2020 in paleontology

Plants

Sponges

Cnidarians

Arthropods

Bryozoans

Brachiopods

New taxa

Molluscs

Echinoderms

New taxa

Research

• A study on morphological diversification of echinoderms and evolutionary mechanisms underlying the establishment of echinoderm body plans during the early Paleozoic is published by Deline et al..
• A study on the locomotion of cornute stylophorans, based on data from a specimen of Phyllocystis crassimarginata from the Ordovician Saint-Chinian Formation, is published by Clark et al..
• A study on the morphology and phylogenetic relationships of Hexedriocystis is published by Zamora & Sumrall, who consider this taxon to be a blastozoan.
• A study on the speciation and dispersal of the diploporan blastozoans through the Ordovician period is published by Lam, Sheffield & Matzke.
• A study on the evolutionary history of eublastoid blastozoans is published by Bauer.

  Conodonts

New taxa

Research

• Evidence of variations in crystallography and microstructure due to both ontogeny and element type within the conodont feeding apparatus of Dapsilodus obliquicostatus is presented by Shohel et al., who evaluate the implications of their findings for the knowledge of the integrity of conodont apatite as a recorder of seawater chemistry.

  Fishes

Amphibians

New taxa

Research

• A study evaluating the effects of ontogenetic disparity of known trematopid specimens on reconstructions of the phylogenetic relationships of trematopids is published by Gee.
• Redescription of Actiobates peabodyi, including an updated description of the skull and the first description of the postcranial skeleton, is published by Gee & Reisz.
• New amphibamiform specimen with exceptionally preserved lissamphibian-like integumentary structures, including the first evidence of toepad structures in a temnospondyl body fossil, is described from the Mazon Creek fossil beds by Mann & Gee.
• A study on growth patterns in Doleserpeton annectens, as indicated by bone histology, is published by Gee, Haridy & Reisz.
• A study on a specimen of Benthosuchus korobkovi from the Olenekian of Russia affected by a neoplastic bone lesion in its jaw, representing the earliest case of such lesion in a tetrapod reported so far, is published by Novikov et al., who propose a non-odontogenic osteoma as the most likely diagnosis.
• Redescription and a study on the phylogenetic relationships of Aphaneramma kokeni is published by Maisch, who considers A. kokeni to be a valid taxon.
• Evidence of the presence of five metacarpals in a specimen of Metoposaurus krasiejowensis from the Upper Triassic of Poland is presented by Konietzko‐Meier et al., who interpret this finding as evidence of pentadactyly of the manus of M. krasiejowensis, showing that the presence of a five-digit manus among Temnospondyli was possible.
• New specimen of Triassurus sixtelae is described from the Triassic of Kyrgyzstan by Schoch, Werneburg & Voigt, who identify this species as the oldest known stem-group salamander.
• A study on the diversity of skull shape in extant and fossil ribbed and crocodile newts, the relationship between their skull shape and ecological and reproductive traits, and its implications for the knowledge of the ecology of Chelotriton, is published by Pogoda et al..
• Right ilium and a skull bone of a frog belonging to the genus Calyptocephalella are reported from the Eocene La Meseta Formation by Mörs, Reguero & Vasilyan, representing the first record of a lissamphibian in Antarctica reported so far.
• Partial humerus of a member of the genus Eleutherodactylus is described from the Oligocene San Sebastian Formation by Blackburn et al., representing the earliest fossil frog from any Caribbean island reported so far.
• A study on the long bone histology, growth rate and the timing of the attainment of sexual maturity in seymouriamorphs is published by Jordi Estefa et al..
• A study on the anatomy of the braincase and otic capsule of Seymouria is published by Bazzana et al..
• Description of new postcranial material of Seymouria from the Richards Spur locality, and a study on bone histology, life histories and evolution of terrestriality of seymouriamorphs, is published by Bazzana et al..
• A study on the anatomy of the skull of Euryodus dalyae, providing new information on the anatomy of the braincase and mandible, is published by Gee, Bevitt & Reisz.
• Description of the anatomy of the braincase and stapes of Diadectes absitus is published by Klembara et al..

  Reptiles

Synapsids

Non-mammalian synapsids

New taxa

Research

• A study on the evolution of the well-defined morphological regions of the vertebral column and of vertebral functional diversity in synapsids is published by Jones et al..
• A study aiming to determine the resting metabolic rates and the thermometabolic regimes in eight non-mammalian synapsids is published by Faure-Brac & Cubo.
• A study on the shoulder musculature in extant Argentine black and white tegu and Virginia opossum, evaluating its implications for reconstructions of the shoulder musculature in non-mammalian synapsids, is published by Fahn-Lai, Biewener & Pierce.
• Mann et al. reinterpret Carboniferous taxon Asaphestera platyris Steen from the Joggins locality as the earliest unambiguous synapsid in the fossil record reported so far.
• A study on the long bone histology of varanopids from the lower Permian Richards Spur locality, evaluating its implications for the knowledge of the paleobiology of early synapsids, is published by Huttenlocker & Shelton.
• Mann & Reisz report a new hyper-elongated neural spine of Echinerpeton intermedium from the Pennsylvanian-aged Sydney Mines Formation, indicating a wider distribution of hyper-elongation of vertebral neural spines in early synapsids than previously known.
• A study on the histology of vertebral centra of Edaphosaurus and Dimetrodon is published by Agliano, Sander & Wintrich.
• A study on the anatomy of the holotype skull of Tetraceratops insignis and on the phylogenetic relationships of this taxon is published by Spindler.
• A study comparing the oxygen and carbon stable isotope compositions of tooth and bone apatite of Endothiodon and Tropidostoma, and aiming to determine the ecology and diet of Endothiodon, is published by Rey et al..
• Redescription of the skull of Lycosuchus vanderrieti, providing new information on the endocranial anatomy of this taxon, is published by Pusch et al..

  Mammals

Other animals

New taxa

Research

• Evidence of preservation of internal anatomical structures in cloudinomorph fossils from the Ediacaran Wood Canyon Formation is reported by Schiffbauer et al., who interpret these structures as probable digestive tracts, and evaluate their implications for the knowledge of the phylogenetic relationships of cloudinomorphs.
• New specimens of Mafangscolex, providing the first detailed information on the anatomy of a proboscis in palaeoscolecids, are described from the Cambrian Xiaoshiba Lagerstätte by Yang et al..
• A study on the type material of a putative Ordovician annelid Haileyia adhaerens is published by Muir & Botting who find no evidence indicating that H. adhaerens is an annelid, or even a recognizable fossil.
• Two types of microscopic reticulate cuticular patterns are described in Cambrian stem-group scalidophorans from the Kuanchuanpu Formation by Wang et al., who argue that these cuticular networks replicate the cell boundaries of the epidermis.
• A study on the anatomy and phylogenetic relationships of Facivermis yunnanicus, based on data from the holotype and new specimens, is published by Howard et al., who consider this species to be a luolishaniid lobopodian.
• An isolated frontal appendage of a miniature hurdiid radiodont is described from the Ordovician Dol-cyn-Afon Formation by Pates et al., representing the first radiodont reported from the UK, the first record of this group from the palaeocontinent Avalonia, and the first from an environment dominated by sponges rather than euarthropods.

  Foraminifera

Other organisms

New taxa

Research

• Putative ciliate fossils from the Cryogenian Taishir Formation are reinterpreted as more likely to be algal reproductive structures by Cohen, Vizcaíno & Anderson, who also report the first occurrence of these fossils in the earliest Ediacaran Ol Formation.
• The discovery of fungal fossils in a 810 to 715 million year old dolomitic shale from the Mbuji-Mayi Supergroup is reported by Bonneville et al., representing the oldest, molecularly identified remains of Fungi reported so far.
• A study on the developmental biology and phylogenetic relationships of Helicoforamina wenganica is published by Yin et al..

  Trace fossils

• A study on patterns of ecosystem engineering behaviors across the Permian-Triassic boundary, as indicated by data from trace fossils, and on their possible impact on ecosystem recovery in the benthic environment in the aftermath of the Permian–Triassic extinction event is published by Cribb & Bottjer.
• New fossil tracks, probably produced by a pterygote insect, are described from the Upper Jurassic-Lower Cretaceous Botucatu Formation by Peixoto et al., who name a new ichnotaxon Paleohelcura araraquarensis, and evaluate the implications of this finding for the knowledge of ecological relationships within the Botucatu paleodesert.
• New tetrapod trackways are described from the Tapinocephalus Assemblage Zone of the South African Karoo Basin by Cisneros et al., who interpret these tracks as produced by small amphibians, and consider them to be evidence that the diversity of Guadalupian amphibians of the Karoo Basin was greater than indicated by body fossils alone.
• Mujal & Schoch describe amphibian tracks from the Middle Triassic Erfurt Formation by Kim et al., who name a new ichnotaxon Batrachopus grandis.
• Three sauropod trackways, probably produced by members of Titanosauriformes, are described from the Middle Jurassic of the Castelbouc cave by Moreau et al., who name a new ichnotaxon Occitanopodus gandi.
• New dinosaur tracks, including tracks representing the ichnogenus Deltapodus, are described from the Middle Jurassic of the Isle of Skye by dePolo et al., expanding known diversity of dinosaur tracks from this locality.
• Flamingo-like and anatid-like fossil bird footprints will be described from the Vinchina Formation by Farina et al., who name new ichnotaxa Phoenicopterichnum lucioi and P. vinchinaensis.
• Mazin & Pouech describe non-pterodactyloid pterosaur tracks from the ichnological site known as "the Pterosaur Beach of Crayssac", evaluate the implications of these tracks for the knowledge of the terrestrial capabilities of non-pterodactyloid pterosaurs, and name a new ichnogenus Rhamphichnus.
• Dinosaur and synapsid tracks are described from the Pliensbachian-Toarcian of the northern main Karoo Basin by Bordy et al., who interpret these tracks as evidence that dinosaurs and synapsids were among the last inhabitants of the main Karoo Basin some 183 million years ago, and name a new ichnotaxon Afrodelatorrichnus ellenbergeri.
• New complex burrow system produced by geomyid rodents is described from the Oligocene Chilapa Formation by Guerrero-Arenas, Jiménez-Hidalgo & Genise, who name a new ichnotaxon Yaviichnus iniyooensis, and interpret the complexity of these burrows as probable evidence of some degree of gregariousness of their producers.

  History of life in general

• Liu & Dunn, describe filamentous organic structures preserved among frond-dominated fossil assemblages from the Ediacaran of Newfoundland, including filaments that appear to directly connect individual specimens of one rangeomorph taxon, and interpret this finding as possible evidence that Ediacaran frondose taxa were clonal.
• A study on the age of the Ediacaran biota from the Conception and St. John’s Groups at Mistaken Point Ecological Reserve is published by Matthews et al..
• Approximately 563-million-year-old Ediacaran biota is reported from the Itajaí Basin by Becker-Kerber et al., representing the first record of Ediacaran macrofossils from Gondwana in deposits of similar age to the Avalon biota.
• A study on biomarkers from Ediacaran sediments in the White Sea area is published by Bobrovskiy et al., who interpret their findings as indicating that eukaryotic algae were abundant among the food sources available for the Ediacaran biota.
• A study aiming to quantify changes of regional-scale diversity in marine fossils across time and space throughout the Phanerozoic is published by Close et al..
• A study on the timing of known diversification and extinction events from Cambrian to Triassic, based on data from 11,000 marine fossil species, is published by Fan et al..
• The discovery of a new, exceptionally-preserved Cambrian biota, with fossils belonging to multiple phyla, is reported from the Guzhangian Longha Formation by Peng et al..
• A study on changes in body size in skeletal animals from the Siberian Platform through the early Cambrian is published by Zhuravlev & Wood.
• A study on the relationship between body size and extinction risk in the marine fossil record across the past 485 million years is published by Payne & Heim.
• A study on the diversification rates of Ordovician animals living on hard substrates, aiming to determine when they experienced their greatest origination rates, is published by Franeck & Liow.
• New information on the biotic composition of the Silurian Waukesha Lagerstätte is presented by Wendruff et al., who report a biodiversity far richer than previously reported, and explore the taphonomic history of the fossils of this biota.
• A study on the diversity dynamics of the marine brachiopods, bivalves and gastropods throughout the Late Palaeozoic Ice Age is published by Seuss, Roden & Kocsis.
• A study comparing the chemistry of fossil soft tissues of invertebrates and vertebrates from the Carboniferous Mazon Creek fossil beds is published by McCoy et al., who report Tullimonstrum gregarium as grouping with vertebrates in their analysis.
• A study on the ages of known early–middle Permian tetrapod-bearing geological formations, as indicated by Bayesian tip dating methods, is published by Brocklehurst, who interprets his findings as supporting the occurrence of the Olson's Extinction.
• A study on global infaunal response to the Permian–Triassic extinction event, as indicated by data from trace fossils, is published by Luo et al..
• A study on changes of marine latitudinal diversity gradient caused by the Permian–Triassic mass extinction is published by Song et al..
• Description of new fossil material of Late Triassic tetrapods from the Hoyada del Cerro Las Lajas site, and a study on the age of tetrapod fossils from this site and their implications for the knowledge of the Late Triassic tetrapod evolution, is published by Desojo et al..
• A study on the dynamics of the Adamanian/Revueltian faunal turnover, based on fossil data from the Petrified Forest National Park, is published by Hayes et al..
• Wignall & Atkinson argue that the Triassic–Jurassic extinction event can be resolved into two distinct, short-lived extinction pulses separated by a several hundred-thousand-year interlude phase.
• A study on changes in shell size of marine bivalves and brachiopods from the Iberian Basin across the Early Toarcian Oceanic Anoxic Event, aiming to determine the role of temperature for changes in body size of bivalves and brachiopods, is published by Piazza, Ullmann & Aberhan.
• Foster, Pagnac & Hunt-Foster describe the Late Jurassic biota from the Little Houston Quarry in the Black Hills of Wyoming, including the vertebrate fauna which is the second-most diverse in the entire Morrison Formation and the most diverse north of Como Bluff.
• A study on the age of the Huajiying Formation and its implications for the knowledge of the timing of appearance and duration of the Jehol Biota is published by Yang et al..
• A study on extinction patterns of marine vertebrates during the last 20 million years of the Late Cretaceous, as indicated by fossils from northern Gulf of Mexico, is published by Ikejiri, Lu & Zhang, who report evidence of two separate extinction events: one in the Campanian, and one at the end of the Maastrichtian.
• Rodríguez-Tovar et al. present evidence from trace fossils from the Chicxulub crater indicating that full recovery of the macrobenthic biota from this area was rapid, with the establishment of a well-developed tiered community within ~700 thousand years.
• A study on the impact of the early Cenozoic hyperthermal events on shallow marine benthic communities, based on data from fossils from the Gulf Coastal Plain, is published by Foster et al..
• A study on the geology and fauna of the new Mille-Logya site dated to between 2.914 and 2.443 Ma is published by Zeresenay Alemseged et al., who evaluate the implications of this site for the knowledge of how hominins and other fauna responded to environmental changes during this period.
• A new, diverse megafauna assemblage that suffered extinction sometime after 40,100 years ago is reported from the South Walker Creek fossil deposits by Hocknull et al., who evaluate the implications of this assemblage for prevailing megafauna extinction hypotheses for Sahul.
• A study on ancient DNA of vertebrates and plants recovered from fossils and sediment from Hall’s Cave, evaluating its implications for the knowledge of the climatic fluctuations from the Pleistocene to the Holocene on the local ecosystem, is published by Seersholm et al..
• A study on the phylogenetic relationships of early amniotes, recovering Parareptilia and Varanopidae as nested within Diapsida, will be published by Ford & Benson, who name a new clade Neoreptilia.
• Regional-scale diversity patterns for terrestrial tetrapods throughout their entire Phanerozoic evolutionary history are presented by Close et al., who attempt to determine how informative the fossil record is about true global paleodiversity.
• A study on the impact of the appearance and evolution of herbivorous tetrapods on the evolution of land plants from the Carboniferous to the Early Triassic is published by Brocklehurst, Kammerer & Benson.
• A study the terrestrial and marine fossil record of Late Permian to Late Triassic tetrapods, comparing species-level tetrapod biodiversity across latitudinal bins, is published by Allen et al..
• In a study published by Chiarenza et al. the two main hypotheses for the mass extinction were evaluated using Earth System and Ecologial modelling, confirming that the asteroid impact was the main driver of this extinction while the volcanism might have boosted the recovery instead.

  Other research

• Evidence indicating that the Great Oxidation Event predated Paleoproterozoic glaciation in Russia and snowball Earth deposits in South Africa is presented by Warke et al., who argue that their findings preclude hypotheses of Earth’s oxygenation in which global glaciation preceded or caused the evolution of oxygenic photosynthesis.
• A study on the timing of the onset and termination of the Shuram carbon isotope excursion is published by Rooney et al., who argue that this excursion was divorced from the rise of the earliest preserved animal ecosystems.
• A study on the causes of the Late Ordovician mass extinction, based on data from the Ordovician-Silurian boundary stratotype, is published by Bond & Grasby, who interpret their findings as evidence that this extinction event was caused by volcanism, warming and anoxia.
• Evidence of wildfires at the Frasnian−Famennian boundary is reported from Upper Devonian sections from western New York by Liu et al., who also provide an estimate of atmospheric O₂ levels at this interval, and evaluate their implications for the knowledge of causes of the Late Devonian extinction.
• Evidence of anomalously high mercury concentration in marine deposits encompassing the Hangenberg event from Carnic Alps is presented by Rakociński et al., who argue that methylmercury poisoning in otherwise anoxic seas, caused by extensive volcanic activity, could be a direct kill mechanism of the end-Devonian Hangenberg extinction.
• A study on fossil plant spores with malformed sculpture and pigmented walls, recovered from terrestrial Devonian-Carboniferous boundary sections from East Greenland, is published by Marshall et al., who interpret their findings as evidence that the terrestrial mass extinction at the Devonian-Carboniferous boundary coincided with elevated UV-B radiation indicatice of ozone layer reduction.
• A study on the age of a pristine ash-fall deposit in the Karoo Lystrosaurus Assemblage Zone is published by Gastaldo et al., who report that turnover from the Daptocephalus Assemblage Zone to Lystrosaurus AZ in this basin occurred over 300 ka before the end-Permian marine event, and interpret their findings as refuting the concurrentness of turnovers in terrestrial and marine ecosystems at the end of the Permian.
• A study evaluating the contribution of loss of ecosystems on land and consequent massive terrestrial biomass oxidation to atmosphere–ocean biogeochemistry at the Permian–Triassic boundary is published by Dal Corso et al..
• A study on variations of ~10-Myr scale monsoon dynamics during the early Mesozoic, and on their impact on climate and ecosystem dynamics, is published by Ikeda, Ozaki & Legrand.
• New geochronologic and paleoclimatic data from Carnian-aged strata in the Ischigualasto-Villa Unión Basin is presented by Mancuso et al., who interpret their findings as indicating that the Carnian Pluvial Event interval in western Gondwana was warmer and more humid than periods before or after this interval, confirming that the CPE was a global event.
• A study on ocean temperatures during the Triassic–Jurassic extinction event is published by Petryshyn et al., who report no evidence for short-term cooling or initial warming across the 1-80,000 years of the extinction event.
• A review of the geology, paleoecology and taxonomic status of the fauna from the Cretaceous Kem Kem Beds of Morocco is published by Ibrahim et al..
• Klages et al. report evidence from the West Antarctic shelf indicating the occurrence of a temperate lowland rainforest environment at a palaeolatitude of about 82° S during the Late Cretaceous.
• A study on the timing of a volcanic outgassing at the end of the Cretaceous, and on its implications for the knowledge of causes of the Cretaceous-Paleogene mass extinction, is published by Hull et al..
• A study on paleosols from the eastern edge of the Deccan Volcanic Province, evaluating their implications for reconstructions of climate and terrestrial environments of India before and after the Cretaceous–Paleogene extinction event and for the knowledge of causes of this extinction event, is published by Dzombak et al..
• A study on the origin, recovery, and development of microbial life in the Chicxulub crater after the impact at the end of the Cretaceous, and on the environmental conditions in the crater up to ∼4 million years after the Cretaceous–Paleogene extinction event, is published by Schaefer et al..
• A study on freshwater fauna and flora found in a sediment sample from the Yuka mammoth carcass, evaluating its implications for reconstructions of the waterbody type where the mammoth was preserved and for the knowledge of the nature of the waterbodies that existed in Beringia during the MIS3 climatic optimum, is published by Neretina et al..
• Partial dentary of a juvenile saurornitholestine dromaeosaurid is described from the Upper Cretaceous Prince Creek Formation by Chiarenza et al., representing the first confirmed non-dental fossil specimen of a member of Dromaeosauridae in the Arctic.
• Van Neer et al. report faunal remains from the Takarkori rock shelter in the Acacus Mountains region, and evaluate their implications for the knowledge of the climate and hydrography of the Sahara throughout the Holocene.
• New Mesozoic and Paleogene amber occurrences, preserving diverse inclusions of arthropods, plants and fungi, are reported from Australia and New Zealand by Stilwell et al..