Building the Coleoptera tree‐of‐life for >8000 species: composition of public DNA data and fit with Linnaean classification

The species representation of public databases is growing rapidly and permits increasingly detailed phylogenetic inferences. We present a supermatrix based on all gene sequences of Coleoptera available in Genbank for two nuclear (18S and 28S rRNA) and two mitochondrial (rrnL and cox1) genes. After filtering for unique species names and the addition of ?2000 unpublished sequences for cox1 and 18S rRNA, the resulting data matrix included 8441 species‐level terminals and 6600 aligned nucleotide positions. The concatenated matrix represents the equivalent of 2.17% of the 390 000 described species of Coleoptera and includes 152 beetle families. The remaining 29 families constitute small lineages with ?250 known species in total. Taxonomic coverage remains low for several major lineages, including Buprestidae (0.16% of described species), Staphylinidae (1.03%), Tenebrionidae (0.90%) and Cerambycidae (0.58%). The current taxon sampling was strongly biased towards the Northern Hemisphere. Phylogenetic trees obtained from the supermatrix were in very good agreement with the Linnaean classification, in particular at the family level, but lower for the subfamily and lowest for the genus level. The topology supports the basal split of Derodontidae and Scirtoidea from the remaining Polyphaga, and the broad paraphyly of Cucujoidea. The data extraction pipeline and detailed tree provide a framework for placement of any new sequences, including environmental samples, into a DNA‐based classification system of Coleoptera.     

Geographical variation in resistance of the parasitoid Asobara tabids against encapsulation by Drosophila melanoqaster larvae: the mechanism explored

Abstract. The braconid parasitoid Asobara tabida Nees attacks larvae of several Drosophila species in fermenting substrates. Northwestern and central European populations of the parasitoid attack mainly D.subobscura Collin. Southern European parasitoids attack mainly D.melanogaster Meigen. Larvae of this last species can defend themselves against parasitoids by encapsulating the parasitoid egg. Parasitoids from southern European populations are better able to resist encapsulation of their eggs than their northwestern and central European conspecifics. The eggs of southern European parasitoids appear to have a 'sticky' egg chorion. As a result of this 'stickiness' the eggs become embedded in host tissue where they are not completely covered by the host's blood cells. This leads to, at most, partial encapsulation of the egg. Parasitoid larvae can escape from partially closed capsules.     

Chondrichthyan‐like scales from the Middle Ordovician of Australia

Abstract: Microvertebrate sampling of the Stairway Sandstone (Darriwilian, Middle Ordovician, central Australia) has yielded scales that are chondrichthyan‐like in their overall construction, and Tantalepis gatehousei gen. et sp. nov. is erected here to describe these specimens. Tantalepis gatehousei gen. et sp. nov. is the stratigraphically oldest microsquamous taxon described thus far, and the ‘shark‐like’ appearance of the scales may extend the chondrichthyan lineage back into the Middle Ordovician. The presence of ‘shark‐like’ scales in the fossil record some 50 myr prior to the first articulated chondrichthyan body fossils and 44 myr before the first clearly identifiable chondrichthyan teeth suggests there is a considerable scope for the recovery of articulated specimens with which to document the early history of crown gnathostomes. Traditional hypotheses of phylogenetic relationships among early jawed vertebrates were recently challenged by the proposal of a radically different tree topology. However, the development of a new data set specifically addressing scale‐based characters is required before taxa such as Tantalepis, that are based upon disarticulated remains alone, can be firmly placed within the emerging, revised, evolutionary narrative.     

A new species of Callinera (Nemertea, Anopla, Palaeonemertea) from the Isle of Man

Callinera monensis sp. n., from Derbyhaven Harbour in the Islc of Man, is described and illustrated. The anatomy of the species is compared and contrasted with that of the other known members of the genus, Callinera buergeri Bcrgcndal and C. buergeri f. grandis Bergendal, from Scandinavian waters; f. grandis is afforded separate specific status as C. grandis Bcrgcndal.     

Expression of Oat-phyA-cDNA in a Suspension Cell Culture of Transgenic Tobacco: A Single-Cell System for the Study of Phytochrome Function

A culture of callus cells has been developed from a transgenicline of tobacco which contains an introduced phyA-cDNA encodingphytochrome A. Suspension cultures of the cells were shown toaccumulate a significant immunodetectable level of the heterologousphytochrome, but not of the native phyA-gene product. The red-irradiatedform (P_fr) of the heterologous phytochrome was specificallydegraded in vivo, and the red-irradiated (P_fr) and far-red-irradiated(P_r) forms demonstrated different patterns of in vitro proteolyticcleavage. These results strongly suggested that the phytochromeapoprotein was associated with a chromophore moiety which mediatedred/far-red sensitive conformational changes of the molecule.Exogenous application of 4-amino-5-hexynoic acid (AHA) to thetransgenic suspension cultures resulted in the accumulationof a population of phytochrome which was stable under red lightand gave identical patterns of in vitro digestion in the redand far-red irradiated forms, i.e. the spectral activity ofphytochrome was inhibited. Application of exogenous 5-aminolevulinicacid (ALA) or biliverdin overcame the inhibitory effects ofAHA to restore spectral sensitivity of the phytochrome pool.These results are consistent with the proposed pathway of phytochromechromophore biosynthesis in intact plant systems. Thus, thetransgenic suspension cultures provided a single-cell systemin which spectrally-active phytochrome, apparently indistinguishablefrom the native phytochrome synthesized in etiolated seedlings,was accumulated. Photoregulation of expression of the genesencoding the small subunit of ribulose-1,5-bisphosphate carboxylaseand chlorophyll a/b binding proteins demonstrated that the heterologousphytochrome population mediated rapid changes in gene expressionin the de-differentiated cells. It is therefore proposed thatsuch a suspension culture of transgenic cells offers a modelsystem for the study of phytochrome function. Key words: Cell cultures, transgenic tobacco, phytochrome, oat-phy A-cDNA, gene expression     

Mitosis in the Rhizopod Lesquereusia spiralis

SYNOPSIS. The interphase nucleus of Lesquereusia spiralis , a testate rhizopod, 20–25 μ in diameter, contains 40–50 endosomes and a diffuse granular reticulum. Onset of nuclear division is marked by a cessation of pseudopod activity. Prophase changes include increase in size of the nucleus, disappearance of the endosomes except the peripheral ones, formation of 175–200 chromosomes from the reticulum, and the appearance of spindle fibers. By the end of prophase a well formed equatorial plate is present. The metaphase nucleus is slightly smaller and elongated; the chromosomes remain distinct. In anaphase the nucleus continues to elongate along the polar axis; the chromosomes apparently split lengthwise and polar caps appear. The nucleus elongates further so that by telophase it has become hour-glass shaped. The spindle fibers are now twisted. Separation of the nuclei takes place in the neck region. The nuclear membrane is unbroken during the process and peripheral endosomes are present at all stages. Total time for mitosis averages 45 minutes.