For the purpose of taxonomical description of marine oligotrich ciliates, water samples were collected from the southern coast of Korea (Masan Bay and Jangmok Bay). Ciliate cells were identified based on protargol impregnated specimens. As a result, four oligotrich ciliates were identified and redescribed:
Ciliates have been recognized as important components in the marine microbial food webs and oligotrich ciliates usually occurred dominantly among the planktonic ciliate community(Froneman and Perissinotto, 1996; Quevedo and Anadon,2000). According to Lynn (2008), the oligotrichs were divided into two subclasses; the Oligotrichia (oligotrichs sensu stricto) and the Choreotrichia, while the halteriids were affiliated with the stichotrichs. To date, about 1,490 species of oligotrichs (sensu lato) have been described worldwide but the validity is not confirmed. Of them, about 120 oligotrichids and 80 aloricate choreotrichids (not including tintinnids) have been recorded, only about 60% have been described, or redescribed using protargol staining method (Agatha, 2004a,2004b, 2011; Agatha and Struder-Kypke, 2007). Studies on marine planktonic ciliates have been carried out in Korea since 1980’s, only 4 oligotrichids and 10 aloricate choreotrichids have been reported (Table 1) (Suzuki and Han, 2000;Jeong et al., 2004; Moon et al., 2004; Kim et al., 2005, 2008,2010b; Ma and Choi, 2005; Lee et al., 2006).
The ecological roles of Korean oligotrichs (especially, loricate tintinnids) have been investigated in many studies (Yoo and Park, 2001; Kim and Lee, 2003; Yang and Choi, 2003;Moon et al., 2004; Kim et al., 2007; Lee et al., 2007; Han and Lee, 2010; Lee and Kim, 2010). They are frequently collected and abundant in the surface layer of coastal water and easily identified due to their large size and conserved lorica (Yoo et al., 1988; Yoo and Kim, 1990). Aloricate oligotrichs are more abundant than loricate tintinnids in microzooplankton community (Vaque et al., 1997; Ota and Taniguchi, 2003).However, most ecological studies do not include them because they are not easy to handle due to their limited taxonomic information, fragility and small size of body (Yoo and Park,2001; Kim and Lee, 2003; Lee and Kim, 2010). The taxonomic information of these taxa in Korea is urgently needed to investigate other related studies. Therefore we describe here four aloricate oligotrichs with their abundance including water temperature and salinity.
Ciliate samples were seasonally collected from Masan Bay
using Van Dorn sampler at 0.5 m depth of selected sampling sites (32 sites) from April 2006 to November 2008 (February,May, August, and November). In Jangmok Bay, ciliates were sampled by vertical towing from 5m depth to surface using a 20 ㎛ mesh plankton net (30 cm diameter) in June 2009(Fig.1 ). Samples were fixed immediately by Bouin’s solution (at final concentration 10%, v/v) in which most of the ciliates were well preserved. Water temperature and salinity were measured
In order to observe the morphological characteristics of ciliate cells, the fixed cells were stained and mounted using the quantitative protargol staining and the modified Wilbert’s method (Wilbert, 1975; Montagnes and Lynn, 1987; Foissner et al., 1999). Ciliate cells were identified and counted under ×400-1,000 magnification using a light microscope (Zeiss Axioskop II, Goettingen, Germany).
Terminology and classification for the ciliate taxonomy are according to Montagnes and Lynn (1991) and Agatha (2004a).
Korean name: 1*폐구환소모충목, 2*폐구환무각소모충아목, 3*이종렬소모충과, 4*단이종렬소모충속, 5*원추단이종렬소모충
Class Oligotrichea Butschli, 1889
Subclass Oligotrichia Butschli, 1889
1*Order Choreotrichida Small and Lynn, 1985
2*Suborder Strobilidiina Jankowski, 1980
3*Family Strobilidiidae Kahl in Doflein and Reichenow,1929
4*Genus Rimostrombidium Jankowski, 1978
5*Rimostrombidium conicum (Kahl, 1932)
(Table 2,Fig.2 )
Strobilidium conicum Kahl, 1932: 506.
[Fig. 2.] Rimostrombidium conicum after protargol impregnation. A Ventral view; B Dorsal view; C F Oral primordium (OP) originating between SK2 and SK3 (arrow indicating OP in C); D Left view; E Black arrowhead indicating a conspicuous AP; G White arrow indicating Mi; H I Apical view showing EPks IPk and black circle (double arrowhead showing IPk in H and I black arrow indicating black circle in H); J-M SK arrangement. AP apical protuberance. Scale bar: 10 μm.
Rimostrombidium conicum Petz and Foissner, 1992: 160;
Agatha and Riedel-Lorje, 1998: 14.
than the other kineties, and spirally extending to posterior cell end, SK1, 3, 4, 5, and 6 not extending to posterior end and slightly curved or straight; one Ma C- or horseshoe-shaped and horizontally located underneath EPZ.
EPZ closed and surrounding anterior end of cell, consisting of 22-26 polykinetids (average 24, n=23). Two elongated EPks extending into eccentric oral cavity. One IPk lying into oral cavity and separated from EPks. A black circle observed below anterior part of EPZ, having gap into oral cavity (“C”shaped position), probably fibres (Fig.2 H, I).
Six SKs composed of short cilia. Except for SK2, SKs not extending to posterior pole of cell and having similar lengths:SK1, 12 μm; SK3, 10 μm; SK4, 12 μm; SK5, 12 μm; and SK6, 11 μm on average. SK2 longer than the other kineties(average 22 μm in length, n=8), slightly sinistrally spiraled and extended to posterior pole of cell. SK1 and SK6 less or not sinistrally curved than SK3-5 slightly dextrally curved or longitudinal (Fig.2 J-M).
Single Ma C- or horseshoe-shaped and contained numerous globular nucleoli, horizontally located underneath EPZ with ventrally opening. One ellipsoidal Mi positioned on dorsal side of Ma (Fig.2 G).
1*Order Oligotrichida Butschli, 1889
2*Family Strombidiidae Faure-Fremiet, 1970
3*Genus Omegastrombidium Agatha, 2004
4*Omegastrombidium kahli Song et al., 2009
(Table 2,Fig.4 )
Omegastrombidium kahli Song et al., 2009: 336-337.
[Fig. 4.] Omegastrombidium kahli after protargol impregnation. A E F Ventral view (double arrowhead in F indicating pTM); B GDorsal view; C H Left view (white arrows in H indicating direction of GK); D Right view. DC distended cell surface. Scale bar: 10 μm.
Oral polykinetids surrounding anterior pole with ventral opening, divided into AM and VM. Approximate 44-58 AM(average 52, n=7) and 6-13 VM (average 9, n=7). Two pTM positioned between AM and VM and obviously longer than AM and VM (Fig.4 A, F).
GK originated at anterior part of body, both ends facing on left side of anterior part and turning approximately 1.5-2 whorls (with dextrally spiraling) and then terminating at pos-
About 35-62 (average 45, n=8) ellipsoidal Ma (2-5.5 μm in diameter), scattered throughout cell.
in morphology: marine species collected from coastal water in salinity about 30 psu; cell shape; the number of AM and VM; the presence and number of pTM, and the shape and number of Ma. However, cell size of Korean population is smaller than Chinese population (43-82×28-45 μm of Korean population vs. 60-80×40-50 μm of Chinese population).Number of Ma of Korean population is larger than that of Chinese population (35-62 vs. 20-30). Chinese population is vague about the appearance of an AP but Korean population shows a conspicuous protrusion at anterior end of the cell after protargol impregnation.
1*Family Tontoniidae Agatha, 2004
2*Genus Spirotontonia Agatha, 2004
3*Spirotontonia turbinata (Song and Bradbury, 1998)
(Table 2,Fig.6 )
Spirotontonia turbinata Song et al., 2009: 334.
Buccal cavity open on ventral side, extending slightly to right and terminating approximately 1/2 of way down cell.AM and VM positioned like question-marked (“?”) on ventral side. About 13-15 AM (average 14, n=8). VM extended along left side of buccal cavity and consisting of 15-20 membranelles(average 17, n=9). A row of EM lying on inner wall of buccal lip on right inner side of oral cavity, consisting of densely arranged monokinetids (Fig.6 A, C).
Sinistrally spiral GK orientating on left side of buccal cavity,extending to left lateral side along posterior margin of VK then spirally turning down to posterior of body with about 2 whorls (average of GK per 10 μm, 12). “L” shaped fibres located above GK and arranged along GK (average of F per 10 μm, 9). No VK detected.
Ellipsoidal Ma scattered in whole of body, size 3-3.5 μm in diameter (average 3 μm in diameter, n=3), 50-60 in number(average 55, n=3).
4*Spirotontonia grandis (Suzuki and Han, 2000)
(Table 2,Fig.8 )
Tontonia grandis Suzuki and Han, 2000: 989-994.
Spirotontonia grandis Agatha, 2004a: 298.
Buccal cavity open, extending obliquely to right and terminating about 1/2 of way down cell. AM surrounding AC region, consisting of 13 to 15 AM (average 14, n=22). VM extending along left side of buccal cavity, consisting of 23-34 membranelles (average 28, n=23). A row of EM lying on
[Fig. 8.] Spirotontonia grandis after protargol impregnation. A C Ventral view; B Dorsal view; D Left view (B and D show that tailis located on the second whorl GK); E Detail of GK arrangement with F (probably fibers); F Detail of tail appearance top is the frontview and bottom is the back view with wrinkled surface; G Plated-form on surface of DC. AC apical collar; F probably fibers; DCdistended cell surface. Scale bar: 10 μm.
inner wall of buccal lip on right side of buccal cavity, consisting of monokinetids.
Sinistrally spiral GK, with a total of three whorls, located below posterior part of buccal cavity, extending to left lateral side along posterior margin of VK and turning around dorsal side horizontally, then sharply going down to proximal part on ventral side and then spirally going down two whorls,finally terminating at posterior end of dorsal side. F (probably fibers) parallel arrangement above GK; “L”-shaped in
stained (the number of kinetids per 10 μm GK=15 and F=7 on average). No VK detected.
Oval or irregular shaped Ma scattered in whole of body,3-4 μm in diameter (average 3 μm, n=19), and 37-84 in number(average 65, n=19).
Korean name: 1*개구환소모충목, 2*민소모충과, 3*오메가열소모충속, 4*다핵오메가열소모충 Korean name: 1*꼬리소모충과, 2*나선체꼬리소모충속, 3*원추나선체꼬리소모충, 4*큰나선체꼬리소모충