Palaeontologic and biogeochemical characterization of the Cyrtograptus lundgreni event in the black shales of eastern Mid-Sardinia, Italy

A succession of biotic and geochemical changes that occurred during the Cyrtograptus lundgreni Event (Late Wenlock) have been recorded from the 'pelagic' black-shales in the Goni section, eastern mid-Sardinia, Italy. The studied interval encompasses the Cyrtograptus rigidus to Pristiograptus dubius-Gothograptus nassa zones. The fossil association includes graptolites, chitinozoans and microplankton i.e. probable linings of agglutinated foraminifera and radiolaria capsular membranes. Analysis of the chitinozoan distribution revealed a succession of several chitinozoan associations with low species diversity and dominated by opportunistic species. Three chitinozoan faunal turnovers and three extinction events have been recorded. Two of them coincide with graptolite extinctions whereas one probably is of local significance. Disappearance of the chitinozoan and microplankton associations occurred during four consecutive graptolite zones. Geochemical data (trace elements analysis) showed significantly higher (up to c. 100%) values for Co and Cd in the sedimentary organic matter (SOM) than in the whole rock samples. Possible relationships between peaks of metal enrichment, the major faunal changes among chitinozoans, extinction events among chitinozoans and graptolites and, to a certain extent, oceanic events may be inferred. The first extinction datum is older that those occurring in Gotland, Sweden and Thüringen, Germany and is so far considered to be of local significance. The second extinction datum of Sardinia can be matched with Datum 1 of Gotland and Thüringen. A close correlation between the third extinction datum of Sardinia and Datum 2 of Thüringen and Gotland reinforces the importance of these events at global scale.     

Distinguishing between the Wenlock graptolite biozonal indicesCyrtograptus centrifugus andCyrtograptus murchisoni

The lower Wenlock biozonal indicesCyrtograptus centrifugus andCyrtograptus murchisoni, although easily separated as entire mature rhabdosomes, by the former’s tighter rhabdosome curvature proximally and the latter’s secondary cladia, are very similar proximally, the position of the sicular apex offering the most satisfactory basis for distinction. InC. centrifugus the apex reaches only to the aperture of th1, whilst inC. murchisoni it reaches to above the top of th1.     

Trilobite size-frequency distributions, recognition of instars, and phyletic size changes

Size-frequency analysis of over 5,000 Ordovician trilobites from the Teretiusculus Shales of the Builth inlier, central Wales, has revealed size distributions with counter intuitive shapes. Not only do most species show normal or slightly skewed distributions, despite the preponderance of moults, but there is no evidence of instar peaks. Such features can, however, be explained by reference to steady-state population structures of Recent marine arthropods, in which small individuals often form only a minor proportion of the post-larval population structure. Trilobite steady-state population structures would have differed in detail from species to species, but certain distribution shapes may have been characteristic of particular environments. These findings necessitate a reappraisal of previous work on trilobite size-frequency distributions, survivorship and recognition of instars. The Builth data also show the first clear evidence of phyletic size increase and parallel size changes in trilobites. ▭ Trilobites, size-frequency distributions, steady-state populations, instars, phyletic size changes.     

A high-precision global biostratigraphy of myodocope ostracods for the Silurian upper Wenlock Series and Ludlow Series

The wide, trans-oceanic geographical distribution of myodocope ostracods during the Silurian (especially during the Ludlow and Pridoli epochs), and their widespread preservation in rocks of that age, permits the establishment of a transcontinental biostratigraphy of comparable resolution to coeval graptolite/chitinozoan/conodont biozones. Seven myodocope biozones, extending from the Homerian Stage, upper Wenlock Series Cyrtograptus lundgreni graptolite biozone to the middle part of the Ludfordian Stage of the Ludlow Series, enable a time-resolution for each biozone of circa 1 million years. These biozones can provide high-resolution correlation across Europe into Arctic Russia and Central Asia. There is also the potential for a myodocope biostratigraphy applicable from the uppermost Silurian (Pridoli) to the Carboniferous.     

Evolutionary and ecological significance of Lepidaster grayi, the earliest multiradiate starfish

Lepidaster grayi Forbes, 1850, from the Much Wenlock Limestone Formation (Silurian: Wenlock) of England, is the earliest species of starfish (Echinodermata: Asteroidea) to deviate from pentaradial symmetry, having 13 rays rather than five. Based on the patterns of supernumerary ray development seen in extant multiradiate asteroids, two possible models are evaluated for the origin of the eight additional rays seen in L. grayi . In the 'all-in-one' model, all rays were added in the same interradius, whereas in the 'quadrants' model generations of rays would have been added in each of four interradii. The smallest specimen of L. grayi , apparently having only nine rays, suggests that the 'quadrants' model is most probable for the species. The presence of supernumerary rays in Silurian starfish, coupled with the existence of numerous other Palaeozoic multiradiate taxa, shows that asteroids have been able to deviate from pentamerism for most of their evolutionary history, and the variety of methods of supernumerary ray addition indicates that the multiradiate condition is homoplastic. The ecological significance of multiradiate Palaeozoic starfish is reviewed: the mouth frame of L. grayi had considerably greater flexibility than that of contemporaneous five-rayed species and, in combination with its supernumerary rays, enabled L. grayi to manipulate and consume larger food items. It is probable that Silurian starfish utilized a similar range of trophic guilds as those exploited by extant taxa.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 150 , 743–754.     

Momordica mossambica sp. nov. (Cucurbitaceae) from miombo woodland in northern Mozambique

Momordica mossambica , a new species of the Cucurbitaceae from miombo woodland in northern Mozambique is described. In spite of being known only from the type collected in 1964, a morphological and molecular survey of all known species of Momordica indicates that M. mossambica is a distinct species. The closest relatives are M. calantha and M. cabrae from Tanzania and central Africa, respectively, from which it is distinguished easily by its 7-lobed, maple-like leaves.     

Silurian acritarchs from the type Wenlock and Ludlow of Shropshire,England

Acritarch taxa are recorded and listed from the Wenlock and Ludlow from the type areas in Shropshire, England, and other localities in the Welsh Basin of South Wales and the Welsh Borderland of England. The ranges of 141 taxa of stratigraphic value are plotted. Five new genera are described: Hogklintia, Lepto brachion, Rhaco brachion, Salopidium and Wrensnestia. 36 new species are described, and 32 new combinations proposed. Seven acritarch zones are recognised in the Wenlock and Ludlow.     

Systematics, shell structure and affinities of the Palaeozoic Problematicum Cornulites

The genus Cornulites, with the type species C. serpularius Schlotheim, 1820, from the Silurian of Gotland, comprises annulated, conical or tubular calcite shells, often found attached to the hard parts of other organisms. No consensus has ever been reached over the zoological affinities of the taxon, and no examples of soft‐part preservation are known: detailed examination of shell structures and growth patterns provide the only means of assessing its systematic position. Using transverse and longitudinal thin sections of C. serpularius Vine, 1882, and C. cellulosus sp. nov. , from the Much Wenlock Limestone Formation of England, the shell structure of Cornulites is shown to be lamellar, but with conspicuous internal chambers (camerae) at the apical end of the shell and, particularly in C. cellulosus, numerous smaller vacuities (cellulae) between the lamellae in the apertural shell region. Growth of the shell was by the secretion of low‐magnesian calcite increments within one another, giving a cone‐in‐cone structure, with the prominent development of cellulae in C. cellulosus probably a constructional feature relating to an upright life position. By comparison of morphology and shell structure with other taxa, the zoological affinities of Cornulites are re‐examined; previously suggested affinities with annelids, foraminifers, molluscs and poriferans can be ruled out. Specific shell structures, most notably pseudopuncta similar to those of bryozoans and brachiopods, have led some recent workers to interpret cornulitids as lophophorates. However, it is shown that they can be interpreted alternatively as solitary, aseptate members of the stem‐Zoantharia (Cnidaria: Anthozoa). Four cornulitid species are recognized in the Much Wenlock Limestone Formation: C. cellulosus sp. nov. , C. gremialis sp. nov. , C. scalariformis and C. serpularius. In the absence of the type material, C. serpularius is here restricted to cornulitids closely resembling the specimens originally figured by Schlotheim. © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150 , 681–699.     

Extinction and opportunistic evolution among late Wenlock graptolites

The late Homerian was a time of profound importance to graptolites. Following the complete extinction of Cyrtograptus and the near extinction of Monograptus (s.s.)at the end of the lundgrenitestis Zone(lower Homerian, upper Wenlock), the morphologically simple and long-ranging Pristiograptus dubius lineage underwent rapid (opportunistic) cladogenesis during the succeeding upper Homerian. Two clades, each with novel and sometimes complex sicular and thecal structures, appeared. One clade, the 'Pristiograptus' praedeubeli group, gave rise to similar but more complex species, such as ' P.' ludensis and 'P.' deubeli , which in turn gave rise to Ludlow taxa, including Saetograptus (s.l.) and Pseudomonclimacis. The other clade, the Lobograptus group, gave rise to Ludlow taxa Lobograptus, Neolobograptus, Bohemograptus , and Neocucullograptus some with very complex thecal structures. Ludlow and younger monograptid faunas therefore comprise at least three separate lineages: Monograptus (s.s.), the Lobograptus group (clade), and the 'Pristiograptus' praedeubeli group (clade). Cladogenesis, evolution, extinction, Homerian, PRISTIOGRAPTUS, LOBOGRAPTUS     

Studies on the Pollen Morphology and Seed Coat of the Genus Cistanche (Orobanchaceae) in China

In the present paper pollen grains of 5 species and seed coat of 4 species of the genus Cistanche (Orobanchaceae) from China were examined by scanning electron microscope As a result, two types of the pollen exine sculpture are distinguished: (1) tuberculate, C. salsa and C. lanzhouensis; (2) rugulate or fine reticulation formed by the fusion of rugae, C. sinensis, C. deserticola and C. tubulosa. Chinese Cistanche was classified into two sections based on the gross morphology by the present author (Zhang, 1984). C. lanzhouensis and C. sinensis were included in one section. This classification is in conflict with the pollen type, which indicates that the characters of pollen grains and external morphology in this genus have evolved at different rates. The differences in pollen morphology of Chinese Cistanche can serve as characters for delimitating species. According to our abservation, C. lanzhouenis Z. Y. Zhang differs from the other members of Cistanche not only in external morphology but also in pollen morphology. Pollen grains are subprolate in this species, while prolate in the other four species, and exine sculpture is tuberculate. The present study provides the establishment of this new species (Zhang, 1984) with palynological evidence. The seed coat sculpture in Chinese Cistanche are constantly alveolate, but there are some slight differences, by which the sculpture can be divided into two types: (1) testa cells have or have not thickenings on the inner anticlinal walls; cavernulous sculpture is present on outer periclinal wall of some cells: C. sinensis; (2) testa cells have striate thickenings on the inner anticlinal walls: C. salsa, C. deserticola and C. tubulosa. The characters of seed coatof some significance for the delimitation of species.     

志留纪笔石Oktavitesexcentricus(Bjerreskov,1975)的古生物学特征及地层意义*

陕西紫阳地区在古地理上位于扬子台地西北缘,区域内志留纪地层发育,其中志留系兰多维列统(Llandovery)特列奇阶(Telychian)笔石相地层出露较为完整,笔石带较为连续。Oktavites excentricus(Bjerreskov,1975)是特列奇阶Oktavites spiralis笔石带重要的伴生分子,在世界范围内广泛分布。文中通过对紫阳地区一系列特列奇阶剖面研究后认为,Oktavites excentricus较短的化石延限和广泛的古地理分布使其具备地层对比潜力,这将为Oktavites spiralis笔石带的进一步细分提供依据。同时,Oktavites excentricus胞管为典型的奥氏笔石式,其笔石体的盘旋方式又与稍晚的Cyrtograptus lapworthi(Tullberg,1883)(笔石带化石,弓笔石类的早期代表)十分接近,因此,对该种的演化过程的研究也为讨论弓笔石的起源过程提供了更多参考。     

An association between the stromatoporoid Diplostroma yavorskyi Nestor and calcareous algae from the Much Wenlock Limestone, England

Intergrowths of the stromatoporoid Diplostroma yavorskyi Nestor with calcareous algae are described for the first time from the Much Wenlock Limestone of Wenlock Edge, England. The intergrowth developed as irregular. nodular growth-forms which initiated around a nucleus of biomicrite sediment or skeletal clasts. The paired stromatoporoid laminae characteristic of this species form regular alternations throughout substantial portions of the skeleton with the calcareous algae Girvanella sp., Rothpletzella sp., Wetheredella sp. and Rhabdoporella sp., and micrite. Nodular growths developed as a result of intermittent rolling on the sea floor. The nature of the periodic intergrowth of different taxa suggests that the stromatoporoid grew on firm substrates by lateral growth at an edge zone. Epiphytes encrusted areas of the stromatoporoid skeleton devoid of soft tissue. □ Stromatoporoid. calcareous algae. epiphyte. intergrowth. Wenlock.     

1070. Corydalis pseudobarbisepala Fedde: Papaveraceae

Corydalis pseudobarbisepala Fedde is described and illustrated. The species is at present known only from two mountains in west central Sichuan Province in the Republic of China, and has not been reported from its type location for 100 years.     

Wenlock carbonate,level bottom,brachiopod-dominated communities from Wales and the Welsh Borderland

Four marine level bottom communities are described from Wenlock carbonate rocks (i.e. the Wenlock and Woolhope limestones) of Wales and the Welsh Borderland. The communities are: (1) Sphaerirhynchia wilsoni, (2) Isorthis clivosa, (3) Eoplectodonta duvalii, and (4) Visbyella trewerna. The Sphaerirhynchia wilsoni community is divided into: (a) an argillaceous micrite phase, and (b) a biomicrite phase. The communities and the phases are defined on the basis of consistent and recurrent numerical species combinations.The community spectrum from Sphaerirhynchia wilsoni to Visbyella trewerna is broadly correlated with an increase in water depth. The communities show no correlation with major limestone facies types. It is suggested that turbulence, rates of sedimentation and substrate type are some of the environmental parameters, in the shallow near-shore regime, which determine the distribution of brachiopods.     

甘肃南部异蝽科昆虫调查及区系初步研究(半翅目:异蝽科)

本文报道了2007～2010年间采自甘肃南部的半翅目异蝽科标本,经鉴定共有3属20种。本次调查所得的种类中,以东亚分布型为最多,约占全部种属的2/3,东洋分布型约占1/4,古北分布型本次调查所得的种类最少,只占1/10左右。说明甘肃南部具有较强的东亚区系特色,反映了此地区地处生物地理学中极具中国固有特色的东亚区系发祥地——中国中部和中西部地区的地理特点。其中有甘肃省新纪录7种,分别是光华异蝽Tessaromerus licenti Yang,亮壮异蝽Urochela distincta Distant,短壮异蝽Urochela falloui Reuter,黑足壮异蝽Urochela rubra Yang,褐壮异蝽Uroechla punctata Hsiaoet Ching,绿娇异蝽Urostylis genevae Maa和匙突娇异蝽Urostylis striicornis Scott。     

Index

The species of Caenonomada, a bee genus characteristic of the xeric habitats of eastern South America, are revised. Three species are recognized, including a new one, C. labrata sp. nov., from central Brazil. A lectotype is designated for C. tertia Cockerell, 1912, which is considered a synonym of C. unicalcarata (Ducke, 1908). This species has its main area of occurrence in the semi-arid Caatinga of northeastern Brazil and two isolated records, here interpreted as disjunct populations, in central Brazil and in Tucumán, Argentina. C. bruneri Ashmead, 1899 occurs in northern Argentina, Paraguay, and southern Brazil. Tetrapedia pluricinctaVachal, 1909, previously considered a species of Caenonomada, is transferred to the genus Monoeca Lepeletier &; Serville, 1828. An identification key and illustrations are provided. Phylogenetic analysis based on morphological characters of adult specimens supported only one hypothesis of relationship among the species: ((C. bruneri + C. labrata sp. nov.) C. unicalcarata). The resulting area cladogram implies two vicariance events, followed by dispersal of C. unicalcarata from northeastern Brazil to the arid regions of northern Argentina. The historical relationship between the areas, as indicated by the present study, is different from that obtained by other authors who studied forest associated organisms. It is postulated that this divergence is due to the fact that the historical hypotheses refer to different ancestral biotas, one associated with xeric habitats and the other associated with forest habitats.     

Geographical distribution of Anopheles minimus species A and C in western Thailand.

Elucidating vector distribution based on an accurate species identification is important to understanding the nature of the species complex in order to achieve vector control. Morphologically, An. minimus s.l. is difficult to distinguish from both its species complex and its closely related species. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and a single multiplex-allele specific PCR developed for species identification were applied in this study in comparison with morphological identification. Both methods were used, combining with geographical information systems to determine the distribution of An. minimus species A and C. The investigation on the breeding habitats was performed in the malarious area of western Thailand. Anopheles larvae were collected from 36 bodies of water among five districts (Sangkhaburi, Thong Pha Phum, Si Sawat, Muang, and Sai Yok) of Kanchanaburi Province, Thailand. In this study, An. minimus A larvae were present in all study districts but the association differed when focusing on study sites within each district. Although there were many reports of An. minimus A in Ban Phu Rat and Ban Phu Toei villages in Sai Yok District, we did not find the breeding sites of species A in those two areas. An. minimus A and C were found in Ban Phu Ong Ka village in Sai Yok District. The breeding habitats of An. minimus C were present covering 30-40 km of distance in northern part of Sai Yok and this species was also found in the central and southern parts of Si Sawat District.     

Alien plants in central Australia

The central Australian flora currently contains 78 alien species, of which 17 are predominantly summer-growing, 19 are southern winter-growing species reaching roadsides, stockyards and watercourses in the southern Northern Territory and 42 are at present confined to gardens in Alice Springs. A further 11 species reach the far north of South Australia or die far southwest of Queensland but not the Northern Territory. The central Australian alien flora may be classified by growing season and drought-tolerance, or broadly categorized on the basis of habitat and dispersal agent into 'garden weeds', 'tourist weeds' and 'stock weeds'. Present ecological knowledge of central Australian aliens is limited, but indicates that whilst some will probably remain confined to better-watered habitats, many are likely to spread into the arid areas, becoming obvious only after a succession of wet years. The central Australian alien flora is increasing at present and this increase is expected to continue.     

大王马先蒿的传粉综合征状及其生物地理学意义

对云南西北部中甸和昆明黑龙潭的大王马先蒿（ＰｅｄｉｃｕｌａｒｉｓｒｅｘＣｌａｒｋｅＣ．Ｂ）的不同居群进行了传粉生物学观察。大王马先蒿花为黄色,花冠短管、无喙、具二齿、无蜜腺,是一种原始的花冠类型。该种由红腹熊蜂（ＢｏｍｂｕｓｆｒｉｓｅａｎｕｓＳｋｏｒｉｋｏｖ）和明亮熊蜂（ＢｏｍｂｕｓｌｕｃｏｒｕｍＬ．）的工蜂在直立的位置上,通过震动花粉背触式传粉;同时也观察到红腹熊蜂的工蜂在倒悬的位置上,通过震动花粉腹触式传粉。熊蜂的工蜂在大王马先蒿上的这两种传粉综合征状的发现,可能是仅存在于马先蒿原始类型中的一种特殊现象。