Comparative susceptibility of conifers to knobcone pine dwarf mistletoe

Analysis of morphological characters of Arceuthobium apachecum and A. blumeri indicates there are several geographically consistent differences between these taxa, which supports their current classification at the specific level. Shoot height and perianth lobe number exhibited considerable geographic variation, and some morphological characters examined were continuous. Peak flowering and seed dispersal periods for these species differed slightly Altitudinal, seasonal, and latitudinal variations in flowering and seed dispersal were detected and may be responsible for the differences in phenology between these taxa.     

Taxonomic studies of dwarf mistletoes ( Arceuthobium ssp.) parasitizing Pinus strobiformis

Analysis of morphological characters of Arceuthobium apachecum and A. blumeri indicates there are several geographically consistent differences between these taxa, which supports their current classification at the specific level. Shoot height and perianth lobe number exhibited considerable geographic variation, and some morphological characters examined were continuous. Peak flowering and seed dispersal periods for these species differed slightly Altitudinal, seasonal, and latitudinal variations in flowering and seed dispersal were detected and may be responsible for the differences in phenology between these taxa.     

Ancestrular morphology in cyclostome bryozoans and the quest for phylogenetically informative skeletal characters

Cyclostomes are an ancient order of bryozoans with more than 500 living species. Traditionally, cyclostome taxonomy has depended almost entirely on characters of the calcareous skeletons of mature colonies. However, the taxonomic distribution of these characters is largely incongruent with well-supported molecular phylogenetic trees, implying the need for major revisions if cyclostome taxonomy is to reflect phylogeny. While far more taxa must be sequenced to ascertain their molecular relationships, there is also a need to discover morphological characters that can be used to support molecular clades, not least to allow these clades to be inferred among fossil cyclostomes for which molecular data will never be available. Here we survey the skeletal morphology of the first-formed part of the skeleton – the protoecium of the founding zooid (ancestrula) – in a variety of Recent and well-preserved fossil cyclostomes, motivated by the recent discovery of a morphologically disparate molecular clade that can be distinguished by protoecial characters. The distribution of pseudopores on the protoecium is shown to vary between species, with eight patterns recognizable, offering a new source of skeletal characters in both living and fossil taxa. However, the patterns seem not to be fully congruent with the cyclostome molecular tree and more data and analyses are required before these patterns can be used to recognize cyclostome clades.     

On the taxonomic status of Eriogonum robustum (Polygonaceae), a rare endemic in western Nevada

Evidence from the morphology, genetics, and biogeography of a rare endemic from western Nevada, Erigonum robustum , is presented to determine the most accurate taxonomic classification. Previous authors have classified E. robustrum Greene both as a species and as a variety E. lobbii Torrey & Gray. However, results of a morphometric comparison for 9 characters establish that significant morphological differentiation exists between E. robustum and E. lobbii . In addition, results of a genetic study using protein electrophoresis indicated that genetic differentiation may exist between these 2 taxa. Furthermore, the 2 taxa are geographically, ecologically, and reproductively isolated. Finally, the selective pressures that act on E. robustum in a narrowly restricted cold-desert environment are different from those that act on E. lobbii in subalpine environment. Thus, all available data support a species-level taxonomic classification for E. robustum .     

On the new goby,Ctenogobius veliensis (Teleostei: Gobiidae) from the South-West coast of India

Summary

Ctenogobius veliensis, a new species of gobiid fish is described from the South-West coast of India. The characters of the fish conform to those of the genus Ctenogobius Gill but differ markedly from those of other recorded species of the genus. Apart from the usual, external morphological, morphometric and metistic characters, several other features such as the cephalic-lateralis system, skeletal features and morphology of the alimentary canal are also studied and have been found to be of significance for identifying the species. The fish shows distinct sexual dimorphism in many features.     

Genetic differentiation of rare and common varieties of Eriogonum shockleyi (Polygonaceae) in Idaho using ISSR variability

Idaho populations of Eriogonum shockleyi are divided taxonomically into 2 varieties: E. shockleyi var. packardae , which is endemic to Idaho, and the typical variety, which is widespread in the western United States. Recent morphological investigations of E. shockleyi in Idaho have identified potentially reliable morphological characters for field identification of the subspecific taxa. This paper investigates the genetic basis for the separation of the 2 varieties of E. shockleyi using inter simple-sequence repeats (ISSR) markers. Although we found some morphological differences between the populations that correlated with the 2 varieties, we identified no molecular markers in this study to distinguish between them. Morphological measurements obtained in the field indicate that although a population may have an overall average morphology that defines the variety, some individuals in nearly all populations have putative diagnostic characters that define the other variety. The morphological characters used to distinguish the 2 varieties are most likely the result of environmental variability and could result from differences in precipitation and soil water retention. Alternatively, high levels of outcrossing through pollen flow could be obscuring selection for morphological characters at particular sites.     

Morphometric and molecular variation in mountain catfishes (Amphiliidae: Amphilius) in Guinea,West Africa

Species of the genus Amphilius are small benthic catfishes that occur throughout tropical Africa and are abundant in the mountain streams of the Fouta Djalon region in Guinea, West Africa. During a 2003 expedition to the area, numerous amphiliid catfish were collected and initial observations revealed a large amount of morphological variation across the sampled basins. These specimens were subjected to a geometric morphometric analysis and standard morphometric analysis. Cytochrome b gene sequences were also obtained and compared among populations. These analyses resulted in the discovery of multiple cryptic taxa within two recognized species, Amphilius platychir and Amphilius rheophilus. The discovery of these taxa is compared with other recent discoveries from the area.     

Morphology and taxonomy of Klamath Basin suckers (Catostomidae)

We examined morphology of 4 sucker species (Catostomidae) from Klamath and Rogue River basins, Oregon and California. Different pairs of these species have been suspected of hybridizing, and field biologists have experienced difficulty identifying individuals in some areas. The suite of morphological characters used for initial identification was poorly supported by other morphometric characters but well supported by meristic characters, especially when analyses were restricted geographically. In some species sexual dimorphism was evident, with males having longer pectoral fins and females having longer pre-anal counts and measurements. Each species showed geographic differentiation, either between the Lost River subbasin and other Klamath subbasins or between Klamath and Rogue basins. Classification was most difficult for Catostomus snyderi , which was frequently misclassified as all other species, but especially as Chasmistes brevirostris . Despite this, the 2 species are ecologically segregated in the upper subbasins with lake-spawning Ch. brevirostris spatially segregated and river-spawning Ch. brevirostris temporally segregated from river-spawning C. snyderi . We discuss the possibility that a large-headed, thin-lipped species has become extinct in Upper Klamath Lake and alternatively suggest that the form could represent an ecophenotype of Ch. brevirostris that is no longer produced in hypereutrophic Upper Klamath Lake.     

Identity of Mertensia oblongifolia (Nutt.) G. Don (Boraginaceae) and its allies in western North America

The current status of Mertensia oblongifolia (Nutt.) G. Don and its allied taxa is surveyed. On the bases of continuously coherent morphological characters and/or regionally correlated variations, more than 30 taxa, including species, subspecies, varieties, and 1 forma, previously considered different from M. oblongifolia , are now placed under synonymy of this species. Those taxa currently known as M. fusiformis Greene, M. bakeri Greene, and M. bakeri var. osterhoutii Williams are among the new synonyms. Typification, taxonomy, and morphological problems of M. oblongifolia are discussed.     

Fossil history of Notiosorex (Soricomorpha: Soricidae) shrews with descriptions of new fossil species

Notiosorex shrews (Soricomorpha: Soricidae) have a fossil history that extends to the Miocene (i.e., mid-Hemphillian). In the intervening 6.69 million years, N. repenningi, N. jacksoni, and what heretofore was considered N. crawfordi existed with varying degrees of overlap in occurrence timewise and in geographic distribution in areas of the southwestern United States and northern Mexico. Examination of unusually small fossil specimens of Notiosorex indicated the presence of another species referable to this genus present in late Pleistocene- (i.e., early Wisconsinan) to Holocene-aged deposits. Based on statistical analyses, these specimens were as distinct from any of the other fossil or extant species of Notiosorex as any other pair of species within the genus. I referred these specimens to the new species N. harrisi. Analyses also indicted fossils heretofore considered N. crawfordi were equally distinct from other forms of Notiosorex. I referred them to the new species N. dalquesti. Individuals referred to the fossil species of Notiosorex range in size from the smaller N. harrisi, to N. dalquesti, to N. jacksoni, to the larger N. repenningi. This size differential could be related to changing climatic conditions with the concomitant ecological succession that occurred, which provided a driving force for speciation within the genus. The changing climate and unique morphological and physiological adaptations allowed fossil taxa of Notiosorex to expand their distributions into areas subsequently less suitable for other forms of shrews. Present-day notiosoricini shrews occur throughout much of the southwestern United States and northern Mexico in a variety of habitats in association with rough, rocky terrain. Thus, if climate, even indirectly, was the driving force for speciation among fossil taxa of Notiosorex, other forces must have acted on the extant species N. cockrumi, N. crawfordi, N. evotis, and N. villai.     

Morphometric differentiation between two sympatric Macrobrachium Bates, 1868 shrimps (Crustacea: Decapoda: Palaemonidae) in West‐African rivers

A comparative morphometric study was performed on two species of shrimps, Macrobrachium macrobrachion (Herklots, 1851) and Macrobrachium vollenhovenii (Herklots, 1857). In total, 714 specimens (563 males and 151 females) originating from four rivers in Ivory Coast were analysed. The morphometry was carried out on 33 measurements; seven meristic and four morphological characters and ratios were calculated from the measurements. Data were analysed using univariate, bivariate and multivariate statistics. Meristic and morphological characters did not allow separation of distinct species. However, metric variables and ratios clearly discriminated the two species. The characters (merus/palm, carpus/palm, palm width/palm length, carpus width/carpus length, palm width) related to the form and the size of second pereiopods could be used for the discrimination of both species. This study, by allowing accurate identification of these species, will facilitate future research.     

Evolutionary differentiation within the northern Great Basin pocket gopher, Thomomys townsendii I. Morphological variation

Geographic and nongeographic variation in morphology was examined in Thomomys townsendii . A univariate analysis of external and cranial characters from a large population sample (66 adults; fusion of cranial sutures used as aging criteria) was used to assess variation among three adult age classes and between sexes. Only minor variation is apparent among age classes; however, sexual dimorphism is pronounced. Univariate and multivariate techniques were used to analyze external and cranial measurements and pelage characters for adults throughout the species range. These analyses show little to support the seven subspecific designations recognized by Davis (1937). The general pattern is one of homogeneity throughout the range of Thomomys townsendii . With the possible exception of T. t. nevadensis samples, current subspecies are not defined as morphological units. In fact, differentiation is found among populations within some subspecies. The most apparent pattern seen in these analyses is the divergence between the Humboldt River (including Honey Lake Valley samples) and Snake River systems. These results will be considered with those of a companion paper on the genetic variation in this species to more adequately assess the patterns of differentiation in Thomomys townsendii .     

Evolutionary differentiation within the northern Great Basin pocket gopher, Thomomys townsendii II. Genetic variation and biogeographic considerations

Geographic and nongeographic variation in morphology was examined in Thomomys townsendii . A univariate analysis of external and cranial characters from a large population sample (66 adults; fusion of cranial sutures used as aging criteria) was used to assess variation among three adult age classes and between sexes. Only minor variation is apparent among age classes; however, sexual dimorphism is pronounced. Univariate and multivariate techniques were used to analyze external and cranial measurements and pelage characters for adults throughout the species range. These analyses show little to support the seven subspecific designations recognized by Davis (1937). The general pattern is one of homogeneity throughout the range of Thomomys townsendii . With the possible exception of T. t. nevadensis samples, current subspecies are not defined as morphological units. In fact, differentiation is found among populations within some subspecies. The most apparent pattern seen in these analyses is the divergence between the Humboldt River (including Honey Lake Valley samples) and Snake River systems. These results will be considered with those of a companion paper on the genetic variation in this species to more adequately assess the patterns of differentiation in Thomomys townsendii .     

Heleobia maltzani (Westerlund, 1886) (Caenogastropoda: Truncatelloidea: Cochliopidae) from Crete and species-level diversity of Heleobia Stimpson, 1865 in Europe

Morphological characters and partial cytochrome oxidase (COI) DNA sequences were used to investigate intra- and interpopulation differences among three Cretan brackish-water populations of Heleobia maltzani snails. The morphology of male and female reproductive organs of H. maltzani did not differ within studied populations or in comparison with closely related species. In contrast, analysis of shell morphology revealed substantial variation not supported by the genetic data. Genetics results showed surprisingly low differentiation between all Cretan populations and also mainland populations of Heleobia. They also showed that H. maltzani is conspecific with four other European species of Heleobia, thus implying that there is only one species of brackish-water Heleobia in Europe. Such a low level of genotypic differentiation is unusual for typical island species and is most probably the consequence of recent colonization of Crete. Possible scenarios of such processes are discussed.     

Improving knowledge of the cyclorrhaphan larva (Diptera)

A significant factor in the evolution of the Cyclorrhapha (Diptera), the most biodiverse of higher dipteran taxa, is the larva. The larva also has wide-ranging trophic and environmental relationships, including positive and negative impacts on human health and wealth. Despite its importance, the larva is neglected and a low proportion of species are known in this stage. In this paper, factors contributing to larval neglect are reviewed, including: poor attitudes leading to cycles of neglect and shallow treatment; taxonomy that uses adult not larval stages; lack of material in collections; rearing barriers, and presumptions of morphological similarity suggesting that characters will be problematic to acquire and analyse. Neglect is pervasive and affects many subjects; those considered here are: species inventories and rarity assessments for biodiversity and conservation, in which larvae are usually ignored although they can be more cost-effective to sample and a richer source of environmental data; determining larval feeding modes where controversies due to conflicting evidence persist unresolved; and reliance on a limited pool of increasingly old publications whose data are repeated rather than tested and updated with new research. In an attempt to reinvigorate interest, which is the main aim of this paper, poorly assessed larval features possibly significant to cyclorrhaphan diversification are also considered. These include: change facilitated by independently evolvable modules; rapid change enabled by labile trophic morphology; shifts between saprophagy and phytophagy due to opportunities provided by angiosperm evolution; and enhanced adaptive potential resulting in derived more than basal taxa developing adaptations that enable access to new and little used resources. Apart from the need to rear more larvae, a major conclusion from this review is that knowledge will improve when the movement capabilities of larvae are used to inform morphological and taxonomic analyses.     

Sibling species in the marine pollution indicator genus Pontonema Leidy (Nematoda: Oncholaimidae), with a description of P. mediterranea sp. nov.

Species of the marine nematode genus Pontonema have been found to dominate the macrobenthos under abnormally high conditions of particulate organic enrichment. Populations from organically enriched habitats in six localities (Kiel fjord, Germany; the Garroch Head sewage-sludge dump ground in the Firth of Clyde, Scotland; Cornelian Bay, N.E. England; the Tyne estuary, N.E. England; Sete, N.W. Mediterranean, France; Blanes Bay, N.W. Mediterranean, Spain) have been compared. Multivariate analyses of 16 morphometric characters in males, and 13 in females, shows that each population is significantly different morphologically from every other population. However, there is morphological overlap between the populations, and it is considered pragmatic to recognize three species in this group, based on a few stable morphological characters: P. vulgare (Bastian, 1865) from the Baltic, P. alaeospicula Bett and Moore 1988 from the UK sites, and P. mediterranea sp. nov. from the Mediterranean. P. mediterranea sp. nov. is described. The species were not found to have established sympatry in this study, unlike many other opportunistic taxa from organically enriched habitats, and the significance of this is discussed.     

Morphology and spatial constraints in a dorso‐ventrally flattened skull,with a revised species description of Platyallabes tihoni (Poll, 1944)

This study details the morphology of Platyallabes tihoni (Poll, ) as part of a complete revision of the anguilliform clariids. The overall body form of air‐breathing clariids ranges from fusiform to anguilliform genera (Boulenger ; Pellegrin ). Although P. tihoni has the typical external morphological features of other elongate clariids, this study shows that it occupies an intermediate position between fusiform and anguilliform taxa with regards to its cranial and postcranial morphology. The main morphological similarities of anguilliform species are a narrow skull roof with a high level of interdigitation between the bones, the reduced canal bones, a connection between the neurocranium and suspensorium via several processes, an extended tooth patch on the lower jaw, and the hypertrophied jaw muscle complex. Shared features typical for the fusiform species are a low coronoid process on the lower jaw and the posteroventral orientation of the opercular process on the hyomandibula. Platyallabes tihoni shows a series of unique features: an anterior fontanel situated entirely between the frontals, two tooth plates on the prevomer, a reduced height of the suspensorium, the absence of an anterior bony plate on the hyomandibula, a horizontal position of the sphenotic and pterotic, and a toothed entopterygoid. Many of these unique characters are linked to the spatial constraints associated with an extremely flattened skull in this species.     

Assessment of morphometric characters to delimit species of Apolpium Chamberlin, 1930 (Pseudoscorpiones,Olpiidae)

ABSTRACT

Pseudoscorpiones is a mesodiverse order of Arachnida, with more than 3600 described species in the world. Species delimitation is sometimes difficult due to the high variability of some characters, difficulty in finding informative and useful characters for species differentiation and the subjectivity of individual specialists. The aim of this work is to explore and to evaluate the role of morphometric characters in species delimitation within the genus Apolpium (Olpiidae). Measurements of 17 structures of 57 individuals were taken and their length/width ratios calculated. Cluster analyses, principal components analyses, discriminant function analyses and non-metric multidimensional scaling were carried out. The results showed low resolution for the number of species currently recognised in the genus. These results highlight the importance of looking for other morphological characters, and also for a more rigorous assessment of previously used characters for defining species.     

Morphology of ephemeral and persistent leaves of three subspecies of big sagebrush grown in a uniform environment

Measurements were made of morphological characteristics of ephemeral and persistent leaves of three subspecies of big sagebrush ( Artemisia tridentata Nutt.) grown in a uniform environment. No morphological feature clearly separated the subspecies. Genetic - environmental interactions on leaf morphology apparently reduce its value as a sole criterion for distinguishing the subspecies.