Platyseius Berlese

De Moraes, Gilberto J., Britto, Erika P. J., Mineiro, Jefferson L. De C. & Halliday, Bruce, 2016, Catalogue of the mite families Ascidae Voigts & Oudemans, Blattisociidae Garman and Melicharidae Hirschmann (Acari: Mesostigmata), Zootaxa 4112 (1), pp. 1-299 : 44-45

Platyseius Berlese

FEMALE

Gnathosoma. Anterior margin of epistome with three anterior projections, the median projection much longer than others in P. horridus (Evans & Hyatt) , usually slightly enlarged and denticulate distally, or acuminate and smooth. Seta h1 markedly longer than h2, h3 and pc; insertion of h2 slightly posterior to insertion of h3. Inner palp trochanter seta elongate. Deutosternum without delimiting lateral lines and with seven rows of multiple denticles; distance between fifth and sixth rows more than 1.5 times distance between fourth and fifth (only 1.3 times in P. horridus ). Corniculi 1.5–2.5 as long as their basal widths, well separated from each other, subparallel. Cheliceral digits of similar lengths, elongate; fixed digit with 8–20 fine teeth usually on an elevated ridge (edentate in P. berlesei (Krantz) and P. triangralis Ishikawa), and large subapical tooth; with a deep subapical notch to receive apex of movable digit; movable digit with two teeth in addition to apical tooth (edentate in P. berlesei ).

Idiosoma. Idiosoma oval to subcircular. Dorsum: dorsal shield smooth or ornamented, without lateral incisions at region of fusion or delineated strip along lateral margins; anterior end of dorsal shield not strongly deflexed. No supernumerary setae on dorsal shield. Podonotal region of shield with 19–21 pairs of setae, including r3, which is similar to neighbouring setae. Opisthonotal region of shield with 12–15 pairs of setae (missing 1–3 pairs of J setae). Unsclerotised lateral cuticle with 0–7 pairs of setae. Dorsal and lateral setae of idiosoma short or long, acicular or undulating distally, smooth. Ve n t e r: without presternal platelets or with a pair of entire or transversely fragmented platelets. Sternal shield with three pairs of setae (st1–st3); st2 and st3 of similar lengths, usually much longer than st1, which is about as long as st4; st2 either about equidistant to st1 and st3 or distinctly closer to st3; posterior shield margin concave. Third pair of lyrifissures (iv3) and st4 inserted on metasternal plates. Genital shield not wide enough to include iv5, but including st5; posteriorly truncate to slightly convex. None or one pair of metapodal plates, which may be fused with peritrematic shield. Usually with 1–3 pairs of platelets between genital and ventrianal shield (in some species, with a sclerotised line in addition to or instead of platelets). Opisthogaster with 5–8 pairs of setae in addition to circumanal setae, of which 3–7 pairs on subtriangular to ellipsoidal ventrianal shield (some may be posterior to anal opening); seta Zv1 absent (present in P. horridus ); para-anal setae inserted posteriad of level of mid-length of anal opening, often well behind posterior margin of anal opening, shorter to longer than post-anal seta. Anal opening small, 1/5 to 1/9 of shield length, usually separated from posterior shield margin. Ventrianal shield free or fused posteriorly with dorsal shield. Anterior section of endopodal shield fused with sternal shield (small remnant between coxae II–III in P. triangralis ); section behind sternal shield usually reduced to very distinct V- to T-shaped platelet between coxae III–IV (sometimes fragmented) that in some species almost meet exopodal shield behind coxa IV. Exopodal shield usually distinct (may be reduced respectively to two and one triangular fragments between coxae I–II and II–III in P. estrellae Lindquist ).

Peritreme. Usually extending forward from stigma to fuse with peritreme of the opposite side; very wide and with a variable number of constrictions along dorsal margin in some species; usually with post-stigmatic extension of variable length, surpassing posterior margin of coxa IV. Peritrematic shield wide, broadly fused with dorsal shield at level of s1 and with exopodal shield beside coxa IV.

Legs. Median section of pulvilli of legs II–IV acute; paradactyli of these legs elongate and acuminate. Setation of legs I–IV, genu: 13, 10, 8, 9; tibia: 13, 9, 9 (or 8), 10 (in P. horridus , genu: 12, 10, 8, 8; tibia: 12, 10, 8, 9). Leg II not distinctly different from other legs. Tarsus I with an erect seta; setae ad1 and pd1 greatly elongate, about twice as long as paradactyli (not elongate in P. horridus ); usually with two elongate and partially flattened setae on tarsi II– III and one on tarsus IV.

Spermathecal apparatus. Phytoseiid-type.

MALE

Gnathosoma similar to female, but fixed digit with 6–12 small teeth between setiform pilus dentilis and subapical notch, not on elevated ridge as in female, and movable digit with one tooth in addition to apical tooth; spermatodactyl 2–4 times as long a movable digit, slightly tapered distally, directly basally forward and then usually curving backwards medially or distally (almost straight in P. cooki Lindquist and P. major (Halbert)) or spiral-shaped. Dorsal shield with ornamentation similar to female, but usually broader, including a larger number of r - R setae ; (with one less seta on podonotal region of dorsal shield in P. italicus (Berlese)) . With 1–3 pairs of presternal platelets. Sternogenital shield with four pairs of setae (st1–st3 and st5) and three pairs of lyrifissures (iv1–iv3), not fused with ventrianal or peritrematic shields; slightly concave posteriorly; st1 usually distinctly shorter than other sternal setae; st2–st3 the longest. Endopodal shield usually totally fused with sternogenital shield. Metapodal plates absent. Opisthogaster with 5–6 pairs of setae in addition to circumanal setae, all on broad ventrianal shield that covers almost the whole opisthogaster, which abuts sternogenital shield; fused or not to dorsal shield. Peritrematic shield fused with exopodal shield beside coxa IV, abutting or fused with ventrianal shield. Setation and other leg structures similar to female.