European Journal of Protistology 48 (2012) 63–72 Morphology and infraciliature of two new marine ciliates, Paracyrtophoron tropicum nov. gen., nov. spec. and Aegyria rostellum nov. spec. (Ciliophora, Cyrtophorida), isolated from tropical waters in southern China Xiangrui Chen a,b , Xiaozhong Hu b,∗ , Jun Gong c , Khaled A.S. Al-Rasheid d , Saleh A. Al-Farraj d , Weibo Song b a College of Life Science and Biotechnology, Ningbo University, Ningbo 315211, China b Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China c Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China d Zoology Department, King Saud University, Riyadh 11451, Saudi Arabia Received 11 October 2010; received in revised form 20 July 2011; accepted 21 July 2011 Available online 17 September 2011 Abstract The morphology and infraciliature of two new marine cyrtophorid ciliates, Paracyrtophoron tropicum nov. gen., nov. spec. and Aegyria rostellum nov. spec., isolated from tropical waters in southern China, were investigated using live observation and protargol impregnation methods. Paracyrtophoron nov. gen. differs from the closely related Cyrtophoron by lack of fragment kinety at anterior ends of right somatic kineties and thigmotactic cilia in posterior portion of ventral surface, while from the well-defined Chlamydodon by lack of the cross-striped band around the periphery of the somatic field. Paracyrtophoron tropicum nov. spec., the type of the new genus, can be recognized by the combination of the following characters: cell size about 150–175 × 70–90 m in vivo; elliptical to kidney-shaped in outline, dorsoventrally flattened about 2.5:1; conspicuous cortical granules; one canal-like depression extending from postoral area to subcaudal region of cell; ca. 90 somatic kineties; 12–16 nematodesmal rods; one or two terminal fragments on dorsal side. Aegyria rostellum is characterized by the following features: size about 90–150 × 40–70 m in vivo, triangular or ear-shaped body with broad anterior end, having a rostriform structure and pigment spots, 56–63 somatic kineties, one preoral kinety, three or four circumoral kineties, and 32–42 nematodesmal rods. Based on previous and current studies, the definition for the genus Aegyria is updated: body dorsoventrally flattened; oral ciliature consisting of one preoral and several circumoral kineties; podite located in posterior ventral region and surrounded by somatic kineties; no obvious gap between right and left somatic kineties; postoral and left somatic kineties progressively shortened posteriorly from right to left. Additionally, two new combinations were proposed. © 2011 Elsevier GmbH. All rights reserved. Keywords: Aegyria; Marine ciliates; Morphology; New species; Paracyrtophoron ∗ Corresponding author. E-mail address: xiaozhonghu@ouc.edu.cn (X. Hu). 0932-4739/$ – see front matter © 2011 Elsevier GmbH. All rights reserved. doi:10.1016/j.ejop.2011.07.005