Aptychopsid plates - jaw elements or protective operculum

The three plates characteristic of Aptychopsis have been described as a jaw apparatus in this orthocone cephalopod as well as an operculum for it. Due to the limited material, interpretations have in various cases been made from photographic illustrations and those results are discussed in this article. The area of the aptychopsid plates is compared with the apertural area of the cephalopod and the results show a great similarity. Arguments for and against soft parts outside the aptychopsid plates are discussed as well as the position of the plates. Material from a Silurian shale in southern Sweden is described. ? Aptychopsis, aptychopsid plates. Cephalopoda, operculum, jaw apparatus, Silurian.     

A molecular phylogeny of Phasmatodea with emphasis on Necrosciinae,the most species‐rich subfamily of stick insects

The phasmatodeans or stick and leaf insects are considered to be a mesodiverse insect order with more than 3000 species reported mainly from the tropics. The stick insect subfamily Necrosciinae comprises approximately 700 described species in more than 60 genera from the Oriental and Australian region, forming the most species‐rich subfamily traditionally recognized within Phasmatodea. However, the monophyly of this taxon has never been thoroughly tested and the evolutionary relationships among its members are unknown. We analyse three nuclear (18S and 28S rDNA, histone 3) and three mitochondrial (CO II, 12S and 16S rDNA) genes to infer the phylogeny of 60 species of stick insects that represent all recognized families and major subfamilies sensu Günther and the remarkable diversity within Necrosciinae. Maximum parsimony, maximum likelihood and Bayesian techniques largely recover the same substantial clades, albeit with highly discordant relationships between them. Most members of the subfamily Necrosciinae form a clade. However, the genus Neohirasea – currently classified within Lonchodinae – is strongly supported as subordinate to Necrosciinae, whereas Baculofractum, currently classified within Necrosciinae, is strongly supported within Lonchodinae. Accordingly, we formally transfer Neohirasea and allied taxa (namely Neohiraseini) to Necrosciinae sensu nova (s.n.) and Baculofractum to Lonchodinae s.n. We also provide further evidence that Leprocaulinus, until recently recognized as Necrosciinae, belongs to Lonchodinae, and forms the sister taxon of Baculofractum. Furthermore, Lonchodinae is paraphyletic under exclusion of Eurycantha and Neopromachus. We reinstate the traditional view that Neopromachus and related taxa (Neopromachini sensu Günther) are a subgroup of Lonchodinae and transfer those taxa + the New Guinean Eurycanthinae accordingly. Morphological evidence largely corroborates our molecular‐based findings and also reveals that Menexenus fruhstorferi is a member of the genus Neohirasea and is thus transferred from Menexenus (Lonchodinae) to Neohirasea, as Neohirasea fruhstorferi comb.n . (Necrosciinae s.n. ). Other phylogenetic results include Areolatae and Anareolatae each supported as polyphyletic, Heteropteryginae and Lanceocercata (Bayesian analysis) are monophyletic, albeit with low support, and Necrosciinae s.n. and Lonchodinae s.n. are recovered as sister taxa (Bayesian analysis).     

SEED DENSITY, COVER, PREDATION AND THE DISTRIBUTION OF BIRDS IN A BEECH WOOD IN SOUTHERN SWEDEN

The distribution of six species of birds within a beech wood was analysed in two winters when beech seeds were abundant. All species were concentrated in patches where seed density was high in one winter, but only two showed a similar distribution in the second winter. The distribution of the other four species, three tits Parus spp. and the Nuthatch Sitta europaea, was positively correlated with low cover. Cover was inversely correlated with seed density. Bird predators were recorded many times during the second winter but not at all during the first winter. It is suggested that predator avoidance was more important than food density for some species in the second winter. The relationships between bird density and both food and cover were sigmoid in shape. The proportion of the seed crop consumed by the birds was estimated at about 4.5%, which was probably more than the amount consumed by mammals. The Woodpigeon Columba palumbus (which took 44% of the total seeds consumed by birds) and the Brambling Fringilla montifringilla (33%) were the most important seed consumers among the birds.     

Phylogenetic significance of the kinethmoid‐associated Y‐shaped ligament and long intercostal ligaments in the Cypriniformes (Actinopterygii: Ostariophysi)

Liao, T.Y. & Kullander, S.O. (2012). Phylogenetic significance of the kinethmoid‐associated Y‐shaped ligament and long intercostal ligaments in the Cypriniformes (Actinopterygii: Ostariophysi). —Zoologica Scripta, 42, 71–87. The phylogenetic significance of the Y‐shaped and long intercostal ligaments in the Cypriniformes is examined using character optimization in 184 species representing 20 non‐ostariophysan teleost species, five ostariophysan orders, seven cypriniform families and 14 cyprinid subfamilies. Character states were optimized on the phylogenetic trees of previous studies. Given the topology of Saitoh et al. (2011) , the Y‐shaped ligament, connecting the kinethmoid to the ethmoid complex, is shown to be a synapomorphy for the Cyprinidae, with reversals observed in the Cyprininae, Danioninae, Gobioninae and Psilorhynchinae. The condition of the Y‐shaped ligament is consistent within most subfamilies with a few exceptions. Despite the exceptions, the Y‐shaped ligament may be considered as a diagnostic character distinguishing cyprinid subfamilies with otherwise similar morphology, that is, the Danioninae and Opsariichthyinae. The long intercostal ligament, connecting five to eight ribs and ascending from the subdistal end of the fifth rib, is present in the Catostomidae and all cyprinid subfamilies, except for the Psilorhynchinae and two developmentally truncated genera, Danionella and Paedocypris. In addition to these two cypriniforme families, the long intercostal ligament is homoplastically present in some catfishes. Given the topology of Saitoh et al. (2011) , presence of the long intercostal ligament is a synapomorphy of Cyprinidae+Catostomidae. Some shorter ligaments are also present in the Cypriniformes and Chilodus gracilis (Characiformes), near the base of the anterior ribs and only occurring anterodorsally to the putative line of the long intercostal ligament even when it is absent.     

Terminal Motility in Elongating Stolons of Proboscidactyla flavicirrata

Proboscidactyla flavircirrata is a commensal hydroid whose stolonselongate rapidly in the absence of its host. Growth pulsationscomparable to those of other hydroids originate endogenouslyin each stolon tip, although influenced by the to and fro movementsof the hydroplasm. Neither growth pulsations nor elongationappear to depend upon cellular proliferation, because the distalends of stolons lacked mitotic figures and since irradiationsufficient to halt mitosis failed to stop stolon elongation.Cellular migration is also apparently unessential for elongationbecause severed stolon tips, isolated from potential sourcesof reusable cells, nevertheless elongated. Marking experimentssuggested that cells changed shape rather than location as severedtips advanced. In old preparations the stolons became attenuatedbecause the tips continued to progress without adequate recruitmentof cells. Stolons deprived of their tips failed to elongatealthough they were still connected to the remainder of the colonyand contained mitotic cells. Cytochalasin B simultaneously haltedgrowth pulsations and stolon elongation in a reversable manner.Apparently stolon tip locomotion in Proboscidactyla is essentialto the elongation process.     

The Upper Tremadocian (Ordovician) graptolite Bryograptus: taxonomy, biostratigraphy and biogeography

Abstract:  The taxonomy, biostratigraphical and palaeogeographical distribution of the Lower Ordovician graptolite genus Bryograptus is evaluated. Bryograptus is recognized as a distinct triradiate anisograptid with a multiramous, pendent rhabdosome. The species of the genus Bryograptus can be interpreted as shallow water faunal elements with a strongly limited biogeographical distribution to the Atlantic Faunal Realm. Bryograptus is restricted to a narrow interval in the Upper Tremadocian, the Bryograptus Biozone of Scandinavia and South America (Argentina), making it a taxon with a high potential for precise biostratigraphical correlations. The proximal end development can be used to differentiate the genus Bryograptus from other pendent multiramous graptoloid genera with a homoplastic rhabdosome development. Characteristics of the proximal end development and structure easily differentiate these genera in relief specimens, but not in flattened material.     

Parasitoid vibrations as potential releasing stimulus of evasive behaviour in a leafminer

Abstract. The aim of this study was to characterize the vibratory signals produced by the parasitoid Sympiesis sericeicornis Nees (Hymenoptera: Eulophidae) while foraging on apple leaves infested by one of its hosts, the spotted tentiform leafminer Phyllonorycter malella (Ger.) (Lepidoptera: Gracillariidae).This leafminer changes its behaviour as a function of the parasitoid's behaviour to escape parasitization.We propose that the leafminer uses vibrations triggered by the parasitoid to detect the presence of its enemy.We measured vibrations produced by a foraging parasitoid on a mine with a laser vibrometer.By recording concurrently the behaviour of the parasitoid on video, vibrations could be assigned to particular behaviours.Subsequently, vibrations were characterized by their dominant frequencies and intensities.The behaviours Landing and Take-off both produced strong impact-like vibrations characterized by an initial irregular phase during which frequencies up to 25 kHz occurred followed by a slow decaying regular phase.Vibrations elicited by Moving, Standing and Probing showed no clear temporal pattern.During Probing , dominant frequencies of up to 5.6 kHz were observed frequently at intensities well above the background noise (>10 dB).During Moving and Standing , vibrations were more scarce and of lower frequencies and intensities.Due to their impact-like nature, vibrations produced by Landing and Take-off are probably not specific to the parasitoid.Vibrations produced by Moving and Standing are difficult to detect and not reliable because of their non-specificity.Therefore, only Probing provides a reliable and detectable source of information for the host.The vibrations elicited during Probing could account for the evasive behaviour that is observed in this and other leafminers.