New Observations on the Choreotrich Ciliate Strombidinopsis acuminata Fauré-Fremiet 1924, and Comparison with Strombidinopsis jeokjo Jeong et al., 2004

ABSTRACT. A choreotrich ciliate collected in waters off Geoje Island, on the eastern coast of the South Sea of the southern coastal water of Korea was morphologically and biometrically investigated through observations of permanent preparations after protargol impregnations. Morphological data and ciliary patterns indicated that the ciliate should be identified as Strombidinopsis acuminata based on the number of somatic kineties. The vertical distribution of the population abundance was also examined in relation to environmental conditions: higher abundances occurred in surface water with higher temperature (22–23 °C), lower salinity (32 psu), and higher concentration (ca 10 μg/L) of chlorophyll a . The 18S rRNA gene of specimens from clonal cultures isolated from natural assemblages was sequenced. While this isolate of S. acuminata is closer to Strombidinopsis jeokjo (99.6–99.8%) than other isolates of S. acuminata (<99.0%), monophyly of S. acuminata was not rejected by the AU test. We discuss the discordance between morphological and molecular data for Strombidinopsis . In order to confirm the species level of the Strombidinopsis specimens, additional information is required based on genealogical analyses of multiple loci.     

Sites of Synthesis and Transport Pathways of Insect Hydrocarbons: Cuticle and Ovary as Target Tissues

SYNOPSIS. The outer surface of insects is covered with a lipidlayer that provides water-proofing and protection against environmentalstresses. Hydrocarbons (HC) are major constituents of this epicuticularwax and they also serve as semiochemicals. In some insects HCare also exploited as biosynthetic precursors for pheromones.HC are synthesized by oenocyteswhich are situated in the integumentor hemocoel. Shuttling of HC to the epicuticie, fat body, andgonads requires transport through an aqueous medium. Insects,unlike vertebrates, use a versatile lipoprotein to effect lipidtransport and to selectively deliver lipids to specific tissues.A high-density hemolymph lipoprotein (lipophorin [Lp]) servesthis function.In adult females of the German cockroach (Blattellagermanica), Lp carries both HC and a contact sex pheromone.Lipophorin is a multi-functional lipid carrier serving alsoas a juvenile hormone binding protein in many insects. Studiesofthe interactions between Lp and HC are beginning to unravelthe routes used in delivering HC to target tissues. We discussthepathways and dynamics of loading of Lp with HC and HC-derivedpheromones, their transport through the hemolymph, and depositionin various tissues, including the epicuticie, ovaries, and pheromone-emittingglands.     

A NEW METRIORHYNCHID CROCODILIAN (MESOEUCROCODYLIA: THALATTOSUCHIA) FROM THE KIMMERIDGIAN (UPPER JURASSIC) OF WILTSHIRE,UK

Abstract: Recent revision of the marine metriorhynchid crocodilians indicates that a partial skull previously assigned to the species Metriorhynchus superciliosus and newly discovered postcranial elements from the Kimmeridge Clay of Westbury, Wiltshire belong to a new species of metriorhynchid. This material is herein described and referred to a new species of the genus Dakosaurus, characterised by four apomorphies: the size and shape of the enlarged supratemporal fossae; relatively large teeth, and half the number in relatives; the robust and unornamented cranium; and the angle that the prefrontal makes with the long axis of the skull. In a new phylogenetic analysis, Dakosaurus carpenteri sp. nov. is the basal member of a clade containing also D. maximus and D. andiniensis: it is not so short‐snouted and its teeth are not so few and large as in the other two species, but the new form illustrates the ecological transition among metriorhynchids from a piscivorous diet to high‐order carnivory.     

Heterochronic evolution in the Heliolites interstinctus-decipiens lineage of the Chaleur Bay region, eastern Canada

A study of the Heliolites interstinctus-decipiens lineage from the Silurian of the Chalcur Bay region, eastern Canada, indicates that most morphological characters of this lineage, including tabularium diameter, coenenchymal tubule diameter and corallite spacing, remain relatively invariate through a Llandovery to Pridoli interval of about 20 million years. In contrast, septal development and corallite wall erenulation show pronounced evolutionary changes due to heterochrony, as shown by comparison of astogenies throughout the lineage. The reduction of septa and the replacement of crenulate corallites by smooth ones in the 'decipiens' type descendent appear to have been by paedomorphosis from the 'interstinctus' type ancestor. The problems of speciation in this lineage are discussed including the alternative hypotheses of a speciation event in the early Ludlow or a phyletic trend within a single species whose longevity is due in part to the stabilization processes of niche separation.     

Effects of temperature and elevated CO2 on cell division in shoot meristems: differential responses of two natural populations of Dactylis glomerata L.

The aim was to establish whether temperature and/or elevated [CO₂] (-700 μmol mol^?1) affects the cell doubling time (cdt) in the different zones of the shoot apex of two natural populations of Dactylis glomerata originating in Portugal (38° S3′ N) and in Sweden (63° 09′ N). In the Portuguese population at ambient [CO₂], only the pith rib meristem (PRM) exhibited a significant shortening of cdts from 10 to 30 °C. Elevated [CO₂] resulted in a significant shortening of cdt, particularly in the PRM where cdt was reduced 4-8- and 6-1-fold at 10 and 20 °C, respectively, but only 2-fold at 30 °C. In the Swedish population at ambient [CO₂], there were no consistent temperature-dependent alterations to cdt and this population was less responsive to elevated [CO₂] than the Portuguese population. Nevertheless, elevated [CO₂] resulted in a significant shortening of the cdt for some of the zones; the maximum reduction occurred in the PRM at 30 °C. We concluded that in the shoot apex of the Portuguese population, and most notably in the PRM, 10 and 20 °C were non-optimal temperatures for cell division, whilst the Swedish population was relatively buffered against temperature change. Elevated [CO₂] resulted in substantially greater reductions in cdts in the shoot meristem of the Portuguese population than in that of the Swedish population.