Jacekaphorura gen. nov. –– a new genus of Protaphorurini (Collembola: Onychiuridae) from mountainous Yakutia, East Siberia Author Pomorski, Romuald J. Author Babenko, Anatoly text Zootaxa 2010 2444 65 68 journal article 10.5281/zenodo.195023 408b597a-5f9a-4d47-85de-f3c57704071d 1175-5326 195023 Jacekaphorura gen. nov. Type species: Jacekaphorura sakhaensis sp. nov. Diagnosis . Body white, cylindrical with slightly broadened tip, Abd .6 small, hardly separated from Abd .5, anal spines absent. Integument with fine and regular granulation. Pseudocelli present on both dorsal and ventral sides of body, Th .1 with dorsal pso . Furca remnant as finely granulated area with 2+2 posterior setae, arranged in two rows in middle part of abdominal sternum 4. AO with 5 papillae and granulated sensory clubs. Postantennal organ with simple vesicles. Labial palp of A-type ( Fjellberg 1999 ). Maxillary head with unmodified lamellae. Dorsal chaetotaxy plurichaetotic, both micro- and macrosetae pointed. Th .2–3 with lateral microsensilla. Unpaired dorsal seta d 0 on head absent. Thoracal sterna and VT base without setae. Tibiotarsi with 11 setae in distal whorl. Etymology. The genus named by Anatoly Babenko after Romuald Jacek Pomorski whose prominent activity in Onychiuridae studies was suddenly severed by his untimely decease. Discussion . Jacekaphorura gen. nov. is characterized by simple vesicles in PA O , the absence of d 0 on head, and a complete distal row of setae on tibiotarsi which points to its probable position within Protaphorurini. The most notable features of the new genus distinguishing it from other members of the tribe are furca vestige without clear cuticular structures and the complete absence of anal spines. In the tribe it shares the former character only with Megaphorura Fjellberg, 1998 , which however differs by having strong anal spines and setae on all thoracal sterna and VT base. Apart from these characters, a triangular position of anterior pso on head, as well as the separation of the most lateral pso on Abd . 5 are also untypical of the tribe. There are a few characters that are common for Jacekaphorura gen. nov. and Thalassaphorurini, mainly furca vestige and mutual position of some pso . However, most of Thalassaphorurini are characterized by the presence of d 0 on head, reduced number of distal tibiotarsal setae (all or some T -setae are absent), and marked antennal and dorsal sensilla. Using the interactive key of Onychiurinae ( Bellinger et al. 1996 – 2010 ) the genus appears close to Similonychiurus Pomorski, 2007 and Spelaphorura Bagnall, 1948 . The former is a Nearctic genus belonging to a different subfamily, Lophognatellinae (probably mistakenly placed in the key), characterized by strongly modified mouth parts (maxillae and labial palp). Apart from this character, Jacekaphorura and Similonychiurus can be distinguished by different structure of furca remnant with 2+2 small posterior setae in two rows in the former versus a convexity with 1+1 setae in the latter, number of papillae, guard setae and shape of sensory clubs in AO (5 papillae, 5 setae, clubs granulated in Jacekaphorura versus 4 papillae, 4 setae and stick-like clubs in Similonychiurus ), as well as by differentiated tergal sensilla, unique elevated mushroom-like shape of pso , and the absence of psx in Similonychiurus . FIGURES 1–7. Jacekaphorura sakhaensis sp. nov. (holotype, mature female): 1, tip of Ant .4; 2, AO ; 3, sensilla of AO ; 4, PA O ; 5, labial palp; 6, dorsal chaetotaxy and pso localization; 7, distal part of fore leg. Scale bars: 1–4––0.01 mm, 5, 7––0.05 mm, 6––0.1 mm. The diagnosis of the second similar genus, Spelaphorura from Himalaya caves is unfortunately incomplete and at present the genus can not be attributed to any existing tribe of Onychiurinae . Nevertheless the unique structure of sensory clubs in AO , split into few long lobes as figured by Salmon (1959) , clearly distinguishes it from the Jacekaphorura gen.n. having granulated clubs in AO .