The Mesozoic stage in the evolution of the family Nemonychidae is studied. The phylogeny and morphology of this family are considered; 80 species of 42 genera are recorded in the Mesozoic fauna. The group is reviewed. Diagnoses and descriptions are made. Keys to taxa are given. New genera, Cratonemonyx Legalov, gen. nov. (with the type species Cratonemonyx martinsnetoi Legalov, sp. nov.), and Baissimberis Gratshev et Legalov, gen. nov. (with the type species Baissimberis prodigiosus Gratshev et Legalov, sp. nov.), the new species Oxycorynoides (Pseudoxycorynoides) sukatshevae Legalov, sp. nov. (Karatau locality), Ampliceps zimmermanni Legalov, sp. nov. (Karatau locality), Archaeorrhynchus carpenteri Legalov, sp. nov. (Karatau locality), Probelus (Probelus) handlirschi Legalov, sp. nov. (Karatau locality), P. (P.) nikolaevi Legalov, sp. nov. (Karatau locality), P. (P.) scudderi Legalov, sp. nov. (Karatau locality), Belonotaris (Arnoldibelus) heeri Legalov, sp. nov. (Karatau locality), B. (A.) rohdendorfi Legalov, sp. nov. (Karatau locality), B. (A.) rasnitsyni Legalov, sp. nov. (Karatau locality), Distenorrhinus (Distenorrhinus) ovatus Gratshev et Legalov, sp. nov. (Khasurtyi locality), Cratonemonyx martinsnetoi Legalov, sp. nov. (Santana locality), Baissimberis prodigiosus Gratshev et Legalov, sp. nov. (Baissa locality), and Chinocimberis dispersus Gratshev et Legalov, sp. nov. (Khutel-Kharalocality) are described. Belonotaroides Legalov, 2009, syn. nov. for Oxycorynoides L. Arnoldi, 1977, Scelocamptus L. Arnoldi, 1977, syn. nov., Karataucar Legalov, 2009, syn. nov., Gratshevicar Legalov, 2009, syn. nov. and Medmetrioxenoides Gratshev et Legalov, 2009, syn. nov. for Ampliceps L. Arnoldi, 1977, Eccoptarthroides Legalov, 2010, syn. nov. for Astenorrhinus Gratshev et Zherikhin, 1995, Oxycorynoides rohdendorfi L. Arnoldi, 1977, syn. nov. and Belonotaris lineatipunctatus L. Arnoldi, 1977, syn. nov. for Oxycorynoides similis L. Arnoldi, 1977, Oxycorynoides progressivus L. Arnoldi, 1977, syn. nov. for Ampliceps dentitibia L. Arnoldi, 1977, Oxycorynoides zherichini L. Arnoldi, 1977, syn. nov., O. ponomarenkoi L. Arnoldi, 1977, syn. nov., Paroxycorynoides elegans L. Arnoldi, 1977, syn. nov. and Medmetrioxenoides prodromus Gratshev et Legalov, 2009, syn. nov. for Ampliceps furcitibia L. Arnoldi, 1977, Scelocamptus curvipes L. Arnoldi, 1977, syn. nov. for Ampliceps tenuirostris (L. Arnoldi, 1977), Distenorrhinus arnoldii Gratshev et Zherikhin, 1995, syn. nov. for D. angulatus L. Arnoldi, 1977, Distenorrhinus rotundicollis Gratshev et Zherikhin, 1995, syn. nov. for D. pallidirostris Gratshev et Zherikhin, 1995, Pseudobrenthorrhinus crassicornis Gratshev et Zherikhin, 1996, syn. nov. for Eccoptarthrus crassipes L. Arnoldi, 1977, Eccoptarthroides nikitskyi Legalov, 2010, syn. nov. for Astenorrhinus martynovi (Legalov, 2010), Eccoptarthroides longirostris Legalov, 2010, syn. nov. for Astenorrhinus elongatus (Gratshev et Zherikhin, 1995), Eccoptarthroides ponomarenkoi Legalov, 2010, syn. nov. for Astenorrhinus major (Gratshev et Zherikhin, 1995), Eccoptothorax latipennis L. Arnoldi, 1977, syn. nov. for Procurculio fortipes L. Arnoldi, 1977, Probelopsis acutiapices L. Arnoldi, 1977, syn. nov. for Probelus longitarsus L. Arnoldi, 1977 are established. Changes of the status of Astenorrhinus Gratshev et Zherikhin, 1995, stat. nov. is ranked from subgenus to genus, and Arnoldibelus Legalov, 2009, stat. nov. is ranked from genus to subgenus. Ampliceps dubius (L. Arnoldi, 1977), comb. nov., A. tenuirostris (L. Arnoldi, 1977), comb. nov. , Belonotaris (Arnoldibelus) zherichini (Legalov, 2010), comb. nov., B. (A.) gratshevi (Legalov, 2010), comb. nov., Astenorrhinus martynovi (Legalov, 2010), comb. nov., A. elongatus (Gratshev et Zherikhin, 1995), comb. nov. and A. major (Gratshev et Zherikhin, 1995), comb. nov. are established.
