In 1964 and 1965, Shen & Tai described two species of calanoids, which they classified in the South American genus Argyrodiaptomus. We examined new material from the terra typica, South China, and show that both species belong in the Asian genus Sinodiaptomus. A biogeographic anomaly is thus corrected. Moreover, the two appear to be sister species and males are morphologically well separable. No intermediate morphotypes have so far been detected. S. cavernicolax (Shen & Tai, 1965), known only from the type locality, was claimed to be cavernicolous, but shows no stygobitic adaptations, and has eyes. It may have been pushed back into the cave environment by its congener S. ferus (Shen & Tai, 1964) with which it coexists in the same lake system.
So far, four species of Sinodiaptomus have been found in China: the two mentioned above, i.e., S. cavernicolax only in Longyan Cave of Zhaoqing City, and S. ferus at about five locations, but its range is limited to a small part of Guangdong Province. All five other species of Sinodiaptomus, among which the other two that occur (also) in China, also occupy small to very small ranges, with the type species (S. chaffanjoni Richard, 1897) only living in North China, and S. indicus Kiefer, 1936 and S. mahanandiensis Reddy & Radhakrishna, 1980 confined to South India (Reddy & Radhakrishna, 1980). S. valkanovi Kiefer, 1938 from Japan is invasive (Ueda & Ohtsuka, 1998; Makino et al., 2010). S. sarsi Rylov, 1923, distributed in Japan, China, and most of Mongolia, is separated by a wide disjunction from a group of populations in Iran, the Caucasus, and East Anatolia. This western group of populations might be a separate species and deserves more study.
Structural controls and hydrogeochemical properties of geothermal fields in the Varto Region, East Anatolia
