Gymnolaelaps messor, Joharchi, Omid, Halliday, Bruce, Saboori, Alireza & Kamali, Karim, 2011

Joharchi, Omid, Halliday, Bruce, Saboori, Alireza & Kamali, Karim, 2011, New species and new records of mites of the family Laelapidae (Acari: Mesostigmata) associated with ants in Iran, Zootaxa 2972, pp. 22-36 : 23-25

Gymnolaelaps messor sp. nov.

( Figures 1–9 )

Specimens examined. Holotype, female, Iran, Karaj, 36˚01’ N, 51˚09’ E, alt. 1831 m, 15 April 2010, O. Joharchi coll., in nest of Messor sp. ( Formicidae ). Paratypes, six females, same data as holotype (three in JAZM, three in ANIC).

Description. Female.

Dorsal idiosoma. Dorsal shield length 777–798 µm, width 554–588 µm (n = 2) ( Fig. 1 ). Shield oval shaped, lateral margins often bent to become visible ventrally; shield with weak reticulation throughout, more distinct in the opisthonotal section; with 40 pairs of long setae, 22 podonotal, 18 opisthonotal, including three pairs of Zx setae between J and Z setae, setae increasing in length from anterior to posterior (j 1 21–23 µm, J5 118–120 µm), opisthonotal setae long enough to reach well past base of next posterior seta. Podonotal setae smooth, opisthonotal setae slightly serrated ( Fig. 2 ). Opisthonotal region also with two or three unpaired supernumerary seta Jx in each specimen. Central area of shield with two pairs of large circular to oval-shaped pores, other pores minute and inconspicuous.

Ventral idiosoma ( Fig. 3 ). Tritosternum with paired pilose laciniae (99–104 µm), columnar base 32–35 µm long; pre-sternal shields with sclerotised postero-lateral section ornamented with one or two transverse lines, anteromedian section weakly sclerotised. Sternal shield (length 158–181 µm) narrowest between coxae II (149–181 µm), widest between coxae II and III (255–297 µm), with straight anterior margin and slightly concave posterior margin, with three pairs of smooth sternal setae (st 1 52–54 µm, st 2 50–52 µm, st 3 50–52 µm), one pair of lyrifissures adjacent to setae st 1, and a pair of large circular pores between st 2 and st 3; antero-lateral surface of sternal shield with polygonal ornamentation, central area smooth. Metasternal platelets absent; setae st 4 and associated pores located in soft skin; endopodal plates II/III fused to sternal shield, endopodal plates III/IV elongate, narrow, curved. Genital shield broad, length 374–391 µm, maximum width 261–266 µm, posterior edge straight, abutting anal shield, surface with polygonal ornamentation, bearing the genital setae st 5 and three additional pairs of setae on its lateral edges. Circular paragenital pores located on soft skin near the edge of genital shield, between seta st 5 and a pair of minute narrow platelets. Anal shield subtriangular (106–125 µm long × 156–161 µm wide); its anterior half with lineate ornamentation; with a pair of circular lateral pores; para-anal setae similar in length to unpaired post-anal seta (20–23 µm). Opisthogastric skin with one pair of oval metapodal plates (length 40–42 µm) and nine pairs of smooth setae (Jv1 75–78 µm, Jv2 50–53 µm, Jv 3 25–28 µm, Jv5 87–90 µm, Zv1 50–55 µm, Zv 2 30–35 µm). Large triangular podal shields present posterior to coxae IV, similar in texture and appearance to other ventral sclerites; a pair of minute irregular platelets present between the metapodal and exopodal plates behind coxa IV. Peritreme extending from coxa IV to anterior level of coxa I; peritrematal shield wide, with two protrusions on outer margin, post-stigmatal section conspicuous, with three pairs of post-stigmatal pores, and one pair of small pores just anterior to the stigmata; fused with dorsal shield anterior to seta r2.

Gnathosoma . Hypostomal groove with six rows of denticles each bearing four or five small teeth except third row with two large teeth, and smooth anterior and posterior transverse lines ( Fig. 4 ). Corniculi robust and hornlike, reaching mid-level of palp femur. Internal malae complex, with three pairs of lobes; inner lobes narrow, with serrated edges; medial lobes slightly shorter than inner lobes, with strongly serrated edges; outer lobes long, narrow, pointed, with some serration at base of of medial margin. Palp chaetotaxy: trochanter 2, femur 5, genu 6, tibia 14, tarsus 15; genu with a distinct dorso-distal triangular condyle; all setae smooth and needle-like; palp tarsal claw with three pointed tines of unequal length ( Fig. 5 ). Epistome irregularly denticulate ( Fig. 6 ). Fixed digit of chelicera with a small triangular proximal tooth, a slightly larger median tooth, and two small distal teeth ( Fig. 7 ); pilus dentilis moderately robust; dorsal seta short, thick, prostrate; movable digit with two large teeth; arthrodial membrane with a rounded flap and a row of short filaments.

Legs. Legs II and III short (654–660 µm, 643–663 µm), I and IV longer (861–870 µm, 910–912 µm). Chaetotaxy normal for free-living Laelapidae : Leg I: coxa 0 0/1 0/1 0, trochanter 1 1/2 0/1 1, femur 2 3/2 2/2 2 (pl 1 and pl 2 thick), genu 2 3/2 3/1 2, tibia 2 3/2 3/1 2. Leg II: coxa 0 0/1 0/1 0, trochanter 1 0/1 0/2 1, femur 2 3/1 2/2 1, genu 2 3/1 2/1 2, tibia 2 2/1 2/1 2. Leg III: coxa 0 0/1 0/1 0, trochanter 1 0/1 0/2 1, femur 1 2/0 1/1 1, genu 2 2/1 2/ 1 1 (ventral setae all thick, pv 47 µm, al 1 54 µm, al 2 57 µm, pd 1 47 µm, pl 1 42 µm), tibia 2 1/1 2/1 1 ( Fig. 8 ). Leg IV: 0 0/1 0/0 0, trochanter 1 0/1 0/2 1, femur 0 2/1 1/1 1 (dorsal setae all thick), genu 2 2/1 3/0 1 (ventral seta long and thick, av 1 62 µm, ad 1 71 µm, ad 2 82 µm, pd 1 62 µm, pd 2 62 µm, pd 3 57 µm, al 2 74 µm), tibia 2 1/1 3/1 2 (ventral setae long and thick, av 1, av 2 74 µm, pd 1, pd 2 67 µm, pd 3 64 µm) ( Fig. 9 ); all setae fine and needle-like unless otherwise noted. Tarsi I–IV with 18 setae 3 3/2 3/2 3 + mv, md. All pre-tarsi with a pair of claws and a long thin membranous ambulacrum (pre-tarsus length leg I 45 –47 µm, leg II 50 –52 µm, leg III 45 –47 µm, leg IV 55 –57 µm).

Insemination structures not seen, apparently unsclerotised.

Etymology. The name of this species refers to its occurrence in nests of ants of the genus Messor .

Notes. Gymnolaelaps messor differs from almost all other species in the genus by the long setae in the posterior half of its dorsal shield. Only four other species have such long setae. Gymnolaelaps messor differs from G. annectans Womersley, 1955 (= G. nidicorva (Evans & Till, 1966)) and G. unospinosus ( Karg, 1978) also by the presence of large subtriangular podal plates behind coxa IV (absent in G. nidicorva and G. unospinosus ). It differs from G. reniculus ( Karg, 1981) by the much greater width of its genital, anal and peritrematal shields, and from G. australicus Womersley, 1956 , by the straight posterior edge of its genital shield (rounded in G. australicus ). The new species is also distinctive in having three pairs of Zx setae on the dorsal shield, between the J and Z series setae.

Figures

FIGURES 1 – 9. Gymnolaelaps messor sp. nov., female. 1. dorsal shield; 2. dorsal seta Zx enlarged; 3. ventral idiosoma; 4. hypostome; 5. palp tarsal claw; 6. epistome; 7. chelicera; 8 genu III, dorsal aspect; 9. genu and tibia IV, dorsal aspect. Scale bar = 100 μm for 1 and 3, 50 μm for 4, 6, 7; 10 μm for 5. Figure 2 not to scale.