Dacus (Mellesis) nagarathnae Abhishek, David & Hancock, 2024

Abhishek, Venkateshaiah, David, Karamankodu Jacob, Hancock, David Lawrence, Pradeep, Shivanand, Kalleshwaraswamy, C. M., Sridhara, S. & Satish, K. M., 2024, New Indian species of Dacus Fabricius (Diptera: Tephritidae: Dacinae: Dacini) similar to Dacus crabroniformis (Bezzi), endemic to the Western Ghats and Northeastern Himalayas, Zootaxa 5446 (3), pp. 366-382 : 373-375

Dacus (Mellesis) nagarathnae Abhishek, David & Hancock , sp. nov.

( Figures 46‒55 )

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Description: Male

Head ( Fig. 48 ): Frons 0.64 mm high and 0.66 mm wide, fulvous with two frontal setae and single orbital seta, bases of all setae black, ocellar triangle black, ocellus fuscous, outer vertical seta and medial vertical seta well developed; occiput black except posterior margin of eye and vertex, postocular setae thin, black; face entirely black leaving triangular fulvous markings towards extremes of epistomal margin; lunule fulvous; antennal segments dark fuscous, arista not plumose, combined length of antennal segments viz., scape (0.468 mm), pedicel (0.498 mm) and flagellomere (1.269 mm) longer than the vertical length (1.22 mm) of face.

Thorax ( Figs 49, 50 ): Scutum black without lateral and medial postsutural yellow vittae. Orange-red markings as follows: notopleuron, postpronotal lobe, base of transverse suture, narrow anepisternal stripe, slightly broader than notopleuron, continued as orange-red spot on katepisternum, 0.6 of katatergite and anatergite. Scutellum orange red with a narrow black, basal band and a pair of apical scutellar setae. Chaetotaxy; 2 scapular setae, 1 anterior notopleural seta, 1 posterior notopleural seta, 1 anepisternal seta, 1 post-alar seta, 1 intra-alar seta. 1 postsutural supra-alar seta.

Legs ( Fig. 47 ): Coxa, trochanter, femur, tibia of fore and mid legs fully dark fuscous, 0.2 of hind femur fulvous basally and remainder fuscous; hind tibia fuscous; all tarsal segments fulvous.

Wing ( Fig. 52 ): (5.66 mm) predominantly hyaline with broad costal band confluent with vein R 4+5 spilling over to cell r 4+5 at or before the level of end of vein R 2+3, extension of cell cup longer than cup, anal streak absent.

Abdomen ( Fig. 51 ): Elongate (2.63 mm long, 1.62 mm wide), petiolate, tergites black; tergite I with single fulvous transverse band, tergites II and III predominantly black with dense hair, tergite IV and V black except for dense white hair along medial longitudinal region. Pecten present on tergite III; sternite V with shallow/ flat posterior emargination, all sternites dark brown in colour.

Male genitalia ( Figs 53, 54, 55 ): Epandrium strongly sclerotized, longer (0.24 mm) and broader (0.29 mm) than length of lateral surstylus; posterior lobe (0.11 mm) of lateral surstylus elongate, 5‒6 times longer than anterior lobe (0.02 mm). Proctiger membraneous (0.12 mm), round and smaller than epandrium. Epandrium and surstyli distinctly bulb-shaped in posterior view; medial surstylus (0.02 mm) shorter than lateral surstylus (0.1 mm), tapering towards apex with a pair of thick prensisetae. Phallus elongate (2. 93 mm) with well-developed glans (0.56 mm); 0.75 of glans sclerotized with patterned praeputium; subapical lobe and basal lobe present.

Attractant: Zingerone.

Host plant: Not known.

Material examined: Holotype ♂, INDIA: Meghalaya, Ri Bhoi, Bhoirymbong , 03.xii.2023, Abhishek, V. ( NIM)

Etymology: This species is named after Nagarathna, senior author’s mother.

Remarks: Dacus nagarathnae , sp. nov., is similar to D. satanas (Hering) , D. maculipterus White and D. crabroniformis (Bezzi) in possessing a black face and a broad costal band confluent with vein R 4+5 except at apex. It can be differentiated from D. satanas by the narrower anepisternal stripe as broad as notopleuron and dark fuscous postpronotal lobes; from D. maculipterus by narrower transverse suture markings and predominantly black hind femur; from D. crabroniformis by the orange-red colour of postpronotal lobes, scutellum and transverse suture markings and predominantly fuscous (0.80) hind femora.

Figures

FIGURES 46−47. Dacus nagarathnae Abhishek, David & Hancock, sp.nov. 46, dorsal habitus; 47, lateral habitus.

FIGURES 48−55. Dacus (Mellesis) nagarathnae Abhishek, David & Hancock, sp. nov. 48, head; 49, scutum (dorsal view); 50, thorax (lateral view); 51, abdomen; 52, wing; 53, epandrium and surstyli (lateral view); 54, epandrium and surstyli (posterior view); 55, glans of phallus.