A new water mite genus from Kazakhstan (Acari, Hydrachnidia, Hydryphantidae) Author Tuzovskij, Petr V. 0000-0001-5002-2679 Papanin Institute for Biology of Inland Waters of the Russian Academy of Sciences, Borok, Yaroslavl Province, 152742, Russia. tpv @ ibiw. ru; https: // orcid. org / 0000 - 0001 - 5002 - 2679 tpv@ibiw.ru Author Stolbov, Vitaly A. Tyumen State University, Tyumen, 625003, Russia. text Zootaxa 2021 2021-04-01 4951 1 187 192 journal article 7401 10.11646/zootaxa.4951.1.11 4017a03d-0516-45cb-86f3-88f395927dfc 1175-5326 4655576 6ED8C2E8-2DAC-4188-A5E0-6B0222A2D2FE Eupanisellus n. gen. Type species. Eupanisellus kazakhstanicus sp. n. Diagnosis . Pre- and postfrontalia and first pair of dorsocentral platelets fused into large frontal plate bearing median eye and trichobithria Oi ; lateral eyes in capsules, eye lenses fused to each other on each side; fifth pair of dorsocentral plates larger than other dorsocentral platelets, all dorsolateral platelets and dc.2–dc.4 subequal in size, third pair of dorsocentral platelets (dc.3) medially fused in male and separated in female; anterior coxal groups with rounded medial margin and distinctly separated; all genital acetabula free, number of acetabula variable, two (occasionally three) acetabula anterior and four to seven acetabula posterior to the genital flaps on each side; two to four genital setae located on small sclerite anterior to genital flap, and one seta posterior to genital flap on each side; P-4 slender, with single dorsodistal peg-like seta; legs without swimming setae. Remarks . The new genus is similar to the genera Panisellus Viets, 1925 , Placothyas Lundblad, 1945 and Amerothyasella Smith & Cook, 1999 . All named genera especially well differ from Eupanisellus n. gen. by a structure of dorsum and arranged of genital setae: pre- and postfrontalia fused into an enlarged frontal plate, all dorsocentral plates (dc.1–dc. 5) free, genital setae located on flaps only; while in Eupanisellus n. gen. pre- and postfrontalia and first pair of dorsocentral plates (dc. 1) fused an elongate frontal plate, part of the genital setae located anterior and posterior of genital flaps. In additional, Eupanisellus n. gen. differs from the named genera also and other features. The new genus is similar to Panisellus in the structure of the genital field which is characterised by presence several acetabula located posterior to the genital flaps on each side, but differs in the following characters (character states of Panisellus given in parenthesis, data from Cook 1974 , Bader 1984, Di Sabatino et al 2010 ): lateral eyes in capsules, eye lenses fused to each other on each side (lying on common plates, eye lenses distinctly separated on each side), median eye present (absent), all dorsal and ventral platelets occupying less than one half of the idiosoma surface (most of the idiosoma surface), genital field and excretory pore distinctly separated (close to each other), P-4 long, with a single peg–like dorsodistal seta (P-4 short, with two stout peg-like distal setae). The genital field in a species of the genus Placothyas with four or five acetabula, a pair of anterior acetabula on each side located on common sclerite, no acetabula located posterior to genital flaps ( Cook 1974 , Bader 1984). The idiosoma in members of Amerothyasella with large plates occupying most of dorsal and postcoxal ventral surface, genital field with three pairs (males) or four pairs (females) of genital acetabula, posterior two or three pairs free (not fused with genital flaps); genital flaps not extending anterior to first pair of acetabula ( Smith and Cook 1999 ). Etymology . The generic name is derived from eu [eu comes from the Greek well, properly, good] and the genus name Panisellus .