Gaeolaelaps hajiqanbari Joharchi & Nemati, 2022

Joharchi, Omid, Nemati, Alireza, Döker, İsmail & Khaustov, Vladimir A., 2022, Gaeolaelaps hajiqanbari sp. nov. (Acari: Mesostigmata: Laelapidae) from Western Siberia, Russia, Persian Journal of Acarology 11 (1), pp. 11-22 : 12-19

Gaeolaelaps hajiqanbari Joharchi & Nemati sp. nov. ( Figs. 1–20 )

http://zoobank.org/ urn:lsid:zoobank.org:act:EE3D32E6-B68B-4417-BE1B-4F9796A931C6

Diagnosis (female) Female with dorsal shield gently tapering from level of S4 setae, with rounded shape of the posterior region, bearing 39 pairs of moderately smooth and long setae, more or less reaching base of next seta, setae J5, Z5 and S5 with 1–3 small barbs; lacking apparently gland openings gd1, gd4, gd5; narrow strip of soft cuticle surrounding dorsal shield with two pairs of R setae (r6, R1); sternal shield reticulate in lateral regions, smooth medially (or faintly reticulate), with a small triangular protuberance on outer lateral sides at level between setae st1 and st2 (in all examined specimens), moderately concave both anterior and posterior margins, with setae st1 on pointed edge of two anterior extensions of shield, ratio of shield length/width (at broadest level) ≃ 0.68; genital shield flask-shaped, slightly expanded laterally past level of setae st5, ratio of length/ width (at broadest level) ≃ 1.95, shield smooth except for an inversely Y-shaped line; the distance midline between posterior margin of genital shield and anterior margin of anal shield nearly as long as anal opening; anal shield longer than wide, the ratio of length/width (at broadest level) ≈ 1.17, circumanal setae smooth; post anal seta slightly thicker and longer than para-anals; labrum considerably short (slightly longer than corniculi) with completely rounded apex (not pointed), fixed cheliceral digit with 9–10 teeth (including at least four teeth posterior to pilus dentilis); internal malae with long median projections and two additional pairs of lateral projections of similar length, palp apotele with two tines (without a minute basal tine in all examined specimens); soft opisthogastric cuticle bearing 15 pairs thick setae, each arising on minute sclerotized platelet and with 1–4 small barbs; peritremes relatively extending anteriorly to level of acetabulum I; leg setae mostly thickened and some inserted on small tubercles (including leg I) and leg I longer than length of idiosoma.

Description (female, n = 7)

Dorsal idiosoma ( Figs. 1 , 7 ) – Dorsal shield oval-shaped, 547–555 long, 310–331 wide, reticulation more distinct in the lateral sections, covering most of dorsal idiosoma but leaving narrow strip of soft lateral cuticle; shield narrowing from level of setae r3, progressively tapering until s6, then subparallel from S1 to level of S3, where it then gently tapers until rounded posteriorly; shield with 39 pairs of setae of almost uniform length (34–43), except setae j1 (43–45), z1 (21–23) shortest, Z5 (54–62) longest, all setae relatively long and reaching base of following setae, setae of central area shorter (not reaching base of following setae); setae J5, Z5 and S5 with 1–3 small barbs ( Figs. 1 , 7 ); without unpaired setae. Shield with about 20 pairs of discernible pore-like structures, including 16 poroids and four gland openings; lacking apparently gland openings gd1, gd4, gd5, see Figures 1 and 7 .

Ventral idiosoma ( Figs. 2 , 8–11 ) – Tritosternum with paired pilose laciniae (104–113), fused basally (10–13), columnar base 30–36 × 14–16 wide; presternal area lightly sclerotized, with a few transverse curved lines. Sternal shield (length 110–116) narrowest between coxae II (95–99), widest (160–171), anterior and posterior margin of shield moderately concave, anterolateral corners narrowly extending between coxae I–II, distally bearing gland pores gvb; endopodal elements between coxae II and III fused with shield; with a small triangular protuberance on outer lateral sides at level between setae st1 and st2 (in all examined specimens), shield bearing gland pores gv1 and three pairs of smooth setae (st1 43–45, st2 39–42, st3 39–42) and two pairs of slit-shaped pore-like structures (iv1 adjacent to setae st1; iv2 between st2 and st3), setae not reaching base of next setae; sternal shield with reticulate ornamentation in longitudinally lateral parts, longitudinally median part smooth (or faintly reticulated) ( Figs. 2 , 8, 9 ). Metasternal setae st4 (34–36) and metasternal poroids located on soft integument; metasternal platelets absent. Endopodal plates II/III completely fused to sternal shield, endopodal plates III/IV elongate, narrow and curved. Genital shield flask-shaped, slightly expanded laterally past level of setae st5 ( Figs. 2 , 8, 10 ), length 215–224, maximum width 110–115, posterior margin rounded, anterior hyaline margin of shield irregularly convex and usually slightly covering posterior margin of sternal shield, with an inverse Y–shaped ornamentation, otherwise smooth; genital shield separated from anal shield by almost length of anal opening, setae st5 (30–32) inserted on lateral margins of shield, approximately at level of posterior edge of coxae IV. Poroids iv5 inserted on soft cuticle, at level of tip of st5. Two tiny postgenital sclerites at level of Zv1 present. Anal shield subtriangular, 101–105 long, 83–89 wide, with lineate-reticulate ornamentation, anterior margin of shield rounded, circumanal setae smooth, postanal seta (32–35) slightly longer than para-anal setae (30–32); cribrum well developed, with two single rows of spicules each extending from cribrum to near base of para-anal setae; anal opening located at mid-level of shield; pair of glands gv3 inserted on shield lateral margins, at level between para-anal setae and posterior edge of anus ( Figs. 2 , 8, 11 ).

Peritrematal shield narrow developed posteriorly beyond stigmata, almost reaching posterior margin level of coxae IV, extending anteriorly and fused to dorsal shield at base of level seta z1; bearing two gland pores (gp) and three poroids (ip) (including post-stigmatic section that bearing three pore-like structures, two lyrifissures ip and a gland pore gp) ( Fig. 2 ), peritremes extending from stigmata to level of acetabulum I ( Fig. 2 ). Exopodal platelets between coxae II–III divided into sclerotized strips along coxae II and III, those behind coxae III–IV and parapodal platelets fused, strip-like, extending narrowly behind coxae IV, bearing gland pore gv2. One pair of minute paragenital platelets anterior to setae ZV1. Soft opisthogastric cuticle bearing 15 pairs thick setae, each arising on minute sclerotized platelet and mostly with 1–4 small barbs and four pairs of poroids (four ivo; ivp), Jv1, Jv2 (29–32), Jv3 (35–39), Jv4 (42–45), Jv5 (56–59), Zv1 (25–27), Zv2 (37–40), Zv3 (26–28), Zv4 (36–38), Zv5 (50–54), two pairs of metapodal plates present, the anterior small, ovoid and the posterior larger, fusiform (20–26 long × 5–7 wide) ( Figs. 2 , 8, 11 ).

Gnathosoma ( Figs. 3–6 , 12–14 ) – Epistome subtriangular, and irregularly denticulate ( Fig. 4 ). Internal malae fringed, with a pair of thick, contiguous median projections, and two pairs of thinner lateral projections, the inner pair shortest. Labrum considerably short (slightly longer than horn-like corniculi), with completely rounded apex ( Figs. 3 , 12 ). Hypostomal setae smooth, h1 (48–50)> palpcoxal pc (39–41)> h3 (37–39)> h2 (27–30) ( Figs. 3 , 12 ). Deutosternum with six rows of two denticles close to each of lateral margins except first and last rows, with three and four denticles, respectively ( Figs. 3 , 12 ). Chaetotaxy of palps: trochanter 2, femur 5, genu 6, tibia 14, tarsus 15, all setae needle-like except al1 and al2 of palpgenu and al of palpfemur thickened, palptarsus apotele with two tines ( Fig. 13 ). Supralabral process with a narrow and undivided projection ( Fig. 5 ). Fixed digit of chelicera with an offset and subapical tooth (gabelzhan), followed by 8–9 teeth, a setaceous pilus dentilis, dorsal cheliceral seta prostrate, arthrodial membrane with a rounded flap and normal filaments; cheliceral lyrifissures distinct, movable digit of chelicera bidentate ( Figs. 6 , 14 ).

Legs ( Figs. 17–20 ) – Legs II (452–458) and III, (442–450) short, I (607–612) and IV (639–645) longer. Chaetotaxy normal for free-living Laelapidae : Leg I ( Fig. 3A ): coxa 0-0/1, 0/1-0, trochanter 1-1/2, 1/0-1 (al, ad and pd thickened), femur 2-2/1, 3/3-2 (all dorsal thickened and ad1 inserted on small tubercles, Fig. 15 ), genu 2-3/2, 3/1-2 (ad1 inserted on small tubercles), tibia 2-3/2, 3/1-2. Leg II ( Fig. 18 ): coxa 0-0/1, 0/1-0, trochanter 1-0/1, 0/2-1, femur 2-3/1, 2/2-1 (all dorsal thickened and inserted on small tubercles), genu 2-3/1, 2/1-2 (av thickened and pd1, pd2 inserted on small tubercles), tibia 2-2/1, 2/1-2 (ventral setae thickened). Leg III ( Fig. 19 ): coxa 0-0/1, 0/1-0, trochanter 1-1/1, 0/1- 1, femur 1-2/1, 1/0-1, genu 2-2/1, 2/1-1 (ventral setae thickened and dorsal setae inserted on small tubercles), tibia: 2-1/1, 2/1-1 (ventral setae thickened and pd1, pd2 inserted on small tubercles). Leg IV ( Fig. 20 ): coxa 0-0/1, 0/0-0, trochanter 1-1/2, 0/1-0 (ad thickened and inserted on small tubercles), femur 1-2/1, 1/0-1 (ad1, ad2 thickened and inserted on small tubercles, Fig. 16 ), genu 2-2/1, 3/0-1 (av thickened and ad1, ad2 inserted on small tubercles), tibia 2-1/1, 3/1-2 (al1, pl1, av, pv thickened and al2, pd3 inserted on small tubercles). Tarsi II-IV with 18 setae (3- 3/2, 3/2-3 + mv, md); almost all setae on tarsus II-IV thickened, see Figures 18–20 . All pretarsi with well-developed paired claws, rounded pulvilli and normal ambulacral stalk.

Insemination structures – Not seen, apparently unsclerotized.

Male and immatures – Unknown.

Etymology

This species is named in honor of our friend and colleague, a famous acarologist, Dr. Hamidreza Hajiqanbar (Tarbiat Modares University, Tehran, Iran), for his extensive contributions to our knowledge of morphology, systematics and phylogenetics of heterostigmatic mites. He passed away unexpectedly on October 2021, at the age of 48, resulting in an irretrievable loss for the international scientific community.

Type material

Holotype, female, Nazyvayevsky District , Omsk Oblast, Western Siberia, Russia ( Fig. 21 ), 55° 31′ N, 70° 49′ E, 27 August 2020, A.A. Khaustov coll., from soil of salt marsh (in TSUMZ) . Paratypes, six females, same data as holotype (in TSUMZ) .

Remarks

The new species can easily be distinguished from all members of Gaeolaelaps by having relatively unique characters: seta st1 on pointed edge of two anterior extensions of sternal shield. In most species of Gaeolaelaps the seta st1 is well located inside the sternal shield, seta st1 is off the sternal shield in the presternal region in only eight species of Gaeolaelaps (see Kafi et al. 2020). This feature can be difficult to discern, and in some of these species seta st1 is on pointed edge of two anterior extensions of shield, as was found just in two described species of Gaeolaelaps - G. jondishapouri Nemati and Kavianpour, 2013 and G. changlingensis ( Ma, 2000) . The new species is closely related to G. jondishapouri [redescribed by Kazemi et al. (2014)] and G. changlingensis ( Ma, 2000) by sharing this character state which is described from Iran and China, respectively. Gaeolaelaps hajiqanbari differs from both G. jondishapouri and G. changlingensis by the rounded shape of the posterior region of the dorsal shield ( Figs. 1 , 7 ), while in both G. jondishapouri and G. changlingensis this region is described as V-shaped (subtriangular) or bell-shaped; genital shield long, extending close to anal shield, the distance midline between posterior margin of genital shield and anterior margin of anal shield at most as long as anal opening in G. hajiqanbari ( Figs. 2 , 8, 11 ), while genital shield much shorter, the distance midline between posterior margin of genital shield and anterior margin of anal shield nearly as long as anal shield in both G. jondishapouri and G. changlingensis ; soft opisthogastric cuticle bearing 15 pairs thick setae (e.g. Jv4, Jv5, Zv4, Zv5 considerably thickened) ( Figs. 2 , 11 ), while soft opisthogastric cuticle bearing 8–9 thin and needlelike in both G. jondishapouri and G. changlingensis ; leg I without thickened setae in both G. jondishapouri and G. changlingensis , while dorsal setae on trochanter and femur I considerably thickened and some inserted on small tubercles in G. hajiqanbari ( Figs. 15 , 17 ); ad1–2 on femur IV considerably thickened and some inserted on small tubercles in G. hajiqanbari ( Figs. 16 , 20 ), while only ad2 slightly thickened in G. jondishapouri ; labrum considerably short (slightly longer than corniculi) with completely rounded apex in G. hajiqanbari ( Figs. 3 , 12 ), while labrum acuminate and considerably longer than corniculi in G. jondishapouri ; fixed cheliceral digit with 9–10 teeth in G. hajiqanbari ( Figs. 6 , 14 ), while fixed digit of chelicera at most bearing eight teeth in both G. jondishapouri and G. changlingensis ; dorsal setae mostly simple, except setae J5, Z5 and S5 with 1– 3 small barbs in G. hajiqanbari ( Figs. 1 , 7 ), while most of dorsal setae with 1–3 barbs in G. jondishapouri ; dorsal shield lacking apparently gland openings gd1, gd 5 in G. hajiqanbari ( Figs. 1 , 7 ), while both are present in G. jondishapouri ; a strip-like postgenital sclerite is present in G. jondishapouri , while apparently absent in G. hajiqanbari , palp apotele with three tines, including a minute basal tine in G. jondishapouri (see Kazemi et al. 2014), while palp apotele clearly with two tines (without a minute basal tine) in G. hajiqanbari ( Fig. 13 ). All above mentioned morphological differences were confirmed via examination of the type materials of G. jondishapouri . The genus Gaeolaelaps needs a thorough revision and it is necessary to split it into smaller monophyletic groups. However, we suspect that such a unique character where seta st1 is on the pointed edge of two anterior extensions of sternal shield occurs in other species, which we may have overlooked, or that are still undescribed, and all species with this character may form a monophyletic group; however, a comprehensive revision of all Gaeolaelaps species is necessary to resolve their relationships.

Figures

Figure 1. Gaeolaelaps hajiqanbari Joharchi & Nemati sp. nov. (female) – Dorsal idiosoma.

Figure 2. Gaeolaelaps hajiqanbari Joharchi & Nemati sp. nov. (female) – Ventral idiosoma.

Figures 3–6. Gaeolaelaps hajiqanbari Joharchi & Nemati sp. nov. (female) – 3. Subcapitulum; 4. Epistome; 5. Supralabral process; 6. Chelicera.

Figures 7–16. DIC micrographs of Gaeolaelaps hajiqanbari Joharchi & Nemati sp. nov. (female) – 7. Idiosoma in dorsal view; 8. Idiosoma in ventral view; 9. Sternal shield; 10. Genital shield; 11. Anal shield and soft opisthogastric cuticle; 12. Subcapitulum; 13. Distal portion of palp, with a focus on apotele; 14. Chelicera; 15. Fe I; 16. Fe IV.

Figures 17–20. Gaeolaelaps hajiqanbari Joharchi & Nemati sp. nov. (female) – 17. Leg I (trochanter-tibia); 18. Leg II; 19. Leg III; 20. Leg IV.

Figure 21. Collecting site in Nazyvayevsky District, Omsk Oblast, Western Siberia, Russia.