Euseius tripuraensis, Kar & Karmakar, 2022

Kar, Anamika & Karmakar, Krishna, 2022, Seven new species of phytoseiid mites (Acari: Mesostigmata) from Tripura, northeastern India, Zootaxa 5120 (2), pp. 213-241 : 214-217

Euseius tripuraensis sp.nov.

( Figs 1–5 , 36–40 )

Female (n=13)

Diagnosis. The new species is characterised by having dorsum mostly smooth, striated laterally with prominent sigilla; peritreme extends between z2 and j3, all ventral shields smooth, fixed digit of chelicerae with five teeth clubbed anteriorly and a distinct pilus dentilis, spermatheca unique, proximal part of calyx short and tubular with prominent atrium, distal part funnel shaped, leg IV with three macrosetae with pointed tips.

Dorsum ( Fig. 1 ). Dorsal shield 325 (322–330) long and 218 (215–222) wide, smooth, anteriorly striated with sigilla mostly on prodorsal area, prodorsum wide with six pairs of solenostomes (gd2, gd4, gd5, gd6, gd8 and gd9); 17 pairs of setae on dorsal shield and two pairs of setae on unsclerotised cuticle: j1 32 (30–33), j3 16 (14–18), j4 7 (5–8), j5 7 (5–8), j6 7 (5–8), J2 8 (7–10), J5 4 (3–5), z2 11 (10–12), z4 7 (5–8), z5 7 (5–7), Z1 8 (6–9), Z4 9 (8–12), Z5 52 (50–53), s4 13 (12–15), S2 12 (10–13), S4 13 (10–14), S5 14 (12–15), r3 11 (10–12), R1 8 (6–9). All setae smooth, setae j1, j3 and Z5 long, seta Z5 longest, all other setae medium to small.

Sources of measurements: Original paper; Evans, 1953; Ehara and Bhandhufalck, 1977; Kolodochka, 1988; Schicha and Corpuz–Raros, 1992 ‘–’: not available

Peritreme ( Fig. 1 ). Extending to level between bases of z2 and j3.

Venter ( Fig. 2 ). Sternal shield square shaped, posterior margin of sternal shield with indistinct loop and forms a groove at the lateral part of the posterior margin of sternal shield. Sternal shield 58 (56–59) long and 73 (71–74) wide at level of setae st1–st3 and st3–st3 respectively, with three pairs of setae and two pairs of poroids; one pair of setae (st4) 28 (27–30) long and conspicuous poroid on distinct metasternal plate. Distances between st2–st2 65 (62–66), st5–st5 72 (70–73). Two pairs of metapodal platelets present. Primary metapodal platelet 9 (8–11) long and 3 (2–4) wide, secondary metapodal platelet 5 (3–6). Genital shield smooth, broad at base and narrow at genital opening with irregular circular flap touching sternal loop anteriorly. Ventrianal shield, smooth, semi-rounded, ZV2 at the lateral margin of ventrianal shield, 93 (92–95) long, 51 (50–54) wide at level of ZV2 and 76 (74–77) wide at anus level with three pairs of pre-anal setae, JV1 15 (14–16), JV2 15 (14–16), ZV2 15 (14–16) and one pair of large elliptical pre-anal pores gv3 just below JV2, 33 (31–33) apart. Membrane surrounding ventrianal shield with four pairs of setae ZV1 20 (18–21), ZV3 8 (8–10), JV4 8 (8–10) and JV5 25 (24–26); seta JV5 long and smooth.

Chelicera ( Fig. 3 ). Fixed digit 26 (25–27) long with five teeth clubbed anteriorly and distinct pilus dentilis, movable digit 24 (23–25) long with two teeth.

Spermatheca ( Fig. 4 ). Calyx widened at the ends 12 (11–13) long. Proximal part of calyx short and tubular with prominent atrium, while the distal part of calyx funnel shaped, minor duct and major duct clearly visible.

Leg ( Fig. 5 ). The genu, tibia and tarsus of leg IV with pointed macrosetae of following lengths: genu 35 (34– 36), tibia 32 (31–34) and tarsus 52 (50–53). Chaetotactic formula of genu II 1 2/1 1/1 1 and genu III 1 2/1 2/0 1. Length of leg I 350 (346–352), leg II 255 (252–258), leg III 262 (258–264) and leg IV 372 (368–374). Leg III with macrosetae on genu 27 (25–27) long, tibia 28 (26–29).

Type specimens. Holotype: female (Acarol.lab/ BCKV/8577 /2021) collected from Gulmohar tree ( Delonix regia ), at Hezamara: 23°29'50"N, 91°25'32"E, 30m AMSL, West Tripura, on 28 th August , 2019 and deposited in the NZC, Zoological Survey of India, Kolkata ; 6 paratype females (Acarol.lab/ BCKV/8578–89 /2021) collected from same host with same collection data as holotype; 6 paratype specimens (Acarol.lab/ BCKV/8683–8686 /2021) from Loktak , Manipur on 2 nd September , 2019 from the same host and deposited in the Acarological laboratory, Department of Entomology , BCKV, Mohanpur, Nadia, West Bengal, India.

Etymology. The specific name ‘ tripuraensis ’ refers to the type locality Tripura, where the species was collected.

Remarks. The new species is different from all the species of genus Euseius by having its unique type of ventrianal shield and spermatheca. The new species is also different from all Euseius spp. described and reported from India ( Kar & Karmakar, 2021b), and close to E. ovalis ( Evans, 1953) ; but the distal part of the calyx of the new species is much wider than the distal part of clayx of E. ovalis . However, this new species is very close to Euseius ovalis ( Evans, 1953) ; E. aizawai ( Ehara & Bhandhufalck, 1977) ; E. ghilarovi Kolodochka, 1988 ; and E. wyeno ( Schicha & Corpuz-Raros, 1992) by having a very similar type of spermatheca. It also differes from these close species by the dorsal setal length, shape of ventrianal shield, shape of macrosetae on leg IV and shape of spermatheca. All the differences between the new species and its close species are presented in Table 1 .

Figures

FIGURES 1–5. Euseius tripuraensis (female). 1. Dorsal view of idiosoma; 2. Ventral view of idiosoma; 3. Chelicera; 4. Spermatheca; 5. Genu, tibia and basitarsus of leg IV.

FIGURES 36–44. 36–40. Euseius tripuraensis (female). 36. Dorsal view of idiosoma; 37. Ventral view with ventrianal shield; 38. Spermatheca; 39. Genu, tibia and basitarsus of leg IV; 40. Chelicera; 41–44. Euseius spontanieum (female). 41. Dorsal view of idiosoma; 42. Genu, tibia and basitarsus of leg IV; 43. Chelicera; 44. Spermatheca.