Genesis and environmental significance of Upper Cretaceous shell concentrations from the Cauvery Basin,southern India

Upper Cretaceous shallow marine calcarenites of the Upper Campanian–Maastrichtian Kallankurichchi Formation from the Cauvery Basin of southeastern India are rich in shell concentrations dominated by large bivalves with minor admixtures of brachiopods, bryozoans, and larger foraminifera. Rarely, these concentrations occur as lenses or pavements, but usually as beds 10 to 200 cm thick. Depending on the dominant skeletal elements, five types of shell concentrations can be distinguished: Isognomon, Pycnodonte, Ceratostreon, inoceramid (?Platyceramus, Cataceramus), and polyspecific concentrations. These shell concentrations occur in various preservational states which reflect the gradual mixing and mechanical destruction of former communities. Analysis of the taphonomic signatures of their components and of the biofabric suggests that storm-induced waves and currents, reduced sediment input, the settling behaviour of taxa, and a high rate of production of biogenic hardparts were responsible, in varying degrees, for the formation of the various shell concentrations. Accordingly they can be classified as storm wave, proximal tempestite, and primary biogenic concentrations. The shell concentrations formed below fair weather wave base in shallow, subtropical, low-stress environments.     

Tafonomía de bivalvos holocenos en la costa del estuario de Bahía Blanca, Argentina

In the Bahía Blanca Estuary (Argentina), Holocene deposits are fossiliferous sand ridges originated by the last transgressive-regressive marine event. By means of ternary taphograms applied on valves of Brachidontes rodriguezi a taphonomic analysis was carried out in two ridges, both in the external and internal estuary area. Six taphonomic attributes were considered. The disarticulation and the fragmentation are higher in the external ridge, whereas the bioerosion and incrustation, both barely manifested, are similar in the two environmental settings. In the outer deposit, as much the abrasions as the dissolution of the shells are more intense. Genetically, it is considered that these shell concentrations were originated by multiepisodic storm events. Based on the taphonomic analysis, it arises that in the generation of the internal ridge waves of moderate energy with different sorting degrees prevailed, whereas in the formation of the external deposits waves of greater energy with smaller sorting capacity prevailed.     

Taphonomy and palaeoecology of Hauterivian–Barremian nerineoid shell beds from the Neuquén Basin,west‐central Argentina

Nerineoid shell beds are described for the first time from Lower Cretaceous deposits of southern South America. These come from carbonates near the top of the Agrio Formation in southern Mendoza Province, west‐central Argentina. To envisage the origin of the nerineoid shell beds, a taphonomic study was carried out, which indicated that these represent within‐habitat time‐averaged, primary sedimentological concentrations with a secondary biogenic imprint related to a relatively high local production of nerineoid shells. The associated palaeoenvironments were studied through a facies analysis of the carbonate succession including the shell beds. The carbonates were deposited in a homoclinal ramp system and depict a shallowing upward trend from mid to inner ramp. The individuals lived and accumulated in oolitic shoals within the inner ramp, in a shallow, well‐lit, high‐energy setting above fair‐weather wave base. Substrate was oxygenated and loose. The nerineoids are shown to belong to one species of the genus Eunerinea, and through the functional morphology of the shells they are tentatively interpreted as infaunal or semi‐infaunal. It is suggested that the recorded monospecific nerineoid shell beds indicate that the palaeoenvironmental conditions may have been favourable for the development of abundant populations of these gastropods in the northern part of the Neuquén Basin during a short time interval in the Hauterivian–Barremian boundary. This could have been related to a brief warming episode, but other factors may have also been involved. □Argentina, Early Cretaceous, Gastropods, nerineoids, Neuquén Basin, shell beds, taphonomy.     

The Tournaisian (Early Carboniferous) of the Kahanag section (central Alborz; northern Iran); biostratigraphy with calcareous algae and foraminifers; palaeobiogeographic implications

The Tournaisian beds of the Kahanag section in central Alborz (northern Iran) are described. This Tournaisian is probably complete and continuous from MFZ1 to MFZ8 biozones; nevertheless, (1) the base is only lithostratigraphically characterized, (2) the biozones MFZ1 to MFZ5 cannot be differentiated, and (3) in topmost beds, Eoparastaffella simplex indicative of the basal Viséan have not yet found. This Tournaisian is subdivided into a local lower Tourmaisian (MFZ1-MFZ5) showing a poor assemblage of monolocular and bilocular foraminifers, and a local upper Tournaisian where the biozones MFZ 6 and 7 are precisely defined. In Kahanag, MFZ 6 is characterized by the FO of Eotextularia diversa; MFZ 7 is the range-zone of Darjella monilis; and the base of MFZ8 is marked by the appearance of Eoparastaffellina. The biozone MFZ 8 is particularly developed in Kahanag, and represents almost one third of the field-section; therefore, a local subdivision is proposed, especially in order to characterize an upper MFZ8 subbiozone. Additionally, some algae of the section are accurately described; especially a trio which might be characteristic of the latest Tournaisian in Iran, (1) the unilayered “Koninckopora” mentioned for the first time in Iran; (2) a new genus of dasycladaleans Kahanagella n. gen.; and (3) a new genus of palaeoberesellaceans, Oblikamaena n. gen. More classical Algospongia (incertae sedis algae) are briefly mentioned Issinella, Crassikamaena, Kamaena, Palaeoberesella, Exvotarisella, Pseudostacheoides, Sinustacheoides and Stacheoides. Regionally, the new genus Kahanagella might be an important palaeobiogeographic marker because it was also discovered in the Tabas Block, while it seems absent in the adjacent, well-known areas (Taurus, southern Urals, Kazakhstan). Perhaps, Kahanagella might permit to reconstruct the initial geography of the latest Tournaisian Iranian platforms. Oblikamaena elbursica n. gen. n. sp. is an endemic taxon for the moment but might become also palaeobiogeographically interesting. Finally, the whole foraminiferal and algal Tournaisian assemblage permits to propose a reconstruction of the initial palaeoposition of the Iranian terranes prior to the progressive assemby of the Cimmerian terranes.     

Upper Pliocene bivalve shell concentrations from the Lower Chelif basin (NW Algeria): Systematics,sedimentologic and taphonomic framework

Sedimentologic and palaeontological investigation of the Upper Pliocene Slama Formation in the Lower Chelif Basin (NW Algeria) led us to collect important bivalve assemblages for taxonomic and taphonomic purposes. A rather comprehensive inventory list of Upper Pliocene bivalves from northwestern Algeria is now available and consists of 30 species, 17 of which are extinct ones. Four principal taphonomic attributes were analysed: bioerosion, encrustation, fragmentation, and abrasion. Physical and biogenic sedimentary structures are used for palaeoenvironmental interpretations. The taphonomic, sedimentologic and ichnological characteristics of most of the deposits suggests they originated from discontinuous processes of winnowing and bypassing of sediments, probably due to the action of storms in shallow waters, mainly in the shoreface depositional environment. The bivalve assemblage is dominated by disarticulated valves and displays significant taphonomic alteration in the shells. Sclerobionts traces in shells particulary affect the oyster shells. Bioerosion traces are predominately those of clionid sponges (Entobia isp.), polychaetes (Maeandropolydora isp. and Caulostrepsis isp.), bivalves (Gastrochaenolites isp.), and of predatory gastropods (Oichnus isp.). Among the sclerobionts, the identified encrusters were juvenile oyster recruits, barnacles, polychaetes (serpulid tubeworms), bryozoans (Microporella sp. and Acanthodesia sp.), and vermetid gastropods (Petaloconchus intortus).     

Ichnocoenoses and taphocoenoses of posidoniid-bearing marl-limestone rhythmites and event beds,Toarcian-Aalenian,Northern Apennines,Italy

The Posidoniid-bearing rhythmic deposits, Toarcian to Aalenian (Early/Middle Jurassic) in age, of the Umbria-Marche basins (Fiuminata Colle Corno and Valdorbia type section) consist of hundred couplets, each composed by two semicouplets, a calcium carbonate-poor bed and a calcium carbonate-rich bed, respectively (CacO₃ between 10% to 85%), where event tempestite beds randomly occurs. The aim of this work is to show ichnocoenoses and taphocoenoses as well as the faunistic variations of each semicouplet and event beds. Each couplet is ∼30 cm thick in the Toarcian Rosso Ammonitico and up to 40 cm in the Aalenian Calcari e Marne a Posidonia Formation, where the sedimentation rate increased. Here, couplets were deposited in the dysaerobic/aerobic transition zone. The clay-rich portion contains abundant thin-shelled poikilaerobic bivalves and benthic foraminifers (whithout radiolarians) and shows oxygen-poor ichnocoenosis with Chondrites, while the taphocoenosis exhibits convex-upward disposition and disarticulated bivalve shells. Conversely, the limestone semicouplet is rich in radiolarians and thin-shelled bivalves, usually more burrowed (ichnocoenosis including Chondrites and few Planolites and Thalassinoides) than the former, with grouping, dispersion, biogenic fragmentation and orientation-reorientation. In all marl-limestone semicouplets, foraminifers and radiolarians exhibit a periodic inverse correlation in abundance, while thin-shelled bivalves are always abundant. Rhythmically disposed within the rhythmites are also event beds indicating an occasional oxygen-rich substrate, fine-grained calcarenitic tempestites with hummocky cross-stratification, and winnowed bed (thin shelled bivalve concentrations). These deposits are intensely bioturbated (ichnocoenosis including Skolithos, Planolites, Trypanites, Chondrites, and Thalassinoides). Taphocoenoses include fragmentation, grouping, surficial burrowing, biogenic reorientation, and deep burrowing. Ichnological and taphonomical features indicate high physical and biogenical reworking affecting sediments. The Jurassic depocenters of Valdorbia and Fiuminata that received rhythmical dilution (clay) or productivity (carbonate) cycles during Toarcian and Aalenian time can therefore strongly contribute to the study of ichnological and taphonomical variations in rhythmic conditions.     

Tithonian-Berriasian foraminiferal faunas from the Torinosu-type calcareous blocks of the southern Kanto Mountains, Japan: their implications for post-accretionary tectonics of Jurassic to Cretaceous terranes

The Torinosu-type limestones, having many lithologic characters showing their original deposition on shallow shelves, are widely distributed in the Jurassic to Cretaceous terranes of Japan. The foraminiferal faunas from the Jurassic to the lowermost Cretaceous of Japan were first revealed in the calcareous blocks of the southern Kanto Mountains. Distinguished microfaunas consist of 39 species including many marker species of the Upper Jurassic to Lower Cretaceous in Europe, West Asia, and North Africa such as Melathrokerion spirialis, Charentia evoluta, Freixialina planispiralis, Nautiloculina oolithica, Everticyclammina cf. virguliana, Haplophragmium lutzei and Pseudocyclammina lituus. These faunas suggest a Tithonian to Berriasian age of Torinosu-type limestones. They are contained in four tectonostratigraphic units (Kamiyozawa, Hikawa and Gozenyama Formations; Ogouchi Group) continuously accreted from Middle Jurassic to Late Cretaceous. The younger deposition age of Torinosu-type limestones than the accretion age (Bajocian to Bathonian) in the Kamiyozawa Formation and their older age than the accretion age of the Ogouchi Group (late Albian to middle Maastrichtian) are important to date the post-accretionary tectonics of Jurassic to Cretaceous terranes of Japan and to explain the emplacement process of Torinosu-type limestones.     

An exceptional storm accumulation of nautilids in the Lower Cretaceous of the Neuquén Basin,Argentina

Cichowolski, M., Pazos, P.J., Tunik, M.A. & Aguirre‐Urreta, M.B. 2011: An exceptional storm accumulation of nautilids in the Lower Cretaceous of the Neuquén Basin, Argentina. Lethaia, Vol. 45, pp. 121–138. An exceptional accumulation of nautilid shells of the species Cymatoceras perstriatum (Steuer) is reported and described in the Lower Cretaceous Agrio Formation of the Neuquén Basin (west‐central Argentina). The bed represents a storm deposit in a shallow‐water environment within the mid‐ramp. The evidences of a storm‐related origin of the bed come from the petrographic analysis and taphonomic features of the shells, specially the sedimentary infill pattern. The shells are dispersed in patches within the stratum, without any orientation relative to the bedding plane. It is proposed that the shells were floating after the death of the animals, although most of them have an almost complete living chamber. The presence of some heavily encrusted shells suggests that there is a mixing of specimens with different drift times. A variety of factors related to the origin of such high number of nautilid shells are discussed, including a transgressive stand system tract, the possible existence of a gregarious behaviour, changes in salinity and wind directions. □Lower Cretaceous, Nautilids, Neuquén Basin, shell accumulation, storm deposit.     

Foraminifers and algae of the late Tournaisian–early Viséan boundary interval (MFZ8–9) in the Gachal Formation (Central Iran)

Three sections of the Gachal Formation, Tang-e Vaveila, Rahdar, and Bakhshi, located in the Kalmard area near the Tabas town (Central Iran) are revised. Tang-e Vaveila is dated as latest Tournaisian (upper MFZ8) to early Viséan (upper MFZ9); Rahdar is latest Tournaisian (latest MFZ8); and Bakhshi exposes the whole early Viséan (lower and upper MFZ9) succession. The upper MFZ8 subzone is indicated by the presence of Eoparastaffellina ex gr. rotunda; the lower MFZ9 subzone by the appearance of Eoparastaffella ex gr. simplex, and the upper MFZ9 subzone by the more or less concomitant appearances of Eostaffella and Lapparentidiscus. Among the foraminiferal assemblages, the endothyroids and loeblichioids are diversified, whereas the eoparastaffellins, tournayelloids and lituotubelloids remain rare. Regionally, the tetrataxins are interesting, because five species of Tetrataxis succeed one another across the MFZ9 biozone. Rich populations of Eotextularia were also observed. Incertae sedis algae are relatively diversified with the classical moravamminales and aoujgaliales. An interesting true alga is mentioned, but left in open nomenclature, as Epimastoporeae indet. Among the other microfossils, Cryptophyllus, Hamulusella?, Draffania, and hexaphyllids are noteworthy. The new taxa are: Eoparastaffellinae n. subfam., Endolaxina paralaxa n. sp., and Vissarionovella? iranica n. sp.     

New bethylid and chrysidid wasps (Hymenoptera: Chrysidoidea) from Canadian Late Cretaceous amber

A new bethylid species, Celonophamia granama, and two new chrysidid species, Procleptes eoliami, and P. hopejohnsonae, are described from Late Cretaceous (Campanian) amber collected at the Grassy Lake locality in Alberta, Canada. Within the deposit these taxa constitute the first bethylid, and the second and third chrysidid species to be described, respectively. The new taxa expand the sparse fossil record of Chrysidoidea, particularly that of Chrysididae—a group that was previously represented by only three described species in the Mesozoic. The presence of Celonophamia species in both Canadian amber and Siberian (Taimyr) amber further emphasizes faunal similarities between these two northern Late Cretaceous amber deposits. Given the prevalence of metallic coloration in Chrysididae, the specimens described here also provide evidence for the taphonomic alteration of perceived insect colors in Cretaceous amber inclusions.     

Revision of the lower Viséan (MFZ11) calcareous algae and archaediscoid foraminifers of the Sari area (central Alborz,Iran)

The microfloral and microfaunal assemblages of the MFZ11 foraminiferal biozone (late early SomervilleViséan; formerly V2a) are well developed in the Kiyasar section of the Sari area (central Alborz; northern Iran). Regionally, this biozone MFZ11 may be subdivided into three subzones. The lower subzone, MFZ11A, is characterized by the appearances of the algae Koninckopora tenuiramosa, coeloporellacean indet. Fourstonella fusiformis, and Nanopora anglica and, among the foraminifers, by the occurrence of Ammarchaediscus bozorgniai and the disappearance of Eoparastaffella simplex; the absence of Uralodiscus rotundus, U. spp., and primitive Glomodiscus spp. in this subzone is noticeable. The next subzone, MFZ11B1, is well characterized by the appearance of Glomodiscus spp. (G. oblongus and G. cf. miloni) and the local range zone of Pararchaediscus, a genus emended herein and interpreted as a junior synonym of Archaediscus at the involutus stage and Propermodiscus; only a few characteristic issinellacean and palaeoberesellacean algae are present in this subzone. Then, the last subzone, MFZ11B2, is characterized by Hemiarchaediscus (emended herein) and Glomodiscus miloni; the upper part of this latter subzone is only marked by the apparent absence of the archaediscids and the presence of two incertae sedis algae: Crassikamaena scabrosa and Epistacheoides bozorgniai nov. sp. These assemblages indicate that at that time, Alborz remained located on the Perigondwanan southern border of the Palaeotethys, and was probably connected with the Urals as well as the northwestern branch the Palaeotethys, from Belgium to the Donets Basin.     

A new troodontid theropod dinosaur from the lower Cretaceous of Utah

Background

The theropod dinosaur family Troodontidae is known from the Upper Jurassic, Lower Cretaceous, and Upper Cretaceous of Asia and from the Upper Jurassic and Upper Cretaceous of North America. Before now no undisputed troodontids from North America have been reported from the Early Cretaceous.

Methodology/Principal Findings

Herein we describe a theropod maxilla from the Lower Cretaceous Cedar Mountain Formation of Utah and perform a phylogenetic analysis to determine its phylogenetic position. The specimen is distinctive enough to assign to a new genus and species, Geminiraptor suarezarum. Phylogenetic analysis places G. suarezarum within Troodontidae in an unresolved polytomy with Mei, Byronosaurus, Sinornithoides, Sinusonasus, and Troodon + (Saurornithoides + Zanabazar). Geminiraptor suarezarum uniquely exhibits extreme pneumatic inflation of the maxilla internal to the antorbital fossa such that the anterior maxilla has a triangular cross-section. Unlike troodontids more closely related to Troodon, G. suarezarum exhibits bony septa between the dental alveoli and a promaxillary foramen that is visible in lateral view.

Conclusions/Significance

This is the first report of a North American troodontid from the Lower Cretaceous. It therefore contributes to a fuller understanding of troodontid biogeography through time. It also adds to the known dinosaurian fauna of the Cedar Mountain Formation.     

Encrusting micro-organisms and microbial structures in Upper Jurassic limestones from the Southern Carpathians (Romania)

Late Jurassic–Early Cretaceous ?tramberk-type reef limestones are known from some parts of the Southern Carpathians in Romania. The Upper Jurassic deposits mainly consist of massif reef limestones including a variety of microbialites associated with micro-encrusters. They played an important role in the formation and evolution of the reef frameworks and thus are of significant importance for deciphering the depositional environments. For our study, the most important encrusting organisms are Crescentiella morronensis, Koskinobullina socialis, Lithocodium aggregatum, Bacinella-type structures, Radiomura cautica, Perturbatacrusta leini, Coscinophragma sp., and crust-forming coralline sponges such as Calcistella. Based on microscopic observations, microbial contribution to reef construction is documented by the abundance of dense micrite, laminate structures, clotted, thrombolithic or peloidal microfabrics, constructive micritic cortices, biogenic encrustations and cement crusts, as well as by other types of microbial structures and crusts. Most of the investigated carbonate deposits can be classified as “coral-microbial-microencruster boundstones” which are characteristic for the Intra-Tethyan domain. Their paleogeographical significance is indicated by the presence of many features comparable with carbonate deposits of rimmed platform systems from the Northern Calcareous Alps or Central Apennines. Based on the distribution of the facies and facies associations within the carbonate sequences under study we can distinguish slope and external shelf margin environments. The microbial crusts, the encrusting micro-organisms, and in some cases the syndepositional cements have stabilized and bound the carbonates of the slope facies types. Subsequently, the stable substrate favored the installation of coral-microbial bioconstruction levels.     

Late Viséan (MFZ14) foraminifers and algae from the Kirchbach Limestone (Carnic Alps,Austria) and geological implications

The Kirchbach Limestone occurs in the middle part of the early Viséan to Bashkirian Hochwipfel Formation, which was deposited in a flysch basin that formed during an extensional rifting phase in the foreland of the Noric Terrane, was filled with deep-marine synorogenic sediments and closed during the Bashkirian. The Noric Terrane split off from Gondwana and drifted towards the north, closing the flysch basin, which was part of the Paleo-Tethys. The Kirchbach Limestone is composed of bioclastic mudstone and carbonate conglomerate. Microfacies of the limestone clasts include wackestone, packstone, grainstone, and rudstone with diverse fossil assemblages. Bindstone clasts are derived from very shallow, restricted environments. Other clasts are bioclastic mudstone derived from deeper settings. All the foraminifers and algae identified correspond to the upper MFZ14 biozone, after the appearance of Bradyina; in contrast, the markers of the uppermost MFZ14 (Asteroarchaediscus, Loeblichia paraammonoides, and Warnantella) and those of MFZ15 (Janischewskina, Climacammina, and Biseriella) are totally absent. The Kirchbach markers are Cribrospira mikhailovi, Bradyina cf. flosculus, Howchinia bradyana, and Eostaffella parastruvei. Revised local taxa are Mstinia, M. minima n. comb., Consobrinellopsis n. gen., and C. ex gr. consobrina n. comb. The Kirchbach Limestone is derived from a shelf area displaying various shallow-water environments from which the clasts were transported into deeper-marine environments as sediment gravity flows. Limestone clasts of the Kirchbach Limestone indicate the presence of a shallow carbonate shelf along the northern margin of the Hochwipfel flysch basin. The late Asbian (MFZ14) limestone clasts derived from this carbonate shelf were probably subaerially exposed prior to their reworking and redeposition within the flysch sediments, which are late Brigantian (MFZ15) in age. Fossiliferous carbonate shelf sediments of Viséan–Serpukhovian (Namurian) age in the Veitsch Nappe of the eastern Graywacke Zone may be remnants of this shelf. Similar trilobite faunas of Nötsch and Veitsch indicate that they were originally adjacent and probably connected to this shelf north of the flysch basin. These data confirm that the Carnic Alps were located in the Viséan Mediterranean subprovince.     

Early Jurassic shell beds from marginal marine environments in southern Mendoza, Argentina

External estuarine facies in Late Sinemurian beds from the base of the Puesto Araya Formation in the Atuel river region, Mendoza Province, Argentina, contain concentrations of a new species of Cardinioides (a shallow burrowing suspension-feeding Pachycardiidae bivalve) and a low diversity benthic fauna. These bivalves appear in tidal inlet facies of a wave-dominated estuary (environment similar to lagoon-barrier island systems), forming bioclastic lags at the channel bases. The taphonomic attributes (such as shell articulation, degree of fragmentation and abrasion, bioclast size, orientation) change from North to South, from monospecific concentrations of nearly complete large Cardinioides shells with low degree of fragmentation and abrasion, through beds with smaller Cardinioides shells associated with a few bivalves from marine environments, to only isolated fragmented specimens associated with a fully marine biota including not only other bivalves but also brachiopods and ammonoids. This, together with different palaeoecologic, sedimentologic and stratigraphic attributes at the studied localities are evidence of southwards changing environmental conditions from marginal marine (brackish) to fully marine on the eastern margin of the Neuquén basin at that time. From detailed analysis of taphonomic features, size distribution of shells, and the associated fauna at the different localities, the new species is regarded as a brackish water endemic, possibly a low salinity euryhaline species, which inhabited well oxygenated waters. Salinity, turbulence levels and food supply were the main limiting factors in the distribution of the species.     

Dentary Morphological Variation in Clevosaurus brasiliensis (Rhynchocephalia,Clevosauridae) from the Upper Triassic of Rio Grande do Sul,Brazil

Clevosaurus was a cosmopolitan rhynchocephalian genus, known from the Late Triassic to the Early Jurassic. In South America this genus is represented by C. brasiliensis, an important component of the Linha São Luiz taphocoenosis, on the top of the Norian Santa Maria 2 Sequence of Southern Brazil. The best preserved and most abundant bone elements of C. brasiliensis are dentaries, in which variations of shape and size are observed. The aim of this study is to describe and evaluate the variation, using geometric morphometrics methods. Geometric morphometric analysis of 10 specimens highlights variations in relative size of the dentary. Most of the variation observed for PC1 (83.3%) is likely related to ontogeny, and PC2 (10.0%) is likely related to taphonomic signatures. The development patterns observed, such as the growth of the dentary, consists of differential growth in length between the posterior portion of the dentary, that grows at a higher rate, regarding the anterior portion of the element. This allometric growth is similar to what is observed in other rhynchocephalians and is accompanied by the allometric skull growth, similar to the trend exhibited by clevosaurs. The taphocoenosis is bimodal (juveniles and adults) with a bias towards adult preservation. Some diagenetic influence is reflected in deformed skulls and this is observed in the tangent-plot. Finally, a strong correlation was detected between the taphonomic signatures and the PC2, regarding specially disarticulation and degree of fragmentation.     

Nuurcala obesa sp. n. (Blattida,Caloblattinidae) from the Lower Cretaceous Yixian Formation in?Liaoning?Province,China

Nuurcala obesa sp. n., in the cockroach family Caloblattinidae, is described from the Lower Cretaceous Yixian Formation (Liaoning Province, China) based on a combination of differential characters of fore- and hind wing venation, colouration and body structures. Systematically, Nuurcala (Vršanský, 2003), known from the Cretaceous sediments of Bon Tsagaan and Khurilt, Mongolia, is closely related to other genera of Caloblattinidae known from the Jurassic and Cretaceous localities in other parts of Asia.     

Entrapment, preservation and incipient fossilization of benthic predatory molluscs within deep-water coral frames in the Mediterranean Sea

Holocene Madrepora-Lophelia subfossil frames recovered at ca. 690 m from deep-water coral grounds south of Malta (Strait of Sicily, Central Mediterranean Sea) were found to entrap shells of cnidarian predatory gastropods such as Babelomurex sentix, “Coralliophila” squamosa (morphotype ruderatus) and architectonicids. This finding documents the capability of deep-water coral reefs to serve as taphonomic traps eventually promoting the preservation of rare components of their original biota.     

Taphonomy of Eemian marine molluscs and acorn barnacles from eastern Arkhangelsk region, northern Russia

Marine Eemian deposits along the Pyoza river and its tributary Varchuska, Arkhangelsk region, constitute successions of muddy and sandy facies with rich macrobenthic fauna dominated by bivalves and barnacles. Taphonomic features formed by abrasion, disarticulation, dissolution, fragmentation, bioerosion and encrustation define taphofacies for a palaeoenvironmental model. Five bivalve taphofacies and three barnacle taphofacies could be distinguished. Both bivalves and barnacles are poorly preserved in foreshore/shoreface environments, as the shells were subjected to extensive transportation by currents. The shells were best preserved in offshore environments, where rapid episodic sedimentation enabled within-habitat preservation, in some cases even preservation in life position. Barnacles are absent from the most clay-rich offshore deposits, probably because of clogging of filters by turbidity and lack of suitable substrate. Such dissimilarities suggest that the number and distribution of taphofacies may depend on which fossil groups are used. Interspecific variability may exist within the individual taphofacies. The barnacles, for example, tend to be better preserved than the mussel Mytilus edulis, although both are fixosessile suspension feeders. This indicates that not only life habits but also intrinsic shell properties influence preservation. Thus, taphofacies analyses should combine data on taphonomic features, specific life habit and shell properties to determine overall preservation patterns. In that way, taphofacies analyses may form a powerful tool for palaeoenvironmental analyses of marine deposits.