Lasioseius serripes, 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 : 74-83

Lasioseius serripes n. sp. ( Figures 3-7 , 11B , 12A, B, G , 13 C-D, 14B)

Zoobank: F1A4EE0C-0031-410D-B993-20CDC3D08D71

Diagnosis — Adult female: Sternal shield reticulated over entire surface, its posterolateral corners emarginated lateral to setae st3; poroids iv3 and setae st4 on soft cuticle; epigynal shield fully reticulated, its lateral margins parallel anterior to setae st5; ventrianal shield with posterolateral margins on either side of anus divergent, and with three pairs of opisthogastric setae, JV1 on soft cuticle; metapodal plates connected or coalesced on each side. Dorsal setae r6 usually on soft cuticle; Z5, S5 attenuated like adjacent setae. Adult male: Sternitigenital shield reticulated over entire surface. Leg II with dorsal setae dimorphically short, blunt on genu, tibia, tarsus. Tibiae III-IV with seta pv dimorphically hooked, blunt. Adult attributes: Gnathotectum anterior margin truncate, irregularly denticulate. Fixed chela with file of ca 20 teeth in female, ca 18 in male. Sternal setae st1 inserted on anterior edge of sternal shield. Tarsi II-IV with ventroapical process truncate-spiculate apically; tarsi II-III with seta av-1 slightly longer and thicker at base than pv-1 and both slightly longer than l- (1); tarsus IV with apical setae (v-1) symmetrically thicker than, and about twice as long as d- (1); pretarsal paradactyli small, symmetrical.

Description

Idiosomatic dorsum — Adult female: Dorsal shield 651 – 695 long, 337 – 385 wide at level of r3, 368 – 397 wide at level of r5 (n=9), lightly reticulated over entire surface, more faintly so behind setae Z4, where also faintly punctate. Shield with 37 pairs of setae, all acutely pointed ( Figs. 3A, B ), with few barbs, except J5 short (15 – 17), clearly barbed; J1-J4 about as long as longitudinal intervals between their bases, Z1-Z4 and S2-S4 longer than intervals between their bases; r3 erect, similarly as long as r2, r4: j1 (41 – 50), j2 (45 – 55), j3 (60 – 70), j4 (43 – 50), j5 (48 – 55), j6 (58 – 63), z1 (20 – 29), z2 (50 – 55), z3 (52 – 60), z4 (64 – 70), z5 (47 – 55), z6 (60 – 70), s1 (48 – 55), s2 (50 – 60), s3 (53 – 65), s4 (64 – 70), s5 (63 – 75), s6 (57 – 72), r2 (50 – 60), r3 (54 – 62), r4 (55 – 62), r5 (56 – 67), J1 (45 – 55), J2-J4 (48 – 62), Z1-Z3 (71 – 97), Z4 (87 – 102), Z5 (70 – 88), S1 (57 – 70), S2 (66 – 77), S3 (64 – 75), S4 (66 – 78), S5 (64 – 75). Lateral soft cuticle with eight pairs of smooth setae, including r6 (52 – 62), R1 (48 – 55), R2-R6 (44 – 52) and ZV5 (43 – 47) posteriorly.

Adult male. Dorsal shield 557 – 587 long, 332 – 357 wide at level of setae r3, 325 – 353 wide at level of r6 (n = 5); 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 marginal setae r6 and sometimes R1 ( Fig. 5A ). Dorsal shield with 37-38 pairs of setae, their form and relative lengths as in female, except bases of Z4, Z5, S4, S5 swollen sub-basally. Setae j1 (28 – 33), j2 (40 – 43), j3 (53 – 60), j4 (38 – 40), j5 (38 – 47), j6 (48 – 54), z1 (17 – 20), z2, z3 (45 – 50), z4 (55 – 60), z5 (38 – 44), z6 (50), s1 (46 – 48), s2 (52 – 56), s3 (50 – 61), s4 (58 – 65), s5 (58 – 65), s6 (55 – 58), r2-r4 (48 – 53), r5 (57 – 60), r6 (50 – 52), J1-J4 (40 – 47), J5 (9 – 12), Z1-Z3 (66 – 75), Z5 (61 – 72), S1 (50 – 52), S2 (55 – 57), S3-S5 (57 – 66), Z4 the longest opisthonotal setae (75 – 86). Lateral soft cuticle with usually six pairs of marginal setae (40 – 47). Form of peritrematal shields as in female.

Idiosomatic venter — Adult female. Tritosternum base 28 – 33 long, 16 – 20 wide at its base, with paired laciniae fused along basal 15 – 22 of entire length (95 – 115). Presternal region with circumscribed pair of weakly lineated granulated areas adhered to anterior margin of sternal shield. Sternal shield 100 – 112 long, with irregularly concave posterior margin, 118 – 125 wide, well reticulated over entire surface, midsurface with narrower reticula; sternal setae of similar length, st1 (38 – 42), st2 (33 – 39), st3 (35 – 42). Sternal poroids iv3 and setae st4

(26 – 32) inserted on soft cuticle. Endopodal strips narrow between coxae III and IV. Epigynal shield well reticulated over entire surface, with narrower reticula anterior to insertion of st5

(36 – 42), its broadly rounded hyaline anterior margin not reaching posterior edge of sternal shield, its lateral margins nearly parallel anterior to setae st5, and its posterolateral corners slightly to clearly emarginated behind st5; shield 188 – 210 long, 95 – 107 at widest level at posterior angulate margin, 62 – 70 at narrowest width between legs IV. Opisthosomatic venter with two pairs of metapodal platelets connected or coalesced on each side, primary pair ovate, 25 – 30 long, 13 – 17 wide, secondary pair with greatest dimension transverse, 13 – 22; one adjacent set of small, narrow platelets near anterior margin of ventrianal shield, lateral to JV1. Ventrianal shield inversely subtriangular with rounded anterior corners, with posterolateral margins on either side of anus divergent anteriorly; surface strongly reticulate except faintly in anal region where also faintly punctate on either side of postanal seta; shield wider (253 – 295) than long (179 – 205), including cribrum (8 – 12); shield with three pairs of ventral setae and sometimes pores gv3: JV2 (33 – 40), JV3 (35 – 45), ZV2 (34 – 40); with paranal setae (20 – 27) shorter than postanal seta (49 – 62). Soft cuticle with six pairs of simple opisthogastric setae, JV1 and ZV1 (26 – 33) anterior to ventrianal shield, ZV3 (32 – 40), ZV4 (40 – 47), JV5 (55 – 65) flanking the shield, and ZV5 (43 – 47) aligned behind R6; three pairs of poroids (including ivp) and sometimes gland pore gv3 on soft opisthogastric cuticle. Peritrematal-exopodal shield with lines extending from stigma to irregularly rounded posterior margin ( Fig. 4A ); peritreme extending to level slightly anterior to insertion of setae s1 ( Fig. 3A ). Spermathecal apparatus with cup-like calyx ca. 30 – 35 long from atrium at base, 23 – 26 wide at distal margin ( Fig. 3D).

Adult male. Tritosternum much as in female, but with base biarticulate, longer (21 – 24) than wide (13 – 17), and laciniae (78 – 88) fused along basal 10 – 12 of entire length ( Fig. 5C ). Presternal region weakly granulated, with or without pair of weakly sclerotized transverse strips anteriorly. Sternitigenital shield length 245 – 283 from anterior margin of genital opening, widths 104 – 110 at level between coxae II, 92 – 100 between coxae III, and 58 – 71 between coxae IV; shield nearly fully reticulated, but bare near posterior margin where endopodal apices freely truncated beside coxae IV; shield medial region more weakly ornamented but punctate between setae iv1 and st3, and with poroids iv3 appearing as distinctively rounded pits; setae st1 on anterior margin of sclerotized region of shield; setae st1-st5 of dissimilar lengths as in female, st1-st3 (27 – 30), st4 shortest (20 – 23) and st5 longest (30 – 35). Ventrianal shield strongly reticulate as in female, its greatest width (282 – 305) larger than its length (178 – 220, including cribrum ca. 9 – 11 long, 75 – 86 wide); shield with seven pairs of opisthogastric setae; lateral margins irregular or eroded near where setae ZV4 on adjacent soft cuticle; setae JV1 (30 – 32), JV2 (37 – 42), JV3 (37 – 44), ZV1 (27 – 30), ZV2 (35 – 38), ZV3 (28 – 33), ZV4 (35 – 40), and JV5 the longest (50 – 59) inserted in bluntly angled lateral corners; postanal seta smooth (40 – 48), about twice as long as paranal setae (19 – 25). Soft opisthogastric cuticle with two pairs of setae, including ZV5 aligned behind R6, and one pair of lyrifissures, ivp ( Fig. 5E ).

Gnathosoma — Adult female. Gnathotectum anterior margin broadly truncate, variably with two lateral, short, smooth prongs or with few denticles, sometimes with smaller denticles between lateral prongs ( Fig. 3C ). Cheliceral shaft, excluding basal section, 136 – 148 long, with slender digits ( Figs 3E, F ); dorsal seta blunt (8 – 11); fixed digit with tiny offset subapical tooth and row of 19-24 very fine teeth ( Fig. 3E ), pilus dentilus minute (1 – 2) at level of 4 th apical tooth; movable digit (62 – 72) tridentate. Subcapitulum rows of deutosternal denticles each with numerous (ca 25-40) fine denticles, those of most anterior row slightly coarser (ca 25-30), 2 nd- 5 th rows with ca 35-40 teeth, 6 th and sometimes 7 th rows slightly wider and slightly more denticulate ( Fig. 4D ); subcapitular setae hp1 (30 – 37) slightly shorter than capitular setae pc (36 – 42), hp3 slightly longest (40 – 47), much longer than hp2 (23 – 27). Salivary styli and corniculi as in figure 4C. Palp length (193 – 202); apical margin of palptrochanter without spines anterolaterally; palptrochanter setae dissimilar in length, v1 45 – 63 and v2 34 – 42 (Figs 4E, F).

Adult male. Gnathotectum as in female ( Fig. 5C ). Cheliceral shaft, excluding short basal section, 110 – 120 long ( Fig. 5F ); fixed digit with offset subapical tooth followed by pilus dentilis behind hollow area and row of 10-16 small-sized teeth ( Figs. 5F, G ); movable digit (42 – 45) unidentate; spermatodactyl 40 – 57 long, 6 – 7 wide at base, slightly wider (8) at medial region, extending anteriorly ca 35 beyond apex of digit, with narrowed neck and small head apically ( Figs 5F, H ). Corniculi slightly more widely spaced and arched inwardly than in female, 25 – 30 long, and flanked medially by pair of short (7 – 8) spiculate processes ( Figs 5I , 11B ); internal malae and labrum as in female. Subcapitulum with seven or rarely eight rows of deutosternal denticles formed much as in female; hypostomatic setae hp1 not attenuated (21 – 27), slightly shorter than capitular setae pc (22 – 32), hp3 (30 – 37) slightly longest, hp2 shortest (15 – 20) ( Fig. 5I ). Palpi (length 173 – 188) similar in structure, form of setae as in female; palptrochanter with inner seta longer (38 – 40) than outer seta (20 – 23) but not markedly whip-like ( Fig. 5I ).

Legs — Adult female. Legs I (669 – 715) nearly as long as legs IV (678 – 725), and slightly longer than dorsal shield; other leg lengths (excluding pretarsi): II 519 – 529, III 538 – 545 ( Figs 6 A-E). Leg I pretarsus with biarticulated shaft (38 – 45 to base of claws), claws 15 – 17 long; tarsus (173 – 182) about 1.4-1.5 longer than tibia; other length ratios, femur (137 – 145): genu (110 – 117): tibia (112 – 124) about 1.2: 0.95: 1.0. Legs II-IV with tarsus/tibia length ratio about 2.0-2.2 ( Figs 6C, D ). Chaetotactic formulae of leg segments as given for species-group. Tarsi II-IV with ventroapical process (15 – 17) truncate-spiculate apically ( Figs 13C , 14B ), and with setae (d-1) (25 – 30) shorter than pretarsus to base of claws (33 – 44). Tarsi II-IV with paradactyli nearly symmetrical, weakly developed, anterior element barely extending beyond tip of claw ( Figs 13G , 14B ). Tarsi II ( Fig. 13C ), III with setae (l-1) (44 – 48) shorter than (v-l) (50 – 65); dorsal seta md (77 – 85) longest of tarsal setae, (d-2) barbed, less attenuated (50 – 62). Tarsus IV with setae av-1 (70 – 75) slightly longer than pv-1 (60 – 65), both nearly twice as long as similarly slender (l-1) (38 – 42) ( Fig. 14B ).

Adult male. Legs I slightly thicker than those of female, and longer than dorsal shield; relative lengths similar to those of female, I 690 – 705, II 475 – 525, III 493 – 507, IV longest, 710 – 735. Legs with segment length ratios as in female. Tarsus I with long pretarsus (25 – 35 to base of claws), claws 15 long. Tarsi II-IV with spiculated form of ventroapical process ( Fig. 13D ), relative lengths of dorsoapical setal processes (d-1) (25 – 28) and pretarsal structures as in female; tarsi II-III with setae (v-1) (45 – 55) symmetrically longer than slender (l-1) (33 – 44), increasingly so on III; tarsus IV with av-1 (70 – 75) and pv-1 (55 – 67) asymmetrically longer than (l-1) (32 – 35) ( Fig. 13D ). Legs II with dorsal setae of genu, tibia, basitarsus and (d-2) of telotarsus (16, 23, 26, 27), distinctively shorter than in female and bluntly spine-like ( Figs 12A , 13D ); genu III and tibiae III-IV seta pv and tibia IV seta av dimorphically hooked, blunt ( Fig. 12B ). Length and form of other setae slightly thicker than in female.

Deutonymph. None available to study for comparative purposes.

Protonymph. General description, based on one specimen, without measurements, for speciesgroup perspective. Dorsal idiosoma ( Fig. 7C ) with setae generally nearly aciculate, but with some setae acquiring slightly tricarinate or barbed form as in adult. Podonotal region holotrichous, with 15 pairs of setae (five pairs added to larval complement, including j2, s5 amidst 11 pairs on podonotal shield and r2, r3, r5 along with larval s6 on lateral soft cuticle); j2 inserted in nearly transverse alignment with j1. Opisthonotal region holotrichous, with 15 pairs of setae (five pairs added to larval complement, including J1, Z1, Z2, S2, R1, all on interscutal soft cuticle; pygidial shield expanded so as to include eight pairs of setae, including J3, Z5, S4, S5 (all larval setae).

Ventral idiosoma ( Fig. 7D ) with all setae aciculate, with no postlarval podosomal additions except st5. Sternal poroids iv1, iv2 present, iv3 absent, and larval funicules suppressed. Anal shield oval, with paranal setae similar in length or slightly shorter than postanal seta; rudiments of euanal setae suppressed. Opisthogastric soft cuticle with four or five pairs of setae, with asymmetrical addition of ZV5, which usually deutonymphal; JV5 relatively larger than in larva, and inserted more posteriorly, in transverse alignment with postanal seta.

Gnathosoma — Fixed cheliceral digit with even row of 12-13 teeth; movable digit tridentate. Gnathotectum similar in form to adult. Subcapitulum with four pairs of setae, hypostomatic h1-h3 and capitular pc. Palpus with normal protonymphal complement of setae, including one on trochanter ( Lindquist & Evans 1965); palptarsus with hyaline flap developed beside apotele as in adult.

Legs — Legs I-IV with claws, pretarsi and shape of setae similar to adult female; tarsi II-IV with ventroapical process similar in form, serrated apically, as adult. Legs I, II, III, IV with normal, holotrichous protonymphal chaetotaxy ( Lindquist & Evans 1965), except genu IV with accelerated presence of usually deutonymphal seta pl-1, and femur IV with accelerated alveolar indication of seta v-1 near basal lyriform fissure: coxae 2, 2, 2, 1; trochanters 4, 4, 4, 4; femora 10 (2 2/1 2/2 1), 8 (1 2/1 2/1 1), 5 (1 2/1 1/0 0), 4 (1 2/0 1/0 0); genua 8 (1 2/1 2/1 1), 6 (1 2/0 2/0 1), 6 (1 2/0 2/0 1), 6 (1 2/0 2/0 1); tibiae 8 (1 2/1 2/1 1), 7 (1 1/1 2/1 1), 7 (1 1/1 2/1 1), 7 (1 1/1 2/1 1); tarsi II-IV each with 17 (md added to larval complement). Tarsus IV with seta av-1 distinctively erect, longer and slightly thicker than all other tarsal setae ( Fig. 12G ), in contrast to its form on tarsi II, III of protonymph, and on tarsus IV of adult.

Larva. General description, based on two unborn specimens, without measurements, for species-group perspective. Dorsal idiosoma ( Fig. 7A ) with all setae aciculate. Podonotal shield holotrichous with typical nine pairs of setae j (1, j3-j6, z2, z4, z5, s4); setae s6 on soft cuticle behind posterolateral margin of shield. Opisthonotal region holotrichous with 10 pairs of setae (J2-J5, Z3-Z5, S3-S5); pygidial shield margins mostly indiscernible on specimens at hand, but its surface with typical pair of arcuate lines near insertions of setae J4, and with typical complement of four pairs of setae, including tiny J4, J5 and prominent Z3, Z4. Soft interscutal cuticle with two pairs of mesonotal scutellae and typical six pairs of setae, including moderately long J2, J3, S3, S5, prominent Z5 (in ventrolateral position), and shorter S4.

Ventral idiosoma ( Fig. 7B ) with all setae aciculate. Sternal shield outline not distinguishable; setae st1-st3 similarly short, st4, st5 absent, but the typical pair of subcutaneous structures (‘funicules’ sensu Athias-Henriot 1971a ) present posteromediad bases of legs III. Anal shield margins indistinguishable; anal valves with rudimentary pair of euanal setae; paranal setae slightly longer than postanal seta. Opisthogastric soft cuticle with typical four pairs of similarly short setae (JV1, JV2, JV5, ZV2).

Gnathosoma — Fixed cheliceral digit with even row of 10-11 teeth; movable digit bidentate. Gnathotectum triramous, branches shorter than in adult. Subcapitulum with two pairs of hypostomatic setae, h1 longer than h2. Palpus with normal larval complement of setae ( Lindquist & Evans 1965); palptarsus with hyaline flap not evident beside apotele.

Legs — Legs I-III with claws, pretarsi and shape of setae similar to adult female; tarsi II, III with ventroapical process similar in form, serrated apically, as adult, and with setae d- (1) more strongly developed, slightly longer than pretarsi to base of claws. Legs I, II, III with normal, holotrichous larval chaetotaxy ( Lindquist & Evans 1965): trochanter 2, 2, 2; femora 10, 7, 5; genua 8, 6, 6; tibia 8, 7, 7; tarsi II, III each with 16.

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 leaves, successional plots, coll. ALAS. PARATYPES: 5 adult females, 5 adult males, 1 protonymph, with same data as holotype ; 3 adult females (2 gravid with larva), 6 adult males, 12 June 1997, ex coexistent adults of Cephaloleia belti Baly and C. ornatrix Donckier from Heliconia leaves, coll. ALAS; 1 adult female (CRI 002: 739027), 8 July 1997, ex adult Chelobasis perplexa Baly , no host plant data, coll. M. Paniagua; 3 adult females, 1 adult male, June 1997, ex adult Cephaloleia ornatrix , no host plant data, coll. D. Johnson.

Host identifications — The identities of the associated beetles given above are in accord with current molecular studies, which indicate that one haplotype Chelobasis of perplexa sensu stricto and records of Cephololeia belti and C. ornatrix on Heliconia pogonantha 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 a Latinized adjectival combination of ‘serra’, meaning saw or toothed like a saw, and ‘pes’, meaning foot, and refers to the unusual apically serrated form of the ventral apical tarsal process of legs II to IV.

Remarks — One female is asymmetrical in having seta r6 on edge of dorsal shield on one side, rather than on soft cuticle. As noted under morphological remarks following description of the cassidini species-group, the rudimentary presence of seta av-1 on femur IV and full presence of seta pl-1 on genu IV are ontogenetic accelerations of setae that are typically first expressed in the deutonymph ( Evans 1963).

Although far from definite, collection records of Lasioseius serripes indicate a frequent association with Cephaloleia ornatrix , which perhaps is the preferred companion. Tentatively, subject to further studies, we conclude that, at La Selva, Lasioseius serripes is associated regularly with the host specialist C. ornatrix and to some extent with a form of Chelobasis and the host generalist C. belti on H. pogonantha .

Figures

Figure 3 Lasioseius serripes n. sp., adult female: A – Idiosoma, dorsal view; B – Detail of denoted dorsal setae; C – Gnathotectum; D – Spermathecal structures; E – Cheliceral digits, paraxial view; F – Cheliceral digits, antiaxial view.

Figure 4 Lasioseius serripes n. sp., adult female: A – Idiosoma, ventral view; B – Detail of paralabrum; C – Detail of corniculus and salivary stylus; D – Subcapitulum; E – Palp, dorsal view; F – Detail of palptarsus; G – Detail of hyaline anterolateral flap of palptarsus.

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 6 Lasioseius serripes n. sp., adult female, right legs I-IV (excluding tarsus): A – Leg I, dorsal view; B – Leg I coxa, ventral view; C – Leg II, posterodorsal view (coxa ventral view); D – Leg III, anterodorsal view (coxa ventral view); E – Leg IV, dorsal view (coxa ventral view). (Solid black setae indicate dorsal setae on segments).

Figure 7 Lasioseius serripes n. sp.: A – Larva, idiosoma, dorsal view; B – Larva, idiosoma, ventral view; C – Protonymph, idiosoma, dorsal view; D – Protonymph, idiosoma, 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).