Eotetranychus quercicola, Auger & Migeon, 2014

Auger, P. & Migeon, A., 2014, Three New Species Of Tetranychidae (Acari, Prostigmata) From The French Alps (South-Eastern France), Acarologia 54 (1), pp. 15-37 : 28-35

Eotetranychus quercicola n. sp.

( Figures 8-13 )

Type-specimens — Holotype (male), 7 male, 20 female and one deutonymph paratypes on 26 preparations from Quercus pubescens Willd. , ( Fagaceae ), cime de Braus (43.875°N 7.394°E, alt. 1040 m), LucØram , France, 23-VII-2009, leg. P. Auger. All the material housed in the INRA collection of the CBGP, coll. Auger-Migeon N ° 1807 for holotype and 1788- 1814 for paratypes.

Diagnosis — Dorsohysterosomal setae longer than the intervals between their bases, genital area provided with a genital flap and the area anterior to it bearing a transverse striation design. End of peritreme straight, bulbous, posteriorly enlarged. Male aedeagus long and slender, flagellate and undulate near the middle.

Description:

Male: Holotype 338 µm long (without gnathosoma), gnathosoma 92 µm long. Seven paratypes measured, 325 – 361 µm long, gnathosoma 84 – 91 µm long.

Dorsum — Dorsal body setae long, linear lanceolate, well surpassing in length distance between consecutive bases (length of holotype and variations of seven paratypes): v 1 49 (44 – 49); sc 1 (79 – 84); sc 2 55 (50 – 55); c 1 70 (66 – 72); c 2 68 (68 – 72); c 3 60 (57 – 61); d 1 60 (60 – 63); d 2 73 (64 – 74); e 1 52 (53 – 59); e 2 66 (64 – 72); f 1 47 (47 – 51); f 2 30 (28 – 39); h 1 26 (23 – 26). Dorsal striation with rounded lobes on propodosoma and hysterosoma up to third row of dorsal setae (e).

Gnathosoma — Palptarsus terminal sensillum about 3 – 3.5 as long as broad (length of holotype and variations of four paratypes): 5.6 (5 – 5.6) long 1.6 (1.6 – 1.7) wide, solenidion 3.7 (3.8 – 4) µm long, lateral eupathidia asymmetrical, ul” ζ longer than ul’ ζ: 8.7 (8.4 – 9.1) µm and 5 (4.5 – 5) µm respectively ( Fig. 10B ). Peritreme straight, bulbous distally. Distal enlargement asymmetrical, more developed posteriorly, club-shaped, varying in size and shape among and between specimens ( Fig. 10A ).

Venter — Ventral striae without lobe.

Legs — Length inferior to body length, leg I 165 (165 – 169) µm long (from trochanter to tarsus, holotype and variations of seven paratypes), leg II 148 (140 – 146), leg III 150 (142 – 154), leg IV 170 (169 – 175). Length of segments of leg I as follows ( Figs. 9A, B ): trochanter 18 (18 – 21), femur 50 (48 – 52), genu 22 (22 – 25), tibia 29 (30 – 31), tarsus 46 (42 – 45). Leg setal count as follows ( Figs. 9A,B ):

I 2 - 1 - 10 - 5 - 9 + (4) - 13 + (3) + 2 duplexes;

II 2 - 1 - 7 - 5 - 8 - 13 + (1) + 1 duplex;

III 1 - 1 - 4 - 4 - 6 - 10 + (1);

IV 1 - 1 - 4 - 4 - 7 - 10 + (1).

Tarsus I with distal duplex solenidion longer than that of proximal duplex: 49 – 56 µm and 33 – 36 µm respectively. Tactile members of distal and proximal duplexes subequal in length 10 – 12 µm and 11 – 13 µm respectively. Tarsus II sensory member of duplex 26 – 30 µm long and tactile 10 – 12 µm. Tarsus II with dorsal proximal solenidion slightly longer 13 (13.5 – 15 µm) than distance with duplex setae 12 (12 – 13 µm). Solenidia of tarsi III and IV shorter than distances to distal tactiles: length of solenidia III and IV 13.5 – 15.5 and 15 – 16 µm – distance between solenidia and tactiles 14.5 – 20 and 18 – 20 µm. Empodium I bifid each side composed of three digits, medial digit the stoutest, strong, ventral and dorsal digits slender and shorter ( Fig. 9C ). Empodia II-IV split into three pairs of hairs with proximoventral pair stronger and with ancillary setae ( Fig. 9D ). No dorsomedian spur observed.

Aedeagus — Long, slender, acutely tapering and strongly undulate near the middle, 32 (29 – 32.5) µm in length ( Fig. 10C ).

Female: 15 females measured.

Idiosoma — length 352 – 405 µm, gnathosoma 99 –

A B

C

10 µm

106 µm long, width 186 – 210 µm.

Dorsum — Dorsal body setae lanceolate, longer than distances between bases of consecutive setae ( Fig. 8A ) (variations of 15 paratypes): v 2 50 – 61; sc 1 97 – 109; sc 2 60 – 68; c 1 84 – 91; c 2 87 – 92; c 3 72 – 79; d 1 82 – 91; d 2 87 – 95; e 1 78 – 87; e 2 83 – 96; f 1 75 – 81; f 2 62 – 67; h 1 40 – 55. Distances between setae: c 1 - c 1 56 – 60, d 1 - d 1 59 – 64, e 1 - e 1 40 – 44, c 1 - d 1 43 – 51, d 1 - e 1 44 – 51. Hysterosomal striation transverse, dorsal hysterosomal striae with small lobes mostly broader than tall, rounded to triangularly rounded without oblong lobes ( Fig. 8B ). Prodorsal lobes on striation rounded and broader than tall.

Gnathosoma — Palptarsus terminal sensillum about 2 – 2.3 as long as broad, 6.6 – 6.9 µm long 3.1 – 3.3 µm wide (variations of six paratypes), solenidion 3.7 – 4.2 µm long, lateral eupathidia asymmetrical, ul” ζ longer than ul’ ζ: 9 – 9.6 µm and 5.2 – 6.2 µm respectively ( Fig. 12B ). Peritreme as in male ( Fig. 12C ).

Venter — Area immediately anterior to genital flap with transverse striae, genital flap with transverse slightly arched striae typical of willamettei - group ( Pritchard and Baker, 1955) ( Fig. 12D ). Lobes on ventral striation present laterally between third pair of ventral setae (4a) and aggenital pair (ag), rare poorly developed lobes may be present between members of 4a, anteriorly and posteriorly. Two pair of para-anal and two pairs of anal setae.

Legs — Length inferior to body length, leg I 203 – 210 µm long (from trochanter to tarsus, variations of seven paratypes), leg II 165 – 173, leg III 175 – 190, leg IV 201 – 213. Length of segments of leg I as follows: trochanter 12 – 16, femur 60 – 65, genu 25 – 31, tibia 36 – 40, tarsus 60 – 64. Leg setal count as follows ( Figs. 11A, B ):

I 2 - 1 - 10 - 5 - 9 + (1) - 14 + (1) + 2 duplexes;

II 2 - 1 - 7 - 5 - 8 - 13 + (1) + 1 duplex;

III 1 - 1 - 4 - 4 - 6 - 10 + (1);

IV 1 - 1 - 4 - 4 - 7 - 10 + (1).

Tarsus I with distal duplex solenidion longer than that of proximal duplex: 64 – 70 µm and 40 – 45 µm respectively. Tactile members of distal and proximal duplexes equal in length 13 – 15 µm. Lateral solenidion and five tactile setae proximal to proximal duplex. Tarsus II sensory member of duplex 32 – 36 µm long and tactile 11 – 14 µm. Tarsus II with proximal solenidion dorsal, longer (18 – 23 µm) than distance with duplex setae (15 – 17 µm). Tarsi III and IV solenidia subequal in length (length

of solenidia III and IV 19 – 22 and 16 – 23 µm respectively), slightly shorter than distances between their bases and those of distal tactile setae: distance between solenidia III and IV and tactile setae 21 – 26 and 21 – 27 µm respectively. Empodia I-IV split into three pairs of hairs with proximoventral pair stronger and with ancillary setae. No dorsomedian spur observed ( Fig. 12A ).

Remarks — With dorsal setae longer than the intervals between them and eight tactile setae on tibia II this species is assigned into the tiliarium group ( Pritchard and Baker, 1955), its genital area pattern corresponds to the willamettei species group ( Tuttle et al., 1976; Baker and Tuttle, 1994) and because of the shape of its aedeagus this species belongs to the carpini -species group ( Pritchard and Baker, 1955; Ehara, 1970; Baker and Tuttle, 1994). Among members of Eotetranychus from this group it can be easily distinguished by the shape of the distal peritremal enlargement: neither bent nor hooked but straight and bulbous, asymmetrical and posteriorly enlarged. Eotetranychus quercicola shares this character with only one species belonging to the carpini group: E. colurnae Mitrofanov, 1978 . However, E. quercicola can be separated from this species by several obvious characters: for example dorsal setae, duplex solenidia, legs and distances between dorsocentral setae insertions are shorter in E. colurnae (see Table I). The aeadeagus is longer in E. colurnae and male eupathidia ul’ ζ and ul” ζ are asymmetrical in male of E. quercicola only. Eotetranycus querci Reeves, 1963 , that also belongs to the carpini - species group can be found on oak and birch in the USA ( Reeves, 1963) and on Tilia japonica (Miq.) Simonk. in Japan ( Ehara, 1970). It can be easily separated from E. quercicola by the shape of its peritreme (slightly bent to almost U-shaped) and by its aedeagus which is weakly undulate near the middle.

Etymology — the species designation, quercicola , refers to the host plant on which mites were collected meaning inhabits oak.

Biological observations — Adults of this species are yellowish green in colour ( Fig. 13 ). This species lives on the under surface of the leaves, produces webbing that delimits small colonies more or less oval-shaped.

Figures

FIGURE 8: Eotetranychus quercicola n. sp., female: A – dorsal aspect; B – lobes on dorsal striation.

FIGURE 9: Eotetranychus quercicola n. sp., male: A – tarsus and tibia I; B – tarsus and tibia II; C – empodium I; D – empodia II-IV.

FIGURE 10: Eotetranychus quercicola n. sp., male: A – variations in the distal end of the peritreme (superposed peritremes belong to the same mite, juxtaposed one are variations between mites); B – palptarsus; C – aedeagi.

FIGURE 11: Eotetranychus quercicola n. sp., female: A – tarsus and tibia I; B – tarsus and tibia II.

FIGURE 12: Eotetranychus quercicola n. sp., female: A – empodia I-IV; B – palptarsus; C – distal part of the peritreme (variations between individuals); D – flap and anterogenital area.

FIGURE 13: Eotetranychus quercicola n. sp., female.