Our knowledge of the foraminiferal fossil record of Antarctica is notoriously patchy but still offers us an overview of its Cenozoic faunas. Few occurrences have been reported for the continent, with deep-sea assemblages described mainly for its eastern portion. Here we describe 21 taxa of large agglutinated foraminifers from the Miocene Hobbs Glacier Formation and the Plio-Pleistocene Weddell Sea Formation on Seymour Island, West Antarctica, including the gigantic Ammodiscus vastus new species. Most of them consist of genera or species typical of deep-sea agglutinated assemblages. All specimens are completely filled and partially covered by lithified micrite. This, along with the postfill fragmentation of some tests, indicates their re-elaboration from older deposits. Because all of these foraminifers share the same taphonomic features and most of them represent taxa associated with deep-sea settings, they probably represent a flysch-type assemblage from an unknown deposit that was eroded and had its microfossils scattered through post-Paleogene sediments. A Paleocene age for this putative assemblage is indicated by the presence of Reticulophragmiun garcilassoi (Frizzell, 1943), a Paleocene index fossil, and by its association with the Cretaceous–Paleocene Ammodiscus pennyi Cushman and Jarvis, 1928. If taken as a coherent foraminiferal assemblage, it represents one of the few deep-sea assemblages known for West Antarctica, and the first flysch-type assemblage recognized for the Antarctic Cenozoic. In addition, it would show that the Paleocene foraminiferal communities of the West Antarctica's deep-sea floor were more like their Pacific counterparts than their Atlantic equivalents.

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A diverse labechiid stromatoporoid assemblage that includes 16 species in 8 genera was found in the Upper Ordovician Xiazhen Formation (mid–late Katian) at Zhuzhai, Jiangxi Province of South China. The assemblage is characterized by a combination of (1) North China provincial species succeeding from their origination in the Darriwilian, including Pseudostylodictyon poshanense Ozaki, 1938, Labechia shanhsiensis Yabe and Sugiyama, 1930, Labechia variabilis Yabe and Sugiyama, 1930, and Labechiella regularis (Yabe and Sugiyama, 1930) and (2) South China endemic species, including three new species (Labechia zhuzhainus Jeon n. sp., Labechiella beluatus Jeon n. sp., Sinabeatricea luteolus Jeon n. gen. n. sp.), and four species in open nomenclature (Rosenella sp., Cystostroma sp., Pseudostylodictyon sp., and Labechia sp.). The finding of Labechiella gondwanense Jeon n. sp., Stylostroma bubsense Webby, 1991, Stylostroma ugbrookense Webby, 1991, and Thamnobeatricea gouldi Webby, 1991 in the formation indicates that Tasmania was closely related to South China and had a closer paleobiogeographical relation with peri-Gondwanan terranes than with Laurentia. In addition, the occurrences of Labechia altunensis Dong and Wang, 1984 and Stylostroma species support a close biogeographic link between Tarim and South China through the Middle to Late Ordovician interval, corresponding with the results from other fossil groups such as brachiopods, conodonts and chitinozoans. The diverse labechiids from the Xiazhen Formation improve our understanding of the diversity of Ordovician stromatoporoids in peri-Gondwanan terranes and the biogeographic affinities among Australia (especially Tasmania), Tarim, and South China.

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The fossil record of octocorals from Cenozoic marine strata of western North America is quite limited, and they have not been reported previously from rocks in Washington State, USA. Two late Oligocene specimens from the upper part of the Lincoln Creek Formation in western Washington, referred to Radicipes? sp., are the first fossil record of the family Chrysogorgiidae. The family Isididae is represented by an internode and two holdfasts identified as Isidella sp. collected from the Oligocene Pysht Formation, along with specimens questionably identified as Lepidisis sp., possibly the first fossil record for this genus. Together, these are the first confirmed fossils of the Alcyonacea from north of California in western North America. The axes of sea pens from several late Eocene or early Oligocene localities in the Lincoln Creek Formation in the central part of western Washington, and the Pysht and Makah formations on the north side of the Olympic Peninsula, are the first fossil record for the Pennatulacea from western North America; all are tentatively referred to the genus ‘Graphularia’. Large axes from the Lincoln Creek Formation and Makah Formation are referred to ‘Graphularia’ (?) aff. sasai, because they are similar to the species known only from late Eocene and early Oligocene rocks in Japan.

The Cambrian stratigraphic succession of the Pyrenees (SW Europe) has undergone a complex Variscan and Alpine tectonothermal history leading to marked metamorphism and development of cleavage networks, which might partly explain the lack of Cambrian fossiliferous beds. This gap has traditionally precluded its paleobiogeographic and biostratigraphic relationships with other neighboring peri-Gondwanan units. Correlations are only based on lithostratigraphic comparisons and radiometric constraints. In this general scheme, the Terrades inlier (Gerona Province, Spain) provides the only significant and indisputable ‘early Cambrian’ fossil record of the Pyrenees. This predominantly siliciclastic outcrop consists of multiple patch reefs and bioherms having yielded archeocyaths dated at Cambrian Epoch 2, Age 3. This paper describes, for the first time, the microfossil assemblage included in the archeocyathan-microbial reefal complex that crops out in the Terrades inlier to clarify its age and affinities with surrounding tectonostratigraphic units. Reefal flanks of patch reefs have yielded bradoriids, brachiopods, molluscs, tommotiids, chancelloriids, hyoliths, and the problematic fossil (and chronostratigraphically significant) Rhombocorniculum cancellatum Cobbold, 1921. In addition to confirming the previously assigned age of the succession, the recovered fauna emphasizes strong affinities with the surrounding Occitan Domain (Montagne Noire, southern Massif Central, France) and Sardinia (Italy). Along with lithostratigraphic comparison and tectonic considerations, this further supports the recent reconstructions positioning the Pyrenean domain between the Montagne Noire (to the southwest) and Sardinia (further to the northeast) on the Gondwana margin during Cambrian times.

We report the finding of two partial specimens of Cryptolepas rhachianecti (Cirripedia, Coronulidae), a coronulid barnacle known only to inhabit the skin of gray whales (Eschrichtius robustus), in Pleistocene-aged sediments from the Canoa Basin, Ecuador. While the historical range of gray whales includes the North Pacific and North Atlantic, to our knowledge this is the first inferred evidence of a gray whale population having resided within the South Pacific. We describe the two Cryptolepas rhachianecti fossils, use isotopic analysis to investigate evidence of migration in their host whales, and discuss their implications for our understanding of gray whale evolutionary history.

A highly diverse fauna of dromioid brachyurans from the Serraduy Formation (lower Eocene) in the western Pyrenees (Huesca, Spain) is described and illustrated. Recorded taxa are Mclaynotopus longispinosus new genus new species, Torodromia elongata n. gen. n. sp., Basidromilites glaessneri n. gen. n. sp., ?Basidromilites sp., Sierradromia gladiator n. gen. n. sp., Kromtitis isabenensis n. sp., and ?Basinotopus sp. Other European outcrops have yielded dromioids in association with specific environments, likely coral and sponge reef and siliciclastic soft bottoms; but the present material constitutes the most diverse dromioid assemblage from the lower Eocene worldwide. These dromioids co-occurred with a rich invertebrate fauna and lived near coral–algal reef mounds. Sedimentological data suggest that most of the fauna accumulated in fore reef settings as a result of storm activity. The present material greatly increases the diversity of known dromioid crabs associated with Eocene reef environments.

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The Museo de La Plata houses numerous Miaolingian and Furongian fossils from the southern Precordillera of Mendoza, western Argentina, collected by Ángel V. Borrello during the 1960s. Early Miaolingian (Wuliuan) trilobites from these collections are described herein. The specimens studied come from allochthonous limestone blocks (San Isidro Olistoliths) of key fossiliferous localities of the San Isidro area (Cerro Martillo, Quebrada Oblicua, Quebrada Empozada, Quebrada San Isidro). Taxa comprise Athabaskia anax (Walcott), Glossopleura leona Lochman, Kootenia aff. K. incerta (Rusconi), Kootenia crassa Fritz, Oryctocephalites reynoldsi (Reed), Zacanthoides sp., Spencia? sp., Amecephalus normale? (Resser), Amecephalus laticaudum? (Resser), and Amecephalus sp. This assemblage is representative of the North American Glossopleura walcotti Zone, and closely allied to faunas from the Great Basin (Spence Shale), Sonora, and to a lesser extent from northwestern Idaho.

Gennaeocrinus tariatensis new species is an Emsian (Devonian) monobathrid crinoid described from the Tarvagatay Terrane of Mongolia and part of the Central Asian Orogenic Belt. The Tarvagatay Terrane is an arc terrane that accreted to the southern margin of the Siberian Craton. Gennaeocrinus tariatensis was collected from the Emsian Tariat Formation, a terrigenous sequence of conglomerates, sandstones, and siltstones. Associated faunas include brachiopods, molluscs, and rare tabulate corals. Although Gennaeocrinus is well known from the Emsian–Givetian of North America, this is the first occurrence of the genus outside Laurussia. Mongolia is a large country with many terranes having varied paleogeographic, sedimentological, and tectonic histories; but reports of Paleozoic echinoderms are rare. The crinoid occurrence from the Tariat Formation is from the same age as previously described Emsian crinoids from the Chuluum Formation but differs significantly in sedimentology, paleogeography, and paleolatitude.

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The Lochkovian (Lower Devonian) conodont biostratigraphy in China is poorly known, and conodont-based subdivision schemes for the Lochkovian in peri-Gondwana (the Spanish Central Pyrenees, the Prague Synform, Sardinia, and the Carnic Alps) have not been tested in China. Therefore, we studied conodonts from the lower part (Bed 9 to Bed 13) of the Shanjiang Formation at the Alengchu section of Lijiang, western Yunnan to test the application of established subdivision schemes. The conodont fauna is assignable to 12 taxa belonging to eight genera (Ancyrodelloides, Flajsella, Lanea, Wurmiella, Zieglerodina, Caudicriodus, Pelekysgnathus, and Pseudooneotodus), and enables recognition of two chronostratigraphical intervals from the lower part of the Shanjiang Formation. The interval ranging from the uppermost part of Bed 9 to the upper part of Bed 10 belongs to the lower Lochkovian; whereas an interval covering the uppermost part of Bed 11 to the upper part of Bed 13 is correlated with the upper half of the middle Lochkovian. The Silurian-Devonian boundary is probably located within Bed 9, in the basal part of the Shanjiang Formation. However, the scarcity of specimens precludes definitive identification of bases of the lower, middle, and upper Lochkovian as well as other conodont zones recognized in peri-Gondwana.

Temnospondyl amphibians are common in non-marine Triassic assemblages, including in the Fremouw Formation (Lower to Middle Triassic) of Antarctica. Temnospondyls were among the first tetrapods to be collected from Antarctica, but their record from the lower Fremouw Formation has long been tenuous. One taxon, ‘Austrobrachyops jenseni,’ is represented by a type specimen comprising only a partial pterygoid, which is now thought to belong to a dicynodont. A second taxon, ‘Cryobatrachus kitchingi,’ is represented by a type specimen comprising a nearly complete skull, but the specimen is only exposed ventrally, and uncertainty over its ontogenetic maturity and some aspects of its anatomy has led it to be designated as a nomen dubium by previous workers. Here, we redescribe the holotype of ‘C. kitchingi,’ an undertaking that is augmented by tomographic analysis. Most of the original interpretations and reconstructions cannot be substantiated, and some are clearly erroneous. Although originally classified as a lydekkerinid, the purported lydekkerinid characteristics are shown to be unfounded or no longer diagnostic for the family. We instead identify numerous features shared with highly immature capitosaurs, a large-bodied clade documented in the upper Fremouw Formation of Antarctica and elsewhere in the Lower Triassic. Additionally, we describe a newly collected partial skull from the lower Fremouw Formation that represents a relatively mature, small-bodied individual, which we provisionally refer to Lydekkerinidae; this specimen represents the most confident identification of a lydekkerinid from Antarctica to date.

Sloths were among the most diverse groups of land vertebrates that inhabited the Greater Antilles until their extinction in the middle-late Holocene following the arrival of humans to the islands. Although the fossil record of the group is well known from Quaternary deposits in Cuba, Hispaniola, and Puerto Rico, remains from older units are scarce, limiting our understanding of their evolution and biogeographic history. Here we report the oldest known fossil ground sloth from Hispaniola, represented by an unassociated partial tibia and scapula that are recognized as a single taxon from the late Miocene-early Pliocene of the Dominican Republic. The combination of characters observed on the tibia suggests a close relationship with Megalocnus, otherwise only known from the Pleistocene–Holocene of Cuba. These fossils fill a temporal gap between those previously known from the early Miocene of Cuba and those from Pleistocene–Holocene deposits in the region and provide additional support for a continuous presence of the group in the Greater Antilles since the Oligocene.

A recent study on the fossil history of North American woodrats and their relatives suggested that the Neotomini includes two subtribes: the Neotomina (woodrats; Tsaphanomys, Neotoma, Hodomys, Xenomys) and Galushamyina (reprats: Protorepomys, Galushamys, Miotomodon, Repomys, Nelsonia). The extinct Miocene Lindsaymys was proposed as a possible early neotominan, but not formally included in the Neotomini. In other studies, two extinct genera, Basirepomys and Paronychomys, occasionally have been treated as related to neotominans, but their ancestry had not been formally explored in detail. We performed a phylogenetic analysis on representatives of all genera with 40 dental and mandibular characters likely to be preserved in fossil material. The analysis resulted in a single most parsimonious tree supporting a neotominan-galushamyinan tribal classification of the Neotomini, and securely placed Lindsaymys within the Neotomina. None of the Basirepomys and Paronychomys species or Protorepomys bartlettensis nested within the Neotomini. The three Basirepomys species, possibly a paraphyletic group, are not closely related to Repomys, and Paronychomys (minus P. shotwelli = Tsaphanomys shotwelli) is not closely related to Onychomys, but is a possible sister group to the Neotomini. With the understanding that further study may remove it from Protorepomys, P. bartlettensis is tentatively retained within the genus, representing a relatively underived species possibly ancestral to both neotominan clades. Neotoma species of the extinct subgenus Paraneotoma and extant Neotoma may be paraphyletic at the generic level, but that determination will require further study.

A latest Paleocene charophyte flora collected from the South Gobi area in the Junggar Basin, western China, includes the geographically widespread taxa Peckichara torulosa var. varians (Dollfus and Fritel, 1919) Sanjuan, Vicente, and Eaton, 2020, Lychnothmanus vectensis (Groves, 1926) Soulié-Märsche, 1989, and Gyrogona lemani capitata Grambast and Grambast-Fessard, 1981. Lychnothmanus vectensis (as Lychnothmanus aff. L. vectensis) is known from the Cretaceous–Paleocene transition in eastern China and the latest Paleocene in western China, with likely additional records from the United States (Utah). The earliest European records of L. vectensis are from the late Eocene to early Oligocene in Spain, France, and England. Similarly, the oldest record of G. lemani capitata is from the latest Paleocene in the South Gobi area, with younger records from the middle Eocene of France. These latest Paleocene gyrogonite assemblages demonstrate the origin of these charophyte lineages in Asia. The dispersal of these charophytes from Asia to Europe in the middle to late Eocene appears to have occurred before the retreat of the Turgai Strait in both the Tarim area and the Siberian Basin by the end of the late Eocene and before the “Grande Coupure” in Europe and the Mongolian Remodelling in Asia during the Eocene–Oligocene transition. We hypothesize that waterbirds may have facilitated this intercontinental dispersal, and that idea is supported by the shared occurrence of avian groups in Central Asia and Europe in the middle and late Eocene.

Modular coral-like fossils occur in thrombolitic reefal beds at two stratigraphic levels within the Lower Ordovician (Floian) Barbace Cove Member of the Boat Harbour Formation, in the St. George Group of western Newfoundland. They are here assigned to Reptamsassia n. gen.; R. divergens n. gen. n. sp. is present at both levels, whereas a comparatively small-module species, R. minuta n. gen. n. sp., is confined to the upper level. Reptamsassia n. gen. resembles the Ordovician genus Amsassia in its phacelocerioid structure, back-to-back walls of adjoining modules, module increase by longitudinal fission involving infoldings of the wall, tabula-like structures that are continuous with the vertical module wall, and calices with concave-up bottoms. The new genus is differentiated by its encrusting habit, modules with highly variable growth directions and shapes throughout skeletal growth, and modules that may separate slightly or diverge from one another following fission. Together, Amsassia and Reptamsassia n. gen. are considered to represent a distinct group of calcareous algae, the Amsassiaceae n. fam., which possibly belongs to the green algae. The Early Ordovician origination of Amsassia followed by Reptamsassia n. gen. contributed to the beginning of the rise in diversity on a global scale and in reefal settings during the Great Ordovician Biodiversification Event. Reptamsassia minuta n. gen. n. sp. was an obligate symbiont that colonized living areas on its host, R. divergens n. gen. n. sp., with isolated modules of R. divergens n. gen. n. sp. able to persist in the resulting intergrowth with R. minuta n. gen. n. sp. This is the earliest known symbiotic intergrowth of macroscopic modular species, exemplifying the development of ecologic specialization and ecosystem complexity in Early Ordovician reefs.

Correct identification of fossil taxa is immensely important for dating molecular phylogenies and understanding when and how quickly modern biodiversity evolved. Fossils that are available for a clade of interest and can be directly incorporated in the phylogenetic analysis are considered primary sources of time calibration, whereas calibrations inferred from other studies are secondary (Arroyave et al., 2013). Studies of taxonomic groups that lack fossils must either expand their analyses to include fossilized outgroup lineages, use secondary calibrations, or use more problematic primary calibrations, e.g., vicariant geologic events. The use of vicariant geologic events to calibrate phylogenies poses the risk of circular reasoning, because the goal of many such studies is to determine how geologic events have affected diversification. Near et al. (2012) argued that fossil calibrations external to clades of interest, but still within the broader Actinopterygian (ray-finned fishes) tree, could be used as means of calibrating a generalized molecular clock, but internal calibrations are still valuable for refining such inferences (Arroyave et al., 2013).