Taxonomic studies on Aegyria apoliva sp. nov. and Trithigmostoma cucullulus (Müller, 1786) Jankowski, 1967 (Ciliophora, Cyrtophoria) with phylogenetic analyses (2023)


The cyrtophorian ciliates, which have been found worldwide, are a highly specialized and divergent group (Agamaliev, 1983, Baldock et al., 1983, Borror, 1972, Carey, 1992, Deroux, 1970, Dragesco, 1966). To date, more than 160 morpho-species have been reported, although information regarding the ciliary pattern is only available for less than half of them. The series of researches conducted by Deroux, 1970, Deroux, 1974, Deroux, 1976a, Deroux, 1976b, Deroux, 1976c, which revealed the ciliary patterns of most cyrtophorian genera, are usually regarded as a milestone in taxonomic studies of cyrtophorians. Subsequently, numerous studies concerning this group have been published (e.g., Blatterer and Foissner, 1992, Chen et al., 2011, Foissner, 1988, Foissner et al., 1991, Gong et al., 2002, Gong et al., 2005a, Shao et al., 2008, Song, 2003). However, most of these works lack molecular data and some even lack detailed live observations (Warren et al. 2017). Therefore, redescriptions are still important for this group.

Trithigmostoma Jankowski, 1967 was established based on the characteristic of its continuous ventral kineties, which differs from the ciliary patterns of other chilodonellids (Jankowski 1967). Its validity was further supported by recent molecular phylogenetic investigations (Chen et al., 2016, Gao et al., 2012, Wang et al., 2017). Although Trithigmostoma is common in freshwater, only two species are contained in GenBank database, and most species are yet to be redescribed. The history of Aegyria Claparède and Lachmann, 1859 is much more complicated with two synonyms, namely, Genotrochilia Diesing, 1866 and Aegyriana Deroux, 1975 (Chen et al. 2012). Both its morphological and molecular characters strongly support its assignment to the family Hartmannulidae Poche, 1913. Following recent investigations, several new members have been assigned to this group, and such studies have indicated that the body shape and size, the number of somatic kineties, the number of nematodesmal rods, and the number of transpodial segments are all reliable characters for species separation (Chen et al., 2012, Qu et al., 2017).

During the last decade, a series of investigations concerning ciliated protozoa have been carried out in the coastal waters of China, and over 40 new or previously poorly known cyrtophorid ciliates have been reported (Chen et al., 2012, Fan et al., 2014, Gong and Song, 2006a, Gong and Song, 2006b, Gong et al., 2007, Gong et al., 2008, Liu et al., 2017, Pan et al., 2012, Pan et al., 2013a, Pan et al., 2013b, Pan et al., 2016, Pan et al., 2017, Qu et al., 2015a, Qu et al., 2015b, Qu et al., 2017). These studies have revealed that the diversity of marine cyrtophorians has been underestimated, especially in the undersampled habitats, e.g. subtropical coastal waters and mangrove wetlands.

As a new contribution, we collected two cyrtophorians. After morphological and molecular studies were performed using state-of-the-art methods (Warren et al. 2017), we found that one represented a new member of the genus Aegyria, named Aegyria apoliva sp. nov., while the other was an estuarine population of Trithigmostoma cucullulus (Müller 1786) Jankowski, 1967, whose morphology was already well investigated, but SSU rDNA is revealed here for the first time.

Section snippets

Material and Methods

Sample collection, observation and identification (Fig. 1a–c). Aegyria apoliva sp. nov. was isolated from glass slides, which were immersed in coastal water off Qingdao (salinity 28.5‰ and water temperature about 20 °C) for 9 day to form biofilms (Gong et al. 2005b) (Fig. 1a, b) on June 26, 2008. The Guangzhou population of Trithigmostoma cucullulus was sampled from the Pearl River estuary (salinity 4.3‰ and water temperature about 27 °C) (Fig. 1a, c) on November 9, 2008.

The isolated cells were

Results and Discussion

Order Dysteriida Deroux, 1976

Family Hartmannulidae Poche, 1913
Genus Aegyria
Claparède and Lachmann, 1859
Aegyria apoliva sp. nov.(Table 1;Figs. 2a–c, 3a–j)
Marine Aegyria 100–120 × 50–70 μm in vivo; body shape generally broadly oval with a protrusion and dark pigment spot on anterior left body portion; 48–69 somatic kineties; one preoral and four or five circumoral kineties; 9–13 transpodial segments; 26–40 nematodesmal rods; 6–10 contractile vacuoles; single juxtaposed heteromerous


This work was supported by the National Natural Science Foundation of China (Projects number: 31401954, 31772431) and China Postdoctoral Science Foundation (Project numbers: 2014M550378 and 2015T80753). Many thanks are due to Prof. Weibo Song, Ocean University of China, for his helpful suggestions on preparing the manuscript. We are grateful to Prof. Shan Gao, Ocean University of China for her help on DNA sequencing. Furthermore, we greatly appreciate the help of two anonymous reviewers and the

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