The oldest labechiid stromatoporoids from intraskeletal crypts in lithistid sponge–Calathium reefs

Early Ordovician (early Floian) reefs of South China include lithistid sponge–Calathium reefs with a three‐dimensional skeletal framework. These structures are among the first post‐Cambrian skeletal‐dominated reef structures and provides an opportunity to test how the novel metazoan builders changed the environments and increased topographic complexity within benthic communities. We document the oldest labechiid stromatoporoid (Cystostroma) in a lithistid sponge–Calathium reef of the Hunghuayuan Formation in southeastern Guizhou, South China. These earliest stromatoporoids may have originated in reefs, and we argue that the complex topography created by the hypercalcified sponge Calathium facilitated the emergence of stromatoporoids. Beyond Cystostroma, keratose sponges, Pulchrilamina (hypercalcified sponge) and bryozoans have also inhabited in the micro‐habitats (cavities and hard substrates) provided by Calathium. These findings suggest that ecosystem engineering by Calathium played an important role in the further diversification of reefs during the Ordovician.     

The limited value of traditional morphometric features in stromatoporoid taxonomy

The morphological variation of stromatoporoids, which are solitary organisms, is partitioned into its presumably genetic and environmental components. Potentially heritable, environmentally mediated and residual components of morphological variability were estimated in a test set containing Devonian stromatoporoids of the genus Gerronostromaria from southern Poland using analysis of variance. The taxonomic importance of traditional morphometric features is limited, because they are dominated by the intra‐skeletal component of variance. Conventional metrics were therefore replaced by stereological and textural quantities. Both stereological and textural features are dominated by the inter‐skeletal and inter‐locality components of variation and thus may be valuable in taxonomic and environmental studies of stromatoporoids. Statistical analyses of these characters (principal component analysis and cluster analysis) were performed. Of 13 characters considered most useful in taxonomic studies, only five have been used previously in conventional species definitions.     

CLASSIFICATION AND CONTROLS OF INTERNAL BANDING IN PALAEOZOIC STROMATOPOROIDS AND COLONIAL CORALS

Abstract:  Palaeozoic corals and stromatoporoids exhibit a variety of internal banding phenomena, many of which have been commonly interpreted as annual growth bands. We evaluate bands through analysis of colonial corals and stromatoporoids from three stratigraphic intervals: Upper Ordovician of Manitoba Canada, and Llandovery–Wenlock and Ludlow of Gotland, Sweden. Banding features are divided into four categories: (1) absence of banding; (2) density banding formed by variation in density or form of elements; (3) growth-interruption banding indicating growth cessation and regeneration; and (4) post-mortem banding caused by compaction or diagenesis. For discrimination of band types, it is essential to examine internal structures and skeletal margins in thin sections or acetate peels. Species vary considerably in degree and type of banding; each has a distinct pattern of variation. We propose criteria to determine if banding is consistent with seasonally induced growth variation: (1) consistency in band character and thickness; (2) continuity of skeletal growth; (3) marginal features; and (4) evidence of diagenetic alteration. Density bands in tabulate and rugose corals probably represent annual growth variations, but results for stromatoporoids are more ambiguous; although stromatoporoids commonly show banding, unequivocal density banding is poorly developed and growth interruption generated most stromatoporoid banding. Cerioid rugose and tabulate corals possess the thickest density bands; the thinnest bands are in stromatoporoids and heliolitid tabulates.     

Growth dynamics in relation to the production of the main cellular components in the toxic dinoflagellate Ostreopsis cf. ovata

In the last decade Ostreopsis cf. ovata blooms have been among the most intense along the entire Mediterranean coast, leading to ecological and human health problems, that are associated with the toxins (palytoxin-like compounds) produced by these algal cells. These compounds are secondary metabolites, whose rates of synthesis depend on the metabolism of their precursors. In general, growth dynamics and toxicity of dinoflagellates reflect the physiological status of the organism. The aim of the present study was to investigate the cellular production of the main biochemical compounds likely involved in the growth and toxicity dynamics of O. cf. ovata during exponential to the late stationary phase in batch cultures of an Adriatic strain. Removal of major nutrients from the medium was monitored along with concentration, biovolume and production of the main cellular components (e.g. polysaccharides, proteins, lipids and toxins). Nutrient uptake, as well as toxin production rates were calculated in the different growth periods. Nutrients (N and P) were completely depleted when cells entered stationary phase and the greatest net toxin production rate (R_TOX) occurred during the first days of growth. The various palytoxins reported a relative abundance quite stable during the different growth phases, while the total toxin cellular amount increased along the growth curve. Total and extracellular released polysaccharides, as well as the lipid content increased greatly during the stationary phase, while proteins were mainly produced by cells during the exponential phase. The continuous release of polysaccharides could facilitate cell aggregation and the formation of the benthic community during algal blooms. The trend of production of the main cellular compounds in O. cf. ovata and the growth dynamics of this species lead us to hypothesize that the fast growth of this dinoflagellate, associated with the rapid use of environmental resources (nutrients, and phosphates in particular), may be an ecological/adaptive strategy which could favor this organism in competition with other species.     

The stromatoporoid animal revisited: Building the skeleton

Modern coralline sponges secrete a skeleton by means of a basal pinacoderm, intracellularly, or inside the soft tissue on an organic matrix The examination of terminal growth surfaces of stromatoporoids indicates that soft tissue in laminate and amalgamate forms occupied the upper galleries and that the skeletal elements were secreted within the soft tissue on an organic matrix. The stromatoporellids and clathrodictyids secreted the skeleton in modules that are homologous to the chambers of a sphinctozoan. In stromatoporellids the module was bounded by a floor that formed the upper layer of the tripatite lamina below and a roof that became the lower layer of the next lamina; it further included the intervening pillars. In clathrodictyids the module had only a roof and pillars, and the laminae are single layers. other stromatoporoids may have secreted their skeletons at the base of the soft tissue and had minimal occupation of the skeleton. *** Stromatoporoid, sphinctozoa, sclerospongiae, sponge, paleobiology.     

New materials of Chalicotherium brevirostris (Perissodactyla,Chalicotheriidae) from the Tunggur Formation,Inner Mongolia

Chalicotherium brevirostris was named by Colbert based on a skull lacking mandibles from the late Middle Miocene Tunggur Formation, Tunggur, Inner Mongolia, China. Here we describe new mandibular materials collected from the same area. In contrast to previous expectations, the new mandibular materials show a long snout, long diastema, a three lower incisors and a canine. C. brevirostris shows some sexual dimorphism and intraspecific variation in morphologic characters. The new materials differ from previously described C. cf. brevirostris from Cixian County (Hebei Province) and the Tsaidam Basin, which may represent a different, new species close to C. brevirostris. The diagnosis of C. brevirostris is revised.     

Cyclocrinitids from the Lower Palaeozoic Tethyan sequence of Spiti,India

Well preserved cyclocrinitids (calcareous green algae) are reported from early Palaeozoic deposits of Spiti, Himachal Pradesh, India. Casts of the algal fossils are preserved in calcareous grey siltstone unit of the Takche Formation (Late Ordovician–Early Silurian) which appears rusty/earthy brown due to weathering. The assemblage includes Cyclocrinites favus, Cyclocrinites pyriformis, Cyclocrinites cf. welleri, Cyclocrinites sp. and Cyclocrinites globosus. Both Cyclocrinites cf. welleri and Cyclocrinites globosus are reported for the first time from the entire Tethyan Himalaya, India. The described algal flora basically denotes relatively shallow marine depositional setting and low to moderate hydrodynamic conditions.     

Study of insectivorous mammals in North Vietnam

An inventory of the insectivorous mammal fauna of the Sa Pa area of Hoan Lien Son National Park (Lao Cai Province, North Vietnam) was conducted in 2005–2006. The high diversity of soricomorphs was found in primary and secondary forest habitats at altitudes from 1900 to 2200 m asl. The recorded species of insectivorous mammals are Neotetracus sinensis, Euroscaptor longirostris, Anourosorex squamipes, Blarinella griselda, C. cf. wuchinensis, C. cf. indochinensis, and Episoriculus leucops.     

Paleoecologic,temporal, and spatial analysis of early Silurian Reefs of the Chicotte Formation,Anticosti Island,Quebec, Canada

Summary Reefs of the Lower Silurian Chicotte Formation are the largest and most faunally diverse known on Anticosti Island, Quebec. They reach up to 25 m in thickness and 250 m in diameter and are present predominantly at two intervals, forming a lower and upper reef cluster. Remnants of bioherms are represented on the present-day wave-cut terrace as 60 to 100 m diameter, subcircular erosional depressions known as Philip structures or as outcrop. The bioherms were relatively low structures, with approximately 3 to 5 m maximum synoptic relief, some of which developed on hardgrounds and possible paleokarst surfaces of crinoidal wackestone and packstone. Dominant skeletal framework builders and sediment producers within all of the reefs are laminar to low domical stromatoporoids, colonial cerioid and fasciculate rugose corals, colonial tabulate corals, and cryptostome bryozoans. Vertical zonation of reef biota is evident within well-exposed reefs of the lower reef cluster. Three to four stages are recognizable:1) a low-diversity tabulate coral-dominatedpioneering community including large tabulate coral colonies (halysitids and favositids), and few stromatoporoids (clathrodictyids, ecclimadictyids), fasciculate rugosans, large generally monotypic stalked crinoids, and shelly benthos (brachiopods, few ostracodes and trilobites);2) an intermediate- to high-diversity, mixed tabulate coral-stromatoporoid-dominatedreef-core community;3) a slightly lower diversity stromatoporoid-tabulate coral-dominatedclimax community with laminar coenitids and alveolitids; and,4) in a few localities, a capping, low-diversity tabulatecoral-dominated (alveolitid and coenitid), and stromatoporoid-bearing community comprising laminar forms. Amelioration of Early Silurian climates, following Late Ordovician glaciation, allowed gradual reestablishment of extensive shallow-water reef growth, by mainly new and increasingly diverse genera and species of metazoans. Reef development within the Chicotte Formation coincided with global, widespread development of latest Llandovery and earliest Wenlock reefs in subtropical to tropical areas. Chicotte reefs have broad characteristics, in terms of overall biotic composition, vertical successions recognized, and paleogeographic setting, similar to those of equivalent and slightly younger age from intracratonic settings in Baltica (Gotland, Sweden and Estonia) and central and northern Laurentia (Midcontinent, U.S.A.; Hudson Bay, Canada; and North Greenland, Denmark).     

Species delineation in the Capitella species complex (Annelida: Capitellidae): geographic and genetic variation in the northern Gulf of Mexico

Capitella capitata was traditionally used as a biological indicator species due to its ubiquitous distribution and high densities in disturbed and polluted marine and estuarine sediments. Based on allozyme and developmental studies, it is now clear that C. capitata is a species complex consisting of multiple distinct lineages worldwide, including the recently described C. teleta, a model species for spiralian development. The coast of the northern Gulf of Mexico, with its numerous bays and estuaries and frequently occurring natural and anthropogenic disturbances, provides an appropriate region for such studies. We sequenced a fragment of the mitochondrial cytochrome c oxidase subunit I gene for individuals of C. cf. capitata and C. cf. aciculata (distinguished by acicular spines on the first two chaetigers) collected from Texas and Florida coasts and analyzed them in conjunction with data available in GenBank. Our results indicate the presence of a Gulf of Mexico clade that is distinct from populations in Canada and the Indo‐Pacific. Populations in the northern Gulf of Mexico are structured geographically, with support for Texas and Florida clades, and there do not seem to be clear boundaries between C. cf. capitata and C. cf. aciculata. This is corroborated by the fact that multiple specimens were morphologically intermediate between the two species. In future studies, we aim to clarify whether the intermediate morphologies represent ontogenetic stages, neutral morphological variation, phenotypic plasticity, or sexual dimorphism in a single species or whether several lineages with incomplete reproductive barriers are present.     

Ontogeny of the cranial musculature in Corydoras aeneus Callichthyidae,Siluriformes

A complete study of the early ontogeny of the cranial muscles of Corydoras aeneus (Callichthyidae) was undertaken and results were compared with those for the loricariid Ancistrus cf. triradiatus. This comparison reveals a high degree of similarity in the ontogeny of both species' cranial muscles. Both species lack a musculus protractor hyoidei, and the musculus intermandibularis posterior is divided into two different parts that have partly obtained a novel function (serving the lower lip) in A. cf. triradiatus. A similar increase in muscular complexity in this species is found in the dorsal constrictor of the hyoid muscle plate. This constrictor gives rise to the same muscles in both C. aeneus and A. cf. triradiatus, but in A. cf. triradiatus the musculus levator operculi later hypertrophies. In C. aeneus the musculus extensor tentaculi forms a single muscle diverging posteriorly, whereas in A. cf. triradiatus the musculus extensor tentaculi differentiates into two separate bundles. Also, a loricariid neoformation is present called the musculus levator tentaculi.     

Morphological and spectrometric analyses of lipids accumulation in a novel oleaginous microalga, Eustigmatos cf. polyphem (Eustigmatophyceae)

Eustigmatos cf. polyphem is a yellow-green unicellular edaphic microalga belonging to the eustigmatophyte. The characteristics of lipids accumulation of E. cf. polyphem grown in a bubble cylindrical photobioreactor under nitrogen-limited conditions was dissected by morphological and spectrometric analyses. Total lipids accumulation rate increased rapidly at early growth phase, with the emergence of many small lipid bodies. Afterwards, lipid bodies became abundant and enlarged primarily because of the progressive accumulation of lipids and the fusion of nearby lipid bodies. Maximum total lipids and neutral lipids content reached up to 60.59 % and 53.08 % of cell dry weight, accompanied with a biomass dry weight 7.9 g/l. E. cf. polyphem is thus referred to as an oleaginous microalga for biodiesel production due to its high biomass and considerable production of oils.     

Middle Cambrian chancelloriids from the Argentine Precordillera

We report, for the first time, and systematically describe chancelloriid from the region, including Chancelloria bella, Allonnia cf. tintinopsis, Al. cf. erromenosa, Al. tripodophora, Archiasterella cf. coriacea, Ar. cf. hirundo, Ar. cf. tetraspina, and Ar. cf. fletchergrully, along with previously reported chancelloriid species (Chancelloria cruceana, C. eros, and Archiasterella sp.). The current chancelloriid fauna is similar in taxonomic composition to the Cambrian Burgess Shale-type biotas and to those of China and South Australia. Based on the sclerite construction, we found that the different articulatory facet types may be used to distinguish Allonnia from Archiasterella, and the number of rays is closely related with the arrangement of sclerite rays. The chancelloriid fauna is found stratigraphically between the Glossopleura trilobite zone of the restricted-shelf facies and the Oryctocephalus trilobite zone of the open-shelf facies, spanning the Wuliuan Stage (Delmaran/Topazan) of the Miaolingian Series, middle Cambrian. This study is significant for better understanding the diversity of this enigmatic and cosmopolitan group in the middle Cambrian warm platform of the Precordillera.     

Systematics,palaeoecology and palaeobiogeography of the Neogene fossil sharks from the Azores (Northeast Atlantic)

The Azores Archipelago is a group of isolated islands located in the North Atlantic Ocean. One of these oceanic islands – Santa Maria – exhibits marine fossiliferous sediments of late Miocene/early Pliocene and also of Pleistocene age. Recent research provided new selachian fossil material, with three new records (Carcharias acutissima, Megaselachus megalodon, and Carcharhinus cf. leucas) increasing the number of fossil sharks reported from the Azores (Santa Maria Island) to seven species (Notorynchus primigenius, C. acutissima, Cosmopolitodus hastalis, Paratodus benedenii, Isurus oxyrinchus, M. megalodon, and C. cf. leucas). So far, no teeth of batoids or small sharks have been found despite the screen-washing of several sediment samples from Santa Maria. The Azorean Mio-Pliocene selachian fauna clearly differs from those described from sediments deposited on continental shelves, in which batoids and small benthic sharks (e.g., scyliorhinids) are usually well represented. During the late Miocene/early Pliocene, subtropical to warm-temperate seas were prevalent in the area of the Azores, as deduced from palaeontological, geological and isotopic data, all indicating a warmer climate than in the present.     

Early ordovician reefs from Argentina: Stromatoporoid vs stromatolite origin

Summary Late Arenigian biohermal reef mounds and biostromes within the shallow-marine platform facies of the upper San Juan Formation of the Precordillera (Western Argentina) represent a new Early Ordovician reef type. The meter-sized reefs are dominated byZondarella communis n.g. n. sp. The new taxon is characterized by domical, bulbous and laminar morphotypes exhibiting growth layers and thin horizontal and vertical as well as intermingled skeletal elements included within different sets. The fossil maybe compared with stromatolites and stromatoporoids but an interpretation as primitive stromatoporoids is favoured.     

Molecular Diversity of Anthracnose Pathogen Populations Associated with UK Strawberry Production Suggests Multiple Introductions of Three Different Colletotrichum Species

Fragaria × ananassa (common name: strawberry) is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l.) is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production.     

Comparative Allometric Growth of the Mimetic Ephippid Reef Fishes Chaetodipterus faber and Platax orbicularis

Mimesis is a relatively widespread phenomenon among reef fish, but the ontogenetic processes relevant for mimetic associations in fish are still poorly understood. In the present study, the allometric growth of two allopatric leaf-mimetic species of ephippid fishes, Chaetodipterus faber from the Atlantic and Platax orbicularis from the Indo-Pacific, was analyzed using ten morphological variables. The development of fins was considered owing to the importance of these structures for mimetic behaviors during early life stages. Despite the anatomical and behavioral similarities in both juvenile and adult stages, C. faber and P. orbicularis showed distinct patterns of growth. The overall shape of C. faber transforms from a rounded-shape in mimetic juveniles to a lengthened profile in adults, while in P. orbicularis, juveniles present an oblong profile including dorsal and anal fins, with relative fin size diminishing while the overall profile grows rounder in adults. Although the two species are closely-related, the present results suggest that growth patterns in C. faber and P. orbicularis are different, and are probably independent events in ephippids that have resulted from similar selective processes.     

Palaeogeographic significance of the giraffid remains (Mammalia,Arctiodactyla) from Cessaniti (Late Miocene,Southern Italy)

The late Tortonian – early Messinian shallow marine sands of Cessaniti area (Monte Poro, Vibo Valentia, Southern Italy) yield marine and continental vertebrates. The best represented taxon is the Sirenian Metaxytherium serresii, while the terrestrial mammal assemblage includes a boselafine bovid, an hexaprotodontid hippopotamus, the giraffids Samotherium cf. boissieri and Bohlinia cf. attica, a rhino and the elephantid Stegotetrabelodon syrticus. Until now, the latter was a species with an exclusive Afro-Arabian distribution and the record of Cessaniti is the first outside Afro-Arabia. Our attention is here focused on the occurrence of Samotherium cf. boissieri and Bohlinia cf. attica, both being species well represented in the Pikermian Biome. Although evidences of the distribution of the genus Samotherium in Late Miocene African assemblages are weak, it is reported at several sites, while a new species of Bohlinia reported in Chad is still debated. At Cessaniti, the co-occurrence of two giraffid taxa typical for the Pikermian biome together with a frankly Afro-Arabic species (S. syrticus), further marks the existence of a land connection between the Cessaniti area and North Africa as well as the evidence of a phase of expansion of the Pikermian Biome into the African continent.     

Stromatoporoid-grade and other sponge fossils from the upper Krol Formation of the Lesser Himalaya (India) Implications for the biotic evolution around the Precambrian-Cambrian boundary interval

Summary A study of fossils in thin sections of a sample from the uppermost Krol E Member in the Mussoorie Hills of the Lesser Himalaya, India, proves the existence of morphologically differentiated calcified sponges within the Precambrian-Cambrian boundary time interval. The sponges, described as Mussooriella kroli n.g., n.sp. and Maldeotaina composita n.g., n.sp. indicate the presence of different organization grades at the Precambrian-Cambrian interval. Mussooriella had a calcareous skeleton consisting of skeletal elements composed of an inner laminated part and a distinct peripheral layer with knobs. Maldeotaina is characterized by a stromatoporoid-grade growth pattern following a thalamid-grade pattern. The stromatoporoidgrade part of the skeletons reminds strongly on skeletal elements common in labechiid Ordovician and younger stromatoporoids. Maldeotaina also shows criteria of Early Cambrian fossils, originally described as stromatoporoids and later excluded from this group and transferred to archaeocyaths. These similarities point to an Early Cambrian age of the fossil-bearing horizon in the topmost Krol E Member. Growth cavities with crypts indicate that the sponges might have contributed to the formation of small metazoan reefs-like structures. Although the study is based on limited material and many interpretations are still tentative, a thorough documentation of the preliminary results seems reliable considering the high potential of the fossils of the upper Krol Formation important source in understanding of early metazoan differentiation.     

Ecdysone-Related Biomarkers of Toxicity in the Model Organism Chironomus riparius: Stage and Sex-Dependent Variations in Gene Expression Profiles

Despite being considered a model organism in toxicity studies, particularly in assessing the environmental impact of endocrine disrupting compounds (EDCs) and other chemicals, the molecular basis of development is largely unknown in Chironomus riparius. We have characterized the expression patterns of important genes involved in the ecdysone pathway from embryos to pupa, but specially during the different phases of C. riparius fourth larval instar, according to the development of genital and thoracic imaginal discs. Real-Time PCR was used to analyze: EcR and usp, two genes encoding the two dimerizing partners of the functional ecdysone receptor; E74, an early response gene induced by ecdysteroids; vg (vitellogenin), an effector gene; hsp70 and hsc70, two heat-shock genes involved in the correct folding of the ecdysone receptor; and rpL13, as a part of the ribosomal machinery. Our results show for the first time stage and sex-dependent variations in ecdysone-responsive genes, specially during the late larval stage of C. riparius. The induction in the expression of EcR and usp during the VII-VIII phase of the fourth instar is concomitant with a coordinated response in the activity of the other genes analyzed, suggesting the moment where larvae prepare for pupation. This work is particularly relevant given that most of the analyzed genes have been proposed previously in this species as sensitive biomarkers for the toxicological evaluation of aquatic ecosystems. Identifying the natural regulation of these molecular endpoints throughout the Chironomus development will contribute to a more in-depth and accurate evaluation of the disrupting effects of EDCs in ecotoxicological studies.