Culicoides pileus, Chatterjee & Pal & Hazra, 2022

Chatterjee, Somnath, Pal, Gouri Sankar & Hazra, Niladri, 2022, Descriptions of two new species of Culicoides Latreille from Sundarbans, India with an adult key to the ornatus species group of the Oriental region (Diptera, Ceratopogonidae), Evolutionary Systematics 6 (1), pp. 89-102 : 89

Culicoides pileus sp. nov.

Figs 4A-H , 5A-E

Type material.

Holotype: male, labelled as 'Holotype Culicoides pileus Chatterjee, Pal and Hazra, India, West Bengal, South 24 Parganas, Balibazar [22°08'88"N, 88°75'72"E], 16.04.2019, Coll. S. Chatterjee’ (NZCI). Paratypes 2 males and 5 females, data as holotype (BUENTD).

Diagnosis.

Eyes bare; wing with one distal pale spot in cell r3 separated from wing margin; cell m1 with two pale spots, distal one away from wing margin; anal cell with one distal pale spot with slight medial constriction; SCo present on flagellomeres I-VII and IX-XII; parameres basally fused, cap shaped basal knob, mid portion wide, distally slender, abruptly bent laterad with pointed end.

Description. Female (n = 5). Head. Brown. Eyes bare (Fig. 5C ), separated by distance of 1-2 ommatidia; frontovertex with 33-37 SCh; antenna pale; length ratio of antennal segments (I-XIII): 12-15 (13.50): 9-10 (9.50): 10-11 (10.5): 10-11 (10.50): 10-11 (10.5): 10: 11: 10-11 (10.50): 17-19 (18): 17-19 (18): 19-21 (20): 21-22 (21.5): 29-30 (29.50); AR 1.20-1.23 (1.21); SCo (Fig. 4B ) present on antennal segments I-VII, IX-XII; maxillary palpus (Fig. 4A ) pale, hairy; length ratio of palpal segments (I-V): 8-9 (8.50): 20-25 (22.5): 25-28 (26.5): 7-9 (8): 9-10 (9.50); PR 2.15-2.27 (2.21); palpal segment III moderately swollen with subapical round shallow sensory pit with 22-26 (24) capitate sensilla restricted in sensory pit; SCh numbers in palpal segments (I-V): 0: 3: 8: 2: 6. Mandible (Fig. 5E ) with 16-17 teeth. P/H 0.85-0.89 (0.87).

Thorax (Fig. 5B ). Brown in colour.

Wing. Wing pattern as in figure 5A, costa moderately long; cell r2 moderately broad with distinct lumen, macrotrichia sparse, arranged from middle to distal most portion of wing; wing length 0.77-0.80 (0.78) mm; width 0.38-0.42 (0.40) mm; CR 0.64-0.65 (0.645). wing spots moderately distinct, second radial cell completely in dark region; pale spot over r-m cross vein moderately large, extending from vein M1 to costal margin; post stigmatic pale spot obliquely placed with slight medial constriction; cell r3 with distal large pale spot away from wing margin; cell M1 with two pale spots, distal one separated from wing margin; cell m2 with narrow pale streak connecting pale spot at basal arculus, pale spot behind medial fork and distal pale spot; distal pale spot touching wing margin; cell cua1 with moderately large, roughly round pale spot touching CuA1 vein and broadly touching wing margin; anal cell with one medially constricted distal pale spot, proximal one extended to pale spot at arculus.

Leg (Fig. 4C ). Brown in colour. Fore and mid femora pale throughout, fore and mid tibia with proximal pale region; hind femora moderately dark throughout and hind tibia also with proximal pale region; hind tibial comb with 4 spines, one nearest to spur longest, spur tip frayed (Figs 4D , 5D ).

Abdomen. Brown; two large subequal roughly rounded functional spermathecae with sclerotised necks, measuring one 46.00-50.60 (48) µm by 41.40-43.70 (42.55) µm, another one 43.70-48.30 (46.00) µm by 39.10-41.40 (40.25) µm; both with slender, moderately long neck, rudimentary third one, and faintly sclerotised ring present (Fig. 4E ).

Male (n = 3). Same as female with the usual sexual differences.

Head. Brown. Eyes bare, separated by distance of 1-2 ommatidia, frontovertex with 18-21 SCh. Palpus pale; palpal segment III moderately swollen with apical shallow sensory pit; PR 2.00.

Thorax. Dark brown.

Wing. Similar with female except distribution of macrotrichia in cells; macrotrichia sparse, mostly arranged on distal one third portion of wing; wing length 0.81-0.83 (0.82) mm, width 0.36-0.38 (0.37) mm.

Leg. Light brown in colour, hind tibial comb with 4 spines and nearest to spur longest, spur tip frayed.

Abdomen. Ninth sternum with shallow caudomedial excavation; ventral membrane not speculated; ninth tergum with lateral margin more or less straight.

Genitalia (Fig. 4H ). Apicolateral process well developed, elongated, broadly separated caudal margin between them rounded with slight mesal notch; gonocoxite (Fig. 4H ) 69.00-71.3 (70.15) µm long, 46.00-48.30 (47.15) µm wide at base, 25.30-27.60 (26.45) µm wide at apex with ventral root poorly developed and dorsal root well developed. Gonostylus 59.80-64.4(62.1) µm long; 16.10-18.40 (17.25) wide at base, 6.9 µm wide at apex slightly curved, narrowed distally with blunt mesally toothed tip. Aedeagus (Fig. 4G ) 62.10-64.40 (63.25) µm long with basal arch low, less than one sixth of total length; basal arm short and stout, directed posterolaterad; mid portion slender to moderately broad with bluntly rounded tip. Parameres (Fig. 4F ) 48.30-50.6 (49.45) µm long, fused short distance at base anteriorly, basal arm directed anterolaterad with well developed cap shaped anterior process, mid portion wide, distally slender, abruptly bent laterad with pointed end.

Remarks.

New species shows similarities with C. aequalispinus in bare eyes and mandibular teeth number but differs in attributes like distribution of SCo on antennal segments, and presence of two equal length spines nearest to the spur in C. aequalispinus . The new species shares a few similarities with C. peliliouensis Tokunaga in Tokunaga and Esaki 1936 like bare eyes, disposition of some pale spots on wing but differs in characters like distribution of SCo on antennal segments (SCo present on I, V-VII and IX-XII in C. peliliouensis but in C. pileus sp. nov. these are on I-VII and IX-XII), pale spot on cell r3 broadly touching the wing margin but in new species it is separated by dark region; pale spot over r-m cross vein is different in shape, post stigmatic pale spot medially constricted in C. pileus but not in C. peliliouensis . Culicoides pileus shows some similarities with C. circumbasalis Tokunaga, 1959 and C. ornatus Taylor, 1913 but differs in characters like distal pale spot in anal cell of wing (two separate distal pale spots present in both C. circumbasalis and C. ornatus but in C. pileus a single pale spot present with little medially constricted), cell r3 with three pale spots and most distal one touching the wing margin in C. circumbasalis but two in C. pileus sp. nov. and most distal one away from the wing margin. It is quite similar in some attributes with C. cordiger Macfie, 1934 but differs in distribution of SCo on antennal segments (SCo are present on antennal segments I-XIII in C. cordiger ) and mandibular teeth number (7-12 in C. cordiger but 16-17 in C. pileus ). Culicoides pileus differs from C. damnosus Delfinado, 1961 and C. quatei Wirth & Hubert, 1989 in the shape of pale spot over r-m cross vein and distribution of SCo on antennal segments. It shares similarities with C. mcdowelli Delfinado, 1961 but differs in the shape of pale spot over r-m cross vein, distal pale spot on cell r3 (touching the wing margin in C. mcdowelli ) and mandibular teeth number (11-13 in C. mcdowelli ). It also shows some similarities with C. hollandiensis Tokunaga, 1959 in wing pattern but pale spot is absent at the base of CuA1 in C. pileus and anal cell with two separated distal pale spots in C. hollandiensis . Culicoides pileus differs from C. hollandiensis in pale marking of wing (anal cell with two separate distal pale spots in C. hollandiensis ) and shape of the aedeagus. Culicoides pileus differs from C. pampangensis Delfinado, 1961 in structure of paramere and pale marking of wing (cell r3 with distal pale spot not prominent in C. pampangensis Delfinado). Culicoides paragarciai Dyce, 1996 differs from C. pileus in pale marking on wing (pale marking absent in C. paragarciai ) and structure of hind tibial comb (hind tibial comb with 5 spines and 2nd from the spur is longest in C. paragarciai whereas 4 spines and 1st from the spur longest in C. cornatus ).

Etymology.

The name ' Culicoides pileus ' refers to Latinised version of cap shaped basal knob of parameres.

Distribution and bionomics.

The species was collected from Sundarbans Mangrove Forest in India (West Bengal state). Adult midges were collected from a cowshed using an ultraviolet light trap in the type locality situated in the vicinity of Datta River. The type locality is at an altitude of 7.50 m above sea level.

Figures

Figures 4. A-H. Adult male and female of Culicoides pileus sp. nov. A. Female maxillary palp; B. Female antenna; C. Female legs (femur and tibia); D. Female hind tibial comb; E. Female spermatheca; F. Paramere of male genitalia; G. Aedeagus of male genitalia; H. Male genitalia. Scale bar: 0.05 mm.

Figures 5. A-E. Adult male and female of Culicoides pileus sp. nov. A. Female wing (Photograph); B. Female thorax (Photograph); C. Female Eye (SEM Photograph); D. Female hind tibial comb (SEM Photograph); E. Female mandible (SEM Photograph).