Lasioseius latinoamericanus, De, Jeferson L., Lindquist, Evert E. & De, Gilberto J., 2009

De, Jeferson L., Lindquist, Evert E. & De, Gilberto J., 2009, Edaphic ascid mites (Acari: Mesostigmata: Ascidae) from the state of São Paulo, Brazil, with description of five new species, Zootaxa 2024, pp. 1-32 : 10-14

Lasioseius latinoamericanus sp. nov.

( Figs 18–27 )

Diagnosis: Adults of this species are closely similar to those of Lasioseius floridensis Berlese 1916 , L. queenslandicus ( Womersley 1956) and L. sugawarai Ehara 1964 , all of whose females are characterized by the dorsal shield having 21 pairs of setae, including r4 but excluding r5, with post-humeral seta r4 short and simple, similar to r2, and not more than half as long as tricarinate seta s4 neighboring it medially; most dorsal shield setae tricarinate and moderately long, many nearly as long as longitudinal intervals between their bases; first pair of sternal setae on weak pre-sternal sclerotization just before anterior margin of sternal shield; sternal shield with an anteromedial patch of reticula; tarsus II with one midlateral seta, pl -2, elongated, reaching nearly to base of pretarsus. The adults of each of these species are distinctive from the others in the forms of the female spermathecal apparatus and, in some cases, of the male spermatodactyl. In female L. latinoamericanus n. sp., a moderately long major duct leads from the solenostome to a densely sclerotized region (the embolus) from which arise a slender funnel-shaped calyx and a fine minor duct of undetermined length and undiscerned terminus ( Fig. 20 ); the spermatodactyl is only slightly longer than the male cheliceral movable digit, untapered, and bluntly arrowhead-shaped with a dorsal hook subapically ( Fig. 27 ), similar to that of L. queenslandicus ( Walter & Lindquist 1997, Figs 11, 12 ). In female L. floridensis a short major duct leads to a strongly sclerotized, shallowly cup-shaped calyx from which a long, convoluted minor duct arises that is divided for a short interval before its slightly thickened, truncate terminus ( Fig. 16 ); the spermatodactyl is ca. 1.5 as long as the male movable cheliceral digit, tapered and slightly sinuate distally ( Fig. 17 ). In female L. queenslandicus the sperm access system is bifurcate, with a tubular, weakly sclerotized calyx and a thick minor duct that arises near the solenostome and terminates in an enlarged flower-like structure ( Walter & Lindquist 1997, Figs 5, 6 ); as noted above, the male spermatodactyl is similar to that of L. latinoamericanus . In female L. sugawarai the apparatus is small, very weakly sclerotized, bulbous, without a minor duct, and seemingly vestigial ( Ehara 1964, fig. 46); the male is not known for this species.

Adult female: Dorsal idiosoma ( Fig. 18 ): Dorsal shield 402–422 µm long, 205–212 µm wide at midlength level of setae s6, reticulate over entire surface, with sparse puncta posteriorly between setae Z4-J5, but without punctate areas on either side between setae J1-J3 and Z1-Z3; with 21 pairs of setae (j1-j6, z1-z6, s1- s6, r2-r4) on anterior region and 15 pairs of setae (J1-J5, Z1-Z5, S1-S5) on posterior region. Most setae on dorsal shield moderately long (25–40 µm), Z4 and Z5 subequally longest (45–50 µm), j1, J3, Z4, s4-s6 and S1-S4 nearly (0.7–0.9) to subequally as long as distance to insertions of next seta in series; z1, s2, r2, r4 and J5 short (13–18 µm but s2 only 8–9 µm), simple, except J5 slightly barbed basally; r4 (17–18 µm) half as long as tricarinate seta s4 (34–35 µm) neighboring it medially, s1 (23–24 µm) stouter than and over twice as long as s2 (8–9 µm); other dorsal shield setae stout, tricarinate, and Z3-Z5, S4 and S5 also barbed. Lateral soft cuticle with 8 pairs of marginal setae (r5-r6, R1-R6) and one pair of submarginal setae below level of R1-R2, these setae similarly short (19-25 µm), simple, except r5 slightly tricarinate and larger (28–29 µm), and UR shorter (10–12 µm).

Ve n tr a l idiosoma ( Fig. 19 ): Tritosternum with laciniae free for ca. 52–54 µm of their total length (70–75 µm). Pre-sternal area lineate, microtuberculate, and containing first pair of sternal setae. Sternal shield finely puncate over most of surface, lineate along lateral margins, with anteromedian patch of reticula, second and third pairs of sternal setae and two pairs of poroids. Metasternal plates suboval to subquadrangular, with 4th pair of sternal setae and third pair of poroids. Endopodal strips normally formed alongside coxae III–IV. Genital shield nearly truncated posteriorly, scarcely widened behind genital setae, densely punctate; paragenital pores in soft cuticle posterior to level of genital setae. Post-genital strip divided into 4 well defined platelets. Metapodal plates divided into smaller narrow element (ca. 10 µm long) and larger oval or subtriangular element (15–16 µm long, 8–10 µm wide). Ventri-anal shield wider (160–174 µm) than long (128–138 µm), with transverse lineation connected by few diagonal lines that are more numerous in anal region, and sparsely punctate in anal region; shield with usually 4 pairs of ventral setae (JV1-JV3, ZV2, and rarely asymmetrically one of ZV3) plus 3 circum-anal setae of which para - anals shorter (20–23 µm) than postanal seta (30–32 µm), these setae simple, similar in length; anal opening not enlarged (length 25 µm). Ventral soft cuticle with 7 pairs of setae (ZV1, ZV3-ZV5, JV4, JV5, and a pair of submarginal UR -setae laterad ZV4) around ventri-anal shield; most posterior two pairs (JV5, ZV5) larger (35–37, 28–30 µm, respectively), weakly tricarinate (ZV5 not tricarinate in some specimens). Exopodal plate a continuous strip alongside coxae II–IV.

Peritrematal shield and peritreme ( Figs 18–19 ): Peritrematal shields fused to dorsal shield at level between setae z1 and s1 and broadly fused to exopodal shields at level of coxae IV; peritremes extending anteriorly nearly to bases of setae j1.

Spermathecal apparatus ( Fig. 20 ): with major duct leading to small, densely sclerotized region (embolus) from which minor duct and slender funnel-like calyx arise (length ca. 35 µm, width 7–9 µm); extent of minor duct indiscernible in specimens at hand.

Gnathosoma ( Figs 21–23 ): Anterior margin of tectum with 3 denticulate prongs. Fixed cheliceral digit with short pilus dentilis, offset subapical tooth, and row of 12–14 evenly sized teeth; movable digit (length 40 µm) tridentate; lateral hyaline rim along paraxial face of digit serrated at level of base of movable digit.

Deutosternum with 7 connected rows of denticles; anterior 5 rows each with 9–12 denticles; 6th and 7th rows slightly wider, with 14–20 and 13–16 denticles, respectively. Hypostomatic setae h1 not elongated, nearly as long as h2 (30–34 µm); internal mala slightly longer than corniculus, with lateral margin finely fringed. Palptrochanter with internal seta subequally as long as external seta (ca. 25 µm).

Legs ( Fig. 24 ): Legs I and IV similar in length (362–375 µm and 382–392 µm, respectively), and nearly as long as dorsal shield; pretarsus of leg I slender (20–22 µm), pretarsi of legs II–III similar in length (15–17 µm), slightly shorter than pretarsus IV (20 µm); tarsi II–IV with apical setal processes (9–14 µm) about half as long as pretarsi; pretarsi II–IV with paradactyli projecting to apices of claws. Genua and tibiae of legs I-II-III- IV with 13-11-9-9 and 13-10-8-10 setae, respectively, without deficiencies. Tarsus II with seta pl -2 slender, elongated (38-40 µm) but short of reaching base of pretarsus; tarsus III without elongated setae. Tarsus IV (127–130 µm) ca. 1.4 as long as tarsi II (95 µm) and III (88 µm); leg IV setae pd -3 on basitarsus and pd -2, mv on telotarsus longer (40–43) than others, but these not equaling length of tibia IV (48–50 µm). All leg setae smooth.

Adult male. Dorsal idiosoma: Dorsal shield 302–315 µm long, 168–171 µm wide at midlength, ornamented as on female; with 23 pairs of setae (j1-j6, z1-z6, s1-s6, r2-r6) on anterior region and 15 pairs of setae (J1-J5, Z1-Z5, S1-S5) on posterior region. Length and shape of setae similar to female, except that Z2 and Z3 are also at least as long as distance to insertions of next seta in series. Soft cuticle with 6 pairs of marginal setae (R1-R6), their relative lengths as in female; submarginal setae absent.

Ven tra l idiosoma ( Fig. 25 ): Tritosternum as in female. Pre-sternal area sparsely lineate and microtuberculate. Sternogenital shield lightly punctate over most of surface, lineate along lateral margins, with 5 pairs of setae and 3 pairs of poroids. Ventri-anal shield (115–120 µm long, 155–158 µm wide) covering most of opisthogaster, incorporating metapodal plates but not fused to peritrematal shield, ornamented as in female, with 6 pairs of ventral setae (JV1-JV3, JV5, ZV1, ZV2) plus 3 circum-anal setae. One pair of setae (R6) on ventral soft cuticle beside ventri-anal shield; most posterior pair (JV5) slightly barbed, weakly tricarinate, larger (22–23 µm) than other, simple opisthogastric setae; JV4, ZV3, ZV4, ZV5 absent.

Peritrematal shield and peritreme ( Fig. 25 ): Peritrematal shields uniting with dorsal shield at level of setae r3; peritremes as in female.

Gnathosoma ( Figs 26–27 ): Anterior margin of tectum truncate and variably with 2 or 3 short denticulate prongs. Fixed cheliceral digit with short pilus dentilis, offset subapical tooth, and row of ca. 9 teeth; movable digit (length 25–27 µm) with one tooth; spermatodactyl stout, shaft 30 µm long, slightly sinuous, extending 15–18 µm beyond tip of movable digit, ending in knob-like process with dorsal subapical spur. Subcapitular structures as in female, except that corniculi more slender and widely separated, 6th and 7th rows of deutosternal denticles more densely denticulate, with ca. 25 and 20 denticles, respectively.

Legs: Legs I and IV similar in length (300–310 µm and 310–315 µm, respectively) and subequal in length to dorsal shield. Setation and relative lengths and form of setae and other structures on legs I–IV as in female, with no sexually dimorphic thickened structures.

Material examined. Holotype female, paratype male, 5 paratype females and 5 paratype males, 5.iv.1999, from litter of a patch of rubber tree plantation, ESALQ-USP, Piracicaba, State of São Paulo, col. J.L. de C. Mineiro, deposited at ESALQ / USP. One paratype female, 9.x.1998, from the same habitat as holotype, col. J.L. de C. Mineiro, deposited at ESALQ-USP. One paratype female, 21.xii.1998, from the same habitat as holotype, col. J.L. de C. Mineiro, deposited at ESALQ-USP. Additional paratypes, 2 females and 1 male, COSTA RICA, Prov. Heredia, La Selva, elev. 50–150 m, collected from pan traps set in lowland tropical rainforest litter, 15 June 1998 and 13 August 1998, by ALAS parataxonomist team. Two paratype females and one paratype male deposited at CNCI; one paratype female and one paratype male deposited at INBio, Costa Rica.

Remarks: The description of L. latinoamericanus n. sp. as distinct from other species noted in the diagnosis, especially concerning details of the female spermathecal apparatus, is based on the examination and notes by one of us (EEL, unpublished) of the type material of those species. L. latinoamericanus is a member of a group of species that we call the floridensis -group, which may be characterized by the shared suite of dorsal idiosomal, sternal, ventri-anal and leg attributes mostly noted for species in the diagnosis. Because of inadequate description of most species of this group and a lack of subsequent studies of their type material, there remains considerable confusion about the distinctiveness of some of its members, with some synonymy expected among named entities.

Etymology: The name latinoamericanus refers to the region in the American continent (Latin America) where the types of this new species were collected.

Figures

FIGURES 16 – 27. Lasioseius spp.: L. floridensis Berlese. Female spermatheca (16) and male chelicera (17). L. latinoamericanus n. sp. Adult female, dorsal idiosoma (18), ventral idiosoma (19), spermathecal apparatus (20), tectum (21), chelicera (22), ventral gnathosoma (23) and tarsus IV (24, one paradactyl not visible). Adult male, ventral idiosoma (25), tectum (26) and spermatodactyl (27).

FIGURES 11 – 15. Gamasellodes magniventris n. sp. Adult female, dorsal idiosoma (11), ventral idiosoma (12), tectum

FIGURES 1 – 10. Cheiroseius neophalangioides n. sp. Adult female, dorsal idiosoma (1), ventral idiosoma (2), spermathecal apparatus (3), tectum (4), chelicera (5), ventral gnathosoma (6), pretarsus III (7) and tibia and tarsus IV (8). Adult male, ventral idiosoma (9) and spermatodactyl (10).