Chironomus Meigen, 1803

Namayandeh, Armin, Hudson, Patrick L., Bogan, Daniel L. & Hudson, John P., 2024, Chironomidae (Diptera: Insecta) of Alaska, USA, with descriptions of new species and a checklist, Zootaxa 5511 (1), pp. 1-95 : 75-76

Chironomus Meigen, 1803

Martin (2023) provided detail information on the Nearctic species of Chironomus . We have listed 16 named species of Chironomus and three based on cytotaxonomic methods mentioned in Martin (2023). There are also five unknown species in BOLD Systems ( Arctos 2023), which we refrained from listing as the Mitochondrial Cytochrome Oxidase I marker is not useful in separating the Chironomus species ( Proulx et al. 2013). As such, our listing is tentative but illustrates the diversity of Chironomus species in Alaska.

The Alaskan record of Chironomus (s.s.) acidophilus Keyl, 1960 is based on a BOLD Systems record of a female collected in Potter Marsh in Anchorage in mid-May by Dave Wartinbee and identified by Jon Martin. Thompson & Epler (2009) collected adults of Chironomus (s.s.) annularius sensu Strenzke, 1959 on Attu Island in mid-July. We collected Chironomus (s.s.) bifurcatus Wülker, Martin, Kiknadze, Sublette & Michiels, 2009 males around Peterson Creek near Juneau in late August, which represents a new faunistic record for Alaska. A species listed as Chironomus sp. 2 x in Martin (2023) that could be Chironomus (s.s.) decumbens Malloch, 1934 is listed from Harding Lake, southeast of Fairbanks. We verified the presence of C. decumbens in Alaska based on males we collected from the Yukon River delta in mid-July. We collected an adult of Chironomus (s.s.) staegeri sensu Townes 1945 from the Mendenhall Lake near Juneau in late August. Martin (2023) notes that Chironomus (s.s.) staegeri Lundbeck, 1898 and Chironomus (s.s.) fasciventris Malloch 1915 (junior synonym of C. staegeri sensu Townes, 1945 ) may be different species altogether. This is based on the caveat that specimens from Greenland are not the same as specimens found in the USA. Butler et al. (1980) reported Chironomus (s.s.) hyperboreus Staeger, 1845 from Utqiagvik, Watson et al. (1966) reported this species from Ogotorak Creek. Butler et al. (1980) found larvae of this species to be most common in smaller ice-wedge ponds and flooded grassy areas, which dried out in late summer and are rare in larger ponds near Utqiagivk. Chironomus (s.s.) longistylus Goetghebuer, 1921 was collected from a lake along the Dalton Highway on the south slope of the Brooks Range ( Martin 2023). Adults of Chironomus (s.s.) maturus Johannsen, 1908 were collected by Dave Wartinbee from Potter Marsh and identified by Jon Martin. Other records include a molecular identification from the Kenai National Wildlife Refuge by Bowser et al. 2020. Our records include material from Margaret Bay on Revillagigedo Island, a Glacier Bay National Park and Preserve wetland, and Peterson Creek and a stream near Lena Point in Juneau. These adults were collected in late April, early June, and mid-July.

Records of Chironomus (s.s.) pilicornis (Fabricius, 1794) are from Ogotorak Creek ( Watson et al. 1966) and Utqiagvik in Martin (2023) and Butler (1980b). Butler (1980b) found this species more abundant in the center of tundra ponds rather than the Carex covered shoreline. Butler (1982b) described Chironomus (s.s.) prior from tundra ponds in the Prudhoe Bay area and we collected adults near Margaret Lake on Revillagigedo Island in mid-April. Chironomus (s.s.) riparius Meigen, 1804 specimens were collected on Attu Island by Thompson & Epler (2009) and by Lougheed et al. (2011) and Butler et al. (1980) around Utqiagvik. Chironomus (s.s.) sanctipauli Sublette, 1966 is the new name for Chironomus (s.s.) conformis Malloch, 1923 which was collected from the Pribilof Islands and more recently by Watson et al. (1966) from Ogotorak Creek. We collected this species from Margaret Lake in mid-April (see Martin 2023). Butler (1982b) described Chironomus (s.s.) tardus from tundra ponds in the Prudhoe Bay area. We collected adult males of this species from Peterson Creek in the Juneau area in mid to late August. Chironomus (s.s.) tentans Fabricius, 1805 was listed from Alaska as Chironomus (s.s.) granivalva in Shilova & Shobanov (1996) and in Butler et al. (1980) from tundra ponds near Utqiagvik and from Potter Marsh in Anchorage ( Martin 2023). Martin (2023) also notes there is some doubt that this species occurs in North America, but the data of Acton (1962) suggests that Alaskan populations should still be considered as C. tentans . Chironomus (s.s.) trabicola Shobanov, Wülker & Kiknadze, 2002 has been reported from tundra ponds near Prudhoe Bay ( Martin 2023). Chironomus (s.s.) viridulus in Watson et al. (1966) is a nomen dubium.

Martin (2023) lists several unnamed morphospecies of Chironomus , including Chironomus sp. Le1 by Kiknadze et al. (1996) based on larval specimens identified by unique cytology collected from ponds near Utqiagvik. Chironomus sp. Anchorage and Chironomus sp. 4 M based on larvae with unique cytology were collected from Potter Marsh ( Martin 2023). We collected a unique species of Chironomus from Peterson Creek near Juneau in early August that appears to be undescribed. However, molecular analysis of polytene chromosomes in the fourth instar larvae is necessary to erect this as a new species. For now, we named this species Chironomus sp. 5 x ( Fig. 11J ; see also Martin 2023).

Figures

FIGURE 11. The new Nearctic faunistic records of Alaskan Chironomidae II; Parorthocladius lazovskiensis Makarchenko & Makarchenko, 2015 male (A); Stilocladius kurobekeyakia (Sasa and Okazawa, 1992) male (B–C); Thienemanniella acuticornis (Kieffer, 1912) larva (D–F); Thienemanniella chuzeduodecima Sasa, 1984 male (H–I); Chironomus sp. 5X male (J); Stempellinella depilisa Guo & Wang, 2007 male (K–M). A. hypopygium. B. hypopygium. C. wing. D. abdominal segments. E. antenna. F. mentum. G. posterior parapod subbasal setae. H. antenna. I. hypopygium. J. hypopygium. K. hypopygium. L. anal point. M. wing. Scale bars are 50 µm.