The upper Bartonian–Priabonian shallow-marine deposits in the Biga Peninsula (NW Turkey) contain some hyaline larger benthic foraminifers (LBF) with a test architecture similar to ‘orbitoidiform’ foraminifers, but displaying some distinctive and complex morphological features that are recorded here for the first time. These coarsely porous specimens are characterized by a flat, disc-shaped, fragile, and smooth test with a layer of equatorial chambers/chamberlets, surrounded by poorly developed lateral chamberlets, never forming a discrete layer on either side of the equatorial layer. The nepionic stage is very distinctive because the bilocular embryonic apparatus is followed by a semi-rounded, notably large auxiliary chamber with a characteristic wavy outline, and consecutive cyclical chambers. The cyclical chamber arrangement is later transformed into annular cycles with numerous, complex arcuate- to cup-shaped chamberlets, as observed in equatorial sections. Bigaella orbitoidiformis Özcan, Mitchell, Pignatti, Simmons, and Yücel, n. gen. n. sp., is established for these specimens, and placed within the family Eoannulariidae Ferràndez-Cañadell and Serra-Kiel, emended herein. The new genus occurs together with Caudriella Haman and Huddleston and Epiannularia Caudri (both originally established from the American bioprovince) and the genus Linderina Schlumberger (found both in the Tethys and the American bioprovinces), together with other typical Western Tethyan LBFs. A comparison of the new genus with the aforementioned taxa is given.

The Nasep and Huns members of the Urusis Formation (Nama Group), southern Namibia, preserve some of the most diverse trace-fossil assemblages known from the latest Ediacaran worldwide, including potentially the world's oldest “complex” vertical sediment-penetrating burrows. These sediments record relatively diverse communities of bilaterian metazoans existing before the base of the Cambrian and an increase in the intensity of metazoan ecosystem engineering behaviors that could eventually produce profound changes in the character of the Phanerozoic sedimentary record (the “agronomic revolution”). Despite this, relatively little about this trace-fossil assemblage is known. We explore the Nasep–Huns transition at two localities in the Witputs sub-basin and describe the trace- and body-fossil diversity present in these horizons alongside a paleoenvironmental reconstruction. We document eight unique ichnotaxa from these localities, including well-preserved “probes” potentially left by priapulids. We also report the first occurrence of Corumbella from Namibia, helping to establish a biostratigraphic link between Namibia, Brazil, Paraguay, Iran, and the southwestern United States. Last, we find that several ichnotaxa, in particular small treptichnids, appear to be preferentially preserved on the bases of gutter casts, hinting at the potential existence of an unusual late Ediacaran preservational window with possible implications for timing the first appearance of key bilaterian behaviors.

A non-biomineralized arthropod, Protocaris marshi, was described from the lower Cambrian (Dyeran Series 2, Stage 4) of Parker's Cobble in northwestern Vermont in 1884. It represents the first fossil exhibiting Burgess Shale-type preservation to have been discovered. The locality was presumed to have been worked out and was not collected in a significant way for more than 100 years. Rediscovery of productive layers has yielded soft-bodied and lightly sclerotized taxa new to the locality, including the alga Fuxianospora, a possible priapulid, a radiodont, and a specimen tentatively assigned to Herpetogaster. New specimens of the sponge Leptomitus zitteli, the bivalved arthropod Tuzoia, and the chordate Emmonsaspis cambrensis provide additional information on those taxa, and multiple specimens allow a bivalved arthropod, Vermontcaris montcalmi new genus, new species, to be described. The primary mode of fossil preservation is as carbonaceous compressions. The Parker Quarry Lagerstätte complements the Kinzers Formation of Pennsylvania (also Series 2, Stage 4) in revealing the diversity of soft-bodied taxa on the southern margin of the paleocontinent Laurentia.

In the early Cambrian fossil record, triradial symmetry is typical for anabaritids and occurs among carinachitids. The former are an extinct group of minute benthic cnidarians covered with a calcareous tubular exoskeleton. The origin of the anabaritids is poorly understood, but previously reported triradial pyramid-shaped steinkerns and molds of the oldest conulariids, Vendoconularia, from the upper Ediacaran of the White Sea region suggested the anabaritids were closely related to conulariids. However, triradial symmetry could originate independently in different lineages in the late Ediacaran and early Cambrian. Herein we describe a new taxon, Ilankirus kessyusensis new genus new species, from the base of the Cambrian Stage 2 of the Olenek Uplift (Siberian Platform). These fossils occur as ornamented steinkerns in the shape of trilateral pyramids and lack any relics of a mineralized exoskeleton. Abundant plastic deformations and fractures of the casts suggest the organism was weakly if at all mineralized. The steinkerns are encrusted with a thin patina of iron-rich chlorite (chamosite) formed because of a multistage diagenetic replacement of authigenic glauconite (glauconite–berthierine–chamosite) under reducing conditions of oxygen-depauperate pore- and seawater. Both lacking two major autapomorphies of the crown-group conulariids (mineralized periderm and quadrate cross section of the oral region of the periderm), the late Ediacaran triradial Vendoconularia and Terreneuvian Ilankirus represent stem-group conulariids.

Silty noduliferous shales in the lower part of the Middle Ordovician (late Darriwilian 2) Taddrist Formation in the central Moroccan Anti-Atlas contain a unique assemblage of conulariids consisting of one species each of Archaeoconularia Bouček, 1939, Glyptoconularia Sinclair, 1952, and Pseudoconularia Bouček, 1939. Glyptoconularia antiatlasica new species, currently represented by a single three-dimensional specimen, is the first member of this extremely rare, highly autapomorphic genus to be described from outside of cratonic North America as well as the first Glyptoconularia from the Middle Ordovician. Pseudoconularia cf. P. grandissima (Barrande, 1867) and Archaeoconularia cf. A. exquisita (Barrande, 1867) most closely resemble species previously described from Middle and Upper Ordovician strata in the Prague Basin (Czech Republic), then located adjacent to North Africa. Anaconularia anomala (Barrande, 1867), previously known from the Upper Ordovician (Sandbian) Libeň and Letná formations in the Prague Basin, is documented for the first time from the Upper Ordovician (Katian) Upper Tioririne Formation of Morocco. In addition to extending the known stratigraphical and paleogeographical ranges of these conulariids, results of the present investigation add to the list of invertebrate taxa that appear to have originated during Early or Mid-Ordovician times in peri-Gondwana or south-polar Gondwana, and then migrated to the eastern margin of Laurentia, arriving there along with other cool-water taxa during the Sandbian-Katian transition.

Based on extensive new material, 2088 valves resulting from search sampling of ∼500 kg of sediment, the Pliocene chiton biodiversity of the Mondego Basin (Portugal) is reassessed. Twelve species were identified, assigned to seven genera. Eight species are new for the Pliocene of Portugal, as well as two of the genera: Hanleya, Acanthochitona. Two taxa are described as new: Ischnochiton loureiroi n. sp. and Lepidochitona rochae n. sp. Until now, the polyplacophoran European Neogene record was too poorly known to be of help in generating a clear picture of the Miocene to present-day biogeography of the group. This new wealth of data from western Iberia, in conjunction with recent data from the Loire Basin Upper Miocene assemblages (France), allows clarification the Late Miocene to Recent eastern Atlantic and Mediterranean biogeography of the Polyplacophora. The northern range of warm-water northeast Atlantic and Mediterranean Polyplacophora experienced a sharp contraction since, at least, Late Miocene to Early Pliocene times. Warm-water chiton species represented in the Upper Miocene of the Loire Basin of NE France (European-West African Province) and the Pliocene of the Mondego Basin of central-west Portugal (Pliocene French-Iberian Province) are today confined to the southern Mediterranean-Moroccan Molluscan Province.

The Upper Devonian sedimentary sequences of Central Armenia, which mainly consist of shallow water, mixed carbonate-siliciclastic deposits, contain abundant and diverse brachiopods that are dominated by spiriferides. Based on newly collected material from the lower Famennian Aramazdospirifer orbelianus brachiopod zone (coeval to the Palmatolepis crepida conodont zone) of Armenia, we here introduce two new cyrtospiriferid genera and fully document their type species, including their intraspecific variability. Pentagonospirifer n. gen. is a monospecific genus assigned to the subfamily Cyrtospiriferinae that is currently known only from the lower Famennian of Armenia; it is likely that its type species, P. abrahamyanae n. sp., evolved from the species Cyrtospirifer verneuili sensu Abrahamyan, known from the Frasnian and lower Famennian of Armenia. The second new genus, Tornatospirifer n. gen., is assigned to the subfamily Cyrtiopsinae and defined on the basis of one of the most biostratigraphically valuable cyrtospiriferid species, namely T. armenicus n. comb., described previously from the lower Famennian Aramazdospirifer orbelianus Zone of Armenia. It is likely that it evolved from a Frasnian ancestral stock of Tiocyrspis Sartenaer, known from northwestern Europe, which probably migrated during the early Frasnian to the north Gondwanan margin. A neotype is selected for Abrahamyan's species because the type material is lost. Epibionts (Cornulites, Hederella) attached to brachiopods are also documented for the first time from the Upper Devonian of Armenia.

Ordovician open marine Lagerstätten are relatively rare and widely dispersed, producing a patchy picture of the diversity and biogeography of nonmineralized marine organisms and challenging our understanding of the fate of Cambrian groups. Here, for the first time, we report soft-bodied fossils, including a well-preserved marrellomorph arthropod, fragmentary carapaces, and macroalgae, from the Late Ordovician (Katian) Upper Member of the Kirkfield Formation near Brechin, Ontario. The unmineralized elements and associated exceptionally preserved shelly biota were entombed rapidly in storm deposits that smothered the shallow, carbonate-dominated shelf. The marrellomorph, Tomlinsonus dimitrii n. gen. n. sp., is remarkable for its ornate, curving cephalic spines and pair of hypertrophied appendages, suggesting a slow-moving, benthic lifestyle. Reevaluation of marrellomorph phylogeny using new data favors an arachnomorph affinity, although internal relationships are robust to differing outgroup selection. Clades Marrellida and Acercostraca are recovered, but the monophyly of Marrellomorpha is uncertain. The new taxon is recovered as sister to the Devonian Mimetaster and, as the second-youngest known marrellid, bridges an important gap in the evolution of this clade. More generally, the Brechin biota represents a rare window into Ordovician open marine shelf environments in Laurentia, representing an important point of comparison with contemporaneous Lagerstätten from other paleocontinents, with great potential for further discoveries.

A Glyptagnostus reticulatus (Angelin, 1851)–bearing trilobite assemblage has been found from an unnamed Cambrian formation in the Northern Qilian Mountains area, of which geographical placement in the Cambrian is contested. Glyptagnostus reticulatus is a biostratigraphic indicator of the Furongian Series and Paibian Stage, and three agnostoid and six polymerid taxa from the Changgou section, Daliang area are described herein, along with conspecific forms from the nearby Chuancigou section. This well-preserved assemblage shows strong taxonomic affinity with northwestern Queensland, Australia, and western Hunan–eastern Guizhou, China, and likely comes from deep outer-shelf to slope setting associated with the Northern Qilian arc. It is consistent with other arguments that during the Cambrian, the Northern Qilian arc, along with the Hexi Corridor of the Alxa terrane, were more closely allied to South China than to North China.

Early “ptychoparioid” trilobites are likely to play a crucial role in determining the currently unresolved phylogenetic relationships among the numerous Cambrian libristomate clades. However, such phylogenetic analyses are hindered by the fact that many species and genera of early “ptychoparioids” are known from very limited material and are typically defined only on cranidial features. Herein, we report new “ptychoparioid” assemblages from the Saline Valley Tongue, Harkless Formation at Clayton Ridge, Nevada. These middle to upper Dyeran Stage (Cambrian Series 2, Stage 4) assemblages contain well-preserved early “ptychoparioids” that are represented by articulated exoskeletons as well as isolated cranidia, rostral plates, librigenae, thoracic segments, and pygidia, which together provide morphological details for the complete or nearly complete exoskeleton of three new genera and four new species: Anebocephalus silverpeakensis n. gen. n. sp.; Coenoides scholteni n. gen. n. sp.; Harklessaspis rasettii n. gen. n. sp.; and H. parvigranulosus n. gen. n. sp. Pending a formal phylogenetic analysis, it is deemed preferable to assign these taxa to new genera rather than to shoehorn them in to potentially ill-diagnosed existing genera. These new genera are compared to the Cambrian Series 2 taxa Crassifimbra and Eokochaspis, and the Miaolingian Series taxon Elrathina, which are similar in morphology and known from sclerites other than just cranidia.

Also documented in this study are the “ptychoparioids” Crassifimbra walcotti, Cr.? sp. A, Cr. sp. B, and “ptychoparioid” spp. A, B, C, and D from the Saline Valley Tongue and the overlying Mule Spring Limestone and lowermost Emigrant Formation.

Records of abnormal fossil arthropods present important insight into how extinct forms responded to traumatic damage and developmental complications. Trilobites, bearing biomineralized dorsal exoskeletons, have arguably the most well-documented record of abnormalities spanning the Cambrian through the end-Permian. As such, new records of malformed, often injured, trilobites are occasionally identified. To further expand the documentation of abnormal specimens, we describe malformed specimens of Lyriaspis sigillum Whitehouse, 1939, Zacanthoides sp. indet., Asaphiscus wheeleri Meek, 1873, Elrathia kingii (Meek, 1870), and Ogygiocarella debuchii (Brongniart, 1822) from lower Paleozoic deposits. In considering these forms, we propose that they illustrate examples of injuries, and that the majority of these injuries reflect failed predation. We also considered the origin of injuries impacting singular segments, suggesting that these could reflect predation, self-induced damage, or intraspecific interactions during soft-shelled stages. Continued examination of lower Paleozoic trilobite injuries will further the understanding of how trilobites functioned as prey and elucidate how disparate trilobite groups recovered from failed attacks.

A new specimen of the arachnid order Trigonotarbida is described from the Middle Pennsylvanian (lower Desmoinesian) Shelburn Formation of Indiana, which has previously yielded the remains of a phalangiotarbid. Two new trigonotarbid arachnid specimens are also described from the Middle Pennsylvanian (Desmoinesian) Senora Formation of Oklahoma. These are the first trigonotarbid specimens reported from Indiana and Oklahoma. The Indiana trigonotarbid belongs to the Eophrynidae, as indicated by distinct features such as the large tubercles on the dorsal surface of the opisthosoma and two pairs of terminal opisthosomal spines. This specimen is the first arachnid fossil to be imaged using a Multistripe Laser Triangulation scanner. The heavy dorsal tuberculation, lobed and subtriangular carapace, rounded clypeus, lack of terminal opisthosomal spines, and rounded opisthosoma on Oklahoma specimen FMNH PE 56932 indicate it belongs to the genus Aphantomartus, in Aphantomartidae. The other Oklahoma specimen, FMNH PE 56955, possesses opisthosomal tergites that are divided into five plates longitudinally as well as a subquadrate carapace, which identify it as a member of Anthracomartidae; its rounded opisthosomal margin shows it to belong to the genus Anthracomartus.

Ohiocrinus byeongseoni n. sp. from the Middle Ordovician (Darriwilian) Jigunsan Formation of South Korea in the Sino-Korean (North China) block is the oldest species of Ohiocrinus of the Cincinnaticrinidae and the first record outside Laurentia. O. byeongseoni is characterized by a loosely clockwise-coiled anal sac, isotomous branching throughout arms, long, slender xenomorphic column, and small lichenocrinid-type holdfast. The new species occurs in association with a deep-water siliciclastic environment, unlike the Laurentian species with a shallow-water carbonate environment. The monospecific crinoid assemblage is interpreted as parautochthonous, considering that the crinoids were reworked by relatively weak down-current probably caused by storm but preserved within the environment where they lived. The occurrence of O. byeongseoni presents a considerable spatiotemporal gap and ecologic disparity in evolution of Ohiocrinus and the Cincinnaticrinidae.

Parioxys ferricolus Cope, 1878 is a long-neglected taxon of dissorophid temnospondyls from the early Permian (Cisuralian) of Texas. Reexamination of the original material and preparation of a previously undescribed specimen shed some light on the ontogeny and reveal numerous eucacopine features. P. ferricolus is characterized by: (1) a preorbital region 1.5 times as long as the posterior skull table in juveniles and twice as long in adults, (2) a parietal only two-thirds the length of the frontal, (3) interpterygoid vacuities shorter than half the skull length, (4) choanae posteriorly extended, and (5) vomer with enlarged, V-shaped median depression. P. ferricolus is found nested with Kamacops acervalis Gubin, 1980, with which it shares synapomorphies in the palate, within the dissorophid clade Eucacopinae.

A new enantiornithine, Musivavis amabilis n. gen. n. sp., is reported from the Lower Cretaceous Jehol Biota in western Liaoning, China. The new taxon is similar to the bohaiornithids in the robust subconical teeth, bluntly expanded omal ends of the furcula, caudolaterally oriented lateral trabeculae with triangular distal ends of the sternum, and a robust second pedal digit. Yet it differs from members of Bohaiornithidae in several features recalling other enantiornithine lineages, such as the acuminate rostral ramus of maxilla, the shape of the coracoid lateral margin, the presence of craniolateral processes on the sternum, the proportions of the manual phalanges, and the unspecialized third pedal ungual phalanx. A comprehensive phylogenetic analysis of Mesozoic birds shows that homoplasy significantly affects the reconstruction of enantiornithine relationships. When all phylogenetic characters are considered of equal weight, Musivavis is reconstructed in a lineage related to a radiation of large-bodied enantiornithines including Bohaiornithidae and Pengornithidae. Alternative scenarios based on progressive downweighting of the homoplastic characters support more basal placements of the pengornithids among Enantiornithes, but do not alter the affinity of Musivavis as a member of the “bohaiornithid-grade” group.