Riethia wazeylandica Cranston, 2019

Cranston, Peter S., 2019, Riethia (Kieffer 1917) (Diptera: Chironomidae) revised for the Austro-Pacific region, Zootaxa 4646 (3), pp. 461-500 : 488-489

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/DDA74A70-524C-4956-BA87-11AE029E4413
taxon LSID	lsid:zoobank.org:act:DDA74A70-524C-4956-BA87-11AE029E4413
treatment provided by	Plazi
scientific name	Riethia wazeylandica Cranston
status	sp. nov.

Treatment

Riethia wazeylandica Cranston View in CoL sp.n.

( Figs 2L View FIGURE 2 , 6O View FIGURE 6 )

urn:lsid:zoobank.org:act:

Type material. Holotype P ♂, AUSTRALIA, Western Australia, North Dandelup, Foster Brook, Foster Brook , [32°30’S, 116°02’E], 11.vii.1990 (Edward) ( WAM) GoogleMaps . Paratypes, P ♂, Le/P ♀, Western Australia, North Dandelup R., 10.viii.1995 (Armstrong) ( ANIC); L head + ♂ genitalia, Seldom Seen Brook, 32°15'S 116°04'E, 20.viii.1982 (Edward) ( WAM) GoogleMaps .

Description. Male (n=1–2, teneral): Thorax brown, without distinct vittae; legs brown, without banding. Wing membrane unmarked. Setae of TIX fine, medium-lengthed, arranged in +/- horseshoe shape. Gonostylus narrow at junction with gonocoxite, which bears only simple setae. Superior volsella proximally with 4–5 long setae in mi- crotrichiose region, posterior setose projection well developed ( Fig. 2L View FIGURE 2 ) medially-directed apically rounded digitus devoid of microtrichia, with one pectinate scale, 3–4 simpler setae nearer apex. Pseudovolsella low bearing 2 moderate-lengthed strong etae. Inferior volsella appressed basally to inner contour of gonocoxite and linked to distal part of superior volsella, with 5–6 pectinate scales and many long simple setae. Mensural features cannot be tabulated on the teneral males.

Female teneral, apparently as in male.

Pupa. Pale with yellow dorsal thorax, anterior wing sheaths and lateral apophyses on abdominal segments V–VIII; comb yellow. Cephalothorax almost smooth, with minor tuberculosity only along ecdysial line. Abdomen with continuous hook row on tergite II c. 40% of tergite width; conjunctival spinule bands complete on III and IV, on V weaker but continuous. Pedes spurii B absent, vortex strong. Abdomen with tergite II–VI with armament +/- rectangular, sparse, with anterior transverse band distinctive by density of spines—no stronger on II than remainder of tergites; TVII and VIII and sternites bare but tergal and sternal patterns difficult to interpret on pharates. LS setae on V–VIII 3, 4, 4, 5 on VIII more or less evenly spaced. Comb with 1 strong triangular tooth, 2–3 weaker posteriorly-directed spines. Anal lobe with 45–55 taeniae in biserial to partly multiserial row.

Larva. Head capsule pale yellow with narrow brown occipital margin, mandible golden yellow, mentum and inner mandibular teeth brown (innermost 4 th incompletely separated from mola). Clypeus ( Fig. 6O View FIGURE 6 ) c. 2× as wide as long, indented laterally, with clypeal setae strongly retracted. Inner margin of mandible with broad spine beside insertion of seta subdentalis and 3 serrations further towards base of mola. Each antennal segment shorter than that preceding; blade not extending to antennal apex. Ventromental plate diagnostically short, only 75% of mentum width. Mensural features as in Table 1 View TABLE 1 .

Etymology. The epithet derives from zeylandica , with which this species had been confused, combined with prefix ‘wa’ showing it is Western Australian.

Diagnosis. In the male genitalia of R. wazeylandica , uniquely in the genus, a solitary pectinate seta lies at the base of the digitus of the superior volsella.The cluster of 5–6 pectinate setae on the lobe of the superior volsella distinguishes from the otherwise similar and also Western Australian R. noongar that has only simple setae on the superior volsella.

The pupa of R. wazeylandica has the 3 posterior taeniate ( LS 2–4) setae on segment VIII clustered, in contrast to the more even spacing of these setae in R. azeylandica .

The larva resembles R. azeylandica in having contrasting darker mentum and mandible and antennal segment 3 shorter than the 2 nd. With an AR of 1.4–1.6, narrow postoccipital margin and short ventromental plates, the larva closely resembles that of R. noongar , another Western Australian species.

Remarks. The dorsal head sclerites, notably the clypeus ( Fig. 6F, 6I, 6O View FIGURE 6 ), varies enough to allow separation of unreared larvae of the 3 western Australian Riethia from each other and from other Australasian species. No genetic information is available for this taxon.

Distribution and ecology. Riethia wazeylandica is restricted to Western Australia in a limited area of karri and jarrah forested streams.