Olecryptotendipes extentus, Mukherjee & Hazra, 2022

Mukherjee, Bindarika & Hazra, Niladri, 2022, First records of three genera, Cyphomella Saether, 1977, Olecryptotendipes Zorina, 2007 and Robackia Saether, 1977 of the Harnischia complex from India with description of O. extentus sp. n., O. obtunsus sp. n. and R. aequilongia sp. n. (Diptera: Chironomidae), Zootaxa 5091 (2), pp. 330-340 : 333-335

Olecryptotendipes extentus sp. n.

LSIDurn:lsid:zoobank.org:act: E4026664-59C3-49F4-8BB9-98879FE85757

Material examined. Holotype male, labelled ‘ Holotype Olecryptotendipes extentus sp. n., India, West Bengal, Burdwan [23°22ʹN, 87°85ʹE], 10.iii.2020, Coll. N. Hazra’ . Paratype 1 male, same data as holotype, labelled ‘ Paratype Olecryptotendipes extentus sp. n., India, West Bengal, Burdwan [23°22ʹN, 87°85ʹE], 25.viii.2020, Coll. N. Hazra’ . Paratype 1 male, same data as holotype, labelled ‘ Paratype Olecryptotendipes extentus sp. n., India, West Bengal, Burdwan [23°22ʹN, 87°85ʹE], 14.ix.2020, Coll. N. Hazra’ . Paratype 1 male, same data as holotype, labelled ‘ Paratype Olecryptotendipes extentus sp. n., India, West Bengal, Burdwan [23°22ʹN, 87°85ʹE], 10.xii.2020, Coll. N. Hazra’ .

Diagnosis. The adult male is distinguished from other species of Olecryptotendipes by the presence of a partially sclerotised, apicolaterally distinctly widened superior volsella with 2 apical setae and 1 subapical seta, parallel-sided anal point widest at base and small inferior volsella.

Etymology. The name ‘ extentus ’, a Latin word, refers to the apically extended or widened superior volsella.

Male (n=4). Total length 3.38–3.6, 3.49 mm. Wing length 1.92–1.95, 1.93 mm. Costal length 1.85–1.90, 1.87 mm. Antennal length 0.97–1.0, 0.98 mm.

Colouration. Thorax dark brown. Leg and abdomen yellowish brown.

Head. Head width 520–550, 530 µm. Temporal setae 10–11 (IV 3, OV 3–4, Po 4). Clypeal setae 16–17. Frontal tubercles absent. Eyes bare with dorsomedial extension of 150–160, 155 µm. Ultimate flagellomere 620–650, 635 µm long; AR 1.78–1.85, 1.81. Palpomere lengths (I–V) (µm): 30: 40–60; 50: 90–110; 100: 120–140; 130: 170–190; 180. CA 0.53–0.55, 0.54.

Thorax. Vittae present. Scutal tubercle absent. Acrostichals 8–9, dorsocentrals 8, prealars 3, supraalars 3–4, scutellars 4.

Wing ( Fig. 2A ). VR 1.12–1.14, 1.13. R 1 with 10 setae; R 4+5 bare. Brachiolum with 2 setae. Squama with 4 fringed setae. Anal lobe moderately developed.

Legs. Fore tibia with 2 setae. Mid legs with 2 tibial spurs; 25.3–27.6, 26.45 µm and 29.9 µm long with 28–30 teeth. Hind leg with 2 tibial spurs; 27.6–29.9, 28.75 µm and 34.5–36.8, 35.65 µm long with 48–52 teeth. Lengths and proportions of leg segments shown in table 2.

Hypopygium ( Figs. 2B–D ). Anal tergite band Y- shaped. Anal point parallel-sided, distally rounded, originating from caudal margin of anal tergite; 57.5–59.8, 58.65 µm long, 6.9–9.2, 8.05 µm wide at apex and 13.8–18.4, 16.1 µm wide at base. Four setae on each side of base of anal point. Transverse sternapodeme 50.6–55.2, 52.9 µm long. Superior volsella ( Fig. 2D ) curved, partially sclerotised, apicolaterally expanded and inverted T shaped, 73.6–80.5, 77.05 µm long and 11.5–13.8, 12.65 µm wide at base and 29.9–32.2, 31.05 µm wide at apex, with 2 apical setae arising from strong base and 1 subapical seta, inner part covered by microtrichia. Inferior volsella small, reaching beyond margin of anal tergite and covered with microtrichia. Gonocoxite 149.5–151.8, 150.65 µm long. Gonostylus 161–163.3, 162.15 µm long. HR 0.92–0.94, 0.93; HV 2.20–2.37, 2.28.

Distribution. West Bengal, India (present record).

Remarks. Characters such as the Y-shaped anal tergite band, distinct superior volsella, weak inferior volsella, absence of frontal tubercles and scutal tubercle affirm the placement of this new species in Olecryptotendipes Zorina. The new species is similar to O. lenzi ( Zorina, 2001) by the presence of microtrichia and the absence of a protrusion on the superior volsella. The new species resembles O. arienus Yan et Wang, 2017 in having parallel sided gonostylus, a similar number of prealar (3) and squamal (4) setae but differs in AR (1.78–1.85 of the new species while C. arienus has 1.03–1.64), HR (0.92–0.94 of new species while C. arienus has 0.46–0.49) and the shape of the superior volsella (simple, digitiform shaped in C. arienus while it is inverted T-shaped in new species).

Figures

FIGURES 2A–D. Adult male Olecryptotendipes extentus sp. n. A. Wing, B. Hypopygium, C. Hypopygium, scale 0.01 mm, D. Superior volsella, scale 0.01 mm.