Gaeolaelaps cerrii, Marticorena & Moreira & Moraes, 2020

Marticorena, Jorge L. M., Moreira, Grazielle Furtado & Moraes, Gilberto José De, 2020, Mites of the genus Gaeolaelaps (Acari: Laelapidae) from southern Brazil, with description of two new species, Zootaxa 4772 (2), pp. 333-348 : 338-343

Gaeolaelaps cerrii sp. nov.

( Figures 14–26 )

Diagnosis (female). Dorsal shield with smooth podonotal and reticulate ophistonotal regions, suboval, with 37 pairs (setae z 3 and J 2 missing) of smooth and pointed setae, except J 4 and J 5 and occasionally Z 5 (in two of ten specimens examined), slightly barbed medially; gland pores gd2 and gd6 absent. Sternal shield smooth; posterior margin blunt to slightly convex. Genital shield tongue-like and with scant reticulation. Anal shield subtriangular, reticulate, without marginal pores. Opisthogaster with eight pairs of setae (Jv 1– Jv 5, Zv 1, Zv 2 and Zv 4). Peritreme extending anteriorly to level between z 1 and s 1, with anterior half visible at dorsal view. Epistome convex, covered with subparallel lines; anterior margin denticulate. Deustosternum with six denticulate rows, each with 10–12 denticles. Fixed and movable cheliceral digits with respectively seven and two teeth.

Adult female. (n= 8)

Dorsal idiosoma ( Figs 14, 15 ). Podonotal region of dorsal shield smooth and opisthonotal region reticulate and posteriorly rounded; 408 (395–432) long and 210 (198–220) wide; with 37 pairs of pointed setae, including two pairs of extra opisthonotal setae (j 1– j 6, z 1,z2, z 4– z 6, s 1– s 6, r 2– r 5, J 1, J 3– J 5, Px 2, Px 3, Z 1– Z 5, S 1– S 5; setae z 3 and J 2 absent), all of which smooth, except J 4 and J 5 and occasionally Z 5, slightly barbed; with 15 pairs of lyrifissures and four pairs of pores (gd2 and gd6 absent). Unsclerotised cuticle laterad of dorsal shield with a single pair of setae ( R 1 ). Setal length: j 1 25 (23–28), j 2 25 (24–30), j 3 32 (28–35), j 4 30 (27–33), j 5 26 (22–29), j 6 23 (22–25), z 1 27 (22–30), z 2 32 (28–36), z 4 35 (35–36), z 5 30 (28–30), z 6 29 (23–31), s 1 23 (19–25), s 2 25 (23–26), s 3 32 (30–33), s 4 31 (30–35), s 5 28 (25–31), s 6 29 (26–32), r 2 31 (28–34), r 3 30 (28–32), r 4 26 (24–29), r 5 29 (26–30), J 1 23 (21–25), J 3 21 (20–23), J 4 32 (30–34), J 5 32 (30–35), Px 2 21 (20–24), Px3 25 (23–26), Z 1 34 (32–36), Z 2 27 (25–28), Z3 31 (30–35), Z 4 40 (38–40), Z 5 50 (47–53), S 1 26 (22–30), S 2 25 (22–27), S 3 26 (22–28), S 4 30 (29–33), S 5 37 (34–40), R 1 17 (15–20).

Ventral idiosoma ( Fig. 16 ). Base of tritosternum 24 (22–25) long and 12 (11–13) wide basally; laciniae 74 (72–76), separated by about 95% of their total length. With a pair of punctuate and transversely striate presternal platelets, fused with each other. Sternal shield smooth, with three pairs of setae (st 1– st 3) and two pairs of lyrifissures (iv 1, iv 2); posterior margin slightly convex to truncate; length 102 (100–106), width 93 (90–99). Distances between setae st 1– st 1 63 (60–65), st 2– st 2 84 (80–89), st 3– st 3 84 (82–85). Seta st 4 and lyrifissures iv 3 on unsclerotised cuticle. Anterior region of endopodal plate fused with sternal shield; region behind sternal shield represented by a triradiate arched platelet, with short and sharp anterior and lateral projections, and elongate and blunt posterior projection. Exopodal plate fragmented, subtriangular between coxae II–III and III–IV, and elongate and arched near coxae II–IV. Genital shield tongue-like and with scant reticulation, 148 (157–168) long, 75 (68–81) wide; distance st 5– st 5 70 (66–72). Genital lyrifissures (iv 5) on unsclerotised cuticle posterolaterad of st 5; with a pair of slender paragenital platelets posteriad of iv 5; with a pair of transversely elongate platelets next to Zv 1. With two pairs of metapodal platelets, one subtriangular to ellipsoidal and other diagonally to transversely elongate. Anal shield subtriangular, reticulate; cribrum with 2–3 rows of spines; glands gv 3 indistinguishable. Opisthogaster with eight pairs of simple setae (Jv 1– Jv 5, Zv 1, Zv 2 and Zv 4) and five pairs of lyrifissures. Setal lengths: st 1 27 (25–30), st 2 29 (23–31), st 3 28 (25–31), st 4 24 (20–26), st 5 21 (19–25), Jv 1 20 (19–21), Jv 2 22 (19–24), Jv 3 23 (22–26), Jv 4 23 (20–26), Jv 5 34 (30–38), Zv 1 19 (16–20), Zv 2 23 (20–25), Zv 4 23 (21–25), para-anal 24 (21–25), postanal 27 (23–30). All setae smooth and pointed.

Peritreme and peritrematic plate ( Figs 14, 16 ). Peritreme 198 (191–203) long, extending anteriorly to level between z 1 and s 1; peritrematic plate fused to dorsal shield near z 1, with a lyrifissure (anterior) and a pore between coxae II–III of each side and a pair of lyrifissures and a pore behind each stigma.

Gnathosoma ( Figs 17–21 ). Anterior region of epistome convex; anterior margin denticulate and followed by subparallel radiating lines. Chelicera with dorsal lyrifissure distinct; anti-axial lyrifissure indistinguishable; dorsal seta stout. Fixed cheliceral digit 43 (41–45) long, with seven teeth and a short setiform pilus dentilis; movable digit 59 (55–60), with two teeth; each digit with basal tooth distinctly larger than others. Labrum extending forward to a level slightly beyond tip of corniculus. Deustosternal groove with six denticulate rows, each with 10–12 denticles; with three smooth transverse lines laterad of deutosternal groove. Corniculi parallel to each other, 37 (35–40) long and 12 (11–14) wide, reaching distal end of palp trochanter; h 3 posteromediad of h 2. Internal malae subtriangular, fimbriate. Setal lengths: h 1 25 (22–30), h 2 14 (11–16), h 3 29 (26–30), pc 18 (16–20). Palp 156 (154–160) long; with usual numbers of setae for the Mesostigmata ( Evans, 1964) ; all setae smooth; seta al 1 of genu 10 (9 –10), stout, bacillate to thorn-like; seta al 2 genu 16 (16 –17) and al 1 of femur 20 (18 –21), spine-like. Palp-tarsal claw with two-tines of very distinct lengths.

Spermathecal apparatus ( Fig. 22 ). Tubulus about 1 µ in diameter; rami lightly sclerotised, enlarging about uniformly toward sacculus, apparently without constriction near attachment with sacculus; about 10 µ away from each other at attachment to sacculus; sperm duct elongate, widening progressively toward attachment.

Legs ( Figs 23–26 ). Length (not including ambulacra): I, 384 (365–400); II, 279 (268–290); III, 243 (230–250); IV, 353 (320–375). Chaetotaxy (coxa–tibia): I, 0 0/2 0/0 0; 1 0/1 1/2 1; 2 2/1 3/3 2; 2 3/2 3/1 2; 2 3/2 3/1 2; II 0 0/1 0/1 0; 1 0/1 0/2 1; 2 3/1 2/2 1; 2 3/1 2/1 2; 2 2/1 2/1 2; III 0 0/1 0/1 0; 1 1/1 0/1 1; 1 2/1 1/0 1; 2 2/1 2/1 1; 2 1/1 2/1 1; IV 0 0/1 0/0 0; 1 1/1 0/1 1; 1 2/1 1/0 1; 2 2/1 3/0 1; 2 1/1 3/1 2; tarsi II–IV with 18 setae each. Setae pd 1 43 (41–46) of femur II, pd 2 33 (28–35) of genu II, ad 1 of femur IV 50 (46–55) and pd 2 of tarsus IV 74 (70–78) distinctly longer (at least 1.3 times) than other setae of the same respective segments. With the following setae stouter than other setae of same segments: leg II: av of femur; mv, pl 2, av 2, pv 2, al 1, pl 1, av 1 and pv 1 of tarsus; leg III: most tarsal setae, with clear exception of ad 3, pd 3 and pl 3; leg IV: pv of femur, av of genu; av of tibia; pd 3, mv, pl 2, av 2, pv 2, mv, av 1 and pv 1of tarsus.

Male ( Figures 27–33 ). (n= 3)

Dorsal idiosoma ( Fig. 27 ). Ornamentation and shape of dorsal shield as in female; 316 (310–322) long and 186 (180–190) of maximum width; with 36 pairs of pointed setae, differing from female by lacking S 1; all setae smooth and pointed, except J 4, J 5 and Z 5, slightly barbed; 13 pairs of lyrifissures and two pairs of pores. Setal lengths: j 1 17 (17–18), j 2 21 (20–22), j 3 28 (25–30), j 4 24 (22–26), j 5 19 (17–20), j 6 18 (17–19), z 1 17 (13–20), z 2 26 (25–28), z 4 28 (26–30), z 5 23 (22–23), z 6 20 (19–21), s 1 20 (20–21), s 2 21 (20–23), s 3 24 (22–25), s 4 22 (20–24), s 5 24 (22–25), s 6 20 (17–24), r 2 24 (20–26), r 3 23 (21–25), r 4 21 (20–22), r 5 22 (20–24), J 1 18 (17–21), J 3 17 (16–18), J 4 24 (22–25), J 5 24 (22–25), Z 1 24 (22–26), Z 2 20 (20–21), Z 3 23 (21–25), Z 4 30 (28–31), Z 5 34 (31–38), S 2 20 (18–21), S 3 19 (19–20), S 4 22 (20–24), S 5 24 (22–25), Px 2 17 (16–17), Px 3 20 (18–21), R 1 14 (13–15).

Ventral idiosoma ( Fig. 28 ). Base of tritosternum 15 (14–15) long and 8 (8–9) wide basally; laciniae 56 (54– 58), separated by about 95% of their total; line separating base from laciniae sometimes not distinguishable. With a pair of presternal platelets, punctuate and transversely striate, separate from each other. Holoventral shield reticulate behind leg IV, smooth elsewhere, with eight pairs of setae (st 1– st 5, Jv 1, Jv 2 and Zv 2) in addition to circumanal setae and five pairs of lyrifissures; Jv 4 and Jv 5 on unsclerotised cuticle; distance between st 1– st 5 141 (135–146), st 1– st 1 51 (50–52), st 2– st 2 67 (66–68), st 3– st 3 64 (62–65), st 4– st 4 53 (52–55), st 5– st 5 45 (44–46). Exopodal plate fragmented; subtriangular between coxae I–II and III–IV, elongate and arched near coxae II–IV. Setal lengths: st 1 24 (23–25), st 2 24 (22–25), st 3 22 (20–24), st 4 20 (20–21), st 5 21 (19–22), Jv 1 21 (20–22), Jv 2 21 (20–21), Jv 4 18 (15–20), Jv 5 21 (18–24), Zv 2 22 (22–23), para-anal 18 (16–19), postanal 14 (13–15).

Peritreme and peritrematic plate ( Figs 27, 28 ). Peritreme 172 (165–180) long, extending anteriorly slightly beyond base of s 1; peritrematic plate apparently fused with dorsal shield near base of z 1, with a lyrifissure (anterior) and a pore in region between coxae II–III; a pair of lyrifissures and a pore behind stigma.

Gnathosoma ( Figs 29–32 ). Anterior region of epistome convex; anterior margin denticulate and followed by subparallel radiating lines. Chelicera with dorsal lyrifissure distinct; anti-axial lyrifissure and dorsal setae distinct. Fixed cheliceral digit 22 (20–24) long, with 6 teeth in addition to apical tooth and a short setiform pilus dentilis; movable digit 34 (33–34) long, with a single relatively large tooth. Spermadactyl L-like, of uniform thickness along most of its extension, enlarged at angle of distally recurved section; distinctly longer than movable digit. Labrum reaching slightly beyond tip of corniculus. Deustosternal groove with six denticulate lines each with 8–12 denticles; with three transverse lines laterad of deutosternal groove. Corniculi parallel to each other, 20 (17–22) long and 7 (6–9) wide basally, reaching basal region of palp femur; h 3 in transverse line with h 2. Setal lengths: h 1 20 (19–21), h 2 11 (11–12), h 3 22 (20–23), pc 14 (13–16). Palp 117 (108–124) long, similar to female; al 1 of genu almost in transverse line with al 2, the first 9 (8–10), stout, bacillate, the second 15 (14–16), spine-like; seta al 1 of femur 17 (16–18), spine-like. Palp-tarsal claw with two tines of very distinct lengths.

Legs ( Fig. 33 ). Length (not including ambulacra): I, 320 (312–332); II, 233 (230–235); III, 195 (185–204); IV, 281 (270–294). Chaetotaxy same as in female. With the following setae stouter than other setae of same segments: leg II: pl of femur, av and pv of tibia, mv, av 2, pv 2, al 1, pl 1, av 1, pv 1 of tarsus; leg III: pd 1 of femur, ad 1, av 2, md, mv, pl 2 and pv 2 of tarsus; leg IV ( Fig. 33 ): pd 2 of femur, av of genu, av and pv of tibia, av 1, av 2, mv, pd 2, pv 1 and pv 2 of tarsus.

Type specimens. Holotype female collected at Valparaíso from soil (0–5 cm deep) of grassland. Two paratype females and one paratype male collected at the same locality, from litter, and one paratype female from soil (0–5 cm deep), both of a Saccharum officinarus plantation. Three paratype females collected at the same locality, from grassland soil (0–5 cm deep). One paratype female and two paratype males collected at Jataí, from litter of a grassland. All collected between 8 and 16/XII/2014.

Remarks. The species here described seems most similar to Gaeolaelaps vanpletzeni ( Aswegen & Loots, 1970) , which differs from it mostly by the different pattern of reticulation of the dorsal shield (with reticles of about uniform shape and extending anterolaterally to level of r 4); additionaly, according to Strong & Halliday (1994), G. vanpletzeni has a spine-like seta on trochanter IV, which is absent in the new species. It is also similar to Gaeolaelaps iranicus Kavianpour & Nemati (in Kavianpour et al., 2013), apparently sharing with it the same characteristics of the peritreme and peritrematic plate and the same chaetotaxy of the dorsum of the idiosoma (except that seta identified as Px 2 and R 1 in this publication were interpreted respectively as J 2 and r 6 in that publication). That species differs from the new species here described by having different reticulation pattern on dorsal shield (reticles of about uniform shape) and by missing S 1. Gaeolaelaps praesternalis (Willman, 1949) and Gaeolaelaps nolli ( Karg, 1962) are also similar to the new species, differing by having J 2 (as well as Px 2) and z 3. In addition, G. praesternalis has shorter peritreme (reaching only middle of coxa II) and sternal shield reticulate. Gaeolaelaps kargi ( Costa, 1968) and Gaeolaelaps lenis Vatankhah & Nemati, 2016 differ by having J 2 (as well as Px 2) and by having reticles of dorsal shield of about uniform shape; also, G. lenis has shorter peritreme, reaching only slightly beyond r 2. Gaeolaelaps invictianus Walter & Moser, 2010 differs from the new species by lacking post-anal seta in adult males and females, by having reticulate female sternal shield and by having posteriorly eroded male holoventral shield, separating its posterior end (containing the anal opening) from the remaining section. As in the species here described, other Gaeolaelaps species also lack z 3 and one or both Px setae (as G. fishtowni and some specimens of G. queenslandicus ), but these are very different from the new species here described, by the having dorsal shield tapered posteriorly and several R setae on the unsclerotised cuticle.

Etymology. This species is described as a posthumous homage to Carlos Clementi Cerri, eminent Professor of “Centro de Energia Nuclear na Agricultura, Universidade de São Paulo ”, Piracicaba, Brazil, who greatly contributed to the conduction of this work.

Figures

FIGURES 14–22. Gaeolaelaps cerrii n.sp.; Female: 14, dorsal view of idiosoma; 15, setae; 16, ventral view of idiosoma; 17, epistome; 18, gnathosoma; 19, anti-axial view of chelicera; 20, labrum; 21, pedipalp; 22, spermathecal apparatus.

FIGURES 23–26. Gaeolaelaps cerrii n.sp.; Female: 23, leg I; 24, leg II; 25, leg III; 26, leg IV.

FIGURES 27–33. Gaeolaelaps cerrii n.sp.; Male: 27, dorsal view of idiosoma; 28, ventral view of idiosoma; 29, epistome; 30, gnathosoma; 31, anti-axial view of chelicera; 32, pedipalp; 33, leg IV.