Tetranychus (Tetranychus) atriplexi, Auger, Philippe, Chaaban, Samah Ben, Grissa, Kaouthar Lebdi, Khoualdia, Othman & Flechtmann, Carlos H. W., 2009

Auger, Philippe, Chaaban, Samah Ben, Grissa, Kaouthar Lebdi, Khoualdia, Othman & Flechtmann, Carlos H. W., 2009, Five new species of Tetranychidae (Acarina, Prostigmata) from south Tunisian oasis areas, Zootaxa 2232, pp. 29-49 : 45-48

Tetranychus (Tetranychus) atriplexi sp. nov. Auger & Flechtmann

( Figures 57–72 )

Type-specimens. Holotype (male), 6 male and 7 female paratypes on 14 preparations from Atriplex sp., ( Chenopodiaceae ), El Hamma du Jerid, Gouvernorat de Tozeur, Tunisia, 05/06/2005, coll. P. Auger. Holotype, 4 male and 5 female paratypes deposited in the collection of the CBGP; 2 males and 2 females deposited in the type collection of the MNHN.

Diagnosis. This species is a Tetranychus sensu stricto assigned into the eighth group as defined by Flechtmann and Knihinicki (2002). Among members of Tetranychus (T.) from this group (female tarsus I with proximal pair of duplex setae distad of tactile setae; female empodium with dorsomedian spur tiny or absent), this species is distinctive by the shape of the aedeagus. The aedeagus of T. atriplexi resembles that of Tetranychus urticae Koch but the aeadeagus knob axis forms an acute angle with the axis of the shaft and its posterior projection is more differentiated from the anterior because of its duck-beak like extension.

Moreover, male empodia shape combination is also unusual in this group.

Description. Male: Holotype 356 µm long (without gnathosoma), gnathosoma 153 µm long. Five paratypes measured, 353–384 µm long, gnathosoma 139–150 µm long.

Dorsum – Dorsal body setae long, linear lanceolate, well surpassing in length distance between consecutive bases (length of holotype and variations of six paratypes): v 2 72 (68–76); sc 1 146 (126–139); sc 2 95 (90–91); c 1 122 (105–125); c 2 116 (108–113); c 3 108 (98–109); d 1 123 (86–118); d 2 119 (106–113); e 1 109 (99–110); e 2 105 (101–104); f 1 76 (72–78); f 2 71 (64–68); h 1 36 (35–39). There are no lobes on the dorsal striation.

Gnathosoma – Palptarsus terminal sensillum twice as long as broad. Peritreme hooked distally.

Venter – Ventral striae without lobe.

Legs – Empodium I bifid each side composed of two short digits, ventral pair being stronger. It also bears a strong mediodorsal spur about two-third the length of the apppendages. Empodium II also bifid with each side strongly tridigitate and carying a strong spur. Empodia III–IV with dorsal spurs less prominent and with three pairs of proximoventral hairs. Leg chaetotaxy as follows:

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

II 2 − 1 − 6 − 5 − 7 − 13 [12] + (1) + 1 duplex;

III 1 − 1 − 4 − 4 − 6 − 9+ (1);

IV 1 − 1 − 4 − 4 − 7 − 10+ (1).

Aedeagus – Aedeagal shaft bends dorsad at nearly a right angle. Knob of the aedeagus about two times the width of the stem. Its axis forms an acute angle with the axis of the shaft. Knob assymetrical with an anterior rounded projection and a more developped acute posterior projection more or less duck-beak shaped. Dorsal margin of the knob slightly convex. A small depression is present between the dorsal margin and the begining of the posterior projection.

Female: 6 females measured. Idiosoma: length 525–590 µm, gnathosoma 174–190 µm long, width 337– 414 µm.

Dorsum – Dorsal body setae lanceolate, longer than distances between bases of consecutive setae (variations of 6 paratypes): v 2 102–111; sc 1 179–196; sc 2 130–143; c 1 170–192; c 2 172–185; c 3 153–178; d 1 154–176; d 2 169–184; e 1 158–175; e 2 150–175; f 1 138–156; f 2 126–144; h 1 58–72. Hysterosomal striation transverse except between the bases of setae e 1 and f 1 (longitudinal) forming a diamond-shaped pattern between these setae. Dorsal hysterosomal striae with lobes mostly rounded but irregular in size and shape. Prodorsal lobes as tall as broad medially, lobes up to two times wider as tall laterally near sc 1 insertions. Hysterosomal lobes mostly rounded and broader than tall near setae insertions. A few triangular lobes are also present, mixed or not with rounded lobes. They are numerous in the middle of the diamond pattern but a few are also present in different parts of the hysterosoma.

Gnathosoma – Palpus with a spinneret about one and a half as long as broad. Peritreme hooked distally.

Venter – The area immediatly anterior to genital flap seems to be uniform without any punctuation. In fact, very small points longitudinaly distributed are also present in the middle part of this area. Genital flap with transverse slightly arched striae. Lobes on striation only present in the caudal part laterally. One pair of para-anal and two pairs of anal setae are present.

Legs – Empodia I–IV bear three pairs of proximoventral hairs and no spur was observed. Leg chaetotaxy as follows:

I 2 − 1 −10 − 5 − 9 + (1) − 13 + (1) + 2 duplexes;

II 2 − 1 − 6 − 5 − 7 − 13 + (1) + 1 duplex;

III 1 − 1 − 4 − 4 − 6 − 9+ (1);

IV 1 − 1 − 4 − 4 − 7 − 10+ (1).

Tarsus I with four tactile setae proximal to proximal duplex setae. Solenidion is at or near the level of the proximal duplex.

Other Material – 2 males and 7 females on 8 microscopic preparations collected on Limonium sp. ( Plumbaginaceae ), Checkmo, Gouvernorat de Tozeur, Tunisia, 05/06/2005, coll. P. Auger

Etymology. The species designation, atriplexi , derives from the generic name of the host plant on which the mites were collected.

Biological observations. Adults of this species are dark red in colour. This species also produces quite abundant webbing.

Figures

FIGURES 57, 58. Tetranychus (T.) atriplexi sp. nov., female. 57, dorsal aspect; 58, rounded and triangular lobes on dorsal striae.

FIGURES 59 – 66. Tetranychus (T.) atriplexi sp. nov., male. 59, tarsus and tibia I; 60, tarsus and tibia II; 61, aedeagi; 62, empodium II; 63, empodium I; 64, empodia III – IV; 65, distal end of peritreme; 66, palptarsus.

FIGURES 67 – 72. Tetranychus (T.) atriplexi sp. nov., female. 67, tarsus and tibia I; 68, tarsus and tibia II; 69, genital area; 70, empodia I – IV; 71, palptarsus; 72, distal end of peritreme.