Lasioseius kshamae, Bhattacharyya, Asit K., 2003

Bhattacharyya, Asit K., 2003, Two new species of Ascidae (Acarina: Mesostigmata) from India, Zootaxa 189, pp. 1-10 : 2-5

Lasioseius kshamae sp. nov. ( Figs. 1 ­ 8 )

Diagnosis: Dorsal shield with 43 pairs of setae, most setae tricarinate; setae z1 and s1 subequal; seven pairs of lateral setae; setae st2 and st3 nearly half as long as st1; tectum smooth; 7 rows of deutosternal denticles, four to seven teeth on each row; lateral setae on leg III tricarinate.

Female: Dorsal shield (410 m long, 254 m wide) reticulated, with forty­three pairs of setae, most setae tricarinate with serrate margin ( Fig. 1 ); anterior region with twentytwo pairs of setae; setae z1, s1 and r2 simple; setae z1 and s1 subequal in length (12 m); r3 longest (43 m) of all setae on anterior region; posterior region with twenty­one pairs (J1­5, Z1­5, S1­5; R1­6) of setae; posterior R­series captured by dorsal shield, and dispositioned along postero­lateral margin; setae J5 simple, 11 m long; setae S1, S4, S5 and Z5 borne on tubercle; setae S4, S5, Z4 and Z5 43 m, 49 m, 44 m and 61 m long respectively; seven pairs of short, simple and subequal lateral setae inserted on raised tubercles, first pair of setae on anterior region and remaining six pairs on posterior region. Peritreme visible dorsally, reaching beyond setae j1.

Tritosternum long, with paired, moderately pilose lacinae ( Fig. 2 ). Sternal shield (94 m long along midline, 117 m wide between two anterolateral corners) lineated laterally, concave posteriorly, convex anteriorly with an anteromedian depression, with three pairs of setae; setae st1 (9 m) almost half as long as st2 and st3 (subequal, 17 m); metasternal shields irregular in shape, with third pair of sternal pores and fourth pair of sternal setae; variation in the shape of metasternal shield in one paratype as depicted in fig. 3; epigynial shield posteriorly convex rather than truncate, widened behind genital setae; posterior to epigynial shield, two pairs of platelets present on ventral membrane; remnants of endopodal shields present between coxae III and IV; ventri­anal shield (137 m long, 202 m wide at their widest point) reticulated entirely, finely granulated posterolaterally, with five pairs of setae (excluding a pair of para­ and a post­anal setae); ventral membrane anterior to ventri­anal shield with paired setae; setae Jv4 tricarinate, 16 m long, on raised tubercles; metapodal shield oval, without any components. Peritreme narrow, stigma situated almost at level of anterior half of coxae IV; post­stigmatal prolongation of peritrematal shield encircling coxae IV.

Anterior margin of epistome smooth; ventrally gnathosoma with seven rows of deutosternal denticles, each row with four to seven teeth, third row widest; hypostomal setae simple; palp apotele two­tined. Fixed cheliceral digit with a row of five teeth, movable cheliceral digit with four teeth ( Fig. 4 ).

Legs I­IV 452 m, 390 m, 380 m and 380 m long (excluding ambulacra) respectively; setation of legs I­II­III­IV: genua 13­11­9­9 and tibiae 13­10­8­10; leg III with tricarinate setae laterally ( Fig. 5 ).

Male: Dorsal shield (331 m long, 229 m wide) similar in ornamentation to female dorsal shield, with forty­one pairs of setae; twenty­two pairs on anterior region, remaining setae on posterior region ( Fig. 6 ); setae r3, S4, S5, Z4 and Z5 47 m, 43 m, 38 m, 36 m and 49 m long respectively; five pairs of simple, lateral setae present, last four pairs on posterior region. Peritreme visible dorsally.

Tritosternum with long lacinae, basal part equals to half the length of lacinae. Sternitigenital shield (351 m long along midline, 90 m wide between two anterolateral corners) with five pairs of setae and a few lineation at level of st5 ( Fig. 7 ); genital aperture placed at anteromedian position; peritrematal shield free, peritreme narrow, stigma placed between coxae III and IV. Ventri­anal shield with five pairs of setae, excluding a pair of para­ and a post­anal setae.

Tectum and subcapitulum same as in female. Fixed cheliceral digit with four teeth, movable cheliceral digit tridentate.

Length (excluding ambulacra) of legs I­IV, 370 m, 305 m, 295 m and 290 m respectively; chaetotactic formulae of legs same as in female; morphological features of leg IV as depicted in fig. 8.

Types: Holotype female, Sitala, Sonarpur, West Bengal; ex. decaying date palm trunk; 22 June 2000; S.K. Bhattacharyya coll. Paratypes, twenty­nine females and two males, data same as for holotype.

Distribution: INDIA: West Bengal.

Differential diagnosis: Lasioseius kshamae most superficially resembles Lasioseius ometisimilis Westerboer, 1963 in having similar type of dorsal reticulation, same number of deutosternal rows in the hypognathal groove, almost same shape of ventri­anal shield as well as same number of setae on ventri­anal shield. However, the new species can be easily distinguished by having a greater number of dorsal setae, fewer number of lateral setae, nature of lateral setae and shorter length of lateral setae. Ventrally the new species differs from its congener species by having the following differences: shape and reticulation of sternal shield, longer length of second sternal and metasternal setae, shape of metasternal, genital and metapodal shield, presence of post­genital platelets and lack of distinct punctate areas in the posterior region of ventri­anal shield. L. kshamae also differs from L. ometisimilis in having smooth epistome and more delicate pattern of cheliceral dentition. Both species have seven rows of deutosternal denticles but instead of second row as in ometisimilis , third row is widest in new species.

Etymology: The species is named after the name of Mrs. Kshama Bhattacharyya, the wife of the author.

Figures

FIGURES 1 ­ 3. Lasioseius kshamae sp. nov., female. 1. Dorsal view; 2. Ventral view; 3. Metasternal shield in a paratype.

FIGURES 4 ­ 5. Lasioseius kshamae sp. nov., female. 4. Chelicera, 5. Leg IV.

FIGURES 6 ­ 8. Lasioseius kshamae sp. nov., male. 6. Dorsal view; 7. Ventral view; 8. Leg IV.