New Zealand's giant Collembola: New information on distribution and morphology for Holacanthella Börner, 1906 (Neanuridae: Uchidanurinae)

Abstract

The New Zealand collembolan fauna currently includes five described species of the striking endemic genus Holacanthella (springtails). Holacanthella species are saproxylic decomposers of cool temperate forest ecosystems, and they contribute to nutrient cycling of coarse woody debris. All species of the genus have the dorsal and lateral surfaces furnished with conspicuous red, orange, yellow or white digitations. They are among the largest Collembola known, with some individuals reaching 17 mm in length. We examined new material of the five species from throughout New Zealand, as well as existing museum material, to understand more fully their distributions. We provide an updated key to the five Holacanthella species and discuss the conservation of rare/range restricted species, and propose hypotheses to explain their distributions. One species, H. laterospinosa, is known only from Cuvier Island and the Coromandel Peninsula, North Island, but the distributions of the remaining four species appears to reflect the turbulent geological history of New Zealand during the Pliocene. Intraspecific variation in several gross morphological characters was observed in all species. We provide a comparison of characters with the other genera within the Uchidanurinae in order to characterise the genus more fully with respect to allied genera. Holacanthella species are particularly vulnerable to human‐mediated disturbance by forest modification because of their strict habitat requirements and low mobility, and we stress that conservation efforts should focus on protecting critical habitats for each species.     

On the necessity of an archetypal concept in morphology: With special reference to the concepts of “structure” and “homology”

Morphological elements, or structures, are sorted into four categories depending on their level of anatomical isolation and the presence or absence of intrinsically identifying characteristics. These four categories are used to highlight the difficulties with the concept of structure and our ability to identify or define structures. The analysis is extended to the concept of homology through a discussion of the methodological and philosophical problems of the current concept of homology. It is argued that homology is fundamentally a similarity based concept rather than a phylogenetic concept, and a proposal is put forth to return to a comparative context for homology. It is shown that for both the concepts of structure and homology ana priori assumption of stable underlying patterns (i.e. archetypes) is essential.     

Bellisotoma,a new genus of Isotomidae from North?America (Hexapoda,Collembola)

A new genus of Isotomidae, Bellisotoma gen. n., is described. The new genus is a member of the Proisotoma genus complex and is characterized by a combination of having a bidentate mucro with wide dorsal lamellae that join clearly before the end of mucronal axis without forming a tooth and one strong ventral rib with basal notch that articulates with dens; having abundant chaetotaxy on both faces of dens; and abundant tergal sensilla. Bellisotoma gen. n. shows a furcula adapted to a neustonic mode of life, and may be a Isotopenola-like derivative adapted to neustonic habitats. Subisotoma joycei Soto-Adames & Giordano, 2011 and Ballistura ewingi James, 1933 are transferred to the new genus.     

Fine structure of the ‘hindgut’ of the two-spotted spider mite,Tetranychus urticae,with special reference to origin and function

The ultrahistology of the hindgut of the spider miteTetranychus urticae is described, a new terminology of the histological portions, based on the presence and absence of cuticle, is presented, and functional characteristics are discussed.The alimentary canal of the spider mite consists of the cuticle-lined foregut (pharynx, esophagus, esophageal valve), a cuticle-free midgut, and a cuticle-lined hindgut with anal slit. The portions of the midgut are the ventriculus with three cranial and two caudal caeca, and the posterior midgut with two distinct cell types. Both portions are separated by a sphincter. The anterior lateral walls of the -shaped posterior midgut which terminates in the dorsal region of the ventriculus show histological variability. Cells are either asymmetrical with long apical projections (=typical transporting epithelium) or show resorptive characteristics and storage products (=resorptive epithelium). The dorsal and posterior lateral epithelium consists of flat glandular cells containing large granular secretion grana. It is suggested that these cells synthesize mucoid substances for the facilitation of excretion transport.The differentiation and function of the posterior midgut epithelium are discussed with respect to the formation of different elimination products.     

The spermatheca of the Dipsocoridae with special reference to the strange “loculus capsulae” in Harpagospecies (Heteroptera,Dipsocoromorpha)

The spermatheca of Dipsocoridae is described and compared in the three known genera of the family (Cryptostemma, Harpago n. stat. and Pachycoleus); it consists of three distinct parts: a long coiled duct including a short apically differentiated segment (pars intermedialis) of unknown function, a spherical seminal capsule, and a small bulb-shaped apical gland with a muscular pump at its base. The structure of the spermatheca remains very uniform in the family, especially the apical gland that is anatomically distinct from the seminal capsule and which seems to be an apomorphy for the whole Dipsocoromorpha. A recently discovered structure, named here the loculus capsulae, appears to exist only in the two known species of the genus Harpago. This internal cuticular structure is situated on the left side of the seventh tergite. It consists of two broad expansions, extending from the tergite and laterotergite respectively, which maintain the seminal capsule near the abdominal wall. This structure appears as a kind of supporting armature impeding the spherical seminal capsule from free movement in the abdominal cavity. The form and function of this strange structure are discussed in this paper.     

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.     

Establishment and characterization of HEPFT, a cell line derived from hepatoid carcinoma of the fallopian tube, with special reference to α-fetoprotein, lectin affinity and histogenesis

A cell line designated "HEPFT" was established from a human fallopian tubal hepatoid carcinoma. This line grew well without interruption for 13 months and was subcultivated over 35 times. The cells were spherical and polygonal in shape and showed neoplastic and pleomorphic features such as a bizarre aggregation of chromatin granules, an irregular thickening membrane and multiple large nucleoli. The cells formed epithelial colonies with a jigsaw puzzle-like arrangement and multilayering without contact inhibition. The cells contained moderate to abundant amounts of eosinophilic cytoplasm and were immunohistochemically positive for alpha-fetoprotein. The cells proliferated rapidly, and the population doubling time was about 45 h. The chromosome number showed a wide distribution of aneuploidy. The modal chromosome number was stable in the hyper triploid range and many marker chromosomes were observed. The culture cells produced bile and a large amount of lentil lectin-reactive alpha-fetoprotein. The recently developed bacterial artificial chromosome array comparative genomic hybridization facilitated detailed analysis with high resolution and sensitivity. Different profiles of genomic copy-number abnormalities were demonstrated in various chromosomal regions in HEPFT cells.     

Larval development and morphogenesis of the sea spider Pycnogonum litorale (Ström, 1762) and the tagmosis of the body of Pantopoda

Aspects of pantopod ontogeny have been known for a long time, but specific information is available for only a few species. Our account of the postembryonic development of Pycnogonum litorale is based on laboratory-reared individuals and SEM studies. We documented particularly all early developmental stages, with emphasis on morphogenetic changes of head structures and appendages. In P. litorale the protonymphal limbs, the chelicerae and two more uniramous legs, degenerate already during the larval phase; only the third one, the ovigers, reappears in male juveniles. Other Pantopoda vary in this aspect from retention of all three protonymphal appendages to their complete reduction, as in P. litorale. Accordingly, the two post-cheliceral larval appendages are separate legs in front of the walking legs in the adults, the ‘parapalps’ and the ‘ovigers’, but they do not occur in all pantopods. The scarcity of studies of the ontogeny of Pantopoda prevents us from a more conclusive picture, but our data are promising to state that additional such studies will increase the usability of ontogenetic data for a phylogenetic analysis of Pantopoda, the crown group of the Pycnogonida. We also discuss the phylogenetic implications of our data in the light of new information from Hox genes and developmental-biological data on body segmentation and tagmosis of the Chelicerata. These suggest the homology of chelicerae and antenn(ul)ae of other euarthropods. Accepting this, we conclude that the adult pycnogonid/pantopod head, the cephalosoma, corresponds to the euarthropod head and that the protonymph with three appendage-bearing segments may represent an even shorter, possibly phylogenetically older larval type than the euarthropod ‘head larva’ bearing four pairs of appendages. In further consequence, the fourth walking legs of Pycnogonida/Pantopoda should correspond to the first opisthosomal appendages, the chilaria, of euchelicerates. This implies that within Pycnogonida the post-prosomal region became compacted during evolution to a single leg-bearing segment plus a tubular end piece. Accordingly, neither the anterior nor the posterior functional boundaries of the walking-leg region correspond to the original tagma borders.     

Ostracods and the Holocene palaeolimnology of Lake Qarun, with special reference to past human–environment interactions in the Faiyum (Egypt)

We present an ostracod record covering the past two millennia from an 8.25-m core taken from Lake Qarun, in the Faiyum Depression of Egypt. The occurrence of ostracod species in the lake is controlled primarily by variations in solute composition, which are in turn related to shifts in catchment land use. At times when the Faiyum Depression supported thriving agriculture, lake water contained Na⁺–Cl^? brine, and Cyprideis torosa dominated the ostracod assemblage. When the Faiyum Depression experienced periods of environmental and economic decline, lake water contained Na⁺–HCO₃ ^? brine, and Limnocythere inopinata dominated. The relative abundance of other ostracod species provides additional information about past conditions in Lake Qarun including salinity and lake level changes. Overall, the ostracod assemblages provide evidence for human influences in the Faiyum, which extend back before instrumental or detailed observational records began.     

Embryonic development and hatching of chirocephalus diaphanus prévost (Crustacea: Anostraca) in nature

The embryonic development and hatching of C. diaphanus under natural conditions were investigated. Most of the embryonic development takes place during the dry period of the pond. Thus eggs are ready to hatch as soon as the pond is filled with rainwater.The pattern of the distribution of eggs on the bottom of the pond has a great value for the survival of the species. Adult females tend to lay their eggs mainly in the central parts of the pond.Department of Biology, University of Southampton     

Vegetation history of the Maharlou Lake basin (SW Iran) with special reference to the Achaemenid period (550–330 bc)

Vegetation History and Archaeobotany - This study presents the results of a palynological investigation on a sediment core from the seasonal and saline Lake Maharlou in the Zagros Mountains in...     

The production of the apterous and alate forms in the aphid Megoura viciae Buckton,with special reference to the rôle of crowding

Although high temperature suppresses the production of alate forms in Megoura, the most significant controlling factor is the degree of crowding. This has been studied by confining aphids in tubes before returning them to the host plant for progeny testing. Adult apterae crowded together in groups of ten for 24 hr produce successive batches of progeny containing alatae and apterae in varying proportions, the number of alatae tending to fall as parturition proceeds. Control aphids isolated in tubes for the same length of time produce only apterous daughters. Crowding effects are therefore due to interactions between the aphids themselves and are not caused by starvation. The response is maternal and begins to appear in the fourth instar. Younger larvae are insensitive.The development of the crowding response is related to the frequency of the encounters between aphids. This was shown by varying either the population density or the size of the container. However, two individuals are adequate to constitute a ‘crowd’, provided the volume of the ‘arena’ is not too great. The contacts must extend over several hours. Overcrowding tends to reduce the response intensity.The sensory mechanisms of the crowding response have been examined. Visual and olfactory stimulation, as well as the exchange of pheromones, can be excuded. Since contacts are required, the relevant sense is probably that of touch. The mechanoreceptors are doubtless the thick-walled articulated bristles on the legs, antennae, and body. Antennal amputation, which removes all the known chemosensilla, fails to abolish the response. Artificial tactile stimulation has so far failed to elicit alata-production. But a variety of alien insects, such as small cockroaches or the beetle Ptinus tectus, are efficient ‘aphid substitutes’. Insects that are too sluggish to provide many encounters are ineffective.Wing dimorphism is apparently controlled by a diffusible ‘alata-determiner’ liberated from the head of the parent. This agent seems partially to inhibit the secretory activity of the corpus allatum during the late prenatal and early postnatal periods of larval development. But the determination process, which decides the level of secretion, occupies only a few hours prior to birth.     

The effect of host species on growth and variability of Echinorhynchus salmonis Müller, 1784 (Acanthocephala: Echinorhynchidae), with special reference to the status of the genus

Summary The sex and age (as measured by length) of Echinorhynchus salmonis Müller, 1784 and the host species of this acanthocephalan considerably affected worm body form and size, as well as size of proboscis, proboscis hooks, proboscis receptacle, lemnisci, testes and cement glands. Linear regression analysis indicated that curves describing the growth pattern of these characters by worm length were significantly different as a function of host species. The larger worms recovered from bloater (Coregonus hoyi: Salmonidae) almost invariably showed higher regression coefficient compared to those from smelt (Osmerus mordax: Osmeridae) in all characters. Taxonomic implications of these findings are discussed. Abnormalities in body wall, proboscis hook orientation, lemnisci and cement gland ducts as well as variations in proboscis hook and cement gland numbers are reported, some for the first time. Findings from studies of cement gland pattern invalidate Petrochenko's (1956) splitting up of the genus into three: Echinorhynchus, Metechinorhynchus and Pseudoechinorhynchus. It is proposed that the designation of the last two genera as junior synynoms of the first be accepted. ac]19791205     

Ontogeny of the ventral nerve cord in malacostracan crustaceans: a common plan for neuronal development in Crustacea, Hexapoda and other Arthropoda?

This review sets out to summarize our current knowledge on the structural layout of the embryonic ventral nerve cord in decapod crustaceans and its development from stem cell to the mature structure. In Decapoda, neuronal stem cells, the neuroblasts, mostly originate from ectodermal stem cells, the ectoteloblast, via a defined lineage. The neuroblasts undergo repeated asymmetric division and generate ganglion mother cells. The ganglion mother cells later divide again to give birth to ganglion cells (neurons) and there is increasing evidence now that ganglion mother cells divide again not only once but repeatedly. Various other aspects of neuroblast proliferation such as their temporal patterns of mitotic activity and spatial arrangement as well as the relation of neurogenesis to the development of the segmental appendages and maturation of motor behaviors are described. The link between cell lineage and cell differentiation in Decapoda so far has only been established for the midline neuroblast. However, there are several other identified early differentiating neurons, the outgrowing neurites of which pioneer the axonal scaffold within the neuromeres of the ventral nerve cord. The maturation of identified neurons as examined by immunohistochemistry against their neurotransmitters or engrailed, is briefly described. These processes are compared to other Arthropoda (including Onychophora, Chelicerata, Diplopoda and Hexapoda) in order to shed light on variations and conserved motifs of the theme 'neurogenesis'. The question of a 'common plan for neuronal development' in the ventral nerve cords of Hexapoda and Crustacea is critically evaluated and the possibility of homologous neurons arising through divergent developmental pathways is discussed.     

A study of normal and regenerative growth in the pistol-crab,alpheus dentipes (Guèr.), with special reference to the phenomenon of chela reversal

Summary An analysis has been made of the normal growth of the thoracic appendages in the pistol-crab,Alpheus dentipes. The chelae are the only asymmetrical appendages and, within an extensive size range, the growth-coefficient of the large chela (crusher) is smaller than that of the small chela (nipper), even in the most rapidly growing dimensions of the segment containing the growth-centre.The partition coefficient for growth in certain dimensions of the chelae is not constant but is reduced progressively during the growthperiod, due (it is suggested) to the impracticability of maintaining the intensive heterogony developed during the early stages of growth.Regenerative growth of the chelae has been studied quantitatively after autotomy of one, the other, or both normal chelae, effected once only or repeatedly as new chelae appeared at moulting. New chelae are regenerated repeatedly with little or no waning of growth intensity but in continuously growing chelae, growth intensity is substantially reduced at the end of the instar of autotomy. The amount of growth is not correlated with thenumber of days available for regeneration. When both chelae regenerate simultaneously the larger one grows relatively slower than the smaller one to the end of the instar of autotomy but afterwards this condition is reversed. When the nipper alone is autotomised, growth of the crusher is inhibited and shrinkage may occur. Crusher autotomy, on the other hand, stimulates nipper growth and to an extent which varies with the dimension.The problem of chela reversal has been discussed and certain suggestions have been preferred.     

Phytoplankton of a mountain lake (L’adové pleso,the Tatra Mountains,Slovakia): Seasonal development and first indications of a response to decreased acid deposition

A one-year study of the phytoplankton of remote mountain lake L’adové pleso (2057 m. a.s.l.), situated in the High Tatra Mountains, was carried out in 2000–2001. Seasonal development of the species structure and depth distribution of biomass, as well as chlorophyll-a concentrations, and chemical characteristics of the lake water were examined. The phytoplankton was made up of a low number of nanoplanktonic unicellular species, mainly flagellates from Cryptophyceae and Chrysophyceae. Plagioselmis lacustris, Cryptomonas cf. erosa and Ochromonas spp. were the most important with regards to both abundance and biomass. The phytoplankton showed a marked seasonal development. During most of the ice-covered period, abundances of phytoplankton remained very low. In regard to the vertical distribution, both species composition and total biomass were clearly stratified during most sampling dates. The amount of chlorophyll-a per unit biovolume varied considerably, and significantly higher values were found on sampling dates with complete or partial ice cover. Our data on pH and phytoplankton were compared with a previous study in 1990–1991 in order to evaluate possible changes associated with the decrease of acid deposition. The extent of episodic acidification of the lake water has diminished both in time and space, and lake water pH has slightly increased. We observed a shift in species composition, and an important increase of total phytoplankton abundance. This could be considered as a first sign of biological response to changing chemical conditions.     

Recent advances in lactoferrin research and development during the past two years (2007–2009): in lieu of a preface of the special issue lactoferrin

This is a short preface of this Special Issue Lactoferrin, it described the major points of key reporters in ‘The 9th International Conference on LF Structure, Function and Applications’ in Beijing in late Autumn 2009, and the major articles published in this issue. A panaroma and the lastest advances of lactoferrin R&D during past two years (2007–2009) was tried to extract.