Bivalve borings in Lower Jurassic Lithiotis fauna from northeastern Italy and its palaeoecological interpretation

Random shell sections of the Pliensbachian (Early Jurassic) larger bivalve Opisoma from columns within the Main Post Office building of Ferrara, northern Italy, have been discovered to bear neat clavate-shape boreholes. These boreholes belong to the ichnogenus Gastrochaenolites Leymerie and represent bivalve borings. Opisoma is a subordinate component of the Lithiotis fauna characterised by aberrant shells thriving in tropical lagoonal settings which were widespread throughout the Tethyan and Panthalassa coasts. Although the Lithiotis fauna is well known in the palaeontological literature, no bivalve boring have been so far been formally described. The uniqueness of the morphology, size and substrate of these borings merits the designation of the new species Gastrochaenolites messisbugi ichnosp. nov. which thereby represents the first ichnospecies described from this fauna. The morphology of the boreholes and the included bivalves allows the boring activity to be ascribed to a mytilid bivalve. Palaeoecological and taphonomic analyses allowed the presence of the boreholes to be correlated to the Opisoma mode of life (epifaunal, free-living form) as well as to generally low sedimentation rates and seasonal mesotrophic conditions during an overall oligotrophic regime.

http://zoobank.org/urn:lsid:zoobank.org:act:CCF77B32-D459-4305-BC86-93F228852E50     

Petrography and high-resolution geochemical records of Lower Jurassic manganese-rich deposits from Monte Mangart,Julian Alps

Deposits with unusually high Mn contents sampled at Monte Mangart in the Julian Alps include organic-rich marlstone and black shale with interbedded manganoan and siliceous limestone, which were deposited during the early Toarcian Oceanic Anoxic Event. Mn enrichment during that period has been related to global sea-level change coincident with increasing subsidence rate. The formation of Fe–Mn nodules, marking a hardground at the base of the Monte Mangart section, seems to be triggered by release of Mn from remote hydrothermal vents into a region of relatively elevated submarine topography where oxidizing conditions prevailed. However, very high Mn contents in carbonate phases above the hardground imply an additional diagenetic source of this element in the lower part of this section. The whole stratigraphic sequence (ca 30 m) displays a transition from Mn-rich (up to 8.8%) sediments, in the lower part, to Mn-poor (less than 1.8%) sediments in the middle and upper parts. The drastic decrease in Mn content's up-section is accompanied by a clear decrease in the mean size of pyrite framboids, indicating more intense anoxia/euxinia in the water column. In the presence of Mn²⁺, conditions of high alkalinity induced precipitation of Mn carbonates during early diagenetic processes. Negative δ¹³C_carb values coincident with high Mn contents indicate involvement of organic matter in the mineralization process. The striking similarity of Ce/Ce* and Mn profiles demonstrates that, consistent with redox-chemistry of Mn and Ce under anoxic conditions, Ce³⁺ and Mn²⁺ were mobilized and released into pore water where precipitation of Mn carbonates occurred.     

Biostratigraphic subdivision and correlation of Uppermost Carboniferous/Lower Permian sediments in the Southern Alps: Fusulinoidean and condont faunas from the Carnic Alps (Austria/Italy), Karavanke Mountains (Slovenia), and Southern Urals (Russia)

Summary In order to establish a refined biostratigraphic subdivision and correlation of the Uppermost Carboniferous/Lower Permian deposits of the Southern Alps (Carnic Alps, Karavanke Mountains; Austria/Italy/Slovenia), two major microfossil groups (fusulinoideans, conodonts) were investigated within the same sample. The fusulinoidean species diversity (71 species, including five new species and three new subspecies) and generic composition were reviewed and complemented. Additionally, the data on fusulinoidean assemblages were supplemented by co-occurring conodont faunas (seven species). Accompanying studies on material from the type sections of the Southern Urals (Russia) were made to improve the biostratigraphic correlation with the Russian standard zonation and to discuss paleobiogeographical aspects of the faunal associations. An integrated microfacies analysis of the sampled material in the Southern Alps serves to evaluate the relationships between certain genera and specific microfacies types. The fusulinoidean fauna of the Lower “Pseudoschwagerina” Limestone is of late Gzhelian age. The Carboniferous/Permian boundary is close to the base of the Grenzland Formation, which covers the entire Asselian and a part of the Sakmarian. The Upper “Pseudoschwagerina” Limestone and Trogkofel Limestone are Lake Sakmarian to Artinskian. The studies sequences in the Karavanke Mountains. formerly known as “carbonate and clastic Trogkofel beds”, correlate to the Lower “Pseudoschwagerina” Limestone, respectively with parts of the Grenzland Formation. Due to the lithologic differences, new formation names (Dolzanova Soteska Fm., Born Fm.) were introduced for the so-called “Trogkofel” Limestone along the Dolzanova Soteska. Whereas late Gzhelian/Asselian fusulinoidean faunas of the Southern Alps correspond to the Southern Uralian faunas to a large extent, Sakmarian and Artinskian faunas reveal an increasing divergence in species and genus composition. Climatic as well as geographic barriers may have prevennted the dispersal of Paleotethyan taxa into the Southern Urals. Biostratigraphic correlation of Sakmarian to Artinskian deposits is therefore possible only on the basis of the sparse conodont faunas.     

Lower Cretaceous dinoflagellate cyst and acritarch stratigraphy of the Cismon APTICORE (Southern Alps, Italy)

A pelagic sedimentary succession, virtually complete from the Upper Hauterivian to the Upper Aptian and unconformably overlain by the Middle-Upper Albian p.p., was continuously cored in the Belluno Basin (southern Alps, NE Italy) as part of the APTICORE Program. APTICORE at Cismon Valley penetrated 131.8m of limestones, marls and black shales, with 100% recovery of good quality cored material.One hundred and forty-six samples recovered from the marl and shale beds of the Cismon core were processed and analyzed for palynomorphs. Most of them yielded relatively rich and fairly well preserved assemblages of marine and terrestrially-derived palynomorphs.The results of a qualitative study of dinoflagellate cysts and acritarchs are presented and discussed. The distributions of 150 taxa are tabulated against the chronostratigraphy independently established on the basis of original litho-, bio-, chemo-, magnetostratigraphic investigations and of correlations with extensively studied sections outcropping in the vicinity of the Cismon drill site.The acritarch Pinocchiodinium erbae gen. et sp. nov. is described. Due to its distinctive morphology and extremely constant occurrence also in the black shales of the Selli Level, it is proposed as a marker species for the Aptian sediments of the Tethys.The dinoflagellate cysts Kallosphaeridium dolomiticum sp. nov. and Nexosispinum hesperus brevispinosum subsp. nov. are described from the Upper Hauterivian. Additional taxonomic remarks are made about other dinoflagellate cyst species, including the emendations of Tanyosphaeridium magneticum Davies 1983 and Bourkidinium granulatum Morgan 1975.The biostratigraphic value of selected taxa is discussed and compared with data known both from the Tethyan and Boreal realms. In particular, the extinction of Bourkidinium granulatum emend. is proposed as the best dinoflagellate cyst event for the delimitation of the Hauterivian-Barremian boundary in the Northern Hemisphere. The first appearance datums of Prolixosphaeridium parvispinum and Odontochitina operculata, and the slightly younger last appearance datum of Nexosispinum vetusculum are confirmed as useful biohorizons for recognition of the lower part of the Upper Barremian and hence for the approximation of the Lower-Upper Barremian boundary. The last occurrences of Rhynchodiniopsis aptiana and Phoberocysta neocomica are calibrated in the basal Aptian.     

Brachiopods from the family Ambocoeliidae George (Order Spiriferida) from the Emsian (Lower Devonian) of northeastern Russia

Brachiopods from the family Ambocoeliidae George from the Emsian (Lower Devonian) of northeastern Russia are described: Bisinocoelia despecta sp. nov.; Yakutospirifer gen. nov. with the type species Y. krivensis sp. nov.; Micospirifer gen. nov. with the type species M. simplex sp. nov.; Kolymospirifer gen. nov. with the type species K. optatus sp. nov. (subfamily Ambocoeliinae); Datnospirifer gen. nov. with the type species D. alius sp. nov.; Khalimospirifer gen. nov. with the type species Kh. microscopicus sp. nov.; Gerospirifer gen. nov. with the type species G. normalis sp. nov., and G. gerensis sp. nov.; Dogdospirifer gen. nov. with the type species D. yolkini sp. nov. (subfamily Rhynchospiriferinae).     

First record of Pliensbachian (Lower Jurassic) amber and associated palynoflora from the Monti Lessini (northern Italy)

The fossil record of amber dates back to the Palaeozoic, but it is only since the Mesozoic that amber became relatively common, probably because of the spreading of resin-producing plants. In Italy, the oldest ambers come from the Middle and Upper Triassic of the Dolomites. Cretaceous ambers come from some Albian sites in the Dolomites and from the Coniacian–Santonian of Vernasso, Julian Prealps, northern Italy. Until now, no Jurassic sites with amber have been reported in Italy, and this “Jurassic gap” seems generalized, since there are only a few Jurassic ambers described all over the world. Here, we report the first finding of Lower Jurassic (Pliensbachian) amber from the Bellori locality (Grezzana, Verona Province, Northern Italy). The amber was found in two clayey-coal levels containing plant remains and cuticles, with subordinate bivalves, foraminifera and ostracods. Palynomorphs of the amber levels are dominated by levigate and ornamented spores (ferns) and Circumpolles (conifers). Foraminiferal linings and algal cysts are also present. The freshwater alga Pseudoschizaea is reported for the first time from the Lower Jurassic. The amber shows different kinds of preservation, some peculiar features probably connected with the plant structure, and colours ranging from light yellow to blackish red. Moreover, it includes millimetre-sized wood structures (“mummified wood”) and gas bubbles. Fourier-transform–Infrared, thermogravimetric and differential thermogravimetric analyses were carried out and resulted in a clear characterization of this amber with respect to all others known so far. These data, together with sedimentological observations and fossil content analysis, suggest a coastal palaeoenvironment under rather wet conditions, comparable with the present-day Everglades, with the addition of a monsoonal climate as in the modern southern Asia.     

The taxonomic status of Architipula fragmentosa (Bode) and the family Eoasilidae (Diptera) from the Lower Jurassic

The fossil species Architipula fragmentosa (Bode) comb. nov. (Diptera: Nematocera: Limoniidae) from the German Upper Lias (Lower Jurassic) is redescribed. This species was originally described by Bode (1953) in a new monotypic genus as Eoasilidea fragmentosa and placed in the Brachycera, with Eoasilidea as the type-genus of a new family Eoasilidae. This family is here synonymized with the Limoniidae (Nematocera), and the genus Eoasilidea is synonymized with Architipula Handlirsch .     

Lower and middle Jurassic woods of the Cleveland Basin (North Yorkshire), England

Allochthonous Lower and Middle Jurassic (Pliensbachian–Bathonian) permineralized and charcoalified woods from the Cleveland Basin (North Yorkshire, England) are assigned to five genera of gymnospermous wood ( Cupressinoxylon spp., Taxodioxylon spp., Cedroxylon spp., Xenoxylon Araucarioxylon ) and two species ( Xenoxylon phyllocladoides Araucarioxylon lindlei ). Cell structure is commonly well preserved, particularly in calcified and charcoalified samples, and several features of the growth rings have palaeoclimatological significance. These include distinct growth rings, commonly narrow latewood, low to moderate annual sensitivity and mean sensitivity values, and presence of false rings. Overall, these characteristics reflect fairly consistent growth, both during the growing season and from year to year. Temporally, there is a transition towards narrower rings of more variable width, proportionally wider latewood, and more abundant false rings in Bathonian woods. Water supply is interpreted as the primary limiting control on growth and was probably more restricted in the Bathonian. This is suggested to be a consequence of relatively low sea-level and, more importantly, a genuinely drier climate at this time, manifested as an accentuated annual dry season. In all, the increase in seasonality during the Early and Mid Jurassic in North Yorkshire is compatible with the effects of a developing Mediterranean-type climate.     

Lower Jurassic corals from the Pamir Mountains,Central Asia

The paper describes new Lower Jurassic corals from the South-Eastern Pamir Mountains (Tajikistan) and interprets their relationships with contemporaneous West Tethyan corals. Taxonomic similarities with Pliensbachian European and North African faunas indicate a Pliensbachian age for this fauna, which was previously considered to be of Hettangian/Sinemurian age. Together with the taxa earlier described from the Pamirs, this fauna consists of 30 species of 25 genera, including Triassic holdover genera such as Stylophyllopsis, Phacelostylophyllum and Eocomoseris. The bulk of the fauna represents new Jurassic genera: Alichurastrea, Eomicrophyllia, Guembelastreomorpha, Gurumdynia, Pinacomorpha, Protostephanastrea, Psenophyllia, Sedekastrea and Stylimorpha. Earlier coral studies of the region concerned the genera: Archaeosmilia Melnikova, 1975, Archaeosmiliopsis Melnikova, 1975, Cylismilia Roniewicz, 1988, Pachysmilia Melnikova, 1989, and Prodonacosmilia Melnikova in Melnikova and Roniewicz, 1976. Two species that were considered to belong to the genus Cylismilia, are redescribed and reclassified in the genera Psenophyllia, and Archaeosmilia Melnikova, respectively.     

A New Family Of Coleoids From The Lower Jurassic Of Osteno, Northern Italy

The discovery of well preserved and almost complete fossil coleoid cephalopods near Osteno in northern Italy has allowed the original study of a single specimen by Pinna (1972) to be enhanced. The unusual structure of the ten arms, showing a clear differentiation in the shape of the arm hooks (long and thin on six arms and short and stocky on the other four), is a distinctive character which is not present in any Jurassic family of coleoids known to date. We distinguish two new genera: Ostenoteuthis, with the species O. siroi sp. nov., and Uncinoteuthis, with the species U. cuvieri sp. nov. The new family Ostenoteuthidae (Order uncertain) is erected for them. The systematic position of this family within the fossil coleoids is discussed.     

Sponge communities from the Lower Liassic of Adnet (Northern Calcareous Alps, Austria)

The lower slope of the drowned Alpine Adnet Reef was recolonized in Hettangian time by sponge communities of hexactinellid (hexactinosid and lyssacinosid) taxa and a few demosponges. Special taphonomic processes caused an excellent preservation of these sponges. The preservation allows to define several growth forms and to study original spicule configurations of the mainly non-rigid skeletons. Sponge faunas of presumably similar associations are known from adjacent basins, but only by isolated spicules of completely collapsed specimens. In Adnet the sponges are embedded in biodetrital limestones of the Schnöll Formation. Orientation and distribution of the sponges reflect autochthonous faunas that have been mixed with dislocated individuals by local water currents. The predominance of erect sponge types indicates intermediate sedimentation rates and/or occasional high-energy events. Sponge types and community structures are comparable with those ones from Middle Paleozoic mud mounds. Several hiatuses, mostly characterized by ferromanganese crusts have been kept free of sponge settlement. Carbon stable isotopes of the sponge-rich sequence show a small negative δ¹³C_carb excursion that covers the period from Lower Hettangian to Lower Sinemurian.This revised version was published online in May 2005 because several displayed passages had been inadvertently deleted in the original published version.     

Non-marine biota from the Lower Permian of the central Southern Alps (Orobic and Collio basins, N Italy): a key to the paleoenvironment

The Lower Permian in the central Southern Alps yields an important low-diversity fossil assemblage which was deposited in a varied continental setting, showing mainly alluvial fan to lacustrine and, locally, playa-like floodplain environments. The present study is not taxonomical and its objective is to make a first report of new invertebrate organisms and trackways discovered in the Orobic and Collio basins. Such a fossil record, which comprises freshwater jellyfishes, arthropod tracks, stromatolites, algae and other organisms, will further our knowledge about the local and regional geological history of the central-western Southern Alps and improve our understanding of Early Permian palaeoenvironments. On the whole, in both intramontane basins the ichnodiversity and fossil content decreases from a stratigraphic lower portion, mainly lacustrine and alluvial, towards an upper one, characterised by coarse alluvial deposits to floodplain fines. On the basis of both the already known palaeontological data from the two basins, mainly macroflora and tetrapod footprint associations, and the recently discovered taxa, we tried to make reliable palaeoenvironmental inferences and, possibly, hypothesise on a climatic change, which could have occurred during the Early Permian.     

Middle to Late Jurassic radiolarians from Sicily (Italy)

Middle and Upper Jurassic radiolarian faunas from two sections of Sicily are compared with the previously proposed zonations. The ages of the faunas are estimated by correlation with these zonations and by concurrent range zone. The faunas could be assigned to the Bathonian or earlier late Tithonian or early Berriasian. Two new spumellarian species (Bernoullius furcospinus andBernoullius rectispinus) from Middle Jurassic are described.     

Lavinipes Cheminii Ichnogen., Ichnosp. nov., A Possible Sauropodomorph Track from the Lower Jurassic of the Italian Alps

A new ichnotaxon is described from the Lower Jurassic (Upper Hettangian-Lower Sinemurian) carbonate tidal flats on the central-eastern Italian Alps. The narrow-gauge trackway is that of a large quadrupedal dinosaur. The pes is functionally tetradactyl with three rounded antero-medially directed digits, and the manus is pentadactyl. This quadrupedal form is close to Otozoum and Pseudotetrasauropus jaquesi both traditionally related to sauropodomorph trackmakers. The similarity with Otozoum is so marked that Lavinipes and Otozoum could be cogeneric. But the overall evidence today is that the Otozoum trackmaker was generally bipedal, whereas the trackmaker of L. cheminii is fully quadrupedal. The manual prints of L. cheminii show five short clawless digits and are different from the tetradactyl slender toed manual prints of Otozoum. The possible sauropodomorph affinity of the L. cheminii trackmaker is here discussed with an attempt to a revision of the Late Triassic-Jurassic tracks which have been traditionally related to sauropod and prosauropod.     

Mire vegetation in the Apuanian Alps (Italy)

Mire vegetation in the Apuanian Alps (N Italy) is analyzed from the phytosociological and the synecological points of view. Three vegetation types are delimited by numerical methods and compared with mire communities of the Alps and the Apennines. Furthermore, a chorological evaluation of this vegetation is attempted on a floristical basis.     

A generic revision of the Dorvilleidae (Polychaeta), with six new species from the deep North Pacific

PETER A. JUMARS
The Dorvilleidae are divided into eight genera: Dorvillea, Schistomeringos (new name), Protodorvillea, Meiodorvillea (new genus), Exallopus (new genus), Ophryotrocha, Parophryotrocha , and Apophryotrocha (new genus). Periodic maxillary replacement is found to occur in a manner which makes many often cited maxillary characters taxonomically unreliable. Therefore, the pharyngeal characters of all the type-species are redescribed or newly described. The discovery of new forms and the present interpretation of hard jaw parts permit construction of a phylogenetic scheme with Dorvillea as the most primitive genus containing living species. Suggestions are given for the advantageous use of the phenomenon of maxillary replacement in autecoiogical investigation.
Evidence is presented against the cosmopolitan distribution of Schistomeringos rudolphi , a species often noted in nearshore pollution studies. Newly described species are Dorvillea batia, Schistomeringos mediofurca, Meiodorvillea apalpata, Exallopus cropion, Ophryotrocha profunda , and Apophryotrocha mutabiliseta , all from the deep North Pacific. A key to the genera is provided, as are listings of all the known species within each genus.     

Welwitschiaceae from the Lower Cretaceous of northeastern Brazil

Welwitschiaceae, a family in the Gnetales, is known today from only one extant species, Welwitschia mirabilis. This species is distributed in the Namibian desert, along the western coast of southern Africa, about 10 km inland from the coast. Very little is known about the fossil record of this family. Lower Cretaceous megafossils of various organs, assigned to Welwitschiaceae, are presented here. These fossils include young stems with paired cotyledons attached (Welwitschiella austroamericana n. gen. et sp.), isolated leaves (Welwitschiophyllum brasiliense n. gen. et sp.), and axes bearing male cones (Welwitschiostrobus murili n. gen. et sp.). They were collected in the Crato Formation, which is dated by palynomorphs and ostracods as Late Aptian (114 to 112 million years ago). These sediments are exposed in the Araripe Basin of northeastern Brazil. This study brings together new information of the megafossil record of Welwitschia-like plants and also reports of pollen said to be similar to that of Welwitschia from Lower Cretaceous sediments.     

New Lower Devonian brachiopods of the family Reticulariidae Waagen (order Spiriferida) of northeastern Russia

New Lower Devonian brachiopod taxa of the family Reticulariidae (order Spiriferida) are described from northeastern Russia: Havlicekospirifer gen. nov. with the type species H. mirabilis sp. nov. (subfamily Reticulariinae) and Pavlovispirifer gen. nov. with the type species P. pelagicus sp. nov. (subfamily Rhenothyridinae).