Larval Feeding in Echinoderms

In all four types of feeding echinoderm larvae, particles areretained upstream from the ciliated band, probably by an inducedlocal reversal of ciliary beat. Comparative studies and theoreticalconsiderations suggest that increasing the length of the bandmay be the only means of increasing the rate at which wateris processed for paniculate food. This would account for thelong looping band and late development of adult structures inechinoderm larvae. Estimates of the minimum food requirementsof early echinplutei and of uptake of amino acids by embryosare calculated. Various means of rejecting particles are describedand observations related to nervous control of feeding and rejectionare discussed. The possible disadvantages of larvae developingfrom smaller but more numerous eggs are discussed. It is arguedthat loss of a feeding larval stage is usually an irreversibleevolutionary change in echinoderms, and some general implicationsof the irreversibility of such a change in life history arementioned.     

Aestivation among ornithopod dinosaurs of the African Trias

Thulborn, Richard A. 1978 07 15: Aestivation among ornithopod dinosaurs of the African Trias. Lethaia . Vol. 11, pp. 185–198. Oslo. ISSN 0024–1164.
Dental and circumstantial evidence supports the theory that ornithopod dinosaurs of the African Red Beds responded to seasonal changes in their environment by resorting to aestivation (dry season dormancy). One group of ornithopods. the heterodontosaurids. apparently suppressed tooth replacement to permit efficient grinding of their plant food and probably replaced their entire cheek dentitions while aestivating. The sympatric fabrosaurid ornithopods had a simple open-and-shut jaw action and replaced their teeth continuously in standard reptilian fashion. Seasonal dormancy must have imposed major constraints on the lives of fabrosaurids and heterodontosaurids. and these constraints are summarized in the model of a circannual life cycle.     

The inheritance of morphological variation in Pileolaria pseudomilitaris (Polychaeta: Spirorbidae)

The genetic control of morphological variation (expressed as heritability) was examined by means of laboratory culture in Pileolaria pseudomilitaris. Fourteen of 22 traits examined were shown to have an appreciable genetic component, after an analysis of variance among groups of full siblings. The range of variability for several traits is as large within a single sibling group as the difference between described species in the family.
Comparisons among samples of P. pseudomilitaris from two habitats revealed no consistent morphological dillerences. A similar comparison between P. pseudomilitaris and its nearest congener, I', potswaldi , indicated significant differences for 15 of 22 traits, although ranges overlapped for all bin two of these.     

Arenonemertes arenicolus sp.n. (Nemertea) from the Swedish west coast, with notes on the genus Arenonemertes

Arenonemertes arenicolus sp.n. is described from the Gullmar Fjord, Sweden. It differs from A. microps Friedrich, 1933 in: (1) lacking cephalic glands, (2) having an undivided caecum on the midgut, whereas the caecum is divided into three lobes in A. microps , and (3) the position of the nephridial ducts in relation to the lateral nerves (dorsal instead of ventral). Arenonemertes microps is still considered a valid species, but it is poorly described and the type material has been lost.     

Experimentally increased soil temperature causes release of nitrogen at a boreal forest catchment in southern Norway

Boreal forest ecosystems are sensitive to global warming, caused by increasing emissions of CO₂ and other greenhouse gases. Assessment of the biological response to future climate change is based mainly on large-scale models. Whole-ecosystem experiments provide one of the few available tools by which ecosystem response can be measured and with which global models can be evaluated. Boreal ecosystem response to global change may be manifest by alterations in nitrogen (N) dynamics, as N is often the growth limiting nutrient. The CLIMEX (Climate Change Experiment) project entails catchment-scale manipulations of CO₂ (to 560 ppmv) and temperature (by + 3 to + 5 °C) to whole forest ecosystems in southern Norway. Soil temperature is increased at 400-m² EGIL catchment by means of electric cables placed on the soil surface. Soil warming at EGIL catchment caused an increase in nitrate and ammonium concentrations in runoff in the first year of treatment. We hypothesize that higher temperature increased N release by mineralization. Whether these responses are only transient will be shown by additional years' treatment.     

The immature stages of some Phlebotomine sandflies from Brazil (Diptera: Psychodidae)

Immature stages of Lutzomyia anduzei (Rozeboom), L.antunesi (Coutinho), L. flaviscutellata (Mangabeira), Psychodopygus davisi (Root), Ps.paraensis (Costa Lima) and Ps.lainsoni Fraiha & Ward are described from specimens reared in the laboratory. The Lutzomyia species are members of the intermedia group, though L. flaviscutellata larvae more closely resemble those of Psychodopygus species. The larvae of L.anduzei and L. antunesi are separable on minor setal differences and are similar to previously described members of the intermedia group. Ps. paraensis is distinguishable from the other two Psychodopygus species described, by the absence of prothoracic seta 2. Head seta 5 of Ps.davisi is about twice the length of that in Ps. paraensis and larvae of Ps.lainsoni are pale and characterized by colourless body setae 4 and 10. A key to the fourth instar larvae is given which includes all the known larvae of the intermedia group and of the genus Psychodopygus. Morphological differences in the Psychodopygus larvae do not appear to reflect the separation of the adults into series.     

Elevation of Serum Dopamine-β-hydroxylase Activity with Forced Immobilization

THE formation of the neurotransmitter noradrenaline from 3,4-dihydroxyphenylethylamine (dopamine) is catalysed by the enzyme dopamine-β-hydroxylase (DBH)¹. This enzyme is associated both with the catecholamine-containing chromaffin granules in the adrenal medulla^2,3 and with the vesicular structures in sympathetic nerve terminals which contain catecholamines⁴. Furthermore, DBH activity is released with catecholamines into the perfusate after stimulation of either the isolated perfused adrenal gland⁵ or the isolated perfused spleen^6–8. DBH activity has been reported in the serum of both man and the rat^9,10. This activity is similar to adrenal and sympathetic nerve DBH activity with regard to cofactor requirements, oxygen requirement and kinetic characteristics^9,10. It has been suggested that serum DBH activity might be present as a result of release of enzyme with catecholamines from the adrenal glands and sympathetic nerves. If this is the case, serum DBH activity might be a useful and convenient index of sympathetic-adrenal activity. The work described here was undertaken to investigate both the source of the serum DBH and the effect on this activity of forced immobilization, a procedure which has been used as a model of stress and which has been shown to release catecholamines from the adrenal gland and increase catecholamine excretion¹¹.     

A revised ammonite zonation of the Boreal Oxfordian and its application in northeast Greenland

A revised ammonite zonation for use in the Middle–Upper Oxfordian of the Boreal province is put forward. The zonation is used to date late Jurassic sediments in the Wollaston Forland area of northeast Greenland. The sediments broadly comprise basinal mudstones and shallow marine and shoreline sandstones, which were deposited in westerly tilted fault blocks during three transgressive pulses. On the peneplaned surfaces of wide tilted fault blocks a thick sequence of tidally and fluvially influenced marine sandstones of Middle Jurassic age was deposited. In the Upper Jurassic deposition initially took place in the centre of the basin where 80 m of shoreface sandstones accumulated (Jakobsstigen Member). In the second pulse the upthrown margin of the next fault block to the west was transgressed and deposition of basinal mudstones (Bernbjerg Formation) commenced in the basin centre on the main part of the dip-slope of the eastern block. Finally the crestal areas of the block on Kuhn Ø were inundated in Kimmeridgian times, and then subsided rapidly.