In 2025, several new arthropod fossil taxa, including arachnids, crustaceans, trilobites, and other arthropods (for insects, see 2025 in paleoentomology) were announced or described. Other significant arthropod paleontological discoveries and events also occurred in 2025.
Chelicerates Arachnids Amblypygi NameNoveltyStatusAuthorsAgeType localityLocationNotesImagePhrynus luisdearmasiSp. novValidDunlop & BartelMiocene (probably Burdigalian)Dominican amberA species of Phrynus.Phrynus poinariNom. novValidDunlop & BartelMioceneMexican amberA species of Phrynus; a replacement name for Phrynus mexicana Poinar & Brown (2004).
Araneae NameNoveltyStatusAuthorsAgeType localityLocationNotesImageBalticonesticus rectusSp. novValidWunderlichEoceneBaltic amberEurope (Baltic Sea region)A scaffold web spider.BaltplanarchaeaGen. et comb. novValidWunderlichEoceneBaltic amberEurope (Baltic Sea region)A spider belonging to the family Planarchaeidae. The type species is "Planarchaea" oblonga Wunderlich (2017).Burmesarchaea spinicaputSp. novValidWunderlichCretaceousKachin amberA spider belonging to the family Archaeidae.Cornuanandrus scutatusSp. novValidWunderlichEoceneBaltic amberEurope (Baltic Sea region)A spider belonging to the family Synotaxidae.FurczarqaGen. et sp. novValidWunderlichCretaceousKachin amberA spider belonging to the family Zarqaraneidae. The type species is F. incerta.FushunpalpimanusGen. et sp. novValidWunderlichEoceneFushun amberA spider belonging to the family Palpimanidae. The type species is F. exuviae.Heteronesticus acuminatusSp. novValidWunderlichEoceneBaltic amberEurope (Baltic Sea region)A scaffold web spider.Heteronesticus bitterfeldensisSp. novValidWunderlichEoceneBitterfeld amberA scaffold web spider.LongthoraxNom. novValidWunderlichCretaceousKachin amberA spider belonging to the family Tetrablemmidae; a replacement name for Longithorax Wunderlich (2017).MicrolininusNom. novValidWunderlichEoceneBaltic amberEurope (Baltic Sea region)A replacement name for Microlinus Wunderlich (2004).?Mimetus flexuosusSp. novValidWunderlichEoceneBaltic amberEurope (Baltic Sea region)A possible species of Mimetus.ParvispininaNom. novValidWunderlichCretaceousKachin amberA spider belonging to the family Zarqaraneidae; a replacement name for Parvispina Wunderlich (2015).PectenzodarionGen. et sp. novValidWunderlichEoceneBaltic amberEurope (Baltic Sea region)An ant spider. The type species is P. unicum.Planarchaea humilisSp. novValidWunderlichCretaceousKachin amberA spider belonging to the family Planarchaeidae.Planarchaea longipalpitibiaSp. novValidWunderlichCretaceousKachin amberA spider belonging to the family Planarchaeidae.Planarchaea petersiSp. novValidWunderlichCretaceousKachin amberA spider belonging to the family Planarchaeidae.Planarchaea quinquespinaeSp. novValidWunderlichCretaceousKachin amberA spider belonging to the family Planarchaeidae.Succinitaxus pusillusSp. novValidWunderlichEoceneBaltic amberEurope (Baltic Sea region)A spider belonging to the family Synotaxidae.Succinitaxus strepitusSp. novValidWunderlichEoceneBaltic amber Bitterfeld amberBaltic Sea regionA spider belonging to the family Synotaxidae.
Spider research A female spider belonging to the genus Parvosegestria interpreted as preserved guarding her clutch of eggs and offspring partly free from their cover is described of a piece of Cretaceous Kachin amber by Wunderlich (2025). Córdova-Tabares, Estrada-Ruiz & Riquelme (2025) report the first discovery of a ray spider specimen in the Mexican amber.
Ixodida NameNoveltyStatusAuthorsAgeType localityLocationNotesImageAmblyomma arawakanSp. novValidChitimia-Dobler & Martins in Milde et al.MioceneDominican amberA hard tick, a species of Amblyomma.
Pseudoscorpiones NameNoveltyStatusAuthorsAgeType localityLocationNotesImageEchinocheliferGen. et sp. novFeng et al.CretaceousKachin amberA member of the family Cheliferidae. The type species is E. curvatus.Lechytia finniaeSp. novHagen et al.Late Cretaceous (Cenomanian)Kachin amberA species of Lechytia.PalaeochiridiumGen. et sp. novValidTurbanov et al.CretaceousA member of the family Pseudochiridiidae. The type species is P. insolitum.
Sarcoptiformes NameNoveltyStatusAuthorsAgeType localityLocationNotesImageAzarliodesGen. et comb. novArillo & GutiérrezEarly CretaceousLebanese amberA mite belonging to the family Neoliodidae; a new genus for "Neoliodes" andreneli Arillo et al. (2019).Histiogaster altilisSp. novValidKolesnikov et al.EoceneRovno amberA species of Histiogaster.Paralycus ekaterinaeSp. novValidKolesnikov et al.Eocene (Priabonian)Rovno amberA member of Oribatida belonging to the family Pediculochelidae.Paralycus primusSp. novValidKolesnikov et al.Late Cretaceous (Cenomanian)Kachin amberA member of Oribatida belonging to the family Pediculochelidae.PlesioglyphusGen. et sp. novValidSendi et al.Early Cretaceous (Barremian)Lebanese amberA member of the family Schizoglyphidae. The type species is P. lebanotermi.
Sarcoptiform research Klimov et al. (2025) revise Protospeleorchestes pseudoprotacarus, Paraprotacarus hirsti and Palaeotydeus devonicus from the Devonian Rhynie chert (United Kingdom) and interpret them all as junior synonyms of Protacarus crani, assigned by the authors to the new family Protoacaridae within Endeostigmata; the authors also study the diversification timeline of acariform mites, and argue that the crown group of Acariformes originated during the Cambrian, at the time of colonization of lands by bryophytes.
Scorpiones NameNoveltyStatusAuthorsAgeType localityLocationNotesImageArchaeoananteroides carusoiSp. novValidLourenço in Lourenço & VeltenCretaceousKachin amberA scorpion belonging to the superfamily Buthoidea and the family Ananteridae.Betaburmesebuthus groehniSp. novValidLourenço in Lourenço & VeltenCretaceousProbably Kachin amberA scorpion belonging to the superfamily Buthoidea and the family Palaeoburmesebuthidae.Betaburmesebuthus petersiSp. novValidLourenço in Lourenço & VeltenCretaceousProbably Kachin amberA scorpion belonging to the superfamily Buthoidea and the family Palaeoburmesebuthidae.Burmesescorpiops wunpawngSp. novValidLourenço, Dan & ZawgyiCretaceousKachin amberA scorpion belonging to the family Palaeoeuscorpiidae.Cretaceoushormiops petersiSp. novValidLourenço in Lourenço & VeltenCretaceousKachin amberA scorpion belonging to the family Protoischnuridae.JeholiaGen. et sp. novValidXuan et al.Early CretaceousYixian FormationA member of Buthida of uncertain affinities. The type species is J. longchengi.Palaeoburmesebuthus sarahmeyeraeSp. novValidLourenço in Lourenço & VeltenCretaceousKachin amberA scorpion belonging to the superfamily Buthoidea and the family Palaeoburmesebuthidae.PalaeobutheolusGen. et 2 sp. novValidLourenço in Lourenço & VeltenCretaceousKachin amberA scorpion, possibly a member of the family Buthidae. The type species is P. andreschmidti; genus also includes P. staxi.ParatrilineatusGen. et sp. novValidLourenço in Lourenço & VeltenCretaceousKachin amberA scorpion belonging to the superfamily Buthoidea and the family Palaeotrilineatidae. The type species is P. schmidti.Serratochaerilobuthus barbaraeSp. novValidLourenço & VeltenCretaceousKachin amber
Scorpion research Callaghan & Boyce (2025) argue that a footless posture does not provide strong support for an aquatic habitat in fossil scorpions by itself, interpret the fossil evidence as overall supporting terrestrial origin of total group of Scorpiones. Xuan et al. (2025) revise scorpions from the family Chaerilobuthidae known from the Cretaceous Kachin amber from Myanmar, reinterpret Chaeriloiurus and Serratochaerilobuthus as junior synonyms of the genus Chaerilobuthus, and rerank the family Chaerilobuthidae itself as a subfamily belonging to the family Pseudochactidae.
Trombidiformes NameNoveltyStatusAuthorsAgeType localityCountryNotesImagesCaeculus aeternusSp. novPorta et al.EoceneBaltic amberEurope (Baltic Sea region)A member of the family Caeculidae.CretachyzeriaGen. et sp. novValidLiu, Fan & RenLate Cretaceous (Cenomanian)Kachin amberA member of the family Chyzeriidae. The type species is C. macroseta.PunkochyzeriaGen. et 3 sp. novValidKolesnikov, Turbanov & VorontsovCretaceousKachin amberA member of the family Chyzeriidae. Genus includes new species P. minaevi, P. makolae and P. khoyi.ScleroerythraeusGen. et sp. novCosta et al.EoceneBaltic amber()An erythraeid mite. Genus includes new species S. ferox.
Trombidiform research New caeculid specimens, including the first fossil caeculid larva, are described from the Cretaceous Kachin amber from Myanmar by Gerbe et al. (2025).
Uropygi NameNoveltyStatusAuthorsAgeType localityCountryNotesImagesMesothelyphonus xiaoaeSp. novWu et al.CretaceousKachin amberA whip scorpion.
Other arachnids
Other arachnid research Santos et al. (2025) describe fossil material of Gzhelian trigonotarbids: Aphantomartus sp. from the Bierzo Coalfield and Aphantomartus areolatus from the Villablino Coalfield (Spain), associated with plant remains indicating that the studied arachnids likely lived in humid evergreen forests.
Eurypterids NameNoveltyStatusAuthorsAgeType localityCountryNotesImagesAthenepterusGen. et comb. novValidLamsdellSilurian (Přídolí)A member of the family Hardieopteridae. The type species is "Eurypterus" megalops Salter (1859); genus also includes A. sigmoidalis (Kjellesvig-Waering, 1971).BarusopterusGen. et comb. novValidLamsdellSilurian (Ludlow)()A member of Dolichopteroidea belonging to the family Strobilopteridae. The type species is "Onychopterus" limuloides Kjellesvig-Waering (1948).?Carcinosoma auroraeSp. novValidVan Roy, Richards & Ortega-HernándezOrdovician (Tremadocian)Fezouata FormationCruinnopterusGen. et comb. novValidLamsdellSilurian (Llandovery–Wenlock)()A member of the family Carcinosomatidae. The type species is "Eurypterus" scorpioides Woodward (1868); genus also includes C. scotica (Laurie, 1899).HunanopterusFam. et gen. et comb. novValidLamsdellSilurian (Llandovery–Přídolí)A member of the superfamily Pterygotoidea, the type genus of the new family Hunanopteridae. The type species is "Hughmilleria" wangi Tetlie, Selden & Ren (2007).SelkiepterellaGen. et comb. novValidLamsdellSilurian (Llandovery–Přídolí)A member of the family Adelophthalmidae. The type species is "Himantopterus" lanceolata Salter (1856); genus also includes S. cephalaspis (Salter in Sedgwick and McCoy, 1855).TigrisopterusGen. et sp. novWang, Sun & ZhangDevonian (Lochkovian)Nagaoling FormationA member of the family Carcinosomatidae. The type species is T. zengi.WaterstonopterusGen. et comb. novValidLamsdellSilurian (Llandovery–Wenlock)()A member of the family Hardieopteridae. The type species is "Hardieopterus" lanarkensis Waterston (1979); genus also includes W. myops (Clarke, 1907).
Eurypterid research Wang et al. (2025) revise Devonian pterygotid eurypterids from the Xiaxishancun Formation (Yunnan, China) and introduce a new nomenclature to define the cheliceral denticles of pterygotids.
Xiphosurans NameNoveltyStatusAuthorsAgeType localityCountryNotesImagesCiurcalimulusGen. et sp. novValidLamsdellSilurian (Ludlow)Wabash Formation()The type species is C. discobolus.Lunataspis gundersoniSp. novLamsdell et al.Ordovician (Katian)Big Hill Formation()Bears an unusually elongated shovel-shaped prosoma with recurved spines.
Xiphosuran research Evidence indicating that fusion of the opisthosomal segments happened once in the common ancestor to Xiphosura, while loss of visible segment boundaries happened several times during the xiphosuran evolution, is presented by Lamsdell & Ocon (2025).