Gaeolaelaps setillus, Joharchi & Khaustov & Ermilov, 2019

Joharchi, Omid, Khaustov, Alexander A. & Ermilov, Sergey G., 2019, Two new species of Gaeolaelaps Evans & Till (Acari: Laelapidae) from Sri Lanka, Zootaxa 4615 (3), pp. 563-576 : 569-573

publication ID	https://doi.org/ 10.11646/zootaxa.4615.3.9
publication LSID	lsid:zoobank.org:pub:FEDBF302-2E13-488E-B03D-7D195812FD22
persistent identifier	https://treatment.plazi.org/id/9C63D231-FF98-FFB3-0693-FB95FB5840C9
treatment provided by	Plazi
scientific name	Gaeolaelaps setillus
status	sp. nov.

Treatment

Gaeolaelaps setillus sp. nov.

( Figures 18–34 View FIGURES 18–22 View FIGURES 23–30 View FIGURE 31–34 )

Type material examined: Holotype, female, Sri Lanka, Sabaragamuwa Province, Polgampola , 06°27’ N, 080°12’ E, alt. 42 m, 24 January 2019, O. Joharchi, S.G. Ermilov & A.A. Khaustov coll., from forest soil-litter near the Thambadola Ella waterfall (in TSUMZ) GoogleMaps . Paratypes, three females, same data as holotype (one in TSUMZ, two in ZISP) GoogleMaps .

Diagnosis (female). Dorsal shield with weak reticulation, more distinct in opisthonotal and lateral regions, bearing 38 pairs of setae, 22 pairs of podonotal setae and 16 pairs of opisthonotal setae, S 5 in soft cuticle posterior to shield. All dorsal setae reduced (8–13 long) except j1, S5, Z5. Surface of sternal shield finely reticulated; bearing three pairs of smooth pointed setae, ratio of shield length/width (at broadest level) 0.9. Genital shield ratio of length/width (at broadest level) 1.7, surface without any distinct reticulation, almost≃completely smooth. Anal shield ratio of length/width (at broadest ≃ level) 0.85, cribrum small. Peritreme long, extending to posterior of coxa I, post-stigmatal section of peritrematal shield elongated ≃, slender and ensiform, its tip extending at mid-level of coxa IV. Palp tarsal claw three-tined, fixed digit of chelicera with three teeth, seta ad on trochanter of leg I lanceolate.

Description. Female (n = 4)

Dorsal idiosoma ( Figs 18 View FIGURES 18–22 , 23 View FIGURES 23–30 ). Idiosoma length 318–322, width 182–188, oval-shaped. Dorsal shield 307– 311 long, 182–188 wide at r3 level, covering most of dorsal idiosoma, 153–160 wide at level of S1; with weak reticulation, more distinct in opisthonotal and lateral regions, progressively tapering after r3, subparallel from r4 to level of S4, rounded posteriorly, with narrow strip of unsclerotised integument visible from r3. Shield with 38 pairs of very short setae, 22 pairs of podonotal setae on shield (j1–6; z1–6; s1–6; r2–5) and 16 pairs of opisthonotal setae on shield (J1–5; Z1–5; S1–4; and two pairs of Zx), S 5 in soft cuticle posterior to shield, one supernumerary seta Jx present between J -series, all dorsal setae short (8–13 long), smooth and uniform in thickness except j1, S5, Z5 (18–23), z1 (3–6). Shield with about 15 pairs of discernible pore-like structures, six on podonotum (id1, id2, id4, id5, id6, gd5) and nine on opisthonotum (is1, idm3–5, idl2, idl4, idx, gd8, gd9), others indistinct, see Figures 18 View FIGURES 18–22 and 23 View FIGURES 23–30 .

Ventral idiosoma ( Figs 19 View FIGURES 18–22 and 24–25 View FIGURES 23–30 ). Tritosternum with paired pilose laciniae (43–47), fused basally (2–4), columnar base 13–15 9–11 wide, presternal area lightly sclerotised, with a few transverse curved lines. Sternal shield (length 82–86) narrowest between coxae II (70–75), widest between coxae II-III (93–96), with straight anterior and slightly concave posterior margin, bearing three pairs of smooth pointed and subequal setae (st 1 20–22, st 2 20–22, st 3 19–21), setae never reaching base of next posterior setae, and two pairs of poroids (iv1 and iv2 slitlike, adjacent to setae st1 and between st2 and st3, respectively), surface of sternal shield finely reticulated, more distinct anterolaterally, otherwise smooth ( Figs 19 View FIGURES 18–22 , 24 View FIGURES 23–30 ). Metasternal platelets absent, one pair of simple metasternal setae st4 (17–20) and pore-like iv3 inserted on soft cuticle posterior to sternal shield. Endopodal plates II/III completely fused to sternal shield, endopodal plates III/IV elongate, narrow and curved. Genital shield tongueshaped, length 110–114, maximum width 58–65, shield slightly inflated behind st5 and rounded posteriorly. Surface without any distinct reticulation, almost completely smooth, except two diagonal lines in posterior part ( Figs 19 View FIGURES 18–22 , 24 View FIGURES 23–30 ). Shield flanked by a pair of minute narrow platelets; paragenital poroids located on soft cuticle lateral to shield near seta st5. Anal shield subtriangular, length 42–47, width 50–55, anterior half with lineate ornamentation, with a pair of lateral pores (gv3), para-anal setae (13–15) slightly shorter than post-anal seta (15–17), cribrum small. Soft opisthogastric cuticle surrounding genital and anal shields with one pair of sub-oval metapodal plates (9–11 long 1–3 wide) and nine pairs of setae (Jv1–Jv5, Zv1–Zv 4); all setae uniform in length (13–16) and thickness ( Figs 19 View FIGURES 18–22 , 23 View FIGURES 23–30 ). Exopodal and parapodal platelets strip-like behind coxae IV. Peritreme long, extending to posterior of coxa I, peritrematal shield narrow, free from exopodal shields, post-stigmatal section of peritrematal shield elongated, slender and ensiform, its tip extending to mid-level of coxa IV, with four pore-like structures; three lyrifissures ip and a gland pore gp ( Fig. 25 View FIGURES 23–30 ).

Gnathosoma ( Figs 20–22 View FIGURES 18–22 , 26–29 View FIGURES 23–30 ). Hypostomal groove with six transverse rows of denticles, each row with about 10–20 small teeth, and smooth anterior and posterior transverse lines ( Figs 20 View FIGURES 18–22 , 26 View FIGURES 23–30 ). Epistome ( Figs 21 View FIGURES 18–22 , 27 View FIGURES 23–30 ) arched with denticulated anterior margin. Hypostome with four pairs of setae, internal posterior hypostomal setae h1 longest (20–23), h2 (10–13), h3 (13–17), palpcoxal setae (pc) (16–19) ( Figs 20 View FIGURES 18–22 , 26 View FIGURES 23–30 ). Corniculi robust and horn-like, reaching mid-level of palp femur. Internal malae with median and lateral projections, fringed, inner lobes touching with outer lobes; labrum with pilose surface. Chaetotaxy of palps: trochanter 2, femur 5, genu 6, tibia 14, tarsus 15, all setae smooth and needle-like except al on palp femur lanceolate shape and al, d1 on palp genu thickened and apically spatulate, palp tarsal claw three-tined ( Fig. 28 View FIGURES 23–30 ). Fixed digit of chelicera with three distal teeth of various sizes, a setaceous pilus dentilis, dorsal cheliceral setae prostrate, arthrodial membrane with a rounded flap and normal filaments and cheliceral lyrifissures distinct, movable digit with two teeth ( Figs 22 View FIGURES 18–22 , 29 View FIGURES 23–30 ).

Legs ( Figs 31–34 View FIGURE 31–34 ). Legs II and III short (240–250, 206–219), I and IV longer (338–345, 315–327). Chaetotaxy normal for free living Laelapidae : Leg I ( Fig. 31 View FIGURE 31–34 ): coxa 0 0/1, 0/1 0, trochanter 1 1/2, 0/1 1 (ad lanceolate shape, see Fig. 30 View FIGURES 23–30 ), femur 2 2/1, 3/3 2, genu 2 3/2, 3/1 2, tibia 2 3/2, 3/1 2. Leg II ( Fig. 32 View FIGURE 31–34 ): coxa 0 0/1, 0/1 0, trochanter 1 0/1, 0/2 1, femur 1 3/1, 2/2 1 (av thickened), genu 2 3/1, 2/1 2, tibia 2 2/1, 2/1 2 (all ventral setae thickened). Leg III ( Fig. 33 View FIGURE 31–34 ): coxa 0 0/1, 0/1 0, trochanter 0 1/2, 0/1 1, femur 1 2/1, 1/0 1, genu 2 2/1, 2/1 1 (all ventral setae thickened), tibia: 2 1/1, 2/1 1 (all ventral setae thickened). Leg IV ( Fig. 34 View FIGURE 31–34 ): coxa 0 0/1, 0/0 0, trochanter 1 0/2, 0/1 1, femur 1 2/1, 1/0 1, genu 2 2/1, 3/0 1, tibia 2 1/1, 3/1 2 (all ventral setae thickened). Tarsi II IV with 18 setae (3 3/2, 3/2 3 + mv, md). All pretarsi with well developed paired claws and rounded pulvilli and a long thin stalk, ventral and lateral setae on tarsus II–IV thickened.

Insemination structures: Not seen, apparently unsclerotised.

Male and immatures. Unknown.

Etymology. The species name setillus refers to the short length of dorsal shield setae.

Differential diagnosis. The palp tarsal claw is usually two-tined in Gaeolaelaps, rarely three-tined, and according to Kavianpour et al. (2018), a three-tined tarsal claw occurs in only four species of Gaeolaelaps — G. bregetovae ( Shereef & Afifi, 1980) , G. elongatus ( Hirschmann, 1969) , G. queenslandicus ( Womersley, 1956) , and G. urumiensis Kavianpour et al., 2018 . Gaeolaelaps setillus can be easily distinguished from all these species by its dorsal shield with 38 pairs of very short setae, S5 on soft cuticle posterior to shield (vs. 39 pairs (including two pairs of Zx) in G. bregetovae , G. elongatus , G. urumiensis and 37 pairs (without Zx setae) in G. queenslandicus ), elongated poststigmatal section of peritrematal shield (slender and ensiform) (vs. not elongated in G. bregetovae , G. elongatus and G. queenslandicus ), dorsal shield oval-shaped and covering most of dorsal idiosoma (vs. tapering from anterior to posterior until a rounded posterior end in G. elongatus and G. queenslandicus ) and additional character separating all these species include the shape of ad on trochanter of leg I which is lanceolate in G. setillus .

In the classification of Karg (1982), G. setillus falls into the schusteri species group of Hypoaspis (Gaeolaelaps) , because its genital shield is of normal size and shape and moderately separated from the anal shield, supernumerary setae Jx between J -series present and anal shield approximately as wide as long.

Gaeolaelaps setillus is most similar to G. orientalis ( Hafez et al., 1982) and G. sitalaensis ( Bhattacharyya,

1965) in general appearance, but these species can be separated by the following combination of characters. The dorsal setae in G. setillus are extremely short, while in G. orientalis and G. sitalaensis the dorsal setae are much longer, and some setae long enough to reach the base of the next posterior seta in series. Dorsal shield has 38 pairs setae in G. setillus but 39 pairs in G. sitalaensis . Dorsal shield has 38 pairs setae in both G. setillus and G. orientalis (opisthonotal region in both species with 16 pairs of setae) but in G. setillus , S5 is in the soft cuticle posterior to shield, while in G. orientalis, Zx 3 is missing. Palp tarsal claw is three-tined in G. setillus but two-tined in G. orientalis and G. sitalaensis . Moreover, the peritreme in Gaeolaelaps setillus is longer than that in G. orientalis (extending to posterior of coxa I in G. setillus but extending to mid-level of coxa II in G. orientalis ).