Tropicoseius Baker & Yunk

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 : 56-58

Tropicoseius Baker & Yunk er

FEMALE

Gnathosoma. Anterior margin of epistome with a median pointed (sometimes subdivided distally for a very short distance) or convex projection, smooth. Ratio of lengths of hypostomatic and pc setae variable; usually either h3 longest and h2 shortest, or setae of similar lengths; insertion of h2 very close to insertion of h3, anterior or well anterior to it. Inner palp trochanter seta not elongate. Deutosternum moderately wide, with delimiting lateral lines and seven rows of 5–7 denticles each. Corniculi often difficult to distinguish, 1–3 times as long as their basal widths, with pointed tips, distally convergent; in some species so much so that apices cross each other distally in mounted specimens. Palp tarsal apotele two-tined. Cheliceral digits short; fixed digit with 1–3 teeth in addition to apical tooth and a distinct membranous lobe instead of setiform pilus dentilis; movable digit edentate and with a ventral mucro (apparently lacking in some species).

Idiosoma. Ovoid. Dorsum: podonotal and opisthonotal shields generally fused (separate in T. erioxynon Naskrecki & Colwell and T. fuentesi Naskrecki & Colwell ), usually well ornamented over entire shield or near margins, with distinct lateral incisions at region of fusion, with or without line connecting the incisions; incision also commonly present between insertions of S3 and S4; without delineated strip along lateral margins; anterior end of dorsal shield not strongly deflexed. No supernumerary setae on dorsal shield. Podosomal region of the shield usually with 17 pairs of setae (rarely 16 pairs, when j1 is inserted off the shield, 18 or 19 setae; z3 absent; s6 present). Opisthonotal region of shield with 15 pairs of setae (14 in T. erioxynon , because S1 absent; some specimens of T. heliconiae Baker & Yunker without Z5). Unsclerotised lateral cuticle with 9–22 pairs of setae (when supernumerary setae present, located near posterior opisthogastric setae), including r3, which is similar to neighbouring setae. Usually most dorsal idiosomal setae of similar lengths, short, acicular and smooth; in a few species, some dorsal shield setae minute or Z5 distinctly longer than other setae (and stout in T. berryi Naskrecki & Colwell ); lateral idiosomal setae usually similar to dorsal shield setae (in some species, distinctly longer and stouter). Ve n t e r: presternal platelets indistinct; with a pair of prominent lobes connected to anterior margin of sternal shield. Sternal shield with three pairs of setae of similar lengths (st1–st3; the original description of T. chlorestes (Fain, Hyland & Aitken) shows only two pairs of setae (st1–st2) on the shield; st2 equidistant to st1 and st3 or slightly closer to st3; posterior shield margin usually concave, sometimes slightly concave to truncate. Third pair of sternal lyrifissures (iv3) and st4 inserted on unsclerotised cuticle. Genital shield of some species broadened posteriorly, but not sufficiently to include iv5; st5 inserted on the margin of the shield; anterior hyaline region tapered or broadly rounded, never with median indentation; posterior region slightly to distinctly convex. A pair of elongate to triangular metapodal plates. Usually with no platelets between genital and anal shields; rarely 1–2 pairs of platelets. Opisthogaster usually with ten pairs of setae (rarely eight or nine pairs or 1–2 supernumerary setae between Jv1 and Jv2) on unsclerotised cuticle, in addition to circumanal setae; anal shield usually small and ovoid (round or subquadrate in some species; broad and subquadrate in T. colombiensis (Fain & Hyland)) ; para-anal setae inserted between levels of anterior margin and mid-length of anal opening, usually much shorter than post-anal seta, the latter often stout. Anal opening small, 1/5 to 1/9 of shield length, in shield centre or behind it, separated from posterior shield margin. Anterior section of endopodal shield fused with sternal shield; section behind sternal shield indistinct or reduced to elongate or V-shaped platelet beside coxae III–IV. Exopodal shield usually lightly sclerotised and difficult to distinguish; in some species conspicuous, extending along coxae II–IV, curving behind coxa IV.

Peritreme. Extending from stigma to level of z1; in some species shorter, but extending well beyond s1. Peritrematic shield relatively narrow, fused with dorsal shield at level of s1 and by narrow bridge to exopodal shield beside coxa IV.

Legs. Setation of legs I–IV, genu: 13, 11, 9, 9; tibia: 13, 10, 9, 10. Leg II not distinctly different from other legs or slightly stouter. Leg setae generally short.

Spermathecal apparatus. Usually seen as a long tube of varying diameter and without infundibulum (with rudimentary infundibulum in T. erioxynon ).

MALE

Epistome similar to female, but usually with central projection longer; fixed cheliceral digit with 1–2 teeth in addition to apical tooth (rarely edentate) and membranous lobe; movable digit edentate, shorter than fixed digit; spermatodactyl variously shaped, 2–5 times as long as movable digit, almost straight or variously bent, directed forward at least at the base. Dorsal shield usually with distinct lateral incisions between podonotal and opisthonotal regions, often connected by a transverse line; occasionally without incisions or podonotal and opisthonotal shields not fused; ornamentation similar to female, but usually broader, including a larger number of r - R setae ; in addition, within each species, dorsal idiosomal setae often of widely variable lengths, many often much longer than in female. Presternal platelets absent. Sternogenital shield with five pairs of setae (st1–st5; the latter off the shield in T. berryi and T. chazdonae Naskrecki & Colwell ) and three pairs of lyrifissures (iv1–iv3); not fused with ventrianal or peritrematic shields; posterior margin truncate or convex (undulating in T. peregrinator Baker & Yunker ). Endopodal shield totally fused with sternogenital shield anteriorly to coxa IV; section of endopodal shield beside coxa IV fused with sternal shield by anterior end, or atrophied, so that sternogenital shield with a pronounced constriction in this region in some species. Ventrianal shield subtriangular to subrectangular, longer than wide, often eroded laterally or anteriorly, bearing 4–5 pairs of setae (rarely 2–3 pairs; none in T. chazdonae , which has oval anal shield, similar to female) in addition to circumanal setae. A pair of metapodal plates of variable shapes and sizes (no metapodal plate in T. analis (Fain & Hyland) , known only from male holotype). Opisthogastric setae often much longer than in female. Peritrematic shield fused or not to exopodal shield beside coxa IV. Peritreme usually reaching level of z1 but sometimes only level of s1. Leg II distinctly enlarged and curved; setae av of femur, genu, and usually also tibia enlarged, spine- or knob-shaped; setae av1–av3 and pv1 of tarsus modified, knob- or spine-shaped; dorsal setae of femur, genu and tibia sometimes distinctly longer than width of respective segments; setae ad1 and pd1 sometimes barbed. Tarsus of leg III with av2 always, and pv1 and av3 usually, modified, knob-shaped. Leg setation as in female.

NOTE: dimorphism of adult males reported for T. erioxynon , involving mostly variation in ornamentation of idiosomal setae (smooth or ornamented) and lengths of setae (idiosomal setae shorter than distance to subsequent setae or most idiosomal setae longer than distance to subsequent setae).