Morphometric study of the Pissodes strobi complex (Coleoptera: Curculionidae)

2002 ◽  
Vol 134 (4) ◽  
pp. 447-466 ◽  
Author(s):  
Daryl J.M. Williams ◽  
David W. Langor
Keyword(s):  
Body Size ◽  
Morphological Characters ◽  
Resolving Power ◽  
Morphometric Study ◽  
Stepwise Discriminant Analysis ◽  
Western North America ◽  
Discriminant Functions ◽  
Canonical Variates Analysis ◽  
Pissodes Strobi ◽  
Canonical Variates

AbstractMorphometric data were collected on 15 characters in adults of the species of the Pissodes strobi complex (P. nemorensis (Germar), P. schwarzi Hopkins, P. strobi (Peck), and P. terminalis Hopping). Data were examined using stepwise discriminant analysis to determine if all characters contribute significantly to the diagnosis of taxa, and their relative amounts of resolving power were illuminated using canonical variates analysis. Discriminant functions were generated to diagnose species. Separate discriminant functions were generated for each sex for populations from eastern and western North America. Significant sexual dimorphism and variability in body size decrease the utility of morphological characters for diagnosis, but did not prevent the formulation of useful discriminant functions, particularly when selected ratios that control for body size were added.

Clonal structure and fertility in a sympatric population of the peat mosses Sphagnum rubellum and Sphagnum capillifolium

1996 ◽  
Vol 74 (9) ◽  
pp. 1375-1385 ◽  
Author(s):  
Nlls Cronberg
Keyword(s):  
Leaf Shape ◽  
Morphological Characters ◽  
Clonal Structure ◽  
Shape Variation ◽  
Canonical Variates Analysis ◽  
Hierarchical Structuring ◽  
Canonical Variates ◽  
Self Fertilization ◽  
The Mean ◽  
A Site

Data from isozyme and leaf shape variation are combined to explore the clonal structure at a site where hybridization between Sphagnum rubellum and Sphagnum capillifolium was previously indicated. Shoots of both species were sampled at 10-cm intervals along seven transects across different hummocks. Allelic data from 13 enzyme systems revealed 22 multilocus genotypes representing different clones, 18 being S. capillifolium and 4 being S. rubellum. The mean ± SE and maximum clonal length were 35 ± 8 cm and 160 cm, respectively. The sets of alleles found in the progeny of S. capillifolium were identical to the maternal complement of alleles in 78% of the material, indicating either self-fertilization or fertilization by a male with the same set of alleles at the screened loci. Outcrossing was detected in six cases. Patterns of differentiation and the hierarchical structuring of diversity among species, transects, and clones were analysed with canonical variates analysis using stem-leaf characters. A stronger relative differentiation was found between transects than between species. Clones identified by electrophoresis were usually morphologically well defined. Hybridization was indicated by morphological characters, occasional misplaced alleles, and signs of developmental instability. Keywords: allozymes, computerized image analysis, breeding system, clonal structure, Sphagnum rubellum, Sphagnum capillifolium.

A multivariate study of morphometric variation in species of the ciliate genus Colpoda (Ciliophora: Colpodida)

1983 ◽  
Vol 61 (2) ◽  
pp. 307-316 ◽  
Author(s):  
Denis H. Lynn ◽  
Jay R. Malcolm
Keyword(s):  
Morphological Characters ◽  
Multivariate Statistical Methods ◽  
Multivariate Statistical ◽  
Morphometric Variation ◽  
Canonical Variates Analysis ◽  
Multivariate Study ◽  
Single Character ◽  
Length Range ◽  
Canonical Variates ◽  
Left And Right

Univariate and multivariate statistical methods were used to study morphometric variation of 19 clones from eight species of the ciliate genus Colpoda. No single character could provide complete discrimination of all species. However, results of canonical variates analysis demonstrated that some morphological characters, which are considered important by taxonomists, do provide for maximum discrimination among the species. These characters include left and right keel kinety number, incurrent and excurrent canal kinety number, and vestibular kinety number. The clones in the somatic length range of 44–70 μm are apparently more difficult to distinguish by morphometric criteria.

scholarly journals Size-related Change in the Visual Resolution of Sunfish (Lepomis spp.)

1994 ◽  
Vol 51 (9) ◽  
pp. 2017-2026 ◽  
Author(s):  
William E. Walton ◽  
Stephen S. Easter Jr. ◽  
Celeste Malinoski ◽  
Nelson G. Hairston Jr.
Keyword(s):  
Body Size ◽  
Standard Length ◽  
Resolving Power ◽  
Pelagic Zone ◽  
Volume Increase ◽  
Fish Size ◽  
Visual Resolution ◽  
Search Volume ◽  
The Mean

Visual resolution of juvenile sunfish (Lepomis spp.) (8–33 mm standard length (SL)), although extremely poor in comparison with the larger individuals (38–160 mm SL) used in previous studies, improves rapidly as they grow. Histologically and behaviorally determined (mean reaction angle) visual angles of fish between 10 and 33 mm SL decrease by approximately 50 and 100 minutes of arc, respectively, and decline non-linearly with increasing fish size. Behaviorally determined visual resolution of juvenile sunfish based on maximum location distance (MLD) is equivalent to that calculated from intercone spacing. The mean reaction angle used in previous studies may have underestimated behavioral visual resolution of larger (> 38 mm SL) sunfish by approximately 30%. Visual volume and search volume increase by nearly three orders of magnitude in sunfish between 8 and 50 mm SL. After sunfish exceed 50 mm SL (when they can safely return to the pelagic zone), visual resolution increases comparatively slowly as body size increases. Our results suggest that the size-related change in behavioral visual resolution in sunfish is influenced by other factors in addition to the growth-related changes in the resolving power of the retina.

Can morphological characters be used to identify the pond-reared offspring of wild Chinese mitten crabs, Eriocheir sinensis, from different basins?

Crustaceana ◽  
2019 ◽  
Vol 92 (8) ◽  
pp. 957-978
Author(s):  
Xiaodong Jiang ◽  
Xugan Wu ◽  
Haining Wang ◽  
Yuhong Yang ◽  
Yongxu Cheng
Keyword(s):  
Morphological Difference ◽  
Principal Component ◽  
Morphological Characters ◽  
Eriocheir Sinensis ◽  
Stepwise Discriminant Analysis ◽  
Chinese Mitten Crab ◽  
Artificial Culture ◽  
Mitten Crab ◽  
Mitten Crabs ◽  
Morphological Differences

Abstract Although morphology is always used to distinguish wild Chinese mitten crab (Eriocheir sinensis) populations, whether morphology could be used to identify the pond-reared offspring of wild E. sinensis populations has remained unclear. This study was undertaken to examine the morphological difference of wild E. sinensis (G0) from the Yangtze River (YR), Huang River (HR) and Liao River (LR) as well as their pond-reared offspring (G1). The results showed that: (1) The amount of significantly different parameters of three G1 populations was evidently less than that of three G0 populations; (2) G0 and G1 individuals of each population were clearly separated by principal component analysis, furthermore, three G0 populations were clearly separated while three G1 populations were not well distinguished from each other; (3) discrimination accuracy of G1 individuals in stepwise discriminant analysis was obviously lower than that of G1 populations; (4) G0 and G1 populations were clustered into two separate clusters in the cluster analysis. In conclusion, morphological differences between wild E. sinensis populations had disappeared after one generation of artificial culture, and morphology thus probably cannot be used to distinguish the pond-reared offspring originated from three wild E. sinensis populations.

Molecular and morphological characterisation of Laimaphelenchus spiflatus n. sp. (Nematoda: Aphelenchoididae) from China

Nematology ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. 843-853
Author(s):  
Jianfeng Gu ◽  
Munawar Maria ◽  
Yiwu Fang ◽  
Xianfeng Chen ◽  
Lele Liu
Keyword(s):  
New Species ◽  
Body Size ◽  
Phylogenetic Analyses ◽  
Morphological Characters ◽  
The Other ◽  
Morphometric Data ◽  
Lateral Field ◽  
Chinese Pine ◽  
Lateral Lines ◽  
Genomic Regions

Summary Laimaphelenchus spiflatus n. sp. isolated from declining Chinese pine, Pinus tabuliformis, is described and illustrated. The new species can be characterised by its relatively long body size of 1150 ± 108 (976-1437) μm for females and 1092 ± 78.6 (905-1235) μm for males, lateral field with four lines, females with a long vulval flap, and tail conoid, slightly ventrally curved and ending in a stalk having 8-12 projections when observed with SEM. Males are common, with 27.3 (23.4-28.8) μm long spicules having blunt (not well-developed) condylus and rostrum and truncate simple distal tip, and four caudal papillae. By having a vulval flap, four lateral lines and tail end with a stalk (without four tubercles), the new species comes close to L. preissii, L. simlaensis, and L. unituberculus, but can be differentiated from them by morphological characters and morphometric data. In phylogenetic analyses using near full length 18S and D2-D3 expansion segments of 28S rDNA, Laimaphelenchus spiflatus n. sp. appeared as an independent lineage separated from the other Laimaphelenchus spp. that are currently sequenced for their aforementioned genomic regions.

scholarly journals Effects of Stimulus Shape on Visual Evoked Potentials

1978 ◽  
Vol 5 (3) ◽  
pp. 313-319 ◽  
Author(s):  
Sherrill J. Purves ◽  
Morton D. Low
Keyword(s):  
Stepwise Discriminant Analysis ◽  
Wave Form ◽  
Analysis Program ◽  
Single Trial ◽  
Discriminant Functions ◽  
Visual Evoked Responses ◽  
Negative Peak ◽  
Spatial Frequencies ◽  
Stimulus Shape ◽  
Visual Evoked

SUMMARY:Visual evoked responses (VER) to four geometric shapes (a square, circle, el and omega) were recorded from multiple scalp locations in twelve subjects. Significant differences were found between the occipital VERs to the square and el and between the VERs to the circle and omega. Consistent differences could not be demonstrated between the responses to the square and circle or to the el and omega.The differences between the responses were quantified by three different methods, including measurement of peak latencies and amplitudes, computation of a ratio index called λ, and the performance of discriminant functions derived by Stepwise Discriminant Analysis Program (SWDA) in classifying other single trial responses. The amplitudes (but not the latencies) of a negative peak at approximately 150 msec, and a positive one at 220 msec, latency were found to be different in the pairs of shapes described. SWDA was able to separate these same pairs and classify from 63 to 68% of new trials correctly. The latency points chosen to make up the discriminant functions correlated partly with the and components that were found to be significantly different in amplitude.It is suggested that the VER differences in the earlier part of the wave-form are related to the physical properties of the stimuli, including the contrast densities in the central 1.5° of the visual field and/'or the spatial frequencies contained in the stimuli. Differences demonstrated in later parts of the VERs may reflect differences in symbolic meaning of the stimuli.

Geographic variation in body size of American mink ( Mustela vison ) / Variation géographique de la taille du corps chez le vison d'Amérique ( Mustela vison )

Mammalia ◽  
2006 ◽  
Vol 70 (1-2) ◽  
Author(s):  
Richard T. Stevens ◽  
Michael L. Kennedy
Keyword(s):  
Body Size ◽  
American Mink ◽  
Size Variation ◽  
Mustela Vison ◽  
Morphological Characters ◽  
Geographic Proximity ◽  
Multivariate Statistical ◽  
Components Analysis ◽  
Individual Variables ◽  
Variation Géographique

AbstractSpatial variation in 26 morphological characters of American mink ( Mustela vison ) from 35 localities in North America was investigated using univariate and multivariate statistical analyses. Localities were chosen based on watersheds, and it was hypothesized that high levels of gene flow in minks would prevent partitioning of body size variation within watersheds. All 26 characters in males and 25 of 26 in females exhibited significant interlocality variation. The patterns of variation in body size resulting from principal components analysis indicated that, for both sexes, minks were largest in Alaska, Manitoba, and Alberta; smallest minks were found in Florida and Quebec. There did not appear to be a relationship between body size and geographic proximity. Environmental factors collectively were found to be related to body size, although individual variables were not typically significant. Of 16 environmental variables examined, only longitude was correlated with body size in both sexes, with largest minks in the west and smallest in the east. Latitude was also correlated with body size in females. It was concluded that variation in body size of mink was likely the result of more than one factor that includes both biotic and abiotic features.

A multivariate approach to plant mineral nutrition: dose–response relationships and nutrient dominance in factorial experiments

1985 ◽  
Vol 63 (12) ◽  
pp. 2138-2143 ◽  
Author(s):  
G. R. Shaver ◽  
M. J. Lechowicz
Keyword(s):  
Dose Response ◽  
Nutrient Content ◽  
N Fertilization ◽  
Mineral Elements ◽  
P Fertilization ◽  
Canonical Variates Analysis ◽  
Canonical Variates ◽  
Low Levels ◽  
High Fertilization ◽  
K Fertilization

Canonical variates analysis was used to compare the effects of fertilization on the concentrations of five mineral elements (N, P, K, Ca, and Mg) in young shoot tissues of six tundra plant species of three different growth forms. There were two specific objectives: (i) to determine whether it was possible to describe meaningful dose–response relationships in a multivariate response to fertilization, and (ii) to determine the multivariate effect of N plus P fertilization in comparison with the effects of N or P added alone. The results showed that low levels of N–P–K fertilization caused a shift in multivariate nutrient content that was intermediate between the control values and the shift caused by high fertilization, and in the same direction as the latter. In a June harvest, the effect of N plus P fertilization was very similar to the effect of N fertilization alone. However, in August the N plus P effect was dominated by the response to P alone. In all of the analyses, the fundamental similarities and differences among unfertilized plants of each species and growth form were maintained under fertilization.

Numerical taxonomy contributes to delimitation of Iranian and Turkish Hesperis L. (Brassicaceae) species

Phytotaxa ◽  
2018 ◽  
Vol 367 (2) ◽  
pp. 101 ◽  
Author(s):  
ATENA ESLAMI FAROUJI ◽  
HAMED KHODAYARI ◽  
MOSTAFA ASSADI ◽  
BARIŞ ÖZÜDOĞRU ◽  
ÖZLEM ÇETIN ◽  
...  
Keyword(s):  
Distance Matrix ◽  
Morphological Characters ◽  
Resolving Power ◽  
Group Method ◽  
Morphological Descriptors ◽  
Operational Taxonomic Units ◽  
Pair Group ◽  
Species Circumscription ◽  
Taxonomic Descriptions ◽  
Brassicaceae Species

Taxonomic descriptions of Iranian and Turkish Hesperis (Brassicaceae) species are generally insufficient and partly incomplete, which makes the species delimitation ambiguous. In order to clarify species circumscription, we scored 57 morphological descriptors (MDs) in 121 operational taxonomic units (OTUs) of Hesperis from Iran and Turkey and performed a multivariate analysis. The dendrogram was created from Gower’s distance matrix using Unweighted Pair Group Method with arithmetic mean (UPGMA) algorithm. The dendrogram clearly separates the 121 OTUs of Hesperis into five main phenons, which significantly deviate from the classical taxonomic treatment (sectional assignments) of the genus. Similar distinct delineation among the five phenons was revealed by a Principal Coordinate Analysis (PCoA), highlighting the resolving power of the multivariate analyses of quantitative and qualitative morphological characters. While there were significant variations among the OTUs for 57 MDs, the most distinctive morphological descriptors delimiting the phenons were estimated to be fruit, petal, stem, and leaf by a de-trended correspondence analysis (DCA). We also present a comparative discussion between the classical taxonomy and the delimitation of taxa revealed in our study.

A new skink fauna from Caribbean islands (Squamata, Mabuyidae, Mabuyinae)

Zootaxa ◽  
2012 ◽  
Vol 3288 (1) ◽  
pp. 1 ◽  
Author(s):  
S. BLAIR HEDGES ◽  
CAITLIN E. CONN
Keyword(s):  
Body Size ◽  
South America ◽  
Reproductive Traits ◽  
Morphological Characters ◽  
Critically Endangered ◽  
Glacial Cycles ◽  
Critically Endangered Species ◽  
Caribbean Islands ◽  
Island Species ◽  
Degree Of Convergence

Neotropical skinks are unique among lizards and other vertebrates in their degree of convergence, in reproductive traits,with eutherian mammals. They have also been famously difficult to classify into species, largely because of a conservativebody plan and paucity of conventional diagnostic characters. Currently there are 26 recognized species, six of which occuronly on Caribbean islands. All are placed in a single genus, Mabuya. We conducted a systematic revision of Neotropicalskinks using both conventional and unconventional morphological characters, supplemented by DNA sequence analyses.We define 61 species grouped into 16 clades, recognized here as genera. They include three available generic names(Copeoglossum, Mabuya, and Spondylurus) and 13 new genera: Alinea gen. nov., Aspronema gen. nov., Brasiliscincusgen. nov., Capitellum gen. nov., Exila gen. nov., Manciola gen. nov., Maracaiba gen. nov., Marisora gen. nov., Noto-mabuya gen. nov., Orosaura gen. nov., Panopa gen. nov., Psychosaura gen. nov., and Varzea gen. nov. These 16 generaof skinks form a monophyletic group and are placed in the Subfamily Mabuyinae of the skink Family Mabuyidae. Sixother skink families are recognized: Acontidae, Egerniidae, Eugongylidae, Lygosomidae, Scincidae, and Sphenomorphi-dae. We describe three new subfamilies of Mabuyidae: Chioniniinae subfam. nov., Dasiinae subfam. nov., and Trachyl-epidinae subfam. nov. We describe 24 new species of mabuyines: Capitellum mariagalantae sp. nov., Capitellumparvicruzae sp. nov., Copeoglossum aurae sp. nov., Copeoglossum margaritae sp. nov., Copeoglossum redondae sp.nov., Mabuya cochonae sp. nov., Mabuya desiradae sp. nov., Mabuya grandisterrae sp. nov., Mabuya guadeloupae sp.nov., Mabuya hispaniolae sp. nov., Mabuya montserratae sp. nov., Marisora aurulae sp. nov., Marisora magnacornaesp. nov., Marisora roatanae sp. nov., Spondylurus anegadae sp. nov., Spondylurus culebrae sp. nov., Spondylurus caico-sae sp. nov., Spondylurus haitiae sp. nov., Spondylurus magnacruzae sp. nov., Spondylurus martinae sp. nov., Spondy-lurus monae sp. nov., Spondylurus monitae sp. nov., Spondylurus powelli sp. nov., and Spondylurus turksae sp. nov. Wealso resurrect 10 species from synonymies: Alinea lanceolata comb. nov., Alinea luciae comb. nov., Capitellum metalli-cum comb. nov., Mabuya dominicana, Marisora alliacea comb. nov., Marisora brachypoda comb. nov., Spondylurusfulgidus comb. nov., Spondylurus nitidus comb. nov., Spondylurus semitaeniatus comb. nov., and Spondylurus spilonotuscomb. nov. Of the 61 total species of mabuyine skinks, 39 occur on Caribbean islands, 38 are endemic to those islands,and 33 of those occur in the West Indies. Most species on Caribbean islands are allopatric, single-island endemics, al-though three species are known from Hispaniola, three from St. Thomas, and two from Culebra, St. Croix, Salt Island,Martinique, the southern Lesser Antilles, Trinidad, and Tobago. Co-occurring species typically differ in body size and be-long to different genera. Three ecomorphs are described to account for associations of ecology and morphology: terrestri-al, scansorial, and cryptozoic. Parturition occurs at the transition between the dry and wet seasons, and the number ofyoung (1–7) is correlated with body size and taxonomic group. Molecular phylogenies indicate the presence of many un-named species in Middle and South America. A molecular timetree shows that mabuyines dispersed from Africa to SouthAmerica 18 (25–9) million years ago, and that diversification occurred initially in South America but soon led to coloni-zation of Caribbean islands and Middle America. The six genera present on Caribbean islands each represent separate dis-persals, over water, from the mainland during the last 10 million years. Considerable dispersal and speciation alsooccurred on and among Caribbean islands, probably enhanced by Pleistocene glacial cycles and their concomitant sea lev-el changes. Based on IUCN Redlist criteria, all of the 38 endemic Caribbean island species are threatened with extinction.Twenty-seven species (71%) are Critically Endangered, six species (16%) are Endangered, and five species (13%) are Vul-nerable. Sixteen of the Critically Endangered species are extinct, or possibly extinct, because of human activities duringthe last two centuries. Several of the surviving species are near extinction and in need of immediate protection. Analysisof collection records indicates that the decline or loss of 14 skink species can be attributed to predation by the Small IndianMongoose. That invasive predator was introduced as a biological control of rats in sugar cane fields in the late nineteenthcentury (1872–1900), immediately resulting in a mass extinction of skinks and other reptiles. The ground-dwelling and diurnal habits of skinks have made them particularly susceptible to mongoose predation.

Sign in / Sign up

Export Citation Format

Share Document