Distribution of Protonemura in the East Palaearctic and Oriental Region

(Fig. 5)

The greatest diversity of Protonemura is in the Mediterranean subregion, where nearly a hundred species are known from various but mainly crenal habitats (Graf et al. 2009). Only a few species are known from the East Palaearctic and even fewer species from the Oriental Region. Most of the eastern species inhabit the Pacific Islands and along the Pacific Coast. Twelve species are endemic to the four main Japanese islands, the southern Kurils and Sachalin; one of species occurs also on the Continent in the Primorie of Russian Far East (Shimizu 1998, Zhiltzova 2003). The Korean Peninsula has a further endemic species (Ham & Lee 1999, Murányi & Park 2011), an unnamed species was reported on the basis of a single female from Okinawa (Shimizu 1998) and we have described herein P. bifurcata, the first species from Taiwan. All these 15 species belong to four closely related species groups endemic to the Far East. The other nine species, are distributed in continental East Palaearctic and Oriental regions, but cannot be placed into Pacific species groups. The two species described by Wu (1949) from Fujian Province of southeastern China are species incertae sedis (Baumann 1975, Yang et al. 2015); if they are species of Protonemura, then both must be considered as isolated distributed species. The westernmost species is known from Arunachal Pradesh of India (Kimmins 1950, Aubert 1967), however, only the female is known and its generic identity is questionable (Murányi & Li 2013). The species P. filigera Kawai, 1969 was described from Thailand and would be the southernmost member of the family, however, also regarded as an incertae sedis (Baumann 1975). The original description of P. filigera notes only one pair of sausage-like cervical gills (Kawai 1969); we transfer herein this species to Indonemoura, I. filigera (Kawai, 1969) comb. n. The other four Oriental species (P. bidigitata Du & Wang, 2007 (in Du et al. 2007) from Yunnan Province of southwestern China; P. biintrans Li & Yang, 2008a from Guangdong Province of southeastern China; P. fansipanensis and P. neofiligera Sivec & Stark, 2009 from Lào Cai of northern Vietnam), along with P. macrodactyla Du & Wang, 2007 (in Du et al. 2007) from Palaearctic Central China (Gansu, Ningxia and Hubei: Du et al. 2007, Yang et al. 2015) are geographically isolated species with unknown phylogenetic affinities. However, the herein described P. datongensis from the Palaearctic Qinghai Province of the Qinghai-Tibetan Plateau of western China seems to be a true member of the corsicana species group sensu Vinçon & Murányi (2009). This species is the only eastern Protonemura belonging to a western group. The corsicana group is speciose and has the largest distribution among the defined species groups, including all of the Mediterranean, and dispersed into the East Palaearctic in northern Iran (Vinçon & Murányi 2009). The presence of a member of this group on the eastern edge of the Qinghai-Tibetan Plateau may indicate that the disjunction area of Protonemura was indeed connected through the Asian high mountains, and their absence from Central Asia and the western Himalayan ranges is due to relatively late geological or climatic events.