To investigate early radiolarian evolution and phylogeny, exceptionally well-preserved materials from the middle Cambrian and Lower Ordovician were examined using laboratory-based and synchrotron X-Ray micro-computed tomography (MCT). From the middle Cambrian (Wuliuan–Drumian) Inca Formation of the Georgina Basin, three families, including one new family, the Fungomaculidae n. fam., have been recovered. Analysis of MCT three-dimensional models of radiolarians reveals significant intraspecific variations in Archeoentactinia incaensis Won in Won and Below, 1999 and A. hexactinia Won in Won and Below, 1999 with six morphotypes recognized. Two new species, A. heptactinia n. sp. and A. pentactinia n. sp, are established. The first median-bar-centered initial spicule was identified in a specimen of A. incaensis morphotype 4.

Specimens of Varispiculum ectospiculatum Won and Iams, 2015 from the Lower Ordovician (upper Floian) Cow Head Group, Newfoundland, are digitized with the aid of the Australian Synchrotron MCT. The exclusively spicular composition of V. ectospiculatum is recognized. Morphological comparison suggests possible phylogenetic affinity between A. incaensis and V. ectospiculatum. At least one Entactinarian lineage appears to have evolved from the point-centered spicular Echidninidae.

Additional detail revealed by closer examination of Archeoentactinia hexactinia Won in Won and Below, 1999 morphotype 2 includes the possibility that rays of the initial spicule are hollow. This previously unrecognized feature is significant in the broader context of the mode of skeletal growth and early radiolarian evolution.

UUID: http://zoobank.org/7edbe7fa-1238-4914-b57b-f455037e1b7e

Evidence suggests that trilobites experienced moderate diversification during the middle Permian, of which Pseudophillipsia Gemmellaro, 1892 is the most successful, with an unusually high number of species. However, it remains unclear whether their abundance reflects a stratigraphic trend or is specific to their habitat. To address this, we conducted a taxonomic study of Pseudophillipsia from the middle Permian (Capitanian) Kamiyasse Formation of the Southern Kitakami Terrane, Japan, and examined the burial processes to understand their habitat. Careful taxonomic analysis identified two species, Pseudophillipsia (Pseudophillipsia) spatulifera Kobayashi and Hamada, 1980 and Pseudophillipsia (Carniphillipsia) cf. Pseudophillipsia (Carniphillipsia) raggyorcakaensis Qian, 1981. The trilobites occur in both sandstone and mudstone, preserved as complete outstretched or enrolled specimens as well as disarticulated specimens, the majority of which are pygidia. Sedimentary facies indicate that the sandstone layer was formed in a shallow marine environment close to the lower shoreface, whereas the mudstone layer represents a slightly deeper environment, occasionally altered by storm flows. Based on biostratinomic features, the outstretched specimens with convex-up orientation must be autochthonous, whereas the enrolled specimens are interpreted as para-autochthonous, likely transported by storm flows. The greater the bioturbation, the greater the likelihood of the trilobite skeleton being disarticulated, particularly in mudstone layers. These findings suggest that Pseudophillipsia (Pseudophillipsia) spatulifera inhabited both sandy and muddy substrata, whereas Pseudophillipsia (Carniphillipsia) cf. Pseudophillipsia (Carniphillipsia) raggyorcakaensis was restricted to sandy environments. Given the limited geographic extent of the Kamiyasse Formation, we hypothesize that the appearance of Pseudophillipsia reflects a change in the sedimentary environment.

The geologically oldest known crinoid pentacrinoid larva is reported from Verulam Formation (Katian) from the Lafarge Cannifton Agg Quarry in Cannifton, Ontario, Canada. The entire specimen (arms, aboral cup, and incomplete column) is ~4.2 mm high with the aboral cup only ~1.3 mm high. The specimen is comparable in size to the early pentacrinoid larva of the living crinoid Metacrinus rotundatus Carpenter, 1885. As known, the morphology of this pentacrinoid larva does not correspond in all details with any adult crinoid in the Cannifton area or from the nearby Brechin Lagerstätte fauna, suggesting that considerable morphological change occurred during ontogeny of this taxon.

A diverse early Miocene (Burdigalian) turritelline-dominated assemblage (TDA) is documented from a single bed of the Nandana Member of the Gaj Formation, Dwarka Basin, western India. This study reports 42 gastropod species, including the description of four new species: ?Clelandella saurashtraensis n. sp., Jujubinus dwarkaensis n. sp., Cerithium bardhani n. sp., and Nassarius anisi n. sp. In addition, 30 species are discussed under open nomenclature. The TDA assemblage is notable for the high diversity among turritelline gastropods, with eight species identified across two genera, Turritella and Haustator. Petrographic studies and the foraminifera associations of Lockhartia sp., Miogypsina sp., Operculina sp., Quinqueloculina sp., and Ammonia sp., along with other foraminiferal groups such as nodosariids, milliolids, and rotalids, suggest that the TDA bed was deposited in tropical, warm, nutrient-rich, well-oxygenated conditions in subtidal–intertidal conditions.

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This study presents a comprehensive systematic analysis of a cold-water brachiopod fauna from the upper Cisuralian (lower Permian) Kharnuden Formation, exposed at the Hovsugol section in southeastern Mongolia. Taxonomic investigation identifies 40 species belonging to 28 genera, including three newly described taxa: Paramarginifera pentagona n. sp., Linoproductus planiconvexus n. sp., and Jilinmartinia hovsugolensis n. sp. Biostratigraphic evidence tentatively indicates a Kungurian age, with possible extension down into the Artinskian. The assemblage likely originated along the southern margin of the Siberian Craton, within the Paleo-Asian Ocean (PAO). The fauna exhibits strong biogeographic affinities with contemporaneous faunas from the Beishan orogenic belt (northwestern China), Inner Mongolia, South Primorye (Russia), and selected Japanese terranes, yet differs significantly from assemblages in Transbaikal and central-northeastern Mongolia. These contrasts support the presence of the Sino-Mongolian Seaway—a transitional marine corridor within the closing PAO. The fauna is characterized by elements of the northern Boreal biogeographic realm, with a dominance of cold-adapted and endemic taxa and a complete absence of paleotropical elements. Associated paleoecological indicators suggest the influence of cool-temperate conditions at a relatively high-latitude paleogeographic position as well as geographic isolation. This paleobiogeographic pattern sheds light on the responses of Permian marine ecosystems to plate convergence, latitudinal climate gradients, and oceanic current reorganization during the final stages of the PAO closure.

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Two Late Ordovician cornulitid species, Cornulites richmondensis (Miller, 1874) and Cornulites hemistriatus new species, from the Ellis Bay and Vaureal formations of Anticosti Island, eastern Canada, are each shown in this study to have a thick, punctate, cross-bladed lamellar, calcitic conch wall, a crested fold, a septate juvenile part, and endoconic chamber deposit. These Late Ordovician, free-living (i.e., nonencrusting) forms of Cornulites Schlotheim, 1820 have characters intermediate between Cornulites and the late Silurian-Devonian forms of Tentaculites Schlotheim, 1820, particularly by having incipient inner layers and poorly fused annuli, but lacking cornulitid-type vesicular microstructures. The described cornulitids are similar to brachiopods in their cross-bladed lamellae and pseudopunctae, but their lamellar layers are considerably finer and much less distinct than those of brachiopod shells.

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While the late Llandovery brachiopod faunas of South China are well documented, they are known almost exclusively from shallow-water settings. Here, we present a detailed study of a brachiopod fauna from the Ningqiang Formation (early to middle Telychian) at the Bifengguan section in Sichuan Province, South China. Quantitative analyses, including non-metric multidimensional scaling (NMDS) and network analysis, reveal three successive brachiopod associations. Significantly, the basal Aegiria–Epitomyonia association was characterized by the abundance of the deep-water indicator Epitomyonia. This represents the first definitive record of a deep-water (BA4) community within the Telychian Xiushan Fauna, which was previously thought to be restricted to shallower environments. This basal association is succeeded by the Aegiria–Megaspinochonetes and Fardenia–Striispirifer associations, and this complete succession indicates a shallowing-upward environmental trend from a BA4 to an upper BA3 setting. We interpret this shallowing trend as a response to regional uplift. The initial existence of this deep-water association was likely facilitated by the unique paleogeographical position of the locality, which likely provided a stable habitat for this deep-water community. This study expands the known ecological range of the Xiushan Fauna and underscores the critical role of local paleogeography in shaping benthic community structures during the early Silurian.

We report a new species of stem ibis (Threskiornithidae) from the early Eocene Fossil Butte Member of the Green River Formation. Rhynchaeites mcfaddeni n. sp. is represented by an articulated partial skeleton and was a diminutive species, with an estimated body mass of under 300 g. The holotype specimen is preserved in an unusual manner, leaving the skull, presacral vertebral column, wings, and feet in approximate life position despite the loss of the trunk, pelvis, tail, and upper legs. This peculiar mode of preservation may represent a case of the “stick ‘n’ peel” model of preservation, by which a portion of a carcass becomes firmly adhered to the sediment by substances released during decay. Like other members of the stem ibis genus Rhynchaeites, Rhynchaeites mcfaddeni n. sp. lacks the dense pitting of the bill tip associated with abundant Herbst corpuscles, which is developed in extant ibises. However, the new species differs from all stem and crown ibises in possessing a sharply tapering beak tip, which suggests a unique mode of foraging, possibly including prying mollusks from their shells. Given that Rhynchaeites messelensis Wittich, 1898 is one of the most common birds in the prolific Messel deposits but Rhynchaeites mcfaddeni n. sp. is represented by a single specimen after more than 50 years of intense collecting in the Green River Formation, it is likely the two species had divergent foraging strategies, with the former perhaps feeding closer to the lake margin and the latter in streams.

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The fossil record of medusozoan cnidarians is relatively sparse and, in some cases, contentious. Here, we describe a new genus and species of a well-preserved, soft-bodied, tubicolous polyp, Paleocanna tentaculum n. gen. n. sp., from the Upper Ordovician (Katian) Neuville Formation in Québec. These fossils, preserved as carbonaceous compressions, were found in association with typical shelly assemblages. Fifteen slabs of shaly limestone containing ~ 135 specimens of Paleocanna tentaculum n. gen. n. sp. were examined. Individual polyps occupied upright tubes, which occur either solitarily or in clusters. Some tubes exhibit a striated periderm near their base. The polyp is elongated, with a rounded aboral end and a consistent ring of tentacles protruding distally from the tube. A phylogenetic analysis of 69 taxa and 236 discrete morphological characters indicated that the species is more closely related to the extant crown group than it is to the other stem-group medusozoans, e.g., conulariids and carinachitids. The uniform orientation of specimens on single slabs suggests rapid burial. Paleocanna tentaculum n. gen. n. sp. represents an exceptionally preserved member of an Ordovician deposit exhibiting Burgess Shale-type soft-tissue preservation.

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The lower Cambrian Cranbrook Burgess Shale-type Lagerstätte (Series 2, Stage 4) occurs within the Eager Formation of southeastern British Columbia, Canada. This deposit consists of claystone intercalated with normally graded mudstone, which has medium silt to very fine-grained sand and disarticulated skeletal debris near the bed bases, recording mostly accumulation from turbidity currents. Well known for its olenelloid trilobites in particular, the site also contains rare soft-bodied fossils, including Tuzoia carapaces and Anomalocaris claws, and low-diversity and low-density suites of ichnofossils. A 2015 systematic field investigation of a 2.65 m interval recovered 12 ichnotaxa and three types of trace fossils left in open nomenclature. The most abundant are Helminthoidichnites tenuis Fitch, 1850, Palaeophycus tubularis Hall, 1847, Diplocraterion isp., and finger-like structures (FLS). These trace fossils form two ichnocoenoses recurring through the studied interval: (1) the Helminthoidichnites tenuis ichnocoenosis, consisting of small trails and shallow burrows, and (2) the Diplocraterion isp. ichnocoenosis, consisting of paucispecific suites of U-shaped burrows, commonly associated with FLS. The FLS contain a diverse range of disarticulated or broken trilobite sclerites and grains coarser than the host sediment and are interpreted as passively infilled burrows, suggesting significant sediment bypass and trapping of transported grains. Overall, the Cranbrook ichnocoenoses do not display a well-defined tiering structure. The trace fossils overall record the activities of a surficial epifauna and a shallow-tier infauna that colonized the sea bottoms during short windows between episodic flows and inhabited dysoxic (Helminthodichnites tenuis ichnocoenosis) to relatively well-oxygenated (Diplocraterion isp. ichnocoenosis) outer shelf environments.

A single shell of brachiopod Porambonites wesenbergensis Teichert, 1930 is encrusted in several places with thin sheets of Rothpletzella, tentatively assigned to R. gotlandica Wood, 1948, which are preserved as pyritized molds. The spheroidal shape of the pyrite is rare, as is its apparent nucleation on the calcitic walls of Rothplezella. Presumably, its calcareous sheaths were coated with organic films that provided substrate for heterogeneous nucleation. Comparable wall-directed nucleation was documented in the Ediacaran Conotubus, where pyritization initiates on the tube walls and progresses inward. The same brachiopod is also heavily encrusted by craniids and bryozoans. It is unclear whether the brachiopod P. wesenbergensis was encrusted postmortem or during its life.

A recently discovered site in southern Mississippi considered early Arikareean based on identified mammals represents the first of this age from the Gulf Coastal Plain outside of Florida. The Jones Branch Local Fauna was recovered from deltaic/estuarine deposits low in the Catahoula Formation resting unconformably on marl/clay beds of the subjacent, upper Rupelian (lower Oligocene), marine Paynes Hammock Formation. In addition to well-preserved plant material plus reptiles, amphibians, and fishes, the mammals are represented primarily by species previously known almost exclusively from the Great Plains, the northern Rocky Mountains (Montana), and/or John Day region, Oregon, with only a few apparently endemic to the Gulf Coastal Plain. Genera representative of the former include the proscalopid Mesoscalops, the sciurid Hesperopetes, the aplodontiid Downsimus, the putative early castoroid Eutypomys, the castorid Microtheriomys, the eomyids Apeomys and Leptodontomys, the florentiamyid Kirkomys, the mustelids Corumictis and Promartes, the tapir Protapirus, the leptochoerid Leptochoerus, the anthracothere Elomeryx, and the hornless ruminants Hypertragulus and ?Leptomeryx. Mesoscalops, Downsimus, and Apeomys are represented by new species. Additionally, a new genus and species of lagomorph is described, Oligolagus welleri, as is a new genus and new species of eomyid, Paraktioeomys palmeri. Known from both regions is the marsupial Herpetotherium, an apatemyid provisionally referred to Sinclairella, and the borophagine Phlaocyon. Gulf Coastal Plain endemics include the protoceratid Prosynthetoceras orthrionanus and apparently Oligolagus n. gen. and Paraktioeomys n. gen. The geographically broadly distributed horse Miohippus, rhinoceros Diceratherium, and giant entelodont Daeodon are also present. Marine mammals are represented by the dugong Crenatosiren olseni and the odontocete Agorophius pygmaeus. Additionally noted are two taxa from stratigraphically lower formations that are not part of the Jones Branch LF. These include a large species of the entelodont Archaeotherium and the anthracothere Elomeryx armatus, both of which were previously unknown along the Gulf Coastal Plain. The long recognized biotic disparity between the Midcontinent and Gulf Coastal Plain by the early Miocene was not yet strongly apparent during the early to middle Oligocene.

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Early Paleozoic trilobites from the Umachiri Inlier of the Peruvian Altiplano, ~ 100 km northwest of Lake Titicaca, comprise two assemblages, one Cambrian and the other Ordovician. The former assemblage comes from the arkosic upper member of the recently defined Llallahue Formation and represents the oldest record of Cambrian trilobites in the Central Andean Basin. The assemblage consists of transported sclerites of aphelaspidids (Aphelaspis sp. indet. 1; Aphelaspididae gen. indet. sp. indet.) and indeterminable parabolinoidids, indicative of a Paibian–early Jiangshanian (= early Furongian) age. The Ordovician trilobites come from the lower Cunahuiri Member of the overlying Umachiri Formation and include some widespread taxa (Neseuretus Hicks, 1873; Annamitella Mansuy, 1920) that are scarcely geographically diagnostic, plus an asaphid species—Suriaspis? cf. Suriaspis trumpyi (Harrington and Kay, 1951)—that is closely related to material previously described in the Early Ordovician of Colombia. Despite the low diversity of both trilobite assemblages, the Cambrian record is comparable to early Furongian cosmopolitan taxa described primarily in Gondwana (Antarctica), Laurentia, and other regions. The scarce Ordovician specimens, recorded from siltstones and conglomerates, include forms that are more clearly Gondwanan to peri-Gondwanan. These new Cambrian and Ordovician Central Andean Basin assemblages on the Arequipa Terrane belong to separate tectonostratigraphic environments separated by a regional unconformity. The Cambrian assemblage has some affinities to Antarctic taxa that can be explained by the existence of wide back-arc basins along a continuous Terra Australis margin of Gondwana that contributed to effective dispersal of cosmopolitan taxa; in contrast, the Ordovician basin was more restricted and contained trilobites that were endemic to western Gondwana, which is consistent with brachiopod taxa reported from the same Ordovician strata.

Hypoponera Santschi, 1938 is a genus of ponerine ants, well known for its simplified morphology, lacking any clear autopomorphy, and its cosmopolitan distribution. Here, we describe the first Hypoponera in Dominican amber. The discovery of Hypoponera electrocacica new species confirms the long-expected presence of the genus in the Caribbean Miocene. The modern diversity of Hypoponera in the Greater Antilles now stands at five species and two putative subspecies.

UUID: https://zoobank.org/685e8727-72e2-4723-bce3-5d7c53680eee

Coal balls are our primary source of information about Pennsylvanian tropical peat swamps. They capture plant community composition and the complex ecological interactions between coeval terrestrial arthropods and plants. A small number of borings (or feeding tunnels) have been documented in permineralized and compression fossils from the Carboniferous Period. We report two borings filled with coprolites (fecal material) in a coal ball originating from the Mt. Rorah Coal Member (Tradewater Formation; Middle Pennsylvanian of Illinois, USA). Peels of the coal ball were prepared using the cellulose acetate peel method and digitized with a Zeiss Axio Zoom V16 microscope. The borings, measuring 3 cm and 6 cm in length, follow the transverse margin of Psaronius roots and are filled with two distinct types of uniformly shaped coprolites: type 1, ranging from 0.5–2 mm in diameter, and type 2, <60 μm in diameter. Both coprolite types consist of digested Psaronius root tissue and only occur in borings, with no signs of feeding damage observed in the surrounding plant tissues along the margins of the borings or the peel. The dimensions of the borings and morphology of type 1 coprolites suggest they were made by an early roachoid, millipede, or another terrestrial arthropod group. The distribution and content of type 2 coprolites indicate coprophagy, or secondary feeding on type 1 coprolites, likely by oribatid mites. These borings provide new insight into the life history of the organisms that created these tunnels, their role in litter decomposition, and the food webs of Pennsylvanian peat swamps.