Cricotopus, Wulp, 1874

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 : 56-57

Cricotopus v. d. Wulp, 1874

The genus Cricotopus along with Orthocladius is the most speciouse genus in Alaska. We accounted for 24 species, including 5 unknown immatures. To accommodate a discussion of this genus we used the classification used by Hirvenoja (1973), accompanied by nomenclature of Ashe & O’Connor (2012), and the recent synonymy by Cranston & Krosch (2015).

Nine of the historical records from Alaska are accounted for in Oliver & Dillon (1988). These include Cricotopus (s.s.) beringensis Oliver & Dillon, 1988 ; Cricotopus (s.s.) bicinctus (Meigen, 1818); Cricotopus (s.s.) ephippium (Zetterstedt, 1838) (recorded as Cricotopus (s.s.) humeralis (Zetterstedt, 1838) by Watson et al. (1966); Cricotopus (Isocladius) laricomalis Edwards, 1932 , Cricotopus (s.s.) lestralis (Edwards, 1924) , Cricotopus (Isocladius) ornatus (Meigen, 1818) , Cricotopus (Isocladius) sylvestris (Fabricius, 1794) , Cricotopus (s.s.) tibialis (Meigen, 1804) , and Crictopus (s.s.) trilobus Oliver & Dillon, 1988 . Many of the specimens described by Oliver and Dillon were collected in the Point Barrow area by P.D. Hurd and Malcolm Butler in the 1950s and 1970s, respectively, and along the Naknek River near King Salmon by W.R. Mason in the 1960s.

The Cricotopus (s.s.) tibialis group in Alaska contains six species: C. beringensis , C. ephippium , C. lestralis , Cricotopus (s.s.) polaris Kieffer, 1926 , C. tibialis , and C. trilobus . Adults of C. beringensis were described by Oliver & Dillon (1988) from material supplied by Malcolm Butler from Prudhoe Bay. Watson et al. (1966) reported C. ephippium in the Ogotoruk Valley in Western Alaska. However, Oliver & Dillon (1988) found the record to be problematic since the associated material is not available and Watson et al. (1966) could have misidentified C. lestralis as C. ephippium . Specimens identified from Point Barrow and collected by P.D. Hurd in late July 1953 were identified as C. lestralis by Oliver & Dillon (1988). Both species have a northern distribution; however, for now, their records, at best, should be considered doubtful. We collected C. polaris adults from Tangle River in mid-August and Twin Lakes in Juneau in mid-July, and a male pupa from the Yukon River delta. This is a new faunistic record for Alaska. Records of C. tibialis are from Pt. Barrow and Naknek River ( Oliver & Dillon 1988) in early to mid-July and our collection from the Tangle River ( Fig. 9N ) in mid-August. C. tibialis larvae in the Nearctic have only been found in permanent ponds where they are usually associated with filamentous algae in Carex stands. Cricotopus (s.s.) trilobus was described by Oliver & Dillon (1988) from material collected around Utqiagvik by P.D. Hurd in mid to late July 1952 and provisionally assigned to the tibialis group.

We collected adults of Cricotopus (s.s.) patens Hirvenoja, 1973 belonging to the cylindraceus group along Peterson Creek near Juneau, in early August. Larvae in the C. cylindraceus group were also collected in two small meandering streams in the Arctic Coastal Plain near Atqasuk (AWQMS 2005).

We collected adults and immatures of Cricotopus (s.s.) bicinctus (Meigen, 1818) from Otter Creek in the Anchorage area in early June and males were collected from the Naknek River in early August ( Oliver & Dillon 1988). We collected larvae from Grey’s, Goose, Caswell, Lucille and Meadow Creeks in the Mat-Su Valley, the South Fork of Little Campbell Creek in Anchorage, tributaries to the South Fork Koktuli River in Southwestern Alaska, and Skull and Harriet Hunt Creeks near Ketchikan. This species is often associated with filamentous algae ( Darby 1962, Tokeshi 1986). Larvae of Cricotopus (s.s.) pilosellus Brundin, 1956 were collected from Big Lake on St. Mathew Island, a new faunistic record for Alaska. Hirvenoja (1973) found them living in shallow, sometimes brackish water. During strong storms, Big Lake with only a narrow barrier separating it from the Bering Sea is probably breached quite often. We collected adults of Cricotopus (s.s.) trifascia Edwards, 1929, from the Tangle River in mid-August. LeSage & Harrison (1980) found adults of this species swarming about 11 m from the stream edge at 2–3 m above the ground. Their emergence occurred in southern Ontario in May to June, and September to October. We collected larvae of Cricotopus (s.s.) vierriensis Goetghebuer, 1935, from East Fork Moose River on the Kenai Peninsula. This is a new faunistic record for Alaska. This species seems most common in small rivers and streams ( Moller Pillot 2014). We collected Cricotopus (s.s.) elegans Johannsen, 1943 larvae from the Kanuti Lake outlet ( Fig. 9O ) in the Kanuti National Wildlife Refuge, also a new faunistic record for Alaska.

Larvae belonging to Cricotopus festivellus group were collected in small lakes along the Arctic Coastal Plain (AWQMS 2005), and from Lily Lake in Haines and Harriet Hunt Lake in Ketchikan. We collected an adult male of Cricotopus (Cricotopus) albiforceps (Kieffer, 1916) from Auke Lake outlet in Juneau in early August and larvae from Little Meadow Creek near Wasilla. We collected adult males of Cricotopus (Cricotopus) flavocinctus (Kieffer, 1924) from the Yukon River delta and Twin Lakes in Juneau in mid-July. Both taxa represent new faunistic records for Alaska.

Cricotopus (s.s.) tremulus (Linnaeus, 1758) adults have been identified through molecular DNA barcoding of materials collected from the Kenai National Wildlife Refuge ( Bowser et al. 2020). We have also collected adults of C. tremulus from the Tangle River area in mid-August and larvae from Glacier Bay National Park and Preserve, and several streams in Mat-Su Valley and Anchorage area including Chester, South Fork Chester, Cottonwood, Deception, Meadow and Wasilla Creeks. All our other records are larvae reported in Arctos from lakes and streams in the Northern Coastal Plain, St. Matthew Island and from a tributary to the Kotuli River. We also collected the larvae of Cricotopus (s.s.) curtus Hirvenoja, 1973, in the tremulus group, from Spike Creek on Revillagigedo Island in a drift net associated with a mesocosm experiment. Several unknown larvae and a pupa of Cricotopus (Cricotopus) were also collected from the Mat-Su Valley.

Adults of Cricotopus (Isocladius) laricomalis Edwards, 1932 , were collected from ponds along the Arctic Coastal Plain in early to mid-July ( Oliver & Dillon 1988). The larvae of this species have been collected from 15 coastal lakes and ponds along the Northern Alaska Coast (AWQMS 2005) and from the Koyukuk River ( Arctos 2023). We collected a male from Yukon River delta in mid-July. Oliver & Dillon (1988) note that this species occurs mainly in permanent ponds, has a two-year life cycle, and mates in swarms, mated pairs fly to the ground, where they remain in copula for up to one hour. A species of Cricotopus (Isocladius) near perniger (Zetterstedt, 1850) has been reported from northern tundra ponds by both Butler et al. (1980) and Lougheed et al. (2011). C. perniger has mainly been collected in northern lakes in Europe ( Moller Pillot 2014). There are two species in the Cricotopus sylvestris group collected near Point Barrow. Adults of Cricotopus (Isocladius) ornatus (Meigen, 1818) and Cricotopus (Isocladius) sylvestris (Fabricius, 1794) were collected near Point Barrow from mid to late July ( Oliver & Dillon 1988). The larvae of both species were collected from the Miller Creek watershed on the Kenai Peninsula based on DNA bar code information ( Bowser et al. (2020). Oliver & Dillon (1988) mention that it is difficult to distinguish the members of this group, especially adults. C. sylvestris is known to deposit large masses of communal eggs in lakes and ponds ( Nolte 1993). This species is also known to occur in hot springs ( Tuxen 1944) and brackish water ( Parma & Krebs 1977) and is associated with macrophytes ( Darby 1962; Mackey 1977). Oliver & Dillon (1988) note that C. ornatus is often associated with coastal and inland saline waters. We collected adults of Cricotopus (Isocladius) tricinctus (Meigen, 1818) in early August from the Tangle River, Deadman Lake campground in Tetlin National Wildlife Refuge, the Yukon River delta, and Peterson Creek where it flows into Salt Creek in Juneau. Bowser et al. (2020) also collected it from the Miller Creek watershed on the Kenai Peninsula. We collected larvae, pupae, and males of Cricotopus (Isocladius) trifasciatus (Meigen, 1810) from the Yukon River delta in late July, a new faunistic record for Alaska.

We collected three species in the subgenus Paratrichocladius Thienemann, 1942 . Adult males of Cricotopus (Paratrichocladius) rufiventris (Meigen, 1830) were collected near the Tangle River in mid-August, and a male near Mendenhall Lake in late May, representing a new Alaska faunistic record. We collected all life stages of Cricotopus (Paratrichocladius) scaturigineus ( Makarchenko & Makarchenko, 2014) from the Alsek River, Glacier Bay National Park and Preserve in early September and from the Yukon River delta in mid-July. Adult and immature characteristics fall within Makarchenko & Makarchenko ’s (2014) description ( Fig. 10E–G ). This species has only been reported from springs of the Amur River basin, the Jewish Autonomous Region, Bidzhan River basin. This is the first faunistic record of this species from the Nearctic. We collected two males of Cricotopus (Paratrichocladius) skirwithensis (Edwards, 1929) from the Yukon River delta in mid-July. This is a new Alaskan faunistic record. We also collected larvae of C. ( Paratrichocladius ) from Meadow and Little Meadow Creeks in the Matsu Valley, and Deep Creek on the Kenai Peninsula.

Figures

FIGURE 9. Some of the study’s collection sites and habitats of Chironomidae in Alaska. A. Turner Lake, near Juneau. B. Bartlett River in Glacier Bay National Park and Preserve. C. Alaska, USA and Yukon Territory, Canada international boundary. D. Auke Lake outlet in Juneau. E. Rachael Lake near Bettles. F. Spike Creek on Revillagigedo Island. G. Auke Lake in Juneau. H. Hebert River near Juneau. I. Nugget Falls, in Juneau. J. Forested bog near Eagle crest Ski Area, Douglas Isand. K. Creek outlet at Margaret Bay on Revillagigedo Island. L. Mount Roberts (foreground) in Juneau. M. A snow-melt stream (arrows) on Thunder Mountain, Juneau. N. Tangle River near Paxon. O. Kanuti Lake outlet in Kanuti National Wildlife Refuge. P. Fish Creek on Douglas Island. Q. Antler River near Juneau. R. Harbor Mountain, Sitka. S. Observing Thalassosmittia marina (Saunders, 1928) larvae in intertidal rock pools near Lena Point, Juneau. T. Larvae of T. marina (arrows) inhabiting a rock pool in the upper tidal zone and feeding on periphytic algae near Lena Point, Juneau. U.A tundra lake east of King Salmon. V. Swarm of Corynocera oliveri group adults on a tundra lake east of King Salmon.

FIGURE 10. The new Nearctic faunistic records of Alaskan Chironomidae I. Lappodiamesa vidua (Kieffer, 1922) larva (A– C); Acamptocladius submontanus (Edwards, 1932) male (D); Cricotopus (Paratrichocladius) scaturigineus (Makarchenko & Makarchenko, 2014) male, pupa, larva (E–F); Eukiefferiella clypeata Kieffer, 1922 male, pupa (H–J); Eukiefferiella gracei (Edwards, 1929) male, pupa (K–M); Heleniella ornaticollis (Edwards, 1929) male (N); Metriocnemus shoulcarus Sasa, 1989 male (O–P). Paracladius omolonus Makarchenko & Makarchenko, 2006 (Q). Parakiefferiella rara Makarchenko & Makarchenko, 2007 male, pupa (R–S). A. Mentum. B. premandible. C. procercus. D. hypopygium. E. hypopygium. F. tergites II–V. G. mandibles, mentum, labrum. H. hypopygium. I. tergites II–V. J. thoracic horn. K. hypopygium. L. tergites II–V. M. thoracic horn. N. hypopygium. O. antenna. P. hypopygium. Q. hypopygium. R. hypopygium. S. tergites VI–IX. Scale bars are 50 µm.