluded that the five morphological characters used for the analysis provide a reliable means for distinguishing members of the L. vineacola complex of morphologically similar species. L. apuloides Roca, 1996 is considered a junior synonym of L. vineacola.     

Morphometric Analysis of Male Genitalia in Sibling Species of Drosophila virilis Sturt.

The structure of male genital organs in sibling species of the virilis group of Drosophila was examined using methods of multivariate statistics. The differences among these species were estimated using 33 indices and 2 angle parameters. The intraspecific and interspecific correlation structure of the examined characters and the order of their divergence were established. The key characters with respect to forming interspecific differences in the virilis species group were identified. Based on these results, the relative systematic positions of the sibling species are discussed as well as similarities and differences of the pattern of relationships among the species from that generally accepted for the virilis group.     

Taxonomic revision of Joyeuxilepis Spassky, 1947 (Cestoda: Amabiliidae): redescriptions of J. biuncinata (Joyeux & Baer, 1943), J. decacantha (Fuhrmann, 1913) and J. pilatus Borgarenko & Gulyaev, 1991

Two species of Joyeuxilepis Spassky, 1947 are redescribed from Tachybaptus ruficollis in Bulgaria: J. biuncinata (Joyeux & Baer, 1943) and J. pilatus Borgarenko & Gulyaev, 1991. The syntypes of J. decacantha (Fuhrmann, 1913) from Podiceps cristatus in Sweden and voucher specimens of J. pilatus (identified as 'Tatria decacantha') from T. ruficollis in England (new geographical record) from the British Museum (Natural History) Collection are also re-described. The voucher specimens and cysticercoids of Tatria spp. from dragonfly nymphs in Wales recorded by Rees (1973) were re-examined. Previous records of J. biuncinata, J. decacantha and J. pilatus are critically analysed in view of the present results. The major reliable diagnostic characters for species of Joyeuxilepis are presented and the distinguishing criteria for the three species studied are re-evaluated.     

Mosquito (Diptera: Culicidae) grouping based on larval habitat characteristics in high mountain ecosystems of Antioquia,Colombia

Information about mosquito ecology in the high mountain ecosystems of the Neotropical region is sparse. In general, few genera and species have been reported in these ecosystems and there is no information available on habitats and the mosquitoes occupying them. In the present study, specimens collected from NW Colombia in HME were grouped using larval habitat data via an Operational Taxonomic Unit (OTU) determination. A total of 719 mosquitoes was analyzed belonging to 44 OTUs. The analysis considered habitat features and clustered the specimens into six groups from A‐F. Five of these included species from different genera, suggesting common habitat requirements. Group E with four genera, seven subgenera, and six species occupied the highest areas (above 3,000 m), whereas three groups (B, D, F) were detected at lower altitudes (1,960–2,002 m). Bromeliads were the most common larval habitat, with 47% (335/719) of the specimens; five genera, six subgenera, and eight species were identified and classified into 66% (29/44) of the OTUs. This work showed some similarities to the habitat requirements and provides a grouping system that constitutes an important baseline for the classification of mosquito fauna from high mountain ecosystems according to altitude and larval habitat.     

The species distinction of the narrow-leaved Festuca from East Africa based on AFLP fingerprinting and morphology

The distinctness of the species Festuca claytonii , F. elgonensis and F. pilgeri (endemic species in East Africa) was assessed by comparison to the widespread narrow-leaved species F. abyssinica , F. chodatiana and F. richardii . The six species were analysed using 56 morphological characters and 375 AFLPs. Principal components and discriminant analyses of the morphological data revealed that the endemic species F. claytonii and F. pilgeri are good species, but that F. abyssinica, F. elgonensis and F. richardii do intergrade. Relevant morphological characters were identified for an overall species distinction but also for pairwise comparisons. A principal coordinate analysis of the AFLPs confirmed the species distinction mentioned above. In conclusion, four narrow-leaved species of Festuca occur in Uganda, viz. F. abyssinica , F. chodatiana , F. claytonii and F. pilgeri . F. elgonensis and F. richardii should be included in F. abyssinica . A key to the species is given.     

The phyletic position and systematics of the douc langurs of Southeast Asia

In recent years, two major questions concerning the phyletic relationships and systematic position of the douc langurs have arisen. These concern, firstly, the taxonomic level at which the doucs as a group should be distinguished and, secondly, the number of taxa of doucs that should be recognized. It has recently been demonstrated on the basis of an exhaustive phylogenetic analysis that the doucs are generically distinct from the snub-nosed langurs and that they should be referred to as species of Pygathrix and Rhinopithecus, respectively [Jablonski and Peng, Folia Primatologica 60:36–55, 1993]. The present investigation was directed toward testing this conclusion using an expanded data set and a different method of character coding, and toward addressing the question as to the number of species or subspecies of doucs that should be recognized. A wide variety of data from large samples of doucs (n = 38), snub-nosed langurs (n = 53), and an out group (macaques; n = 191) were assembled, coded, and analyzed using an interactive computerized program for phylogenetic analysis. The specimens of Pygathrix examined included skeletal specimens, skins, and, when possible, living animals representing the three recognized taxa of doucs, nemaeus nigripes, and moi. The data base for the study comprised 178 characters, including measurements of skeletal specimens (98 characters), qualitative (presence or absence) morphological features (36 characters), characteristics of the pelage (39 characters), and 5 miscellaneous characters. The conclusions of the study were that 1) as a group, the taxa of Pygathrix preserved a larger number of primitive features for the Pygathrix-Rhino-pithecus clade than did the taxa of Rhinopithecus; 2) the taxa of Pygathrix were less different from one another than are the species of Rhinopithecus were from one another; 3) the subspecies Pygathrix nemaeus moi Kloss, 1926 be synonymized with Pygathrix nemaeus nigripes, as suggested by Napier [Catalogue of Primates in the British Museum (Natural History) and Elsewhere in the British Isles. Port III Family Cercopithecidae, Sub-Family Colobinae. London, 1985]; 4) the extant doucs were best recognized as two subspecies, P. nemaeus nemaeus for the red-shanked douc and P. nemaeus nigripes for the black-shanked douc; and 5) the phylogeny of the doucs and snub-nosed langurs proposed by Jablonski and Peng[op cit.,1993] was found to be robust. © 1995 Wiley-Liss, Inc.     

Rhabdias esculentarum n. sp. (Nematoda: Rhabdiasidae) from green frogs of the Rana esculenta species complex in Italy: molecular evidence, morphological description and genetic differentiation from its congeners in frogs and toads

A new taxon, Rhabdias esculentarum n. sp., is described based on DNA sequence analysis at multiple loci (i.e. mtDNA cox-1, 12S rRNA, ITS-1 and partial ITS-2 regions of the nuclear rDNA) and morphometric analysis carried out on specimens collected from the green frogs of the Rana esculenta species complex in Italy (i.e. R. lessonae Camerano and R. esculenta Linnaeus, identified genetically by diagnostic allozyme loci). Rhabdias esculentarum n. sp. was differentiated genetically, at both mitochondrial and nuclear levels, from Rh. bufonis (Schrank, 1788) (sensu Hartwich, 1972) and Rh. sphaerocephala Goodey, 1924 recovered from the toad Bufo bufo Linnaeus collected sympatrically with the specimens of Rana lessonae and R. esculenta examined in the present study. Moreover, the new taxon proved to be different from the other species of Rhabdias from anurans, which had previously been sequenced using the same genes and deposited in GeneBank. Phylogenetic analyses (MP and ML) inferred from mitochondrial (mtDNA cox-1 and 12S ribosomal RNA) and nuclear (ITS-1 and ITS-2 of the rDNA regions) sequences datasets were congruent in depicting Rh. esculentarum n. sp. as forming a highly supported clade distinct from the sympatric species Rh. bufonis, as well as from Rh. sphaerocephala, characterised on the basis of the same loci. Morphometric analysis and the differential diagnosis of genetically characterised specimens of the new species have revealed differences in several features in comparison with the type-species, Rh. bufonis. Material of the latter species included voucher specimens from Germany deposited by Hartwich (1972) and other specimens collected from B. bufo in Italy. Among the diagnostic characters, the particular cup-shaped buccal capsule characterising Rh. esculentarum is clearly different from the tear-shaped buccal capsule observed in material of R. bufonis obtained from Berlin Museum and collected in the same geographical area as the green frogs under study. Rh. esculentarum was also found to differ in some measurements and allometric characters from Rh. bufonis (sensu Moravec et al., 1997). The data so far collected appear to indicate a host-preference of Rh. esculentarum for Rana lessonae and R. esculenta, which belong to the R. esculenta hybridogenetic species complex in Italy.     

Redescription of Folsomia loftyensis Womersley with notes on the sensillary arrangement of the genital segment in the genus (Collembola: Isotomidae)

Folsomia loftyensis Womersley is redescribed based on material from South Australia, Victoria and Queensland. The species exhibits, for the genus, an unusual sensillary pattern on the posterior abdominal segments. The arrangement and form of the five sensilla on the genital segment of most described species of Folsomia from the Palearctic are analysed and species divided into groups based on these characters. Several different lineages are detected.