Lasioseius (Lasioseius)

Moraza, Maria L. & Lindquist, Evert E., 2018, A new species-group with new species of the genus Lasioseius (Acari: Mesostigmata: Blattisociidae) associated with Neotropical hispine beetles in furled leaves ofHeliconia, Acarologia 58 (1), pp. 62-98 : 67-69

Key to species-groups of subgenus Lasioseius (Lasioseius) : females.

For a key to the genus and subgenera of Lasioseius , see the key to the world genera and subgenera of the subfamily Blattisociinae by Moraza and Lindquist (2011).

1. Dorsal shield lacking vertical j (1) and paravertical (z1) setae, leaving setae j2 as anteromedialmost pair, slightly behind level of paravertical poroids idj1; posterior region of dorsal shield with 10 or 11 pairs of setae, each of J, Z, S series with less than five pairs of setae; peritremes with anterior apices curving posteromedially above level of setae j2; female ventrianal shield with six pairs of opisthogastric setae; antiaxial face of fixed cheliceral digit with a subapical pointed process........ phytoseioides -group sensu Lindquist, 1964 and de Moraes et al., 2015

— Dorsal shield with setae j1 and usually z1 present, inserted at transverse level of poroids idj1 anterior to setae j2; posterior region of dorsal shield with 13 to 15 pairs of setae, at least the Z -series and usually all series complete with five pairs of setae each; peritremes with anterior apices not curving posteromedially where ending at level beside or short of setae z1; female ventrianal shield with two to six pairs of opisthogastric setae; antiaxial face of fixed cheliceral digit usually lacking a subapical process................................................2

2. Dorsal shield flanked by only two or three pairs of setae (marginals r5, R 1 and ventrolateral ZV5) on soft cuticle; dorsal shield with 16 pairs of setae, post-humeral pair r4 absent; tritosternum with laciniae fused for more than half their length; genua of legs I, II, III with 12, 9 or 10, 7 or 8 setae, respectively, each lacking one or two ventral setae.................................................................... porulosus -group sensu Walter and Lindquist, 1997

— Dorsal shield flanked by five to twelve pairs of setae (elements of marginals r5-6, R 1-6, submarginals UR, and ventrolateral ZV5) on soft cuticle; dorsal shield with 18 to 23 pairs of setae, usually including post-humeral pair r4; tritosternum with laciniae free for usually more than half their length; genua of legs I, II, III usually with 13, 11, 9 setae, respectively, each usually including holotrichous set of 3, 2, 2 ventral setae................................. 3

3. Dorsal shield setae collectively simple (imperceptibly or vestigially tricarinate); setae j2 nearly aligned transversely with j1 and z1; peritremes reach at most to level slightly beyond setae s1 (but not to paravertical setae z1); palptarsus with hyaline anterolateral flap extending from base of apotele to base of cluster of apical setae....................... cassidini -group

— Dorsal shield setae variable in form, but with at least setae j1, r3, Z5 usually tricarinate or tricarinate-pectinate; setae j2 inserted clearly behind transverse level of setae j1 and z1; peritremes variable in extent, but usually reaching to insertions of paravertical setae z1, anteriorly beyond setae s1; palptarsus lacking hyaline flap near base of apotele...................... 4

4. Dorsal shield with post-humeral seta r4 short, simple, similar to r2, and not more than half as long as tricarinate seta s4 neighboring it medially; most dorsal setae tricarinate and moderately long, nearly as long as longitudinal intervals between their bases; anterior pair of sternal setae on weakly sclerotized presternal area, just before anterior margin of sternal shield; sternal shield with anteromedial patch of reticula; tarsus II with one midlateral seta, pl-2, elongated, reaching nearly to base of pretarsus............. floridensis -group sensu Mineiro et al., 2009

— Dorsal shield with seta r4 usually similar in weakly to strongly tricarinate form and over half as long as adjacent seta s4; dorsal setae variable in form and lengths; anterior pair of sternal setae on or off well sclerotized surface of sternal shield; sternal shield variably ornamented; tarsus II with or without one or two attenuated setae........................................................... many other species and undescribed groups of subgenus L. ( Lasioseius )

Key to species of Lasioseius cassidini species-group: females.

1. Ventrianal shield with 3 pairs of ventral setae, JV1 on soft cuticle ( Fig. 5E ); sternal shield reticulate over entire surface; setae st4 and poroids iv3 on soft cuticle ( Fig. 5E ); metapodal platelets connected or coalesced on each side ( Fig. 5E ); tarsi II-IV with ventroapical process truncate-spiculate apically ( Figs 13G , 14B )............................... L. serripes n. sp.

— Ventrianal shield with 4 pairs of ventral setae, JV1 on shield ( Fig. 8D ); sternal shield smooth, or weakly lineate along lateral margins; setae st4 and usually poroids iv3 on metasternal platelets; metapodal platelets separate on each side; tarsi II-IV with ventroapical process bluntly pointed, smooth apically ( Figs 13H , 14A, C, D ).................................. 2

2. Gnathotectum with three elongated tines ( Fig. 8C ); fixed chela with 9-13 teeth ( Fig. 8E ); smaller mites, dorsal shield length less than 470μm........................ L. fuscina n. sp.

— Gnathotectum with three short broad tines or irregularly truncate-serrate; fixed chela with 18-28 fine teeth ( Fig. 10G ); larger mites, dorsal shield length more than 530μm........... 3

3. Setae Z5, S5 thickened, blunt-tipped in distinction to other attenuated dorsal setae ( Fig. 10A, B ); gnathotectum with three short broad tines ( Fig. 10D ); poroids iv3 and setae st4 together on slender metasternal platelets ( Fig. 10C )............................. L. duobtusisetis n. sp.

— Setae Z5, S5 not conspicuously thicker or blunter than other dorsal setae; gnathotectum truncate-serrate ( Fig. 1D ); poroids iv3 alone on soft cuticle or with setae st4 on slender metasternal platelets.................................................................. 4

4. Sternal setae st4 on tiny metasternal plates, leaving sternal poroids iv3 on soft cuticle ( Fig. 1C ); sternal setae st1 on weakly sclerotized presternal region ( Fig. 1C ); podonotal region of dorsal shield with 23 pairs of setae, including r6; tarsus IV with distal seta av-1 ca 1.3 longer than pv-1 and 2.5 times longer than slender setae l- (1) ( Fig. 14A ).......... L. cassidini n. sp.

— Sternal poroids iv3 with sternal setae st4 on slender metasternal platelets (as in Fig. 8D ); sternal setae st1 on anterior margin of sternal shield; podonotal region of dorsal shield with 22 pairs of setae, r6 on soft cuticle; tarsus IV with distal seta av-1 enlarged, erect, 2.5 times longer than pv-1 and 4 times longer than short, slender setae l- (1) ( Fig. 12H )............................................................. Lasioseius sp. (undescribed) ex Chelobasis bicolor

Figures

Figure 1 Lasioseius cassidini n. sp. adult female: A – Idiosoma, dorsal view; B – Detail of denoted dorsal setae; C – Idiosoma, ventral view; D – Gnathotectum; E – Subcapitulum; F – Spermathecal structures; G – Fixed cheliceral digit in ventral view; H – movable cheliceral digit in partially lateral view.

Figure 5 Lasioseius serripes n. sp., adult male: A – Idiosoma, dorsal view; B – Gnathotectum; C – Tritosternum; D – Subcapitulum and ventral setae of palptrochanter; E – Idiosoma, ventral view; F – Chelicera and spermatodactyl, ventrolateral view; G – Detail of fixed cheliceral digit, ventral view; H – Detail of spermatodactyl.

Figure 8 Lasioseius fuscina n. sp., adult female: A – Idiosoma, dorsal view; B – Detail of denoted dorsal setae; C – Gnathotectum; D – Idiosoma, ventral view; E – Cheliceral digits, paraxial view; F – Subcapitulum; G – Detail of ventral setae of palptrochanter.

Figure 10 Lasioseius duobtusisetis n. sp., adult female: A – Idiosoma, dorsal view; B – Detail of denoted dorsal setae; C. Idiosoma, ventral view; D – Gnathotectum; E – Subcapitulum and ventral setae of palptrochanter; F – Spermathecal structures; G – Detail of cheliceral fixed digit, ventral view.

Figure 12 A-D – Leg II, dorsal view (right leg, excluding tarsus, coxa and trochanter), adult males: A—Lasioseius serripes n. sp.; B – L. serripes, detail of ventral setaeon genu and tibia III; C –Lasioseius cassidini n. sp.; D – Lasioseius fuscina n. sp. E, F – Lasioseius duobtusisetis, adult female, tarsus I right leg, dorsal view: E – General aspect without detail of dorsodistal sensorial area; F – Detail of dorsodistal sensorial area. G – Lasioseius serripes, protonymph, tarsus IV left leg; H — Lasioseius sp. undescribed. adult female, tarsus IV right leg, ventral view. (Solid black setae in figures A-G and solid black circles in figures G and H indicate dorsal setae).

Figure 13 Tarsus II, right leg. A, B, H.Lasioseius cassidini n. sp.: A – Adult female, dorsal view; B – Adult male, dorsal view; H — Detail of distal region, lateroventral view. C, D, G.Lasioseius serripes n. sp.: C – Adult female, dorsal view; D – Adult male, anterolateral view; G. Detail of distal region, ventral view. E, F.Lasioseius fuscina n. sp.: E – Adult male, dorsal view; F – Adult female, dorsal view. I —Lasioseius duobtusisetis n. sp., adult female, dorsal view. (Solid black color indicates dorsal setae on segment).

Figure 14 Tarsus IV, adult females, right leg, ventral view: A –Lasioseius cassidini n. sp.; B – Lasioseius serripes n. sp.; C – Lasioseius duobtusisetis n. sp.; D – Lasioseius fuscina n. sp. (solid black circles indicate dorsal setae insertions).