Parachironomus Lenz from China and Japan (Diptera, Chironomidae)

Abstract Members of the genus Parachironomus Lenz known from China and Japan are revised, and a key to their male adults is given. Parachironomus poyangensis sp. n. is described in this life stage. Parachironomus frequens (Johannsen) and Parachironomus monochromus (van der Wulp) are recorded from China for the first time, thus are redescribed from Chinese specimens. Parachironomus kamaabeus Sasa & Tanaka and Parachironomus toneabeus Sasa & Tanaka are new junior synonyms of Parachironomus frequens. Three Chinese or Japanese species formerly placed in Parachironomus are transferred to other genera, resulting in the new combinations Cryptochironomus inafegeus (Sasa, Kitami & Suzuki), Demicryptochironomus (Irmakia) lobus (Yan, Sæther, Jin & Wang), and Microchironomus lacteipennis (Kieffer). Chironomus sauteri Kieffer, Parachironomus kisobilobalis Sasa & Kondo and Parachironomus kuramaexpandus Sasa are removed from Parachironomus; the last of these three denotes a valid species of uncertain generic placement, the first two are nomina dubia.


Introduction
The name Parachironomus was proposed by Lenz (1921) for a genus concept based on larval and pupal characters. Edwards (1929) gave the first brief diagnosis for male imagines. Townes (1945) treated Nearctic species which are now considered as Parachironomus in "Harnischia (Harnischia)", but his classification and nomenclature of Chironomini were very different from those in use today (e.g. Cranston et al. 1989;Makarchenko et al. 2006;Saether and Spies 2013). However, Townes' designation of Chironomus cryptotomus Kieffer, 1915 as the type of Parachironomus has been accepted as formally valid, even though the taxonomic identity of that species is uncertain (C. cryptotomus Kieffer is a nomen dubium). Among the known genera in the Harnischia group, the genus Parachironomus is closer to Demicryptochironomus Lenz (1941); it is distinguished from the later in having long superior volsella with 2-3 distal setae usually arising from distinct pits, inferior volsella with blunt or pointed caudal projection, while in Demicryptochironomus usually no the setal pits of superior volsella and inferior volsella reduced or absent. Freeman and Cranston (1980) synonymized Kribiocryptus Kieffer, 1921and Nilomyia Kieffer, 1921under Parachironomus Lenz, 1921. However, Spies and Saether (2004) showed that any name available from Kieffer (1921b, published in June) would take precedence over any name available from Lenz (1921, October). In this situation, using Parachironomus as a valid name could comply with the current rules of nomenclature (ICZN 1999) only if a special ICZN ruling were to effect an exemption from priority in this case, or if Kribiocryptus and Nilomyia are no longer treated as synonymous with Parachironomus. The latter classification has been adopted by Saether and Spies (2013), and is followed here. Lehmann (1970) revised 17 European species and gave a generic diagnosis and key to species. Spies et al. (1994) revised members of the genus from the Neotropical Region, and modified the generic definition. Later, Parachironomus supparilis (Edwards, 1931) was split in three species: P. longistilus Paggi, 1977, P. supparilis (Edwards), and P. valdiviensis Spies (Spies 2008). Spies (2000) studied the Palaearctic P. monochromus (van der Wulp) and the Holarctic P. tenuicaudatus (Malloch) in all stages, and presented a provisional key to adult males from Nearctic Region. Hashimoto et al. (1981) placed six species from Thailand in Parachironomus: P. apicalis (Kieffer), P. calopunctus Hashimoto, P. truncatus Hashimoto, P. nakhonphanomensis Hashimoto, P. tener (Kieffer), and P. trisetifer Hashimoto). However, if the partially incomplete published descriptions are correct, then all of these forms except possibly P. calopunctus obviously fall outside of the current diagnosis of Parachironomus. Moreover, the corresponding material is either lost or inaccessible. Under these circumstances, no species proposed in Hashimoto et al. (1981) is treated as valid in Parachironomus in the present work. Maheshwari and Agarwal (1993) published a Parachironomus agraensis from India, but insufficient description and inaccessible type material (M. Spies, pers. comm.) render this yet another nomen dubium in Chironomini. Kikuchi and Sasa (1990) described a P. tobaquartus from Indonesia, but several hypopygial features of that species clearly rule out placement in Parachironomus. Cryptochironomus lacteipennis Kieffer and C. sauteri Kieffer were listed in Parachironomus by Sublette and Sublette (1973), along with Chironomus primitivus Johannsen. However, the assignment of genus names used in that work does not match that of today (for example, "Parachironomus" included Microchironomus Kieffer). Moreover, the original description of C. sauteri treats the adult female only; thus the name could not possibly be interpreted by Sublette and Sublette or any recent author without examination of the syntypes (at SDEI, Müncheberg, Germany). Makarchenko et al. (2005) listed nine species from the Russian Far East: P. biannulatus (Staeger), P. forceps (Townes), P. frequens (Johannsen), P. gracilior (Kieffer) [sub P. arcuatus (Goetghebuer)]. P. monochromus (van der Wulp), P. paradigitalis Brundin, P. parilis (Walker), P. pseudovarus Zorina), and P. vitiosus (Goetghebuer); Zorina in Makarchenko et al. (2006) keyed eight of these species but omitted P. forceps. From 1985, Sasa and various co-authors, and Kobayashi and Suzuki (1999 recorded 11 species from Japan: P. gracilior (Kieffer) (Kruseman) (which might also be P. mauricii (Kruseman) or an unnamed species), and P. tamanipparai (this belongs to Saetheria Jackson; M. Spies, pers. comm.). Based on the present examinations, only fpur or five true Parachironomus species appear to be known from Japan: P. frequens (Johannsen), P. gracilior (Kieffer), P. monochromus (van der Wulp), and P. swammerdami (Kruseman); P. acutus (Goetghebuer) is only provisionally placed in the genus at this time. Wang et al. (1977) recorded Cryptochironomus arcuatus Goetghebuer, 1919 (= P. gracilior (Kieffer, 1918)) and Cryptochironomus primitivus Johannsen from Hubei Province, China. Wang (2000) listed both species in the genus Parachironomus. However, Cryptochironomus primitivus Johannsen has been treated as a synonym of Microchironomus tener (Kieffer) since Saether (1977). Wang and Ji (2003) recorded Parachironomus arcuatus (= P. gracilior) in Oriental China (Fujian Province). In addition, Wang (2000) recorded Parachironomus varus (Goetghebuer) from Tianjin, but upon rechecking the specimen we are correcting that identification to P. gracilior. Parachironomus lobus Yan, Saether, Jin & Wang was recorded by Yan et al. (2008b) from Hainan Province. According to an examination of type specimens by M. Spies, the species should be placed in the genus Demicryptochironomus.
Based on the known descriptions and material from China and Japan, the genus is reviewed, and one new species is described in the adult male stage. A key to adult males from China and Japan is provided.

Material and methods
The material examined was mounted on slides following the procedure outlined by Saether (1969). The morphological nomenclature follows Saether (1980) with the additions and corrections given by Saether (1990). Measurements are given as ranges followed by the mean when more than three specimens were measured, followed by the number measured (n) in parentheses.
Type material studied is housed in the following institutions: Wang collection, Department of Biology, Life Science College, Nankai University, Tianjin, China (BDN); Sasa collection, National Science Museum, Tokyo, Japan (NSM).
Remarks. Sasa and Tanaka (1999) described Parachironomus toneabeus from Japan based on material collected at Kamakura Bridge, Ino River, Gunma Prefecture on 21 August 1998. The sample number was given as "391: 45-47". Sasa and Tanaka (2001) proposed P. kamaabeus according to material collected at Taisho Bridge, Tone River, Gunma Prefecture on 1 July 1999. However, the number of the specimen is also "391: 45-47". Based on the type specimens and the original descriptions and figures, we place both P. toneabeus and P. kamaabeus as new junior synonyms of P. frequens (Johannsen), due to distinct matches in leg color, shapes of the anal point, superior volsella and gonostylus, and the shoulder-like tergite IX margin.
Distribution. The species is widely distributed in the Palaearctic and extends into the Oriental Region (Saether and Spies 2013). It occurs in China and Japan.
Remarks. The synonymy between P. gracilior and P. arcuatus was accepted in the past already (e.g. by Goetghebuer 1921a, Lenz 1938); thus we do not present it as a 'new synonymy' here. The holotype of Chironomus gracilior Kieffer (at SDEI) and non-type specimens identified as Tendipes monotomus by Kruseman (1933) have been examined by M. Spies, and found to be conspecific beyond any doubt (M. Spies, pers. comm.).
Distribution. Palaearctic (Spies 2000). It also is recorded from Palaearctic China and Japan. The record for China is new.
Diagnostic characters. The new species is distinguished by the following combination of characters: body size small, thorax and abdomen yellowish green, wing cells without setae, mid and hind tibiae each with single spur, anal point nearly parallelsided, superior volsella elongate digitiform, without distal swelling or projection, gonostylus nearly straight and of about even circumference throughout.
Coloration. Thorax yellowish green. Femora of front legs yellowish green with distal parts brown, tibiae and tarsomeres dark brown; mid and hind legs yellowish green with tarsomeres IV, V dark brown. Abdomen yellowish green.
Remarks. Kieffer (1921a) described the species in the genus Cryptochironomus, which at that time included many species now treated in several separate genera. Sublette and Sublette (1973) placed it in Parachironomus. Based on the original description, which describes the inferior volsella as absent, the superior volsella as long and slender, the gonocoxite straight in the proximal 1/3, curved in the distal 2/3, distally attenuated and terminating in an incurved hooklet, C. lacteipennis clearly belongs to Microchironomus and not to Parachironomus. The placement by Sublette and Sublette (1973), and the earlier one in "Tendipes (Parachironomus)" by Kruseman (1939), likely are due to the fact that those authors did not treat Microchironomus as a separate genus. Distribution. The species is recorded from Taiwan Province (Oriental China).
Remarks. Kieffer (1921c) described the species based on females only, and without figures. Tokunaga (1940) described males and females from Taiwan Province, but illustrated only the male superior volsella. Sublette and Sublette (1973) transferred the species to "Parachironomus", but their use of this genus name was different from that of today (i.e., included Microchironomus Kieffer). Sasa (1989) examined Tokunaga's specimens and considered them as belonging to either Cryptotendipes or Microchironomus, but suggested that the status and placement of C. sauteri should be reserved for future clarification. We agree with Sasa's opinion, but have been unable to examine any of the syntypes; therefore, the species is not included in the present key. Distribution. The species is known from Taiwan Province (Oriental China).
Material examined. JAPAN: Holotype of Parachironomus kisobilobalis Sasa & Kondo, 1994 (No. A 224: 49), male, Aichi Prefecture, Kiso River in dammed-up middle reach near Nagoya City, "emerged from a sample", 26. ii. 1992. Remarks. We have examined the holotype, but it was lacking the thorax, head except for antenna, tarsi of front legs, and half of the hypopygium. As the preserved parts do not suffice for placement of the species, we treat P. kisobilobalis as a nomen dubium. In any case, the original description calling the superior volsella "rod-like, with one apical seta and 4 short setae along inner margin" and the inferior volsella "semicircular, with 4 short marginal setae" (Sasa and Kondo 1994: 129; see also Figs 5i-5m) rules out that the species belongs to Parachironomus.
Distribution. The species has been recorded only from the type in a Palaearctic part of Japan.

Discussion
Among the many species previously reported in Parachironomus from Japan, only P. frequens, P. gracilior, P. monochromus, P. swammerdami, and possibly P. acutus (Original genus is Chironomus) are considered as valid records. Aside from the species treated in the present work, Parachironomus harunasecundus Sasa has been transferred to the genus Demicryptochironomus (Yan et al. 2008b); P. inageheus Sasa, Kitami & Suzuki, 2001 has been identified as a junior synonym of Demicryptochironomus ginzancedeus Sasa & Suzuki (Yan et al. 2008b). Parachironomus inafegeus Sasa, Kitami & Suzuki should be transferred to Cryptochironomus because of the prominent frontal tubercles, both superior and inferior volsellas carry long setae, the inferior volsella is completely covered by the superior volsella, and the gonostylus is short, rather broad and fused with the gonocoxite. Parachironomus tamanipparai (Sasa) was returned to Paracladopelma by Yan et al. (2008a), but the holotype (examined by M. Spies) and the published descriptions clearly show it to be a member of Saetheria (as recognized earlier, e.g. by Laville andReiss 1988 andMakarchenko et al. 2006). Parachironomus taishoabeus Sasa & Tanaka is a junior synonym of Saetheria tylus (Townes) (Kobayashi 2007). Parachironomus kuramaexpandus Sasa (examined by M. Spies) probably belongs to an undescribed genus near Rheomus, but definitely not to Parachironomus.
Based on examination of the holotype and paratype of Parachironomus lobus Yan, Saether, Jin & Wang by M. Spies, P. lobus is related to Demicryptochironomus (Irmakia) latior, but conclusive placement would require knowledge of the immature stages. The end of the superior volsella looks less expanded than in D. latior. For the moment we propose the new combination Demicryptochironomus (Irmakia) lobus and try to find at least the pupa of this species for further comparison with D. (I.) latior and other congeners.