Cherts and silicified dolostones of the ca. 1600 Ma Dahongyu Formation (uppermost Changcheng Group) from North China contain well-preserved microfossils. Cyanobacteria filaments and coccoids dominate the studied Dahongyu microbiota in the Jixian section. These microfossils show the characteristics of endobenthic, epibenthic, and allochthonous microfossils, which illustrated well a vertical distributional view of an intertidal microbiota. Large numbers and size of allochthonous microfossils are the distinguishing characteristics of this new microbiota. A few of these possess ornaments or odd morphology, which suggest their potential eukaryotic nature. Through regional comparisons, it is revealed that there was significant regional disparity within the Yanshan Basin of microbiotas during deposition of the Dahongyu Formation. The newly studied Dahongyu microbiota is similar to the microbiota from the underlying Changcheng Group, with only slight differences. The absence of typical eukaryotes and the emergence of unique microfossils (especially small fusiform microfossils) make the Dahongyu Formation and the subsequent strata of the Jixian Group distinct from contemporaneous eukaryote-bearing strata.

In the Dahongyu assemblage, 19 species were recognized, six species were identified informally and seven species were identified in open nomenclature. One new taxon of microfossil was described: Xiaohongyuia sinica Shi and Feng new genus new species.

Vase-shaped microfossils (VSMs) occur in dolomitic extraclasts of indeterminate provenance within the basal diamictite of the Neoproterozoic Urucum Formation (Jacadigo Group) of west-central Brazil, having an age constrained between 889±44 Ma (K-Ar; basement rocks) and 587±7 Ma (40Ar/39Ar age of early metamorphic cryptomelane in overlying manganese ore). Early isopachous carbonate cement entombed these VSMs, preserving rare direct evidence of original wall composition that is carbonaceous (now kerogenous) in practically all specimens. Some tests are siliceous or composed of a quartz-kerogen mixture; secondary replacement explains some features of these tests, but original biomineralization seems more likely for others. This interpretation, coupled with test morphology, suggests affinity to arcellinid testate amoebae. Five VSM taxa are recognized in the deposit: Cycliocyrillium simplex Porter, Meisterfeld, and Knoll, 2003, and C. torquata Porter, Meisterfeld, and Knoll, 2003, originally described in the Chuar Group (USA), and three new monospecific genera—Palaeoamphora urucumense n. gen. n. sp., Limeta lageniformis n. gen. n. sp., and Taruma rata n. gen. n. sp. Most of the taxonomically important characteristics of these VSMs occur also in extant testate amoebae, but the combinations of some characters, such as organic-walled tests having exceptionally long necks that exhibit terminal apertures (L. lageniformis n. gen. n. sp.), are evidently novel additions to the known diversity of Neoproterozoic VSMs. Evidence of glacially influenced deposition in the conformably overlying Santa Cruz Formation may indicate that the Urucum Formation slightly preceded or was penecontemporaneous with a major Neoproterozoic glaciation, although the VSM-hosting extraclasts must be older, possibly rivaling the age of the testate amoebae of the Chichkan Formation (766±7 Ma) that are currently regarded as the oldest record of protists in the geological record.

A new genus of flabellid scleractinian coral, Periplacotrochus, is described from the late Eocene to middle Miocene of Victoria, South Australia, and Tasmania. It differs from Placotrochus in having a pedicellate base, and from Flabellum in having a lamellar columella. Six previously described species are redescribed, illustrated, and reassigned to this genus (P. deltoideus Duncan, 1864, P. corniculatus Dennant, 1899, P. elongatus Duncan, 1864, P. pueblensis Dennant, 1903, P. inflectus Dennant, 1903, and P. magnus Dennant, 1904), and one new species is described: P. cudmorei. One species, Placotrochus elegans Tennison-Woods, 1878a, is considered as a nomen dubium. A key is provided to the seven species placed in this genus.

Devonian bactritids are described for the first time from South America. They come from siliciclastic rocks of the Talacasto Formation in the Precordillera Basin, west-central Argentina. The host strata span the Lochkovian–Emsian and contain other non-ammonoid cephalopods as well, thus refuting the alleged virtual absence of cephalopods in circumpolar Devonian basins from southwestern Gondwana (the Malvinokaffric Realm). We report Bactrites gracilis and Devonobactrites? sp., whose wide distribution contrasts with the endemic paleobiogeographic signature of some other taxonomic groups in these basins. Furthermore, new Lochkovian and Pragian records of Bactrites sp. provide new insights into the earliest bactritid records worldwide.

The nuculanid bivalve Costinuculana magharensis new genus new species is described from the middle to upper Bathonian Kehailia Formation of Gebel Maghara, North Sinai, Egypt. Costinuculana differs from other genera of the family Nuculanidae by the presence of opisthocline ribs along the rostrum. These ribs are variable in shape and size, straight to folded posteriorly, bifurcate ventrally and occasionally postero-dorsally, and cover an area ~45% of the total valve length from the posterior end. The life position of C. magharensis n. gen. n. sp. is reconstructed on the basis of a functional interpretation of its morphology and by comparison with closely related Recent forms. The asymmetrical commarginal ribs facilitated the burrowing process. The posterior oblique ribs are asymmetrical in cross-section with a steeply concave side in the burrowing direction and slightly convex side in the opposite direction. They probably kept the bivalve in a stable position once the desired depth had been reached. The thick oblique ribs probably also increased the strength of the rostrum and offered resistance against durophagous predators, being presumably partly exposed above the sediment-water interface. Based on the associated fauna, Costinuculana n. gen. lived in a low-energy environment characterized by a fine-grained, soft substrate.

Eleven species of chemosymbiotic bivalves are reported from middle to late Miocene methane seep deposits (‘Calcari a Lucina’) in the Italian Apennines, including seven new species and one new genus. The new species are Bathymodiolus (s.l.) moroniae and B. (s.l.) miomediterraneus among the Bathymodiolinae and Archivesica aharoni, A. apenninica, A. strigarum, and ‘Pliocardia’ italica among the Vesicomyidae; specimens from the middle Miocene of Deruta are reported as Archivesica aff. aharoni. Samiolus iohannesbaptistae new genus new species is introduced for an unusual mytilid with a commarginally ribbed surface, which might be the first non-bathymodiolin mytilid obligate to the seep environment. The two large lucinid species from which these deposits derived their informal name ‘Calcari a Lucina’ are identified as Meganodontia hoernea (Des Moulins, 1868) and Lucinoma perusina (Sacco, 1901). With Chanellaxinus sp., we report the first thyasirid from a Neogene deep-water seep deposit in Italy and the first fossil occurrence of this genus.

A new spinicaudatan species, Estherites? jocelynae new species, is described from more than fiftyspecimens collected from the Medicine Lodge Formation (early Oligocene) of the Beaverhead Basin in southwestern Montana, USA. This is the first spinicaudatan species reported from Cenozoic strata of North America and is the second-youngest fossil clam shrimp described globally. The new species extends the range of the superfamily Estheriteoidea into the Paleogene. Carapaces of E.? jocelynae n. sp. are preserved as a calcium carbonate replacement of the original chitin-calcium-phosphate structure, which is an uncommon style of preservation for spinicaudatans. The unique preservation coupled with the range extension suggests that the sparse Cenozoic fossil record of spinicaudatans may be partly attributable to preservation bias related to geochemical conditions rather than exclusively to diversity decline following the end-Cretaceous mass extinction. The presence of E.? jocelynae n. sp. in the Medicine Lodge Formation indicates that lakes in the Beaverhead Basin experienced seasonality and fluctuating lake levels with at least some drying at the lake margins. The ecological inferences support previous paleoenvironmental interpretations based on paleobotanical and other faunal evidence.

Systematic paleontology of three new species of Petalocrinidae (Crinoidea) are documented from the carbonate-dominated units of the Shihniulan and equivalent Leijiatun formations (Llandovery, Silurian) of the Baisha, Fengxiang, and Shuibatang sections in Guizhou (China). New taxa are from the Upper Yangtze Epicontinental Sea of the South China Block. The new taxa include Petalocrinus stenopetalus new species, Spirocrinus circularis new species, and S. dextrosus new species. They have a narrow spatial and temporal (Aeronian) distribution. Evolutionary patterns of the four genera of Petalocrinidae are outlined based on the specialized characters of the fused arm plates. Phylogenetic analysis was used to assess morphological relationships within the Petalocrinidae. Petalocrinus inferior represents the plesiomorphic condition for the group and nests as a sister group of P. stenopetalus n. sp. and the Spirocrinus species used in this analysis and the clade exclusively comprised of Sinopetalocrinus. The phylogenetic analysis suggests that Petalocrinus, as currently defined, might be a paraphyletic genus.

Considerable numbers of exceptionally preserved conodont apparatuses with hyaline elements are present in the middle-upper Darriwilian (Middle Ordovician, Whiterockian) Winneshiek Konservat-Lagerstätte in northeastern Iowa. These fossils, which are associated with a restricted biota including other conodonts, occur in fine-grained clastic sediments deposited in a meteorite impact crater. Among these conodont apparatuses, the common ones are identified as Archeognathus primus Cullison, 1938 and Iowagnathus grandis new genus new species. The 6-element apparatus of A. primus comprises two pairs of archeognathiform (P) and one pair of coleodiform (S) elements. The 15-element apparatus of I. grandis n. gen. n. sp. is somewhat reminiscent of the prioniodinid type and contains ramiform elements of alate (one element) and digyrate, bipennate, or tertiopedate types (7 pairs). Both conodont taxa are characterized by giant elements and the preservation of both crowns and basal bodies, the latter not previously reported in Ordovician conodont apparatuses. Comparison of the apparatus size in the Winneshiek specimens with that of the Scottish Carboniferous soft-part-preserved conodont animals suggests that the Iowa animals were significantly larger than the latter. The apparatus of A. primus differs conspicuously from the apparatuses of the prioniodontid Promissum from the Upper Ordovician Soom Shale of South Africa although the apparatus architecture of I. grandis n. gen. n. sp. shows some similarity to it. Based on the Winneshiek collections, a new family Iowagnathidae in Conodonta is proposed.

This newly described chondrichthyan fauna from the late Miocene Chucunaque Formation of Lago Bayano reveals a prolific and highly diverse assemblage from Panama, and one of the richest shark faunas from the Neotropics. Strontium geochronology indicates an age of 10–9.5 Ma for the chonrichthyan-bearing strata. Field efforts resulted in 1429 identifiable specimens comprising at least 31 taxa, of which at least eight are new to the documented fossil record of Panama. With this information an analysis of functional diversity was conducted, indicating ecosystems dominated by generalist species feeding upon a wide range of organisms, from plankton to marine mammals. A probabilistic approach of paleobathymetric estimation suggests a neritic environment. Previous studies based on foraminifera have suggested that the Chucunaque Formation had a greater Pacific Ocean affinity, making this the first Miocene chondrichthyan fauna described from the Pacific shelf of Panama. However, our geographic comparisons show that this fauna has mixed Caribbean and Pacific biogeographic affinities, which likely supports the previously purported connection between chondrichthyan faunas during the late Miocene.

We report the first occurrence of an actinopterygian fish from the Lower Jurassic Navajo Sandstone, discovered in the Grand Staircase-Escalante National Monument in southern Utah, U.S.A. The site contains multiple individuals, preserved within an interdune deposit, possessing the elongate modified dorsal scales usually characterizing semionotiform fishes. The presence of moderately sized fish provides further evidence that interdune oases were occasionally persistent environmental habitats within the greater Navajo dune system, and that the paleobiota is still woefully undersampled. Additionally, this site could help fill a gap in the actinopterygian fossil record between the patchy Lower Jurassic and better-known Middle Jurassic documentation of western North America.

Priacanthids are a small family of percomorph fishes comprising fewer than 20 extant species currently assigned to four genera. One of these, Pristigenys, was established by Louis Agassiz (1835) to include the Eocene species Pristigenys substriata from Monte Bolca, and is usually regarded as a subjective senior synonym of Pseudopriacanthus. Consequently, Pristigenys currently comprises five extant species plus the fossil Pristigenys substriata. The osteology of the type species of this genus, however, is poorly known, and this makes it difficult to provide an adequate comprehensive definition of the taxonomy of the whole family. Pristigenys substriata is redescribed in detail based on five well-preserved articulated skeletons. Pristigenys substriata can be easily distinguished from other priacanthids based on its unique combination of characters. Morphological analysis of the fossil specimens reveals that there is substantial evidence to justify recognition of both Pristigenys and Pseudopriacanthus as valid genera, with extant species previously assigned to Pristigenys now referred to Pseudopriacanthus. Within the Priacanthidae, Pristigenys and Pseudopriacanthus form sister taxa and this pair can be considered as the sister-group to all remaining extant priacanthid genera (Cookeolus + [Heteropriacanthus+Priacanthus]).

A new species of toxodontid notoungulate, Xotodon maimarensis n. sp., is described from the Maimará Formation (late Miocene–early Pliocene), Jujuy Province, northwestern Argentina. This is the first record of a toxodontid from the Eastern Cordillera. The specimen is housed at the Museo de Geología, Mineralogía y Paleontología, Instituto de Geología y Minería de la Universidad Nacional de Jujuy. It consists of an incomplete mandible preserving the right mandibular ramus with part of the dental series, partially preserved symphysis with all the incisors, and a small portion of the left ramus without teeth. The following characters distinguish it as a new taxon: symphysis long and narrow with slight divergence of its lateral borders; strong procumbence of lower incisors and deeply implanted i3; chin angle lower than in X. major and X. cristatus and bulging labial keel limiting strong lateral concavities. Comparative analysis in the context of the recently revised Neogene Toxodontidae indicates that the Maimará specimen shares mandibular features and dental characters with Xotodon and Mixotoxodon, differing from the latter by the more upraised symphysis. The phylogenetic position of Xotodon maimarensis n. sp. supports the taxonomic interpretation of the studied specimen as a new species of Xotodon. This new Toxodontidae increases the knowledge of the diversity and radiation of this group of notoungulates in northwest Argentina.