Pseudouroleptus jejuensis, Jung & Park & Min, 2014

Jung, Jae Ho, Park, Kyung Min & Min, Gi Sik, 2014, Morphology and Molecular Phylogeny of Pseudouroleptus jejuensis nov. spec., a New Soil Ciliate (Ciliophora, Spirotrichea) from South Korea, Acta Protozoologica 53 (2), pp. 195-206 : 201-206

Comparison of P. jejuensis with similar species:

Pseudouroleptus caudatus is the sole species in the genus and consists of 2 subspecies (for review of the genus Pseudouroleptus , see Berger 2008): Pseudouroleptus caudatus caudatus Hemberger, 1985 and P. caudatus namibiensis Foissner, Agatha and Berger, 2002 . Pseudouroleptus jejuensis differs from these subspecies mainly by the number of dorsal kineties, which include an additional dorsal kinety in comparison with the other 2 subspecies. The detailed comparison is discussed below.

Pseudouroleptus caudatus caudatus is the nominotypical subspecies and differs from P. jejuensis mainly by the dorsal kineties (4 vs. 5). However, the dorsal kineties are not clearly recognizable from previous reports ( Hemberger 1982, Foissner et al. 2002). Thus, to establish a new species in Pseudouroleptus further investigation on the type species is necessary. Fortunately, Küppers and Claps (2013) reported the morphology of a Argentine population with a clear illustration of the dorsal kineties. The Argentine population has a consistent morphology with the type population and these two populations are located in the same continent, South America, so that conspecificity is beyond reasonable doubt. Based on a comparison with these populations of P. caudatus caudatus , we confirm that the Korean population is a new species in Pseudouroleptus . Pseudouroleptus caudatus caudatus can be separated from P. jejuensis by dorsal kineties (4 vs. 5), and development of caudal cirri from dorsal kinety 3 anlage (present vs. absent). Additionally, the former species forms a single caudal cirrus in dorsal kinety 1 (vs. 3–5 in P. jejuensis ) ( Hemberger 1982, Berger 1999, Küppers and Claps 2013, Küppers pers. comm.).

Pseudouroleptus caudatus namibiensis can be distinguished from P. jejuensis by having fewer adoral membranelles (33–51 vs. 52–62), right frontoventral cirri (20–31 vs. 46–58), dorsal kineties (4 vs. 5), and caudal cirri (1–4 vs. 4–7). In P. caudatus namibiensis , the right frontoventral row is distinctly shorter than in P. jejuensis ; this difference in length results in the different number of cirri.

In the ontogenesis, the processes are almost identical in P. caudatus caudatus and P. jejuensis with the exception of these characteristics: i) the number of caudal cirri developed from dorsal kineties 1, 3 anlagen; and ii) the number of dorsal kineties developed from dorsal kinety 3 anlage. Although Hemberger (1982) described these numbers of P. caudatus caudatus in the text, clear illustrations are not available to support the description in his paper. Recently, Küppers and Claps (2013) reported the morphology of the Argentine population of P. caudatus caudatus . According to Küppers and Claps (2013) and a personal communication to Küppers, the Argentine population differs from the Korean population by 4 dorsal kineties (vs. 5), 1 caudal cirrus at the end of dorsal kinety 1 ( Küppers and Claps 2013, p. 70, Fig. 4C ; vs. 3–5 caudal cirri), 1 caudal cirrus at the end of rightmost dorsal kinety ( Küppers and Claps 2013, p. 70, Fig. 4C ; vs. caudal cirri lacking), and number of dorsal bristles in each row ( Küppers and Claps 2013, p. 70, Fig. 4C ; DK1: 23 vs. 29–44; DK2: 23 vs. 29– 40; DK3: 21 vs. 25–40; rightmost DK: 21 vs. 24–37). These comparisons confirm the Korean population is new species.

Our gene trees support the assignment of this new species as a distinct species in Pseudouroleptus , with full supporting values ( Fig. 4 ). With the exception of Stylonychinae, other nodes presented low supporting values. Additional SSU rRNA gene sequences of representative oxytrichids are required to clarify these relationships, and these sequences should be combined with morphological data even for well-known species.

Acknowledgements. This study was supported by the program on Management of Marine Organisms causing Ecological Disturbance and Harmful Effects funded by KIMST/MOF, the National Institute of Biological Resources (NIBR) of the Korean Ministry of Environment, as parts of the Discovery of Korean Indigenous Species Project 2013 and Graduate Program for the Undiscovered Taxa of Korea (1834-302), and the Inha University.

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Received on 4 th April, 2013; revised on 1 st August, 2013; accepted on 23 rd August, 2013

Figures

Figs 4A–D. Pseudouroleptus jejuensis, middle (A, B) and late divider (C, D) after protargol impregnation. Note that the parental dorsal bristles are shown by single dots although still composed of dikinetids. The parental dorsal dikinetids become smaller and are less impregnated than newly developed one. A, B – dorsal (A) and ventral (B) views of middle divider showing dorsal kineties and cirral anlagen. C, D – dorsal (C) and ventral (D) views of late divider showing dorsal kinety 3 fragmentation (double arrowheads). Note that caudal cirri are developed at posterior end of kineties 1, 2 only (arrows). Postperistomial cirrus (arrowheads) is originated from the anlage IV and split from anterior part of the anlage. IV–VI – cirral anlagen IV–VI. Scale bars: 150 μm.