Amitus vignus Anjana et al.

M. Anjana, K. Rajmohana, D. Vimala & R. Sundararaj, 2016, On a new species of Amitus Haldeman (Hymenoptera: Platygastridae) parasitizing whitefly Zaphanera sp. (Aleyrodidae) on Vigna trilobata from India, Halteres 7, pp. 106-111 : 107-110

Amitus vignus Anjana et al. sp. n. ( Figs. 1- 11 )

urn:lsid:zoobank.org:act:8857299F-AC7E- 48D4-8FBC-EE440C669697

Diagnosis: Body length 0.81-0.87 mm (n=12); scape 4.75× as long as wide; A4 1.67× as long as wide; forewing 2.78× as long as wide; T2 1.5× as wide as long.

Description: Female: Length 0.82 mm (holotype) ( Fig. 1 ); Body black; A1-A2 yellow, clava brown; rest of the segments yellowish brown; legs except tarsi brown; tarsi yellowish brown.

Head: Head from above 1.76× as wide as long ( Fig. 3 ), hyperoccipital carina absent; vertex and occiput coarsely reticulated; eyes bare; frons not smooth, coriaceous; OOL 2.5× OD; OOL 1.25× LOL; POL 2.25× LOL; IOS 1.36× eye height and 0.6× width of head; eye height (in dorsal) 0.1× temples; head in front view with undulations (marked in Fig. 2 ), 1.24× as wide as high; scape 4.75× as wide as long, clava 3.4× as wide as long, A5 and A6 subequal, ratio of length and width of antennal segments A1-A7 and clava being: 0.19: 0.04; 0.07: 0.04; 0.04: 0.02; 0.05: 0.03; 0.05: 0.03; 0.05: 0.03; 0.05: 0.04, 0.17: 0.05 respectively ( Fig. 5 ).

Mesosoma : 1.03× as long as wide; mesoscutum reticulate with sparse setae laterally, 1.26× as long as wide; notauli complete, broader apically, than basally; upper lateral pronotal area coriaceous; mesopleura with several longitudinal lines below tegula; mesopleural depression with a deep sulcus; metapleura bare anteriorly, posteriorly with very few white seate; scutellum 1.8× as wide as long; ( Fig. 4 ). Forewing 1.2× as long as body and 2.78× as long as wide, with fine and dense microtrichia; marginal cilia 0.22× forewing width ( Fig. 8 ).

Metasoma: 1.33× as long as wide; T2 with submedial pits with fan of striae anterolaterally; 1.5× as wide as long; T3- T6 without any distinct sculpture; single setae present laterally on T3- T6; length and width of T1-T6 being: 0.06: 0.26; 0.21: 0.32; 0.03: 0.29; 0.02: 0.22; 0.02: 0.13; 0.02: 0.06 respectively ( Fig. 7 ).

Male: Similar to female except in the following characters. Body length: 0.70- 0.72 mm (n=2) ( Fig. 9 ); the ratio of the antennal segments being: 0.18: 0.04; 0.06: 0.03; 0.05: 0.03; 0.07: 0.04; 0.07: 0.03; 0.07: 0.03; 0.07: 0.04; 0.07: 0.04; 0.07: 0.07; 0.1: 0.04 respectively ( Fig. 10 ).

Variations: The females have a body size ranging from 0.81-0.87 mm and male from 0.70- 0.72 mm. Though very slight variations from the holotype were observed in the paratypes with regard to the size and proportions of antennal segments, they were rather insignificant.

Host. Amitus vignus sp. n. was reared from the parasitised puparium of Zaphanera sp. on Vigna trilobata collected on 0 6-ix-2012 from Bhiwandi, Mumbai (19.296664°N 73.063121°E; elevation 79ft). Two, five, four and three parasitoids emerged from the IV instar of the puparium ( Fig. 11 ) on the dates 0 9-0 9-2012, 10- 0 9-2012, 11-0 9-2012 and 12-0 9-2012 respectively.

Etymology: The species name ‘ vignus’ is after the generic name of the host plant.

Material examined: Holotype, ‘ INDIA: Maharashtra: Bhiwandi: Mumbai (19.296664°N 73.063121°E; elevation 79ft), 0 9-ix-2012, Coll. Vimala D, on card, Reg. No. ZSI/ WGRS /IR. INV.4982, Paratypes, 1 ♀; same data except date; 0 9-ix-2012; on card; Reg. No.ZSI/ WGRS /IR. INV.4983; 1 Ƌ; same data except Reg. No.ZSI/ WGRS /IR. INV.5171; 1 ♀; same data except Reg. No.ZSI/ WGRS /IR. INV.5172; 1 ♀; same data except date; 10-ix- 2012; Reg. No.ZSI/ WGRS /IR. INV.5173; 2 ♀; same data except Reg. No.s. ZSI/ WGRS /IR. INV.5174- 5175; 4 ♀; same data except Reg. No.s. ZSI/ WGRS /IR. INV.5176-5179; 2 ♀; same data except Reg. No.s. ZSI/ WGRS /IR. INV.5180-5181; 1 Ƌ; same data except Reg. No.s. ZSI/ WGRS /IR. INV.5182.

Comments: Most of the species of genus Amitus were erected based on the quantitative characters like antennal measurements and POL, OOL, LOL ratios, rather than qualitative ones. The Indian species A. kiefferi , A. sikkimensis and A. aleurolobi were separated mainly by the difference in the antennal measurements and dimensions of the head ( Veenakumari et al., 2014). The Oriental species, A. hesperidium Silvestri, 1927 is having head more than 2× as long as wide whereas, it is only 1.76× as wide as long in Amitus vignus sp. n. Viggiani and Mazzone in 1982, gave a key to species present in Italy and Hulden, in 1986 provided a key to species of Amitus in Finland. Amitus vignus sp.

n. when compared with the descriptions of the species outside Oriental region comes nearest to Palearctic species A. vesuvianus Viggiani and Mazzone (1982) , but can be differentiated in the following characters: occiput and vertex is very weakly reticulate in A. vesuvianus whereas, it is coarsely reticulated in the new species; also A3 is elongate, 3× as long as wide and forewing is only 2.53× as wide in A. vesuvianus , whereas A3 is only 2× as long as wide and forewing is 2.78× as long as wide in A. vignus sp. n.

The holotype of A. sikkimensis was studied by the first author. A. vignus sp. n. resembles A. sikkimensis Veenakumari and Buhl. The length to width ratio of mesosoma is same in both species and also has several transverse rugae on mesopleuron. However, both differ notably in the characters given in the key, in the measurement of the clava (clava is 3.4× as long as wide in A. vignus sp. n. whereas it is 3.75× as long as wide in A. sikkimensis ) and shape of the head (head evenly round in A. sikkimensis without undulations as in Fig. 10 ( Veenakumari et al., 2014), whereas with distinct undulations in Amitus vignus sp. n.). The POL is 2.96× LOL and OOL is 1.29× LOL in A. sikkimensis whereas POL is only 2.25× LOL and OOL 1.25× LOL in A. vignus sp. n., A. aleurolobi Mani and A. kiefferi Veenakumari and Buhl can be differentiated by the characters given in the key.

Figures

Figures 1 - 6: Amitus vignus sp. n. Female: 1. Habitus; 2. Head front (undulations marked by an arrow); 3. Head dorsal; 4. Antenna; 5. Mesosoma lateral view; 6. Mesosoma dorsal

Figures 7 - 11: 7. Metasoma dorsal; 8. Fore wing; 9 - 10. Amitus vignus Male: 9. Antenna; 10. Habitus; 11. IV instar of puparium from which parasitoid emerged.