Halodarcia carabidophila Evans and Fain, 1995

Trach, V. A., 2016, New records of carabid-associated mesostigmatic mites (Acari: Mesostigmata) from Ukraine with description of adults of Halodarcia carabidophila Evans and Fain, 1995 (Halolaelapidae), Acarologia 56 (4), pp. 587-601 : 589-593

Halodarcia carabidophila Evans and Fain, 1995

( Figures 1 and 2 )

Material examined — two deutonymphs from Agonum sp. , Ukraine, Odessa Region, Berezovka District, vicinity of Berezovka (47°10’N, 30°56’E), floodplain forest near Tiligul River, 01 Apr. 2001, V. Trach coll.; seven deutonymphs from Agonum sp. , same locality, 16 Apr. 2003, V. Trach coll.; ten deutonymphs from Agonum sp. , same locality, 26 Mar. 2011, V. Trach coll.; one deutonymph from Agonum sp. , Ukraine, Odessa Region, Belyaevka District, vicinity of Troitskoe (46°32’N, 30°00’E), flooplain forest near Turunchuk River, 21 Mar. 2009, V. Trach coll.; one deutonymph from undetermined Carabidae , Ukraine, Odessa Region, Belgorod-Dnestrovsk District, vicinity of Zatoka (46°01’N, 30°24’E), Black Sea Coast, 04 July 2010, V. Trach coll.; three deutonymphs from Necrodes littoralis (Linnaeus, 1758) ( Coleoptera : Silphidae ), Ukraine, Odessa Region, Belyaevka District, vicinity of Belyaevka (46°25’ N, 30°10’ E), floodplain forest near Dniester River, 22 Juny 2011, V. Trach coll.

Distribution — Belgium ( Evans and Fain, 1995).

Remarks — Deutonymphs of Halodarcia carabidophila was described from carabids Agonum spp. and Pterostichus spp. from Belgium ( Evans and Fain, 1995). Records of H. carabidophila on the necrophagous silphid N. littoralis may represent a fortuitous attempt to disperse phoretically on an accidental host. The genus Halodarcia is new to the fauna of Ukraine. The adult stages of H. carabidophila obtained in the laboratory are herein described for the first time.

Diagnosis — Adult female with 24 pairs of setae (j2-j6, z2-z6, s1, s3-s5, J1, J2, J4, J5, Z1-Z5, S2) on dorsal shield; sternal shield divided medially; epigynal shield rounded posteriorly; ventri-anal shield elongated, with 2 pairs of preanal setae (JV2, JV3) and circum-anal setae; soft opisthosomal integument hypertrichous; gnathotectum with denticulate lateral margins and tapering undivided median process. Gnathotectum of adult male with smooth lateral margins and tapering median process; spermatodactyl large and curved, longer than movable digit. Deutonymph with 15 pairs of setae (j1-j6, z2-z6, s2, s3, s5, s6) on podonotal shield and normally 10 pairs of setae (J1, J2, J4, J5; Z1-Z5, S2) on opisthonotal shield, setae S1 on soft cuticle; cheliceral digits stout with teeth of movable digit weak.

Description of female (n = 4) — Dorsum ( Figure 1A ). Dorsal shield obovate, length 622 – 651, maximum width 353 – 363, tapering anteriorly from setae s5 and posteriorly from setae Z1. Surface of shield essentially smooth. Dorsal shield with 24 pairs of setae (j2-j6, z2-z6, s1, s3-s5, J1, J2, J4, J5, Z1- Z5, S2), 12 pairs of distinguishable pores and posterodorsal cribrum (terminology by Krantz, 2016), setae J3 absent. Setae j1 and z1 located on fused anteriorly peritrematal shields. Fusion of the dorsal shield with peritrematal shields indistinguishable. Anterior soft lateral integument with 7 pairs of setae (s2, s6, r2-r6) and one pair of pores; posterior soft lateral integument hypertrichous, with about 20 pairs of setae, pores not distinguishable. Most dorsal setae slightly serrated, length 19 – 29.

Venter ( Figures 1 B-D) — Tritosternum with elongated base and pilose laciniae, base of tritosternum length 36 – 38, laciniae length 50 – 57. Presternal shields elongated, free. Sternal shield divided medially; shield with elongate antero-lateral corners, shield surface evenly sclerotized, with faint longitudinal and transverse lines, bearing 3 pairs of setae and 2 pairs of pores, setae st2 and st3 thickened. Length st1 29 – 34, st2-st3 25 – 29, maximum width of sternal shield at anterior part, 235 – 252 including endopodal strips. Sternal shield fused with endopodal plates of coxae II/III, coxae III/IV and parapodal platelets. Setae st4 located on metasternal shields, length st4 34 – 38. Pores iv3 lacking. Epigynal shield triangular, anteriorly elongated and pointed, posterior margin rounded, bearing simple setae st5. Epigynal shield length 189 – 202, maximum width 126 – 160, length st5 40 – 46. Inguinal gland platelet with two gv2 pores, pores iv5 present. Ventri-anal shield elongated and reticulated, with rounded anterolateral corners, length 185 – 202, maximum width 109 – 118, cribrum well developed. In one specimen seta JV2 on separate plate ( Figure 1C ). Shield bearing 2 pairs of simple preanal setae (JV2, JV3), para-anal, post-anal setae and pair of pores (gv3), length of preanal setae 36 – 55, length of para-anal setae 36 – 40, length of post-anal seta 38 – 42. Soft opisthosomal integument hypertrichous, with 20 – 21 pairs of setae (S1, S3-S5, R1-R7 and 9 – 10 pairs setae of UR -series) and pair of metapodal plates, length 8 – 11, width 25 – 32. Longer setae smooth, length 38 – 46, shorter setae slightly serrated, length 21 – 29. Peritrematal shields narrowly fused with exopodal plates of coxae III/IV, bearing at least 2 pairs of pores, shields anteriorly wealky reticulated, peritremes extending to level of dorsal setae z2. Exopodal plates of coxae II/III free. Spermathecal structures indiscernible.

Gnathosoma — Gnathotectum ( Figure 1E ) with denticulate lateral margins and tapering undivided median process. Subcapitulum 189 – 197 maximum width, with seven rows of deutosternal denticles, 15 – 25 denticles per row, subcapitular groove indistinct ( Figure 1F ). Hypostomal setae simple, pc length 38 – 42, hp1 32 – 36, hp2 27 – 29, hp3 36 – 40. Corniculi horn-like. Palp length 231 – 239, chaetotaxy of palps 2–5–6–14–15, setae v1 on trochanter, d1, d3, pl on femur slightly serrated, setae v2 on trochanter, al on femur, al1 on genu serrated, seta al2 on genu brush-like, palptarsal apotele 3-tined. Second cheliceral segment length 155 – 166, fixed digit with 3 – 4 proximal teeth and one small pre-apical teeth, pilus dentilis short, movable digit with 4 – 5 teeth ( Figure 1G ).

Legs ( Figures 2 A-D) — Leg lengths: I 688 – 725, II 549 – 586, III 502 – 530, IV 688 – 707. Chaetotaxy: leg I (from coxa to tibia): 2, 6 (1–0/1–1/2–1), 13 (2–3/1–2/3–2), 13 (2–3/2–3/1–2), 13 (2–3/2–3/1– 2); leg II: 2, 5 (1–0/1–0/2–1), 11 (2–3/1–2/2–1), 11 (2–3/1–2/1–2), 10 (2–2/1–2/1–2), 18 (3–3/3–1/1– 2/2–3); leg III: 2, 5 (1–0/1–0/2–1), 6 (1–2/1–1/0–1), 9 (2–2/1–2/1–1), 8 (2–1/1–2/1–1), 18 (3–3/3–1/1– 2/2–3); leg IV: 1, 5 (1–0/1–0/2–1), 6 (1–2/1–1/0– 1), 10 (2–2/1–3/1–1), 10 (2–1/1–3/1–2), 18 (3–3/3– 1/1–2/2–3). Claws I-IV well developed, ambulacral stalk of legs II-IV with long acuminate paradactyli. Most setae slightly thickened and serrated. Coxae II with small anterior spine.

Description of male (n = 7) — Dorsum. Dorsal shield fused anteriorly and laterally with peritrematal shields, and fused posteriorly with ventrianal shield, length 456 – 530, maximum width 353 – 409. Surface of shield with faint scale-like ornamentation throughout (in contrast with that of female). Chaetotaxy as in female. Dorsal setae length 17 – 27.

Venter ( Figure 1H ) — Base of tritosternum length 17 – 19, laciniae length 34 – 38. Sternogenital shield length 219 – 235, surface essentially smooth, bearing 5 pairs of simple setae (length 25 – 32). Soft opisthosomal integument not hypertrichous. Large ventri-anal shield fused with dorsal and peritrematal shields, bearing 10 pairs of simple preanal setae (JV1-JV5, ZV1-ZV5), para-anal, postanal setae and pair of pores. Length of preanal setae 29 – 38, length of para-anal setae 29 – 36, length of post-anal seta 32 – 36. Surface of ventri-anal shield ornamentation as for dorsal shield. Other characters as in female.

Gnathosoma — Most features of gnathosoma as in female. Gnathotectum ( Figure 1I ) with smooth lateral margins and tapering median process. Subcapitulum 189 – 197 maximum width, hypostomal setae lengths: pc 25 – 32, hp1 21 – 25, hp2 17 – 21, hp3 21 – 25. Corniculi more pointed than in female ( Figure 1J ). Palps length 185 – 202. Second cheliceral segment ( Figures 1 K-L) length 109 – 126, fixed digit with 2 – 3 tooth, pilus dentilis short, movable digit with one large tooth, spermatodactyl large and curved, longer than movable digit.

Legs — As in female. Leg lengths: I 539 – 632, II 437 – 474, III 391 – 446, IV 549 – 623.

Remarks — At present, all four species of the genus Halodarcia are known from females, three species ( H. carabidophila , H. incideta , H. kargi ) are known from males and three species ( H. carabidophila , H. incideta , H. porolata ) are known from deutonymphs. The key to deutonymphs of the genus Halodarcia was presented by Evans and Fain (1995). The male of H. carabidophila and H. incideta are distinguished from male of H. kargi by the shape of the gnathotectum (in H. kargi anterior margin of gnathotectum with 3 sets of denticulate tips; in H. carabidophila and H. incideta gnathotectum with smooth lateral margins and tapering median process) and the shape of spermatodactyl (in H. kargi weakly curved, approximately equal in length to movable digit; in H. carabidophila and H. incideta spermatodactyl strongly curved, longer than movable digit). The difference between males of H. carabidophila and H. incideta is not clear.

Figures

FIGURE 1: Halodarcia carabidophila Evans and Fain, 1995, female: A – idiosoma, dorsal view (setae of the soft cuticle in the podonotal region on the left side were not drawn); B – idiosoma, ventral view; C-D – variety of shape of anal shields; E – gnathotectum; F – subcapitulum and palp; G – chelicera. Male: H – idiosoma, ventral view; I – gnathotectum; J – corniculus; K – variety of shape of chelicerae. Scale bar: A-D, H 200 µm, E, G, I, K, L 100 µm, F, J 200 µm.

FIGURE 2: Halodarcia carabidophila Evans and Fain, 1995, female: A – leg I (from coxa to tibia); B – leg II; C – leg III; D – leg IV. Scale bar 200 µm.