Copepoda

Copepoda

Cyclops cf. herberti Einsle, 1996. The specimens collected in this study were not different from the original description of C. herberti. However, we restricted ourselves by identification to cf. since only three females were found. This is the first record of the species in Xinjuang and China. The species has been described from temporary ponds close to Lake Constance, and it is distributed from Poland and the southern part of Germany (Einsle 1996b) to southern France and central Italy (Dussart & Defaye 2006).

Cyclops strenuus (Fischer, 1851). The species is common in China and has been reported in Xinjiang (Shen et al. 1979). C. strenuus is a circumboreal species widely distributed throughout Africa, Europe, Asia, North and South America. However, it is part of a species complex and needs to be re-described (Dussart & Defaye, 2006). A detailed description of the species has been provided by Dussart & Defaye (1985) and Reed & McInture (1995). The main morphological characteristics of the studied specimens are presented at Fig. 3.

Mesocyclops dissimilis Defaye & Kawabata, 1993. This is the first report from Xinjuang. The species is distributed in the East Asia from North Vietnam to Japan and from South Korea to Easternmost Siberia. Previous records in China were from the following regions: Yunnan, Heilongjiang, Jilin, Inner Mongolia, Gansu, Shanxi, and Guizhou (Dussart & Defaye 2006; Zhao et al. 2012;). A detailed description of the species has been provided by Defaye & Kawabata (1993).

Mesocyclops pehpeiensis Hu, 1943. The species is common in the Guizhou and Jiangsu provinces of China (Guo 2000) and has been reported from Xinjiang near Ulungur Lake by Yang et al. (2011). M. pehpeiensis is distributed in East Asia (Kazakhstan, Uzbekistan, China, Myanmar, India, South Korea, Malaysia, Vietnam, Japan and Sri Lanka (Lim & Fernando 1985; Dussart & Defaye 2006)). This species was introduced in North America and was recorded in USA, Mexico, and Cuba (Suárez-Morales et al. 2005; Díaz et al. 2006). A detailed description of the species has been provided by Guo (2000).

Thermocyclops crassus (Fischer, 1853). The species is common and widespread in any aquatic habitat of China except for the Qinghai-Tibet plateau (Guo 1999). The species was reported from Ulungur Lake in Xinjuang by Yang et al. (2011). T. crassus is a widely distributed Holarctic species found in Asia, Europe, Africa, and North America (Duchovnay et al. 1992; Guo 1999; Chaicharoen et al. 2011). A detailed description of the species has been provided by Dussart (1969, 1982).

Eucyclops roseus Ishida, 1997. This is the first record of the species in Xinjuang and China. This species was described from Japan and was later collected in Lake Victoria, Kenya (Ishida 1998) and Korea (Lee et al. 2005). Presently E. roseus is actively dispersed and recorded in Ukraine (Anufrieva et al. 2014; Anufrieva & Shadrin 2016) and Germany (Alekseev & Defaye 2011). A detailed description of the species has been provided by Ishida (1997).

Characteristics of Cladocera and Copepoda faunas from Xinjiang. There are 88 species of Cladocera and Copepoda recorded from water bodies of the Xinjiang region (Table 2).

The species richness of Cladocera in the area (55 species) is higher than that of Copepoda (33 species). This fact can be explained by more effective long-distance dispersal of cladocerans (Novichkova & Azovsky 2016). The families Chydoridae and Daphnidae are the most abundant cladoceran groups in the area and include 24 and 14 species, respectively. The copepod family Cyclopidae contains 25 listed species, more than half of which belong to the genera Cyclops, Thermocyclops, and Eucyclops.

The taxonomical position of Eucyclops species of serrulatus group, which are included in the list of Xinjiang fauna (Table 2), agree with the latest revisions (Alekseev et al. 2006; Alekseev & Defaye 2011). In the сopepod fauna of China (Shen et al. 1979), Eucyclops serrulatus serrulatus (Fischer, 1851) was listed for the Xinjiang region. However, we included only Eucyclops serrulatus sensu lato according to the revision of Alekseev et al. (2006). The closest to Xinjiang occurrence of Eucyclops serrulatus are the lakes of western Mongolia (Alekseev & Defaye 2011). The subspecies inhabiting Xinjiang has not been elucidated (Dr. Alekseev V.R. personal comments).

The local endemic species have not been found in the fauna of the Xinjiang region. However, there is an endemic subspecies Arctodiaptomus altissimus pectinatus Shen & Song, 1965 which is known from the Tianchi Lake on the Bogda-Shan Mountain Range (Shen & Song 1965). There are no endemic Cladocera in the region. The two local Chydoridae species described by Chiang (1964), Pleuroxus sinkiankensis Chiang, 1964 and Camptocercus serratunguis Chiang, 1964 were found to be synonyms of Pleuroxus laevis G.O. Sars, 1862 (Smirnov 1996) and Camptocercus rectirostris Schödler, 1862 respectively (Smirnov 1998).

Diaphanosoma macrophthalma Korovchinsky & Mirabdullaev, 1995 +

Diaphanosoma mongolianum Uéno, 1938 +

Anomopoda

Daphnia carinata King, 1853 + Species All waterbodies Ulungur Bosten Ho Lake

Lake Alona quadrangularis (O.F. Müller, 1785) +

Flavalona costata (G.O. Sars, 1862) +

Coronatella rectangula (G.O. Sars, 1862) +

Camptocercus rectirostris Schödler, 1862. +

Camptocercus uncinatus Smirnov, 1971 +

Chydorus ovalis Kurz, 1875 +

Chydorus sphaericus (O.F. Müller, 1785) +

Disparalona cf. hamata (Birge, 1909) +

Disparalona rostrata (Koch, 1841) +

Dunchevedia crassa King, 1853 +

Ephemeroporus barroisi (Richard, 1894) +

Graptoleberis testudinaria (Fisher, 1851) +

Leydigia leydigi (Schödler, 1863) +

Monospilus dispar G.O. Sars, 1862 +

Pleuroxus aduncus (Jurine, 1820) +

Pleuroxus laevis G.O. Sars, 1862 +

Pleuroxus striatus Schödler, 1863 +

Pleuroxus truncatus (O.F. Müller, 1785) +

Pseudochydorus sp. +

Copepoda

Calanoida

Arctodiaptomus altissimus pectinatus Shen & Song, 1965 +

Arctodiaptomus rectispinosus rectispinosus (Kikuchi, 1940) +

Arctodiaptomus salinus (Daday, 1885) + + + Sinocalanus doerrii (Brehm, 1909) +

Cyclopoida

Cryptocyclops bicolor (G.O. Sars, 1863) + + Cyclops cf. herberti Einsle, 1996 +

Cyclops ladakanus Kiefer, 1936 +

Cyclops strenuus (Fischer, 1851) +

Cyclops vicinus vicinus Uljanin, 1875 + + Diacyclops bicuspidatus (Claus, 1857) + + Eucyclops macruroides (Lilljeborg, 1901) + + Eucyclops macrurus (G.O. Sars, 1863) +

Eucyclops roseus Ishida, 1997 +

Eucyclops serrulatus (Fischer, 1851) s. lat. +

Megacyclops viridis (Jurine, 1820) + + Mesocyclops dissimilis Defaye & Kawabata, 1993 +

Mesocyclops leuckarti (Claus, 1857) + + Mesocyclops pehpeiensis Hu, 1943 + + Metacyclops minutus (Claus, 1863) + +

......continued on the next page All species first discovered in the Xinjiang region were found in the underexplored and difficult to reach highland or deserted regions. For example, Mesocyclops dissimilis Defaye & Kawabata, 1993, Eucyclops roseus Ishida, 1997, Diaphanosoma macrophthalma Korovchinsky & Mirabdullaev, 1995 and Scapholeberis kingi G.O. Sars, 1903 were observed in the brackish oxbows of the Tarim River in salt marsh areas. The latter species also inhabits the oxbow of the Konchedarya River. Cyclops cf. herberti Einsle, 1996 was found only in the Tianchi Lake at an altitude of 2000 m.a.s.l. Simocephalus mixtus G.O. Sars, 1903 lives in small water bodies of the Bogda-Shan Mountain Range at an altitude of 3000 m.a.s.l. This species was found in the floodplain area of the Tarim River.

The finding of E. roseus in China is not unexpected because the species is widespread in East Asia (Lee et al. 2005). The discovery of C. cf. herberti in the Bogda-Shan Mountain Range significantly expands the range of the species. We have analysed the drawings of Cyclops sp., which is found in the Nilgiri Mountains (Tamil Nadu, India) (Einsle 1992), and assume that these individuals also most likely belong to the species C. herberti. Thus, this species rather has a wide range from boreal to tropical latitudes.

Approximately 40% of recorded Cladocera and Copepoda species from the Xinjiang region are found in the large Bosten and Ulungur lakes (Table 2), where hydrobiological studies are regularly conducted. Our findings further underline the uneven exploration of water bodies in this region and particularly of the small lakes and oxbows located in the mountain and desert areas.

The Cladocera fauna in the Xinjiang region is composed predominantly by common Palearctic species with wide ranges of distribution (82% of the total number of species). The East Asian subtropical species (7%) include Diaphanosoma dubium Manuilova, 1964, D. macrophthalma Korovchinsky & Mirabdullaev, 1995, D. mongolianum Uéno, 1938, and Moina salina Daday, 1888. The tropical species (11%) of the area include Daphnia carinata King, 1853, Scapholeberis kingi G.O. Sars, 1903, Ephemeroporus barroisi (Richard, 1894), Disparalona cf. hamata (Birge, 1909), Dunhvedia cf. crassa King, 1853, and Pseudochydorus sp. recorded by Chiang (1964) as P. globosus (Baird 1843). The Pseudochydorus sp. have a maximum female size of 0.53 mm, which is characteristic of the tropical species P. bopingi Sinev, Garibian & Gu, 2016. The maximum length of P. globosus s. str. is 0.8 mm (Sinev et al. 2016).

Copepods are mainly represented by cosmopolitan species with Holarctic ranges (41% of the total number of species). The two groups of species with broad Palearctic and East Asian ranges are second in species richness (24% and 20%, respectively). Tropical elements are comparatively rare in the fauna (15%) and include five species that are prevalent in Southeast Asia: Mesocyclops dissimilis Defaye & Kawabata, 1993; M. pehpeiensis Hu, 1943; Metacyclops pectinatus Shen & Tai, 1964; Microcyclops longiramus Shen & Sung, 1965; and Thermocyclops taihokuensis Harada, 1931.

A harsh continental climate with strong termic seasonality is common in the Xinjiang region. However, a large portion of the region is occupied by saline deserts (Cii 2001). These environmental conditions obviously impact the composition of planktonic crustaceans inhabiting the water bodies. The fauna of Copepoda and Cladocera includes primarily species with wide distribution covering Eurasia, Africa, and North America. The majority of these species are cosmopolitans and inhabit a wide range of habitats in various climatic zones. Colonization of tropical species (that inhabit the areas with wet and relatively mild climate with slight seasonal variability) to this region is difficult. Thus, the climatic characteristics and scarce wetland extensions in the Xinjiang region appears to be a barrier for the expansion of tropical Copepoda and Cladocera towards the north and possibly for the East Siberian species towards the south.