The study of Ordovician ostracods from eastern North America has been neglected for more than 40 years, prompting the need for taxonomic updates. Newly acquired silicified materials from the Late Ordovician Crown Point Formation of Valcour Island, northeastern New York State, are here systematically described. Fifty-two species of 42 genera are identified, including three new species: Vogdesella longidorsa n. sp., Eokloedenella duodepressa n. sp. and Aviacypris valcourensis n. sp. The combination of high diversity and dominance of both beyrichiocopids and podocopids indicates that the Valcour fauna existed in a stable, shallow-water carbonate environment. Biostratigraphical evidence supports an early Sandbian age designation for the Crown Point Formation. Comparison of the Valcour fauna with others in Laurentia as well as from adjacent paleocontinents shows shared composition at the genus level, especially with Baltica, but high endemicity at the species level. This suggests a history of frequent faunal exchange with a fast speciation rate during the early Late Ordovician in the southern region of Laurentia.

UUID: http://zoobank.org/e12dc8ce-0b2a-4f9d-aca2-bf3e298d9635

A new species of dissorophoid temnospondyl, Melanerpeton kuselense new species, is reported from the Remigiusberg Formation (Carboniferous-Permian boundary) of southwestern Germany. The type and only known specimen is a skull belonging to a moderately advanced larva with distinctive features: (1) a very slender postorbital skull table, (2) large nasal, (3) short squamosal giving a short gape, and (4) a gracile and extremely small pterygoid. Phylogenetic analysis finds it to fall well within the branchiosaurids, above the Pennsylvanian Branchiosaurinae, and sister taxon to Melanerpeton pusillum Fritsch, 1878 from lower Permian deposits of the Czech Republic. It is not closely related to any of the branchiosaurids from the Saar-Nahe Basin, adding to the distinctive Remigiusberg tetrapod faunal assemblage.

UUID: http://zoobank.org/52c398e1-78be-45db-b2e0-988fc3c1af77

Cambrian faunas of the Grand Canyon are neither diverse nor abundant, and several historical collections seem to have mixed taxa from several biozones. As a result, fine-scale reinterpretation of Grand Canyon biostratigraphy and broader-scale correlation of the Tonto Group and its fossils have been hampered by the lack of definitive and refined biostratigraphic indicators. Here we report new fossil occurrences from the Tonto Group, including from units that previously lacked biomineralized fossils, such as the Frenchman Mountain Dolostone. When integrated with historic collections, our data indicate that the Tonto Group ranges from the upper Dyeran to lowermost Steptoean Laurentian stages (global upper Series 2, Stage 4 to basal Furongian Series, Paibian Stage). Trilobite assemblages span the upper Dyeran (Peachella iddingsi Biozone) to lower Marjuman (Bolaspidella Biozone) stages and are distributed from the uppermost Tapeats Sandstone to lowermost Frenchman Mountain Dolostone.

Based on lithologic and paleontological data, three disconformities occur within the Cambrian of the Grand Canyon: (1) between the Dyeran and Delamaran stages in the uppermost Tapeats to lowermost Bright Angel Formation, (2) within the Delamaran Stage within the Bright Angel Formation, and (3) between the Delamaran and Topazan stages, higher in the Bright Angel Formation.

Cambrian trilobites from the Tonto Group consist of seven olenelloid, 17 corynexochid, and 33 ptychoparioid species, as well as 10 taxa that are not identifiable at generic or higher levels. New species include Kootenia barensis and Albertella nebeli. Some taxa are new to the Grand Canyon region, although they are known from the Great Basin (Nevada, California), southern Arizona, Montana, and Canada. These taxa include olenellids: Mesonacis fremonti (Walcott), Olenellus gilberti Meek in White, Olenellus terminatus Palmer, and Olenellus cf. O. fowleri Palmer; corynexochids: Anoria? bessus (Walcott), Caspimexis cf. C. radiatus (Palmer in Palmer and Halley), Kootenia aff. K. granulospinosa Palmer, 1968, and Zacanthoides cf. Z. typicalis (Walcott); and ptychopariids: Amecephalus cf. Am. normale (Resser), Am. piochensis (Walcott), Am. scapegoatensis (Deiss), Crepicephalus? upis Walcott, Ehmania weedi Resser, Eldoradia cf. E. prospectensis (Walcott), Glyphaspis tetonensis Resser, Kochina vestita Resser, Mexicella cf. Me. robusta Sundberg and McCollum, Mexicella mexicana Lochman, Modocia sp. indet., Solenopleurella? quadrata Rasetti, Trachycheilus granulosus Sundberg, and Tr. whirlwindensis Sundberg. Type specimens of Solenopleurella erosa Resser was divided into two species: the pygidia are assigned to Kootenia erosa (Resser) new combination, and the much smaller cranidia are assigned to Spencella? sp. indet.

UUID: http://zoobank.org/f3034b33-00d1-4d00-a9d5-0a73f7a330d2

In this study, we present a revised interpretation of mayfly larval body impressions previously described from the fluvial Wapiti Formation of Alberta, Canada. Unlike typical insect fossils that occur in lacustrine deposits or amber inclusions, these fossils are interpreted to have been preserved in a depositional setting characterized by currents rapid enough to erode and transport fine-grained sand. To determine how the fossils were formed, we examined the spatial relationship between the fossils and associated tool marks preserved on the same bedding surface. All 16 of the fossil specimens analyzed were in life orientation with their heads directed upstream, suggesting that the impressions were produced by live organisms. Here we propose a new ichnotaxon Kalyptichnus belli n. igen. n. isp. for shallow self-burial traces of insect larvae.

UUID: https://zoobank.org/eade3ae6-2e98-4f97-ac17-2577fc562000

Cambrian tidal flat deposits of the Elk Mound Group at Blackberry Hill, Wisconsin, USA, provide some of the earliest body fossils of euthycarcinoids, phyllocarids, and scyphozoans. Also, some of the earliest evidence of animal activities on land, alongside a diverse ichnofauna, have been observed. Here we expand the ichnotaxonomic diversity of that site, emend the diagnosis of Protichnites, discuss the recent reinterpretation of Protichnites eremita, and establish Seilacherichnus new ichnogenus and Climactichnites blackberriensis new ichnospecies. What may be the first fossil evidence of an animal feeding on a scyphozoan at Blackberry Hill or equivalent Cambrian tidal flats is reported. Ichnotaxa not previously illustrated or described from Blackberry Hill include Siskemia isp., Diplopodichnus isp., Stiallia pilosa, and Cochlichnus? isp. This expansion of the ichnotaxonomic diversity observed in the Blackberry Hill strata further illustrates the early exploitation of tidal flats.

UUID: http://zoobank.org/f8c5d0a5-aa4d-4eb3-87dd-9bf44b4af8c3.

This study describes the Serkinskaya faunal complex of the Siberian lower Cambrian Kessyusa Group, which includes a fragment of gnathobase, several scalids of priapulid-like organisms, various morphotypes of spines, organic films with outgrowths, and other organic remains. Organic microfossils that we identified as gnathobase fragments (a jaw-like fragment and a robust spine with porous structure) were studied via Raman spectroscopy, and phase distribution maps were constructed to identify different kerogens. The jaw-like fragment has heterogeneity on the surface of the microfossil and can be interpreted as reflecting differential preservation of two different layers of the cuticle. The age of these remains is estimated to be Cambrian Fortunian to Stage 2 (Vendian–Cambrian, possibly Tommotian), which makes the identification of gnathobase fragments one of the oldest known occurrences of evidence for durophagy. These findings confirm the presence of filter-feeding, deposit-feeding (priapulids), vertical mixing of the sediment in the first centimeter, predation pressure (cuticle with outgrowths), and possible durophagy in the earliest Cambrian.

The Ediacaran–Cambrian boundary, representing one of Earth’s most critical transitions, is currently defined by the Fortune Head (Newfoundland, Canada) GSSP (Global Standard Stratotype Section and Point) at a point once regarded as the first appearance of the branching trace fossil Treptichnus pedum. However, T. pedum has subsequently been found below the GSSP, and its global distribution is primarily restricted to siliciclastic facies where application of alternative biostratigraphic and chemostratigraphic correlation tools is challenging. Investigations of acanthomorphic acritarchs in basal Cambrian strata of South China suggest that these microfossils could provide a robust complementary biostratigraphic marker for the Ediacaran–Cambrian boundary. Acanthomorphic acritarchs are widely distributed across the Yangtze Platform in chert–phosphorite layers intercalated with carbonates and shales, thereby allowing their biostratigraphic occurrences to be calibrated with small shelly fossil biozones and carbon isotope data.

Here, the earliest Cambrian Asteridium–Heliosphaeridium–Comasphaeridium (AHC) assemblage biozone is identified at 11 localities within the Yanjiahe, lower Niutitang, and upper Liuchapo formations, representing diverse depositional environments. Two latest Ediacaran microfossils, both characterized by uniserially chained modules and representing a characteristic Ediacaran assemblage (the Horodyskia minor–Nenoxites jiumenensis, or HmNj, assemblage biozone), are also identified in the Liuchapo Formation, but do not overlap with the Cambrian AHC acritarch biozone. The AHC assemblage biozone is demonstrated to be stratigraphically equivalent to basal Cambrian small shelly fossils and a negative δ13C isotope excursion known to occur at the Ediacaran–Cambrian boundary. Thus, in South China, the AHC and HmNj assemblage biozones can be used to effectively and reliably constrain the Ediacaran–Cambrian boundary.

UUID: http://zoobank.org/2fd52705-f7ef-4276-897e-10e89efb04ad

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

This study considers Glomalveolina subtilis Hottinger, 1960, to be a distinct species within the genus Glomalveolina, previously grouped with G. lepidula (Schwager, 1883). This species is distinguished by unique morphological and biometrical features, setting it apart from closely related species and establishing it as a significant biostratigraphic marker for the early Ypresian (SBZ6-7) in the central Neo-Tethys. Although first reported from the Iranian platform, it expands the paleobiogeographic distribution of G. subtilis, with earlier records from the western Neo-Tethys (Mediterranean and North African basins) during the early Ilerdian (SBZ5–SBZ6) and from the eastern Neo-Tethys (China) in the middle Ilerdian (SBZ7–SBZ8). The Alveolina biostratigraphy is correlated with the calcareous nannofossil biostratigraphy, placing it in the middle part of the NP10 Zone. This discovery highlights the broader distribution of G. subtilis and its significance in refining biostratigraphic correlations and understanding foraminiferal evolution during the Paleocene–Eocene transition.

Ecological live–live interactions in fossil invertebrates, although providing valuable information about the past environment and ecology, are still underexplored. Trematode parasites have a complex life cycle, often utilizing mollusks as their intermediate hosts. However, since the trematodes themselves lack a rigid skeleton, these interactions can be detected only when there is anomalous growth in the shell, the sole preserved part of the mollusk. When malformations produced by the host are preserved, it may be concluded that the mollusk was alive at the time of interaction. This study aims to assess the evidence of different ecological interactions preserved in the shells of Zidona dufresnii (Donovan, 1823) and determine which were results of a life-to-life relationship, as well as which organisms were involved in that interaction. A total of 894 shells collected from Quaternary deposits in southern Brazil were analyzed regarding the presence and morphology of bioerosions and malformations. As a result, 10 ichnogenera of bioerosion traces were identified. In addition, seven types of malformations were observed. These include pits and igloo-like structures, which are results of infestation by parasitic trematodes. Blister and sheet forms indicate response to the presence of spionid species that perforated the shell. Verrucose malformations, we suggest here, are also indicative of trematode infestation. ¹⁴C dating shows that the gastropod shells are derived from both Holocene and Late Pleistocene deposits, indicating significant time averaging. While evidence of life–life interaction is more common in Holocene shells, Pleistocene shells display a greater prevalence of bioerosion traces.

The Bennettitales, a group of extinct gymnosperms, had outstanding species diversity throughout the Mesozoic and were abundant during the Jurassic. They were key components of terrestrial ecosystems, thriving in diverse climates and environmental conditions. However, a deeper understanding of the ecological strategies exhibited by this extinct lineage across time and space within a well-characterized geological context is still lacking for the region. Here, we examine bennettitalean assemblages from the Middle Jurassic Otlaltepec Formation (Otlaltepec Basin) and compare them with floras from two other rift basins (Tlaxiaco and Ayuquila) in low latitudes. Based on morphological features, we propose the new species Zamites ambigua, and identify the following additional taxa: Zamites lucerensis, Zamites oaxacensis, Zamites tribulosus, cf. Zamites diquiyui, Zamites sp. 1, Zamites sp. 2, Bennettitcarpus sp. 1, Bennettitcarpus sp. 2, and cf. Weltrichia xochitetlii, along with two types of gymnosperm foliage of uncertain affinities.

Our findings on bennettitalean diversity in the Otlaltepec Formation reveal the presence of foliage across all three basins in both time and space, indicating a generalist element among these rift environments. In contrast, other foliage and reproductive structures exhibit two distinct distributional patterns: some are confined to a single basin over time, while others appear only during specific intervals in each basin’s history. Our findings highlight that some Bennettitales exhibited ecological resilience, maintaining their morphology and distribution despite the shifting environmental conditions caused by tectonic activity. This suggests that certain generalist taxa persisted across varying moisture regimes and depositional settings, while others displayed more localized or temporally restricted distributions.

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 crown clade including Staurozoa, Cubozoa, Scyphozoa than to other fossil 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.

UUID: http://zoobank.org/12d03d82-1925-4578-873e-2e9c23db635f

The rhynchonellide brachiopod Altaethyrella Severgina, 1978 is a key component of the shallow-water Altaethyrella brachiopod fauna that flourished in the tropical Proto-Tethys during the Katian (Late Ordovician). This study describes an unusually small species of the genus, Altaethyrella xuejiaoi new species, from the lower Katian (Ka-1) Yingan Formation in northwestern Tarim, Xinjiang, Northwest China. With an average length of 8.60 mm, width of 9.73 mm, and depth of 5.69 mm, it is approximately two-fifths the size of typical Altaethyrella species, although the presence of a central myophragm in the dorsal cavity and well-developed teeth confirms that the specimens of the new species are mature and not simply juvenile forms. This species inhabited the shallow-water reef-stromatoporoid bioherm, providing new insights into the origination and early evolution of the rhynchonellides. Furthermore, this study contributes new generic occurrence data that will improve our understanding of the paleogeographic distribution of the Altaethyrella fauna prior to the Late Ordovician Mass Extinction (LOME).

UUID: http://zoobank.org/f3f5959a-7d6d-4554-914c-585658e3eca8

Protopalpares lindgrenae new genus new species (Neuroptera: Myrmeleontidae) is described from the Fossil Butte Member of the early Eocene Green River Formation (Wyoming, USA). This is the first Neuroptera species from the Fossil Butte Member, and the first fossil Palparinae. It is assigned to this subfamily based on the synapomorphy proposed here that the forewing posterior branch of RP1 and the stem of MP+CuA1 curve toward each other and are connected by two aligned crossveins at their closest. The venation of Protopalpares is most similar within the family to that of the Early Cretaceous Palaeonleontidae, indicating that Palparinae and Palaeonleontidae are likely closely related.

UUID: http://zoobank.org/fc4c124c-eb4b-432e-833c-cde7e595f653

Thylacocephalans are a peculiar group of fossil pancrustaceans characterized by a shield enveloping most of the body, large compound eyes, three pairs of raptorial appendages, eight pairs of gills, and a posterior trunk consisting of 8–22 segments. With a fossil record spanning the Silurian to Cretaceous, thylacocephalans have a wide distribution, both in time and space. However, there has been limited examination of specimens from different time periods, and, as such, thylacocephalan systematics remains controversial, preventing a detailed study on their evolution and diversification. One period that requires further study is the Carboniferous. Almost all known Carboniferous thylacocephalans originate from the USA, including Concavicaris—the most iconic Paleozoic thylacocephalan taxon, which has functioned as a wastebasket genus. Further, there are several Carboniferous thylacocephalan occurrences mentioned in the literature from the USA that have not formally been described. To have a more detailed understanding of Carboniferous thylacocephalan diversity dynamics, as well as underlying evolutionary processes, a thorough systematic review is needed. To rectify this, we performed a detailed review of Carboniferous Concavicaris from the USA. In doing so, we describe a new genus and species, Triangulusinus pustulosus n. gen. n. sp., and present a detailed revision of Concavicaris—a taxon that we split into Concavicaris sensu stricto, Paraconcavicaris, Quadrangulucaris n. gen., and Rotundaparma n. gen. This revision opens new perspectives on the systematics and diversification of thylacocephalans.

UUID: http://zoobank.org/3371e3b9-3b57-4df1-897e-37cc8be201ce

Upper Middle Devonian to lowermost Upper Devonian brachiopods from Mount Józefka near Górno (Holy Cross Mountains, Poland) are described from the Laskowa Góra Beds (mostly top-Givetian dengleri Conodont Biozone) and Szydłówek Beds (Givetian–Frasnian transition). Twenty species are present, whereof two new ones. Glosshypothyridina theophili new species is larger and has a less angular hinge margin than G. procuboides (Kayser, 1871). Data on internal features of Hypothyridina Buckman, 1906, Glosshypothyridina Rzhonsnitskaya, 1978, and Tullhypothyridina Sartenaer, 2003 are summarized on the basis of published and unpublished sources, allowing rectification of previous incorrect interpretations of these genera. Kyrtatrypa stanislai new species resembles middle Givetian K. pauli Halamski and Baliński in Halamski et al., 2024, but possesses rudimentary dental nuclei. Similar (previously unnoticed) minute dental nuclei occur in the type species K. culminigera (Struve, 1966), so the diagnosis of Kyrtatrypa Struve, 1966 is emended. The moderately diverse fauna thrived in biogenic and muddy niches within and around perireefal coral thickets in the protected ramp-slope of the northern Kielce carbonate platform. The at-most modest replacement of brachiopod faunas between the middle Givetian and the early Frasnian times during the post-Taghanic ecosystem recovery is confirmed for the Euramerican shelf. However, a different response to global stresses is evident for the sessile benthos across the Middle–Upper Devonian boundary in the intrashelf basin and the stromatoporoid-coral bank settings. Off-reef communities were more resilient, affected by extinction probably half as much as the more sensitive reef-related faunas. The ecological-evolutionary stasis among bottom-level shelly benthos contrasts with the extinction of the Hamilton/upper Tully fauna in the Appalachian Basin, the type area of the Taghanic Crisis.

UUID: http://zoobank.org/6a3a18da-d56d-4d98-a548-ebd37c58f832

Numerous oligochaete cocoons, previously interpreted as cladoceran crustaceans, are described from the upper Permian (Lopingian) freshwater Karaungir Lagerstätte in eastern Kazakhstan. The cocoons appear as small, wrinkled, ovoid capsules, prolonged into a neck at one pole and a long slender stalk at the other; both extensions are covered with minute ridges forming a striated pattern. By their size range and distinct (although limited) morphological features, the cocoons are identical to those of the extant freshwater genus Rhynchelmis Hoffmeister, 1843 (Oligochaeta: Lumbriculidae) and thus represent the oldest undoubted record of the Clitellata. We interpret Archedaphnia Smirnov, 1970 (= Propleuroxus Smirnov, 1970, n. syn.) as a genus for fossil microdrile oligochaete cocoons similar to those of Rhynchelmis, and synonymize all five species described in Archedaphnia and Propleuroxus under Archedaphnia kazakhstanica Smirnov, 1970 sensu lato.

Angustothyrididae Dagys, 1972 is a key group of terebratulide brachiopods, because it exhibits characteristics bridging the two major suborders, Terebratulidina and Terebratellidina, and could represent an evolutionary link between them. However, the taxonomy of its type genus, Angustothyris Dagys, 1972, has remained poorly understood. Our restudy of specimens from the Middle Triassic of Hungary and southwestern China, including material from the type localities, reveals that the specimens previously assigned to Angustothyris actually represent multiple genera. This indicates that the diversity of this group has been underestimated, leading us to establish Balatonithyris new genus, Qianothyris new genus, and Angustothyris aszofoensis new species. The long teloform loop in Qianothyris n. gen. fills a morphological gap between short-looped terebratulidines and long-looped terebratellidines, supporting a Late Permian–Triassic origin of the terebratellidines from the Angustothyrididae. The morphological evidence, however, conflicts with molecular data that suggest an earlier divergence between the two suborders. This contradiction implies that either the Angustothyrididae is not the direct ancestor of terebratellidines, or that the terebratellidines are a polyphyletic group with multiple evolutionary origins.

UUID: http://zoobank.org/b19352c0-8352-4bba-a0b1-a95963f3da38