Riethia cinctipes Freeman

Cranston, Peter S., 2019, Riethia (Kieffer 1917) (Diptera: Chironomidae) revised for the Austro-Pacific region, Zootaxa 4646 (3), pp. 461-500 : 467-469

publication ID	https://doi.org/ 10.11646/zootaxa.4646.3.3
publication LSID	lsid:zoobank.org:pub:25CA4A18-955F-4EA7-8978-E93032B54A2E
persistent identifier	https://treatment.plazi.org/id/B3370110-9B39-1E68-C68C-FC3BFF133576
treatment provided by	Plazi
scientific name	Riethia cinctipes Freeman
status

Treatment

Riethia cinctipes Freeman View in CoL

( Figs. 2B View FIGURE 2 , 3E, 3J View FIGURE 3 , 4I View FIGURE 4 , 5A, E View FIGURE 5 , 6E View FIGURE 6 )

Riethia cinctipes Freeman 1961 View in CoL ; Cranston 1966, 2000.

Riethia Pe View in CoL ‘Brisbane’ Cranston 1966, 2000

Type material. Paratypes, ♂, pinned, separate hypopygium on celluloid mount, ‘ F.C.T. Blundells’ [ AUSTRALIA, Australian Capital Territory, Blundell’s Farm ] 18.2.1931, A.L.Tonnoir [ANIC]. Riethia cinctipes Freeman det. Freeman 1960 (2 labels) ; ♀, pinned, ‘ Stanwell Pk’ [New South Wales], 2 Mar 23 [1923] ; second label as ♂ above.

Other material (collected Cranston, deposited ANIC, unless otherwise stated) : Queensland, 2♂♂, 1 ♀, McIlwraith Range, 15 km WNW Bald Hill, 13°43’S 143°19’E, 27.vi.–12.vii.1989 (Naumann, ANIC expedition) GoogleMaps ; 1 ♂, 7 miles N. Hope Vale Mission, 4.x.1980 (at light) (Colless) #2542 ; 5 Pe , Emmagen Ck., 16°02.7”S 145°27.0”E, 9/ 10.ix.1997 (McKie) #2068 ; 2Pe, Mason Ck., 16°05.08”S 145°27.36”E, 23.iv.1999 ; 3 Pe , Oliver Ck.,16°08.3”S 145°26.7”E, 9/ 10.ix.1997 (McKie) #2073,4, 7 Pe , 23.–23.iv.1999 ; L, 6Pe, Mossman, Rex Ck., 16°28’S 145°19’E, 5–6.iv.1997, #2543, 5 GoogleMaps ; 6 Pe , same except 27–28.viii.1997, #2546 ; 6 Pe , same except 17–18.xii.1997, #2544 ; 2L, Le /P ♂, Pe, 19–20.x.1998 (Cranston & Dimitriadis) #2076-8 ; 10 Pe, Mt. Lewis , trib. Churchill Ck., 16°34’S 145°20’E, 6–7.iv.1997, #2547-8 GoogleMaps ; 3 Pe , Clohesy R., 7–8.ix.1997 (McKie) #2067 ; 5Pe, Mareeba, Davies Ck., above falls, 17°01’S 145°35’E, 11–12.iv.1997 #2549 GoogleMaps ; 2 Pe , same except 19–20.vi.1997 ; Pe , same except 27–28.viii.1997, # 2065-66 ; 2 Pe same except 17–18.xii.1997, #2066 ; 2 Pe , Kauri Ck., 11.vi.1997 (McKie) #2069 ; 2 Pe, Mt. Haig ,?U. Emerald Ck., 17°06’24”S 145°36’52”E, 17–18.xii.1997, #2550 GoogleMaps ; Pe, Tinaroo, unnamed Ck., 17°09’S 145°37’E, 11– 12.vi.1997 ( McKie ) #2075 GoogleMaps ; 4Pe, Bartle Frere, Junction Ck., 17°16’S 145°55’E, 1–4.iv.1997, #2553 GoogleMaps ; Pe , same except 27–28.viii.1997, #2551 ; 5 Pe , same except 17–18.xii.1997 ,, #2552 ; 2Pe, Herberton, Carrington Falls Ck., 17°20’S 145°27’E, 9–10.iv.1997, #2554 GoogleMaps ; Pe, Nigger Ck., 17°27’S 145°29’E, #2555 GoogleMaps ; P ♂, 8 Pe, Palmerston N.P., Learmouth Ck., 17°35’S 145°42’E, #2062, -2556 GoogleMaps ; Tchooratippa Ck. , 17°37’S 145°45’E, 8–9.iv.1997, #2557 GoogleMaps ; 2 Pe, Python Ck., 17°46.2’S 145°35.4’E, 2–3.xi.1997 ( McKie ) #2072 GoogleMaps ; Pixies Ck. , 2–3.ix.1997, 17°47’S 145°41’E ( McKie ), #2070-1 GoogleMaps ; Le / Pe / ♂, 2 Le / Pe / ♀, nr Cardwell, 5-mile Ck., 17.xii.1997, 18°19’S 146°02.55’E, #2064 GoogleMaps ; L, same except 17.xiii.1997 ; Le / Pe / ♀, Paluma, Birthday Ck., 18°58’S 146°09’E, 24.x.1998 (McKie) GoogleMaps ; 3 Pe , Paluma, unnamed Ck. S. Paluma, 25–26.iii.1998, #2558 ; Le / Pe / ♀, Paluma, Camp Ck., 18°68’S 146°09’E, 5.v.1999 (Dimitriadis) ; Le /P ♂, Yaccobine Ck., 17.v.1988 (Edward), #2061 ; 2Pe, N.W. Brisbane, Bundaroo Ck., 26°42’S 152°34’E, 27.ix.1989, #2559. GoogleMaps

New South Wales: 5 Pe , Chaelundi N.P., Chandlers Ck., 30°02.22’S 152°29.26’E, 11.iv.1996, #2560 GoogleMaps ; 9 Pe, nr Dorrigo , Eve Ck., 30°16’S 152°50’E, 9.x.1996, #2056 GoogleMaps ; 2 Pe, Barren Ground N.P., Redback Stream , 34°40’S 150°44’E, 9.iv.1994, #2055 GoogleMaps ; Pe , Endrick R., 6 km NE Nerriga, 35°05’S 150°08’E, 1.ix.1988, #2053; Pe / ♂, Rutherford Ck., 11.xi.1961 (Brundin) ( ZSM) GoogleMaps .

Australian Capital Territory ( ACT): Pe, Brindabellas, Lees Ck., 35°22’S 148°50’E, 12–13.i.1998 (Willis & Cranston) #2058 GoogleMaps ; same except 24.i.1998 (Willis) #2057.

Northern Territory: 4 ♂, Pe, Kakadu N.P., Radon Spring, 12°45’S 132°55’E, 13–14.iv.1989, #2051 GoogleMaps ; 2Pe, Litchfield N.P., Wongi Falls , 13°10’S 130°41’E, 6.viii.1990, #2054. GoogleMaps

Victoria: L., nr Anglesea, Angahook Forest , AV #82.1, 19.iii.1972 (Martin) .

Molecular ( MV) larvae. Queensland, 2L, Emerald Ck., 16°58.50’S 145°34.00’E, 8.ix. 2007, 360 m a.s.l. (Krosch) ( MV FNQDE 1R, DE1.24) GoogleMaps ; L, Atherton, Nigger Ck., 17°26’S 145°28’E, 1.ix.2005 (Krosch) ( MVN 7) GoogleMaps ; 2L, Paluma, Birthday Ck., 18°58.35’S 146°09.26’E, 24.ix. 2008, 700 m a.s.l. (Krosch) ( MV FNQBC 8R1-2) GoogleMaps ; L, Paluma, Little Birthday Ck./ Camp Ck., 18°58’22”S 146°09’52”E, 850 m a.s.l., 21.ix.2008 (Krosch) ( MV FNQC- C4R1) GoogleMaps ; L(3i) same except 22.ix.2008 ( MV FNQBC 7R1), L, same except 21.ix.2008 ( MV PAa2, 15) ; 2L, Cloudy Ck., 18°59.50’S 146°12.30’E, 25.ix. 2008, 720 m a.s.l. (Krosch) ( MV FNQCCR 1, 2,3) GoogleMaps ;. 3L, Cooloola N.P., Frankis Gulch, 26°02.50’S 153°04.44’E, 18.iv.2009 (Krosch) ( MV AU09FG3, 4, 10) GoogleMaps . Northern Territory, 4L, Kakadu N.P., Burdulba Ck., 5.i.2007 (Hanley et al.) ( MV NT 11B1R1-4, all 3i) [possibly unknown larva of R. kakadu ].

Description. Male. Thorax yellow, with distinct brown vittae (dark area may be restricted to anterior of median vitta and lateral edges of lateral vittae) and transverse pleural stripe. Legs with dark band on mid-femur, femoral apex, base, mid and apex of all tibia, apices of all tarsomeres (5th may be all dark). Wing membrane infuscate, with transverse dark patch including both ‘forks’. Abdomen with posterior third of tergite II with dark transverse band; all succeeding segments with dark postero-lateral areas, genitalia brown. Setae of TIX long, slender, arranged in two clusters, separated medially by non-setose strip. Gonostylus relatively short, not tapered at gonocoxite junction, bearing essentially simple setae, some with fine branches, all distally pointed. Superior volsella ( Fig. 2B View FIGURE 2 ) without microtrichia in basal or medial area, proximo-laterally with 4–6 long setae, without posterior projection, medially-directed lobe-shaped digitus without microtrichia, with 7–12 simple seta, ending in narrowed lobe or notched; inferior volsella small, mainly appressed to inner contour of gonocoxite and linked to superior volsella, without pectinate scales, with long simple setae and dense microtrichiae extending from distal area linking to superior volsella. Pseudovolsella no more than weak bulge with strong setae not differentiated from linearly aligned on inner gonocoxite ( Fig. 2B View FIGURE 2 ). Mensural features as in Table 1 View TABLE 1 .

Female (n=3, part teneral). Colour similar to male, yellow with median vitta anteriorly brown oval, lateral vittae pale brown with darker outline anteriorly and laterally, extending from mid-scutum to just anterior to pale scutellum; central postnotum brown. anepisternum with broad brown linear ‘smear’. Wing with infuscate band over cross-veins, paler apically and at base. Legs with transverse band at 2/3 on forefemora, dark brown at distal apices of femora and proximal base of tibia (‘knees’); tibial apices darkened near spurs; apices of tarsomeres brown; foreleg with darkest pigment, mid and hind legs less intense. B.l. 6.0 mm, W.l. 2.5 mm. Antenna flagellomeres 140–180, 105–115, 100–105, 95–100, 140–165; AR 0.32–0.34. 38–40 clyp, 16 multiserial orbitals. Palpomeres 50, 50–55, 170–300, 180–280, 260–360. Thorax. Ac?7–9, Dc 14, Pa 2–3, Scts 14–15. Wing V.R. 1.12. Vein setation: R 28–37, R 1 24–34, R 4+5 58–67; sq. 11–19. Leg lengths: P 1 1400, 1440, 1440, 800, 640, 480, 220; P 2 1560, 1380, 780, 440, 320, 200, 110; P 3 1400, 1380, 940, 600, 420, 240, 120. Ratios: LR 1 1.01, LR 2 0.56, LR 3 0.68;, BV 1 2.04, BV 2 3.4, BV 3 2.7; SV 1 1.97, SV 2 3.77, SV 3 2.96. Foretibial comb, 50 with 5–6 lateral teeth each side; midtibials 65, 75, rear 65, 70, with strongly developed lateral teeth.

Pupa. Brown with dark dorsal thorax, anterior wing sheaths and lateral apophyses on all abdominal segments; comb brown-black. Cephalothorax with strong frontal warts, thorax rugose with multiserial rows of dark tubercles on dorsum. Hook row on II continuous [one exception, see remarks], occupying c 50% of tergite width. Conjunctival spinule bands on III–V narrowly separated to almost completely contiguous with posterior tergal armament, on V narrower and maybe medially sparse. Pedes spurii B absent, vortex strong.Abdomen ( Fig. 3E View FIGURE 3 ): Tergite II with triangular area of spinules anterior to and narrower than hookrow, without any more anterior spinules, TIII–V largely infilled with spinules, TVI with anterior-median oval area, separated from posterior transverse band; TVII and VIII with anterior and posterior areas of fine spinules. Comb ( Fig. 3J View FIGURE 3 , 4I View FIGURE 4 ) variable, often with “windows” of pale cuticle within, with 1 strong, inner spine directed postero-medially and 3–4 subordinate spines.

Larva. Head capsule yellow including postmentum and genae, with dark occipital margin, mandible golden yellow, bases of inner 4 mandibular teeth and mental teeth golden-brown. Clypeus lozenge-shaped, elongate-ovoid, 3× as wide as long ( Fig. 5A View FIGURE 5 , 6E View FIGURE 6 ). Antenna ( Fig. 5E View FIGURE 5 ) with 3 rd segment longer than 2 nd, characteristically narrowed basally and with thin wall on one side; segment 4 <2/3rds length of segment 2 (14–18μ to 21–25μ). Ventromental plate variable, with specimens from Cloudy Ck 20% longer than mentum width, with all others close to 100%. Mensural features as in Table 2 View TABLE 2 .

Diagnosis. Adults of R. cinctipes have distinctively ‘banded’ legs and pigmented wings, but both vary in intensity perhaps associated with tenerality. Amongst the males of the 5 taxa with patterned-legs, geographic distribution and male genitalia provide discriminatory features. Riethia cinctipes is an eastern Australian species as is R. stictoptera , the others are from Western Australia or New Caledonia. The characteristic gonostylus of R. stictoptera differs from the conventional one of R. cinctipes . The digitiform appendage of the superior volsella, absent in R. stictoptera , differs in each of the other banded-leg species, see key and Figures 2B, 2C, 2G View FIGURE 2 . Specifically, the medially-directed digitus has a notch or apical tooth on the anterior margin in R. cinctipes whereas the digitus tapers evenly to a point in R. donedwardi .

The pupa of R. cinctipes also resembles that of R. stictoptera with undivided hookrow and only conjunctives III and IV with continuous rows of spinules and with sparse spinules on the posterior of TII. The pupa of R. cinctipes lacks pedes spurii B and tergite II has a moderate-sized spinule area, about as wide as the hook row, in contrast to a smaller spinulose area in R. stictoptera . Some southern exuviae and those from N.T. have the conjunctival bands more distinctly separated from the tergal spinulation. None of these are reared, and for the present they are treated as variants of R. cinctipes .

Larvae of R. cinctipes have a low AR (<1.2) as does R. donedwardi , but the mentum and inner mandibular teeth are brown compared to the yellow-gold teeth in R. donedwardi which is a species restricted to Western Australia. The 3 rd antennal segment is much longer than the 2 nd but is subequal in R. donedwardi and also is narrowed, seemingly thinner-walled, medially ( Fig. 5E View FIGURE 5 ). Further differentiation comes from the lozenge-shaped (elongate-ovoid) clypeus, 3× as wide as long.

Remarks. There is substantial variation in the setosity of the male thorax. For example, a reared male from 5- mile Creek has multiple rows of dorsocentrals, but unreared males from further north in Queensland have fewer near uniserially arranged. The ventromental plate with respect to the width of the mentum falls in to two classes: close to equal (ratio=1.0) or greater (ratio = 1.2 for same width of mentum). This partially conforms to variation seen in molecular barcode patterns—unfortunately only 1 specimen produced 4 genes.

DIstribution and ecology. R. cinctipes is an eastern Australian species with a range extending from 13°S - 14°S in Kakadu and Litchfield National Parks, Northern Territory and north Queensland, southwards to an isolated record from south coastal Victoria. Most reports are from the north to central parts of this range, with no specimens from Tasmania. Most sites are from running waters, but this habitat is over-represented due to use of drift nets in lotic conditions. Larvae do occur in billabongs and standing waters in rivers, usually with good to excellent water quality.