$re = '/\(+[A-Za-z,_]+\)/m';
$str = '(((((((((((((((((((((((((((Cb_agil,M_leuco),(C_chrys,C_torqu)),M_sphin),Papi_Pa),Cer_lho),(P_hamad,(L_albig,(Tupa_ge,(P_anubi,L_aterr))))),M_sylva),Maca_ma),(M_thibe,(M_arcto,(M_siber,((((M_fusca,M_cyclo),M_fasci),M_mulat),(M_silen,(M_nemes,(M_orchr,(M_tonke,Maca_ni))))))))),((((C_aethi,C_sabae),(C_cynos,Erythro)),A_nigro),((((((Tupa_ob,Tupa_ph),Tupa_ha),(Tupa_de,Tupa_fr)),Tupa_ve),Tupa_au),(M_ogoue,((((C_negle,C_hamly),C_albog),C_diana),((C_wolfi,Cercop_),(C_petau,(Cercopi,(C_ascan,Cerc_ce))))))))),(Cb_ango,PilioCb)),(Cb_guer,(Presb_c,(P_melal,((((Semno_h,S_entel),S_entll),Nasalis),(P_nigri,(P_ciner,(P_nemae,Rhinopi)))))))),(Noma_ga,(((Noma_le,Noma_si),Noma_co),(((hylo_ag,hyloba_),hylo_mu),(Symphal,(png_pyg,(png_abe,((Homo_sa,Gorilla),(Pan_pan,(Ptroglo,P_trogl)))))))))),Galeopt),Tupa_ba),Cb_poly),((((((((A_hybri,A_fusci),A_geoff),(B_hypox,Lagot_c)),A_belze),(Atel_ch,B_arach)),A_panis),(L_lagot,Alutbel)),(Tupa_sy,(((((((C_melan,C_satan),P_irror),Cacaj_c),C_israe),C_coimb),(C_perso,C_nigri)),(Pitheci,(((((C_brunn,C_cupre),C_calig),C_donac),Callic_),(((Alouat_,Alout_S),A_palli),(S_boliv,(Saim_us,(S_sciur,(S_oerst,((((S_geoff,S_imper),S_labia),S_oedip),(S_mysta,(((S_marti,S_midas),S_fusci),(S_bicol,((Mico_hu,C_goeld),(((((Ca_geof,Ca_kuhl),Ca_peni),(Ca_jacc,Cebuell)),Ca_auri),(Mico_ar,(L_chrys,(L_rosal,((A_Linus,A_trivi),(C_xanth,(Cebs_ap,(C_robus,((C_capuc,C_oliva),(C_albif,(AaBoliv,(A_nancy,(AaInful,Aot_aza))))))))))))))))))))))))))))),Tupa_gl),Cynocep),Tupa_mi),rabbitr),(ArctoC_,(N_pygma,L_tardi))),Perodic),((((N_benga,N_couca),G_seneg),Daubent),(P_ver_c,((P_verre,P_tatte),(P_edwar,((P_diade,Avahi_l),(((E_rubri,Vv_rubr),E_coron),(((((((((Eul_mac,EuMac_f),Eulem_r),E_colla),E_sanfo),(Eul_ful,E_albif)),Eul_Mon),H_grise),Vv_vari),((H_occid,L_catta),(Lepi_ja,(L_ankar,(L_rufic,((L_septe,L_dorsa),(Micbus2,(Micbus1,(Mirza_z,Chei_me)))))))))))))))),O_crass),G_Galag),O_garne,G_thoma);
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php