Mexecheles thailandensis, Fuangarworn & Lekprayoon, 2010

Fuangarworn, Marut & Lekprayoon, Chariya, 2010, Two new species of cheyletid mites (Acari: Prostigmata) from Thailand, Zootaxa 2494 (1), pp. 59-68 : 60-63

Mexecheles thailandensis n. sp.

( Figs. 1–3 )

Female (Holotype and paratype). Gnathosoma ( Figs. 1A, B ) — 140 (137–142) long, 121 (120–122) wide. Peritreme arch-like, with 5 or 6 pairs of segments. Protegmen laterally granulate and medially papillate. Tegmen covered by reticulated pattern and basally papillate. Rostral tip with two pairs of simple adoral setae, or1 and or2. Palpal femur 63 long, 58 wide, outer side strongly convex, with five setae (dF, dG, l”G, v’F and v”F). Setae dF, dG and l”G monaxial, thickened and barbed. Setae v’F and v”F much thinner and filiform. Genu without setae. Palp tibia with three setae, dT, l”T and l’T, all smooth and filiform. Palpal claw with 10 or 11 teeth. Palpal tarsi with four setae of which two dorsal setae (acm and sul) comb-like and two ventral setae (ul’ and ul”) filiform. Solenidion ω also present ventrally. Gnathobase with a pair of filiform setae n.

Idiosoma ( Fig. 1 ). Dorsum ( Fig. 1A ) — Two dorsal shields present and finely striated; propodonotal shield 133 long, 197.5 (195–200) wide, with a pair of eyes, four pairs of lateral setae and five pairs of strongly modified median setae ( Fig. 1 ). Lateral setae spatulate and roughly barbed, about 63–70 long. Median setae stag horn-like, with rosary-like branches. Setae c2 laterally placed on membrane, also spatulate and subequal in length to lateral setae. Hysterosomal shield 131 (125–138) long, 156 (150–163) wide, bearing four pairs of lateral setae and three pairs of median setae similar in shape to those on propodonotal shield. Setae d1 50 long, d2 45 long, e2 45 long, f2 38 long. Setae h1 28 long, born outside hysteronotal shield, setae h2 absent. Membrane striated with microgranules, papillae present at posterior third of hysterosoma. Venter ( Fig. 1B ) — except for coxal plates, integument striate. Ventral setae filiform, smooth, except 3b distinctly thickened and barbed. Aggenital setae ag1–ag3 present, filiform and smooth; setae ag1 about three times longer than ag2 and ag3. Genital setae g1 and g2 and setae ps1–ps3 short, smooth and bifurcate.

Legs ( Figs. 2A–D ) — Leg I longest, about 1.2 times longer than idiosoma. Leg I, 345 (345–345); leg II, 214 (210–215); leg III, 223 (220–225); leg IV 245 (240–250). Setation of legs I–IV (solenidion in brackets) as follows: coxa 2 - 1 - 2 - 2; trochanter 1 - 1 - 2 - 1; femur 2 - 2 - 2 - 2; genu 2(1) - 2 - 2 - 2; tibia 5(1) - 4(1) - 4 - 4; tarsi 8(1)-7(1) - 7 - 7. Setae ft on tarsi I minute, 10 long, solenidia ω 1 121 (120 – 123) long, setae p’ of tarsi I longer than pretarsi. Claw I small; claws of leg II–IV larger, with basal angle. Shape of setae on leg I as follows: setae v’Tr straplike; v’Fe straplike, dFe spatulate; l’Ge and dGe spatulate; (v)Ti, l’Ti and dTi rodlike, l’’Ti filiform; ftTa minute, long as about width of ω 1, (tc)Ta, (p)Ta, (u)Ta, vsTa filiform; setae p’Ta longer than p”Ta and longer than pretarsi; solenidia σ 1 and φ 1 rodlike, ω 1 elongate. Shape of setae on leg II as follows: setae v’Tr straplike; v”Fe straplike, dFe spatulate; dGe fanlike, l’Ge straplike; dTi straplike, v’Ti rodlike, l”Ti straplike, v”Ti filiform; (tc)Ta filiform, (p)Ta pointed rodlike, (u)Ta rodlike and ciliate. Solenidia φ 1 short rodlike, ω 1 rodlike and elongate, 21 (18–25) long. Shape of setae on leg III as follows: v”Tr rodlike, l”Tr straplike; dFe spatulate, l”Fe straplike; dGe fanlike, l”Ge straplike; dTi spatulate, l’Ti and v”Ti rodlike, v’Ti filiform; (tc)Ta filiform, (p)Ta rodlike, (u)Ta rodlike and ciliate. Shape of setae on leg IV as follows: v”Tr rodlike; dFe and l”Fe rodlike; dGe fanlike, l”Ge spaulate; dTi spatulate, v”Ti and l’Ti rodlike, v’Ti filiform; (tc)Ta filiform, (p)Ta rodlike, (u)Ta rodlike and ciliate.

Male (n = 3) ( Figs. 3A, B ). Gnathosoma — 110 (100 – 122) long, 107 (100–115) wide. Peritreme inverted U shaped with five pairs of segments. Ornamentation of tegmen and protegmen similar to those of female. Gnathobase enlarged ventrally. Setae dF, dG and l”G monaxial, thickened and roughly barbed. Setae (v)F smooth and filiform. Palpal tibia with three setae (d, l’ and l”), all smooth and filiform. Tibial claw with 9–11 teeth. Palpal tarsi with eupathidium sul with numerous tines, eupathidia acm, ul’ and ul” smooth and filiform. Solenidion ω short, rodlike, situated ventrally.

Idiosoma. Pear shaped, 238 (225–250) long, 222 (207–233) wide, with two dorsal shields. The shields granulated with weakly formed of reticulated patterns. Propodonotal shield 115 (112–120) long bearing eyes, four pairs of lateral setae (vi, ve, sci and sce) and three pairs of median setae, all spatulate and roughly barbed. Setae ve longest, 58 (55–63) long. Setae c2 on membrane, 43 (38–50) long. Hysteronotal shield bearing three pairs of lateral setae (d2, e2 and f2) and three pairs of median setae, all short, spatulate and roughly barbed. Aedeagus about 41 (38–45) long. Integument around shields striated; microgranules, microtubules and papillae absent. Setae ps1– ps3 present, all bifurcate. Setae g1 and g2 present, g1 short and sickle-like, g2 simple and longer than g1 ( Fig. 3B ). Two pairs of setae ag present.

Legs: Leg I 268 (250–300) long, leg II 167 (155–185) long, leg III 185 (175–200) long, leg IV 190 (185– 200) long. Chaetotaxy similar to those of female except the presence of solenidia on venter of tarsi III and IV and absence of setae l” on femur IV. All claws without basal angle.

Deutonymph (n = 1) ( Fig. 3C ). Gnathosoma – 110 long, 113 wide.

Idiosoma 225 long, 213 wide. Propodonotal shield about 108 long, bearing eyes, four pairs of lateral setae, all spatulate and roughly barbed, and three pairs of shorter median setae. Shield’s surface granulate with reticulate pattern centrally. Setae c2 on platelet, spatulate and roughly barbed. Two hysteronotal shields present, small and oval in shape, each shield bearing two setae. Six pairs of setae on membrane, all spatulate and roughly barbed. Integument striated with microgranules and papillae.

Legs: Leg I 250 long, leg II 150 long, leg III 160 long, leg IV 175 long. Leg I–IV setation (solenidion in brackets) as follows: coxa 2 - 1 - 2 - 2; trochanter 1 - 1 - 2 - 1; femur 2 - 2 - 2 - 1; genu 2(1) - 2 - 2 - 2; tibia 5(1) - 4(1) - 4 - 4; Tarsi 8(1) - 7(1) - 7 - 7. Basal angle of claws absent.

Type materials. Holotype female (CUMZ-AC-2009.01); Salaloy Subdistrict, Tharua District , Ayutthaya Province; ex. bark of fallen Streblus asper tree infested by scolytid beetles; 26. VII. 2009; leg. M. Fuangarworn (Field No. MF 2009-28). One female paratype, three male paratypes and one deutonymph paratype (CUMZ-AC-2009.02 – 06) with same data as holotype. Type deposition – Holotype and paratypes are deposited in the Acarology Collection at Chulalongkorn University Museum of Natural History, Bangkok, Thailand . Female and male paratypes will be deposited in the Acarology Collection at the Ohio State University, Columbus, USA .

Etymology. The new species is named after the country of its type locality, Thailand.

Remarks. In their review of the family Cheyletidae, Summers and Price (1970) included seven species in the genus Mexecheles . Two species, M. votandinii Jeffery, 1975 and M. shiva Bochkov and Ochoa, 2005 , were subsequently added. Therefore, this study brings the known species of Mexecheles to 10 species. The female of M. thailandensis n. sp. is similar to M. virginiensis (Baker) in the presence of monaxial setae dG on the palpal femur; the dorsolateral setae on idiosoma being spatulate; having five pairs of median staghorn-like setae on the propodonotal shield, and the ratio of the length of leg I to idiosoma being 1.2. However, the new species can be distinguished from M. virginiensis by the presence of three pairs of median stag horn-like setae on hysteronotal shield (vs. four pairs in M. virginiensis ), the absence of setae h2 (vs. presence) and the minute guard ft seta on tarsi I (vs. relatively long seta ft).

Figures

FIGURE 1. Mexecheles thailandensis sp. n., female. A—Dorsal view; B—Ventral view.

FIGURE 2. Mexecheles thailandensis sp. n., female. A–D—Legs I–IV, respectively; E—Pretarsi II in ventral view.

FIGURE 3. Mexecheles thailandensis sp. n. A—Male in dorsal view; B—Detail of male genitoanal region; C— Idiosoma of deutonymph in dorsal view.