Nilotanypus ctenochelus Cranston & Krosch & Tang 2022, new species
Creators: name: Cranston, Peter S.
name: Krosch, Matt N.
name: Tang, Hongqu
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Chironomidae
Nilotanypus
Nilotanypus ctenochelus

description: Nilotanypus ctenochelus new species
http://zoobank.org/ 139262E4-37D0-4487-BC82- 093A9A05FBD7
Type material: Holotype: Australia, P ♂, slide mounted in Euparal, Queensland, Paluma, Birthday Ck., 18°59’S 146°10’E, 650 m a.s.l., 25–26. iii.1989, leg. Cranston, deposited ANIC. Paratypes, P ♂, 2P ♀, on same slide as holotype, same data.
Other material examined: Australia, Northern Territory. Kakadu N.P., Pe, Djalkmara Billabong, 12°40’S 132°56’E, 10.iv.1989; 9Pe, Rockhole Mine Ck., 13°30’S 132°30’E, 1.iv.1993, 8.v.1993, leg. Smith; same except P ♂, P ♀, [on same slide as Pe, N. haplochelus] 13.v.1993; Pe, Koolpin Ck., 13°29’S 132°35’E, 15–16.v.1992. Queensland, Daintree N.P., Pe, Noah Ck., 16°08’28”S 145°25’37”E, 2–3.x.2016, leg. Krosch & Cranston; 3Pe, Oliver Ck., 16°08’S 145°26’E, 9–10.ix.1998; Mt Windsor N.P., 16°15’11”S 145°2’24”E, 6.x.2016, leg. Krosch, Bryant & Cranston; Pe, Mt. Lewis N.P., Windmill Ck., 8–9.ix.1997, leg. McKie; Pe, nr Mareeba, Davies Ck., 17°01’S 145°35’E, 27–28.viii.1997 [same slide includes Pe, N. haplochelus]; L, Mt. Hypipamee N.P., Wondecla Ck. [=Nigger Ck.,] 17°27’S 145°29’E, 11.x.2016, leg. Krosch & Cranston; (MV) FNQ16NIG15; L, same except 29.viii.2012, leg. Cranston; Pe, Tully Gorge N.P., Pixies Ck., 2–3.ix.1997, 17°47’S 145°41’E, leg. McKie; Pe, Palmerston N.P., Learmouth Ck., 650 m a.s.l., 17°35’S 145°42’E, 8–9.iv.1997, 3L, Koombooloomba N.P., Koombooloomba Ck., nr dam, 17°50’16”S 145°35’16’E, 12.x.2018, leg. Krosch & Bryant; (MV) FNQ16RAV1.4, 1.5; 2 Pe, Yuccabine Ck., 18°11’07”S 145°46’00”E, 9.vi.1997, leg. McKie; 2Pe, Yuccabine Ck., 10.vi.1997, leg. McKie; 2P ♂, 2P ♀, Paluma, Birthday Ck., 18°59’S 146°10’E, 650 m a.s.l., 25–26. iii.1989; 3L, same except 1.x.2009, leg. Krosch; L, same except 31.viii.2005, leg. Cranston; 2L, Camp Ck., 18°58’S 146°09’E, 21.ix.2008, leg. Krosch & Bryant; L, Cooloola N.P., Franki’s Gulch, 26°03’S 153°04’E, 6.iv.1996; 3L, Tamborine Mt., Cedar Ck., 27°54’S 153°11’E, 26.ix.1989. New South Wales. 2L, Bungonia, Bungonia Falls, 34°47’S 150°00’E, 11.xi.1988; 2 Pe, Currowan S.F., Cabbage Tree Ck., 35°34’S 150°02’E; 2 Pe [same slide includes 1Pe N. haplochelus] Brindabella, Goodradigbee R., 35°23’54”S 148°44’51”E, 4.i.2001; 7 Pe, above Captains Flat, Molonglo R., 35°35’S 149°28’E, 6.iii.1993; Pe, nr. Mongarlowe, Mongarlowe R., 35°24’S 149°57’E, 17.iii.1993; L., Kosciuszko N.P., Leather Barrel Ck., 36°31’S 148°11’E, 4.xii.2010. Victoria, Pe, Buckland R., 36°48’S 146°51’E, 1.vii.1991, leg. Cook; 2L, Tambo R., south branch, 12.xii.1990, 36°59’S 147°51’E, leg. Hortle.
Etymology: From Greek, cteno = comb, chelus = claw, recognising the comb-like larval posterior parapod claw.
Diagnostic characters
The two new Australian species described here conform in all stages to Nilotanypus, with additional features noted above in an expanded generic diagnosis. Male adults may be separable by the tarsal pseudospurs: N. haplochelus sp. n. has a subapical pseudospur on fore tarsomere on the foreleg (P 1), whereas N. ctenochelus sp. n, lacks pseudospurs on Ta 1 of P 1. Midleg pseudospurs may distinguish but confirmation based on teneral specimens is unsafe. The gonostylus of the male genitalia can separate: N. ctenochelus sp. n. has few (2–3) setae and tapers to thin distal part (Fig. 1L) in contrast to the more setose (7) N. haplochelus sp. n. with conventional taper to broader distal part (Fig. 1K).
The two frontal setae in the female N. ctenochelus sp. n. are diagnostically stout (Fig. 1D), in contrast to the conventional narrower frontal setae of N. haplochelus sp. n. (Fig. 1B). The spermathecal ducts are of even width in N. ctenochelus sp. n., but have a dilate section in N. haplochelus sp. n., and seminal vesicles are small with a neck in N. ctenochelus sp. n. but in N. haplochelus sp. n. are larger and lack a neck.
The described pupae of Nilotanypus especially from Roback (1986) and Roback & Coffman (1987, 1989) show subtle differentiation with variation in the thoracic horn and in the strength of abdominal armament. Separation of the Australian species depends upon the (unique) row of tubercles on the distal wing sheath of N. ctenochelus sp.n. (Figs 2C, 3A). The two Australian species may be separable also on the thoracic horn: in N. ctenochelus sp.n. the atrium is very narrow in the basal 1/3 and expanded from near the midpoint (Fig. 2B) whereas in N. haplochelus sp. the atrium broadens nearer the base (Fig. 2A).
The larvae of the two species of Australian Nilotanypus are differentiated by the posterior parapod in N. ctenochelus sp. n. having a long comb-toothed claw (Fig. 2P, 3B) that is lacking in N. haplochelus sp.n. – hence the species epithets. Other differences include dense-packed short comb-teeth claws (Fig. 2N) on the anterior parapod of N. ctenochelus compared to few simple spinules in claws of N. haplochelus; and the mid-tooth of the ligula tending to be wider and to protrude further in N. haplochelus (Fig. 2K). The location of the dorsal cephalic seta S 5 relative to the dorsal pore and lateral cephalic setae S 7 and S 8 may inform (Fig. 2F, G). Although the head capsule of N. haplochelus is narrower (cephalic ratio ~0.5) compared to N. ctenochelus (~0.6–0.7), the ratio varies with slide preparation. Otherwise, all mensural features ranges encompass both larval types.
Description
Male (n=1–3, all teneral). Total length ~ 1.3 mm, wing length 750–800 μm. Overall brown throughout, legs slightly paler, abdomen with slightly paler intersegments.
Antenna. With 14 flagellomeres, total length 487, terminal flagellomere 40, separate but not offset from penultimate (13th) flagellomere 122, 3× length of terminal flagellomere, apical 2 flagellomeres subequal to 6.5 (6–7) preceding segments. AR 0.50; terminal seta 45–50 long. Pedicel with 1–2 setae, scape without setae.
Head (Fig. 1C). Eye hairy with dorsomedial extension of 6 ommatidia long. Frontal setae 2, thin, at right angle to 10 uniserial temporal setae, all arising from paler field. Clypeal setae 15. Palp (2–5) 25, 47, 70, 100.
Thorax with uniserial tuberculose anterior margin, curved with posteromedian projecting small sense organ (half size of adjacent setal sockets); with 2–3 lateral antepronotal setae; ~17 unevenly uni-/biserial acrostichals; ~16–20 dorsocentrals, humeral cluster disorganised becoming uniserial in pale areas; isolated prescutellar, 10–12 prealars comprising anterior cluster of 4, posterior prealars disorganised; 1 supra-anal; scutellars with posteriormost row of 8 uniserial strong setae, with shorter to much smaller setae anteriorly numbering up to 22.
Wings hyaline, veins pale, membrane and veins densely setose, submarginal apical setae dense, strong, 100–120 long. Venation as in N. haplochelus. Squama with 16–20 uniserial setae,
Legs. Mensural: P 1 250–255, 212–225, 178, 75, 63, 52, 50; LR 1 0.83, BV 1 2.68, SV 1 2.62; P 2 320–350, 210–275, 245, 110, 90, 60, 55 LR 2 1.18, BV 2 2.53, SV 2 2.27; P 3 290–295, 200, –, –, –, –, –; spurs 1, 1, 1, each narrow, slightly bent, 30–40 long with basal fine spines (‘hairs’), without lateral comb teeth; tibial comb on P 3 comprising slightly curved spines ~30 long. Pseudospurs 30–35 long, 2.5 wide, 2 on subapex of ta 2 of midleg (P 2), 3 slightly longer on subapex of ta 3; seemingly absent on other legs. Claws simple, gently curved, distally rounded, with strong basal rounded lobe. Pulvilli absent.
Abdomen setose with setae as long as an abdominal segment, organised into partial anterior median and lateral bands, both tergal and sternal.
Hypopygium. Tergite IX posteriorly with 6 or 8 aligned long setae; proctiger gently curved (median hyaline). Gonocoxite cylindrical, 55–60 long, maximum width 40, microtrichose, with dense dorso-laterally originating setae>300 long, filling pharate pupal genital sheaths, antero-median inner surface with 4–5 medially-directed setae arising from strong tubercle bases, not coalesced to appear as a lobe. Gonostylus (Fig. 1I) 38–42 long, microtrichose, broadest near base, curved from midpoint distally tapering to narrow apex, with 2 fine outer setae, 1 internally, none adjacent to slender megaseta (1 wide, 6–7 long), continuing direction of apical gonostylus, Gc:Gs ratio 1.3–1.88. Phallapodeme strong, sternapodeme shallow arched.
Female (n=3, pharate/teneral). Total length ~ 2 mm, wing length ~550–650 μm. Overall brown.
Antenna with 12 flagellomeres, total length 287, ultimate ~76–78, with blunt apex; AR 0.32–0.37; terminal seta 100 long. Pedicel with 4–5 setae, scape with 4-5.
Head (Fig. 1D). Eye hairy with dorsomedial parallel-sided extension of 6–7 ommatidia. With 2 stout lanceolate frontal setae 40 long, aligned anteroposterior, separated from 8 slender uniserial temporals, all arising from paler field. Clypeal setae 20-23, ~100 long. Palp (1–5) 30, 25; 38; 50; 75.
Thorax. With tuberculose anterior margin, without posteromedian scutal sense pit. Setal pits (and setae) in each location (ac, dc, pa, scts) bimodal, all originating from pale areas of cuticle: 2–3 lateral antepronotal setae; ~22 acrostichals +/-biserial throughout, with isolated posterior dorsocentral prescutellar, 14–15 unevenly biserial dorsocentrals; 9–10 prealars separated into anterior 2–3 and posterior cluster; 1 supra-anal; scutellum posteriorly with 8 uniserial strong setae, more anteriorly with shorter / finer setae numbering up to 30.
Wings. Apparently as in male. Apical marginal setae up to 80 long. Squama with 17–19 uniserial setae.
Legs. Mensural: P 1 225–250, 220–230, 150, 75, 70, 55, 75, LR 0.67, SV 2.96–3.20, BV 2.18; spur 30; P 2 325–375, 225–238, –, –, –, –; spur 38–40; P 3 325–350, 300, –, –, –, –; spur 40. Tibial spurs 1, 1, 1, fine, straight, 30–40 long with basal fine spines (‘hairs’), without lateral teeth; tibial comb on P 3 comprising 4-5 straight spines, longest 25. Paired proximate pseudospurs 38–42 long, 2.5 wide, subapical of ta 1 of foreleg (P 1), no others detected. Claws simple, gently curved, distally rounded, with strong basal rounded lobe. Pulvilli absent.
Abdomen. Moderately dense setae more or less aligned in anterior and median transverse rows.
Genitalia: Gonocoxapodeme VIII weak. Gonapophysis VIII simple microtrichose lobe with short setae throughout. Gonotergite IX weakly protruding, without setae. Coxosternapodeme strong, dark, curved. Notum thin, short (40–50 long) 2× seminal capsule length, posterior part of rami 45– 50 long. Three globular seminal capsules, 25–28 diameter, with distinct neck; spermathecal ducts 120–125 long, of overall even width, bare, ending uncertain. Gonocoxapodeme VIII forming continuous arc across anterior vaginal chamber. Cerci squat, small, 20–25 × 15–18.
Pupa (n=10). Small, total length 2.0– 2.7 mm.
Cephalothorax. Thoracic horn (Fig. 2B) flattenedtubular, spinulose, 130–175 long, 3–3.5 × maximum breadth, with narrow poorly-defined atrium expanded only distally (beyond 50%), with ovoid corona 75–90 long (ratio 48–51%). Thoracic comb uniserial row of 12–15 apically rounded, tubercles, 12–16 (longest) diminishing in size laterad. Basal lobe 32–50 wide, 25–30 high. resembling sharkfin. Thorax microtuberculose anteriorly and close to mid-dorsal ecdysial line. Wing sheath apicodistally with row of c. 20 small marginal tubercles aligned on anterior distal sheath (Fig. 2C, 3A), nose shallow to strong.
Abdomen. Armament as in N. haplochelus, except reduced on anterior segments to very fine scattered spinules, more microtuberculose on caudal tergites and all pleurae. Setation apparently as in N. haplochelus including L setae fine, short on VII; on VIII the 5 taeniate LS are distributed across caudal 70% of segment. SVIII posteriorly with subapical spinules, 3–4 long, numbering>50 spinules, uni-biserial, continuous in male; multiserial, shorter and medially interrupted in female. Anal lobe in both sexes, 175–205 long, 170–190 wide, bare, without spinules on either margin, terminating with inwardly curved hyaline blunt hook; anal setae adhesive, with greatest width of anterior (AL 1) seta much narrower than broad posterior (AL 2) seta (width 5–8 versus 20–25). Genital sacs sexually dimorphic, of male tapering,> 400 long,>2× anal lobe; in female bluntly rounded, 0.4× anal lobe length. Bases of genital sacs microspinulose more so in male.
Larva (n=3–4). Head length 380–440, width 190– 240, cephalic index ~0.51–0.60. Yellow with mandible, ligula and occipital margin mid-brown.
Antenna: basal segment 140–155 long, segment 2 30–36, segment 3 ~ 5–6, segment 4 ~4 long; style and Lauterborn organ ~5 long; blade and accessory blade subequal to flagellum; AR 2.95–3.4; Ring organ slightly protruding at ~55–70% from base. Antenna / mandible ratio 4.2–4.8.
Mandible. 40–47 long, seta subdentalis on welldeveloped distal molar projection (‘tooth’), proximal to distinct, rounded inner tooth.
Maxillary palp. 21–23 long, ring organ faint ~60% from base, longest component of apical crown 16- 20 long.
Ligula. 35–39 long, 3–3.5 × as long as apical width, ‘waisted’, with 5 teeth, near straight with central tooth extending only slightly beyond outer teeth. Paraligula squat, bifid, 16 long, Pecten hypopharyngis with 6–8 teeth, innermost largest and directed antero-medially, remainder subequal / narrower points directed anteriorly.
Submentum / anterior gula. Ventrally V 9, V 10, VP, SSm as in N. haplochelus (Fig. 2F, left). Dorsally with S 7 well separated from S 8 with dorsal pit (DP) near midway, but closer to ecdysial line, S5 anterior to DP (Fig. 2G).
Abdomen. Anterior parapod with many small pectinate spinules (Fig. 2N) proximal to conventional claws. Posterior parapod 175–300 long, ventrally with slender spine, 130–185 long, inserted at 1/3 from base; solitary pectinate claw, 50–55 long with 16–21 internal teeth (Fig. 2P, 3B), amongst otherwise simple claws. Procercus slightly darkened posteriorly, paler anteriorly, length 42–50, width 12–16, bearing 7 anal setae length 300–400. Supra-anal seta strong, 200–250 long. Anal tubules narrow, tapering, hyaline, up to 400 long, often damaged.
description: Published as part of Cranston, Peter S., Krosch, Matt N. & Tang, Hongqu, 2022, Verifying Australian Nilotanypus Kieffer (Chironomidae) In A Global Perspective: Molecular Phylogenetic And Temporal Analyses, New Species And Emended Generic Diagnoses, pp. 12-31 in CHIRONOMUS Journal of Chironomidae Research 35 on pages 22-25, DOI: 10.5324/cjcr.v0i35.4832, http://zenodo.org/record/7996326