Nymphomyia cf. rohdendorfi Makarchenko, 1979

Yanygina, L. V. & Makarchenko, E. A., 2023, First finding of the archaic nymphomyiid flies (Diptera: Nymphomyiidae) in the Altai Mountains of Russia, Far Eastern Entomologist 478, pp. 23-28 : 24-27

Nymphomyia cf. rohdendorfi Makarchenko, 1979

Figs 1–4

MATERIAL. Russia: Republic of Altai, Kosh-Agachsky District, Mukhor-Tarkhatinsky rural settlement: 6 larvae, Kuruk River ( Katun River basin), alt. 2273 m, 49.58278 N, 88.42767 E, 28.V 2022 ; 1 larva, the same data except Kalanegir River ( Katun River basin), alt. 2200 m, 49.64237 N, 88.47350 E, 28.V 2022 leg. L. Yanygina.

DESCRIPTION. LARVA (n=7). Total length 1.7–1.9 mm. Head length 164–168 µm, head width 88–92 µm.

Coloration. White or greyish, head pale brown, brown.

Antenna ( Fig. 2 ). Basal antennal segment 41–44 µm long, pointed antennal seta 18–21 µm long, flat antennal seta 10–13 µm long.

Mandible ( Fig. 4 ). With 7 teeth, inner seta composed of 6–8 pinnate branches, seta subdentalis wedge-shaped.

Mentum ( Fig. 1 ) Median tooth shorter than adjacent lateral teeth and with two pairs of lateral serrations; lateral teeth without lateral serrations; notch between lateral teeth 1 and 2 as deep as notches separating other teeth; 4 pairs lateral teeth of more or less uniform size and shape; fifth pair slightly lower and wider than other lateral teeth.

Hypopharynx ( Fig. 3 ). Wide at the base, with a ridge of 8 long and narrow teeth at the apex, of which the extreme teeth are almost two times lower than the other teeth.

Abdomen. Typical for nymphomyiid larvae. Nine-segmented, segments I–VII and IX each with paired, elongate, eversible, ventral prolegs. Anal papillae of four thick, exsertile, digitiform lobes between procercus and anal prolegs; dorsal pair markedly larger than ventral pair.

COMMENTS. Nymphomyiid larvae are very similar of each other, but we bring the larva from Altai Mountains closer to that of N. rodendorfi and place it in the group of N. rohdendorfi species. This group is characterized by the presence in mentum lateral teeth which of more or less uniform size and shape while mentum of N. levanodovae group with first and second lateral teeth united basally, second tooth extended anteriorly beyond apices of others.

The localities of finds of nymphomyid larvae in Altai Mountains of Russia and pupal exuvia in Mongolia ( Hayford & Bouchard, 2012) are not far from each other ( Fig. 5 ) and most likely we are dealing with the same species that lives in mountain streams at altitudes of 1694–2798 m.

ECOLOGY

Nymphomyiid larvae were found in the moderately cold-water streams ( Fig. 6 ) (water temperature during sampling made up 11.0–11.9°С). In sampling sites, width of rivers Kuruk and Kalanegir was 14 and 20 m, respectively, and depth – 0.25 m. Bottom sediments were mainly formed by pebbles (50–65% of the bottom area). The studied waters were weakly alkaline (pH 8.1–8.4) and low-mineralized (0.09–0.12 ppt). The content of nutrients (below detection limits) and organic substances (BOD 5 0.54–0.86 mgO/dm 3) was low. Relatively high COD values (28–33 mgO/dm 3) were noted, probably, due to a partially waterlogged catchment area. Phytoplankton (concentration of chlorophyll a in water 0.5–1.2 mg /m 3) and phytoperiphyton (concentration of chlorophyll a in washouts from pebbles 8.4–13.8 mg /m 2) were low. Unlike most species recorded in aquatic moss mats, nymphomyids in rivers Kuruk and Kalanegir lived on moss-free stones, similar to N. alba in Japanese rivers ( Takemon & Tanida, 1994). Perhaps, the absence of moss mats and poor periphyton development determined low abundance of nymphomyiids in the studied rivers of the Russian Altai.

A common feature of the nymphomyiids ecology of the Russian and Mongolian Altai is their habitat in streams running through free from tree vegetation landscapes, in contrast to most other species recorded in rivers with well-developed coastal vegetation ( Harper & Lauzon, 1989; Saigusa et al., 2009; Hayford & Bouchard, 2012; Makarchenko et al., 2014).

Figures

Figs 1–4. Larva of Nymphomyia cf. rohdendorfi Makarchenko. 1 – mentum; 2 – antenna; 3 – hypopharinx; 4 – mandible.

Fig. 5. Finding sites of Nymphomyiidae in Altai Mountains. 1, 2 – Nymphomyia cf. rohdendorfi Makarchenko in Russia (original data); 3–5 – Nymphomyia sp. in Mongolia (after Hayford & Bouchard, 2012).

Fig. 6. Locality of Nymphomyia cf. rohdendorfi Makarchenko. Republic of Altai, Kosh- Agachsky District, Mukhor-Tarkhatinsky rural settlement, Kalanegir River (Katun River basin), alt. 2200 m. (Photo by A.V. Kotovshchikov).