The Middle Devonian lycopsid Haskinsia Grierson et Banks from the Ruppert Coast, Marie Byrd Land, West Antarctica

New observations on leaves of herbaceous lycopsid specimens previously attributed to Drepanophycus schopfii Mildenhall from Marie Byrd Land, West Antarctica, indicate that they belong to Haskinsia colophylla Grierson et Banks. Haskinsia was a wide spread lycopsid during the Middle Devonian.     

The herbaceous lycophyte Haskinsia Grierson and Banks from the Devonian of western Venezuela, with observations on leaf morphology and fertile specimens

The Devonian herbaceous lycophyte genus Haskinsia Grierson and Banks is characterized by narrow dichotomizing stems and helically arranged petiolate leaves with a broad, approximately deltoid, lamina. New specimens are reported from four horizons in the Lower Member of the Campo Chico Formation, Sierra de Perijá, western Venezuela. H. sagittaka Edwards and Benedetto has sagittate leaves, and fertile specimens are reported for the first time; the ellipsoidal/obovoid adaxially-flattened sporangium is attached to unmodified leaves towards the top of the petiole in the adaxial position. H. sp. has sagittate leaves which are larger than any yet attributed to the genus but is represented by only three specimens. H. hastata sp. nov. has hastate leaves; the sporangia are more globose but positioned similarly to those of H. sagittata. The occurrence of the sporangia on unmodified microphylls indicates that Haskinsia is a member of Protolepidodendrales. The status of Haskinsiaceae is discussed. The Venezuelan specimens are compared with other records of Haskimi and Haskinsia -like plants from North America, Kazakhstan, North China, North Africa and Antarctica.     

Two species of Haskinsia Grierson & Banks (Lycopsida) from the Middle Devonian of Xinjiang,China, and consideration of their palaeogeographical significance

Two species of the Devonian herbaceous lycopsid Haskinsia Grierson & Banks, H. hastata Berry & Edwards and H. sagittata Edwards & Benedetto, are reported from the Hujiersite Formation (Givetian–Middle Devonian), Xinjiang, north‐west China. Both species were first described from Venezuela. Haskinsia hastata from Xinjiang has hastate leaves with toothed margins, and a pair of basal narrow lateral segments which curve distally. It is assigned to a new subspecies because of the toothed margins which cannot be demonstrated in Venezuelan material. The scar of the sporangium stalk is observed for the first time in specimens of H. sagittata, on the leaves of which a possible ligule structure is also shown. On the basis of our observations on both Xinjiang and Venezuelan specimens, the diagnosis of Haskinsia is enlarged to accommodate plants whose lamina has entire or toothed margins. The palaeophytogeography of the genus, otherwise known from South and North America, is discussed. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157 , 633–644.     

THE CUTICLE OF DREPANOPHYCUS SPINAEFORMIS,A LONG-RANGING DEVONIAN LYCOPOD FROM NEW YORK AND EASTERN CANADA

The presence of paracytic stomata and paired guard cells on specimens presumed to be Drepanophycus spinaeformis Göppert from eastern Canada and New York State supports the conclusion of Banks and Grierson that the species is not a reliable index of Lower Devonian strata. The interpretation of stomatal morphology demonstrates that the species lived in Early, Middle, and Late Devonian time and that slender specimens are distinct from zosterophylls such as Sawdonia that had anomocytic stomata and a single guard cell. Knowledge of the stomata also permits a reinterpretation of the stomatal apparatus as first described by Lang. Siegenian specimens of the genus apparently represent the oldest occurrence of paired guard cells and of paracytic stomata.     

LECLERCQIA COMPLEXA: EARLIEST LIGULATE LYCOPOD (MIDDLE DEVONIAN)

Our discovery of a ligule on Leclercqia complexa Banks, Bonamo and Grierson 1972 is the earliest occurrence of a ligulate lycopod in the fossil record. The ligule 1) occurs on a homosporous lycopod, differing with current concepts that the ligule is linked with the heterosporous condition; 2) is located on the leaf far distant from the attachment of leaf to stem, thus differing in position from any known ligulate lycopod, extinct or extant; 3) is comparable in morphology to ligules of extant lycopods, therefore providing no clues as to any earlier specialized function. These findings extend the enigma of the function of the ligule back in time, but necessitate a re-evaluation of the spatial relationship of the leaf and the ligule and of the link between heterospory and the ligule.     

First Record of Eocene Bony Fishes and Crocodyliforms from Canada’s Western Arctic

Background

Discovery of Eocene non-marine vertebrates, including crocodylians, turtles, bony fishes, and mammals in Canada’s High Arctic was a critical paleontological contribution of the last century because it indicated that this region of the Arctic had been mild, temperate, and ice-free during the early – middle Eocene (∼53–50 Ma), despite being well above the Arctic Circle. To date, these discoveries have been restricted to Canada’s easternmost Arctic – Ellesmere and Axel Heiberg Islands (Nunavut). Although temporally correlative strata crop out over 1,000 km west, on Canada’s westernmost Arctic Island – Banks Island, Northwest Territories – they have been interpreted as predominantly marine. We document the first Eocene bony fish and crocodyliform fossils from Banks Island.

Principal Findings

We describe fossils of bony fishes, including lepisosteid (Atractosteus), esocid (pike), and amiid, and a crocodyliform, from lower – middle Eocene strata of the Cyclic Member, Eureka Sound Formation within Aulavik National Park (∼76°N. paleolat.). Palynology suggests the sediments are late early to middle Eocene in age, and likely spanned the Early Eocene Climatic Optimum (EECO).

Conclusions/Significance

These fossils extend the geographic range of Eocene Arctic lepisosteids, esocids, amiids, and crocodyliforms west by approximately 40° of longitude or ∼1100 km. The low diversity bony fish fauna, at least at the family level, is essentially identical on Ellesmere and Banks Islands, suggesting a pan-High Arctic bony fish fauna of relatively basal groups around the margin of the Eocene Arctic Ocean. From a paleoclimatic perspective, presence of a crocodyliform, gar and amiid fishes on northern Banks provides further evidence that mild, year-round temperatures extended across the Canadian Arctic during early – middle Eocene time. Additionally, the Banks Island crocodyliform is consistent with the phylogenetic hypothesis of a Paleogene divergence time between the two extant alligatorid lineages Alligator mississippiensis and A. sinensis, and high-latitude dispersal across Beringia.     

Factors affecting location of Banks grass mite,Oligonychus pratensis (Acari: Tetranychidae), on corn leaves

The site on which adult female Banks grass mite,Oligonychus pratensis (Banks), settled when placed on corn (Zea mays L.) leaves was significantly influenced by light, leaf surface, and gravity. Mites chose the abaxial side of corn leaves when light was excluded as a factor. With a light source present, the mites went to and stayed on the leaf surface away from light. In the absence of light and leaf-surface influences, gravity showed significant effect on the choice of the under site of corn leaves by the mites; this effect also existed with light present, and acted in concert with normal light conditions (i.e., light from above). Results suggest that both heat and ultraviolet light may be responsible for the observed light effect.     

Host Selection by the Herbivorous Mite Polyphagotarsonemus latus (Acari: Tarsonemidae)

This study examined the host-selection ability of the broad mite Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae). To make long-distance-shifts from one host plant patch to another, broad mites largely depend on phoretic association with whiteflies. However, the host plants of whiteflies and broad mites are not necessarily the same. We determined the host-preference and acceptance of free-moving and phoretic broad mites using two behavioral bioassays. We used a choice test to monitor host selection by free-moving mites. In the case of phoretic mites, we compared their rate of detachment from the phoretic vector Bemisia tabaci placed on leaves taken from various host plants. The suitability of the plant was further determined by monitoring mite’s fecundity and its offspring development. We compared the mites’ responses to young and old cucumber (Cucumis sativus cv. ‘Kfir’) leaves (3rd and 8–9th leaf from the apex, respectively), and two tomato (Solanum lycopersicum cvs. ‘M82’ and ‘Moneymaker’). Free-moving mites of all stages and both sexes preferred young cucumber leaves to old cucumber leaves and preferred young cucumber rather than young tomato leaves, demonstrating for the first time that broad mites are able to choose their host actively. As for phoretic mated females, although eventually most of the mites abandoned the phoretic vector, the rate of detachment from the whitefly vector was host dependent and correlated with the mites’ fitness on the particular host. In general, host preference of phoretic female mites resembled that of the free-moving female. Cues used by mites for host selection remain to be explored.     

稻城千里光(菊科-千里光族)的名实订正

通过标本(包括模式标本)检查,发现稻城千里光(Senecio daochengensis Y. L. Chen)与黑褐千里光(S. atrofuscus Grierson)属于同一种植物,故将前者处理为后者的异名。提供了黑褐千里光的地理分布图及其与近缘种的检索表。     

Do components of colonization - dispersal cycles affect the offspring sex ratios of Banks grass mites (Oligonychus pratensis)?

The effects of two host plant species, immature rearing density, and feeding-induced leaf damage on the offspring sex ratios of individual Banks grass mites (BGM) (Oligonychus pratensis Banks) were examined. Offspring sex ratios did not differ among corn-reared females transferred to corn or two sorghum genotypes. Likewise, the offspring sex ratios did not differ among females from three rearing densities. However, female BGM reared on damaged leaves produced significantly more daughters than females reared on undamaged leaves. This suggests that offspring sex ratios of BGM change in response to a deteriorating food source. Greater daughter production on a deteriorating host results in more potential dispersers and colonizers of new host plants. This may be an important adaptation facilitating the colonization-dispersal episodes that characterize the BGM life history.     

Biomass and density of 2 seagrass species in southern Quintana Roo, Mexico

The biomass and productivity of a seagrass community are useful for determining the ecological status of the coast. Leaf biomass and shoot density in beds of Thalassia testudinum Banks & Sol. ex K. D. Koenig, were compared for two environments in the Mexican Caribbean coast (N = 6 quadrants/site) in November 1998. Shoot and leaf biomass values were lower in the mangrove-associated meadow than in the reef lagoon meadow. This could be related to the higher percentage of epiphytes on the leaves. In addition, T. testudinum had more biomass than Syringodium filiforme Kütz in the reef lagoon.     

Instar sizes,life cycles,and food habits of five Rhyacophila (Trichoptera: Rhyacophilidae) species from the Appalachian Mountains of South Carolina,U.S.A.

The larval head widths at each instar, life cycles, and food habits of late instars were determined for five species of Rhyacophila from two Appalachian mountain streams in South Carolina, U.S.A. Rhyacophila acutiloba Morse & Ross was univoltine with two cohorts, one emerging in the spring and another presumably emerging in early autumn. Rhyacophila fuscula (Walker), R. nigrita Banks, and R. carolina Banks were apparently multicohort, univoltine species with extended flight periods. Rhyacophila minor Banks was univoltine with a spring emergence. All species were predaceous and consumed mainly Plecoptera nymphs and Trichoptera larvae.     

Banks grass mite (Oligonychus pratensis) abundance on sorghum cultivars with different levels of nitrogen use and metabolism efficiency

Banks grass mite (Oligonychus pratensis (Banks)), abundance was recorded for three years on sorghum (Sorghum bicolor (L.) Moench) cultivars with different levels of nitrogen (N) use and metabolism efficiency. The cultivars included 77CS1, SC630-11E, R6956, and SC325-12. Nitrogen fertilizer was applied to plots containing each cultivar at 0,45, and 180 kg Na ha^–1. Significantly more mites were on plants at 180 kg N ha^–1 than at 0 or 45 kg N ha^–1. The lowest mite densities were recorded on SC325-12, the N-use-inefficient and N-metabolism-efficient cultivar. In July,O. pratensis abundance was statistically equivalent on SC325-12 and on R6956, the other N-metabolism-efficient cultivar. In August, mite densities on R6956 were as high as on 77CS1 and SC630-11E, which are N-metabolism-ineficient cultivars. Mite densities were lower on N-use-inefficient and N-metabolism-efficient sorghum cultivars than on their respective efficiency counterparts. Physiological differences in N-use and metabolism-inefficient cultivars may influence the amount of leaf N plus the amount and form of amino acids and other N-based chemicals in sorghum leaves. These plant chemicals have been shown to influence mite abundance on several hosts, and may have been key to influencing the results of these experiments.     

Male meiosis in camel-flies (Raphidioptera; Neuropteroidea)

Male meiosis in 3 species of the raphidioptera genus Agulla-- A. bicolor Banks, A. astuta (Banks), and A. bractea Carpenter-- closely parallels that of Neuroptera. The diploid complement in each comprises 12 pairs of autosomes plus X and Y; all are mediokinetic. One male of A. bicolor carried an extra pair of autosomes indistinguishable from the shortest member of the usual set: these formed a normal bivalent and segregated synchronously with the other autosomes. The spindle is formed by the collocation of individual units which envelope each chromosomal mass. The sex chromsomes are spatially separate on emergence from the joint vesicle of early prophase; oriented toward opposite poles they move into this interpolar axis and a central spindle unit forms about them. This unit elongates disproportionately in early premetaphase, and its subsequent contraction is not synchronous with that of the other units. Distance segregation of X and Y is completed in early premetaphase. Autosomal bivalents are chiasmate; their congressional maneuvers involve, in addition to the usual interpolar oscillations, a lateral movement to the periphery of the spindle to form a variably complete ring at the equator. Autosomal univalents occurs with a frequency of 13% in A. bicolor, 2% in A. astuta, and 1% in A. bractea; they undergo distance segregation with the sex chromosomes in the central spindle unit. The phylogenetic significance of the data is considered.     

束长蝽科若虫记述及其系统学意义(半翅目:异翅亚目)

有关束长蝽科若虫期的报道很少,其中束长蝽亚科尤其如此,迄今只有Ｍａｌｃｕｓ ｆｌａｖｉｄｉｐｅｓ Ｓｔａｌ一种曾有详细描述。本文首次记述Ｍａｌｃｕｓ ｓｉｎｉｃｕｓ Ｓｙｔｓ（５龄）,Ｍ．ｅｌｏｎｇａｔｕｓ Ｓｔｙｓ（５龄和４龄）以及Ｃｈａｕｌｉｏｐｓ ｂｉｓｏｎｏｔｕｌａ Ｂａｎｋｓ（５龄）的若虫,并记录寄主植物。对于腺毛系统及其系统学意义进行了讨论。     

Changes in protein quantities of phosphoenolpyruvate carboxylase and Rubisco activase in various wheat genotypes

In early seedlings of wheat genotypes two isoforms of Rubisco activase with molecular weights of 42 and 46 kDa are expressed. Amounts of both isoforms significantly increase in early seedlings of the durum wheat genotype Barakatli-95 exposed to salt stress. But at the beginning of the tillering stage, the changes in quantities of both RCA isoforms are different in durum and bread wheat genotypes subjected to a 3-day drought stress. In the leaves of the early seedlings of the studied wheat genotypes exposed to drought stress quantities of PEPC subunits increase compared to the control but they remain relatively stable in early roots and germinating seeds. However, quantities of its subunits decrease sharply in roots and germinating seeds of early seedlings under the influence of 100 mM NaCl. In flag leaves and ear elements of the Barakatli-95 genotype grown under normal water supply conditions protein quantities of PEPC subunits change differently depending on time. Changes in protein quantities of RCA, PEPC and Rubisco enzymes have been studied comparatively in ear elements and flag leaves after the fourth day of anthesis.     

LEAF DIMORPHISM IN POPULUS TRICHOCARPA

Critchfield , William B. (Pacific SW Forest & Range Expt. Sta., Berkeley, Calif.) Leaf dimorphism in Populus trichocarpa. Amer. Jour. Bot. 47 (8) : 699–711. Illus. 1960.—In Populus trichocarpa and other species of Populus, each tree bears 2 kinds of leaves, referred to here as “early” and “late” leaves. Both leaf types are present on all long shoots. They differ in many features of external morphology, including petiole length, size and occurrence of marginal glands, venation, and stomatal distribution. This type of foliar dimorphism has its origins in a pronounced difference in leaf ontogeny. The early leaves originate in the developing bud and overwinter as embryonic leaves. The first late leaves are also present in the winter bud, but as arrested primordia, and succeeding late leaves are initiated at the tip of the growing shoot and develop uninterruptedly to maturity during the growing season. A similar correlation between leaf form and the circumstances of leaf ontogeny appears to be a common feature of many other instances of heterophylly. The expansion of the pre-formed early leaves is almost completed by late spring, when the first late leaves begin to grow rapidly. The formation of late leaves may then continue until late in the season. The rapid elongation of the stem does not begin until the first late leaves expand. Elongation is restricted to shoots producing late leaves. Consequently, the early leaves are confined to short shoots and the base of long shoots; adventitious shoots and the upper part of long shoots bear only late leaves. Certain other woody plants with long and short shoots also exhibit a restriction of elongation to those shoots on which a second set of leaves is produced.     

Mites associated with soybean crop in Rio Grande do Sul State, Brazil

During the last growing seasons, high infestations of phytophagous mites were observed in the State of Rio Grande do Sul, Brazil, becoming necessary to apply pesticides for their control. The objective of this study was to identify phytophagous and predatory mite species associated with soybean in ten counties of that state, during the 2002/03 and 2003/04 growing seasons, in five soybean cultivars (A 6001 RG, A 7001 RG, A 8000 RG, A 8100 RG, Anta 82), all genetically modified. In samples of soybean leaves four phytophagous mite species (Mononychellus planki (McGregor), Polyphagotarsonemus latus (Banks), Tetranychus desertorum Banks and Tetranychus gigas Pritchard & Baker) and two predatory mite species (Phytoseiulus fragariae Denmark & Schicha and Typhlodromalus aripo De Leon) were found. T. desertorum was found for the first time associated with soybean in the country. Phytoseiulus fragariae and T. aripo are reported for the first time on soybean. The potential of phytoseid mites as biological control agents in soybean crop was discussed. Among the hypotheses to explain the increasing infestation of soybean fields with phytophagous mites area are the progressively larger cultivated area, the dry spells observed in the last few years in the growing season, changes in soybean cropping system that led to increased use of pesticides and utilization of new soybean cultivars with morphological or biochemicals characteristics that favour the development of these mite populations.     

Prey stage preference and functional response of the predatory mite Galendromus flumenis to Oligonychus pratensis

The Banks grass mite, Oligonychus pratensis (Banks) (Acari: Tetranychidae), is a serious pest in dates (Phoenix dactylifera L.) in the New World. Currently O. pratensis is managed using the miticide, Savey, and alternative strategies are necessary to remove pressure from a single control method due to the risk of resistance evolution. For this purpose, studies are underway to develop biological control strategies using the predatory mite, Galendromus flumenis (Chant) (Acari: Phytoseiidae). The current study determined the consumption rate of G. flumenis at constant densities of O. pratensis eggs, larvae, protonymphs and deutonymphs, and defined the functional response of predator females. The predator consumed significantly more eggs than other prey stages, and displayed a type II functional response on all prey stages. The highest attack rate and shortest handling time were obtained for predators feeding on prey larvae and eggs, respectively. The proportions of prey consumed by G. flumenis were higher at lower densities for all stages of Banks grass mite, implying that G. flumenis should be more effective at suppressing Banks grass mite populations at lower densities. Therefore, in an augmentative release program, G. flumenis would need to be released early in the infestation.