# 2020 in arthropod paleontology

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2020 in arthropod paleontology is a list of new arthropod fossil taxa, including arachnids, crustaceans, insects, trilobites, and other arthropods that were announced or described, as well as other significant arthropod paleontological discoveries and events which occurred in 2020.

## Arachnids
### Newly named taxa

| Name | Novelty | Status | Authors | Age | Type locality | Country | Notes |
| Aliendiguetia | Gen. et sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider of uncertain phylogenetic placement, possibly related to the Ochyroceratoidea. The type species is A. praecursor. |
| Bicornoculus granulans | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Tetrablemmidae. |
| Biungulus | Gen. et sp. nov | In press | Bartel et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A member of Opiliones belonging to the family Epedanidae. Genus includes new species B. xiai. |
| Burmacharon | Gen. et sp. nov | In press | Hu et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A whip spider. Genus includes new species B. dunlopi. |
| Burmesarchaea bilongapophyses | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Archaeidae. |
| Burmesia | Gen. et sp. nov | Junior homonym | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to family Nemesiidae. The type species is B. sordida. The generic name is preoccupied by Burmesia Healey (1908); Wunderlich (2021) coined a replacement name Burmesiana. |
| ?Burmesiola kachinensis | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A tree trunk spider. |
| Burmorchestina circular | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Oonopidae. |
| Burmorchestina prominens | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Oonopidae. |
| Burmorsolus globosus | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider, probably related to trogloraptorids. |
| Burmorsolus longembolus | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider, probably related to trogloraptorids. |
| Burmorsolus longibulbus | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider, probably related to trogloraptorids. |
| Chaeriloiurus | Gen. et sp. nov | Disputed | Lourenço in Lourenço & Velten | Cretaceous | Burmese amber | Myanmar | A scorpion belonging to the family Chaerilobuthidae or Pseudochactidae. Genus includes new species C. brigittemuellerae. Xuan et al. (2025) considered the genus Chaeriloiurus to be a junior synonym of the genus Chaerilobuthus, though the authors maintained C. brigittemuellerae as a distinct species within the latter genus. |
| Chaeriloscorpiops | Gen. et sp. nov | Valid | Lourenço in Lourenço & Velten | Cretaceous | Burmese amber | Myanmar | A scorpion belonging to the family Palaeoeuscorpiidae. Genus includes new species C. bautschi. |
| Consteniusi | Gen. et sp. nov | Valid | Downen & Selden | Eocene | Kishenehn Formation | United States | An orb-weaver spider. The type species is C. leonae. |
| Curculioides | Gen. et sp. nov | Valid | Whalen & Selden | Carboniferous (Pennsylvanian) | Energy Shale | United States | A member of Ricinulei. Genus includes new species C. bohemondi. |
| Cymbioblemma fusca | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Tetrablemmidae. |
| Cymbioblemma hamoembolus | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Tetrablemmidae. |
| Electroblemma bifurcata | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Tetrablemmidae. |
| Electroblemma caula | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Tetrablemmidae. |
| Electroblemma pinnae | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Tetrablemmidae. |
| Ellenbergellus | Gen. et sp. nov | In press | Bartel et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A member of Opiliones belonging to the family Tithaeidae. Genus includes new species E. tuberculatus. |
| Eogamasomorpha rostratis | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Tetrablemmidae. |
| Epieremulus sidorchukae | Sp. nov | In press | Arillo, Subías & Peñalver | Cretaceous | Asturian amber | Spain | A mite belonging to the group Oribatida and to the family Caleremaeidae |
| Gigantocheles | Gen. et sp. nov | In press | Bartel et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A member of Opiliones belonging to the family Epedanidae. Genus includes new species G. nilsi. |
| Gigarachne | Gen. et sp. nov | Valid | Jiang & Li in Jiang et al. | Late Cretaceous | Burmese amber | Myanmar | A spider belonging to the group Araneomorphae and to the new family Gigarachnidae. The type species is G. bian. |
| Greenwaltarachne | Gen. et sp. nov | Valid | Downen & Selden | Eocene | Kishenehn Formation | United States | An orb-weaver spider. The type species is G. pamelae. |
| Hamoderces | Gen. et sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the superfamily Scytodoidea and the family Praepholcidae. The type species is H. opilionoides. |
| Magnosegestria | Gen. et sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | Probably a tube-dwelling spider. The type species is M. tuber. |
| Mesokanus | Gen. et sp. nov | In press | Bartel et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A member of Opiliones belonging to the group Laniatores and to the new family Mesokanidae. Genus includes new species M. oehmkuehnlei. |
| Mesozomus | Gen. et sp. nov | Valid | Müller et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A member of Schizomida. Genus includes new species M. groehni. |
| Modisimus chiapanecus | Sp. nov | In press | García-Villafuerte & Valdez-Mondragón | Miocene (Aquitanian) | Mexican amber | Mexico | A species of Modisimus |
| Myannemesia | Gen. et sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to family Nemesiidae. The type species is M. glaber. |
| Myrmecarchaea antecessor | Sp. nov | | Carbuccia et al. | Eocene (Ypresian) | Oise amber | France | A member of the family Archaeidae. |
| Neophyllobius electrus | Sp. nov | Valid | Zmudzinski | Eocene | Baltic amber | Europe (Baltic Sea region) | A mite, a species of Neophyllobius. |
| Neophyllobius glaesus | Sp. nov | Valid | Zmudzinski | Eocene | Baltic amber | Europe (Baltic Sea region) | A mite, a species of Neophyllobius. |
| Odontomegops | Gen. et sp. nov | Valid | Guo et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Lagonomegopidae. Genus includes new species O. titan. |
| Odontoscirus cretacico | Sp. nov | Valid | Porta et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A mite belonging to the family Bdellidae. |
| Palaeobeloniscus | Gen. et sp. nov | In press | Bartel et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A member of Opiliones belonging to the family Beloniscidae. Genus includes new species P. thilolebi. |
| Palazarqaraneus | Gen. et sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to family Zarqaraneidae. The type species is P. hamulus. |
| Parvocteniza | Gen. et sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to family Ctenizidae. The type species is P. parvula. |
| Paurospina fastigata | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to family Zarqaraneidae. |
| Pilosarachne | Gen. et sp. nov | Valid | Jiang & Li in Jiang et al. | Late Cretaceous | Burmese amber | Myanmar | A spider belonging to the group Araneomorphae and to the new family Pilosarachnidae. The type species is P. ju. |
| Praearaneus araneoides | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Praearaneidae. |
| Priscaleclercera furcata | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Psilodercidae. |
| Priscaleclercera hamo | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Psilodercidae. |
| Priscaleclercera liber | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Psilodercidae. |
| Procheiridium | Gen. et sp. nov | Valid | Porta et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A pseudoscorpion belonging to the family Cheiridiidae and the subfamily Pycnocheiridiinae. Genus includes new species P. judsoni. |
| Propterpsiloderces crassitibia | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Eopsilodercidae. |
| Propterpsiloderces cymbioseta | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Eopsilodercidae. |
| Propterpsiloderces duplex | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Eopsilodercidae. |
| Protertheraphosa | Gen. et sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A tarantula. The type species is P. spinipes. |
| Protopyramidops | Gen. et sp. nov | In press | Bartel et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A member of Opiliones, possibly belonging to the family Pyramidopidae. Genus includes new species P. nalae. |
| Spinicreber vacuus | Sp. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Pholcochyroceridae. |
| Suraju | Gen. et sp. nov | In press | Martine et al. | Permian (Guadalupian) | Teresina Formation | Brazil | A scorpion. Genus includes new species S. itayma. |
| Unicornutiblemma | Gen. et 3 sp. et comb. nov | Valid | Wunderlich & Müller | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A spider belonging to the family Tetrablemmidae. The type species is U. gracilicornis; genus also includes new species U. brevicornis and U. longicornis, as well as "Eogamasomorpha" unicornis Wunderlich (2017). |

## Crustaceans
### Newly named taxa
#### Malacostracans

| Name | Novelty | Status | Authors | Age | Type locality | Country | Notes |
| Aliaplax | Gen. et sp. nov | Valid | Pasini et al. | Early Pleistocene | | Italy | A member of the family Goneplacidae. The type species is A. tyrsenorum. |
| Ammopylocheles romankijoki | Sp. nov | Valid | Fraaije et al. | Early Cretaceous (Berriasian) | | Czech Republic | A hermit crab belonging to the family Pylochelidae. |
| Amphoranina | Gen. et 2 sp. nov | Valid | Nyborg et al. | Eocene to Oligocene | | Canada United States | A crab belonging to the family Raninidae. Genus includes new species A. blandi and A. multispinata. |
| Ancipitecancer | Gen. et sp. nov | Valid | Pasini, Luque & Garassino | Pleistocene | | Italy | A member of Xanthoidea sensu lato, of uncertain phylogenetic placement within that group. Genus includes new species A. collinsi. |
| Angusteryon | Gen. et sp. nov | Valid | Audo & Furrer | Early Jurassic | | Switzerland | A member of Polychelida, possibly belonging to the family Coleiidae. Genus includes new species A. oberlii. |
| Annuntidiogenes sagittula | Sp. nov | Valid | Fraaije et al. | Early Cretaceous (Berriasian) | | Czech Republic | A hermit crab belonging to the family Annuntidiogenidae. |
| Bournelyreidus shiranui | Sp. nov | Valid | Ando in Ando et al. | Late Cretaceous (Cenomanian) | Enokuchi Formation | Japan | A lyreidid raninoid crab. |
| Braggitrapezia | Gen. et sp. nov | Valid | De Angeli & Caporiondo | Eocene | | Italy | A crab belonging to the group Trapezioidea. Genus includes new species B. alessandroi. |
| Caecorchestia | Gen. et sp. nov | Valid | Hegna & Lazo-Wasem in Hegna et al. | Early Miocene | Mexican amber | Mexico | A member of Amphipoda belonging to the family Talitridae. Genus includes new species C. bousfieldi. |
| Calappilia erwinhartei | Sp. nov | Valid | Wallaard et al. | Miocene (Burdigalian) | | Portugal | A species of Calappilia. |
| Callianassa reinhardpalorum | Sp. nov | Valid | Hyžný | Miocene | | Hungary Poland Slovakia | A species of Callianassa. |
| Calliax nishiki | Sp. nov | Valid | Ando et al. | Latest Pleistocene to Holocene | Moeshima Silt Bed | Japan | A member of Axiidea belonging to the family Eucalliacidae. |
| Callichirus santensis | Sp. nov | In press | Hernáez, Buchmann & Santana | Late Pleistocene | | Brazil | A species of Callichirus. |
| Cancer nancei | Sp. nov | Valid | Bahman, Feldmann & Schweitzer | Miocene | St. Marys | United States | A species of Cancer |
| Cancer zahrae | Sp. nov | Valid | Bahman, Feldmann & Schweitzer | Miocene | St. Marys | United States | A species of Cancer |
| Cherpihomola | Gen. et sp. nov | Valid | Marangon & De Angeli | Oligocene (Rupelian) | | Italy | A member of the family Homolidae. The type species is C. italica. |
| Collinscarcinus | Gen. et sp. nov | Valid | Artal & van Bakel | Eocene (Ypresian) | | Spain | A crab belonging to the family Xanthidae. Genus includes new species C. obliquesulcatus. |
| Cretacalliax | Gen. et sp. nov | Valid | Pasini, Poore & Garassino | Late Cretaceous (Cenomanian) | | Lebanon | A ghost shrimp belonging to the family Callianopsidae. Genus includes new species C. levantina. |
| Cuchiadromites | Gen. et sp. nov | In press | Ossó, van Bakel & Ferratges | Early Cretaceous (Aptian) | Patrocinio Formation | Spain | A crab belonging to the family Longodromitidae. Genus includes new species C. jadeae. |
| Daira corallina | Sp. nov | Valid | Ferratges, Zamora & Aurell | Late Eocene | | Spain | |
| Dardanus cherpionensis | Sp. nov | Valid | Marangon & De Angeli | Oligocene (Rupelian) | Ligure-Piemontese Basin | Italy | A species of Dardanus. |
| Dardanus faxensis | Sp. nov | Valid | Jakobsen et al. | Paleocene (Danian) | Faxe Formation | Denmark | A species of Dardanus. |
| Diogenes augustinus | Sp. nov | Valid | Ferratges, Zamora & Aurell | Eocene (Bartonian) | Arguis Formation | Spain | A hermit crab, a species of Diogenes. |
| Discosalaputium | Gen. et sp. nov | Valid | Schädel et al. | Late Triassic (Carnian) | Reingraben | Austria | A member of Isopoda belonging to the group Scutocoxifera. The type species is D. aschauerorum. |
| Dynomene collinsi | Sp. nov | Valid | Ossó et al. | Eocene (Priabonian) | | Spain | A crab belonging to the family Dynomenidae. |
| Eodromites bernchrisdomiorum | Sp. nov | Valid | Klompmaker et al. | Late Jurassic (Oxfordian) | | Poland | A crab belonging to the family Goniodromitidae. |
| Eodromites cristinarobinsae | Sp. nov | Valid | Klompmaker et al. | Early Cretaceous (Albian) | Eguino Formation | Spain | A crab belonging to the family Goniodromitidae. |
| Eopolycheles | Gen. et sp. nov | Valid | Gašparič et al. | Late Triassic (Carnian) | | Slovenia | A member of the family Polychelidae. Genus includes new species E. cornuaureus. |
| Eryma moriedaorum | Sp. nov | Valid | Ando et al. | Late Cretaceous (Cenomanian) | Enokuchi Formation | Japan | A member of the family Erymidae. |
| Etyus tresgalloi | Sp. nov | Valid | Ossó & Moreno-Bedmar | Early Cretaceous (Aptian) | | Spain | A crab belonging to the family Etyiidae. |
| Eupilumnus? vokesae | Sp. nov | In press | Luque in Luque et al. | Miocene | | Mexico | A crab. |
| Europrosopon | Gen. et comb. nov | Valid | Klompmaker et al. | Late Jurassic | | Austria Czech Republic Germany Romania | A crab belonging to the family Prosopidae. The type species is "Prosopon" aculeatum von Meyer (1857); genus also includes "Prosopon" abbreviatum Schweitzer & Feldmann (2009). |
| Galathea tuscia | Sp. nov | Valid | Pasini et al. | Early Pleistocene | | Italy | A species of Galathea. |
| Gammaroidorum | Gen. et sp. nov | In press | Jarzembowski et al. | Early Cretaceous (Hauterivian) | Weald | United Kingdom | A member of Amphipoda. Genus includes new species G. vonki. |
| Gelrincola | Gen. et sp. nov | Valid | Schädel et al. | Middle Triassic (Anisian) | Lower Muschelkalk Vossenveld Formation | Netherlands | A member of Isopoda belonging to the group Cymothoida. The type species is G. winterswijkensis. |
| Gemmellarocarcinus riglosensis | Sp. nov | Valid | Ferratges, Zamora & Aurell | Late Eocene | | Spain | |
| Glebocarcinus doii | Sp. nov | Valid | Karasawa & Takahashi | Early Miocene | Igami | Japan | A member of the family Cancridae |
| Graptocarcinus collinsi | Sp. nov | Valid | Vega in Vega et al. | Late Cretaceous (Maastrichtian) | Arroyo Grande Formation | Cuba | A crab belonging to the family Dynomenidae. |
| Hefriga schlechtingerae | Sp. nov | Valid | Winkler | Late Jurassic (Tithonian) | Solnhofen | Germany | A caridean shrimp |
| Hispanigalathea raymondcaseyi | Sp. nov | Valid | Van Bakel et al. | Early Cretaceous (Albian) | Gault | United Kingdom | A member of Galatheoidea. |
| Hoploparia echinata | Sp. nov | Valid | Pinheiro et al. | Late Cretaceous (Santonian–Campanian) | Santa Marta Formation | Antarctica | |
| Hoploparia hinokunika | Sp. nov | Valid | Ando & Shimada in Ando et al. | Late Cretaceous (Cenomanian) | Enokuchi Formation Karakizaki Formation | Japan | A lobster. |
| Hoploparia tectumque | Sp. nov | In press | Fraaije et al. | Late Cretaceous (Cenomanian) | | Kazakhstan | |
| Icriobranchiocarcinus rodas | Sp. nov | In press | Vega in Vega et al. | Late Cretaceous (Maastrichtian) | Arroyo Grande Formation | Cuba | A crab belonging to group Portunoidea and the family Lithophylacidae. Announced in 2020; the final version of the article naming it is scheduled to be published in 2021. |
| Joecalcinus | Gen. et sp. nov | Valid | Fraaije et al. | Eocene | | Italy | A hermit crab belonging to the family Calcinidae. Genus includes new species J. bolcensis. |
| Juranecrocarcinus | Gen. et comb. nov | In press | Van Bakel et al. | Late Jurassic (Kimmeridgian) | | Germany | A crab belonging to the family Necrocarcinidae. The type species is "Nodoprosopon" angulosum Wehner (1988). |
| Laeviprosopon musialiki | Sp. nov | Valid | Starzyk | Late Jurassic (Oxfordian) | | Poland | A crab belonging to the family Prosopidae. |
| Levashidromites | Gen. et sp. nov | In press | Van Bakel et al. | Early Cretaceous (Aptian) | Kubina Formation | Russia | A crab belonging to the family Longodromitidae. The type species is L. cornutus. |
| Lobogalenopsis joei | Sp. nov | Valid | Ferratges, Zamora & Aurell | Late Eocene | | Spain | |
| Mariaplax ohiranorikoae | Sp. nov | Valid | Karasawa and Kobayashi | Pleistocene | Atsumi Group | Japan | A member of the family Hexapodidae. |
| Marmacuma | Gen. et sp. nov | Valid | Artüz & Sakınç | Late Pleistocene | | Turkey | A member of Cumacea belonging to the family Nannastacidae. Genus includes new species M. samimei. |
| Masticacheles septemgradu | Sp. nov | Valid | Fraaije et al. | Late Jurassic (Tithonian) | | Czech Republic | A hermit crab belonging to the family Pilgrimchelidae. |
| Matutites collinsi | Sp. nov | Valid | Davis, Garassino & Weaver | Middle Eocene | Castle Hayne | United States | A member of the family Matutidae. |
| Maurocarpilius | Gen. et sp. nov | Valid | Ossó, Gagnaison & Bailleul | Eocene (Ypresian) | Ait Ouarhitane | Morocco | A member of the family Carpiliidae. The type species is M. binodosus. |
| Mesogalathea ardua | Sp. nov | Valid | Gašparič, Robins & Gale | Late Jurassic (Kimmeridgian/Tithonian) | | Slovenia | A member of the family Galatheidae. |
| Mesoparapylocheles janetjacksonae | Sp. nov | Valid | Fraaije et al. | Late Jurassic (Tithonian) | | Czech Republic | A hermit crab belonging to the family Parapylochelidae. |
| Mizuhocancer | Gen. et comb. nov | Valid | Karasawa in Karasawa & Takahashi | Early—Middle Miocene | | Japan | A member of the family Cancridae. Monotypic with the type species, Cancer? Imamurae Imaizumi, 1962. |
| Montemagrecarcinus | Gen. et sp. nov | Valid | De Angeli & Ceccon | Early Eocene | | Italy | A crab belonging to the family Pilumnidae. Genus includes new species M. efremi. |
| Moravacarcinus | Gen. et sp. nov | In press | Van Bakel et al. | Early Cretaceous (Berriasian) | Štramberk Limestone | Czech Republic | A crab belonging to the family Necrocarcinidae. The type species is M. stramberkensis. |
| Munidopsis kaedetatsuyai | Sp. nov | Valid | Karasawa | Miocene | Higashibessho Formation | Japan | A member of the family Munidopsidae. |
| Neoliomera zovoensis | Sp. nov | Valid | De Angeli & Garassino | Early Eocene | | Italy | A species of Neoliomera. |
| Nitotacarcinus ambrosii | Sp. nov | Valid | Beschin & Checchi | Eocene (Ypresian) | | Italy | A crab belonging to the superfamily Carpilioidea and the family Tumidocarcinidae. |
| Obtusotelson | Gen. et sp. nov | Valid | Schädel et al. | Late Triassic (Carnian) | Reingraben | Austria | A member of Isopoda belonging to the group Scutocoxifera. The type species is O. summesbergeri. |
| Orithyia eikii | Sp. nov | Valid | Karasawa | Early Miocene | Mizunami Group | Japan | A member of the family Orithyiidae. |
| Paguristes collinsi | Sp. nov | Valid | Marangon & De Angeli | Oligocene (Rupelian) | Ligure-Piemontese Basin | Italy | A species of Paguristes. |
| Paguristes frigoscopulus | Sp. nov | Valid | Jakobsen et al. | Paleocene (Danian) | Faxe Formation | Denmark | A species of Paguristes. |
| Paguristes joecollinsi | Sp. nov | Valid | Wallaard et al. | Miocene (Tortonian) | Pakhna Formation | Cyprus | A species of Paguristes. |
| Paguristes laurae | Sp. nov | Valid | Marangon & De Angeli | Oligocene (Rupelian) | Ligure-Piemontese Basin | Italy | A species of Paguristes. |
| Palaeopalinurellus | Gen. et 2 sp. et comb. nov | Valid | Fraaije et al. | Late Jurassic to Late Cretaceous (Cenomanian) | | Czech Republic  France  Lebanon | A furry lobster. Genus includes new species P. culocervus and P. jbeilensis, as well as "Palinurus" strambergensis Bachmayer (1959). |
| Palaeopolycheles nantosueltae | Sp. nov | | Jauvion et al. | Middle Jurassic (Callovian) | La Voulte-sur-Rhône | France | A member of Polychelida |
| Personadorippe | Gen. et 2 sp. et comb. nov | In press | Van Bakel et al. | Cretaceous (Aptian to Cenomanian) | Hudspeth Formation Kubina Formation Lyaminsk Formation | Russia United States | A crab belonging to the superfamily Dorippoidea and the family Telamonocarcinidae. The type species is P. kalashnikovi; genus also includes new species P. levashiensis, as well as "Eodorippe" connori Nyborg et al. (2019). |
| Petrolisthes landsendi | Sp. nov | Valid | Garassino & Nyborg in Garassino et al. | Late Cretaceous (Santonian) | Nanaimo Group | Canada | A species of Petrolisthes. |
| ?Proeryon erinaceus | Sp. nov | Valid | Audo, Schweigert & Charbonnier | Late Jurassic (Oxfordian) | Terrain à Chailles Formation | France | |
| ?Proeryon quiltyi | Sp. nov | Valid | Audo, Schweigert & Charbonnier | Middle Jurassic (Callovian) | | Antarctica | |
| Prosopon josephcollinsi | Sp. nov | Valid | Klompmaker et al. | Late Jurassic (Tithonian) | Ernstbrunn Limestone | Austria | A crab belonging to the family Prosopidae. |
| Protoapseudoidus | Fam. et Gen. et sp. nov | In press | Heard et al. | Early Cretaceous (Aptian) | Sierra Madre | Mexico | A member of Tanaidacea belonging to the group Apseudomorpha, in the new family Protoapseudoidae. Genus includes new species P. espinalensis. |
| Protopagurus cerebellum | Sp. nov | Valid | Fraaije et al. | Early Cretaceous (Berriasian) | | Czech Republic | A hermit crab belonging to the family Paguridae. |
| Protopagurus duopupae | Sp. nov | Valid | Fraaije et al. | Early Cretaceous (Berriasian) | | Czech Republic | A hermit crab belonging to the family Paguridae. |
| Pseudastacus lemovices | Sp. nov | Valid | Charbonnier & Audo | Early Jurassic (Sinemurian) | | France | A member of Astacidea belonging to the family Stenochiridae |
| Sabellidromites lanae | Sp. nov | Valid | Nyborg, Garassino & Ross | Late Cretaceous (late Campanian) | | Canada | A dromioid crab |
| Stenodactylina beardi | Sp. nov | Valid | Feldmann, Schweitzer & Haggart | Late Cretaceous | Haslam | Canada | A member of the family Erymidae. |
| Stenodactylina devillezi | Sp. nov | Valid | Schweigert & Härer | Late Jurassic (Kimmeridgian) | Nusplingen | Germany | A member of the family Erymidae. |
| Stenodactylina geigerae | Sp. nov | Valid | Schweigert & Härer | Late Jurassic (Tithonian) | Usseltal | Germany | A member of the family Erymidae. |
| Stonesfielderyon | Gen. et sp. nov | Valid | Audo, Schweigert & Charbonnier | Middle Jurassic (Bathonian) | | United Kingdom | A possible member of the family Eryonidae. The type species is S. imitator. |
| Tanidromites nightwishorum | Sp. nov | Valid | Klompmaker et al. | Late Jurassic (Tithonian) | Ernstbrunn Limestone | Austria | A crab belonging to the family Tanidromitidae. |
| Tanidromites weinschenki | Sp. nov | Valid | Klompmaker et al. | Late Jurassic (Kimmeridgian) | Oberjura-Massenkalk Formation | Germany | A crab belonging to the family Tanidromitidae. |
| Tymolus bottemilleri | Sp. nov | Valid | Nyborg & Garassino | Miocene | Astoria | United States | A crab belonging to the family Cyclodorippidae. |
| Tymolus collinsi | Sp. nov | Valid | Nyborg & Garassino | Miocene | | United States | A crab belonging to the family Cyclodorippidae. |
| Upogebia azorensis | Sp. nov | Valid | Hyžný in Hyžný et al. | Pliocene | | Azores | A species of Upogebia. Announced in 2020; the final version of the article naming it was published in 2021. |
| Vecticallichirus kawanoi | Sp. nov | Valid | Ando | Late Eocene | Funazu | Japan | A ghost shrimp belonging to the family Callichiridae. |
| Vectis collinsi | Sp. nov | In press | Van Bakel et al. | Early Cretaceous (Aptian) | Kubina Formation | Russia | A crab belonging to the family Viaiidae. |

#### Ostracods

| Name | Novelty | Status | Authors | Age | Type locality | Country | Notes |
| Adelphobolbina praeclara | Sp. nov | Valid | Becker, Braun & Pratt | Devonian | | Canada | |
| Ampuloides beckeri | Sp. nov | Valid | Nazik et al. | Late Devonian | | Mongolia | A member of Podocopida belonging to the superfamily Bairdiocypridoidea and the family Pachydomellidae. |
| Angarallina | Gen. et 2 sp. nov | Valid | Melnikova | Ordovician | | Russia | Genus includes new species A. demissa and A. aenigma. |
| Araxobairdia | Gen. et sp. nov | Valid | Gliwa in Gliwa et al. | Permian (Changhsingian) | | Iran | A member of Podocopida belonging to the family Bairdiidae. The type species is A. formosa. |
| Bairdia andrecrasquini | Sp. nov | | Crasquin et al. | Late Triassic | | Italy | A member of the family Bairdiidae. |
| Bairdia gambaneraensis | Sp. nov | | Crasquin et al. | Late Triassic | | Italy | A member of the family Bairdiidae. |
| Bairdia paramolesta | Sp. nov | Valid | Cabral, Lord & Pinto in Cabral et al. | Early Jurassic (Pliensbachian and Toarcian) | | Portugal | A member of the family Bairdiidae. |
| Bairdiacypris argonautaii | Sp. nov | Valid | Forel in Forel & Grădinaru | Late Triassic (Rhaetian) | Kössen Formation | Austria Romania | A member of Podocopida belonging to the family Bairdiidae. |
| Bairdiacypris kathleenae | Sp. nov | Valid | Gliwa in Gliwa et al. | Late Permian and Early Triassic (Changhsingian–Griesbachian) | | Iran | A member of Podocopida belonging to the family Bairdiidae. |
| Beyrichiopsis hushootensis | Sp. nov | Valid | Nazik et al. | Late Devonian | | Mongolia | A member of Platycopida belonging to the superfamily Kloedenelloidea and the family Beyrichiopsidae. |
| Bythocypris dorsogibba | Sp. nov | In press | Trabelsi et al. | Early Cretaceous (Albian) | Orbata | Tunisia | |
| Bythocypris? multagracilis | Sp. nov | In press | Trabelsi et al. | Early Cretaceous (Albian) | Orbata | Tunisia | |
| Bythocypris? pythagorasi | Sp. nov | In press | Trabelsi et al. | Early Cretaceous (Aptian) | Orbata | Tunisia | |
| Candonopsis carthaginensis | Sp. nov | In press | Trabelsi et al. | Early Cretaceous (Albian) | Orbata | Tunisia | |
| Capsacythere baldanzae | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Capsacythere fekihi | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Capsacythere giovannae | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Capsacythere salaji | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Carinaknightina hofmanni | Sp. nov | Valid | Gliwa in Gliwa et al. | Permian (Changhsingian) | | Iran | A member of Palaeocopida belonging to the family Kirkbyidae. |
| Cavellina fosteri | Sp. nov | Valid | Gliwa in Gliwa et al. | Permian (Changhsingian) | | Iran | A member of Platycopida belonging to the family Cavellinidae. |
| Cavellina hairapetiani | Sp. nov | Valid | Gliwa in Gliwa et al. | Permian (Changhsingian) | | Iran | A member of Platycopida belonging to the family Cavellinidae. |
| Ceratobairdia? akhilleus | Sp. nov | Valid | Forel in Forel & Grădinaru | Late Triassic (Rhaetian) | | Romania | A member of Podocopida belonging to the family Bairdiidae. |
| Chrysocythere arutai | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Chrysocythere gliozziae | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Chrysocythere russoi | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Cimbaurila maamourii | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Hemicytheridae. |
| Costa ponticulocarinata | Sp. nov | Valid | Yasuhara et al. | Early Miocene | | India | |
| Costoprimites multicostatus | Sp. nov | Valid | Gonta | Ordovician | | Russia | |
| Costoprimites processus | Sp. nov | Valid | Gonta | Ordovician | | Russia | |
| Cypridea punctacentralis | Sp. nov | In press | Santos Filho, Fauth & Sames | Early Cretaceous | Orós Formation | Brazil | |
| Cytherella ilariae | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A species of Cytherella. |
| Cytheretta mariaantoniettae | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Cytherettidae. |
| Dicerobairdia buseri | Sp. nov | Valid | Forel in Forel, Kolar-Jurkovšek & Jurkovšek | Late Triassic (Carnian) | | Slovenia | A member of Podocopida belonging to the family Bairdiidae. |
| Direigina | Gen. et sp. nov | Valid | Melnikova | Ordovician | | Russia | Genus includes new species D. nana. |
| Disulcina proxima | Sp. nov | Valid | Melnikova | Ordovician | | Russia | A member of the family Tetradellidae. |
| Dolocythere amphistiela | Sp. nov | Valid | Lord, Cabral & Danielopol | Early Cretaceous (Albian) | | Germany | A member of Podocopida belonging to the family Cytheridae |
| Dolocytheridea donzei | Sp. nov | In press | Trabelsi et al. | Early Cretaceous (Albian) | Orbata | Tunisia | |
| Dorsogibbella alium | Sp. nov | Valid | Gonta | Ordovician | | Russia | |
| Dorukella crasquinae | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Hemicytheridae. |
| Dorukella nevioi | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Hemicytheridae. |
| Dorukella razgallahae | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Hemicytheridae. |
| Dorukella ruggeroi | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Hemicytheridae. |
| Eumiraculum mettei | Sp. nov | Valid | Gliwa in Gliwa et al. | Permian (Wuchiapingian–Changhsingian) | | Iran | A member of Podocopida belonging to the superfamily Bairdioidea. |
| Fabalicypris veronicae | Sp. nov | Valid | Gliwa in Gliwa et al. | Permian (Changhsingian) | | Iran | A member of Podocopida belonging to the family Bairdiidae. |
| Foramenella sibirica | Sp. nov | Valid | Melnikova | Ordovician | | Russia | |
| Graptocythere octopus | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Hemicytheridae. |
| Hallatina oblonga | Sp. nov | Valid | Melnikova | Ordovician | | Russia | A member of the group Leperditellocopida belonging to the family Primitiidae. |
| Hastacypris | Gen. et sp. nov | Junior homonym | Santos Filho, Fauth & Sames | Early Cretaceous | Orós Formation | Brazil | A member of Cypridoidea. Genus includes new species H. adamantem. The generic name is preoccupied by Hastacypris Croneis & Gutke (1939); Guillam (2024) coined a replacement name Cuspicypris. |
| Heterocypris aspirasensis | Sp. nov | Valid | Durak, Akkiraz & Nazik | Early Miocene | Aspiras Basin | Turkey | A species of Heterocypris. Announced in 2020; the final version of the article naming it was published in 2021. |
| Histriabairdia | Gen. et sp. et comb. nov | Valid | Forel in Forel & Grădinaru | Late Triassic (Carnian) to Middle Jurassic (Bathonian) | | Austria France Germany India Italy Romania Switzerland | A member of Podocopida belonging to the family Bairdiidae. The type species is H. pontuseuxinusensis; genus also includes "Anchistrocheles"? spinosa Sheppard in Brand (1990), "Anchistrocheles"? tuningensis Beher (2004) and "Anchistrocheles" gemmellaroi Crasquin in Crasquin et al. (2018). |
| Hungarella forelae | Sp. nov | | Crasquin et al. | Late Triassic | | Italy | A member of the family Healdiidae. |
| Hungarella siciliiensis | Sp. nov | | Crasquin et al. | Late Triassic | | Italy | A member of the family Healdiidae. |
| Hungaroleberis striatus | Sp. nov | Valid | Gliwa in Gliwa et al. | Permian (Changhsingian) | | Iran | A member of Myodocopida belonging to the family Cylindroleberididae. |
| Illativella triquetra | Sp. nov | Valid | Becker, Braun & Pratt | Devonian | | Canada | |
| Ilyocypris? arca | Sp. nov | In press | Santos Filho, Fauth & Sames | Early Cretaceous | Orós Formation | Brazil | |
| Ilyocypris? latanodi | Sp. nov | In press | Santos Filho, Fauth & Sames | Early Cretaceous | Orós Formation | Brazil | |
| Isobythocypris atalantella | Sp. nov | Valid | Forel in Forel & Grădinaru | Late Triassic (Rhaetian) | | Romania | A member of Podocopida belonging to the family Bairdiidae. |
| Jonesites chunensis | Sp. nov | Valid | Gonta | Ordovician | | Russia | |
| Kerocythere dittainoensis | Sp. nov | | Crasquin et al. | Late Triassic | | Italy | A member of the family Cytheruridae. |
| Kiesowia (?) incerta | Sp. nov | Valid | Melnikova | Ordovician | | Russia | A member of the family Ctenonotellidae. |
| Kinkelinella ventrocarinata | Sp. nov | Valid | Cabral, Pinto & Lord in Cabral et al. | Early Jurassic (Toarcian) | | Portugal United Kingdom | A member of the family Protocytheridae. |
| Kinnekullea gaia | Sp. nov | Valid | Hearing et al. | Ordovician (Katian) | Phu Ngu | Vietnam | |
| Korolyukina | Gen. et 2 sp. nov | Valid | Melnikova | Ordovician | | Russia | A member of the family Bolliidae. Genus includes new species K. conspicua and K. taimyrica. |
| Laccochilina (?) jugata | Sp. nov | Valid | Melnikova | Ordovician | | Russia | A member of the family Eurychilinidae. |
| Laccochilina (Prochilina) yanpingensis | Sp. nov | In press | Zhang | Ordovician | Shihtzupu Formation | China | |
| Leucocytherella dangeloi | Sp. nov | Valid | Alivernini in Alivernini et al. | Miocene (Messinian) and Pliocene | Zhada Basin | China | A member of the family Limnocytheridae. |
| Liuzhinia julfensis | Sp. nov | Valid | Gliwa in Gliwa et al. | Late Permian and Early Triassic (Changhsingian–Griesbachian) | | Iran | A member of Podocopida belonging to the superfamily Bairdioidea. |
| Lyumellina | Gen. et sp. nov | Valid | Gonta | Ordovician | | Russia | Genus includes new species L. risus |
| Minyocythere | Gen. et 2 sp. et comb. nov | Valid | Lord, Cabral & Danielopol | Middle Jurassic (Aalenian and Bajocian) | | Germany  Netherlands  United Kingdom | A cytherid Podocopida. The type species is M. macroporosa; genus also includes new species M. angulata, as well as "Dolocythere" maculosa Bate (1963) and "Dolocythere" tuberculata Luppold (2012). |
| Mockella barbroae | Sp. nov | | Crasquin et al. | Late Triassic | | Italy | A member of the family Limnocytheridae. |
| Mongolianella kyranbeki | Sp. nov | In press | Choi et al. | Cretaceous | Yanji | China | |
| Myanmarcypris | Gen. et sp. nov | Valid | Wang et al. | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A member of the family Candonidae belonging to the subfamily Paracypridinae. Genus includes new species M. hui. |
| Nikolina entonipteros | Sp. nov | Valid | Gonta | Ordovician | | Russia | |
| Nikolina pteroventralis | Sp. nov | Valid | Gonta | Ordovician | | Russia | |
| Okadaleberis (?) benzartiae | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Okadaleberis decimai | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Okadaleberis guerneti | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Okadaleberis hendae | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Okadaleberis khayatii | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Okadaleberis memmiae | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Trachyleberididae. |
| Orthobairdia capuliformis | Sp. nov | Valid | Gliwa in Gliwa et al. | Permian (Changhsingian) | | Iran | A member of Podocopida belonging to the family Bairdiidae. |
| Paijenborchellina reitanoi | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Cytheridae. |
| Paractinocythereis | Gen. et comb. nov | Valid | Yasuhara et al. | Early Miocene | | India | A new genus for "Actinocythereis" gujaratensis Tewari & Tandon (1960) |
| Paracypris chekhmai | Sp. nov | In press | Trabelsi et al. | Early Cretaceous (Aptian) | Orbata | Tunisia | |
| Paracypris ovidi | Sp. nov | Valid | Forel in Forel & Grădinaru | Late Triassic (Rhaetian) | | Romania | A member of Cypridoidea belonging to the family Paracyprididae. |
| Perissocytheridea altesulcata | Sp. nov | In press | Trabelsi et al. | Early Cretaceous (Aptian) | Orbata | Tunisia | |
| Perissocytheridea kouminiensis | Sp. nov | In press | Trabelsi et al. | Early Cretaceous (Albian) | Orbata | Tunisia | |
| Petasobairdia amazonella | Sp. nov | Valid | Forel in Forel & Grădinaru | Late Triassic (Rhaetian) | | Romania | A member of the family Bairdiidae. |
| Petasobairdia jeandercourti | Sp. nov | | Crasquin et al. | Late Triassic | | Italy | A member of the family Bairdiidae. |
| Pontocypris? karavankensis | Sp. nov | Valid | Forel in Forel, Kolar-Jurkovšek & Jurkovšek | Late Triassic (Carnian) | | Slovenia | A member of Cypridoidea belonging to the family Pontocyprididae. |
| Postsinusella | Gen. et sp. nov | Valid | Gonta | Ordovician | | Russia | Genus includes new species P. guttaformis. |
| Prasuchonella? huarpe | Sp. nov | Valid | Carignano, Echevarría & Zavattieri | Middle Triassic | Cuyo Basin | Argentina | A member of Darwinulocopina. |
| Pseudoleperditia? vetusta | Sp. nov | Valid | Becker, Braun & Pratt | Devonian | | Canada | |
| Pseudomacrocypris? kerabani | Sp. nov | Valid | Forel in Forel & Grădinaru | Late Triassic (Rhaetian) | | Romania | A member of Cypridoidea belonging to the family Pontocyprididae. |
| Pseudulrichia replicata | Sp. nov | Valid | Melnikova | Ordovician | | Russia | A member of the family Richinidae. |
| Ptychobairdia iudicaensis | Sp. nov | | Crasquin et al. | Late Triassic | | Italy | A member of the family Bairdiidae. |
| Ptychobairdia leonardoi | Sp. nov | | Crasquin et al. | Late Triassic | | Italy | A member of the family Bairdiidae. |
| Pythagoracypris | Gen. et sp. nov | In press | Santos Filho, Fauth & Sames | Early Cretaceous | Orós Formation | Brazil | Genus includes new species P. latavectis. |
| Rhinocypris? ericius | Sp. nov | In press | Santos Filho, Fauth & Sames | Early Cretaceous | Orós Formation | Brazil | |
| Ruggieria quadricarinata | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Cytherettidae. |
| Steusloffia rudiformis | Sp. nov | Valid | Gonta | Ordovician | | Russia | |
| Sulcicuneus gemmifer | Sp. nov | Valid | Becker, Braun & Pratt | Devonian | | Canada | |
| Tasmanocypris lochardi | Sp. nov | In press | Warne | Late Miocene and Pliocene | | Australia | |
| Tesakovites | Gen. et sp. nov | Valid | Melnikova | Ordovician | | Russia | A member of the family Circulinidae. Genus includes new species T. rotundatus. |
| Urftella triangula | Sp. nov | Valid | Becker, Braun & Pratt | Devonian | | Canada | |
| Urocythere (Pokornyella) salaktaensis | Sp. nov | In press | Sciuto & Temani in Sciuto, Temani & Ammar | Miocene (Messinian) | | Tunisia | A member of Podocopa belonging to the family Hemicytheridae. |
| Velatomorpha rochacamposi | Sp. nov | Valid | Bergue, Maranhao & Ng | Permian | | Brazil | |

#### Other crustaceans

| Name | Novelty | Status | Authors | Age | Type locality | Country | Notes |
| Actinobalanus? sloveniensis | Sp. nov | Valid | Buckeridge et al. | Oligocene and Miocene | | Slovenia | A barnacle. |
| Altiverruca capsa | Sp. nov | Valid | Gale | Pliocene-early Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Verrucidae. |
| Altiverruca fusione | Sp. nov | Valid | Gale | Pliocene-early Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Verrucidae. |
| Ambocyclus | Gen. et comb. nov | Valid | Schweitzer, Mychko & Feldmann | Carboniferous | | Ireland  Russia  United States? | A member of Cyclida. Genus includes A. capidulum (Chernyschev, 1933), A. simulans (Reed, 1908) and possibly A. ? minutus (Rogers, 1902). |
| Angulotergum kiamichensis | Sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. |
| Angulotergum milviformis | Sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. |
| Angulotergum robustum | Sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. |
| Arcoscalpellum s.l. isaonishikawai | Sp. nov | Valid | Karasawa | Miocene | Katsuta Group | Japan | A member of the family Scalpellidae. |
| Arcoscalpellum s.l. Joei | Sp. nov | Valid | Karasawa | Miocene | Yotsuyaku Formation | Japan | A member of the family Scalpellidae. |
| Arcuatoscalpellum wacoensis | Sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. |
| Ashinkailepas indica | Sp. nov | Valid | Gale in Gale et al. | Late Pleistocene | | India | A barnacle |
| Aurivillialepas mascarensis | Sp. nov | Valid | Gale | Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Calanticidae. |
| Brachylepas hantonensis | Sp. nov | Valid | Gale | Cretaceous | | United Kingdom | A barnacle |
| Brachylepas thieli | Sp. nov | Valid | Gale | Cretaceous | | Germany | A barnacle |
| Brittaniclus | Gen. et comb. nov | Valid | Schweitzer, Mychko & Feldmann | Carboniferous | | United Kingdom | A member of Cyclida belonging to the family Americlidae. Genus includes B. rankini (Woodward, 1868), B. scotti (Woodward, 1894) and B. testudo (Peach, 1882). |
| Carabicyclus | Gen. et comb. nov | Valid | Schweitzer, Mychko & Feldmann | Carboniferous | | Ireland  United Kingdom | A member of Cyclida. Genus includes C. wrighti (Woodward, 1870). |
| Catherinum busselli | Sp. nov | Valid | Gale | Pliocene-early Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Scalpellidae. |
| Chernyshevine | Gen. et comb. nov | Valid | Schweitzer, Mychko & Feldmann | Carboniferous | | Tajikistan | A member of Cyclida. Genus includes C. spinosus (Chernyschev, 1933). |
| Collinslepas | Gen. et 3 sp. nov | Valid | Gale | Cretaceous | | Morocco Tunisia | A barnacle. Genus includes new species C. aitlaminensis, C. robustus and C. tunisiensis. |
| Costatolepas | Gen. et sp. nov | Valid | Gale | Pliocene-early Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Scalpellidae. The type species is C. buckeridgei. |
| Costatoverruca baxteri | Sp. nov | Valid | Gale | Pliocene-early Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Verrucidae. |
| Costatoverruca macropluteum | Sp. nov | Valid | Gale | Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Verrucidae. |
| Costatoverruca tredecima | Sp. nov | Valid | Gale | Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Verrucidae. |
| Cretiscalpellum robaszynskii | Sp. nov | In press | Gale, Jagt & Goolaerts | Late Cretaceous (Maastrichtian) | | Tunisia | A barnacle. |
| Daohugounaias | Gen. et sp. nov | Valid | Luo et al. | Middle Jurassic | Daohugou | China | A member of Anostraca. Genus includes new species D. cheni. |
| Diotascalpellum acies | Sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. |
| Dziklus | Gen. et comb. nov | Valid | Schweitzer, Mychko & Feldmann | Carboniferous | Mazon Creek fossil beds | United States | A member of Cyclida belonging to the family Americlidae. Genus includes D. obesus (Schram, Vonk & Hof, 1997). |
| Eoverruca aubensis | Sp. nov | Valid | Gale | Early Cretaceous (Albian) | | France | A barnacle |
| Eoverruca symmetrica | Sp. nov | Valid | Gale | Late Cretaceous (Campanian) | | United Kingdom | A barnacle |
| Etcheslepas portlandensis | Sp. nov | Valid | Gale | Tithonian–Berriasian | Portland Group | United Kingdom | A barnacle |
| Fallaxlepas | Gen. et comb. nov | Valid | Gale | Cretaceous | | United Kingdom | A brachylepadid barnacle. The type species is "Pollicipes" fallax Darwin (1851) |
| Gibbosaverruca youngi | Sp. nov | Valid | Gale | Pliocene-early Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Verrucidae. |
| Iliestheria urumqiensis | Sp. nov | Valid | Teng & Li | Early Jurassic (Pliensbachian–Toarcian) | Sangonghe | China | A clam shrimp. Announced in 2020; the final version of the article naming was published in 2021. |
| Ivolepas worthensis | Sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. |
| Jagtscalpellum | Gen. et comb. et 3 sp. nov | Valid | Gale | Cretaceous | | Tunisia United Kingdom United States | A barnacle. The type species is "Pollicipes" striatus Darwin (1851); genus also includes "Pollicipes" filosus Withers (1911), as well as new species J. africanum, J. spinosum and J. luteorum. |
| Lahuerguinagrapta | Gen. et sp. nov | In press | Gallego et al. | Early Cretaceous | La Huérguina | Spain | An afrograptid clam shrimp. Genus includes new species L. multicostata. |
| Litocyclus | Gen. et comb. nov | Valid | Schweitzer, Mychko & Feldmann | Carboniferous | | Ireland  United Kingdom  United States? | A member of Cyclida. Genus includes L. bilobatus (Woodward, 1870), L. jonesianus (Woodward, 1870), L. torosus (Woodward, 1870) and possibly also L. ? communis (Rogers, 1902) and L. ? permarginatus (Rogers, 1902). |
| Lophobalanus fresvillensis | Sp. nov | Valid | Gale | Eocene (Lutetian) | | France | A barnacle. Announced in 2020; the final version of the article naming it was published in 2021. |
| Loriculina fragila | Sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. |
| Loriculina rubrifluvia | Sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. |
| Loriolepas whytei | Sp. nov | Valid | Gale | Tithonian–Berriasian | | United Kingdom | A barnacle |
| Newmaniverruca multitabulata | Sp. nov | Valid | Gale | Pliocene-early Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Verrucidae. |
| Pachylasma traceyi | Sp. nov | Valid | Gale | Pliocene-Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Pachylasmatidae. |
| Proverruca anglica | Sp. nov | Valid | Gale | Cretaceous | | United Kingdom | A barnacle |
| Regioscalpellum kennedyi | Sp. nov | Valid | Gale | Cretaceous | | Tunisia | A barnacle |
| Rostratoverruca darwini | Sp. nov | Valid | Gale | Pliocene-early Pleistocene | | Indian Ocean (Mascarene Plateau) | A barnacle belonging to the family Verrucidae. |
| Striascalpellum | Gen. et 3 sp. et comb. nov | Valid | Gale | Cretaceous | | Sweden United Kingdom | A barnacle. The type species is S. elegans; genus also includes new species S. bromleyi and S. barringtonensis, as well as "Scalpellum (Titanolepas)" martini Withers (1935). |
| Subsecolepas | Gen. et sp. nov | Valid | Gale | Cretaceous | | United Kingdom | A barnacle. The type species is S. holtwilsoni. |
| Tazawacyclus | Gen. et comb. nov | Valid | Schweitzer, Mychko & Feldmann | Carboniferous | | Japan | A member of Cyclida. Genus includes T. tazawai (Niko & Ibaraki, 2011). |
| Texaslepas | Gen. et sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. Genus includes new species T. holterhoffi. |
| Vectibalanus | Gen. et comb. et sp. nov | Valid | Gale | Eocene and Oligocene | Barton Bouldnor Headon Hill Selsey | United Kingdom | A barnacle. The type species is "Balanus" unguiformis Sowerby (1846); genus also includes "Balanus" erisma Sowerby (1846) and a new species V. mortoni. Announced in 2020; the final version of the article naming it was published in 2021. |
| Virgilepas | Gen. et 3 sp. nov | Valid | Gale | Cretaceous | | Morocco United Kingdom | A barnacle. Genus includes new species V. aboudaensis, V. peakei and V. hancocki. |
| Virgiscalpellum laevis | Sp. nov | Valid | Gale | Cretaceous | | United Kingdom | A barnacle |
| Virgiscalpellum marysensis | Sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. |
| Virgiscalpellum mhrilensis | Sp. nov | Valid | Gale | Cretaceous | | Tunisia | A barnacle |
| Virgiscalpellum multilineatum | Sp. nov | Valid | Gale | Cretaceous | | Tunisia | A barnacle |
| Virgiscalpellum rugosum | Sp. nov | In press | Gale | Cretaceous | | United States | A barnacle. |
| Virgiscalpellum sussexiense | Sp. nov | Valid | Gale | Cretaceous | | United Kingdom | A barnacle |
| Virgiscalpellum truncatum | Sp. nov | Valid | Gale | Cretaceous | | United Kingdom | A barnacle |
| Witherscalpellum | Gen. et comb. nov | Valid | Gale | Cretaceous | | France  United Kingdom | A barnacle. The type species is "Cretiscalpellum aptiensis Withers (1935); genus also includes "Cretiscalpellum" matrioni Gale (2019). |

### General research

* Redescription and a study on the phylogenetic relationships of Francocaris grimmi, based on data from new fossil material from the Solnhofen Limestone (Germany), is published by Pazinato et al. (2020).
* A hermit crab belonging to the family Pylochelidae preserved in a shell of an ammonite belonging to the species Craspedites nekrassovi will be described from the Upper Jurassic of Moscow, Russia by Mironenko (2020).
* A putative lobster Tricarina gadvanensis from the Early Cretaceous of Iran is reinterpreted as a seroloid isopod by Hyžný et al. (2020).
* A study on the phylogenetic relationships of Eocarcinus praecursor is published by Scholtz (2020).
* A study on anatomical adaptations that enabled an ecological transition into the water column in Silurian myodocopes, focusing on myodocopids from the Herefordshire Lagerstätte (United Kingdom), is published by Siveter, Perrier & Williams (2020).
* A study comparing sexual dimorphism in ostracods from the Gulf and Atlantic coastal plain before and after the Cretaceous–Paleogene extinction event is published by Martins et al. (2020).
* Redescription of Americlus rankini and a study on the paleoecology of this taxon is published by Clark et al. (2020).

## Trilobites
### New taxa

| Name | Novelty | Status | Authors | Age | Type locality | Country | Notes |
| Acastoides biebrichensis | Sp. nov | Valid | Alberti | Devonian (Emsian) | Rupbach Shale | Germany | A member of the family Acastidae. |
| Acastoides requadti | Sp. nov | Valid | Alberti | Devonian (Emsian) | Rupbach Shale | Germany | A member of the family Acastidae. |
| Aciculolenus askewi | Sp. nov | Valid | Chatterton | Cambrian (Jiangshanian) | | Canada | |
| Arduennella hainauensis | Sp. nov | Valid | Van Viersen & Alberti | Devonian (Emsian) | | Germany | |
| Atlanticalymene | Gen. et sp. nov | Valid | Adrain, Karim & McAdams | Ordovician (Darriwilian) | Table Cove Formation | Canada | A calymenine trilobite. The type species is A. bardensis. |
| Balvibole | Gen. et sp. nov | Valid | Basse & Lemke | Devonian (Famennian) | Dasberg Limestone | Germany | A cyrtosymboline trilobite. Genus includes new species B. kaufmanni. |
| Blountia angelae | Sp. nov | Valid | Armstrong, Westrop & Eoff | Cambrian | Nolichucky Formation | United States | A member of the family Kingstoniidae. |
| Blountia morgancreekensis | Sp. nov | Valid | Armstrong, Westrop & Eoff | Cambrian | Riley Formation | United States | A member of the family Kingstoniidae. |
| Blountia nevadensis | Sp. nov | Valid | Armstrong, Westrop & Eoff | Cambrian | Mendha Formation | United States | A member of the family Kingstoniidae. |
| Blountia newfoundlandensis | Sp. nov | Valid | Armstrong, Westrop & Eoff | Cambrian | Shallow Bay Formation | Canada | A member of the family Kingstoniidae. |
| Blountia tennesseensis | Sp. nov | Valid | Armstrong, Westrop & Eoff | Cambrian | Nolichucky Formation | United States | A member of the family Kingstoniidae. |
| Boethiusia | Gen. et comb. nov | Valid | Geyer | Cambrian | | Italy | A new genus for "Dolerolenus" courtessolei Pillola (1991). |
| Clappaspis tupeq | Sp. nov | Valid | Peel | Cambrian (Miaolingian) | Telt Bugt Formation | Greenland | A member of the family Alokistocaridae. |
| Cliffia nicoleae | Sp. nov | Valid | Chatterton | Cambrian (Jiangshanian) | | Canada | |
| Cyphaspides paulospinatus | Sp. nov | Valid | Alberti | Devonian | | Germany | A member of Proetida belonging to the family Aulacopleuridae. |
| Cyphaspides speculator | Sp. nov | Valid | Alberti | Devonian | | Germany | A member of Proetida belonging to the family Aulacopleuridae. |
| Dicranurus webbyi | Sp. nov | Valid | Holloway, Smith & Thomas | Ordovician (Katian) | Gunningbland Formation | Australia | An odontopleurid trilobite. |
| Ehmaniella sermersuaqensis | Sp. nov | Valid | Peel | Cambrian (Miaolingian) | Telt Bugt Formation | Greenland | A member of the family Alokistocaridae. |
| Elrathia hensonensis | Nom. nov | Valid | Geyer & Peel | Cambrian | Ekspedition Bræ Formation | Greenland | A replacement name for Elrathia groenlandica Geyer & Peel (2017). |
| Eowinterbergia effenbergensis | Sp. nov | Valid | Basse & Lemke | Devonian (Famennian) | Wocklum Limestone | Germany | |
| Epicurella | Gen. et sp. nov | Valid | Geyer | Cambrian | | Morocco | A member of the family Despujolsiidae. Genus includes new species E. pustulata. |
| Feistops | Gen. et 2 sp. nov | Valid | Crônier et al. | Devonian (Famennian) | | Mongolia | A phacopid trilobite. Genus includes new species F. mongoliensis and F. khovdensis. Announced in 2020; the final version of the article naming was published in 2021. |
| Gravicalymene bakeri | Sp. nov | In press | Smith & Ebach | Ordovician (Katian) | Gordon Group | Australia | A calymenid trilobite. |
| ?Houseops olonbulagensis | Sp. nov | Valid | Crônier et al. | Devonian (Famennian) | | Mongolia | A phacopid trilobite. Announced in 2020; the final version of the article naming was published in 2021. |
| Kingaspidoides spinirecurvatus | Sp. nov | Valid | Geyer, Pais & Wotte | Cambrian | Jbel Wawrmast Formation | Morocco | A member of Redlichiida belonging to the family Ellipsocephalidae. |
| Marsaisia devoillei | Sp. nov | Valid | Geyer | Cambrian | | Morocco | A member of the family Despujolsiidae. |
| Marsaisia? lemdadensis | Sp. nov | Valid | Geyer | Cambrian | | Morocco | A member of the family Despujolsiidae. |
| Phantaspis | Gen. et sp. nov | Valid | Sun, Zeng & Zhao | Cambrian (Wuliuan) | Mantou Formation | China | A member of Ptychopariacea of uncertain phylogenetic placement. The type species is P. auritus. |
| Proabadiella | Gen. et 2 sp. nov | Valid | Liñán et al. | Cambrian Stage 3 | Pusa Formation | Spain | Genus includes new species P. toletana and P. vidalii. |
| Prophalaron | Gen. et sp. nov | Valid | Holloway, Smith & Thomas | Ordovician (Katian) | Gunningbland Formation | Australia | A calymenid trilobite. Genus includes new species P. jonesi. |
| Prosaukia oculata | Sp. nov | Valid | Wernette et al. | Cambrian (Furongian) | Ao Mo Lae Formation | Thailand | |
| Satunarcus | Gen. et sp. nov | Valid | Wernette et al. | Late Cambrian | Ao Mo Lae Formation | Thailand | A kaolishaniid trilobite belonging to the new subfamily Ceronocarinae. Genus includes new species S. molaensis. |
| Saukianda? dresnayi | Sp. nov | In press | Geyer & Landing | Cambrian | | Moroccan‒Algerian border region | |
| Treveropyge hellemondi | Sp. nov | Valid | Van Viersen & Taghon | Devonian (Emsian) | Our Formation | Belgium | A member of the family Acastidae. |
| Utia debra | Sp. nov | Valid | Sundberg | Cambrian (Wuliuan) | Lakeview Limestone Spence Shale | United States | A member of Ptychopariida belonging to the family Utiidae. |

### General research

* A study on the timing of the trilobite extinctions at the early to middle Cambrian transition is published by Sundberg et al. (2020).
* Evidence of gregarious moulting of Cambrian (Stage 4) trilobites from the "Tsinghsutung" Formation (China), representing one of the earliest records of synchronized moulting behaviours in the fossil record, is presented by Corrales-García et al. (2020).
* A study on trilobite size variations in the Ordovician Fezouata Formation (Morocco) deposited in a cold-water environment is published by Saleh et al. (2020).
* A study on the nature of variation among oryctocephalid specimens from the Combined Metals Member of the Pioche Formation (Nevada; Cambrian Stage 4) will be published by Webster & Sundberg (2020).
* A study on the ontogeny of the olenid trilobite Leptoplastides salteri is published by Månsson & Clarkson (2020).
* A study on the anatomy of the internal structures of the compound eye of Aulacopleura koninckii is published by Schoenemann & Clarkson (2020).
* A study on exuviae of Ovalocephalus tetrasulcatus from the Ordovician Linhsiang Formation (Hubei, China) is published by Zong (2020), who reports exuviae arranged with two or three together end to end or superimposed, and evaluates the implications of these findings for the knowledge of the behavior of trilobites.

## Other arthropods
### Newly named taxa

| Name | Novelty | Status | Authors | Age | Type locality | Country | Notes | Images |
| Adelophthalmus pyrrhae | Sp. nov | Valid | Lamsdell et al. | Carboniferous (Tournaisian) | St. Nazaire Group (possibly Lydiennes Formation) | France | A eurypterid. | |
| Allolimulus | Gen. et comb. nov | Disputed | Lamsdell | Jurassic | | United Kingdom | A horseshoe crab. The type species is "Limulus" woodwardi Watson (1909). However, Bicknell et al. (2021) transferred "L." woodwardi to the genus Mesolimulus. | (A) Norilimulus woodae, (B) Batracholimulus fuchsbergensis, (C) Boeotiaspis longispinus, (D) Keuperlimulis vicensis, (E) Volanalimulus madagascarensis, (F) Allolimulus woodwardi |
| Andersoniella | Gen. et comb. nov | Valid | Lamsdell | Carboniferous | | Germany  United States | A member of the family Belinuridae. The type species is "Euproops" longispina Packard (1885). | |
| Batracholimulus | Gen. et comb. nov | Valid | Lamsdell | Triassic | | Germany | A member of the family Austrolimulidae. The type species is "Paleolimulus" fuchsbergensis Hauschke & Wilde (1987). | |
| Boeotiaspis | Gen. et comb. nov | Valid | Lamsdell | Carboniferous | | United States | A member of the family Austrolimulidae. The type species is "Paleolimulus" longispinus Schram (1979). | |
| Bushizheia | Gen. et sp. nov | Valid | O'Flynn & Liu in O'Flynn et al. | Cambrian Stage 3 | Chiungchussu | China | An early euarthropod of uncertain phylogenetic placement. The type species is B. yangi. | |
| Concavicaris martinae | Sp. nov | Valid | Broda, Rak & Hegna | Devonian (Famennian) | | Czech Republic | A thylacocephalan. | |
| Concavicaris pikae | Sp. nov | Valid | Broda, Rak & Hegna | Devonian (Famennian) | | Poland | A thylacocephalan. | |
| Concavicaris submarinus | Sp. nov | | Jobbins, Haug & Klug | Devonian (Famennian) | | Morocco | A thylacocephalan. | |
| Concavicaris woodruffensis | Sp. nov | Valid | Broda, Rak & Hegna | Devonian (Famennian) | Woodruff Formation | United States | A thylacocephalan. | |
| Devonopilio | Gen. et sp. nov | Valid | Tihelka, Tian & Cai | Devonian (Pragian) | Rhynie chert | United Kingdom | Originally described as a member of Opiliones, but this interpretation was subsequently questioned by Pérez-González & Shultz (2021), who were unsure about the phylogenetic placement of this arthropod, but noted anatomical similarities with the euthycarcinoid species Heterocrania rhyniensis. The type species is D. hutchinsoni. | |
| Diplacanthocaris | Gen. et sp. nov | Valid | Ji et al. | Early Triassic | | China | A thylacocephalan. Genus includes new species D. chaohuensis. | |
| Dolesea | Gen. et sp. nov | Valid | Hannibal & May | Permian (Cisuralian) | Richards Spur locality | United States ( Oklahoma) | A millipede belonging to the group Helminthomorpha. The type species is D. subtila. | |
| Ericixerxes | Gen. et sp. nov | | Gueriau et al. | Devonian (Famennian) | Evieux | Belgium | A member of Euthycarcinoidea. The type species is E. potii. | |
| Hipponicharion perforata | Sp. nov | Valid | Skovsted et al. | Cambrian | Mural | Canada | A member of Bradoriida belonging to the family Hipponicharionidae. | |
| Itagnostus idahoensis | Sp. nov | Valid | Sundberg | Cambrian (Wuliuan) | Emigrant Formation Lakeview Limestone | United States | A member of Agnostida belonging to the family Peronopsidae. | |
| Kanoshoia | Gen. et sp. nov | Valid | Lerosey-Aubril et al. | Cambrian (Drumian) | Wheeler Shale | United States | A megacheiran. Genus includes new species K. rectifrons. | |
| Karstiulus | Gen. et sp. nov | Valid | Hannibal & May | Permian (Cisuralian) | Richards Spur locality | United States ( Oklahoma) | A millipede belonging to the group Juliformia, possibly a member of the superfamily Xyloiuloidea. The type species is K. fortsillensis. | |
| Keuperlimulus | Gen. et comb. nov | Valid | Lamsdell | Triassic | | France | A horseshoe crab. The type species is "Limulus" vicensis Bleicher (1897). | |
| Macrobelinurus | Gen. et comb. nov | Valid | Lamsdell | Carboniferous | | United Kingdom | A member of the family Belinuridae. The type species is "Steropis" arcuatus Baily (1859). | |
| Mesolimulus tafraoutensis | Sp. nov | In press | Lamsdell et al. | Late Cretaceous (Cenomanian–Turonian) | Gara Sbaa Lagerstätte | Morocco | A horseshoe crab. | |
| Microcaris rectilineatus | Sp. nov | Valid | Ji et al. | Early Triassic | | China | A thylacocephalan. Ehiro & Kano (2024) considered it to be a species belonging to the genus Parisicaris. | |
| Norilimulus | Gen. et comb. nov | Valid | Lamsdell | Carboniferous (Tournaisian) | Horton Bluff Formation | Canada | A member of Xiphosura belonging to the family Paleolimulidae. The type species is "Paleolimulus" woodae Lerner, Lucas & Mansky (2016). | |
| Oklahomasoma | Gen. et sp. nov | Valid | Hannibal & May | Permian (Cisuralian) | Richards Spur locality | United States ( Oklahoma) | A millipede belonging to the group Helminthomorpha. The type species is O. richardsspurense. | |
| Parabelinurus | Gen. et comb. nov | Valid | Lamsdell | Carboniferous | | Russia  Ukraine  United States | A member of the family Belinuridae. The type species is "Enthomolithus" lunatus Martin (1809); genus also includes P. iswariensis (Chernyshev, 1928), P. lacoei (Packard, 1885), P. metschetensis (Chernyshev, 1928) and P. stepanovi (Chernyshev, 1928). | |
| Paraconcavicaris | Gen. et comb. nov | Valid | Broda, Rak & Hegna | Carboniferous (Tournaisian) | Líšeň Formation | Czech Republic | A thylacocephalan; a new genus for "Concavicaris" viktoryni Rak, Broda & Kumpan (2018). | |
| Parioscorpio | Gen. et sp. nov | | Wendruff et al. | Silurian (Telychian) | Brandon Bridge | United States | An arthropod of uncertain phylogenetic placement. Originally classified as an early scorpion, but subsequently argued to be basal to crown group Mandibulata and Chelicerata. The type species is P. venator. | |
| Patesia | Gen. et comb. nov | Valid | Bicknell & Smith | Late Devonian | | United States | A stem xiphosurid; a new genus for "Kasibelinurus" randalli. Announced in 2020; the final version of the article naming it was published in 2021. | |
| Pauropsxenus extraneus | Sp. nov | In press | Su, Cai & Huang | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A millipede belonging to the family Polyxenidae. | |
| Pauropsxenus ordinatus | Sp. nov | In press | Su, Cai & Huang | Late Cretaceous (Cenomanian) | Burmese amber | Myanmar | A millipede belonging to the family Polyxenidae. | |
| Pruemopterus | Gen. et sp. nov | Valid | Poschmann | Early Devonian | | Germany | A eurypterid. Genus includes new species P. salgadoi. Announced in 2020; the final version of the article naming it was published in 2021. | |
| Pseudobeyrichona taurata | Sp. nov | Valid | Skovsted et al. | Cambrian | Mural | Canada | A member of Bradoriida belonging to the family Hipponicharionidae. | |
| Shpineviolimulus | Gen. et comb. nov | | Bicknell, Naugolnykh & Brougham | Permian (Asselian) | Araukaritovaya Formation | Ukraine | A member of Xiphosura belonging to the group Limulina; a new genus for "Paleolimulus" jakovlevi Glushenko & Ivanov (1961). | |
| Sklerolibyon | Gen. et sp. nov | | Aria et al. | Cambrian Stage 3 | Maotianshan Shale Member of the Yu'anshan Formation | China | A megacheiran related to Jianfengia and Fortiforceps. The type species is S. maomima. | |
| Soligorskopterus shpinevi | Sp. nov | Valid | Naugolnykh & Areshin | Late Devonian | | Russia | An eurypterid. Announced in 2019; the final version of the article naming it was published in 2020. | |
| Tariccoia tazagurtensis | Sp. nov | Valid | Pérez-Peris et al. | Early Ordovician | Fezouata | Morocco | A nektaspid arthropod. Announced in 2020; the final version of the article naming it was published in 2021. | |
| Thelxiope holmani | Sp. nov | Valid | Lerosey-Aubril, Skabelund & Ortega-Hernández | Cambrian (Drumian) | Wheeler Shale | United States | A possible member of Chelicerata. | |
| Volanalimulus | Gen. et sp. nov | Valid | Lamsdell | Early Triassic | Ankitokazo Basin | Madagascar | A horseshoe crab. The type species is V. madagascarensis. | |
| Xiaocaris | Gen. et sp. nov | | Liu et al. | Cambrian Stage 3 | Chiungchussu Formation | China | A member of the group Fuxianhuiida. The type species is X. luoi. | |
| Xiazhuangocaris | Gen. et sp. nov | Valid | Zeng et al. | Cambrian Stage 3 | Hongjingshao Formation | China | A member of Hymenocarina. Genus includes new species X. chenggongensis. Announced in 2020; the final version of the article naming it was published in 2021. | |

### General research

* Exceptionally preserved specimens of Chuandianella ovata carrying a large number of small eggs are described from the Cambrian Chengjiang biota (China) by Ou et al. (2020), who compare the reproductive strategies of C. ovata and closely related Waptia fieldensis.
* Sun, Zeng & Zhao (2020) report the discovery of a member of the genus Sidneyia belonging or related to the species S. inexpectans from the Wuliuan Mantou Formation of North China, expanding known distribution of this genus.
* A putative xiphosuran Kiaeria is reinterpreted as a member of Chasmataspidida by Lamsdell (2020a).
* A study on the anatomy of head structures of Heterocrania rhyniensis, evaluating its implications for the knowledge of the phylogenetic relationships of euthycarcinoids, is published by Edgecombe et al. (2020).
* A study on heterochrony in Xiphosura, showing that clades that occupy non-marine environments show elevated rates of peramorphosis or paedomorphosis is published by Lamsdell (2020b).
* A study on the morphology of the feeding apparatuses of Eurypterida and Trigonotarbida is published by Haug (2020).
* A study aiming to determine the range of prey sizes that could be captured by sweep-feeding eurypterids is published by Hughes & Lamsdell (2020).
* A study on the anatomy and phylogenetic relationships of Anhelkocephalon handlirschi is published by Schädel & Haug (2020), who interpret this taxon as a probable member of Cyclida rather than an isopod.
* Liu et al. (2020) report evidence of the presence of a three-dimensionally preserved labrum associated with the mouth opening in juvenile specimens of Leanchoilia illecebrosa.