Riethia kakadu Cranston

Cranston, Peter S., 2019, Riethia (Kieffer 1917) (Diptera: Chironomidae) revised for the Austro-Pacific region, Zootaxa 4646 (3), pp. 461-500: 478-479

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Riethia kakadu Cranston


Riethia kakadu Cranston   sp.n.

( Figs 2E View FIGURE 2 , 3C, H, M View FIGURE 3 )


Riethia   K1 Cranston 1996; 2000.

Type material. Holotype ♂, AUSTRALIA, Northern Territory, Kakadu N.P., Radon Spring, 12°45’S 132°55’E, 13–14.iv.1989 (Cranston) #2206 ( ANIC) GoogleMaps   . Paratypes): 3♂, as holotype; ♂, Kakadu N.P., Coronation Hill, S. Alliga- tor R., 13°35’S 132°26’E, 4–5.vi.1988; ♂, Western Australia, Kimberleys, Adcock Gorge, 35 km SW Mt. Barnett, Gibb River Rd. [16°55'S 125°46'E] E[ucalyptus] camuldulensis, ' Lux' , 13– 14.8.1995, leg. M. Baehr ( ZSM) GoogleMaps   .

Other material (collected Cranston, deposited ANIC, unless otherwise stated, Pe excluded due to association by co-location only): 4 Pe, as holotype, 3 Pe as holotype except 6.vi.1988   ; Pe, Litchfield National Park , Petherick’s Rainforest, 13°07’S 130°39’E, 6.viii.1990 GoogleMaps   ; Pe, Coronation Hill, S. Alligator R., Gimbat spillway, 13°34’S 132°35’E, 19–20.iv.1989; 2 Pe, 13°10’S 130°41’E, Litchfield Park , Wongi Falls, 6.viii.1990 GoogleMaps   ; Pe, Koolpin Gorge, 13°30’S 132°35’E, 15/ 16.v.1992, #2213; Pe, Katherine Gorge, below gorge #1, 14°20’S 132°25’E, 21–22.v.1992; Pe, same except gorge #1, 14°18’S 132°26’E, 21.v.1992.

Identified on morphology as R. cinctipes   , but possibly R. kakadu   : Northern Territory, 4L, Kakadu N.P., Burdulba Ck., 5.i.2007 (Hanley et al.) ( MV NT11 B1 R1-4, all 3i)   .

Description. Male. Thorax yellow, with vittae weakly indicated as darker yellow; legs pale, without banding or with slight darkening of subapical femora. Wing membrane unmarked, veins pale. Setae of TIX fine, long, covering tergite. Gonostylus not broadened at junction with gonocoxite, which bears only simple setae. Superior volsella ( Fig. 2E View FIGURE 2 ) covered in microtrichia with 1 long seta near base of digitus, posterior projection well developed, setose, melding into inferior volsella; digitus medially-directed, narrow, apically rounded, devoid of microtrichia, with 2 long simple setae, 1 towards base, 1 nearer apex; inferior volsella strong, with 5–7 pectinate scales and several simple setae. Pseudovolsella a strongly protruding tubercle with 3–4 proximated long setae ( Fig. 2E View FIGURE 2 ). Mensural features as in Table 1 View TABLE 1 .

Female unknown.

Pupa (putative). Mid-brown, with darker brown dorsal thorax, anterior wing sheaths and lateral apophyses on abdominal segments V–VIII; comb brown. Cephalothorax rugulose with multiple rows of small tubercles along line of eclosion ( Fig. 3C View FIGURE 3 ). Abdomen ( Fig. 3H View FIGURE 3 ) with uninterrupted hook row occupying 40% of tergite width, conjunctival spinule bands on III and IV medially interrupted; pedes spurii B well developed; vortex strong. Tergite II with armament restricted to small triangular area anterior to hook row, without any indication of anterior transverse band, TII–VI with hour-glass shaped armament, TVII with strong anterior creases terminating without spinule; TVIII with microspinules anteriorly. Taeniate setae 3, 4, 4, 5, on VIII L 3–5 clustered. Comb ( Fig. 3M View FIGURE 3 ) with 1 stronger spine, 2–3 weaker posteriorly-directed spines. Anal lobe with 45–50 +/- biserial taeniae.

Larva unknown.

Etymology. From the main location, Kakadu, the federally managed national park. To be treated as a noun in apposition.

Diagnosis. The adult male has only simple setae on the gonostylus and the superior volsella, lacks pectinate scales. The digitus of the superior volsella lacks pectinate setae and seems characteristically narrow from the base, bearing only 1 inner and 1 outer seta. The pupa, which is associated only by co-occurrence, has an undivided hook row, lacks a conjunctival band on TV, and has the conjunctival rows on III and IV clearly divided medially.

Remarks. No molecular data are available: specimens collected for the project did not produce DNA.

DIstribution and Ecology. R. kakadu   is known from northern Australia, in the areas of seasonal monsoonal rainfall. Most specimens have been collected in Kakadu and Litchfield National Parks which preserve some of the best quality waterways in northern Australia.


Australian National Insect Collection


Bavarian State Collection of Zoology


University of Montana Museum














Riethia kakadu Cranston

Cranston, Peter S. 2019


Cranston 1996