Riethia azeylandica Cranston, 2019

Cranston, Peter S., 2019, Riethia (Kieffer 1917) (Diptera: Chironomidae) revised for the Austro-Pacific region, Zootaxa 4646 (3), pp. 461-500 : 465-467

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Riethia azeylandica Cranston

sp. n.

Riethia azeylandica Cranston sp. n.

( Figs. 2A View FIGURE 2 , 3A, 3D, 3I View FIGURE 3 , 5D View FIGURE 5 , 6D View FIGURE 6 )


Riethia zeylandica (pro parte): Cranston 1996; 2000.

Type material. Holotype Le/Pe/ ♂, AUSTRALIA, Australian Capital Territory, Namadgi N.P., Brindabellas , Lees Ck., 35°22’S 148°50’E, 12–13.i.1998 ( Cranston ) ( ANIC) GoogleMaps . Paratypes (collected Cranston, deposited ANIC, unless otherwise stated) : Queensland: 3Pe [1 on same slide as paratype of R. queenslandensis ], Mt. Haig , Emerald Ck., 17°06'24"S 145°36'52"E, 17–18.xii.1997, #2219 GoogleMaps ; Pe, Palmerston N.P., Learmouth Ck., 650 m. a.s.l, 17°35'S 145°42'E, 8–9.iv.1997, #2220 GoogleMaps ; 1♂, Cardwell, 5-mile Ck., 18°20’S 146°03’E, 1–4.iv.1997 GoogleMaps ; 2Pe, N.W. Brisbane, Bundaroo Ck., 26°42'S 152°34'E, 27.ix.1989, #2218. GoogleMaps

New South Wales, 2 Pe, Chaelundi S.F., Chandlers Ck., 30°02.22'S 152°29.26'E, 11.iv.1996, #2221 GoogleMaps ; Pe, nr Dorrigo, Eve Ck., 30°16'S 152°50'E, 9.x.1996, #2222 GoogleMaps ; Pe, Warrumbungles, Timor Rock. Shawn's Ck., 31°16'S 149°09'E, 15.ix.1989, #2223 GoogleMaps ; ♂ pinned, abdomen on celluloid mount, ' Hornsby' , 2/12/1958 (D.J. Lee) det. Freeman; 6L, 2Pe, 34°24'S 149°09'E, Macquarie Pass, Macquarie Rivulet, 12.iii.1994, #2224 GoogleMaps ; Pe, Endrick R., 6 km e. Nerriga, 35°05′S 150°08′E, 1.ix.1988, #2227; Le / Pe / ♂, Kangaroo Valley, Bugong Rd ., 12.xi.1990 (Edward), #2226 GoogleMaps ; Pe, Micalong Ck., 35°17′S 148°31′E, 14.i.1992, #2228; Pe, Budawangs, Yadboro R., 28–29.xii.1993 #2229; Le /P ♀, Bimberamala Ck ., 28.ix.1996 (Cranston & Gullan), #2230 GoogleMaps ; 2 Le / Pe / ♂, 4 Pe, Currowan S.F., Cabbage Tree Ck. , 35°34’S 150°02’E, 30.iii.1994, #2229 GoogleMaps ; L, Pe, Monga, Mongarlowe R., 35°23’S 149°55’E, 2.ii.1991, #2234 GoogleMaps ; 2Pe, Brindabella, Goodradigbee R., 35°23’54”S 148°44’51”E, 4.i.2001 GoogleMaps ; 6Pe, Kosciuszko N.P., Murrumbidgee R., 35°38’S 148°34’E, 13–14.xi.1993, #2232; 3Pe, Yarrangobilly R., 14–15.i.1991, #2233 GoogleMaps ; 2Pe, above Captains Flat, Molonglo R., 35°35’S 149°28’E, 6.iii.1993, #2235; 8L, -. v.1988 (Atkins) GoogleMaps ; 2 Pe, Brown Mountain , Rutherford Ck., 36°36’S 149°47’E, 16.x.1990 (Cranston & Edward), #2239 GoogleMaps ; Pe / ♂, 3 Pe , same except 4.iii.2009 ( MV NSW RGCR1 ); 2 Pe, Mt Imlay, Wallagaraugh R., 37°15’S 149°41’E, 13.i.1994, #2240 GoogleMaps ; 3Pe, Imlay Ck., 13.i.1994; 37°16’S 149°40’E. GoogleMaps

Australian Capital Territory, Brindabellas, Bramina Ck., 35°16’S 148°45’E, 29.viii.1988, #2242 GoogleMaps ; ♂, Black Mt, malaise trap, 35°16’S 149°06’E, -. i.1988 ( Irwin ) #2251 GoogleMaps ; ♂, L. Burley Griffin, 35°18’S 149°07’E, 18.x.1988, #2243 GoogleMaps ; ♂, Cotter, Paddys R. 15.ix.1988; 35°18’S 149°07’E, 15.ix.1988; #2244; GoogleMaps Pe, Pierces Ck., 35°20’S 148°56’E, 24.x.1991 ( Drayson ) #2252 GoogleMaps ; 2 Pe, Vanity Crossing, Cotter R., 16.x.1991, 35°21’S 148°53’E, 16.x.1991 ( Drayson ) #2252 GoogleMaps ; L, Warks Ck., 35°21’S 148°52’E, 26.iv.1988 ( Calder ) #2244; GoogleMaps 3Pe, Brindabellas, Lees Ck., 35°22’S 148°50’E, 12–13.i.1998 GoogleMaps ; 3L, Le/P ♂, Le, Pe/ ♀, Condor Ck., 35°22’S 148°51’E, 6.iii.1988, #2246-8, 2Pe, 24.iii.1991, #2249; ♂, 7–13.iii.1998, #2254 GoogleMaps ; Le/Pe/ ♀, Blundells Ck., 35°22’S 148°50’E,. ix.1999; GoogleMaps L, Namadgi N.P., Orroral R., 35°39’S 148°59’E, 21.ii.1988, #2250 GoogleMaps ; Pe, Namadgi N.P., Gudgenby R., 35°41’S 149°00’E, 14.ii.1988 GoogleMaps ; ♂, Brinda- bellas, Bushranger Ck., ex-wood, 35°25’S 148°50’E, 23.i.1996 ( McKie ) #2255 GoogleMaps . ♂ (slide from pinned, by Cranston), ‘Lee Spring’, 13.xi.1938 (A.L. Tonnoir), det. Freeman.

Victoria, 2Le/Pe/ ♂, Le/Pe, 2Pe, 2♂, Buckland R., 36°48’S 146°51’E, 4.vii.1991 (Cook) #2261-3 GoogleMaps ; Le/Pe/ ♂, Le/Pe, 6.xi.1990 (Cook) #2256-7 ; Le/Pe/ ♂, 3Pe, 1♂, 6.v.1991 (Cook, Cranston, Nielsen) #2260 ; Pe, 2P ♂, P ♀, Tambo R., ‘TPC’, 36°57’S 147°56’E, 27.iii.1991 (Hortle) #2276 GoogleMaps ; 2 Pe, P ♂, ‘CC10’, 23.iii.1990 (Hortle) #2264 ; P ♂, ‘TBTS’ 36°59’S 147°51’E, 28.iii.1991 (Hortle) #2267 GoogleMaps ; P ♂, d/s S. branch, 37°01’S 147°53’E, 8.iii.1990 (Hortle) #2265 GoogleMaps ; 22.iii.1990; P ♀, ‘up Wilga Weir’, 37°00’S 147°52’E, 30.iii.1993 (Hortle) #2275 GoogleMaps ; 15L, 2L/P, 3 Pe, P ♀, 2P ♂, Bindi, 37°08’S 147°49’E, 23.iii.1991 (Hortle) # 2269-74 GoogleMaps ; L, 1♂, Cumberland Falls , 38°34’S 143°56’E,. xii.1971 (Fuehrer). GoogleMaps

Tasmania: 1♂, L. Price, 41°50’S 146°08’E, 24.i.1990, #2279. GoogleMaps

Other material. Queensland, 2L, Lamington N.P., Coomera R., 26°11’S 153°10’E, 25.viii.2007 ( Krosch ) ( MV SEQ15 , 23 ) GoogleMaps . New South Wales: 3L (on 1 slide) Currowan S.F., Cabbage Tree Ck., 35°34’S 150°02’E, 2.i.2009 ( MV AU09 CTCR11-13 ) GoogleMaps ; 12L, Glenbog SF., Brown Mt, Fastigata Rd, Rutherford Ck., 36°36’S 149°47’E, 909 m a.s.l, 4.ii.2009 ( MV NSWRGCR2-7 , 10-15 ) GoogleMaps , 2L same except 27.xi.2010 ( MV NSWBMR3 , 4 ) ; ACT: L, Blundell’s Ck.,.2010 ( Krosch ) ( MV BLCR2 ) . Victoria, L, 8 km s Mitta Mitta, Snowy Ck., 36°34’13”S 147°24’58”’E, 19.ii.2005 ( MV V903 ) (misidentified previously as R. stictoptera (in Cranston et al. 2012) ; L, Buckland R. , 36°47’46”S 146°50.57”’E, 18.ii.2005 ( MV V507 ) ; L, Fyans Ck., Grampians Bridge Rd, 37°15’S 142°32’E, 11.xi.2009 ( Brooks ) ( MV AU09 RCR1 ) GoogleMaps ; 4L, Grampians N.P., Zumsteins, Mackenzie R., 37°05’S 142°51’E, 7–8.i.2001 ( MV VIC- 11GZR4, 1, 2, 3) GoogleMaps , 3L, downstream Zumsteins, 37°05’34”S 142°20’29’’E, 11.xi.2009 ( Brooks ) ( MV AU09 MKRR2 , 1,3 ). GoogleMaps

Description. Male. Thorax brown, with darker vittae; legs brown, without banding. Wing membrane clouded around veins and in anal area; veins yellow-brown. Setae of TIX fine, evenly distributed. Gonostylus merged with gonocoxite, which bears only simple setae. Superior volsella ( Fig. 2A View FIGURE 2 ) predominantly bare, excepting 4–5 long setae disto-laterally, posterior setose projection weak and contiguous with inferior volsella, medially-directed apically rounded digitus devoid of microtrichia, with 7–9 simple setae; inferior volsella well developed, basally appressed to inner contour of gonocoxite and linked to superior volsella, with 6–7 pectinate scales and many long simple setae. Pseudovolsella 3 weakly clustered long setae without tubercle development ( Fig. 2A View FIGURE 2 ). Mensural features as in Table 1 View TABLE 1 .

Female, Pigmentation as in male, AR 0.4. LR not measurable.

Pupa. Pale yellow with darker yellow dorsal thorax, anterior wing sheaths and lateral apophyses on abdominal segments V–VIII; comb yellow-brown. Frons with very weak warts ( Fig. 3A View FIGURE 3 ), cephalothorax rugulose with several rows of dorsal tubercles. Abdomen ( Fig. 3D View FIGURE 3 ) with continuous hook row on II occupying c 50% of tergite width, and complete conjunctival spinule band on III and IV. Pedes spurii B very weak to absent; vortex strong. Tergite II with quite dense armament in hour-glass shape, with anterior transverse band distinctive but not as broad as posterior armament, TIII-V rather similar to TII, perhaps denser, TVI with oval anteromedian patch separated from well-developed posterior band; TVII and VIII almost bare. Taeniate setae V–VIII 3, 4, 4, 5; on VIII evenly distributed along segment. Sternites bare. Comb ( Fig. 3I View FIGURE 3 ) with 1 stronger posteriorly-directed outer spine and 2–3 weaker subsidiary spines, also directed posteriorly. Anal lobe with 60–65 biserial taeniae.

Larva. Head capsule yellow with posterior half of head variably darkened, sometimes equally darkened as brown occipital margin, mandible golden yellow, mentum and inner 4 mandibular teeth brown (innermost 4 th completely separated from mola). Clypeus ( Fig.6D View FIGURE 6 ) trapezoid, with clypeal setae close together, in anterior 1/3 of sclerite. Inner margin of mandible with broad spine beside insertion of seta subdentalis and 3 serrations further towards base of mola. Antenna ( Fig. 5D View FIGURE 5 ) with AR 1.9–2.1, arising from distinct pedestal, each segment shorter than that preceding (thus 3 rd shorter than 2 nd), and 4 th distinctly shorter than 3 rd. Mentum and ventromental plate subequal in width. Mensural features as in Table 2 View TABLE 2 .

Diagnosis. The adult male of R. azeylandica is distinguished from R. queenslandensis (q.v.) only with difficulty, with differences of uncertain significance in shape and setation of the digitus of the superior volsella, notably the presence and number of pectinate setae on the volsellae and a weaker pseudovolsella. Distinction is clearer on the immature stages.

Pupal exuviae of R. azeylandica lack cephalic warts (present in R. queenslandensis ) and the hook row on II is complete as are the conjunctival bands, which are restricted to III and IV. Differentiation from R. queenslandensis relies not solely on the cephalic warts, but notably differing also in the density of spinulation on the posterior tergites ( Fig. 4M View FIGURE 4 ) and in the spinulose posterior sternites ( Fig. 4N View FIGURE 4 ). The western Australian R. noongar differs in the cephalic warts being separated at their bases, the bare sternites (and TVIII) and perhaps in the clustering of the lateral taeniate seta of segment VIII. In R. azeylandica these setae are more evenly spaced, unlike the clustered L 3–5 in R. noongar . Separation from the pupa from R. phengari is based on the lack of cephalic warts, the very pale exuviae with faint apophyses, and the number of teeth in the comb ( Fig. 4J View FIGURE 4 ).

Larvae of R. azeylandica and R. queenslandensis have a distinctively darkened posterior head, and resemble one other also in having a well-developed antennal pedestal and high antennal ratio (close to 2) deriving principally from short 3 rd and 4 th segments. Seemingly the relative lengths of antennal segments 3 and 4 distinguish—in R. queenslandensis these segments are subequal in length, in R. azeylandica , the 3 rd is clearly longer than 4 th. The shape of the clypeus ( Fig. 6D v. 6 M View FIGURE 6 ) may distinguish although the amount of variation is larger than illustrated.

Etymology. The species epithet is derived by adding the prefix—“a’ indicating it not the same species as R. zeylandica with which it was confused but which is restricted now to New Zealand.

Remarks. This species conforms to the concept of R. zeylandica in Australia when Freeman (1961) treated it as conspecific with the New Zealand species ( Freeman 1959). Morphology plus unpublished molecular data shows distinction of all Australian species from the New Zealand species. Molecular evidence for some internal structuring cannot be substantiated from morphology due to inability to separate this from the extensive geographic range of molecular samples—from 26°S to 37°S.

Re-examination of the morphology of larva voucher MV 903 in Cranston et al. (2010) allows re-identification as the new species R. azeylandica and not R. stictoptera as stated. This is supported by DNA data.

Distribution and ecology. R. azeylandica is sympatric with R. queenslandensis in Upper Emerald Creek on Mt. Haig on eastern (coastal) edge of the Atherton Tableland in tropical far North Queensland. This is the most northerly location for R. azeylandica , albeit at over 1000 m. elevation. Otherwise R. azeylandica is a more southern (temperate) species, with R. queenslandensis a species more typical of the tropical north. Riethia azeylandica is found in running waters from pristine to heavily polluted (e.g. Molonglo River, Captains Flat, NSW, see Cranston 2017). The only record from Tasmania is an adult male from Lake Price, at an elevation of about 1500 m a.s.l.


Australian National Insect Collection


University of Montana Museum














Riethia azeylandica Cranston

Cranston, Peter S. 2019

Riethia zeylandica

Cranston 1996