Abstract 43
1 Consulting Engineering Office for Ecology, Radetzkystr. 10, 5020 Salzburg, Austria 2 Laboratory of Protozoology, Ocean University of China, Qingdao 266003, China 3 Department of Biology, University of Ulsan, Ulsan 680-749, Korea 4 Zoology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia * E-mail corresponding author: office@protozoology.com (Helmut Berger) Abstract The morphology, the infraciliature, some ontogenetic stages, and the SSU rRNA gene sequence of the little-known marine 18-cirri hypotrich Tachysoma rigescens (Kahl, 1932) Borror, 1972 [basionym Oxytricha (Tachysoma) rigescens], isolated from mariculture waters near Qingdao, China, were investigated. The species is characterised, inter alia, by narrowly spaced, small, colourless cortical granules and several ring-shaped structures in the cytoplasm. The caudal cirri and the simple dorsal kinety pattern (3 bipolar kineties) obviously taken over from the ground pattern of the Hypotricha, the composition of the adoral zone of the proter from new and parental membranelles, as well as the presence of two 'extra' cirri behind the rear end of the right marginal row strongly suggest a misclassification in Tachysoma. The SSU rRNA gene sequence data indicate that T. rigescens branches off very early in the Hypotricha tree, which supports the hypothesis that the 18-cirri pattern occurred probably already in the last common ancestor of the Hypotricha. A detailed survey of the early branching 18-cirri hypotrichs and similar taxa reveals that for T. rigescens a new genus has to be established, Apogastrostyla nov. gen., because there are, inter alia, important differences in the dorsal infraciliature. Besides the type species, A. rigescens nov. comb., which seems to be confined to the northern hemisphere, a second marine species, A. szaboi nov. comb. (basionym Hemigastrostyla szaboi) can be included. Since no type material of A. rigescens is available and the type locality is not known the Chinese population is fixed as neotype. Funded by the Austrian Science Fund (FWF; Project P20569-B17; H. Berger), the Natural Science Foundation of China (project numbers: 30870264, 40906065); and the Center of Excellence in Biodiversity, King Saud University (111 Project [No. B08049]). This name is disclaimed for nomenclatural purposes (ICZN 1999, Article 8.3). Key words: cell division, infraciliature,
ontogenesis, phylogeny, Spirotricha, taxonomy
Keywords: Hypotricha, Hypotrichida, Stichotrichida, stichotrichs, Asia, bochemsitry, molecular biology, marine biology, Yellow Sea Dr Helmut BERGER Consulting Engineering Office for Ecology - Technisches Büro für Ökologie Radetzkystrasse 10, 5020 Salzburg, Austria, Europe Phone +43-(0)662-432538; Fax +43-(0)662-443139; email office@protozoology.com; http://www.protozoology.com |