The family Onychiuridae (Collembola) from karst caves of the Basque biospeleologic district, with description of four new species Author Beruete, Enrique 0000-0002-3240-8946 University of Navarra, Faculty of Sciences, Department of Environmental Biology, University Campus, 31080 Pamplona, Spain. eberuete @ yahoo. es; https: // orcid. org / 0000 - 0002 - 3240 - 8946 eberuete@yahoo.es Author Arbea, Javier I. c / Ría de Solía 3, ch. 39. 39610 El Astillero (Cantabria). Author Baquero, Enrique 0000-0002-3240-8946 University of Navarra, Faculty of Sciences, Department of Environmental Biology, University Campus, 31080 Pamplona, Spain. eberuete @ yahoo. es; https: // orcid. org / 0000 - 0002 - 3240 - 8946 & University of Navarra, Institute of Biodiversity and Environment (BIOMA), University Campus, 31080, Pamplona, Spain * corresponding author: ebaquero @ unav. es; https: // orcid. org / 0000 - 0002 - 2145 - 8606 eberuete@yahoo.es Author Jordana, Rafael 0000-0002-3240-8946 University of Navarra, Faculty of Sciences, Department of Environmental Biology, University Campus, 31080 Pamplona, Spain. eberuete @ yahoo. es; https: // orcid. org / 0000 - 0002 - 3240 - 8946 eberuete@yahoo.es text Zootaxa 2021 2021-09-21 5040 2 151 194 journal article 10.11646/zootaxa.5040.2.1 1175-5326 5531192 CC1289B1-4FF9-4369-A596-9FF260C8F314 Family ONYCHIURIDAE Börner, 1901 Key to the genera of Onychiuridae of the Basque bio-speleological district 1. Posterior cephalic pso absent. Furca reduced to two knobs with chaetae. Body fusiform.................... Kalaphorura - Posterior cephalic pso present. Furca reduced to a tegumentary fold or a finely granulated area with posterior microchaetae. Body oval-elliptical................................................................................... 2 2. Cephalic chaeta d 0 absent. PAO with simple vesicles. Furca reduced to a tegumentary fold with 2 + 2 microchaetae................................................................................................. Protaphorura - Cephalic chaeta d 0 present. PAO with composed vesicles. Furca reduced to a finely granulated area with 2 + 2 posterior microchaetae............................................................................................. 3 3. Abd III sternite divided into two subsegments, each with chaetae................................... Spinonychiurus - Abd III sternite not divided............................................................................. 4 4. Tibiotarsus with 11 chaetae on distal verticil................................................... Deharvengiurus - Tibiotarsus with 9 chaetae on distal verticil................................................................ 5 5. AbdV with 5−6 paired pso arranged in three rows............................................... Micronychiurus - AbdV with a fewer number of pso, arranged posteriorly in one row............................................. 6 6. With anal spines............................................................................. Onychiurus - Without anal spines................................................................................... 7 7. AIIIO with 5 papillae and curved guard sensilla................................................ Deuteraphorura - AIIIO with 4 papillae and straight guard sensilla................................................ Orthonychiurus