Chemical defenses against diatom fouling in Antarctic marine sponges

Antarctic sponges are commonly fouled by diatoms, sometimes so heavily as to occlude pores employed in filter feeding and respiration. This fouling becomes heavier during the annual summer microalgal bloom. Polar and non‐polar extracts of eight species of marine sponges from McMurdo Sound, Antarctica were assayed for cytotoxicity against sympatric fouling diatoms. To identify compounds potentially released by sponges as defenses against diatom biofouling, only fractions of crude extracts that were soluble in seawater or 2% methanol in seawater were assayed. Significant bioactivity was present in seven of the eight species. Both Mycale acerata and Homaxinella balfourensis displayed moderate levels of defense against diatoms even though they are not or are only weakly chemically defended against bacteria and predators. Calyx acuarius extracts, which do have antipredator and antibacterial effects, had no effect on diatoms except at levels many fold higher than present in the intact animal. These results strongly suggest some level of specificity for chemical defenses against diatom fouling in antarctic sponges.     

Primo contributo alla conoscenza dei laghi appenninici meridionali di alta quota. Il fitoplancton dei laghi del massiccio del Monte Sirino (Appennino Lucano)

Abstract

A preliminary account on some mountain lakes of the Southern Apennines. Phytoplankton investigation on three ponds of the Monte Sirino (Basilicata).—Phytoplankton standing crop and species composition have been studied in three ponds of the Southern Apennines. The observations carried out throughout ten months in 1975, showed a great number of species present in the Remmo pond, mainly diatoms, desmids, green algae, and blue-green algae. In the Sirino pond only diatoms and Chrysophyceae were present.

In comparison, in the Zapano pond, the phytoplankton was scarcely represented but the occurrence of some species of green algae may suggest a eutrophic water condition. On the basis of the peculiarities both of species composition and biomass, the major water bodies may be considered oligotrophic.     

Spore morphology and some other features of Goniomitrium Hook. & Wils. (Funariaceae)

Abstract

Goniomitrium enerve, G. acuminatum and G. africanum are distinguished mainly on costal features. There are some problems with the Australian species because of intergradation of characters but no name changes have been suggested and a key to species is provided. The spores of the three species, which are monolete and have a large reticulate ornamentation, are distinctive amongst moss spores and appear to be diagnostic for the genus.     

Le diatomee bentoniche del porto di Palermo

Abstract

Benthic diatoms in the harbour of Palermo (Sicily).—The first results of a systematic investigation on the benthic diatoms on the fouling settlements, at four selected sites in the harbour of Palermo, are reported. Samples of comparable areas have been examined either on the fouling of vertical walls of the wharfs or on asbestos panels vertically submerged at the same place for at least eighteen months. Seventy-seven species have been found. No marked taxonomic difference is evident between the populations on the stoneworks and those on the panels.     

Morphology of male and female terminalia and taxonomic revision of the burrower bugs genus Canthophorus (Heteroptera: Cydnidae)

The Palaearctic burrower bug genus Canthophorus Mulsant & Rey, 1866 (Heteroptera: Cydnidae) is revised. New data on the morphology and distribution are given. Structures of the female internal ectodermal terminalia and the completely inflated aedeagi in all species of the genus are described and illustrated for the first time. An extended differential diagnosis as a comparison with representatives of all Palearctic genera of the tribe Sehirini is given for the genus. Based on characters of the external morphology and terminalia of both sexes, new taxa are described: C. dubius sanigarum n. ssp., C. melanopterus mariae n. ssp., C. impressus hajastanicus n. ssp., and C. wagneri hyrcanicus n. ssp.; C. hissaricus Asanova, 1964 is downgraded to a subspecies level and included in C. mixtus Asanova, 1964. C. melanopterus niger (Vidal, 1950) is placed in synonymy with C. melanopterus melanopterus (Herrich-Schaeffer, 1835). A wide variability of the terminalia, especially in females, was found in C. melanopterus melanopterus; in the latter, six forms are described differing in the shape and size of sclerites in posterior pouches of the gynatrial sac and distributed mainly in the Mediterranean region. A key allowing identification of the species not only by males, but also by females, was compiled for the first time. It is shown that C. aeneus (Walker, 1867) [= Sehirus fuscipennis Horváth, 1899] and C. maculipes (Mulsant & Rey, 1852) have very significant differences from other species of Canthophorus in the male and female terminalia, and at the same time share some characters with the genus Adomerus Mulsant & Rey, 1866, including unique characters shared with several species of this group; therefore, the mentioned two species are transferred to the genus Adomerus.     

Systematics of naviculoid diatoms (Bacillariophyta): A preliminary analysis of protoplast and frustule characters for family and order level classification

The relationships between 49 naviculoid diatoms, currently arranged in 14 families and four orders were investigated using cladistic analysis in order to test the types of characters used in diatom systematics and to assess how well the current classification reflects possible phylogenetic relationships in this group. Some of the families and orders comprise taxa with different protoplast characters, or taxa with similar protoplast arrangements are placed in separate families or orders. Therefore as both cell wall and protoplast characters were used, three analyses were undertaken; total data, protoplast data and frustule data. The analyses support the recognition of the Mastogloiales (unequivocally) and the Cymbellales (largely) but indicate that some of the familial groupings are more ambiguous. The members of the Berkeleyaceae, Berkeleya, Parlibellus and Climaconeis, were never grouped together and Achnanthes brevipes never grouped with the other monoraphid diatoms, but usually with members of the Mastogloiales (total and protoplast data). Similarly, Round et al.’s familial groupings within the Cymbellales do not emerge from our analyses. Our results support the hypothesis that monoraphid genera have arisen independently from different naviculoid diatoms, and that Achnanthes sensu stricto should be transferred to the Mastogloiales. Some of the problems associated with incomplete information and inaccurate terminology are discussed briefly.     

Notes on British Boleti: IV

Summary

A key to the British species of the genus Suillus based on habitat, microscopic and macroscopic characters is discussed. Some species as yet unrecorded for the British Isles are included for completeness. Also included in the key are the only W. European member of Fuscoboletinus, the single British species of Bolentis, and two Xerocomus spp., X. badius and X. rubinus, both of which are superficially similar (in some characters) to members of the genus Suillus. The genera Chalciporus and Fuscoboletinus are reviewed and the taxonomic status of Boletus grevillei is discussed in detail.     

Notes on British Boleti: II.

Summary

A key to the species of the genus Boletus sensu stricto based on habitat, microscopic and macroscopic characters is proposed. Three extra-limital species, as yet unrecorded from the British Isles, B. torosus, B. lupinus Krombh. and B. lupinus s. Bres., are included in the key in the hope that they may appear in future. They may have been overlooked previously or confused with far commoner forms, especially B. luridus, to which many quite distinct species have previously been referred. Also included in the key are three boletes not considered taxonomically to belong to this genus in its strict sense, although in some ways they are superficially similar. The only West European species of Tylopilus is keyed out and its taxonomic position considered. Boletus rubellus Krombh. placed by some American authors in Boletus sensu stricto is also discussed.     

Marine tube-dwelling diatoms and their occurrence in the Netherlands

Attached to solid substrate species of the tube-forming diatoms are found th entire Dutch coast. Probably because of the increased eutrophication over the last decades there is an indication that the abundance of certain tube-dwelling species such aParlibellus delognei andParlibellus berkeleya shows also a strong increase. At some favourable sites it is estimated that at there peak of their seasonal development more than 10¹⁰ diatomcells per square metre can be found. The taxonomy of the tube-dwelling species has a long history started in 1803 when the first species were described by the wellknown phycologist Dillwyn. In short this taxonomic history is described. In addition the process of formation and development of the muco-polysaccharide tubes is documented and illustrated. In conclusion the occurance of endo and epitubular symbionts or associates is overviewed. Especially diatoms of the generaNitzschia are found inside the tubes of some species while species from the generaLicmophora, Synedra, Amphora andCocconeis have a preference to become attached to the outer surface of tubes.     

Taxonomic value of seed characters in the Erica tetralix L. group (Ericaceae)

A study of the seed morphology of Erica tetralix and the related species E. mackaiana and E. andevalensis was performed to evaluate the taxonomic importance of seed characters. Size and shape of seeds and surface cells were studied, and area, perimeter, main axis lengths, elongation and sinuosity were measured. Levels of intraspecific variation were considered by means of nested analysis of variance. The study of the intraspecific variation of the characters shows significant differences for lower levels, higher than variations between species for most characters. Levels of variation must be based upon the numerical analysis of seed characters for a correct approach to determining systematic value. E. mackaiana and E. andevalensis group together versus E. tetralix for sinuosity of testa cells. This is a good taxonomic character because it shows significant differences between species and no significant differences between populations. E. tetralix has strongly undulated testa cells while E. mackaiana and E. andevalensis have slightly undulated or curved testa cells. These two species can be discriminated by size of the seed, with seeds of 0.37-0.38 mm for E. andevalensis and 0.4 - 0.45 mm for E. mackaiana. Similarities are found in seed morphology for E. mackaiana and E. andevalensis, but we nevertheless consider the species status for the three taxa as the most natural taxonomic assignment. A key to the species is provided.     

A phylogenetic evaluation of Leandra (Miconieae, Melastomataceae): a polyphyletic genus where the seeds tell the story, not the petals

Melastomataceae is a tropical family of 4500–5000 species divided into nine tribes. The largest tribe, Miconieae, is composed of approximately 2200 species in 30 genera and is found exclusively in the Neotropics. Previous phylogenetic analyses of the Miconieae have suggested that many of the genera are derived from a paraphyletic Miconia. However, these analyses only included six species of the large genus Leandra, so its phylogenetic affinities remained unclear. As currently defined Leandra is characterized by acute petals and terminal inflorescences, but some species of Miconia, Clidemia and Ossaea also have these characters. In this study, we present an analysis of nrITS sequence data for a sample of 63 species of Leandra. The genus is clearly resolved as polyphyletic, but some distinct and well‐supported clades exist. Some of these partially correspond to sections recognized in the nineteenth century by Cogniaux, or to geographic distribution. The distribution of seed structure characters is better correlated with the phylogeny than traditional characters, such as petal morphology. Seed appendages in Leandra have evolved independently at least four times. © The Willi Hennig Society 2007.     

Butterflies of the South Pacific

ABSTRACT

Larvae of the invasive mosquito Culex quinquefasciatus Say are morphologically similar to those of the native Culex pervigilans Bergroth, yet distinguishing these species can be hampered by morphological variations in Cx. quinquefasciatus. We present detail about the extent of these variations in an urban population of Cx. quinquefasciatus in Auckland. To aid in identification of this exotic species, we provide images of key diagnostic characters and some observed exceptions to these. Details regarding variation in diagnostic characters for < 3rd instar and 3rd/4th instar larvae are given. Of the nine characters used for identification, three were highly consistent (dorsal papillae, mantle plate, pecten teeth); each observed in > 90% of larvae, although these characters were not always visible. Other characters were less reliable, for instance, the expected position of seta 1a-S in relation to the pecten teeth was observed in < 10% of larvae. Further exploration of regional morphological variation in both Cx. quinquefasciatus and Cx. pervigilans is recommended, ideally with associated molecular characterisation.     

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.     

Competition between the Cyanobacterium Limnothrix redekei and Some Spring Species of Diatoms under P-Limitation

The nutrient saturated growth and the competition between Limnothrix redekei and some spring diatoms for phosphate were studied in semi-continuous cultures at 10°C with a 6/18 h light/dark cycle and at 15 °C with a 12/12 light/dark cycle. Under these conditions in unialgal cultures, the maximum specific growth rate of Limnothrix redekei was two to three time lower than that of the diatoms. However, Limnothrix redekei was the superior competitor for phosphate under both conditions in mixed cultures. The diatoms in mixed cultures from each species with Limnothrix redekei were competitively displaced but at a different rate. This allowed the diatoms to be ranked in terms of their competitive ability for phosphate at 10°C as follows: Synedra acus > Asterionella formosa > Stephanodiscus minutulus > Nitzschia acicularis > Cyclotella meneghiniana > Stephanodiscus neoastrea > Stephanodiscus hantzschii. The competitive ability of Limnothrix redekei at 15 °C was increased and the rank order of diatoms slightly changed. The hypothesis that cyanobacteria are promoted by phosphate because they are inferior competitors for phosphate is incorrect for Limnothrix redekei.     

Pselaphotumulus,a new genus of pselaphine endemic to New Zealand (Coleoptera: Staphylinidae: Pselaphinae: Pselaphitae)

ABSTRACT

Pselaphotumulus Owens and Carlton, gen. nov., is described as the sixth genus in the tribe Pselaphini known from New Zealand. Three new species are described: Pselaphotumulus aorerei, sp. nov., Pselaphotumulus dubius, sp. nov. and Pselaphotumulus unus, sp. nov.. Three species, Pselaphus cavelli (Broun 1893), Pselaphus oviceps (Broun 1917) and Pselaphus urquharti (Broun 1917) are transferred to Pselaphotumulus, nov. combs. Lectotypes from type series in the New Zealand Broun Collection (Natural History Museum, London) are designated for these three species. Habitus photographs, distributional maps and line drawings of diagnostic characters are provided for each species. A key to species is provided. Searches of museum collections have not yielded representatives outside of New Zealand, suggesting that this is the first endemic genus in the tribe Pselaphini described from the New Zealand’s main islands, specifically, the South Island. Pselaphotumulus species exhibit restricted distribution patterns that approximately coincide with the Pacific/Indo Australian Plate boundary.     

Some osteological differences between the blennioid fishes Limnichthys polyactis and L. rendahli,with comments on other species of Creediidae

Abstract

The two endemic species of New Zealand Limnichthys differ in several osteological characters. L. polyactis differs from L. rendahli in having a rayed dorsal margin of the opercle (cf. entire), little or no gap between the lower limb of the coracoid and the pelvis (cf. wide gap), one epural (cf. two), and narrow posterior neural and haemal spines (cf. wide spines). Comments are given on some characters in the other 10 recognised named species of Creediidae. Squamicreedia obtusa is removed from the Creediidae, and is provisionally placed in the Percophididae.     

Biology of epiphytic Chironomidae (Diptera:Nematocera) in chalk streams

Submerged macrophytes are a conspicuous feature of chalk stream ecosystems, supporting large populations of diatoms and invertebrates, including larvae of the nematocerous family Chironomidae. Close temporal and spatial association is evident between chironomid larvae and diatoms, and diatoms are frequently a major component of the food of midge larvae. Larvae provided with food that is rich in diatoms survive better and grow and develop more quickly than larvae that are supplied with food that is predominantly fine organic detritus. First instar larvae selectively feed on diatoms but it is likely that selection is on the basis of particle size, rather than for diatoms per se. Three species of epiphytic larvae (2 Cricotopus spp. and Eukiefferiella ilkleyensis) transfer to a diet that is predominantly of fresh plant material (Ranunculus calcareus leaves) in the third and fourth instar. The life cycle strategies of many species of Orthocladiinae equip them to exploit temporarily favourable environmental conditions very rapidly and effectively. This fact helps to explain the coexistence of species with similar strategies of resource utilization, as part of the normal epiphytic fauna of chalk streams.     

Ciclo annuale del fitoplancton nelle acque costiere del Parco Naturale della Maremma II. Flora e variazioni delle comunità

Abstract

Annual cycle of phytoplankton in the coastal waters of the « Parco Naturale della Maremma ». II. Flora and communities variations.—The hydrology of the marine coastal area of the Parco Naturale della Maremma and the annual cycle of phytoplankton standing crop have been examined in a preceding paper (Lenzi Grillini e Lazzara, 1978). In the present paper the species list and the main features of marine phytoplankton communities of the same area are reported as a result of an annual cycle of monthly collections effected in seven stations. The most conspicuous seasonal bloomings are due to Skeletonema costatum (Grev.) Cleve in February and to some species of the Chaetoceros gen. in November; the dinoflagellates play a minor role throughout the year, except for Gonyaulax minima Matz. with a light blooming episode in summer. The annual cycle of bottom living diatoms found in the samples appears to be very similar in its shape to the cycle of the pelagic species, as for the standing crop and for the species number. The community structure variations have been analyzed by means of diversity and dominance indexes and of species frequency diagrams. As it concerns the differences in species composition among the seven stations, the area in front of the rocky shore, with deeper and more saline waters, appears to be very homogeneous, whereas some differences have been observed in the shallow waters, in front of the sandy shore and under the influence of the Ombrone River mouth.     

Fifteen important questions in the spatial ecology of diatoms

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