Long-term variability of the phytoplankton community in an isolated floodplain lake of the Ivinhema River State Park,Brazil

The phytoplankton community of river–floodplain ecosystems shows significant temporal fluctuations in response to hydrosedimentological regime. The aim of our study was analyze the effect of the hydrosedimentological regime of the Paraná and Ivinhema Rivers on the interannual variation in the composition, biovolume and functional groups of phytoplankton in an isolated floodplain lake (Ventura Lagoon) of the Ivinhema River State Park, located in the Upper Paraná River floodplain (Mato Grosso do Sul State, Brazil). Samples of phytoplankton were taken at the sub-surface of the pelagic zone of the lake from February 2000 to December 2005. A total of 132 taxa were recorded, and the species that represented greater contributions to the phytoplankton biovolume were grouped into five functional groups (FG) (H1, H2, M, MP and Y). The distribution of the FGs were linked to the high and low water periods in Ventura lagoon. Functional groups MP and Y were the highest contributors to the phytoplankton biovolume during the high water periods, whereas FGs H1, H2 and M contributed more during the low water periods. The FGs were also useful for the interannual characterization of Ventura Lagoon by taking the changes caused by climatological factors into account. There was a strong dominance of Cyanobacteria (H2 and M) in 2000 and 2001 (La Niña periods) coincident with low precipitation and low hydrometric levels of the Paraná and Ivinhema Rivers and, consequently, lower water depths of Ventura Lagoon. In 2002, 2003, 2004 and 2005 (El Niño periods), when higher precipitation, higher hydrometric levels, higher discharge of the Paraná and Ivinhema Rivers and an increased depth of Ventura Lagoon were observed, Cyanobacteria (H1, H2 and M) were dominant, followed by Bacillariophyceae (MP) and Cryptophyceae (Y). These results reported here corroborate the utility of using FGs as indicators of interannual and seasonal variability in floodplain lakes.     

Revision ofSemionotus bergeri Agassiz, 1833 (Upper Triassic, Germany), with comments on the taxonomic status ofSemionotus (Actinopterygii, Semionotiformes).

Semionotus bergeri Agassiz, 1833, from the Upper Triassic (Carnian) of southern Germany, the type species ofSemionotus, is here described in detail for the first time, including so far unstudied material in the Naturkunde-Museum Coburg, which allows a fairly complète reconstruction of this fish. The species is diagnosed by the présence of long frontals, about 4 times longer than wide, with antorbital lateral processes, 6–7 posterior infraorbitals, infraorbital at the posteroventral corner of the orbit notably larger than adjacent ones, infraorbitals at the posterior border of the orbit being as deep as long, and the middle élément anteroventrally expanded, dorsal fin base about two times the anal fin base.S. elegans from the Late Triassic-Early Jurassic of the Newark Supergroup in North America, is so far the best know species ofSemionotus and is the only species of this genus that has been included in phylogentic analyses. However, the comparison ofS. bergeri with other proposed speciesof Semionotus, such asS. elegans, and other semionotids casts doubt on the monophyly of this genus as currently understood, since these species exhibit a mosaic distribution of characters.      

Insect ovipositions on aquatic plant leaves <Emphasis Type="Italic">Quereuxia</Emphasis> from the Upper Cretaceous of the Amur region

New form taxa of insect ovipositions on aquatic plant leaves Quereuxia from the Campanian locality of Udurchukan (Amur Region) are described. Endophytic ovipositions Paleoovoidus flabellatus sp. nov. and P. arcuatus sp. nov. do not differ in shape from ovipositions of recent damselflies. Exophytic ovipositions Palaexovoidus ovoideus gen. et sp. nov., P. catenulatus sp. nov., P. multus sp. nov., and P. amplus sp. nov. belong to insects that develop in the water, probably dragonflies of the suborder Anisoptera. A new family Palaexovoididae fam. nov. is erected.     

Muscle architecture of the upper limb in the orangutan

We dissected the left upper limb of a female orangutan and systematically recorded muscle mass, fascicle length, and physiological cross-sectional area (PCSA), in order to quantitatively clarify the unique muscle architecture of the upper limb of the orangutan. Comparisons of the musculature of the dissected orangutan with corresponding published chimpanzee data demonstrated that in the orangutan, the elbow flexors, notably M. brachioradialis, tend to exhibit greater PCSAs. Moreover, the digital II-V flexors in the forearm, such as M. flexor digitorum superficialis and M. flexor digitorum profundus, tend to have smaller PCSA as a result of their relatively longer fascicles. Thus, in the orangutan, the elbow flexors demonstrate a higher potential for force production, whereas the forearm muscles allow a greater range of wrist joint mobility. The differences in the force-generating capacity in the upper limb muscles of the two species might reflect functional specialization of muscle architecture in the upper limb of the orangutan for living in arboreal environments.     

柴达木盆地冷湖地区中-晚始新世化石轮藻LAMPROTHAMNIUM GANCHAIGOUENSIS 组合带及其层序生物地层学意义

柴达木盆地冷湖构造的一些岩屑古生物分析发现,下干柴沟组上段存在一明显的化石轮藻Lamprothamnium ganchaigouensis组合带,而且这一组合带底界与下干柴沟组上段与下段的地质分界相当。在地震时间剖面上,通过井间追层及化石对比,发现这一化石组合带底界均与T4地震标准层相对应,形成了一个地震层序界面(等时界面)。因此,通过生物地层学与地震地层学的综合研究,可建立层序生物地层单元,具有层序生物地层学意义;地震与古生物资料的联合横向对比还可以帮助评估化石层位和标定地震标准层的相对位置,在生产实践中可节约成本,提高地层对比效率。     

Revision of some parasitic wasps (Hymenoptera: Proctotrupoidea sensu lato) from the Florissant locality,United States

The types of the parasitic wasps described in the families Proctotrupidae, Diapriidae, and Scelionidae (Hymenoptera) from the Upper Eocene Florissant locality (Colorado, United States) are revised. All the specimens are shown to belong to the family Proctotrupidae, representing the genera Oxyserphus, Mischoserphus, Nothoserphus, and Palaeoteleia. The known species are redescribed and two new species, Mischoserphus bruesi sp. nov. and Nothoserphus rasnitsyni sp. nov., are described. A new combination, Oxyserphus exhumatus (Brues, 1910), comb. nov., and a new synonymy, Paramesius defectus Brues, 1910, syn. nov. = Oxyserphus exhumatus (Brues, 1910), are established.     

The Upper Cretaceous belemnite <Emphasis Type="Italic">Praeactinocamax plenus</Emphasis> (Blainville, 1827) from Lower Saxony (Upper Cenomanian,northwest Germany) and its distribution pattern in Europe

Occurrences of the Upper Cenomanian (Upper Cretaceous) belemnite Praeactinocamax plenus from the plenus Bed of northwest Germany (Söhlde-Loges working quarry near Salzgitter, Lower Saxony) are documented and described for the first time on the basis of two in situ finds. The find horizon and its surrounding beds are re-evaluated in a sequence stratigraphical context. In contrast to the interpretations of other authors, the plenus Bed is seen as a pelagization event in a parasequence of transgressively stacked beds, delimited by two significant erosion surfaces below and above. The exclusive occurrence of P. plenus in the top part of the plenus Bed and its absence from the post-plenus Bed succession, in the equivalent of which (higher part of the Plenus Marls Member) it is very common in southern England (Anglo-Paris Basin), is explained by ecological factors in stratigraphically complete sections (intra-shelf depressions) and by gaps in the stratigraphic records in swell settings. The distribution pattern of P. plenus suggests a preference for nearshore settings and a demersal mode of life.     

New Frasnian conodonts of the genus Palmatolepis from the Central Tajikistan

New Lower-Middle Frasnian conodonts of the genus Palmatolepis Ulrich et Bassler, 1926 are described from the Kalagach and Kulyali formations of the Sishkat key section of Central Tajikistan. Palmatolepis manzuri sp. nov. descends from Pa. punctata (Hinde) and is an ancestor of Pa. kireevae Ovnatanova, Pa. salibaevi sp. nov., and also of the Pa. rhenana Bischoff branch.     

Taxonomy, biostratigraphy and paleoecology of Cenomanian and Turonian ostracodes from the Western Interior Basin, Southwest Utah, USA

Cenomanian-Turonian ostracodes are reported from the western Colorado Plateau (Western Interior Basin) in the United States. Fifteen genera and twenty species are illustrated, six of which are new: Cytheromorphaperornata nov. sp., Looneyellaleckiei nov. sp., Asciocythereposterangulata nov. sp., Asciocytherearizonensis nov. sp., Cytheropteronclavifragilis nov. sp. and Hourcqiadakotaensis nov. sp. Three ostracode interval zones are proposed that broadly correspond to the existing late Cenomanian through to Middle Turonian Ammonite-zones of Kauffman et al. (1993). Paleoenvironments range from estuarine to coastal plain.