Significance of Middle Cambrian mixed carbonate-siliciclastic units for global correlation: southern Nevada, USA

Sequence-stratigraphic analysis of the Middle Cambrian Highland Peak, Bonanza King, Swasey, and Wheeler formations in the Great Basin refines platform-to-basin correlations and distinguishes local tectonic events from eustasy. This analysis provides a reliable sea-level history through the Ptychagnostus gibbus and Ptychagnostus atavus trilobite intervals and confirms that the Global Stratotype Section and Point (GSSP) at the first appearance datum (FAD) of P. atavus was deposited during an overall sea-level rise. Deposition during the Middle Cambrian Ehmaniella/Bolaspidella biozones in the western U.S. is represented by two lithologically distinct successions: (1) a poorly fossiliferous, shallow-water, mixed carbonate-siliciclastic succession that is widespread across southern Nevada and southeastern California and (2) a highly fossiliferous, deeper water, fine-grained, siliciclastic succession in central Nevada and western Utah. The deeper water succession was deposited within the fault-controlled House Range Embayment and contains the P. atavus GSSP. Correlation of these disparate successions had been hampered by a lack of high-resolution biostratigraphic data, and limited chemostratigraphy and sequence stratigraphy. In this study, sequence-stratigraphic analysis indicates that the Condor Member of the Highland Peak Formation and the “mixed unit” of the Bonanza King Formation are the shallow-water platform equivalents of the basal Wheeler Formation encompassing the P. gibbus and lower P. atavus zones. The deepening event that is recorded in the P. gibbus Zone represents a major flooding surface that may be used as an important event marker for regional and global correlation. The overlying P. atavus GSSP, however, is within the later stage of transgression and may represent a globally synchronous event that can be correlated from platform to basin.     

The first specimen of the Middle Triassic Phalarodon atavus (Ichthyosauria: Mixosauridae) from South China,showing postcranial anatomy and peri‐Tethyan distribution

Phalarodon atavus from the Germanic Muschelkalk Basin was previously represented only by cranial elements. Here we report a nearly complete and articulated specimen of P. atavus from the Middle Triassic Luoping Biota, Yunnan, South China. This is the first specimen of P. atavus from outside the Germanic Basin. This discovery demonstrates a peri‐Tethyan distribution of P. atavus. The new specimen is also the first one preserving the postcranial anatomy of this species, providing the opportunity to evaluate its sustained swimming ability. Inferences made on its functional morphology suggest that this species was probably adapted for active foraging. Tooth crown morphology suggests that P. atavus may have preferred externally soft prey.     

Potential Global Standard Stratotype-section and Point (GSSP) for a Cambrian stage boundary defined by the first appearance of the trilobite Ptychagnostus atavus, Drum Mountains, Utah, USA

The base of the Ptychagnostus (or Acidusus) atavus Zone is one of the most clearly recognizable horizons on an intercontinental scale in the Cambrian System, and would serve as an excellent position for the base of a new stage-level chronostratigraphic subdivision. Among well-exposed, readily accessible sections in Laurentia, the “Stratotype Ridge” section, Drum Mountains, western Utah, USA, is perhaps the most suitable for a Global Standard Stratotype-section and Point (GSSP) defined by the first appearance datum (FAD) of the cosmopolitan agnostoid trilobite P. atavus. In the “Stratotype Ridge” section, the FAD of P. atavus occurs near the base of a calcisiltite bed 62 m above the base of the Wheeler Formation. A position corresponding closely to this horizon can be recognized with precision in Gondwana, Siberia, Kazakhstan, and Baltica using a combination of stratigraphic tools, the most useful of which are trilobite biostratigraphy, conodont biostratigraphy, and sequence stratigraphy. Brachiopod biostratigraphy and chemostratigraphy provide general constraints on the position of the horizon intercontinentally.     

Extended phylogeny of the Craspedida (Choanomonada)

Currently choanoflagellates are classified into two distinct orders: loricate Acanthoecida and non-loricate Craspedida. The morphologically based taxonomy of the order Craspedida is in need of a revision due to its controversial, paraphyletic and inconsistent systematics and nomenclature. In this study, we add molecular data (SSU and parts of the LSU rDNA) of six new Craspedida species isolated from saline, brackish and freshwater habitats to the existing knowledge. Four of these six organisms could be described as new species: Paramonosiga thecata, “Salpingoeca” euryoecia, “Salpingoeca” ventriosa, “Sphaeroeca” leprechaunica, whereas two are assigned to previous morphologically described species: “Salpingoeca” fusiformis Saville Kent, 1880 and “Salpingoeca” longipes Saville Kent, 1880. Paramonosiga is established as a new genus of the Craspedida based on its phylogenetic position. Extending the dataset by six additional sequences shows that the craspedid taxonomy is still unsolved as the type specimen Salpingoeca gracilis has not yet been sequenced and hence a clear assignment to the genus Salpingoeca is not possible. Trying to assign morphological and ecological data to phylogenetic clades is not successful. We give an improved/emended morphological diagnosis for the two redescribed species and add molecular data for all six species, shedding light on their phylogenetic position.     

Taxonomic revision ofMauryna bellardi andChedevillia begiati (strombid gastropods) from the middle eocene of NE Italy

The taxonomy ofMauryna bellardi (Gregorio 1880) andChedevillia begiati (Gregorio 1880) is revised on the basis of new material. Previously unknown morphological characters are described and illustrated. This is the first record ofMauryna (sensu Jung 1974) in the western hemisphere.     

Three new species of Epicephala Meyrick (Lepidoptera,Gracillariidae) associated with Phyllanthus microcarpus (Benth.) (Phyllanthaceae)

Three new species of Epicephala Meyrick, 1880 are described based on specimens reared from fruits of Phyllanthus microcarpus (Benth.): Epicephala microcarpa sp. n. and Epicephala laeviclada sp. n. from Guangxi and Hainan, and Epicephala tertiaria sp. n. from Guangdong and Guangxi. Photographs of adults and illustrations of genital structures are provided.     

The Genera of the Subfamily Heteroderinae (Nematoda: Tylenchoidea) with a Description of Two New Genera

The family Heteroderidae, its two subfamilies Heteroderinae and Meloidogyninae and the nominal genera of Heteroderinae (Heterodera Schmidt, 1871; Meloidodera Chitwood, Hannon &Esser, 1956; and Cryphodera Colbran, 1966) are rediagnosed. Meloidoderita Pogosyan, 1966 is considered a genus inquirenda. Two new genera from southern California are described in the subfamily Heteroderinae. A key to the genera, illustrations and a phylogeny of the Heteroderinae are proposed.     

On the Identity of the Genus Crassolabium (Dorylaimida: Qudsianematidae)

The identity and taxonomy of the genus Crassolabium are discussed based on examination of material of C. australe, its type species and its comparison with Iberian species of close genera. The existence of refractive masses (thickenings) at the inner core of lateral lips, the most distinctive diagnostic feature of Crassolabium, is considered to be of minor taxonomical significance because of its interspecific and even intraspecific variability. It is concluded that Crassolabium and Thonus are identical, and a reversal of precedence among both genera is suggested. Crassolabium australe is re-described, and some comments are provided on C. robustum, the second species in the genus.     

Evolution of C isotopes in the Cambrian of China: implications for Cambrian subdivision and trilobite mass extinctions

Carbon and oxygen isotopes were studied in fossiliferous Cambrian carbonates in northwestern Hunan Province (South China) and in northern Anhui and southern Shandong provinces (North China). Two major C isotope excursions related to biological events occur in the Wangcun section (Yongshun County, northwestern Hunan), which consists of a slope carbonate sequence (510 m thick) containing abundant trilobites. The first C isotope excursion (δ¹³C value shifts from -2.3‰ to 2‰) occurs near the boundary between the Qingxudong and Aoxi formations, close to the traditional Lower-Middle Cambrian boundary. The second excursion (δ¹³C value shifts from 0‰ to 3‰) occurs in the interval between the Linguagnostus reconditus Zone and the Glyptagnostus reticulatus Zone. The base of the G. reticulatus Zone define the base of the Paibi Stage and Furongian Series. Similar C isotope excursions also occur in shallow - water carbonate sections in North China. In Jiagou section near Huainan (Anhui Province), recently considered an important interval for defining the lower-middle Cambrian boundary because of dramatic changes in the trilobite fauna (extinction of redlichiids and appearances of ptychopariids), a negative C isotope excursion (δ¹³C value shifts from +1.21‰ to -1.93‰) occurs at the top of the lower member of the Mantou Formation. In the Gushan section (Changqing County, Shandong Province), a C isotope excursion (δ¹³C value shifts from -0.04‰ to 2.23‰) occurs at the base of the Changshan Formation and is coincident with the base of the Chuangia Zone. This excursion can be correlated with the excursion in the lower part of Glyptagnostus reticulatus Zone in the Wangcun section. The above two distinct C isotope excursions, which occur both in slope carbonates in South China and in shallow - water carbonates in North China, have also been recognized in Cambrian sections on other continents, and they coincide with global mass extinctions of trilobites. The two excursions evidently reflect global changes of Cambrian sea level, and they have utility for Cambrian subdivisions and for both regional and global stratigraphic correlation. In addition, a negative carbon excursion below the base of the Ptychagnostus atavus Zone in the Wangcun section supports previous suggestions that the FAD of P. atavus can be considered as a global correlatable horizon within the middle Cambrian.     

An exceptional Pleistocene specimen of Panochthus Burmeister (Xenarthra, Glyptodontoidea) from Bolivia: Its contribution to the understanding of the Early-Middle Pleistocene Panochthini

Knowledge of the Early-Middle Pleistocene (Ensenadan Age/Stage ; ca. 1.8-0.4 Ma) South American Glyptodontidae (Cingulata) is still poor compared with the Late Pleistocene-Early Holocene taxa (Lujanian Age/Stage). This is especially true for the Glyptodontidae Panochthini, in which it is possible to recognize two Ensenadan species from the Pampean region of Argentina, Panochthus intermedius and P. subintermedius, known only by their type material. Prior to this contribution, the knowledge of P. intermedius, a taxon with biostratigraphic importance for being considered as a guide taxon of the Ensenadan Age/Stage of South America, was limited to a dorsal carapace. The finding of an exceptional almost complete specimen from the Early-Middle Pleistocene of Bolivia has allowed us to greatly improve the morphological characterization of this species, and discuss some taxonomic aspects related to the other Ensenadan Panochthini. This specimen represents the most completely known Panochthini and one of the most complete Glyptodontidae from the Early-Middle Pleistocene of South America.     

Revision of the Australasian genus Pseudidarnes Girault, 1927 (Hymenoptera,Agaonidae, Sycophaginae)

The species of Pseudidarnes are revised, and six species are described: P. acaudus Farache & Rasplus, sp. n.; P. astridae Farache & Rasplus, sp. n.; P. badiogeminus Farache & Rasplus, sp. n.; P. cooki Farache & Rasplus, sp. n.; P. kjellbergi Farache & Rasplus, sp. n.; P. laevis Farache & Rasplus, sp. n. Pseudidarnes minerva Girault, 1927 and P. flavicollis Bouček, 1988 are redescribed. A key to the species is provided as well as illustrations for all females and all known males (except the wingless male of P. minerva). We also provided further discussion on ecology, morphological patterns, and host taxonomy. Online dichotomous and multi-access interactive LUCID keys to all Pseudidarnes species are available at http://www.figweb.org/.     

Paragonimus and Paragonimiasis in Vietnam: an Update

Paragonimiasis is a food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. In Vietnam, research on Paragonimus and paragonimiasis has been conducted in northern and central regions of the country. Using a combination of morphological and molecular methods, 7 Paragonimus species, namely P. heterotremus, P. westermani, P. skrjabini, P. vietnamensis, P. proliferus, P. bangkokenis and P. harinasutai, have been identified in Vietnam. Of these, the first 3, P. heterotremus, P. westermani and P. skrjabini, are known to infect humans in other countries. However, in Vietnam, only P. heterotremus, found in some northern provinces, has been shown to infect humans. Even nowadays, local people in some northern provinces, such as Lai Chau and Yen Bai, are still suffering from P. heterotremus infection. In some provinces of central Vietnam, the prevalence and infection intensity of P. westermani metacercariae in freshwater crabs (the second intermediate hosts) are extremely high, but human cases have not been reported. Likewise, although P. skrjabini was found in Thanh Hoa Province, its pathogenicity to humans in Vietnam still remains uncertain. The results of molecular phylogenetic analyses of Vietnamese Paragonimus species provides new insights on the phylogeny and taxonomy of the genus Paragonimus. Comprehensive molecular epidemiological and geobiological studies on the genus in Vietnam and adjacent countries are needed to clarify the biodiversity and public health significance of the lung flukes.     

Highly hydroxylated steroids of the starfish Archaster typicus from the Vietnamese waters

Five new steroidal compounds, including an unusual glucoside, along with several known steroids were isolated from the starfish Archaster typicus collected in shallow waters of Quang Ninh province (Vietnam). Three new compounds are 27-nor-cholestane derivatives and the other two are 24,26-dihydroxycholestane derivatives. A biogenesis pathway for the unusual side chain of 27-nor-cholestane derivatives is proposed. Isolated compounds presented moderate toxic effects in the sperm- and 8-blastomere tests on embryonal development of the sea urchin Strongylocentrotusintermedius.     

Identification of Staphylococcus intermedius Group by MALDI-TOF MS

The Staphylococcus intermedius Group includes S. intermedius, S. pseudintermedius and S. delphini, coagulase-positive bacteria commonly isolated from animals. The identification of organisms belonging to this group is presently carried out using molecular methods. This study assessed the suitability of MALDI-TOF MS for their identification. 69 strains of different biological and geographic origins, identified by partial hsp60 gene sequencing as S. intermedius (n = 15), S. pseudintermedius (n = 32) and S. delphini (n = 22), were analyzed by MALDI-TOF MS. The estimated sensitivity, specificity and efficiency were calculated. In addition we computed the agreement between the outcome of MALDI-TOF MS identification and partial hsp60 gene sequencing. The sensitivity of MALDI-TOF MS was higher for S. intermedius [0.95 (95% CI: 0.68-0.99)], than for S. pseudintermedius [0.78 (95% CI: 0.60-0.90)] and S. delphini [0.64 (95% CI: 0.41-0.83)], whereas the specificity was 1 for S. intermedius and S. delphini and 0.97 (95% CI: 0.86-0.99) for S. pseudintermedius. The Cohen's kappa coefficient indicated almost perfect agreement between MALDI-TOF MS and hsp60 gene sequencing for the identification of S. intermedius [0.96 (95% CI: 0.87-1.04)], and substantial agreement for S. delphini and S. pseudintermedius [0.70 (95% CI: 0.52-0.89) and 0.76 (95% CI: 0.616-0.92), respectively]. The overall efficiency of the proteomic identification ranged between 0.88 (95% CI: 0.78-0.95) for S. pseudintermedius and S. delphini and 0.99 (95% CI: 0.92-0.99) for S. intermedius. MALDI-TOF MS is thus a valuable and reliable tool for the rapid and accurate identification of bacteria belonging to the S. intermedius Group.