Dasyhelea (Dasyhelea) quasifulcillata, Brahma & Chatterjee & Hazra, 2023

Brahma, Shubhranil, Chatterjee, Somnath & Hazra, Niladri, 2023, Five new Indian species of the genus Dasyhelea Kieffer (Diptera, Ceratopogonidae) with a key to the adult males, Evolutionary Systematics 7 (1), pp. 51-66 : 51

Dasyhelea (Dasyhelea) quasifulcillata sp. nov.

Type material.

Holotype ♂, India, West Bengal, Purba Bardhaman, Burdwan [23°15'03.8"N, 87°50'45.1"E], 11.IV.2017, Coll. S. Brahma. Paratypes: 2♂♂, data same as before, except 20.IV.2018; 2♂♂, India, West Bengal, Birbhum, Narayanpur [24°14'40.6"N, 87°41'30.7"E], 8.II.2017, Coll. S. Chatterjee.

Diagnosis.

The only species in the subgenus Dasyhelea Dasyhelea diagnosed by a vertical unsclerotised region in frontal sclerite; gonocoxite with two long apical setae ventrally; posteromedian projection of parameres broad, blade like; posterolateral arm of aedeagus with flap like extensions inwardly directed.

Description.

Male adult (n = 5) (Figs 4A-K , 8B ). Total body length 1.8-1.9 (1.85) mm.

Head. Dark brown in colour. Eyes separated by one fourth of diameter of an ommatidium. Frontal sclerite (Fig. 4A ) 57-58 (57.5) μm long and 54-56 (55) μm wide, hyperbolic, evenly sclerotised, except mid vertical line, with a minute apical projection. Antennal flagellum (Fig. 4B ) pale brown, 0.50-0.6 (0.55) mm long; XIII with a distinct apical projection; length ratio of flagellomeres (I-XIII): 18 (18): 11-13 (12): 11-13 (12): 11-13 (12): 11 (11): 12 (12): 12 (12): 12 (12): 12 (12): 24-25 (24.5): 23 (23): 18-19 (18.5): 35-36 (35.5); AR 1.00 (1.00); flagellomeres II-XIII with sensilla basiconica. Clypeus (Fig. 4C ) with 4 pairs of setae. Palpus (Fig. 4D ) pale; length ratio of palp segments (I-V): 9 (9): 11-12 (11.5): 20 (20): 12 (12): 14-15 (14.5); PR 2.2 (2.2); palp segment III with 2 capitate sensilla at lower half region.

Thorax (Fig. 4E ). Brown in colour without any prominent infuscation. Acrostichals with 9-10 pairs, irregularly biserial; dorsocentrals 8-9 pairs, irregularly biserial; prealars 7, uniseral; scutellum with 5 setae.

Wing (Fig. 4F ). Wing margin with short, prominent macrotrichia; r5 with macrotrichia at anterior region. WL 0.90 (0.90) mm, WW 0.30-0.32 (0.31) mm, CR 0.45 (0.45). Cubital fork present before costal extremity.

Legs (Fig. 4G ). Pale in colour, mid region of fore, mid and hind femora, and fore and mid tibiae prominently infuscated, hind tibia with diffused infuscation. Hind tibial comb (Fig. 4H ) with 8 spines. TRI 2.83-3.16 (3.01), TRII 2.85-3.45 (3.14) and TRIII 2.61-3.00 (2.73).

Abdomen. Brown in colour.

Genitalia (Figs 4I , 8B ). Tergite 9 broad apically, inverted dome shaped, 120-122 (121) μm long and 224-225 (224.5) μm wide anteriorly, 50-51 (50.5) μm wide posteriorly. Apicolateral processes (Fig. 4J ) 11-12 (11.5) μm long with one prominent apical seta, cercus setose with median sized setae. Sternite 9 4.81 × wider than length, with a middle concave excavation. Gonocoxite stout, elongated, 89-90 (89.5) μm long, greatest width 55 (55) μm. Gonostylus long, gradually tapering, 82-83.5 (83) μm in length, 18-19 (18.5) μm wide basally and 6 (6) μm wide apically; one distinct seta at mid length, distal one fifth region containing two prominent stout setae, subapex bearing 2 setae dorsally and one seta ventrally. Parameres thin, highly sclerotised (Fig. 4I ) with left basal arm 78-79 (78.5) μm long, joined moderately with posteromedian projection; right basal arm 53-54 (53.5) μm long; posteromedian projection 107-108 (107.5) μm long, 25-26 (25.5) μm wide medially, bladelike, moderately sclerotised, terminating in a point beyond gonocoxite-gonostylus junction. Aedeagus (Fig. 4K ) broad, 69 (69) μm long, 82-83 (82.5) μm wide, basal arm 32-33 (32.5) μm long, highly sclerotised, directed laterad; basal arch 44-45 (44.5) μm long; posterolateral arm 46 (46) μm long, stout with flaplike inward projection.

Female adult. Unknown.

Pupa and Larva. Unknown.

Etymology.

The name " Dasyhelea quasifulcillata " refers to its close similarity with allied species, D. (Dasyhelea) fulcillata Yu, 2005.

Remarks.

The new species resembles Dasyhelea (Dasyhelea) fulcillata Yu in Yu et al. 2005 (China) in the shape of the both basal arms of parameres, posteromedian projection of parameres and basal arm of aedeagus, but it differs in the margin of sternite 9, the apex of gonostylus, the absence of prominent seta at about mid length of gonostylus, basal arch and apex of posterolateral arm of the aedeagus. Dasyhelea (D.) neofusca Yu in Yu et al. 2005 (China) also has similar shaped parameres and margin of sternite 9, but the structure of the apicolateral process, the gonostylus and the aedeagus are contrasting. Dasyhelea bilineata Goetghebuer, 1920 (Belgium, Russia, Norway, Finland, Estonia, Great Britain, Ireland, Hungary, Germany, Poland, Czech Republic, Slovakia, Switzerland, Austria, France, Croatia, Italy, Romania, Ukraine, Spain, Turkey, Gibraltar, Bulgaria, and Algeria) bears little similarity with D. (D.) quasifulcillata sp. nov. in overall structure of the gonocoxite and aedeagus, while the basal arm of the aedeagus and the shape of the parameres differ from each other. The present species shares resemblances with D. (D.) flavifrons ( Guérin-Méneville, 1833) (France, Belgium, Estonia, Germany, Poland, Great Britain, Czech Republic, Switzerland, Austria, Croatia, Spain, Bulgaria, Greece, Russia, Ukraine, and USA) in parameres, but apical portion of gonostylus, basal arms, and basal arch of the aedeagus markedly differ. Dasyhelea (D.) malleola Remm, 1962 (Estonia, Spain, Andorra, Poland, Germany, Czech Republic, Ukraine, and Algeria) has identical basal arms of the parameres, but the posteromedian projection of the parameres, apex of the gonostylus and posterolateral arm of the aedeagus are opposing with those of D. quasifulcillata . However, the combination of characters provided in the diagnosis validates D. (D.) quasifulcillata as a new member of this subgenus.

Distribution.

The specimens were collected from the Deltaic Proper of Gangetic West Bengal at an altitude 30-42 meters above sea level - new species from India.

Ecological notes.

Dasyhelea (D.) quasifulcillata sp. nov. adults were captured around shrub vegetation and paddy field area adjoining a freshwater river (Fig. 2B ) when the air temperature was 27-35 °C and relative humidity was 70-75%.

Figures

Figure 2. A-E Photographs of collection sites where light traps were operated. A Collection site of Dasyhelea (Dasyhelea) incisura sp. nov.; B Collection site of Dasyhelea (D.) quasifulcillata sp. nov.; C Collection site of Dasyhelea (D.) trigona sp. nov. (adjacent fresh water river shown as different image at upper right corner); D Collection site of Dasyhelea (Sebessia) falxa sp. nov.; E. Collection site of Dasyhelea (S.) folia sp. nov. (adjacent brackish water river is same for both D and E, shown as different image at upper middle).

Figure 4. A-K Adult male of Dasyhelea (Dasyhelea) quasifulcillata sp. nov. A Frontal sclerite; B Flagellum; C Clypeus; D Palpus; E Thorax; F Wing; G Femora and tibiae (right to left) of fore, mid and hind legs; H Hind tibial comb; I Genitalia (left dorsal and right ventral view); J Apicolateral process; K Aedeagus. Scale bars: 0.05 mm.

Figure 8. A-E Adult male genitalia structures. A Dasyhelea (Dasyhelea) incisura sp. nov.; B Dasyhelea (Dasyhelea) quasifulcillata sp. nov.; C Dasyhelea (Dasyhelea) trigona sp. nov.; D Dasyhelea (Sebessia) falxa sp. nov.; E Dasyhelea (Sebessia) folia sp. nov. Scale bars: 0.05 mm.