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Eleven concretions containing the nephropid lobster, Palaeonephrops browni (Whitfield, 1907), from the Upper Cretaceous (Campanian), Bearpaw Formation in northeastern Montana, were examined using visual and geochemical methods. The concretions were zoned, with an axial, phosphate-rich core also containing calcium surrounding the lobster remains and an outer, calcium-rich zone lacking phosphate. The overall composition documents these as carbonate concretions, not phosphatic concretions. Where visible, the inner zone is sheathed in a thin layer dominated by framboidal pyrite, suggesting formation by a microbial film. The different geochemical settings in the inner versus outer zones suggest reduced pH conditions during formation of the inner core and normal pH conditions resulting in formation of the outer zone. The pattern is suggestive of extremely rapid preservation of the lobster remains within a microbial sheath in which a calcium phosphate mineral, probably francolite, delicately replaced the lobster cuticle, and traces of worm (?) burrows and fecal pellets were preserved. The remainder of the concretion, the outer zone, formed under normal pH conditions and was probably induced by the chemistry of the core. Size of the concretions relative to the size of the enclosed lobsters, lack of evidence of a burrow complex in the surrounding sediment, and central positioning of the lobster remains within the concretions do not support the contention that the lobsters were entombed within a burrow.
An assemblage of large-diameter vertical burrows interpreted as lungfish estivation burrows is documented from the Upper Cretaceous (Maastrichtian) Maevarano Formation of northwestern Madagascar. These burrows suggest that lungfish were present in the Maevarano Formation paleofauna, and they are the first lungfish estivation burrows described from the rock record of Gondwana. Over 100 large-diameter burrows penetrate a pervasively cross-stratified fluvial sandstone body intercalated near the top of the Masorobe Member. The surface of this sandstone body was mapped and 74 burrows were documented in an area spanning ∼110 m2. Burrows cut through and deform surrounding foreset laminae, and in some cases impact surrounding strata up to 8 cm from the edges of individual burrows. In map view, the burrows exhibit three distinctive morphologies: circular, elliptical, and figure-eight shaped. These three map view cross sections are very similar to the modern burrow morphology of the African lungfish Protopterus when its burrow is exhumed along its full vertical expanse. Combined, these transverse-section views provide indication of lungfish estivation, and they are supplemented by several additional key characteristics, including spatial clustering (reflecting gregarious behavior), possible fin traces, and oxidized burrow margins. The localized occurrence of 100 lungfish estivation burrows is consistent with previous reconstructions that posit a dryland paleoenvironment with a markedly seasonal wet-dry climate for the Maevarano Formation.
Numerous coprolites have been found in the Vyazniki and Gorokhovets localities of European Russia. Five identified coprolite-bearing horizons occur in the upper Permian deposits of the Vyatkian Regional Stage. Coprolites were collected from mudstone with a coprolite breccia-like layer and also from intraformational conglomerates that were deposited in a floodplain and overbank environment. Two coprolite morphotypes (A and B) are recognized from size and shape analysis of 32 specimens. Morphotype A has long, nonsegmented feces. Smaller, cylindrical or tubular-shaped coprolites of morphotype B are commonly segmented. SEM images of the coprolite matrix show spheres and thin-walled vesicles with diameters 0.5–4 µm. Electron Micro Probe (EMP) analyses of polished thin sections show microcrystalline carbonate-fluoride-bearing calcium phosphate with small amounts of calcium replaced in the crystal lattice. Optical microscopy and EMP investigations show that iron and manganese oxides are responsible for elevated iron and manganese concentrations in the bulk mass of coprolites. Other metals (V, Ni) can be associated with oxides forming spheroids with diameters 3–10 µm. REEs (rare earth elements, U, and other trace element concentrations suggest significant eolian sediment input to the burial environment of the coprolites. The scats contain fish scales and bones of tetrapods (amphibians or reptiles). In one large-sized coprolite, a small fragment of therapsid bone was also found. Both morphotypes are matched to carnivorous taxa within the Archosaurus rossicus zone of the Eastern Europe. The size and shape of the best-preserved specimens suggest that they were possibly produced by a large therapsid, anthracosaur, or early archosauromorph predator.
Abundant calcareous tubeworms have been found in both shallow platform and deep basin deposits after the end-Permian mass extinction in the Cili area, South China. Tubeworms from the microbialites deposited on the shallow platform appear to be cone-shaped tubes with diameters ranging from 0.5 to 1.8 mm (mean 1.1 mm), while those attached to Claraia, the most abundant bivalve fossil preserved in the deep basin deposits after the mass extinction, are planispiral tubes with smaller diameters (0.5–1.5 mm, mean 0.9 mm). The calcareous tubeworms are identified as Microconchida (Tentaculita) according to the typical laminated sheet texture of the tubeworms found on the shallow platform. The difference in morphology between the cone-shaped tubeworms found in the microbialites and the planispiral tubeworms attached to Claraia in deeper water deposits may be related to differences in how fast the surrounding sediments were accumulating. Bacterially mediated precipitation of calcium carbonate led to rapid accumulation of the microbialites that forced the tubeworms to grow upward so as to keep up with the rate of microbialite growth and led to the cone-shaped tubes found there, whereas the slowly accumulating sediments surrounding the tubeworm-encrusted Claraia led to the development of the planispiral forms in basin deposits. Calcareous tubeworms found in the shallow platform and colonizing the shells of bivalve Claraia in basin deposits indicates calcareous tubeworms, as a significant disaster form, should have benefited from the opening of ecological space by the extinction of most marine invertebrates. Widespread oceanic anoxia has long been considered to be one of the extraordinary conditions after the end-Permian mass extinction. Tubeworm fossils flourishing in basin deposits within the short interval near the Permian-Triassic boundary implies that the deepwater environment immediately after the end-Permian mass extinction may not have been as anoxic as previously thought.
We analyze 35 Eocene and Neogene floras from Europe (fruits, leaves, and pollen of woody taxa) to trace fruit dispersal syndromes in the fossil record. These derive from vegetation units spanning paratropical broad-leaved evergreen, mixed mesophytic, broad-leaved evergreen, and broad-leaved deciduous forests. The dispersal syndromes distinguished are fleshy and nonfleshy zoochorous, anemochorous, autochorous, and hydrochorous. Additionally, zonal and azonal taxa were distinguished to test whether the dispersal syndromes are equally distributed reflected in the zonal and azonal record. The results show very similar proportions of dispersal modes in the fossil record compared to modern forests. This suggests a consistent relationship in the Northern Hemisphere between vegetation type and dispersal spectrum in the last 50 million years. Paratropical forests show the highest values of fleshy zoochorous taxa and the lowest of anemochorous taxa. Fleshy zoochorous proportions remain high in broad-leaved evergreen forests. They are lower in subhumid sclerophyllous and lowest in broad-leaved deciduous forests. For anemochorous taxa this trend is inverted: lowest values derive from paratropical forests and highest from subhumid sclerophyllous and broad-leaved deciduous forests. Nonfleshy zoochorous taxa always show relatively low percentages but their values are somewhat higher in subhumid sclerophyllous and broad-leaved deciduous forests than in broad-leaved evergreen forests. Autochorous and hydrochorous dispersal modes are always very low. Whether in the Eocene or Neogene, the azonal record always has a higher anemochorous fraction. Because climate change instigates vegetational change, our findings link climate to changing resources for smaller vertebrates, although the consistent availability of nonfleshy zoochorous fruits since the late Eocene suggests a consistent resource, especially for rodents.