A new upper Bajocian ammonite assemblage containing the morphoceratids Dimorphinites dimorphus (d'Orbigny) and Vigoriceras defrancei (d'Orbigny) is reported from the circum-Pacific area. These ammonites were found at the top of the Torcazas Formation, in the Quebrada San Pedro area, Precordillera of northern Chile. Taphonomic, systematic, and paleobiogeographic data confirm these dimorphs were part of indigenous populations within the Tarapaca Basin, belonging to the same demic biospecies: Dimorphinites defrancei (d'Orbigny). The West Tethyan and East-Pacific distribution of D. defrancei corroborates the availability of the migratory seaway, the so-called Hispanic Corridor, between the western Tethys and the eastern Pacific Ocean during the upper Bajocian Parkinsoni Zone. The discovery of this upper Bajocian Dimorphinites assemblage provides a new biochronostratigraphic horizon in the Tarapaca Basin and an interoceanic correlation point for the latest Bajocian.

The Romaine Formation of the Mingan Islands, Québec, contains a limited trilobite fauna of five genera (Bolbocephalus, Peltabellia, Petigurus, Strigigenalis, Strotactinus) with Lower Ordovician Ibexian (Floian) affinity, succeeded by two genera (Acidiphorus, Pseudomera) of early Middle Ordovician Whiterockian (Dapingian) affinity. Trilobites of later Whiterockian (Darriwillian) affinity are more abundant in the overlying Mingan Formation, with 29 genera (Amphilichas, Bathyurus, Calyptaulax, Ceraurinella, Cybeloides, Dolichoharpes, Encrinuroides, Eobronteus, Eorobergia, Failleana, Glaphurina, Glaphurus, Hibbertia, Hyboaspis, Illaenus, Isotelus, Kawina, Nieskowskia, Phorocephala, Pandaspinapyga, Pliomerops, Remopleurides, Sphaerexochus [including S. valcourensis n. sp.], Sphaerocoryphe, Stenopareia, Thaleops, Thulincola, Uromystrum, and Vogdesia). Lectotypes are selected for Mingan species of Illaenus, Peltabellia, Petigurus, Sphaerexochus, Stenopareia, and Thaleops. A number of genera form biofacies which can be related to lithofacies. Taken together with Chazy Group and Northwest Territories trilobite faunas, Mingan trilobites provide critical information on late Whiterockian trilobite distributions in Laurentia in far more detail than seen in the stratotype area of Nevada.

Plastomenidae is a poorly diagnosed clade of extinct soft-shelled turtles (Trionychidae) known from the Campanian to Eocene of North America. Five skulls, a mandible, two carapaces, and numerous plastral remains from the Hell Creek Formation (Late Cretaceous, Maastrichtian) of North Dakota and Montana are referable to Gilmoremys lancensis nov. comb., a taxon previously known from a carapace and xiphiplastron only. Gilmoremys lancensis is diagnosed by a carapace that is covered by elongate sinusoidal grooves, distally expanded second costals, hyoplastral shoulders, an extensive secondary palate with accessory ridges, an extremely elongate mandible, a contribution of the parietal to the wall of the orbit, and a posterior ossified narial canal. A phylogenetic analysis of all well-known plastomenid turtles establishes Gilmoremys lancensis as the most basal known plastomenid and reveals that cranial characters are more reliable in diagnosing plastomenid turtles, in particular the contribution of the parietal to the orbit wall and the extensive secondary palate. All plastomenid turtles with a locked entoplastron are placed in Hutchemys. Assuming that all taxa are monophyletic, the phylogenetic analysis implies that the G. lancensis lineage is the only one to go extinct at the K/T boundary, whereas the four remaining plastomenid lineages survive. Extensive ghost ranges are nevertheless apparent. Taphonomic considerations indicate that G. lancensis was a riverine turtle, whereas more derived plastomenids preferred swampy habitats.

The obolellates represent a poorly understood group of the oldest known cosmopolitan calcareous rhynchonelliform brachiopods. They made their first appearance in the early Atdabanian and became extinct at the end of the Middle Cambrian. Consequently, any information concerning the soft anatomy of this ephemeral lineage of brachiopods has great phylogenetic significance. This is the first report on two specimens of an obolellate with fine preservation of soft parts including the pedicle, marginal setae and possible imprints of a spiral lophophore, recovered from the early Cambrian Chengjiang Konservat Lagerstätte of Kunming, southern China. The setae are thin and densely fringed along the shell margin. The stout pedicle is distinctly composed of densely stacked tabular bodies, lacking a central coelomic lumen; it emerges through a possible foramen, and slightly tapers posteriorly with the distal end attached to exoskeletons of other organisms.

New shell microstructure data for the Triassic pectinid Pleuronectites reinforce shell morphological data suggesting that its family Pectinidae was derived from the superfamily Aviculopectinoidea and not from the Pernopectinidae-Entolioidesidae-Entoliidae clade. This would make the superfamily Pectinoidea, as defined by recent authors, polyphyletic. This would also imply that alivincular-alate ligaments evolved independently in the Pernopectinidae-Entolioidesidae-Entolidae and Pectinidae clades.

The taxonomy and phylogenetic position of the hadrosaurid dinosaur Barsboldia sicinskii is revised. This species is rediagnosed based on the unique combination of iliac central plate with depth/length ratio less than 0.8 and sacral vertebrae with distally ‘clubbed’ neural spines at least four times higher than their centra. A maximum parsimony analysis of 47 hadrosauroid (39 hadrosaurid) species does not support the purported lambeosaurine affinities of B. sicinskii, but recovers this form as a basal saurolophine hadrosaurid based on unambiguous synapomorphies of the ilium. This result increases the diversity of saurolophine taxa in Asia, a continent with a hadrosaurid fossil record so far dominated by lambeosaurines. Finally, several vertebral and iliac characters previously regarded as diagnostic of Lambeosaurinae are discussed and shown to be uninformative from a taxonomic or phylogenetic standpoint.

The evolutionary history of the major boring-bivalve superfamily Pholadoidea remains unclear. Opertochasma somaensis n. sp., preserved in situ in fossilized wood from upper Kimmeridgian to lower Tithonian strata within the Upper Jurassic shallow marine Nakanosawa Formation, northeast Japan, is described. This new species represents one of the oldest body fossils of pholadoidean boring-bivalves and the first fossil record from the Jurassic in the circum-Pacific regions. The authochthonous occurrence in fossilized wood, the presence of microscopic file-like sculpture on the anterior shell slope, the short clavate burrow, and other shell features demonstrate that O. somaensis n. sp. was a filter-feeding, obligate wood-borer with anterior-boring locomotion, and also that the complex shell morphology unique to Pholadoidea was established by the Late Jurassic. The documentation of the new species and taxonomic review on the Jurassic species previously described, show that the superfamily Pholadoidea was widely distributed along the Northern Hemisphere middle latitudes in the latest Jurassic. The Pholadoidea likely evolved by exploiting woody substrata which had become abundant during the Late Jurassic with floral diversification in the middle latitudes. It is notable that the xylophagous mode of life, referable to modern Teredinidae and Xylophagaidae, was most probably established in the Jurassic and provided an important background for the establishment of chemosynthesis-based, sunken wood-associated communities.

Early Permian fusulinids from both northern and southern parts of the Baoshan Block (western Yunnan, Southwest China) are illustrated and compared with coeval fusulinid faunas from other northern peri-Gondwana areas to disclose paleogeographic information. Systematic study of collected fusulinid materials and examination of published data from the Dingjiazhai area, northern Baoshan Block, show that fusulinids there include Eoparafusulina pseudosimplex and Pseudofusulina macilenta. Fusulinids from the Aluotian Section, southern Baoshan Block, consist of P. minitumidiscula n. sp., P. macilenta, P. tumidiscula, E. pseudo simplex, E. aff. E. laudoni, and E. sp. Early Permian fusulinids from both northern and southern Baoshan Blocks are dominated by Pseudofusulina and Eoparafusulina species and they are similar to those from Central Pamir, South Afghanistan, East-Central Iran, Central Oman, East Hindu Kush and northern Karakorum, revealing a Sakmarian to Artinskian age. Moreover, detailed comparison shows that the Early Permian fusulinid assemblage from the Baoshan Block is more similar to those from East-Central Iran, Central Pamir and South Afghanistan. This implies that the Baoshan Block may have been near those areas during the Early Permian.

The early Late Carboniferous rocks of the Guandacol Formation in western Argentina preserve the glacial to postglacial transition. In the study area, this unit has been divided in three intervals: 1) a lower diamictitic interval; 2) a middle interval chiefly composed of mudstone, and 3) an upper sandstone-dominated interval. The lower interval records infill of a fjord incised into the underlying Ordovician limestone. The middle and upper intervals reflect postglacial sedimentation. Four ichnotaxa, occurring as both discrete and compound trace fossils, are documented from the lower and middle intervals of the Guandacol Formation. Diplopodichnus biformis and Cruziana diplopoda n. isp. occur in the thinly bedded stratified diamictite in the upper section of the lower interval. These deposits record sedimentation from debris flows with dropstones reflecting overprinting of ice-rafting and rain-out processes. Cruziana cf. problematica and Rusophycus carbonarius are present in very-fine to fine-grained sandstone layers interbedded with dropstone-bearing mudstone in the lower section of the middle interval. These deposits record the interplay of suspension fall-out sedimentation, ice-rafting, rain-out processes, and storm waves. The presence of linguliformean brachiopods in coeval beds nearby strongly suggests marine influence and that brackish-water conditions prevailed during the early phase of the transgression. Harsh paleoenvironmental conditions may explain the small size of the trace fossils and the low ichnodiversity in comparison to that expected in fully marine environments. The morphology of the trace fossils as bilobate ridges and furrows ornamented with scratch marks indicates that the structures were produced by arthropods, most likely trilobites and/or notostracans. Although the possibility that different ichnotaxa have resulted from changes in burrowing behaviors can not be completely disregarded, the fact that distinct Cruziana ichnospecies display non-overlapping facies distribution may suggest their production by different arthropods.

A neptunoceratid cephalopod, Texanoceras jacksboroensis n. gen. n. sp., is described from the Virgilian (Upper Pennsylvanian) Graham and Caddo Creek Formations in Texas, North America. The family Neptunoceratidae was previously represented by a single genus, Tetrapleuroceras. This new material provides important emendations to the diagnostic concept of the enigmatic family including shell orientation, mature modification and siphuncular structure. Although higher taxonomic position of Neptunoceratidae is difficult to determine at present, morphologic similarities between the family and the orthoceratid (?) family Brachycycloceratidae are discussed.

The discovery of platy limestone deposits in northeastern Mexico has led to the collection of well-preserved stramentids of early Turonian age from Vallecillo, state of Nuevo León, and of early Coniacian age from El Carranza, state of Coahuila. Stramentum (Stramentum) pulchellum (Sowerby, 1843) colonized the ammonite shells during the lifetime of the animals, occasionally in two subsequent generations. Colonization of the ammonite shell by Stramentum (S.) pulchellum was hindered by strong ornamentation only. The ammonites did not interfere with their epizoans. Colonization during lifetime shows that these ammonites dwelled in well-oxygenated water levels near the surface, and most stramentids were embedded alive. The known paleobiogeographic occurrence of Stramentum (S.) pulchellum and its long stratigraphic occurrence are considerably enlarged by our findings. The pseudoplanktonic mode of life of Stramentum, and attachment to ammonite shells, may have been a response of a once benthic organism to repeated oxygen-deficient conditions on the seafloor of mid-Cretaceous oceans, i.e., to oceanic anoxic events (OAEs).

The early Paleocene Purgatorius Van Valen and Sloan is the most primitive plesiadapiform primate yet discovered, mostly known from middle to late Puercan strata in Montana, deposited during the interval C29N of the geomagnetic polarity time scale. Here we describe Purgatorius coracis n. sp. from the Ravenscrag Formation, at the Rav W-1 horizon, Medicine Hat Brick and Tile Quarry, southwestern Saskatchewan. This horizon occurs within C29R, making P. coracis the earliest known primate, while strengthening the evidence that plesiadapiforms, and hence primates, originated and underwent their initial evolutionary diversification in North America. Most North American mammalian local faunas correlating with C29R have been assigned to the Pul (earliest Puercan) interval zone, but the taxonomic composition of the mammals accompanying P. coracis at Rav W-1 more resembles local faunas of Pu2 age. The occurrence at Rav W-1 of Pu2 aspect mammals within C29R agrees with similar occurrences at the Hiatt and PITA Flats localities in Montana and North Dakota, also possibly correlated with C29R. The evidence from these three sites, all in the Williston Basin, suggests that in some areas of the Western Interior Pu2 aspect local faunas were coeval with those of latest Pu1 age, having evolved earlier than has commonly been assumed.

Jurassic–Cretaceous ammonites are particularly robust fossil tools in global stratigraphy and correlation. The successive evolution and extinction of these cephalopod mollusks was so rapid that many ammonite zones are no more than one million years in duration. A well-preserved ammonite specimen from the Fortissimo-1 core, Browse Basin, NW Australia is assignable to the widespread latest Jurassic dimorphic berriaselline genus, Blanfordiceras Cossmann, recorded previously from the Spiti area, Nepal, Tibet, Madagascar, Papua-New Guinea, Antarctica, and southern South America. This is the first report of ammonites of this age in the Australian region. The evolute shell of an estimated 90-100 mm diameter (when extrapolated) and pronounced ornamentation of variably bifurcating, curvilinear and flexuous ribs, intercalated with simple, non-bifurcating ribs, is consistent with Blanfordiceras wallichi (Gray, 1832), which has traditionally been restricted to the uppermost Tithonian Stage, ca. 146.5-145.5 Ma, but may well have survived into the earliest part of the Berriasian. The first recorded occurrence of this ammonite in Australia fills an anomalous absence in the paleobiogeographic distribution of Jurassic–Cretaceous boundary ammonites in the Indo-SW Pacific Subrealm with important implications for the calibration of offshore rocks and wells in Australia.

Twelve brachiopod species are described from the Cisuralian (Early Permian) Kungurian horizon of a large limestone block in the Middle Jurassic accretionary complex at Hatahoko in the Mino Belt, central Japan. Most species of the Hatahoko fauna are known from the Kungurian to lowest Guadalupian (Middle Permian) of West Texas, U.S.A. The Kungurian age is also indicated by the associated conodonts in the same limestone block. The Hatahoko brachiopod fauna, as well as some other previously-reported Guadalupian brachiopod faunas, exhibits a very strong paleobiogeographical affinity with the faunas in West Texas, U.S.A. Therefore it can be interpreted as a fauna which inhabited reef-seamount complexes close to North America in the mid-equatorial region of the Panthalassa in the late Early Permian, rifted westwards thousands of kilometers, and finally accreted onto the Japanese Island when the Western Pacific Plate subducted beneath the Eurasian Plate during the Jurassic.

A new arthropod Jugatacaris agilis n. gen. n. sp. with excellent soft anatomy is reported from the Early Cambrian Chengjiang biota. Its “bivalved” carapace with a dorsal fin-like fusion is distinct from those of other Cambrian arthropods. A pair of stalked eyes and a prominent median eye protrudes the carapace anteriorly. The cephalon, attaching to the carapace through the lateral adductor muscles at maxillary segment, bears an antennule, antenna and mandible. The trunk is comprised of a large number of segments (varying from 55 to 65), two-thirds of which is covered by the carapace. Each segment, except for the posterior three to five, carries a pair of uniform biramous appendages. The endopodite is composed of 30 podomeres and a terminal claw. The oar-shaped exopododite is fringed with filaments and distally bears a broad setiferous lobe. Trunk terminates with a conical telson and a pair of broad furcal rami serving as steering devices. Internal features like gonad and gut have also been found. The presence of the food groove combined with other morphological features indicates that Jugatacaris was a filter feeder. The appendages design associated with the overall body-plan supports the view that Jugatacaris is a crustaceanomorph. The accurate phylogenic assessment will remain the subject of debate until more information becomes available.

Lobopodians, which diversified and flourished in the Cambrian seas, have long drawn much attention in that not only their extant close relatives, onychophorans and tardigrades, but euarthropods (Chelicerata, Myriapoda, Crustacea, and Hexapoda) may have been deeply rooted in stem-group lobopodians. Antennacanthopodia gracilis new genus and species is described and interpreted here as an “unarmoured” lobopodian from the Chengjiang fossil Lagerstätte (Early Cambrian, —520 Ma), Yunnan, southwestern China. This animal shares with other known Cambrian lobopodians such plesiomorphies (primitive characters) as onychophoran-like overall appearance; a metamerically segmented body covered by slightly sclerotized cuticle, and paired, unjointed lobopodal legs. Antennacanthopodia is also featured by a pair of frontal antennae, potential ocellus-like lateral visual organs, second antennae, a straight, voluminous midgut, diminutive spines arrayed on the leg and the trunk, well-developed leg musculature, highly sclerotized terminal leg pads, and presumptively a pair of posteriormost appendicules. This new taxon, with innovative characters (autapomorphies), furthers our understanding of early lobopodian diversification. Antennacanthopodia is considered closely allied to extant Onychophora based on considerable anatomical similarities. Taken together its “two-segmented” cephalization and appendage-bearing “ocular segment”, this new form may shed some new light on the arthropod groundplan.

The enigmatic pentameride brachiopod Noetlingia Hall and Clarke, 1893 is revised and its stratigraphic range corrected. The type species Noetlingia tscheffkini occurs only within the upper Darriwilian (Ordovician) of the East Baltic and not in the Silurian as previously assumed. Thus, presently defined, the superfamily Porambonitoidea does not cross the boundary between the Ordovician and Silurian systems. Two other species occurring in the Lower to Middle Ordovician of South China and North America are assigned to Noetlingia.