Riethia noongar Cranston, 2019

Cranston, Peter S., 2019, Riethia (Kieffer 1917) (Diptera: Chironomidae) revised for the Austro-Pacific region, Zootaxa 4646 (3), pp. 461-500 : 480-481

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/7C2906DD-7E0D-49FD-893F-CA5231035B9D
taxon LSID	lsid:zoobank.org:act:7C2906DD-7E0D-49FD-893F-CA5231035B9D
treatment provided by	Plazi
scientific name	Riethia noongar Cranston
status	sp. nov.

Treatment

Riethia noongar Cranston View in CoL sp.n.

( Figs. 2G View FIGURE 2 , 4A, 4E View FIGURE 4 , 6B, J View FIGURE 6 )

urn:lsid:zoobank.org:act:

Riethia View in CoL ‘ V5 ’, Cranston 1996; 2000.

Type material. Holotype Le/Pe/ ♂, AUSTRALIA: Western Australia, Mitchell R., 34°50'S 117°25'E, 3.xii.1994 (Cranston) ( ANIC) GoogleMaps . Paratypes (collected Cranston , deposited ANIC, unless otherwise stated): Western Australia: 2 Pe, Denmark R., 34°52'S 117°16'E, 3.xii.1994 GoogleMaps , # 2205; 2 Pe , Shannon N.P., Fish Ck., 24.xi.1994 ; ♂, Deep River , drift, 34°48'S 116°37'E 21.iii.1989 (Nolte) ( ZSM) GoogleMaps [misassociated on slide, with pupa of R. donedwardi, Zuordnung der Exuvie unsichser]; Pe, lower Shannon R., 34°39'S 116°22'E, 23–24.xi.1994 GoogleMaps ; Pe, lower Shannon R., 34°51'S 116°22'E, 5.xii.1994 GoogleMaps ; Le / Pe / ♂, Le / Pe / ♀, Wungong Catchment , Seldom Seen Brook , 32°15'S 116°04'E, 26.viii.1982 (Edward / Bunn) GoogleMaps ( WAM).

Other material. Western Australia, L, Chesapeake Rd., lower Shannon R., 34°51'S 116°22'E, 5.xii.1994, #2204; L, Big Brook, 32°52.53"S 116°06.20"E, 7.x.2009 (Pinder) MV MRY09R3); 2L, ‘loc 543’, 3.v.1983, unknown collector GoogleMaps .

Excluded: material of molecular-diagnosed sister to R. noongar . New South Wales, L(? 3i), Glenbog SF., Brown Mt., Fastigata Rd. , Rutherford Ck., 36°36’S 149°47’E, 909 m a.s.l, 4.ii.2009 ( MV NSWRGCR9 ); L(3i, damaged), same except 27.xi.2010 ( MV NSWBMR1 ); ♂ (damaged in extraction) GoogleMaps Koskiuszko N.P., Charlotte’s Pass, Spencer’s Ck., 36°26’04”S 148°20’17” 1.xii.2010 ( MV NSWKOS25 AR1 ) .

Description. Male. Thorax yellow-brown, without distinct vittae; legs pale without banding, abdomen may be dark brown. Wing membrane unmarked. TIX setae thin, long, in dense cluster across tergite. Gonostylus broadened at base, bearing simple and weakly plumose setae. Superior volsella ( Fig. 2G View FIGURE 2 ) microtrichiose, with 4–5 scattered setae, posterior setose projection scarcely detectable, medially-directed part sub-triangular with very short digitiform extension, with 5–7 simple seta; inferior volsella large, posteriorly fused with superior, without pectinate scales, with many long simple setae. Inner gonocoxal setae strong, each of 3 distalmost arising from tubercle ( Fig. 2G View FIGURE 2 ). Mensural features as in Table 1 View TABLE 1 .

Female. Pigmented as male, AR 0.3, LR 1 1.06.

Pupa. Pale with yellow dorsal thorax, anterior wing sheaths and lateral apophyses on abdominal segments V– VIII; comb yellow. Cephalothorax weakly rugulose, with well-developed frontal warts (c. 50–60 µm long), bulbous to almost pyramidal-shaped ( Fig. 3B View FIGURE 3 ), dorsum tuberculose. Abdomen ( Fig. 4A View FIGURE 4 ) with uninterrupted hook row on II, 40–45% width of tergite; conjunctival spinule bands on III and IV. Pedes spurii B absent, vortex strong. Tergite II with anterior transverse patch of spines, almost disconnected from triangular mid-posterior patch, posterior width as hookrow, TIII–V with strong anterior spinules and rectangular medioposterior area, TVI spinule patch hour-glass shaped, TVII and VIII essentially bare. Anterior transverse band spines distinctly stronger and denser on II–V than more posterior tergites. Comb ( Fig. 4E View FIGURE 4 ) with 1 stronger, triangular spine projecting postero-laterally, 2–3 weaker, also postero-laterally directed spines. Anal lobe with 22–30 unevenly biserial taeniae.

Larva. Head capsule yellow with strong brown occipital margin, postmentum and mandible golden yellow, mentum and inner mandibular teeth brown (innermost 4 th incompletely separated from mola). Clypeus ( Figs 6B, J View FIGURE 6 ) variably trapezoid with clypeal setae in anterior 1/3. Inner margin of mandible with broad lobe beside insertion of seta subdentalis and 2 strong spines near mid-point of mola. Antenna with short pedestal (25–30 µm), AR less than 1.5, and each antennal segment shorter than that preceding. The ventromental plate is very short, only 80% of the mentum width. Mensural features as in Table 2 View TABLE 2 .

Etymology. Named for the noongar, aboriginal inhabitants of south-western Western Australia for the past tens of thousands of years. The traditional lands of the noongar community are substantially congruent with the range of this taxon. To be treated as a noun in apposition.

Diagnosis. The adult male of R. noongar has unbanded legs, gonostylus with only simple setae, and superior volsella and inferior volsella with only simple setae (i.e. lacking pectinate setae on the hypopygium).

The pupa of R. noongar has a continuous hookrow, and continuous conjunctival spine bands on only III and IV, with V bare. Tergite II is broadly spinulose, with a postero-median spinule area extending anteriorly to a broad transverse spinule area. The tergites are pale with apophyses indistinctly delimited. The cephalic area has smooth warts that taper, and TVII and all sternites are essentially bare.

The larval mentum and inner mandibular teeth are distinctly dark (brown) relative to the golden head colour. The antenna has the 3 rd antennal segment shorter than the 2 nd and the AR is less than 1.5.

Remarks. Molecular data demonstrate that the only successfuly sequenced R. noongar differs by 12% from a small cluster of specimens from eastern Australia (see above). These combined form a sister to a substantial group including R. queenslandensis and R. azeylandica , phylogenetically distant from the New Zealand R. zeylandica . This sister group to R. noongar , known informally previously as ‘eastern V5 ’, occurs as larva at the well-sampled Rutherford Creek. The larval MV NSWRGCR9 seems to be a 3 rd instar and a tentatively conspecific (non-MV) 4 th instar indicate that the clypeus is a very similar shape to that of R. noongar ( Fig. 6I View FIGURE 6 ), but the antennal pedestal is well developed and ventromental plate subequal to the width of the mentum (rather than c 80% ( Table 2 View TABLE 2 ‘noongar’ v ‘sister to noongar’). The 3 rd specimen in the clade is an adult male (also badly damaged) from high elevation in Kosciuszko N.P. The poor quality and shortage of critical specimens in ‘ sister to noongar’ precludes description although very likely a new species.

Distribution and ecology. Riethia noongar is endemic to south-western Western Australia, from 32°S to 35°S. This area, known colloquially as the 'jarrah belt', supports 'relictual' aquatic organisms ( Bunn et al. 1986; Edward 1989).