Tetranychus (Tetranychus) truncatissimus, Naing, Htar Htar, Chandrapatya, Angsumarn, Navajas, Maria & Auger, Philippe, 2014

Naing, Htar Htar, Chandrapatya, Angsumarn, Navajas, Maria & Auger, Philippe, 2014, New species and new records of Tetranychidae (Acarina, Prostigmata) from Thailand, Zootaxa 3802 (2), pp. 257-275 : 269-272

Tetranychus (Tetranychus) truncatissimus sp. nov. Naing & Auger

( Figures 33–51 )

Type-specimens. Holotype (male), 2 males and 9 females on 12 preparations from Bambusa multiplex (Lour.) Raeusch. ex Schult. (Poaceae) , Khet Chatuchak, Bangkok, Thailand, 19/10/2010, Leg. H. H. Naing, A. Chandrapatya, P. Maneesakorn. Holotype, 1 male and 8 female paratypes deposited in the Insect museum of Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand; 1 male and 1 females deposited in the collection of CBGP, coll. Auger-Migeon N° 1825–1826, 34988 Montferrier-sur-Lez, France.

Diagnosis. This species is a Tetranychus (Tetranychus) assigned into the sixth group ( Flechtmann & Knihinicki 2002). In this group (female tarsus I with proximal pair of duplex setae in line with 3 tactile setae, one tactile setae proximal to the proximal duplex and female empodium with obvious dorsomedian spur), this species can be separated from its allied species by the shape of the male aedeagus.

Description. Male: Holotype 303 µm long, 2 males measured, (324–329) µm long (including gnathosoma).

Dorsum. Dorsal body setae long (length of holotype and variations of 3 paratypes): v 2 44 (43–47); sc 1 82 (80); sc 2 55 (56–59); c 1 62 (66); c 2 62 (66–68); c 3 57 (65–66); d 1 68 (64–69); d 2 72 (66–68); e 1 60 (60–63); e 2 58 (63–68); f 1 38 (39–46); f 2 38 (35–38); h 1 20 (19). Lobes present on dorsal striation (poorly developed in our mountings thus their shape was not recognizable).

Gnathosoma.Palptarsus terminal sensillum about 2.2 times as wide as broad, 4.5–4.6 µm long, 2–2.1 µm wide. Peritreme hooked distally.

Venter. Ventral striae without lobes.

Legs. Empodia I–IV each with obvious dorsal spur; more prominent on empodium I, smaller on empodium II and less prominent on empodia III and IV. Empodium I claw-like (uncinate), empodia II–IV each with proximoventral hairs long and free. Leg setal counts as follows:

I 2 − 1 − 10 − 5 − 9 + (4) – 13 + (3) + 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.

Aedeagus. Aedeagal shaft bent dorsad at nearly right angle. Neck very short. Aedeagal knob axis forming an angle about 40° with shaft dorsal margin. Aedeagal knob small (1.9 µm in holotype), asymmetrical, with rounded anterior projection and pointed duck-beak like posterior projection posterodorsally directed. Shallow depression present on knob dorsal margin between the two projections.

Female: 9 females measured. Idiosoma: length 407 – 500 µm including gnathosoma, width 240–295 µm.

Dorsum. Dorsal body setae lanceolate, longer than distances between bases of consecutive setae (variations of 9 paratypes): v 2 64 –71; sc 1 114–127; sc 2 79–94; c 1 97–116; c 2 92–112; c 3 90–107; d 1 95–114; d 2 96–115; e 1 88 –112; e 2 91 –115; f 1 77–97; f 2 70–83; h 1 37–46. Propodosomal striation longitudinal, hysterosomal striation transverse except between bases of e 1 and f 1 setae (longitudinal) leads to form diamond-shaped pattern between these setae.

Lobes on prodorsal striation rounded, dorsal hysterosomal striae with rounded to triangularly rounded lobes as tall as broad, wider caudally.

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

Venter. Genital flap with transverse striation. Area immediately anterior to genital flap with broken longitudinal striae. Rounded lobes present on ventral striation, broader than tall, wider medially. One pair of ventrocaudal and two pairs of pseudanal setae present.

Legs. Empodia I–IV each with obvious dorsal spur, more prominent in empodium I (about three quarters the length of proximoventral hairs), smaller in empodium II and gradually less prominent in empodia III and IV. Empodia I–IV each with proximoventral hairs long and free. Leg setal counts 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 1 tactile seta proximad to proximal duplex setae, 3 tactile setae more or less in line with proximal duplex, one solenidion at or near proximal duplex level.

Etymology. The name of the species designation is the Latin superlative of the species name of T. truncatus , meaning the most truncate.

Biological observations. Mites are located on the lower surface of the leaf. The adult females are pale yellow in colour with a pair of dark feeding spots. They produce silk and laid translucent eggs becoming yellowish with age. The males and the juvenile stages are also pale yellow.

Remarks. This new species can be easily separated from other species belonging to the 6th group of Tetranychus ( Flechtmann & Knihinicki 2002) by the shape of its aedeagus. However its aedeagus resembles those of two species that belong to the 8th group and one belonging to the 9th group: Tetranychus gloveri Banks , Tetranychus tumidus Banks and Tetranychus merganser Boudreaux respectively. Tetranychus truncatissimus is easily distinguishable from these species by: 1) its body colour, yellow vs. red or carmine, 2) the setal arrangement on the female foretarsus; 3) the size of the female empodial spurs, well developed in T. truncatissimus vs. absent, tiny or small in the above mentioned species; 4) the aedeagal knob, small, posterodorsally directed with an angle of 45° with the axis of the shaft and with a very short neck. With the exception of the tarsus setal arrangement, the body colour and the development of dorsomedian spurs, T. truncatissimus resembles to Tetranychus truncatus Ehara by the shape of its aedeagus. However, in T. truncatissimus the aedeagal hook is shorter than in T. truncatus which was already described as having a truncate hook.

Figures

FIGURES 33 – 34. Tetranychus (T.) truncatissimus sp. nov., female. 33, dorsal aspect; 34, lobes on dorsal striae.

FIGURES 35 – 39. Tetranychus (T.) truncatissimus sp. nov., male. 35, tarsus and tibia I; 36, tarsus and tibia II; 37, empodium I; 38, empodium II; 39, empodia III – IV.

FIGURES 40 – 42. Tetranychus (T.) truncatissimus sp. nov., male. 40, peritreme; 41, palptarsus; 42, aedeagi (variations).

FIGURES 43 – 47. Tetranychus (T.) truncatissimus sp. nov., female. 43, tarsus and tibia I; 44, tarsus and tibia II; 45, empodium I; 46, empodium II; 47, empodia III – IV.

FIGURES 48 – 51. Tetranychus (T.) truncatissimus sp. nov., female. 48, peritreme; 49, palptarsus; 50, flap and anterogenital area; 51, lobes on ventral striation.