Riethia chilensis, Andersen & Malla & Giłka, 2024

Andersen, Trond, Malla, Annui & Giłka, Wojciech, 2024, Two new species of Riethia Kieffer, 1917 from Chile and Ecuador (Chironomidae: Chironominae, Pseudochironomini), Zootaxa 5448 (4), pp. 499-507 : 500-503

publication ID

https://doi.org/ 10.11646/zootaxa.5448.4.3

publication LSID

lsid:zoobank.org:pub:97D81822-3B9A-4A25-99ED-F8DC6AE1436B

DOI

https://doi.org/10.5281/zenodo.11232208

persistent identifier

https://treatment.plazi.org/id/6FB58B1E-775B-4B10-8628-51E06C8D5675

taxon LSID

lsid:zoobank.org:act:6FB58B1E-775B-4B10-8628-51E06C8D5675

treatment provided by

Plazi

scientific name

Riethia chilensis
status

sp. nov.

Riethia chilensis sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:6FB58B1E-775B-4B10-8628-51E06C8D5675

( Figs 1A–C View FIGURE 1 , 2A–C View FIGURE 2 )

Type material. Holotype adult male (slide mounted under five coverslips), CHILE, Los Rios Region, Valdivia Province, Panguipulli, El Desague , Lago Riñihue , Limnological field station, 39.774388°S 72.453394°W, 115 m a.s.l., 5.xi.1969, leg. F. Reiss ( ZSM) GoogleMaps . Paratypes, 58 adult males as holotype ( ZSM, ZMBN) .

Etymology. The epithet, chilensis , is used as an adjective and meaning “from Chile ” in reference to the country of origin of the holotype.

Diagnostic characters. Riethia chilensis differs from its close relative, R.truncatocaudata , by uniformly coloured legs, without bands, and curved, stout superior volsellae without microtrichia dorsally. A light brown abdomen, with darker anterior bands on the tergites, and a superior volsella without microtrichia are the characters that separate R. chilensis from the second new species described here (see below). Both new species + R. truncatocaudata can be separated from all other Riethia View in CoL by having the inferior volsella strongly bent dorsally, with apical part subtriangular and dorsally covered with broad, flattened, apically fringed setae. See also the diagnosis for the second species.

Description. Adult male (n = 5)

Body size and proportions. Total length 5.21–5.71, 5.44 mm. Wing length 3.03–3.23, 3.09 mm. Total length / wing length 1.70–1.88, 1.76. Wing length / length of profemur 2.30–2.47, 2.35.

Colouration. Head pale brown with brown pedicel; thorax brown with pale brown vitae, scutellum, and posterior part of preepisternum; legs brown without darker bands ( Fig. 1B View FIGURE 1 ); abdominal tergites brown in anterior ¼, light brown in posterior ¾ ( Fig. 1C View FIGURE 1 ). Wing hyaline ( Fig. 1A View FIGURE 1 ).

Antenna. AR 1.78–2.04, 1.91. Terminal flagellomere 760–920, 846 µm long.

Head. Temporal setae 31–36, 34, bi- to tri-serial. Clypeus with 18–22, 20 setae. Tentorium 193–221, 205 µm long, 57–66, 61 µm wide. Stipes 199–221, 209 µm long, 12–16, 14 µm wide. Palpomere lengths (in µm): 52–64, 58; 92–104, 97; 164–200, 181; 228–252, 237; 256–332, 289. Third palpomere with 4–7, 5 sensilla clavata subapically, longest about 29 µm long.

Thorax. Antepronotum with 8–12, 9 ventrolateral setae. Acrostichals strong, 9–16, 12, in double row; dorsocentrals 11–17, 14 in single row; prealars 3–5, 4; supraalar 1. Scutellum with 14–16, 15 setae in partly double row.

Wing ( Fig. 1A View FIGURE 1 ). VR 1.06–1.12, 1.08. Brachiolum with 3 setae; R with 23–31, 28; R 1 with 19–24, 21; R 4+5 with 32–39, 36 setae; other veins and membrane bare. Squama with 10–15, 13 setae.

Legs. Spur of fore tibia 76–86, 81 µm long; spurs of mid tibia 58–69, 62 µm and 75–94, 82 µm long; spurs of hind tibia 72–88, 79 µm and 89–115, 99 µm long. Width at apex of fore tibia 75–94, 82 µm; of mid tibia 63–75, 69 µm; of hind tibia 72–79, 76 µm. Lengths and proportions of legs as in Table 1 View TABLE 1 .

Hypopygium ( Figs 2A–C View FIGURE 2 ). Tergite IX with straight posterior margin, with 17–27, 23 setae medially and 34–51, 42 setae in two to three rows along posterior margin. Laterosternite IX with 6–9, 8 setae. Phallapodeme 154–186, 166 µm long; with 41–58, 47 µm long, narrow, curved oral projection. Transverse sternapodeme straight, 69– 97, 79 µm long, with comparatively long oral projections. Gonocoxite 242–275, 257 µm long. Superior volsella stout, curved, with long, narrowly triangular apex projecting anteromedially, 80–89, 86 µm long, 23–32, 26 µm wide medially, with 5 weak dorsal setae, without microtrichia. Inferior volsella strongly bent dorsally with bluntly subtriangular apical part, 54–69, 60 µm long, 37–44, 40 µm wide, with microtrichia, marginal setae, and 29–36, 32 broad flattened, apically fringed setae ( Fig. 2A View FIGURE 2 1 View FIGURE 1 ) dorsally. Pseudovolsella consisting of low, bluntly triangular tubercle, with 2–3, 3 curved setae, longest seta 48–59, 55 µm long. Gonostylus 176–209, 194 µm long. HR 1.16– 1.56, 1.33. HV 2.74–2.96, 2.80.

Female and immature stages unknown.

Distribution. The species was collected resting on bushes and other vegetation near a lakeshore in southern Chile.

ZSM

Bavarian State Collection of Zoology

ZMBN

Museum of Zoology at the University of Bergen, Invertebrate Collection

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Diptera

Family

Chironomidae

SubFamily

Chironominae

Tribe

Pseudochironomini

Genus

Riethia

GBIF Dataset (for parent article) Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF