Lasioseius fuscina, Moraza & Lindquist, 2018

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 : 83-87

Lasioseius fuscina n. sp. ( Figures 8 , 9 , 11C , 12D , 13 E-F, 14D)

Zoobank: F088E970-F8B8-4E76-8382-87DA2EF12B7F

Diagnosis — Adult female: Sternal shield lineated laterally and anteromedially, its anterior margin with blunt medial projection, its posterolateral corners not emarginated; poroids iv3 and setae st4 on slender metasternal platelets; epigynal shield reticulated over nearly entire surface, its lateral margins concave, narrowed anterior to setae st5; ventrianal shield with posterolateral margins on either side of anus nearly parallel, and with four pairs of opisthogastric setae, JV1 on shield; metapodal plates nearly connected or coalesced on each side. Dorsal setae r6 on edge of dorsal shield; Z5, S5 attenuated like adjacent setae. Adult male: Sternitigenital shield incompletely reticulated, nearly smooth medially. Dimorphic leg setal structures minimal. Adult attributes: Gnathotectum anterior margin with 3 elongated, denticulated tines. Fixed chela with file of 8-9 teeth in female, ca 4 in male. Sternal setae st1 inserted on anterior edge of sternal shield. Tarsi II-IV with ventral apical process bluntly pointed, smooth apically; tarsi II-III with setae (l-1) shorter, more spinelike than (v-1); tarsus IV with distal seta pv-1 longer, more attenuate than av-1, (l-1); pretarsus with anterior paradactylus slightly longer than posterior one.

Description

Idiosomatic dorsum — Adult female. Dorsal shield 424 – 450 long, 201 – 245 wide at level of r3, 267 – 296 wide at level of r6 (n=7), lightly reticulate-lineate on lateral surfaces but nearly smooth medially between bases of setae j4 to J4, and sparsely punctate behind level of setae Z4; shield with 38 pairs of setae generally similar in size and acutely pointed form, with few apical barbs, more so on Z4, Z5, S4, S5 ( Figs 8A, B ); J1-J3 and Z1-Z4 slightly longer than longitudinal intervals between their bases, S2-S4 clearly so; J5 minute, barbed (4 – 6): j1 (28 – 31), j2 (26 – 32), j3 (41 – 44), j4 (26 – 32), j5 (32 – 35), j6 (45 – 47), z1 (19 – 24), z2 (30 – 35), z3 (37 – 42), z4 (41 – 45), z5 (32 – 37), z6 (41 – 46); s1 (32 – 38), s2 (34 – 43), s3 (40 – 45), s4 (43 – 48), s5 (45 – 50), s6 (47 – 52), r2 (35 – 42), r3 erect (21 – 30), r4 (32 – 48), r5 (32 – 50), r6 (32 – 48), J1 (32 – 42), J2 (40 – 50), J3 (43 – 52), J4 (43 – 52), Z1 (48 – 51), Z2 (51 – 54), Z3 (54 – 58), Z4 (58 – 62), Z5 (63 – 70), S1 (43 – 50), S2 (44 – 53), S3 (46 – 58), S4 (46 – 58), S5 (43 – 52). Lateral soft cuticle with seven pairs of smooth setae, including R1 (40 – 48), R2-R6 (35 – 42) and ZV5 posteriorly (30 – 33) ( Fig. 8D ). Peritrematal shield fused to dorsal shield at level of s1.

Adult male. Dorsal shield 338 – 340 long, 185 – 200 wide at level of setae r3, 200 – 215 wide at level of r6 (n = 2); shield ornamentation, complement of pore-like structures and setation as in female except slightly more expanded laterally so as to become united with peritrematal shields at level of setae s2 and bear setae R1. Dorsal shield with 39 pairs of setae, their attenuated form and relative lengths as in female. Setae j1 (21 – 23), j2 (16 – 26), j3 (35 – 36), j4 (21 – 25), j5 (24 – 25), j6 (32 – 33), z1 (14 – 16), z2 (22), z3 (32), z4 (34 – 35), z5 (27 – 28), z6 (32 – 36), s1 (29 – 30), s2 (30 – 31), s3 (34 – 38), s4 (36), s5 (42), s6 (35 – 36), r2, r4, r5 (33 – 37), r3 erect, shorter (23 – 27), r6 (36 – 38), J1-J3 (27 – 32), J4 (25 – 27), J5 (3 – 4), Z1-Z2 (40 – 43), Z3 (44 – 45), Z4, Z5 longest (48 – 54), S1, S2 (35 – 41), S3 (41 – 45), S4 (40

– 43), S5 (32 – 35). Lateral soft cuticle with six pairs of setae, R2-R6 (27 – 37) followed by ZV5.

Idiosomatic venter — Adult female. Tritosternum base 26 – 28 long and 10 – 14 wide at its base, with paired laciniae fused for about 33 – 37 of entire length (96 – 100). Presternal region with circumscribed pair of jagged-lineate, granulated areas adhered to anterior margin of sternal shield, sometimes flanked anteriorly by a pair of narrow slightly sclerotized strips on either side of tritosternum base. Sternal shield 87 – 93 long from slight, blunt medial projection of anterior margin to gently concave posterior margin, 85 – 95 wide, weakly reticulate-lineate over much of surface or nearly smooth medially, with arcuate transverse line between poroids iv1 ( Fig. 8D ); sternal shield setae of similar lengths, st1 (15 – 20), st2, st3 (11 – 16). Sternal poroids iv3 and setae st4 (6 – 14) inserted together on small metasternal platelets (15 – 20). Endopodal strips narrow between coxae III and IV. Epigynal shield lightly reticulate over entire surface, its narrowly rounded hyaline margin nearly reaching or slightly overlapping posterior edge of sternal shield, its lateral margins concave, narrowed anterior to setae st5 (11 – 15), and its posterolateral corners slightly emarginated behind st5; shield 140 – 147 long, 78 – 87 at widest level at posterior rounded corners, 66 – 71 at level of st5, and 49 – 54 at narrowest width between legs IV. Opisthosomatic venter with two pairs of metapodal platelets touching or coalesced on each side, primary pair ovoid to subtriangular, 20 – 25 long, 10 – 12 wide, secondary pair smaller, greatest transverse dimension 8 – 12. Ventrianal shield inversely subtriangular with irregularly rounded anterior corners, with posterolateral margins on either side of anus nearly parallel; surface entirely lightly sculptured, with primarily transverse lineation changing to reticulation behind setae JV2-ZV2, except anal region sparsely punctate on either side of postanal seta; shield wider (160 – 183) than long including cribrum (136 – 147), width at anal level (95 – 104); gland pore gv3 on shield edge posterior to anal opening; shield with four pairs of ventral setae: JV1 (12 – 17), JV2 (22 – 27), JV3 (24 – 31), ZV2 (22 – 27); with paranal setae (11 – 14) shorter than postanal seta (28 – 35). Soft cuticle with four pairs of simple opisthogastric setae, ZV1 (11 – 15) anterior to ventrianal shield, ZV3 (17 – 22), JV5 attenuated, barbed (48 – 55) flanking the shield, and ZV5 (30 – 33) somewhat aligned behind R6; three pairs of poroids (including ivp) on soft opisthogastric cuticle, ivo2 sometimes captured on anterolateral edge of ventrianal shield. Peritrematal-exopodal shield with lines extending from stigma into rounded posterior margin ( Fig. 8D ); peritreme extending to level between setae s1 and z1 ( Fig. 8A ). Spermathecal apparatus with cup-like calyx (12 – 15 long including embolus).

Adult male. Tritosternum much as in female, but with base biarticulate, wider (6 – 11) than long (5 – 10), and laciniae (37 – 40) fused (8) for only about 1/5 of total length. Presternal region weakly ornamented, sometimes with pair of narrow strips on either side of tritosternum base. Sternitigenital shield length 158 – 162 from genital opening, widths 65 – 72 at level between coxae II, 50 between coxae IV; shield with a concave arcuate line between poroids iv1, lightly lineate-reticulate along lateral margins and posteriorly between coxae IV, unornamented medially between st2 and iv3, with endopodal apices freely acuminate beside coxae IV; setae st1-st5 of dissimilar lengths as in female, st1 (14 – 16), st2 (11 – 12), st3 (8 – 11), st4 shorter (4 – 8), st5 (7 – 8). Ventrianal shield reticulate as in female, its convex anterolateral margins entire behind apices of exopodal strips behind coxae IV, and posterolateral margins not constricted in anal region, its greatest width (173 – 189) larger than its length (123 – 141, including cribrum ca. 3 – 8 long, 73 – 80 wide); shield with seven pairs of opisthogastric setae, JV1, ZV1 (10 – 12), JV2, JV3 (25 – 29), ZV2 (20 – 26), ZV3 (17 – 20), and longest JV5 (40 – 43); postanal seta smooth (26 – 28), about three times as long as paranal setae (8 – 12) ( Fig. 9A ). Soft opisthogastric cuticle with two pairs of lyrifissures including ivp.

Gnathosoma — Adult female. Gnathotectum anterior margin with three denticulate prongs of similar moderately elongate length or medial prong longer than laterals ( Fig. 8C ). Cheliceral shaft, excluding basal section, 139 – 155 long, with slender digits; dorsal seta simple (10 – 11); fixed digit with tiny subapical tooth and row of 7-10 fine teeth, pilus dentilis minute, at level of 3 rd apical tooth; movable digit (48 – 51) tridentate ( Fig. 8E ). Subcapitulum with deutosternal rows differing little in width, most anterior row with 9-10 teeth, nd 2 to 5 th rows with 8-15 teeth, basalmost two rows slightly wider, with ca 15-20 teeth ( Fig. 8F ); subcapitular setae hp1 (40 – 50) about as long as capitular setae pc (40 – 46), longer than hp3 (27 – 29), and hp2 (20 – 22). Palp length (113 – 122), apical margin of palptrochanter with two or usually three spines anterolaterally; palptrochanter with internal seta v1 sickle-shaped, longer (35 – 44) and thicker than v2 (24 – 30) ( Fig. 8G ).

Adult male. Gnathotectum anterior margin with elongated prongs as in female ( Fig. 9B ). Cheliceral shaft, excluding short basal section 91 – 98 long; fixed digit with offset subapical tooth followed by pilus dentilis and sparse row of 4-5 small teeth ( Fig. 9E ); movable digit (27 – 28) unidentate; spermatodactyl 30 – 40 long, 3 – 6 wide at base, extending anteriorly ca 23 – 30 beyond apex of digit, with narrowed neck and small head apically ( Fig. 9D ). Corniculi slightly more widely spaced but not more arched than in female, 24 – 26 long, their bases flanked medially by pair of short (5 – 7) spiculate processes ( Figs 9C , 11C ); internal malae and labrum as in female. Subcapitulum with rows of deutosternal denticles much as in female, anterior five rows with ca 8-15 teeth, 6 th and 7 th rows with ca 15-20 teeth; hypostomatic setae hp1 (28 – 30) slightly attenuated, about as long as pc (24 – 31), longer than hp3 (20 – 21), and hp2 shortest (10 – 12) ( Fig. 9D ). Palpi (length 96 – 101) similar in structure, form of setae as in female; apical margin of palptrochanter with three spines anterolaterally; palptrochanter with inner seta (26 – 30) longer than outer seta (8 – 11) ( Fig. 9D ).

Legs — Adult female. Legs I (357 – 385) subequally as long as legs IV (360 – 380), and shorter than dorsal shield; other leg lengths (excluding pretarsi): II 286 – 319, III 288 – 303. Leg I pretarsus with biarticulated shaft (16 – 21 to base of claws), claws 10 – 12 long; tarsus (107 – 112) about 1.9-2.1 longer than tibia; other length ratios, femur (70 – 77): genu (50 – 52): tibia (52 – 60), about 1.3: 0.9: 1.0. Legs II, III with tarsus/tibia length ratio about 1.8-2.0, leg IV with that ratio about 1.9-2.0. Chaetotactic formulae of leg segments as given for species-group. Tarsi II-IV with ventroapical process (7 – 9) bluntly pointed, smooth apically ( Fig. 14D ), and with setae (d-1) (15 – 20) nearly as long as pretarsus to base of claws (17 – 20). Tarsi II-III with paradactyli reaching tips of tarsal claws, but tarsus IV with anterior paradactylus extending about 3-5 beyond claw ( Fig. 14D ). Tarsi II ( Fig. 13F ), III with setae (l-1) shorter (16 – 19), more spinelike than (v-1) (28 – 34); dorsal seta md (34 – 37) no longer than pd-2, pl-3, mv (34 – 35); setae al-2, ad-2 (36 – 41), pl-2 (43 – 44), al-3, (pd-3) (28 – 32); all tarsal setae smooth. Tarsus IV with distal setae v- (1) symmetrical in size (26 – 31), slenderer than somewhat spinelike (l-1) (15 – 22).

Adult male. Relative leg thicknesses and lengths, excluding pretarsi, similar to those of female, I 305 – 310, II 255 – 260, III 242 – 250, IV 302 – 305. Legs with segment length ratios as in female. Tarsus I pretarsus 10 – 15 to base of claws, claws 5 – 9 long. Tarsi II-IV with dorsoapical setal processes (d-1), ventroapical process and pretarsal structures formed as in female, pretarsus lengths 12 – 17 excluding claws (10) ( Fig. 13E ). Apical setal processes (d-1) (11 – 13) shorter than pretarsi to bases of claws (14 – 17). Dimorphic leg setal structures not apparent.

Type material — All specimens collected at the La Selva Biological Station, Heredia Province, Costa Rica (10°26´N, 84°01´W, elevation 50-150 m): HOLOTYPE: adult female, 12 June 1997, ex Heliconia sp. leaves, successional plots, coll. ALAS. PARATYPES: 1 adult female, 1 adult male, with same data as holotype; 1 adult female, 12 June 1997, ex coexistent adults of Cephaloleia belti Baly and C. ornatrix Donckier from Heliconia leaves, coll. ALAS; 3 adult females, 15 April 1994, ex adult Chrysomelidae , no host plant data, coll. M. Paniagua; 2 adult females, 18 February 1994, ex adult Chrysomelidae , no host plant data, coll. ALAS; 3 adult females, 1 adult male, date not indicated, ex adult Cephaloleia belti on Calathea leaf, coll. not indicated.

Host identifications — As noted for the records of Lasioseius serripes , the identities of the associated beetles given above are in accord with current molecular studies, which indicate that records of Cephololeia belti and C. ornatrix on Heliconia pogognatha are in accord with field diet records. While C. belti is a host generalist, C. ornatrix is a host specialist of Heliconia pogonantha ( Staines & Garcia-Robledo 2014, Garcia-Robledo et al. 2017).

Etymology — The specific name is based on the Latin noun,‘fuscina’, indicating a threepronged fork or trident, and refers to the elongated three-pronged gnathotectum characteristic of this species.

Remarks — Limited collection data indicate a possible host association preference for Cephaloleia belti , a plant host generalist. If so, the mite/host size would correlate, as adults of L. ‘fuscina’ are the smallest of the described mites of this species-group, and among species of Cephaloleia , beetles of C. belti are relatively small-sized as well, although those of C. ornatrix are mid-sized. However, collection data uncertainties must be kept in mind, as two of the collection samples for this species also included many adults of Lasioseius serripes , one of them as well with a few adults of L. cassidini which also co-occurred with fuscina in two other samples ( Table 1). Tentatively, subject to further studies, we conclude that, at La Selva, Lasioseius fuscina may be associated regularly with the host generalist Cephaloleia belti and to some extent with the host specialist C. ornatrix on Heliconia pogonantha .

Figures

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 9 Lasioseius fuscina n. sp., adult male: A – Idiosoma, ventral view; B – Gnathotectum; C – Subcapitulum and ventral setae of palptrochanter; D – Chelicera and spermatodactyl, ventral view; E – Detail of cheliceral fixed digit, ventral view.

Figure 11 Distal subcapitular region, adult males: A –L. cassidini; B – L. serripes; C. — L. fuscina

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).