Cheiroseius luizgonzagai, De Moraes, 2017

De Moraes, Gilberto J., 2017, Two new species of Cheiroseius Berlese (Acari: Blattisociidae), with a key for identification of the species from Brazil, Zootaxa 4324 (1), pp. 108-120 : 109-113

Cheiroseius luizgonzagai n. sp.

Diagnosis (Female): Dorsal shield smooth; podonotal region of dorsal shield with 22 pairs of setae; opisthonotal region with 14 pairs of setae. Unsclerotised cuticle along marginal of dorsal shield with one pair of setae; presternal area without platelets. Ventrianal shield subtrapezoidal, reticulate over nearly its entire surface, with two pairs of setae in addition to circumanal setae; all legs with pretarsi and claws. Median section of pulvilli of legs II– IV as well as paradactyli of these legs acuminate.

Material examined. Holotype female, nine paratype females and one paratype male from floating Salvinia herzogii (Salviniaceae) at Crato (07°19'55''S and 39°55'.51''W), State of Ceará, Brazil; collected by G.J. Moraes and I.P. Furtado on December 13, 2012; deposited at Departamento de Entomologia e Acarologia, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, State of São Paulo, Brazil.

Adult female ( Figs 1–9 ) (nine specimens measured).

Gnathosoma. Antiaxial and dorsal lyrifissures as well as dorsal seta distinct; fixed cheliceral digit 39 (38–39) long, with one tooth in addition to apical tooth and a setiform pilus dentilis 15 (14–15), movable cheliceral digit 40 (39–40) long with one tooth in addition to apical tooth ( Fig. 1 ). Palp setae (trochanter to tibia): 2–5–6–13; setae aciculate and smooth, except al 1 and al 2 of palp genu, spatulate and smooth ( Fig. 2 ); seta v 2 of palp trochanter elongate ( Fig. 4 ). Anterior region of epistome with 2–3 extensions, each 1–3 tined, the median extension slightly longer or about as long as others ( Fig. 3 ). Deutosternal region not delimited by lateral lines, with seven transverse rows of teeth, about parallel to each other, each bearing 8–22 small teeth; corniculus horn-like, reaching nearly mid-level of palp femur; setae h 2 inserted slightly posteriad of h 3 ( Fig. 4 ). Measurements of setae: h 1 31 (31–32), h 2 12 (11–13), h 3 20 (19–20), pc 22 (21–25).

Dorsal idiosoma ( Fig. 5 ). Idiosoma 284 (275–290) long and 177 (170–190) wide at widest point. Podonotal and opisthonotal shields fused and smooth. Podonotal region with 22 pairs of setae (j 1– j 6, z 1– z 6, s 1– s 6, r 2– r 5), four pairs of distinguishable lyrifissures and three pairs of pores. Opisthonotal region with 14 pairs of setae (J 1– J 5, Z 1– Z 5, S 1, S 3– S 5), seven pairs of distinguishable lyrifissures and two pairs of pores. Unsclerotised cuticle along lateral margins of opisthonotal region with one pair of setae (R 1). Measurements of setae: j 1 21 (20–22), j 2 16 (15– 16), j 3 18 (16–18), j 4 19 (18–20), j 5 19 (18–20), j 6 17 (16–17), J 1 17 (16–18), J 2 16 (15–16), J 3 16 (15–17), J 4 17 (16–17), J 5 v 5 (5–6), z 1 9 (8–10), z 2 16 (14–18), z 3 16 (16–17), z 4 17 (18–19), z 5 16 (15–16), z 6 18 (16–19), Z 1 17 (17–18), Z 2 17 (16–18), Z 3 16 (15–17), Z 4 19 (19–20), Z 5 20 (20–21), s 1 14 (13–14) , s 2 15 (15–16), s 3 16 (15– 17), s 4 17 (16–17), s 5 17 (16–18), s 6 14 (13–15), S 1 17 (15–18), S 3 18 (17–19), S 4 19 (17–20), S 5 20 (18–21), r 2 15 (15–16), r 3 16 (15–16), r 4 15 (14–15), r 5 16 (15–16), R 1 13 (12–15). None of the idiosomal setae inserted on tubercles and slightly shorter than distance to subsequent setae of the same series; all setae smooth.

Ventral idiosoma ( Fig. 6 ). Base of tritosternum 16 (16–17) long and 14 (13–15) wide proximally; laciniae 85 (84–85), separated for about 40% of their total length, pilose along separated section ( Fig. 7 ). Pre-sternal area without platelets. Sternal shield 50 (48–53) long at mid-line and 62 (60–63) wide between coxae II and III; slightly striate laterally, smooth elsewhere; posterior margin concave; with three pairs of setae and two pairs of lyrifissures; with prominent endopodal projections between coxae I and II. Third pair of sternal lyrifissures and sternal setae st 4 on metasternal plates. Genital shield smooth over most of its extent; posterior margin truncate; distance between st 5– st 5 39 (38–40). Unsclerotised cuticle with a pair of lyrifissure (iv 5) posterolaterad of st 5; pore gv 2 inserted on peritrematic plate behind coxa IV. Metapodal plates indistinguishable. Ventrianal shield subtrapezoidal, reticulate over nearly its entire surface, 80 (75–90) long at mid-line and 101 (98–100) wide at widest level; with two pairs of setae (Jv 3 and Zv 2) in addition to circumanal setae, which are smooth and pointed, and one pair of distinguishable pores near margin, posteromesad of Jv 3; para-anal setae lightly longer than post-anal seta and inserted at level of mid-length of anal opening. Four or six elongate platelets present between genital and ventrianal shields. Five pairs of opisthogastric setae on unsclerotised cuticle flanking ventrianal shield (Jv 1, Jv 4, Jv 5, Zv 3 and Zv 5). Measurements of setae: st 1 16 (15–17), st 2 17 (17–18), st 3 18 (16–19), st 4 9 (9–10), st 5 16 (16–17); Jv 1 14 (12– 15), Jv 3 14 (12–15), Jv 4 12 (10–15) Jv 5 15 (14–16), Zv 2 12 (11–13), Zv 3 12 (11–13), Zv 4 10 (10–11), Zv 5 10 (10– 11); para-anal 21 (20–24), post-anal 16 (16–17).

Peritreme and peritrematic plate. Peritreme broad and elongate, extending anteriorly to the level of j 1; anterior region dorsally visible, posteriorly beyond behind stigma and curved inward behind coxa IV. Exopodal plate fragmented, represented by a subtriangular platelet between coxae I–II and II–III, and fused to peritrematic plate posteriad of stigma. Peritrematic plate fused with dorsal shield anterior to r 2, posteriorly behind coxa IV; with a pair of distinguishable lyrifissures and a pair of pores behind the stigma ( Figs 5, 6 ).

Spermathecal apparatus. Not distinguishable.

Legs. All legs with pretarsi and claws. Median section of pulvilli of legs II–IV as well as paradactyli of these legs acuminate ( Fig. 8 ). Lengths: I: 316 (310–330), II: 230 (228–235); III: 213 (210–220); IV: 260 (255–265); tarsus I: 103 (102–105), tibiae I: 137 (42–50). Chaetotaxy/setation – coxae: I: 0, 0/1, 0/1, 0; II: 0, 0/1, 0/1, 0; III: 0, 0/1, 0/1, 0; IV: 0, 0/1, 0/0, 0; trochanters: I: 1, 0/1,1/2, 1; II: 1, 0/1, 1/2, 0; III: 1, 1/2, 0/1, 0; IV: 1, 1/1, 0/2, 0; femora: I: 2, 3/1, 2/2, 1; II: 2, 3/1, 2/1, 1; III: 1, 2/1, 1/0, 1: IV: 1, 2/1, 1/0, 1; genua: I: 2, 3/2, 2/1, 2; II: 2, 3/1, 2/0, 2; III: 2, 2/1, 2/0, 1; IV: 2, 2/1, 3/0, 1; tibia: I: 2, 3/2, 2/1, 2; II: 2, 1/1, 2/1, 2; III: 2, 1/1, 2/1, 1; IV: 2, 1/1, 3/1, 2; tarsi I: not counted, II: 18; III: 18; IV: 18. All legs with smooth setae; tarsi of legs II–IV, but not other segments, with some setae much longer than others ( Fig. 9 ).

Adult male ( Figs 10–13 ) (One specimen measured).

Gnathosoma. Antiaxial and dorsal lyrifissures as well as dorsal seta distinct; fixed cheliceral digits 30 long, with one tooth in addition to apical tooth and the base of the pilus dentilis (actual pilus dentilis not visible), movable cheliceral digit 30 long with one tooth in addition to apical tooth ( Fig. 10 ); spermatodactyl 27 long, almost straight; palp chaetotaxy, deutosternal region and position of hypostomal setae as in adult female. Anterior region of epistome with three extensions, each with 2–3 distal points, the median slightly longer than others ( Fig. 11 ). Measurements of setae: h 1 32, h 2 17, h 3 13, pc 18; shape of setae as in adult female.

Dorsal idiosoma ( Fig. 12 ). Idiosoma 210 long and 164 wide at widest point. Dorsal shield similar to that of adult female; however, opisthonotal region with 15 pairs of setae (J 4 absent and R 1 present in the shield). Measurements of setae: j 1 12, j 2 12, j 3 16, j 4 18, j 5 17, j 6 16, J 1 13, J 2 13, J 3 15, J 5 5, z 1 6, z 2 15, z 3 14, z 4 16, z 5 12, z 6 15, Z 1 15, Z 2 13, Z 3 13, Z 4 13, Z 5 21, s 1 12, s 2 12, s 3 13, s 4 13, s 5 12, s 6 13, S 1 17, S 2 15, S 3 18, S 4 18, S 5 20, r 2 10, r 3 14, r 4 15, r 5 15, R 1 13; shape of setae as in adult female.

Ventral idiosoma ( Fig. 13 ). Base of tritosternum 14 long and 10 wide proximally; laciniae 80, separated for about 40% of their total length, pilose along separated section. Pre-sternal area smooth. Sternogenital shield lightly striate laterally, smooth elsewhere; 95 long at mid-line and 52 wide between setae st 1 and st 2, posterior margin slightly concave; with four pairs of setae and three pairs of lyrifissures (without st 4). Ventrianal shield reticulated over most of its surface, fused with the peritrematic plate, 82 long at mid-line and 110 wide at widest point; with two pairs of setae (Jv 2 and Jv 3) in addition to circumanal setae, one pair of distinguishable lyrifissures and one pair of pores. Post-anal seta slightly shorter than para-anal seta, the latter inserted at level of mid-length of anal opening. Metapodal plates absent, with two pairs of opisthogastric setae (Jv 5 and Zv 5) flanking ventrianal shield. Measurements of setae: st 1 13, st 2 14, st 3 14, st 5 12, Jv2 11, Jv 3 11, Jv 5 12, Zv 5 12, para-anal 16, post-anal 10; shape of setae as in adult female.

Peritreme and peritrematic plates. Peritreme broad, not visible dorsally, but otherwise similar to that of female. Peritrematic and exopodal plates similar to adult female ( Fig. 13 ).

Legs. Lengths: I: 279; II: 290; III: 178; IV: 185. Numbers of setae of leg segments and shape of setae as in adult female. All legs with pretarsi, similar to those of adult female.

Etymology. This species is named in memory of Luiz Gonzaga, one of the most famous Brazilian artists, born near the type locality of this species.

Remarks. The positions of some of the leg setae in this species are unusual in comparison with what has been reported for other free-living Mesostigmata ( Evans, 1963) , as follows: av 2, pv 2 and md of leg II and pv 2 and md of leg III more basal. Given the uniqueness of the insertions of setae of tarsus IV anteriad of mv, names of those setae were not assigned in the illustration.

Two characteristics of this species are more typical of Platyseius , namely the smooth dorsal shield (in Cheiroseius , only reported in Cheiroseius greeneae ( De Leon, 1964) , as “practically” smooth) and the presence of only nine setae on tibia II (not mentioned for any Cheiroseius species). However, several other characteristics of this new species are typical of Cheiroseius , such as the presence of five pairs of J setae, st 1 about as long as st 3, distance between fourth and fifth transverse row of deutosternal denticles about the same as distance between fifth and sixth rows, only 12 setae on genu and tibia I (found in some Cheiroseius ), male with only two pairs of opisthogastric setae in addition to circumanal setae (minimum of five in Platyseius and three in Cheiroseius ). Cheiroseius luizgonzagai resembles C. greeneae by the smooth dorsal shield, but the latter differs from the new species by several characteristics, including the much longer dorsal shield setae, presence of three pairs of opisthogastric setae on ventrianal shield in addition to the circumanal setae, absence of peritrematic extension behind stigma, with a pair of metapodal plates. The new species is also similar to Cheiroseius cyclanalis Ma, 2000 , but females of the latter have dorsal shield at least partially ornamented, ventrianal shield smaller (width of the shield distinctly smaller than distance between inner margins of coxae IV) and roundish and with a pair of metapodal plates.

Figures

FIGURE 9. Cheiroseius luizgonzagai n. sp. paratype female. Tarsus II-IV. Lyrifissures enlarged for improved visibility.

FIGURES 1 – 8. Cheiroseius luizgonzagai n. sp. holotype female. 1. Lateral (antiaxial) view of chelicera; 2. Palp trochanter; 3 Epistome; 4. Hypostome; 5. Dorsal idiosoma; 6. Ventral idiosoma; 7. Tritosternum. 8. Paradactyli of legs II-IV. Lyrifissures enlarged for improved visibility.

FIGURES 10 – 13. Cheiroseius luizgonzagai n. sp. paratype male. 10. Lateral (antiaxial) view of chelicera; 11. Epistome; 12. Dorsal idiosoma; 13. Ventral idiosoma. Lyrifissures enlarged for improved visibility.