2023 in paleontology


Flora

"Algae"
 A study on the fossil material of rhodolith-forming coralline red algae from the Miocene Long Formation from the Little Andaman (India), interpreted as indicative of high carbonate production in the northeastern Indian Ocean during the Serravallian, is published by Dey et al. (2023). Plants

Fungi

Mycological research
 New information on the anatomy of Sporocarpon asteroides, inferred from new specimens from the Lower Coal Measures (United Kingdom), is presented by Krings et al. (2023), who interpret S. asteroides as a unisporic sporocarp with a parenchyma-like peridium, probably with affinities to the Glomeromycota. The first finding of a mycelium of a putative nematophagous fungus belonging to the group Basidiomycota from the Cretaceous of North Asia is reported from the Santonian Yantardakh Lagerstätte (Taymyr, Russia) by Sukhomlyn & Perkovsky (2023). Kutchiathyrites eccentricus is transferred to the modern genus Mycoenterolobium by Worobiec, Worobiec & Liu (2023) on the basis of study of the fossil material from the Neogene deposits of the Gray Fossil Site (Tennessee, United States) and the Bełchatów Lignite Mine (Poland). General floral research

Cnidarians

New cnidarian taxa

Cnidarian research
 Pywackia baileyi, originally classified as a bryozoan, is reinterpreted as a cnidarian by Hageman & Vinn (2023). Conulariid specimens preserved with muscle bundles and a possible gastric cavity are described from the Carboniferous Wewoka and Graham formations (Oklahoma and Texas, United States) by Sendino et al. (2023). Van Iten et al. (2023) describe soft parts of two specimens of Metaconularia manni from the Silurian (Sheinwoodian) Scotch Grove Formation (Iowa, United States), and interpret their anatomy as indicating that at least one species of conulariid might have lacked a free-living, medusoid life phase, and might have produced eggs and sperm within the body of the sessile polyp. Redescription of Conicula striata is published by Zhao et al. (2023), who report that C. striata had features of both anthozoans and medusozoan polyps, and recover it as a stem-medusozoan, potentially indicating that medusozoans had an anemone-like ancestor. Zhang et al. (2023) describe new fossil material of Qinscyphus necopinus from the Cambrian (Fortunian) Kuanchuanpu Formation (China),  including the whole apical part and providing complete information on the morphology of Qinscyphus. Plotnick, Young & Hagadorn (2023) classify Essexella asherae as a sea anemone, and reinterpret Reticulomedusa greenei as the pedal or oral disc of E. asherae. Arthropods

Bryozoans

New bryozoan taxa

Bryozoan research
 Yang et al. (2023) reinterpret putative Cambrian bryozoan Protomelission as an early dasycladalean green alga, and conclude that there are no unequivocal bryozoans of Cambrian age. Brachiopods

New brachiopod taxa

Brachiopod research
 A study on the diversification dynamics of brachiopods and bivalves throughout their evolutionary histories is published by Guo et al. (2023), who interpret their findings as indicating that the switch from brachiopods to bivalves as major seabed organisms was unlikely to be caused by competitive exclusion of brachiopods by bivalves, but rather was likely caused by loss of brachiopod diversity in the Permian–Triassic extinction event and by bivalve diversification in the Cretaceous and Cenozoic that wasn't matched by brachiopods. A study on the morphological diversity of lingulid brachiopods throughout the Phanerozoic is published by Liang et al. (2023), who find that Phanerozoic mass extinctions disproportionally wiped out lingulids that were not infaunal, and interpret the limited morphological and ecological diversity of modern lingulids as mainly resulting from differential effects of mass extinctions rather than from deterministic processes such as natural selection. Molluscs

Echinoderms

New echinoderm taxa

Echinoderm research
 Cole, Wright & Thompson (2023) experimentally confirm that ratios of seawater magnesium and calcium have a profound effect on short-term regeneration rates in extant brittle star Ophioderma cinereum, but find no evidence of a significant relationship between changes of seawater magnesium and calcium ratios and long-term changes of echinoderm biodiversity over the past 500 million years. Álvarez-Armada et al. (2023) describe a specimen of Hyperoblastus reimanni preserved with structures interpreted as three larvae and a gonad, and interpret this finding as indicative of the presence of sexual dimorphism in blastoids, as well as of early evolution of internal brooding of larvae in this group. A study on the evolution of plate systems in the calyx of crinoids, based on data from early crinoids from Tremadocian, is published by Guensburg, Mooi & Mongiardino Koch (2023). A study on the ontogeny of Erisocrinus typus, based on data from fossil material representing a growth series from the Carboniferous Barnsdall Formation (Oklahoma, United States), is published by Hernandez Gomez et al. (2023). Gorzelak et al. (2023) report the presence of microstructure similar to the diamond-type triply periodic minimal surfaces in the skeleton of a specimen of Haplocrinites from Devonian, similar to microstructure reported in extant Protoreaster nodosus, and representing the oldest record of such microstructure in echinoderms reported to date. The oldest fossil material of members of the genus Percevalicrinus reported to date is described from the Lower Jurassic deposits in the western Saharan Atlas (Algeria) by Salamon et al. (2023). Kolata et al. (2023) report the discovery of new specimens of Cyclocystoides scammaphoris from the Ordovician Platteville Formation (Illinois), Plattin and Decorah groups (Missouri) and Lebanon Limestone (Tennessee), providing new information on the anatomy of this cyclocystoid. Evidence from deep-sea sediment samples interpreted as indicative of continuous record of deep-sea Atelostomata dating back to the Early Cretaceous is presented by Wiese et al. (2023). The youngest stenuroid asterozoan specimen reported to date is described from the Permian (Wordian-Capitanian) Las Delicias Formation (Mexico) by Sour-Tovar, Quiroz-Barroso & Martín-Medrano (2023). Thuy et al. (2023) report the discovery of an assemblage of brittle star microfossils from Carboniferous deep-water sediments of Oklahoma (United States), including fossils of basal representatives of Amphilepidida and Ophioscolecida, and interpret this finding as indicating that a significant part of the early diversification of the brittle star crown group might have taken place in deep-water settings. Hemichordates

Hemichordate research
 Nanglu et al. (2023) report the discovery of an orthocone cephalopod phragmocone from the Ordovician Fezouata Formation (Morocco) which was extensively populated by rhabdopleurid-like epibionts after the death of the cephalopod, providing evidence of the use of mollusc shells as hard substrates by hemichordates dating back nearly 480 million years ago. Lopez et al. (2023) describe graptolite fossil material from the Silurian Rinconada Formation (Argentina), representing the first Pridolian graptolite assemblage from South America reported to date, and possibly providing evidence of faunal recovery interval after the Kozlowskii-Lau Event. Conodonts

New conodont taxa

Conodont research
 A study on the size-frequency distribution of the P1 elements of members of the genera Palmatolepis, Ancyrodella and Polygnathus during the late Frasnian and the Famennian is published by Girard et al. (2023), who don't confirm the temperature-size rule as a general rule explaining size variation in the studied fossils. Wu et al. (2023) report the discovery of an abundant conodont community in the Lower Triassic strata in the Zhangjiawan stratigraphic succession (Yuan'an County, Hubei, China), and interpret this finding as suggesting that the studied area might have been a refuge area for the Early Triassic conodont communities and marine ecosystem in general, as other Lower Triassic strata nearby yield only rare conodonts. Evidence indicating that co-occurring Late Triassic conodonts Metapolygnathus communisti and Epigondolella rigoi differed in their diets is presented by Kelz et al. (2023). A study on the diversity and biostratigraphy of late Norian conodont faunas from the Dashuitang and Nanshuba formations in the Baoshan area (Yunnan, China) is published by Zeng et al. (2023), who report evidence of a decline of conodont diversity during the late Norian, interpreted by the authors as the first crisis of the protracted suite of end-Triassic conodont extinctions. Evidence from the Kastuyama section in the Inuyama area in Honshu (Japan), argued to be indicative of the survival of the conodont species Misikella posthernsteini into the Early Jurassic, is presented by Du et al. (2023). Fish

Amphibians

New amphibian taxa

Amphibian research
 New reconstruction of the skull of Crassigyrinus scoticus is presented by Porro, Rayfield & Clack (2023). Pardo (2023) redescribes the anatomy of the neurocranium of Archeria crassidisca, based on data from a previously unreported partial braincase, and interprets embolomeres as more likely to be stem-tetrapods than stem-amniotes. A study on the morphology and ossification sequences of carpus and tarsus in basal stereospondylomorphs, providing evidence of variability in the development of the mesopodium, is published by Witzmann & Fröbisch (2023). Groenewald et al. (2023) describe body impressions and associated swim trails of rhinesuchid temnospondyls from the Permian Karoo Basin (South Africa), providing evidence that rhinesuchids used their tails for propulsion and held their legs tucked in next to the body while swimming. A study comparing the probable maximum sizes that could be reached by specimens belonging to the Early Triassic temnospondyl taxa from Eastern Europe is published by Morkovin (2023), who reports the discovery of an unusually large lower jaw of Vladlenosaurus alexeyevi from the Skoba locality (Komi Republic, Russia), and argues that the size differences characteristic of the standard adult states of the studied temnospondyl taxa were likely reduced in individuals belonging to very late age categories. New information on the anatomy of Mastodonsaurus cappelensis is presented by Schoch et al. (2023), who report the presence of anatomical differences between M. cappelensis and the stratigraphically younger M. giganteus, indicating that the latter species adapted to feed on a wider range of prey. A study on the histology of large temnospondyl humeri from the Late Triassic Krasiejów site (Poland) is published by Teschner et al. (2023), who report that the humeri of Cyclotosaurus intermedius and Metoposaurus krasiejowensis might show only minor differences in morphology, making histology a valuable tool for taxonomic assignment. A study on the skull morphology of Koskinonodon perfectum, Dutuitosaurus ouazzoui, Metoposaurus diagnosticus and Eocyclotosaurus appetolatus, providing evidence which might be indicative of the presence of sexual dimorphism in the studied taxa, is published by Rinehart & Lucas (2023). Review of the fossil record of the genus Mioproteus in Southeastern Europe is published by Syromyatnikova (2023). Skutschas et al. (2023) describe salamander dentaries from the Lower Cretaceous Teete locality (Batylykh Formation; Sakha, Russia) representing the northernmost record of non-karaurid salamanders in the Mesozoic reported to date. A study on the origin of the unique body plan of frogs, based on data from extant and fossil taxa, is published by Pérez-Ben, Lires & Gómez (2023), who interpret their findings as indicative of early diversification (resulting in diversity of locomotor modes in Jurassic stem frogs) followed by period of reduced morphological diversity and repeated convergent evolution of limb proportions and locomotor capabilities, and do not consider the interpretation of the body plan of frogs as resulting from an adaptation the ancestral frogs to jumping to be strongly supported by the fossil record. Description of the anatomy of the metamorphosing larvae, juveniles and fully grown adults of Genibatrachus is published by Roček, Dong & Wang (2023). The easternmost and the youngest frog remains from the Late Cretaceous of Asia reported to date are described from the Maastrichtian dinosaur locality in the city of Blagoveshchensk (Amur Oblast, Russia) by Skutschas et al. (2023). Vallejo-Pareja et al. (2023) describe the first pre-Quaternary fossils referred to Eleutherodactylus from Florida, and interpret this finding as indicating that by the Late Oligocene Eleutherodactylus was already established in North America before colonizing Central America. Georgalis, Prendini & Roček (2023) describe new fossil material of Thaumastosaurus from the Eocene Quercy Phosphorites Formation (France), and report evidence of diversity of morphotypes in the fossil material of Thaumastosaurus which might be indicative of the presence of cryptic taxa. Lemierre et al. (2023) describe a skeleton of a member of the genus Pelophylax from the lowest Oligocene of Chartres-de-Bretagne (western France), representing one of the oldest occurrences of the genus reported to date. Bazzana-Adams et al. (2023) reconstruct the first virtual cranial endocast of Seymouria. Barták & Ivanov (2023) describe an exceptionally well-preserved specimen of Sauropleura scalaris (including near-complete skull) from the upper Carboniferous deposits of Nýřany (Czech Republic), providing new information on the anatomy and ontogeny of this taxon. Bulanov (2023) reinterprets putative bolosaurid "Bolosaurus" traati as a diadectomorph, transfers it to the genus Stephanospondylus, and considers Ambedus to be a non-diadectomorph tetrapod of uncertain affinities. Reptiles

Synapsids

Non-mammalian synapsids

New synapsid taxa

Synapsid research
 A study on the evolution of the dentary size in non-mammalian synapsids is published by Harano & Asahara (2023), who find evidence indicative of an evolutionary trend for enlargement of dentary relative to the overall lower jaw size across all non-mammalian synapsids, regardless of their relation to mammals, but find no evidence for an evolutionary trend in dentary enlargement at the expense of the postdentary bones. Studies on the evolution of the forelimb and hindlimb musculature of synapsids are published by Bishop & Pierce (2023). A study on the ecomorphology of synapsids throughout their evolutionary history is published by Hellert et al. (2023), who find carnivory to be the ancestral dietary regime of major synapsid radiations, but also find that small body size was established as the common ancestral state of radiations as late as in the Late Triassic, near the origin of Mammaliaformes, and report the presence of derived traits in the ancestors of major synapsid radiations. Calábková et al. (2023) describe tracks assignable to the ichnogenus Dimetropus and produced by "pelycosaur"-grade synapsids from the Permian (Asselian) Padochov and Letovice formations (Boskovice Basin, Czech Republic), including a specimen with preserved skin impressions, and providing new information on the diversity of the earliest Permian equatorial tetrapod faunas. Maho, Bevitt & Reisz (2023) describe fossil material of Varanops brevirostris from the Dolese Brother Limestone Quarry (Oklahoma, United States), confirming the presence of this taxon at Richards Spur, and interpret this finding as indicating that, although less abundant than Cacops and Acheloma, V. brevirostris was not as rare taxon as previously thought. Gônet et al. (2023) present a model which can be used to determine posture from humeral parameters in extant mammals, and use it to infer a sprawling posture for Dimetrodon natalis. Bazzana-Adams, Evans & Reisz (2023) describe the brain and inner ear of Dimetrodon loomisi, and interpret their findings as indicating that Dimetrodon was sensitive to a greater range of frequencies beyond the ultra-low-frequency ground-borne sounds anticipated in previous estimates. Partial humerus of a synapsid of uncertain affinities, with anatomical traits blurring the distinction between the "pelycosaur"-grade synapsids and therapsids, is described from the Permian (Capitanian) Main Karoo Basin (South Africa) by Bishop et al. (2023). An almost complete skull of Pampaphoneus biccai, providing new information on the anatomy of this species, is described from the Permian Rio do Rasto Formation (Brazil) by Santos et al. (2023). Benoit, Norton & Jirah (2023) describe the maxillary canal of Jonkeria truculenta, reporting that is structure shares more similarities with the maxillary canal of the tapinocephalid Moschognathus than with that of Anteosaurus. Rubidge, Day & Benoit (2023) report the first discovery of the fossil material of Colobodectes cluveri from the Grootfontein Member of the Abrahamskraal Formation (South Africa), providing correlation between strata of the Abrahamskraal Formation from the northwestern, western and southwestern part of the Karoo Basin. Laaß & Kaestner (2023) report the presence of a system of turbinal ridges for attachment of respiratory and olfactory turbinates (strongly resembling the mammalian condition) in the skull of Kawingasaurus fossilis, and interpret this finding as supporting a convergent origin of endothermy in dicynodonts, possibly influenced by their fossorial habitat. Sidor, Mann & Angielczyk (2023) report the discovery of the fossil material of the gorgonopsian Gorgonops sp. and the dicynodont Endothiodon sp. from the Permian Madumabisa Mudstone Formation, indicating that the stratigraphic range of vertebrate-bearing horizons in southern Zambia includes not only Guadalupian Tapinocephalus Assemblage Zone-equivalent strata, but also Lopingian Endothiodon Assemblage Zone-age strata. Bendel et al. (2023) describe a nearly complete skeleton of Gorgonops torvus from the Permian Endothiodon Assemblage Zone of the Karoo Basin (South Africa), and interpret the anatomy of the studied specimen as indicating that G. torvus was likely ambush predator, able to chase its prey over short distances. Redescription of the holotype of Nythosaurus larvatus is published by Pusch et al. (2023), who interpret N. larvatus as a taxon distinct from Thrinaxodon liorhinus. Kulik (2023) compares femoral histology of two specimens of Scalenodon angustifrons of the same size, report evidence of skeletal maturity in one of the studied specimens, and interprets her findings as indicative of a flexible growth strategy in S. angustifrons. Hoffmann, de Andrade & Martinelli (2023) redescribe the skeletal anatomy of "Probelesodon" kitchingi, and transfer this species to the genus Chiniquodon. Description of new lower jaw remains of Agudotherium gassenae from the Late Triassic of Brazil, providing new information on the anatomy of this taxon, and a study on its phylogenetic affinities is published by Kerber, Pretto & Müller (2023), who recover A. gassenae as the sister taxon of Prozostrodontia. Stefanello et al. (2023) describe a new, complete and exceptionally well-preserved skull of Prozostrodon brasiliensis from the Upper Triassic strata in Brazil, and name a new endemic clade of South American cynodonts – Prozostrodontidae, including Prozostrodon and Pseudotherium. A study on the endocranial anatomy of Prozostrodon brasiliensis and Therioherpeton cargnini is published by Kerber et al. (2023). A study on the evolution of cynodont skulls is published by Lautenschlager et al. (2023), who find no evindence for an increase in cranial strength and biomechanical performance during the cynodont–mammalian transition. A study on tooth replacement pattern and deciduous teeth in Haldanodon exspectatus is published by Martin & Schultz (2023), who interpret the fossil material of Peraiocynodon inexpectatus, P. major and Cyrtlatherium canei as likely to be docodont milk teeth. Averianov, Lopatin & Leshchinskiy (2023) reinterpret one of the supposed lower premolars of Sibirotherium rossicum as the first molariform, and consider S. rossicum to have five rather than six lower premolars. Mammals

Other animals

Other new animal taxa

Other animal research
 A study aiming to test the hypothesized feeding modes of Pectinifrons abyssalis is published by Darroch et al. (2023), who interpret their findings as supporting neither a suspension feeding or osmotrophic feeding habit, and indicating that rangeomorph fronds were organs adapted for oxygen uptake and gas exchange, rather than feeding. New information on the paleobiology of Culmofrons plumosa, based on data from specimens from the Trepassey Formation (Canada), is presented by Pasinetti & McIlroy (2023), who interpret rangeomorph impressions observed in Culmofrons as likely bundles of branches in the process of separating from the organism, potentially indicating that rangeomorphs had true modularity and the ability to separate modules as an asexual reproductive strategy. Purported fossil material of Dickinsonia reported from the Bhimbetka rock shelters in rocks of the Maihar Sandstone (India) is reinterpreted as an impression resulting from decay of a modern beehive by Meert et al. (2023). A study aiming to assess the validity of species distinctions in the genus Dickinsonia is published by Evans et al. (2023), who interpret their findings as indicative of the presence of two distinct species from South Australia, D. costata and D. tenuis. New information on the body plan of Dickinsonia, based on data from the fossil material from the southeastern White Sea area (Russia), is presented by Ivantsov & Zakrevskaya (2023), who interpret the anatomy of Dickinsonia as indicative of its affinity to the urbilaterian. Evidence indicative of the impact of oxygen expansion driven by sea-level oscillations on the speciation of early Cambrian reef-building archaeocyaths from the Siberian Craton is presented by Zhuravlev, Wood & Bowyer (2023). Yun et al. (2023) describe new fossil material of Hyalosinica archaica from the Cambrian Niutitang Formation (China), indicating that H. archaica developed a long stalk used to lift the main body above the sediment surface and reach more oxic water, and interpret H. archaica as a member of the stem group of Hexactinellida. Yun, Reitner & Zhang (2023) describe new, well-preserved fossil material of the chancelloriid Dimidia simplex from the Cambrian Yu'anshan Formation (China), and consider Dimidia to be a taxon distinct from Allonnia. A study on the body architecture of Xianguangia sinica is published by Zhao, Hou & Cong (2023), who interpret the putative "column" part of its body as formed by 18 tentacle-sheath complexes, and interpret X. sinica as a possible stem-ctenophore related to Dinomischus and Daihua. A specimen of the Ordovian hyolith Elegantilites custos with an operculum showing regeneration after non-lethal predatory attack is described by Fatka, Valent & Budil (2023). Parry et al. (2023) describe fossil material of Plumulites tafennaensis from the Ordovician (Katian) Upper Tiouririne Formation (Morocco), including aberrant shell plates interpreted as resulting from healed injuries, and consider the soft tissue that secreted the shell plate to be similar in morphology and size relative to the body to that seen in scaleworm elytra. Putative anostracan crustacean Gilsonicaris rhenanus is reinterpreted as a polychaete by Gueriau, Parry & Rabet (2023). New cycloneuralian microfossils, preserving a musculature system interpreted as indicative of a phylogenetic relationships with scalidophorans and possibly priapulans, are described from the Cambrian Kuanchuanpu Formation (China) by Zhang et al. (2023). Putative early leech from the Silurian Brandon Bridge Formation (Waukesha Biota; Wisconsin, United States) is considered to be a member of Cycloneuralia of uncertain affinities by Braddy, Gass & Tessler (2023). Wu, Pisani & Donoghue (2023) study the interrelationship between main groups of Panarthropoda, attempting to determine whether morphological datasets from the studies of extant and fossil panarthropod relationships published by Legg, Sutton & Edgecombe (2013), Yang et al. (2016) and Aria, Zhao & Zhu (2021) can discriminate statistically between competing Tactopoda, Lobopodia and Protarthopoda hypotheses, and question the accuracy of morphology-based phylogenies of Panarthropoda that include fossil species. Kihm et al. (2023) compare the morphology of tardigrades and Cambrian lobopodians, and argue that ancestral tardigrades likely had a Cambrian lobopodian–like morphology and shared most recent ancestry with the luolishaniids. New fossil material of Rotadiscus grandis is reported from the Cambrian Chengjiang biota from Yunnan (China) by Li et al. (2023), who recover Rotadiscus as a stem-ambulacrarian, and argue that such deuterostome traits as post-anal region, gill bars and a U-shaped gut evolved through convergence rather than shared ancestry. Claims of the presence of cellular cartilages, fibrillin and subchordal rod in yunnanozoan fossils made by Tian et al. (2022) are contested by He et al. (2023) and Zhang & Pratt (2023). Redescription of the holotype of Chamasaurus dolichognathus is published by Jenkins, Meyer & Bhullar (2023). A study on the anatomy and affinities of Tullimonstrum gregarium is published by Mikami et al. (2023), who interpret T. gregarium as more likely to be a non-vertebrate chordate or a protostome than a vertebrate. Other organisms

Other new organisms

Other organism research
 A study on the taphonomy of fossils of 2.1-billion-years-old soft-bodied organisms from the Franceville basin (Gabon) is published by Ngwal'ghoubou Ikouanga et al. (2023). Franz et al. (2023) describe the morphology and the internal structure of at least 1.5-billion-years-old organisms from the Volyn pegmatite field associated with the Korosten Pluton (Ukraine), reporting the presence of a large variation of different types of filaments in the studied organisms, and providing evidence of the presence of fungi-like organisms and continental deep biosphere by 1.5 billion years ago. Hoshino et al. (2023) study the distribution of hopanoid C-2 methyltransferase in the bacterial domain, and interpret their findings as indicating that Alphaproteobacteria evolved hopanoid C-2 methyltransferase around 750 million years ago, thus re-establishing 2-methylhopanes as cyanobacterial biomarkers before 750 Ma. Strullu-Derrien et al. (2023) describe new fossil material of nostocalean cyanobacteria from the Devonian Rhynie chert, interpret both new fossils and similar specimens that were already known (including fossils of Kidstoniella fritschii and Rhyniella vermiformis) as fossil material of a single species Langiella scourfieldii that belonged to the family Hapalosiphonaceae and thrived in soils, freshwater and hot springs like its extant relatives. Li et al. (2023) describe new fossil material of Horodyskia from the Tonian Shiwangzhuang and Jiuliqiao formations (China), and reconstruct Horodyskia as a colonial organism composed of a chain of organic-walled vesicles that likely represent multinucleated cells of early eukaryotes. Li et al. (2023) interpret discoidal fossils from the Tonian Jiuliqiao Formation (Anhui, China) as detached holdfasts of the worm-like annulated tubular fossils from the same formation. Evidence of widespread presence of pyritized spherical microorganisms (likely coccoid bacterial body fossils) on the surface of invertebrate fossils from the Lower Cretaceous Crato Formation (Brazil) is presented by Barling, Saleh & Ma (2023). Bryłka et al. (2023) reevaluate purported earliest fossils of diatoms from the Early and Middle Jurassic, and interpret them as unlikely to be fossil material of diatoms. Evidence of the impact of nutrient availability gradient on changes in the calcareous dinocyst assemblages is reported from the Turonian Dubivtsi Formation (Ukraine) by Ciurej, Dubicka & Poberezhskyy (2023). A study on the Cretaceous benthic foraminiferal assemblages from the Western Interior Seaway is published by Bryant, Meehan & Belanger (2023), who find no genera, guilds or morphotypes unique to cold seeps, and find assemblages from cold seeps to be overall more similar to offshore assemblages than nearshore ones, but also report that the composition of the studied assemblages did reflect the environmental differences present at seeps. A study on the fossil record of the planktonic foraminifera, interpreted as indicating that a modern-style latitudinal diversity gradient for these foraminifera arose only 15 million years ago, is published by Fenton et al. (2023). A study on the geographical distribution of the ecological and morphological groups of fossil planktonic foraminifera, interpreted as indicative of a global shift towards the Equator over the past 8 million years in response to the late Cenozoic temperature changes related to the polar ice sheet formation, is published by Woodhouse et al. (2023). Fonseca et al. (2023) describe possible fossil material of choanoflagellates from the Upper Cretaceous (Cenomanian–Turonian) Capas Blancas Formation (Spain), representing the first putative occurrence of choanoflagellates in the fossil record reported to date. An International team led by French-Morrocan Geologist Abderrazak El Albani unearths disc-shaped fossils of Eukaryotic origin in the Francevillian sedimentary deposits of Moulendé pushes back the origin of Planktonic origins 300 MA earlier than 570 MA. History of life in general
 Brocks et al. (2023) report the discovery of abundant protosteroids in sedimentary rocks of mid-Proterozoic age, and interpret this finding as evidence of the existence of a widespread and abundant biota of protosterol-producing bacteria and stem-group eukaryotes, living in aquatic environments from at least 1,640 to around 800 million years ago. Choudhuri et al. (2023) describe exceptionally-preserved bedding plane structures from the 1.6-billion-years-old Chorhat Sandstone (India), and argue that some of the studied structures were more likely to be created by movement through a microbiota-rich surficial sediment than by passive migration of any inorganic or organic masses under influence of an external force. Possible body and trace fossils, representing the oldest potential macrofossils from the Nama Group, are described from the lower Mara Member of the lower Dabis Formation (Tsaus Mountains, Namibia) by Wood et al. (2023), who interpret the studied fossils as remains of holdover soft-bodied taxa that appeared prior to the appearance of tubular and biomineralized animals. A study on the timing and environmental context of the earliest biotic assemblage from the Nama Group, based on data from the Dabis Formation (Tsaus Mountains, Namibia), is published by Bowyer et al. (2023), who interpret their findings as indicating that the evolution of skeletonization and the first appearance of Cloudina happened in open marine carbonate settings and might have been driven by major sea level lowstands. Kolesnikov et al. (2023) report the discovery of the fossil material of Ediacara-type soft-bodied organisms, including palaeopascichnids, arboreomorphs, chuariomorphids, microbial colonies, from the Dzhezhim Formation of the Timan Range (Komi Republic, Russia). Revision of the Ediacaran fossils and pseudofossils from the Ura Formation (Patom Basin; Russia) is published by Petrov & Vorob'eva (2023). Mussini & Dunn (2023) interpret the gradual but escalatory upping of ecological pressure resulting from evolutionary innovations such as bioturbation, predation and reef building as likely to be the most significant cause of the replacement of the Ediacaran biota by Phanerozoic biotas dominated by crown eumetazoans, and argue that changes to the originally homogenous distribution of resources in the benthos initiated by the Ediacaran biota itself might have driven the origins of bilaterians, their evolutionary innovations and ultimately their takeover. Servais et al. (2023) review estimates of taxonomic richness of marine organisms during the early Paleozoic based on different published datasets, and question the existence of a distinct Cambrian explosion and global Ordovician biodiversification event instead of a single, long-term radiation of life during the early Paleozoic. Evidence indicating that continental configuration and climate state specific to the early Paleozoic resulted in higher susceptibility of marine animals to extinction than during the rest of the Phanerozoic is presented by Pohl et al. (2023). A study on the extinction selectivity of benthic brachiopods belonging to the groups Rhynchonellata and Strophomenata, gastropods, bivalves and trilobites throughout the Phanerozoic is published by Monarrez, Heim & Payne (2023), who report evidence of stronger extinction selectivity with respect to geographical range than body size, particularly during background intervals, but also evidence indicating that Phanerozoic mass extinctions may have been overall less selective than extinctions during background intervals, as well as indicative of more variable strength and direction of extinction selectivity by clade during Phanerozoic mass extinctions relative to background intervals. Høyberget et al. (2023) report the discovery of a new, diverse early Cambrian biota (the Skyberg Biota) from the Skyberg Member of the Ringstranda Formation (Norway). Li et al. (2023) compare the lamello-fibrillar nacre and similar fibrous microstructures in Early Cambrian molluscs and hyoliths from the Zavkhan Basin (Mongolia) and in extant coleoid cuttlebones and serpulid tubes, report differences in shell microstructures of the studied lophotrochozoan groups, and interpret their findings as indicative of prevalence of calcitic shells in the Terreneuvian. A study aiming to identify the biases affecting the knowledge of the biodiversity during the Cambrian and Ordovician is published by Du et al. (2023), who interpret the significant decline in known biodiversity during Furongian interval as influenced by temporal, geographic, taxonomic and lithological biases, hindering the understanding of the real biodiversity changes in this interval. Eliahou Ontiveros et al. (2023) study possible causes of the Great Ordovician Biodiversification Event, and interpret global cooling as the most likely primary driver. A diverse Ordovician fauna (the Castle Bank fauna), comparable with the Burgess Shale and Chengjiang biotas in paleoenvironment and preservational style, is described from Wales (United Kingdom) by Botting et al. (2023). A study on the structure of the Givetian shallow-water reef ecosystem from the Madène el Mrakib site (Morocco) is published by Majchrzyk et al. (2023), who report that the studied community from most known Devonian reefs, as it was dominated by large branching tabulate corals while stromatoporoids were of minor importance, and note similarities between the studied community and extant shallow-water reefs. A study on the fossil record of tetrapods living from the Bashkirian to the Kungurian is published by Dunne et al. (2023), who argue that apparent changes in diversity of the studied tetrapods can be explained by variation in sampling intensity through time. Francischini et al. (2023) describe straight, curved and quasi-helical burrows from the Permo-Triassic Buena Vista Formation (Brazil), similar to burrows reported from the Karoo Basin of South Africa, and interpret the studied burrows as likely produced by synapsids and/or procolophonians living in a desert environment, representing the oldest unambiguous record of tetrapod dwelling structures in such an environment. A study on the impact of the Permian–Triassic extinction event on the marine ecosystems is published by Huang et al. (2023), who find that the first extinction phase resulted in the loss of more than half of taxonomic diversity but only a slight decrease of community stability, which subsequently decreased significantly in the second extinction phase. Evidence indicating that reef recovery in the aftermath of the Permian–Triassic extinction was gradual and delayed compared to nonreef ecosystems is presented by Kelley et al. (2023). Dai et al. (2023) report the discovery of an exceptionally preserved Early Triassic (approximately 250.8 million years ago) fossil assemblage (the Guiyang biota) from the Daye Formation near Guiyang (China), providing evidence of the existence of a complex marine ecosystem shortly after the Permian–Triassic extinction event. Czepiński et al. (2023) report the discovery of a new, diverse vertebrate assemblage from the Ladinian Miedary site (Poland), including abundant fossil material of Tanystropheus, making the studied site the richest source of three-dimensionally preserved Tanystropheus material in the world reported to date. New information on the composition of the Late Triassic paleocommunity from the Polzberg Lagerstätte (Austria), based on data from thousands of new fossils, is published by Lukeneder & Lukeneder (2023). El Atfy, Abeed & Uhl (2023) describe a diverse assemblage of non-pollen palynomorphs from the Lower Cretaceous (Berriasian-Valanginian) Yamama Formation (Iraq), and interpret the studied assemblage as deposited in anoxic, neritic conditions relatively near to the land. Del Mouro et al. (2023) provide evidence of the preservation of organic walled microfossils (including pollen grains, spores and acritarchs) from wet peperites from the Lower Cretaceous Paraná-Etendeka intertrappean deposits of the Paraná Basin (Brazil), and interpret the studied microfossils as indicative of changes from desertic to more humid conditions in south-central Gondwana during the Valanginian. Cortés & Larsson (2023) reconstruct the ecological network of the marine Mesozoic fauna from the Lower Cretaceous Paja Formation (Colombia), who report that the largest marine reptile predators from the studied fauna occupied higher trophic levels than any extant marine apex predator. A study on the fossil record of Late Cretaceous invertebrates from the Western Interior Seaway and the adjacent Gulf Coastal Plain is published by Purcell, Scuderi & Myers (2023), who interpret their findings as indicating that the Western Interior Seaway did not contain biotic subprovinces in the Late Cretaceous, but faunal associations were affected by sea-level changes. Bobe et al. (2023) describe fossil material of marine and terrestrial animals (including a new hyrax taxon) and woods from new sites from the Miocene Mazamba Formation (Mozambique), and interpret the studied sites as formed in coastal settings. Hayward et al. (2023) report the discovery of a diverse Pliocene (Waipipian) fauna from sediment excavated from two shafts at Māngere Wastewater Treatment Plant (New Zealand), dominated by molluscs and including new species records for New Zealand, as well as extending known time ranges of taxa already known from New Zealand. Harrison et al. (2023) provide the systematic account of the Pliocene fauna from the Lower Laetolil Beds (Laetoli, Tanzania). A study on the timing of Pleistocene megafaunal extinction in the high plains of Peru is published by Rozas-Davila, Rodbell & Bush (2023), who find that the collapse of megafaunal populations in high grasslands coincided with upticks in fire activity, which were likely associated with human activity. Martinez et al. (2023) find no evidence of a significant relation between the relative surface area of the maxilloturbinal and physiological traits such as metabolism and body temperature in extant mammals, and interpret their findings as challenging the hypothesis positing that respiratory turbinals reflect the thermal and metabolic physiology in extant and extinct tetrapods (especially in mammals). Other research
 A study on changes to the regional and global geochemical environment in the aftermath of the Sturtian glaciation is published by Bowyer et al. (2023), who find that the shift to dominant green algal primary production and the first appearance of putative sponges and problematic macrofossils might be related to global stabilization of geochemical environments following the deglaciation, to the expansion of less reducing (and likely more oligotrophic) marine environments, and to the shift from postglacial super-greenhouse conditions to a cooler climate. Evidence from the Cryogenian Nantuo Formation (China), interpreted as indicating that habitable open ocean conditions providing refugia for eukaryotic organisms during the Marinoan glaciation extended into mid-latitude coastal oceans, is presented by Song et al. (2023). Evidence of the impact of tectonic and ecological factors on redox changes in upper ocean, deep shelf and restricted basin settings throughout the Phanerozoic, which in turn were correlated with background extinction rates of marine animals, is presented by Wang et al. (2023). A study on the stratigraphy of the Siberian Platform (Russia), and on its implications for the knowledge of the age of the fossils and timing of first appearances of late Ediacaran and early Cambrian organisms from the Siberian Platform (including anabaritids and cloudinids), is published by Bowyer et al. (2023). Nelson et al. (2023) present high-precision age constraints for the lower Wood Canyon Formation (Nevada, United States), and interpret their findings as indicating that the base of the Cambrian Period was younger than 533 million years ago, making the early Cambrian animal radiation faster than previously recognized. Nolan et al. (2023) interpret Brooksella alternata as a likely pseudofossil, and the bulk of its characteristics as consistent with concretions. Wellman et al. (2023) present data supporting a Silurian (late Wenlock) age of the "Lower Old Red Sandstone" deposits of the Midland Valley (Scotland, United Kingdom) preserving the fossil material of Pneumodesmus newmani, supporting the interpretation of this myriapod as the oldest known air-breathing land animal. A study on the preservation of chemical information in the fossils from the Devonian Rhynie chert (United Kingdom) is published by Loron et al. (2023), who report that differences between prokaryotes and eukaryotes and between eukaryotic tissue types from the Rhynie chert assemblage can be identified based on the fossilization products of lipids, sugar and protein. A study on the geochemistry of the Bakken Formation, interpreted as indicative of stepwise transgressions of toxic euxinic waters into the shallow oceans that drove a series of Late Devonian extinction events, is published by Sahoo et al. (2023). Evidence from mercury concentrations and isotopes from terrestrial sections from the Sydney Basin (Australia) and Karoo Basin (South Africa), interpreted as indicative of global volcanic effects of the Siberian Traps during the Permian-Triassic transition, is presented by Shen et al. (2023). Evidence from concentrations of UV-B–absorbing compounds in the exine of fossil pollen from the Qubu section in southern Tibet (China), interpreted as consistent with increased UV-B radiation during the Permian–Triassic extinction event, is presented by Liu et al. (2023); their conclusions are subsequently contested by Seddon & Zimmermann (2023). Lovelace et al. (2023) present data supporting a Carnian age for the majority of the Popo Agie Formation. Sedimentologic evidence of glaciers developing in continental Iberia during the Hauterivian is reported from the Enciso Group in the eastern Cameros Basin (Spain) by Rodríguez-López et al. (2023). A study on the Cenomanian–Turonian benthic foraminiferal assemblages from the Western Interior Seaway is published by Bryant & Belanger (2023), who report that the interval of increased density and diversity of benthic foraminifera known as the Benthonic Zone is not a reliable biostratigraphic marker for the onset of the Oceanic Anoxic Event 2 in the Western Interior Seaway, and that different samples of the Benthonic Zone don't reflect basin-wide changes in oxygenation. Evidence from two sites offshore of southwest Australia, interpreted as indicative of ocean acidification at the onset of Oceanic Anoxic Event 2 which was linked to the onset of volcanic activity, and which persisted for approximately 600,000 years due to biogeochemical feedbacks, is presented by Jones et al. (2023). Evidence from concentrations of sulfur and fluorine in Deccan Traps lavas, interpreted as indicative of recurring eruptive pulses of Deccan Traps volcanism before the Cretaceous–Paleogene extinction event which might have caused short-lived global drops in temperature, is presented by Callegaro et al. (2023). A study on the history of the Eocene waterbody within the Giraffe Pipe crater (Northwest Territories, Canada), inferred from changes in the fossil record of microorganisms, is published by Siver & Lott (2023), who interpret their findings as indicative of the presence of a series of successive shallow environments, each correlated with changes in lakewater chemistry. Evidence from tooth enamel of specimens of Hippopotamus antiquus from Early Pleistocene sites in Southern and Central Europe (primarily from Upper Valdarno and Vallparadís Section in Italy and Spain, respectively), interpreted as indicative of a progressive increase of environmental seasonality around the Mediterranean Basin during the Early Pleistocene, is presented by Fidalgo et al. (2023). Abbas et al. (2023) report the presence of Late Quaternary wetland sediments at the Wadi Hasa, Gregra and Wadi Gharandal areas in the Jordan desert, and interpret their findings as indicating that during the Marine Isotope Stage 5 the Levant was a well-watered route for human dispersal out of Africa. Essel et al. (2023) report the development of a new method for the gradual release of DNA trapped in ancient bone and tooth artefacts, and use this method to recover ancient human and deer mitochondrial genomes from the Upper Paleolithic deer tooth pendant from Denisova Cave (Russia). Reeves & Sansom (2023) present a new method which can be used to determine the impact of multiple factors (decay, ontogeny and phylogeny) on morphological variation between fossils, and apply this method to fossils of Tethymyxine, Mayomyzon, Priscomyzon, "euphaneropoids" and Palaeospondylus. Wang, Shu & Wang (2023) present a new method for element mapping of the fossils' 3D surface using nondestructive X-ray fluorescence, providing information on degraded material from the soft body parts in the sediments surrounding the studied fossil specimens, and apply this method to a specimen of Keichousaurus hui. Slater et al. (2023) study the impact of thermal maturation on eumelanin and phaeomelanin, develop a predictive model for authentic signals for eumelanin and phaeomelanin in fossil tissues, and use this model to provide molecular evidence of preservation of eumelanin in fossil feathers of Confuciusornis, as well as molecular evidence of preservation of phaeomelanin in the fossil material of the Miocene frog Pelophylax pueyoi. Brooke et al. (2023) demonstrate the utility of agent-based modelling for study of the ecologies of past ecosystems, using such a model to determine the drivers of distribution of large ungulates from the Palaeo-Agulhas Plain during the peak of the Last Glacial Maximum. Paleoclimate
 A study on the evolution of the monsoon system over the past 250 million years, providing evidence of the impact of continental area, latitudinal location and fragmentation, is published by Hu et al. (2023). Evidence indicating that injection of the silicate dust from the Chicxulub impact into the atmosphere contributed to the global cooling and disruption of photosynthesis that followed is presented by Senel et al. (2023). Evidence from seawater osmium isotope data from Pacific Ocean sediments, interpreted as indicating that enhanced magmatism could have played a dominant role in causing the Miocene Climatic Optimum, is presented by Goto et al. (2023). Wen et al. (2023) present a new land surface temperature record from the Chinese Loess Plateau in East Asia, interpreting it as indicative of late Miocene cooling and aridification that occurred synchronously with ocean cooling, highlighting a global climate forcing mechanism. Evidence of periodic deposition of sapropelic mud in Eastern Mediterranean during the Plio-Pleistocene and records of precipitation and vegetation from leaf wax biomarkers from the studied sapropel layers, interpreted as indicative of the impact of orbital cycles on monsoon variability in northeast Africa and on greening of the Sahara which created routes of dispersal out of Africa for hominins, is presented by Lupien et al. (2023). Margari et al. (2023) provide evidence of pronounced climate variability in Europe during a glacial period ~1.154 to ~1.123 million years ago, culminating in extreme glacial cooling, and argue that these conditions led to the depopulation of Europe. References