Dasyhelea (Sebessia) folia, 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 (Sebessia) folia sp. nov.

Type material.

Holotype ♂, India, West Bengal, South 24 Parganas, Pakhiralaya [22°08'13.0"N, 88°49'45.1"E], 25.V.2018, Coll. S. Brahma.

Diagnosis.

The only species in the subgenus Dasyhelea Sebessia bearing a distinct oval shaped gonocoxite; one long seta near base of gonostylus; broad and leaf like basal arms of parameres; apicolateral process with one long seta at subapical notch.

Description.

Male adult (n = 1) (Figs 7A-J , 8E ). Total body length 2.1 mm.

Head. Light brown in colour. Eyes separated by about a diameter of an ommatidium. Frontal sclerite (Fig. 7A ) 55 μm long, 30 μm wide, oval shaped. Flagellum (Fig. 7B ) 0.6 mm long; flagellomere XIII without any prominent apical projection; length ratio of flagellomeres (I-XIII): 23: 13: 12: 12: 12: 13: 13: 13: 13: 30: 22: 20: 34; AR 1.07; flagellomeres X-XIII with sensilla basiconica. Clypeus as in figure 7C, with 3 pairs of setae. Palpus (Fig. 7D ) pale brown; length ratio of palp segments (I-V): 10: 10: 16: 11: 12; PR 2.3; palp segment III with 1 capitate sensillum at its mid length.

Thorax. Yellowish in colour.

Wing (Fig. 7E ). Wing margin with short, prominent macrotrichia, macrotrichia in wing surface sparse. WL 0.91 mm long, WW 0.33 mm; CR 0.5. FCu proximal to costal extremity.

Legs (Fig. 7F ). Pale brown in colour. Hind tibial comb (Fig. 7G ) with 7 spines, third one longest. TRI 3.0, TRII 2.2 and TRIII 3.0.

Abdomen. Light brown in colour.

Genitalia (Fig. 7H , 8E ). Tergite 9 broad apically, inverted dome shaped, 115 μm long and 133.5 μm wide. Apicolateral processes (Fig. 7I ) 27.5 μm long, base 7 μm wide and apex 2.3 μm wide, a distinct notch at about mid length from base bearing one long seta; cercus bare. Sternite 9 (Fig. 7H ) 1.93 × wider than length with bifurcated posteromedian margin. Gonocoxite oval shaped, 78 μm long, greatest width 48 μm, having 3-4 stout, long setae on dorsal side. Gonostylus stumpy, 47 μm long, 16 μm wide basally and 4.5 μm wide apically; less sclerotisation up to mid length; somewhat abruptly narrowed at about three fourth length from base; a single, distinct, dorsal, long seta present near base followed by another one, ventrally 4 small setae at middle region and one long seta at basal region. Each basal arm of parameres (Fig. 7H ) 34.5 μm long, broad and leaf like, joined moderately with 30 μm long posteromedian projection, extended beyond mid gonocoxite. Aedeagus (Fig. 7J ) “H” shaped, 32 μm long, 43.5 μm wide; basal arm 18.5 μm long enclosing 26.5 μm wide basal arch; posterolateral arm 9 μm long, stout; ventromedian projection absent.

Female adult. Unknown.

Pupa and larva. Unknown.

Etymology.

The name, " Dasyhelea folia " derived from Latinised version of leaf, referring to somewhat leaf shaped basal arms of parameres of male genitalia.

Remarks.

Dasyhelea (Sebessia) folia sp. nov. shows similarities with D. dellapei Díaz, Spinelli & Ronderos, 2010 (Argentina), D. fueguina Díaz, Spinelli & Ronderos, 2010 (Argentina) and D. patagonica Ingram & Macfie, 1931 (Argentina, and Chile) in the shape of the basal arms of parameres, but the overall structure of parameres, gonostylus and aedeagus are markedly apart. Dasyhelea folia has similarities with D. (S.) holosericea (Meigen, 1804) (Estonia, Finland, Poland, Lithuania, France, and Russia) in a similar shaped aedeagus and gonostylus, but the parameres, the apicolateral process and the gonocoxite are different. The new species is similar to D. huertai Grogan, Diaz, Spinelli & Ronderos, 2016 (France) and D. turnbowi Grogan, Diaz, Spinelli & Ronderos, 2016 (France) in respect to the parameres, but the venation pattern of the wing, the shape of tergite 9, the gonocoxite and gonostylus are opposing. The combination of characters stated in the diagnosis justifies D. (Sebessia) folia as a new member of this subgenus.

Distribution.

The material was collected from the Deltaic Proper of Gangetic West Bengal, at an altitude of 8 meters above sea level - new species from India.

Ecological notes.

Adults of Dasyhelea (S.) folia sp. nov. were captured in proximity of a flower garden adjoining a brackish water river (Fig. 2E ), when the air temperature was 33-35 °C and the relative humidity was 80-82%.

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 7. A-J Adult male of Dasyhelea (Sebessia) folia sp. nov. A Frontal sclerite; B Flagellum; C Clypeus; D Palpus; E Thorax; F Femora and tibiae (right to left) of fore, mid and hind legs; G Hind tibial comb; H Genitalia (left dorsal and right ventral view); I Apicolateral process; J 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.