Hydrothermal vent myodocopid ostracods from the Eifelian (Middle Devonian) of southern Morocco

A monospecific assemblage of myodocopid ostracods has been found in the Middle Devonian of a unique hydrothermal vent system of Hamar Laghdad (eastern Anti-Atlas, southern Morocco), which developed over a submarine eruption of basaltic rocks. This fauna has been recovered from a neptunian dyke representing the sediment infill of an Eifelian venting fissure discovered in the central part of Hamar Laghdad. The assemblage consists of thousands of relatively large shells forming a coquina layer in which the valves are disarticulated, perfectly washed, well sorted and stacked into each other. Their orientation points to transport due to fluids migrating in the vent system. The ostracod specimens, on the base of the general outline, the presence of rostrum and rostral incisure is assigned to the order Myodocopida. The new genus and species Hamaroconcha kornickeri is proposed, most likely representing a new family. Its carapace morphology gives no clear clue to its mode of life; however, a relatively long rostral incisure may suggest that frontal appendages of this species were sufficient for active swimming. Therefore, a nectobenthic lifestyle is postulated for H. kornickeri nov. gen., nov. sp. Isotope data from the sediment infill provide evidence for the activity of hydrothermal fluids.     

Isolated theropod teeth from the Kem Kem Beds (Early Cenomanian) near Taouz, Morocco

Thirty-seven well-preserved, isolated theropod teeth from the Early Cenomanian Kem Kem beds, Morocco, are identified by using morphometric data and direct comparison with teeth previously described in the literature. Direct comparison reveals that four different morphotypes (MT 1–4) are present in the sample. The teeth of MT 1 are characterised by unserrated carinae and belong to spinosaurid dinosaurs. The teeth of MT 2–4 have serrated carinae, and our data analysis indicates they are of carcharodontosaurid, dromaeosaurid, and abelisaurid origin. Three types of crown enamel ornamentation are present among the teeth of MT 1, which implies that, apart from Spinosaurus aegyptiacus STROMER 1915, more than one species of spinosaurine theropods may be present in the Early Cenomanian of Northern Africa. Our results also confirm the occurrence of abelisaurids, dromaeosaurids, and carcharodontosaurids in Morocco.     

Radiolaria as indicators of upwelling processes: The Peruvian connection

In the sediments along the coastal region of Peru, certain radiolarian species have preferences to waters associated with upwelling. Such is the case forPolysolenia murrayana in the upwelling areas “fed” by equatorial water and forCenosphaera (?) sp. in the upwelling areas “fed” by temperate (Subantarctic) water.Cycladophora (?)davisiana appears to “frame” the upwelling centers, suggesting that it prefers regions near thermic fronts.The down-core records of these species, as well as records of quartz and organic carbon, are depicted in three¹⁴C andδ¹⁸O dated cores, located along the Pacific coast of South America, between 11° and 13°S. They suggest that both the eolian and oceanic circulation were more intense during the last glacial stage (approximately between 33,000 and 11,000 years ago) than during the present postglacial. At these latitudes, the intensification in circulation was not only accompanied by an increased coastal upwelling and in turn by an increased primary productivity, but also by a larger supply of Temperate waters to the area.     

Pollen analysis of honeys from the Gharb region (NW Morocco)

The pollen spectra in 18 honey samples from the Gharb region (Northwest of Morocco) have been studied. The samples were collected directly from the beekeepers, both professional and amateurs. The results show that nectar was the main honey source in this region, although one forest or mixed honey was detected. Seven samples belonging to the Class I, five to the Class II and six to the Class III were found. In all the samples some honeydew indicator elements were detected, with HDEN/NPGN= 0.005-1.38. By the qualitative results 58 pollen types belonging to 28 families were identified. Some species of Lythrum , Eucalyptus , Trifolium , Citrus , Mentha , Apiaceae and Scrophulariaceae are the main nectar sources,and some of Asteraceae, Quercus sp., Olea europaea , Plantago sp. and Fragaria 2 ananassa are the most important pollen sources. At least 14 unifloral honeys (c. 77%) from Citrus , Eucalyptus , Lythrum , Mentha and Teucrium were detected.     

Growth forms and palaeoenvironmental interpretation of stromatoporoids in a Middle Devonian reef, southern Morocco (west Sahara)

Growth forms of well-preserved stromatoporoids, including genera Actinostroma, Stachyodes, and Stromatopora, are described for the first time from the Devonian Sabkhat Lafayrina reef complex of southern Morocco (west Sahara), one of the best exposed Middle-Devonian stromatoporoid-dominated fossil reefs. Three facies types representing the well illuminated fore-reef, reef-core and transition to back-reef facies display the distribution and growth of stromatoporoids in a high latitude setting at 40–50° south of the palaeoequator. Stromatoporoids are largely in growth position and reflect the well-preserved reef architecture. Although outcrops are low topography, the reef's prominent profile is indicated by presence of spur and groove form and a clearly defined reef margin. Stromatoporoids are mostly laminar and domical forms, with little evidence of ragged margins, and indicate normal turbulence shallow waters, with low sediment deposition.     

Evolution of antennules of cytheroidean ostracods (Crustacea)

Phylogenetic analysis and fossil records indicate that antennules with whip-like setae are the most plesiomorphic state in cytheroidean ostracods and that antennulae with claw-like setae are derived from antennulae with whip-like setae. Character distributions on the 18S rDNA molecular phylogenetic tree suggest that two phenotypic features of cytheroidean antennules (W/L ratio and claw-like/whip-like setae) have morphological plasticity. These features have evolved as an ethological adaptation rather than due to phylogenetic constraints such as the evolution of shell outline in cytheroideans. However, the species of the Leptocytheridae–Trachyleberididae clade generally have stout, robust antennules, indicating a phylogenetic constraint. The character state of setae (claw/whip) in cytheroidean ostracods is reflected more through their ethology than the W/L ratio of the antennules. On the basis of the present analysis and the fossil record, diversification in the morphology of the antennules seems to have occurred during the early Mesozoic.     

Patagonian ostracods as indicators of climate-related hydrological variables: implications for paleoenvironmental reconstructions in Southern South America

Different precipitation regimes across Patagonia generate an environmental gradient that is expected to reflect upon the solute composition and concentration of lake water through the ensuing differences in water balance. In turn, this hydrochemical gradient could influence the occurrence and distribution of ostracods in the area. A cluster analysis on hydrochemical data of 36 Southern Patagonian waterbodies shows that low salinity, bicarbonate-dominated waters characterize Andean and ecotonal lakes, located in the wetter part of the precipitation gradient, while their steppe counterparts, which receive a much lower precipitation input, are more saline, enriched in all major anions and sodium-dominated. Kruskal–Wallis tests followed by Mann–Whitney pairwise comparisons show statistically significant differences in the ostracod species each water type hosts, with L. patagonica, E. cecryphalium, P. smaragdina and P. incae being found in the more dilute waters characteristic of Andean and ecotonal lakes and Limnocythere rionegroensis in the mesohaline, evaporatively evolved waters typical of steppe lakes. Other species studied do not appear to have such distinct distributions, having been found throughout the range of conditions studied. These findings promote the use of the aforementioned ostracods as semi-quantitative paleohydrological indicators, which could improve paleoclimatic reconstructions in Patagonia.     

Algae as depth indicators in the Silurian of the Oslo region

Specimens of Girvanellu sp. are described for the first time from the Oslo region, Norway. The specimens discussed here occur in Lower Llandoverian biomicrites in the central part of the Oslo region (Bærum/Asker). The distinct association between Girvanella sp. and other faunal elements in the succession provides important new information on the depth ranges of Lcwer Silurian brachiopod communities.     

Spatial structure of the zooplankton community in the Cabo Frio region (Brazil) influenced by coastal upwelling

Cabo Frio area (Central-southern Brazilian littoral) is characterized by a coastal upwelling due to prevailing E-NE winds, mainly during the spring-summer season. The geographic distribution of the zooplankton was described in order to separate ecological areas in terms of specific communities. Cluster analysis by weighted pair-group method (WPGA) and principal component (PC) analysis was performed on the most important hydrological parameters and zooplankton taxa. The first PC, explaining 38% of the total zooplankton variability, represented the influence of the nearshore-offshore gradient. Zooplankton communities and ecological areas were defined as follows:

1. nearshore neritic: the richest region with more than 5 000 org. m-3. In this very narrow nearshore region we observed 3 groups of taxa deliminated by upwelling effects and trophic conditions: a) Ctenocalanus vanus, Penilia avirostris, Calanoides carinatus and Copepod larva, all herbivorous species associated with the phytoplankton blooms in the upwelling zone; b) Creseis acicula and Temora stylifera; c) Siphonophora, Chaetognaths and a high diversity of Copepoda dominated by Coryceus amazonicus, C. giesbrechti, Eucalanus pileatus, Clausocalanus acuicornis, all carnivorous or omnivorous feeders representing a high degree of complexity of the ecosystem.
2. offshore neritic: characterized by appendicularians, this region constitutes an intermediate zone between coastal and oceanic waters.
3. oceanic: occupied by the Brazil Current where zooplankton is poor, but diversified, with typical copepods from tropical warm water: Clausocalanus furcatus, Mecynocera clausi, Corycella gracilis, Oithona setigera, Coryceus typicus, Oncea conifera, Undinula vulgaris, Calocalanus pavo, Haloptilus longicornis, Lucicutia flavicornis.

     

Ontogeny and phylogeny of Upper Cenomanian rotaliporids (Foraminifera)

The fossil record of planktonic foraminifera is a key source of data on the evolution of marine plankton. One of the most distinctive groups of Cretaceous foraminifera, the rotaliporids, widely used as a stratigraphic index, has always been considered to be a monophyletic clade. New data on the coiling direction and persistent morphological features of the late rotaliporids from the Upper Cenomanian of the Western Interior Seaway, USA, and the Vocontian Basin of southeast France is used as a phylogenetic proxy. Dealing with key morphological features, the coiling pattern of these keeled morphotypes proves that the rotaliporids group is polyphyletic and composed of Thalmanninella, that displays a dextral-coiling preference, and Rotalipora s.s., that have a proportionate-coiling mode. The stratigraphically youngest rotaliporids with keels co-occur with globular forms; and all morphologies transitional between these morphotypes are observed. The ontogenetic relationships between them are investigated, indicating that loss of the keel was a selective advantage that enabled those rotaliporids to remain in the surface water, thereby avoiding the expansion of the oxygen minimum zone. Two species are observed: Thalmanninella multiloculata and Rotalipora planoconvexa. These species are interpreted as having arisen by neoteny from Thalmanninella greenhornensis and Rotalipora cushmani respectively.     

First record of ostracods (Crustacea) in Baltic amber

Ostracods were found in two pieces of Baltic amber for the first time. The animals belong to the freshwater genus Cyclocypris. Since Baltic amber was formed during Eocene times in southern Scandinavia, the age of the specimens is estimated at 42–54 million years. As aquatic organisms, ostracods are seldom trapped in amber; it is considered that one specimen, already dead and dried, was either blown onto sticky resin on a plant stem, or washed there by a high flood level, while the other was probably splashed, alive, in a drop of water against the flowing resin, again probably during a flood. Associated faunal remains, including other crustaceans, suggest a coastal palaeoenvironment with some marine as well as freshwater influence.     

An early meromictic stage in Lobsigensee (Switzerland) as evidenced by ostracods and Chaoborus

Lobsigensee is a small kettle on the western Swiss Plateau in a tectonic depression of the tertiary Molasse. At present its maximum depth is 2.7 m. Analysis of ostracods and other organisms (Chaoborus) from a 13 m core indicates that the lake became meromictic during the Bølling and returned again to a holomictic stage during the Boreal when the lake was approximately 10 m deep. The meromictic period is characterized by the disappearance of ostracods — especially of Cytherissa lacustris and Limnocythere sanctipatricii — and the appearance of Chaoborus, whereas the onset of the second holomictic stage is marked by the recolonization of the profundal zone by ostracods not present before in the lake (Metacypris cordata, Darwinula stevensoni). A very similar case of fossil meromixis has been found in Kleinsee in Carinthia.     

The Tipulidae (Diptera) of northern Morocco with a focus on the Rif region,including the description of a new species of Tipula (Lunatipula) and an updated checklist for Morocco

An overview of the Tipulidae known to occur in northern Morocco with an emphasis on the Rif mountains is given, incorporating new distribution data based on recently collected material in the area. Dolichopeza (Dolichopeza) hispanica, Tipula (Lunatipula) subpustulata, and Tipula (Yamatotipula) afriberia afriberia are recorded for the first time for the Rif. Tipula (L.) stimulosa Mannheims, 1973 and T. (Vestiplex) vaillanti vaillanti Theowald, 1977 are reported for the first time for the Rif and Morocco. Tipula (Lunatipula) pseudocinerascens Strobl, 1906 and Tipula (Savtshenkia) confusa van der Wulp, 1883 are recorded for the first time for the Rif, Morocco and North Africa. A new species of the subgenus Lunatipula, T. (L.) pjotri n. sp., is described and illustrated. Nephrotoma exastigma, previously reported for the Rif, seems to be absent in Morocco. Reports of Tipula (Emodotipula) obscuriventris Strobl, 1900 for Morocco actually refer to T. (E.) leo. This brings the number of Tipulidae for Morocco to 39 species and for the Rif to 28. An updated checklist of the Tipulidae of Morocco is provided.     

Late Quaternary development of the Java upwelling system (eastern Indian Ocean) as revealed by coccolithophores

The paleoceanographic potential of coccolithophores was used to decipher the paleoproductivity changes in the eastern Indian Ocean during the past 300,000 years. Core SO139-74KL was taken at the seaward limit of a fore-arc basin of the Indonesian continental shelf located beneath the Java upwelling system. Coccolithophores occur in all samples, and total coccolith concentration exhibit distinct variations over the entire section. Peak abundances occur every 20,000 to 25,000 years with the highest peak at isotope stage 7. Abundances increase during the glacials but peak abundances also occur during interglacials. The preservation of coccoliths is good to moderate in most of the samples. The most abundant species is Florisphaera profunda with a mean relative abundance of 41.5% followed by Gephyrocapsa ericsonii and Emiliania huxleyi (EhuxGeric) and Gephyrocapsa oceanica. These four taxa dominate the assemblage throughout the core, forming on average 90.5% of the total assemblage. The species composition suggests that warm tropical conditions prevailed throughout the investigated time period indicating that temperature was not the driving force for the assemblage variations at this site. The geologic record for present-day and Holocene oceanographic conditions seemed to be predominantly characterised by high productivities in combination with an unstable water column. Indications for oligotrophic open ocean conditions were sparse. However, during most of the year oligotrophic conditions prevail and upwelling recurs only for a short time period but upwelling indicating proxies dominate the geological record. A contrasting fully oligotrophic scenario characterised by peaks in the abundances of total coccolithophores, Umbellosphaera irregularis, and in the percentage ratio of EhuxGeric to G. oceanica can be seen with a periodical recurrence every 20,000 to 25,000 years. Synchronously the records of the high productivity indicators total organic carbon and G. oceanica are characterised by distinct minima. We believe that upwelling was totally cut off during these times and oligotrophic conditions with a pronounced water column stratification prevailed throughout all seasons. An obvious correspondence between the shut down times of upwelling and insolation minima suggests that surface water conditions were driven by orbital forcing.     

Microzooplankton grazing of phytoplankton in a tropical upwelling region

We measured grazing by herbivorous zooplankton (<200 μm fraction) in coastal and slope regions of the South Brazil Bight. Using the dilution technique, we performed nine experiments during the austral summer, when nutrient-rich South Atlantic Central Water is present on the shelf, and five during winter. These experiments provide the first estimates of microzooplankton grazing in the western South Atlantic Ocean. Model II regression showed a strong relationship between phytoplankton intrinsic growth rates and grazing, with a slope of 0.64 (±0.28; 95% confidence interval) indicating that microzooplankton grazing could account for the majority of phytoplankton mortality. Both phytoplankton growth and microzooplankton grazing were higher during the summer upwelling season, compared to winter. For the two experiments that were conducted in oligotrophic slope water, grazing accounted for >80% of phytoplankton production. A comparison of incubations with and without added inorganic nutrients showed no consistent stimulation of phytoplankton growth (slope of enriched versus unenriched treatments not significantly different from 1). Estimates from microscopic counts of heterotrophic organisms >10 μm indicated that copepod nauplii comprised the largest share of the microzooplankton biomass (mean 62.4 ± 5.8% SE). Grazing estimates were not correlated with microzooplankton biomass, whether or not nauplii were included, suggesting that most of the grazing was done by nano-sized zooplankton. Electronic Supplementary Material Electronic supplementary material is available in the online version of this article at and is accessible for authorized users. Handling editor: S. Wellekens     

First occurrence of the Ichnogenus Selenichnites from the Middle Jurassic Strata of the Skoura Syncline (Middle Atlas,Morocco); Palaeoecological and palaeoenvironmental context

Mesozoic strata of North Africa yield the first occurrence of the ichnogenus Selenichnites. The trace fossils occur on the top surface of a sandy carbonate deposit in the axis of a Middle Atlas syncline (Skoura Syncline, NE Morocco). The ichnofossil-bearing horizon belongs to the Late Bajocian–Early Bathonian Ich Timellaline/Bou Akrabene Formation. The trace fossils are crescent-shaped and the best preserved exhibits a posterior central axial impression (possible telson tail impression). They are interpreted as feeding burrows (fodinichnia) or hiding depressions of Xiphosurids or Limulids (horseshoe crabs) on a sandy carbonate substrate beneath a veneer of muddy deposits. The sedimentological character suggests a relatively protected shallow water subtidal palaeoenvironment preceding the Bathonian regression of the Atlas domain. This discovery provides the first evidence of xiphosurans or xiphosuran-like organisms inhabiting the southern shores of the Tethys in the Middle Jurassic.     

Stoneworts (Characeae) and associated macrophyte species as indicators of water quality and human activities in the Pays-de-la-Loire region, France

Two ecologically and morphologically distinct forms of Furcellaria lumbricalis and loose form of Coccotylus truncatus were experimentally tested to obtain information on the growth rates and influence of the habitat depth on their eco-physiological activity. Incubations were carried out in the area inhabited by a loose F. lumbricalis–C. truncatus community in Kassari Bay of the West-Estonian Archipelago Sea, the NE Baltic Sea. During the incubation period (20.04–21.10.2002) loose forms of F. lumbricalis and C. truncatus showed similar dynamics of both growth rate of biomass and primary production while attached form of F.␣lumbricalis had, as a rule, significantly lower growth rate and primary production values. The highest eco-physiological activity was recorded from the shallowest incubation depth (4 m) for all three algal forms. All three tested algal forms had similar pattern of growth during the incubation period – highest growth rates were detected in spring and early summer while during the rest of the incubation period algal biomass was in a steady state when production balanced degradation processes.     

Global diversity of ostracods (Ostracoda,Crustacea) in freshwater

There are close to 2,000 subjective species and about 200 genera of Recent non-marine Ostracoda. Together, Cyprididae (1,000 spp.) and Candonidae (c. 550 spp.) represent more than 75% of the extant specific diversity; the remaining 11 families comprise the other 25% of the species. The Palaearctic region has the highest absolute non-marine ostracod diversity, followed by the Afrotropical. The Australian region has the highest relative endemicity. About 90% of the species and 60% of the genera occur in one zoogeographical region only. This means that all the biological mechanisms which lead up to efficient dispersal and which are present in at least part of the non-marine Ostracoda (e.g. brooding, drought-resistant eggs, parthenogenesis) have not induced common cosmopolitan distributions in ostracods. Several habitats are hotspots for ostracod diversity and endemicity. For example, it appears that the ancient lakes hold up to 25% of the total ostracod diversity. Other speciation-prone habitats are groundwater, temporary pools and Australian salt lakes; in the latter two instances, cladogenesis has often been paralleled by gigantism. The present ostracod diversity results from 9 to 12 separate invasions of the non-marine habitat, starting about 400 Myr ago. Genetic diversity can be very different in different species, mostly, but not always, related to reproductive mode. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment