New Records of Chironomidae (Insecta: Diptera) from Mongolia with Review of Distribution and Biogeography of Mongolian Chironomidae

Fourteen species of Chironomidae (Diptera) are recorded for the first time from the Hovsgol Nuur region, Mongolia, increasing the total number of chironomid species from this country to 166 (Table 1). Two major studies have contributed the most data on distribution of Chironomidae in Mongolia. The first study, summarized by Kozhova et al. (1994) and Erbaeva and Safronov (in press), was based on 20 years of research on Hovsgol Nuur, an ancient lake in Northern Mongolia. The second study, by Sasa and Suzuki (1997), described many new species and listed many species of Chironomidae from Central and Southwestern Mongolia. In addition, Reiss (1971) described and listed species of Chironomidae collected from sites throughout the country and Hayford and Ferrington (in press) studied the distribution of chironomids in Hovsgol Nuur. The current valid name-author-date and biogeographic region distribution for Mongolian Chironomidae were obtained from Ashe and Cranston (1990) and are listed with the Mongolian distribution for each species in Table 1. Of the 118 species of Chironomidae listed from the Hovsgol Nuur Region, fourteen are new records for Mongolia (Table 1). Collections were made during June and July of 1995-1997 as part of a joint United States, Mongolian, and Russian expedition to the Hovsgol Nuur Region. Adults were collected using malaise traps and sweep nets and pupal exuviae were collected using methods modified from Ferrington (1987). Eight of the fourteen newly recorded species, Ablabesmyia nr. cinctipes (Johannsen), Cricotopus (Cricotopus) cylindraceus (Kieffer), Heterotrissocla dius subpilosus (Kieffer), Parakiefferiella nr. smolandica (Brundin), Psectrocladius (Psectrocladius) schlienzi Wiilker, Psectrocladius (Psectrocladius) sordidellus (Zetterstedt), Dicrotendipes lobiger (Kieffer), and Dicrotendipes septimacullipennis (Goetghebuer) were collected from the shore of Modon Hui, an island in Hovsgol Nuur. Six species, Krenosmittia camptophleps (Edwards), Parametriocnemus boreoalpinus Gouin, Rheosmittia spinicornis (Brundin), Saetheria reissi Jackson, Cladotanytarsus vanderwalei (Edwards), and Corynocera ambigua (Zetterstedt) were collected from sandy bottom streams flowing into Hovsgol Nuur. Most of the Chironomidae in Mongolia have a cosmopolitan distribution (Table 1). Forty-seven species have a Holarctic distribution, with some additionally found in the Oriental and Neotropical regions. Seventy-nine species have a Palaearctic distribution, with some of these additionally found in the Oriental, Afrotropical and Australasian regions. Species with a Palaearctic distribution tended to have a West Palaearctic distribution, with very few species having an East Palaearctic distribution. This distribution is similar to that of caddisflies reported by Morse et al. (in press), with the exception that most caddisflies were also found in the nearby East Palaearctic region. Nearly 20% of the species of Chironomidae found in Mongolia are endemic, with most described by Sasa and Suzuki (1997). However, note that specific type localities are not clear. Thus, it is uncertain where some species were originally collected. Distribution records for species within Mongolia come primarily from the Hovsgol Nuur region or from sites close to Ulaanbaatar. Currently, two studies are underway to collect Chironomidae in central (Selenge River basin) and western (saline lake district) Mongolia, which should vastly increase the known species of Chironomidae from this country.