A new fossil petalurid dragonfly (Odonata: Petaluroidea: Aktassiidae) from the Cretaceous of China

LI, Y.J., HAN, G., NEL, A. REN, D., PANG, H. & LIU. X.L., September 2012. A new fossil petalurid dragonfly (Odonata: Petaluroidea: Aktassiidae) from the Cretaceous of China. Alcheringa 36, 321–324. ISSN 0311-5518.

The new petalurid species Pseudocymatophlebia boda is described from Lower Cretaceous strata of Inner Mongolia, China. It provides additional morphological characters for this genus, which has been previously recorded from the Lower Cretaceous of England. Together with Aktassia, it is the second aktassiid genus with a very wide distribution, even though this family remains known only from Eurasia. Furthermore, a new name, Brachaktassia gen. nov., is proposed to replace the brachiopod genus Aktassia Popov, 1976.     

The distribution of the Mesozoic ostracod genus Procytherura Whatley: palaeogeographical implications with special reference to Argentina

A review is undertaken of the nine species of Procytherura known to occur in Argentina and a new species, Procytherura serangodes sp. nov. is described. The global distribution of the genus indicates that it was more or less equally diverse and widely distributed in both hemispheres during most of the Lower and Middle Jurassic, but that in the Upper Jurassic and in the Lower Cretaceous, it became progressively restricted to the Southern Hemisphere. The widespread distribution of several Jurassic species of Procytherura, which occur in both Great Britain and Northwest Europe and in Argentina, is shown to be related to the availability of important migration routes, including the Tethys and the Hispanic Corridor. In the Lower Cretaceous, the very widespread distribution of Procytherura in the Southern Hemisphere, is used to support the existence of important routes along the eastern and western seaboards of Africa, the latter associated with the opening of the South Atlantic.     

Dental caries in an Early Cretaceous ichthyosaur

A single anterior dentary tooth, recovered with a near complete juvenile ichthyosaur skull from the Early Cretaceous (upper Albian) Hughenden-Richmond region of northern Queensland, has revealed the presence of a potential dental caries (tooth decay) infection. Dental caries is a disease affecting hard dental structures including the cementum and results in cavitation. The implications of dental caries development on tooth replacement and feeding in Cretaceous ichthyosaurs are discussed.     

First record of Acesta (Bivalvia: Limidae) from the Cretaceous of Australia

The cosmopolitan, Jurassic to Recent, bivalve Acesta (Limidae) is documented from Australian Cretaceous (upper Albian) rocks in the lowermost section of the Mackunda Formation of Queensland. These specimens from Landsborough Downs, Flinders Shire, represent an endemic new species, herein named Acesta (Acesta) backae n. sp. Acesta (A.) backae n. sp. was a shallow-water suspension feeder that inhabited the Cretaceous Australian epicontinental sea of the Great Artesian Basin. Although hinge details of Acesta (A.) backae n. sp. are wanting, this new taxon is most closely allied with Acesta? sp. of the Miria Formation of Western Australia and can clearly be discriminated from other Cretaceous Austral forms.     

Late Carboniferous to Early Permian brachiopod faunas from the Bachu and Kalpin areas,Tarim Basin,NW China

Terrestrial reptile remains are very rare in the Lower Cretaceous of South Australia, but include the holotype of the small theropod Kakuru. Here, we review this taxon and other archosaur specimens collected from the Bulldog Shale (Aptian) of Andamooka and Coober Pedy. Kakuru possesses no unique characters or character state combinations and is regarded as a nomen dubium, representing an indeterminate tetanuran theropod. Two other specimens (a left metatarsal and astragalus) can be referred to Dinosauria, but the identity of several other specimens (phalanges and a centrum) can only be resolved to the level of an indeterminate archosaur.     

The record of Araucariaceae macrofossils in New Zealand

Pole, M., December, 2008. The record of Araucariaceae macrofossils in New Zealand. Alcheringa 32, 405–426. ISSN 0311-5518.

The Araucariaceae have a long record in New Zealand, extending back to the Jurassic at least, and Araucaria extends back to at least the Late Cretaceous. This paper reviews the macrofossil record of the family and presents new information based largely on the leaf cuticle record. Agathis, which is the only genus of the family currently growing in New Zealand, has no record before the Cenozoic. All specimens previously identified from pre-Cenozoic strata clearly belong to other taxa or do not show characteristic features of the genus. Araucariaceae macrofossils are virtually ubiquitous in the Cretaceous assemblages of New Zealand but are conspicuous by their absence or rarity in Palaeocene deposits. Their demise may be an expression of events at the Cretaceous–Palaeogene boundary.     

First evidence of a Late Cretaceous sea turtle from Australia

The isolated scapula of a chelonioid sea turtle is described from the Upper Cretaceous (upper Maastrichtian) Miria Formation of the Giralia Ranges in Western Australia. Character states including the wide angle of divergence between the scapular processes (possibly reaching 140°), projection of the glenoid on a constricted scapular neck, and highly vascular glenoid articular surfaces suggest affinity with dermochelyoids—the most diverse and geographically widespread clade of Mesozoic chelonioids. The Miria Formation chelonioid scapula constitutes the first definitive record of a Late Cretaceous sea turtle from Australia and is one of the few occurrences thus far documented from Upper Cretaceous–Paleogene deposits in the Southern Hemisphere.     

A new non-marine Early Cretaceous gastropod species from Lightning Ridge,New South Wales

A new species of thiarid snail attributable to the extant genus Melanoides is described from the Early Cretaceous (middle-late Albian) non-marine deposits of the Griman Creek Formation at Lightning Ridge in northern New South Wales. It represents the oldest Australian record of the genus and the family. Implications for the palaeoecology and distribution of Australian Cretaceous non-marine gastropods are discussed.     

Selachian scales from the Cenomanian (Late Cretaceous) of Bathurst Island,northern Australia

Seven selachian scale types are described from the middle Cenomanian Moonkinu Formation, outcropping on the southern shores of Bathurst Island in northern Australia. The scales are classified in accordance with previously published scale morphologies of Cretaceous and modern sharks, and are representative of the Orders Squatiniformes (Family Squatinidae), Carcharhiniformes (Family Scyliorhinidae), and Lamniformes (Family Odontaspididae). The presence of typically bottom-dwelling, shallow-water angelsharks (squatinids), catsharks (scyliorhinids), and sand tiger sharks (odontaspidids) within the Moonkinu Formation support an inner neritic depositional environment interpretation for the unit, previously determined from foraminiferal biofacies and lithology. The biostratigraphic potential of these scales can only be assessed after scales from more Cretaceous localities are described and documented.     

NUCLEAR MAGNETIC RESONANCE CHARACTERIZATION OF CRETACEOUS AMBER

Carbon-13 nuclear magnetic resonance spectra have been examined under high resolution conditions for 31 samples of fossil resin that have been dated to the Cretaceous period. Samples from Alaska, Canada, parts of the United States, Greenland, France, Switzerland, Lebanon, Jordan, and Israel have very similar spectra, consistent with a common, geographically dispersed palaeobotanical source. Samples within this large group exhibit a variation in spectral linewidth that is consistent with differences in sample age or maturity. A single Triassic sample from Bavaria shows the same spectral patterns but greater linewidths, indicating that it probably had a similar palaeobotanical source.     

CROSS‐CHANNEL CONNECTIVITY: WEALDEN WHETSTONE IMPORTS FROM ROMAN BRITAIN TO THE CONTINENT

The purpose of this paper is to demonstrate cross‐Channel exchange of calcareous sandstone‐type whetstones derived from the Weald (Sussex, UK) in the Roman period. The presence of this particular type of whetstone at several Roman sites on the Continent – more specifically, in Belgium, France and the Netherlands – is reported for the first time. The morphology, geological provenance, petrographic characteristics and distribution patterns are discussed, based on a comparative analysis with archaeological and geological reference material. The geological analysis identifies a common geological source for the Continental finds: the very fine‐grained, thin‐bedded, flagstone‐like calcareous sandstone beds of the Lower Cretaceous Wealden Clay Formation. These sandstones were, most probably, extracted in the north‐western part of the Weald area. The distribution pattern of the archaeological material implies the importance of personal mobility, with potential military affinities.     

The origin of overpressure in 'old' sedimentary basins: an example from the Cooper Basin, Australia

Overpressure in ‘old’ sedimentary basins that have not undergone rapid, recent sedimentation cannot be easily explained using traditional burial‐driven mechanisms. The last significant burial event in the Cooper Basin, Australia, was the Late Cretaceous deposition of the Winton Formation (98.5–90 Ma). Maximum temperature in the basin was attained during the Late Cretaceous, with cooling beginning prior to 75 Ma. Hence, overpressure related to rapid burial or palaeomaximum temperatures (e.g. hydrocarbon generation) must have developed prior to 75 Ma. Retaining overpressure for 75 Ma in ‘old’ basins such as the Cooper Basin requires extremely low seal permeabilities. An alternative explanation is that overpressure in the Cooper Basin has been generated because of an increase in mean stress associated with an increase in horizontal compressive stress since Late Cretaceous times. Structural observations and contemporary stress data indicate that there has been an increase in mean stress of approximately 50 MPa between Late Cretaceous times to that presently measured at 3780 m. The largest measured overpressure in the Cooper Basin is 14.5 MPa at 3780 m in the Kirby 1 well. Hence, disequilibrium compaction driven by increasing mean stress can explain the magnitude of the observed overpressure in the Cooper Basin. Increases in mean stress (tectonic loading) may be a feasible mechanism for overpressure generation in other ‘old’ basins that have undergone a recent increase in horizontal stress (e.g. Anadarko Basin).     

Petrology and Geochemistry of Late Intermediate Period Ceramics,Southern Peru

Multiple petrological and geochemical analytical techniques revealed significant similarities in element and mineral distribution between the 47 ceramic samples from Chillo (southern coast, Peru), a Late Intermediate Period (ad 1000–1400) archaeological site. The similarity indicates a common raw material source. The analytical results of Holocene fluvial sediment samples, Cretaceous clay layers and fired and non‐fired bricks, only eliminated the Cretaceous clay layers as a potential source material. Applying Raman spectroscopy, the red and violet colour of the slip is due to hematite, the yellow colour to a mixture of hematite, graphite and gypsum, and the black colour is either graphite or jacobsite.     

Secular variations in seawater chemistry as a control on the chemistry of basinal brines: test of the hypothesis

The hypothesis that basinal brines inherited their major ion chemistries and elevated salinities from evaporated paleoseawaters is tested by comparing the compositions of basinal brines in Silurian (Michigan basin, Illinois basin, Appalachian basin in eastern Ohio) and Jurassic/Cretaceous (Central Mississippi Salt Dome basin, Arkansas shelf, and south‐central Texas) host rocks, when the world oceans were ‘CaCl₂ seas’, with those from Permian and Pennsylvanian rocks (Palo Duro basin, Central Basin Platform, and Delaware basin, Texas and New Mexico) when the world oceans were ‘MgSO₄ seas’. Basinal brines examined are assumed to have originally formed from evaporation of the same seawaters that produced major evaporites. Sulfate, Mg and K levels in basinal brines are below the concentrations expected from evaporation of seawater of any type, which emphasizes the importance of diagenetic mineral–brine interactions in controlling basinal brine chemistry. There are no major differences in SO₄, Mg and K concentrations between basinal brines hosted by rocks originally formed during ages when the world oceans were MgSO₄ seas versus CaCl₂ seas. Basinal brines in Pennsylvanian–Permian rocks are compositionally distinct (relatively high Na and low Ca) from basinal brines in Silurian, Jurassic and Cretaceous host rocks, which may reflect original differences in seawater chemistry. Basinal brines enriched in Ca and depleted in Na relative to evaporated seawater of any type have traditionally been interpreted to form by albitization of plagioclase feldspar. A new explanation for Ca enrichment and Na depletion of basinal brines is the mixing of evaporated CaCl₂‐type seawater with more dilute water. Some basinal brines are similar in major ion composition to evaporated seawater of a particular age, for example basinal brines in the Cretaceous Edwards Group carbonates, Texas, where dolomitization is the only reaction required to convert evaporated Mesozoic CaCl₂ seawater into Edwards Group brine.     

New species of Late Jurassic Australobuchia (Bivalvia) from the Murihiku Terrane,Port Waikato—Kawhia region,New Zealand

The Early Cretaceous Otway and Strzelecki Groups exposed on the southern coast of Victoria, Australia, have produced a fauna of dinosaurs that lived within the Antarctic Circle. As many as five or six species of hypsilophodontids numerically dominate the collections from there, but the rarer and more fragmentary theropod remains suggest a surprising diversity of carnivorous dinosaurs. A possible surangular and an isolated vertebra have characters considered diagnostic for Late Cretaceous oviraptorosaurs of the Northern Hemisphere. Other fossils suggest the presence of ornithomimosaurs, dromaeosaurids and neoceratopsians, and with the possible oviraptorosaur remains, challenge the widespread assumption that these animals originated on the northern continents.     

A possible succineid land snail from the Lower Cretaceous non-marine deposits of the Griman Creek Formation at Lightning Ridge,New South Wales

A diverse non-marine molluscan fauna has been recorded from the Lower Cretaceous (middle–upper Albian), low-energy, fluvial sediments of the Griman Creek Formation at Lightning Ridge in northern New South Wales. We describe a novel addition to this assemblage—a probable pulmonate gastropod that manifests features (including shell with an inflated body whorl, expansive aperture, and reduced spire/whorl count) consistent with Succineidae, an extant cosmopolitan family of terrestrial snails. The fossils are assigned to a new genus and species (Suratia marilynae), distinguishable from existing taxa by a combination of traits: shell with sculpturing limited to fine growth lines only, lunate body whorl with a rounded periphery, markedly flattened spire (comprising up to two whorls), which is almost flush with the apical surface and delineated by a deeply impressed sutural ‘gutter,’ and presence of both a broad columellar plait and distinct columellar fold. The new taxon apparently constitutes the oldest pulmonate remains recorded from Australasia, and extends the known stratigraphical range of succineids back to the Lower Cretaceous in the Southern Hemisphere.     

Syntectonic infiltration by meteoric waters along the Sevier thrust front,southwest Montana

Structural, petrographic, and isotopic data for calcite veins and carbonate host‐rocks from the Sevier thrust front of SW Montana record syntectonic infiltration by H₂O‐rich fluids with meteoric oxygen isotope compositions. Multiple generations of calcite veins record protracted fluid flow associated with regional Cretaceous contraction and subsequent Eocene extension. Vein mineralization occurred during single and multiple mineralization events, at times under elevated fluid pressures. Low salinity (T_m = ?0.6°C to +3.6°C, as NaCl equivalent salinities) and low temperature (estimated 50–80°C for Cretaceous veins, 60–80°C for Eocene veins) fluids interacted with wall‐rock carbonates at shallow depths (3–4 km in the Cretaceous, 2–3 km in the Eocene) during deformation. Shear and extensional veins of all ages show significant intra‐ and inter‐vein variation in δ¹⁸O and δ¹³C. Carbonate host‐rocks have a mean δ¹⁸O_V‐SMOW value of +22.2 ± 3‰ (1σ), and both the Cretaceous veins and Eocene veins have δ¹⁸O ranging from values similar to those of the host‐rocks to as low as +5 to +6‰. The variation in vein δ¹³C_V‐PDB of ?1 to approximately +6‰ is attributed to original stratigraphic variation and C isotope exchange with hydrocarbons. Using the estimated temperature ranges for vein formation, fluid (as H₂O) δ¹⁸O calculated from Cretaceous vein compositions for the Tendoy and Four Eyes Canyon thrust sheets are ?18.5 to ?12.5‰. For the Eocene veins within the Four Eyes Canyon thrust sheet, calculated H₂O δ¹⁸O values are ?16.3 to ?13.5‰. Fluid–rock exchange was localized along fractures and was likely coincident with hydrocarbon migration. Paleotemperature determinations and stable isotope data for veins are consistent with the infiltration of the foreland thrust sheets by meteoric waters, throughout both Sevier orogenesis and subsequent orogenic collapse. The cessation of the Sevier orogeny was coincident with an evolving paleogeographic landscape associated with the retreat of the Western Interior Seaway and the emergence of the thrust front and foreland basin. Meteoric waters penetrated the foreland carbonate thrust sheets of the Sevier orogeny utilizing an evolving mesoscopic fracture network, which was kinematically related to regional thrust structures. The uncertainty in the temperature estimates for the Cretaceous and Eocene vein formation prevents a more detailed assessment of the temporal evolution in meteoric water δ¹⁸O related to changing paleogeography. Meteoric water‐influenced δ¹⁸O values calculated here for Cretaceous to Eocene vein‐forming fluids are similar to those previously proposed for surface waters in the Eocene, and those observed for modern‐day precipitation, in this part of the Idaho‐Montana thrust belt.     

A new Maastrichtian-Paleocene Azolla species from of Bolivia,with a comparison of the global record of coeval Azolla microfossils

A new heterosporous fern species, Azolla boliviensis sp. nov., is described from latest Maastrichtian (latest Cretaceous) to Paleocene (earliest Palaeogene) terrestrial sediments of the Eslabón and Flora Formations, Subandean belt, Bolivia. The species is represented by dissociated but abundantly co-preserved megasporocarps, megaspores, microsporangia, massulae and microspores. The genus consistently characterizes warm-climate lacustrine settings. Fossil Azolla is first identified around the Early to mid-Cretaceous but the genus apparently underwent dramatic radiation during the Late Cretaceous. Abundant Azolla remains in Bolivia add to this portrait of rapid geographie dispersai and diversification near the close of the Cretaceous. The ranges of many Azolla species span the Cretaceous- Palaeogene boundary and the potential of Azolla to withstand altered environmental conditions, such as periodic frost damage, drought, and salinity change, and its ability to undergo rapid vegetative regeneration in association with nitrogen-fixing cyanobacterial symbionts, suggest that the survival of this group was favoured during the adverse conditions of the end-Cretaceous event.     

Confirmation of a Middle Jurassic age for the Eedemt Formation in Dundgobi Province,southeast Mongolia: constraints from the discovery of new spinicaudatans (clam shrimps)

Two spinicaudatan species, Triglypta eedemtensis Li sp. nov. and Dundgobiestheria mandalgobiensis Li gen. et sp. nov., are described on the basis of scanning electron microscopy (SEM) imaging of newly collected specimens from paper-thin laminated black shale of the Eedemt Formation exposed at the Eedemt locality in the Khootiin Khotgor coal mine region of Dundgobi Province in southeast Mongolia. Triglypta eedemtensis is ornamented mainly with puncta and a punctate fine reticulum; radial lirae occur only on two or three growth bands near the venter. The small spinicaudatan Triglypta is a common component of the Middle Jurassic Euestheria ziliujingensis fauna and Sinokontikia fauna, and is a typical taxon in the Middle Jurassic lacustrine sequences of northern Hebei and the Junggar and Turpan basins of the Xinjiang Autonomous District of China; however, it does not occur in stratigraphically higher units elsewhere. Therefore, the age of the Eedemt Formation should be considered Middle Jurassic rather than Early Cretaceous. The Eedemt Formation is much older than the Early Cretaceous Shinekhudag Formation in the Shine Khudag area of southeast Mongolia.     

Metaceratodus kaopen comb. nov. and M. wichmanni comb. nov., two Late Cretaceous South American species of an austral lungfish genus (Dipnoi)

Cione, A.L. & Gouiric-Cavalli, S., June 2012. Metaceratodus kaopen comb. nov. and M. wichmanni comb. nov., two Late Cretaceous South American species of an austral lungfish genus (Dipnoi). Alcheringa 36, 203–216. ISSN 0311-5518.

Metaceratodus wollastoni, an Australian species, was reported from Upper Cretaceous beds of Patagonia in 1997. Later, three new species (Ceratodus wichmanni, Ptychoceratodus kaopen and Ptychoceratodus cionei), based on scarce material, were described from the same region. Two of these species were later referred to Ferganoceratodus. After examining much more abundant and better-preserved material, we conclude that neither the occurrence of Metaceratodus wollastoni nor those of Ptychoceratodus and Ferganoceratodus in the Cretaceous of South America are supported. We consider that C. wichmanni and P. cionei are synonyms and we reassign the three putative species to Metaceratodus under two new combinations: M. kaopen comb. nov. and M. wichmanni comb. nov. Both differ from the other species of the genus in having pits over most of the occlusal surface and a different occlusal profile of the tooth plate, and most have four ridges in the lower and upper tooth plates. Metaceratodus wichmanni differs from M. kaopen in oclussal profile, inner angle, and symphysis development among other features. Metaceratodus kaopen is known from the upper Santonian–lower Campanian Anacleto Formation of Río Negro province and M. wichmanni from upper Campanian–lower Maastrichtian units of Chubut, Río Negro, Neuquén and Mendoza provinces, Argentina. The occurrence of Metaceratodus in southern South America corroborates a close biogeographical relationship with Australia in the latest Cretaceous.

Alberto Luis Cione [acione@museo.fcnym.unlp.edu.ar] and Soledad Gouiric-Cavalli [sgouiric@museo.fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n, W1900FWA La Plata, Argentina. Received 23.11.2010, revised 11.7.2011, accepted 7.8.2011.