A further study on littoral ciliates (Protozoa, Ciliophora) near King George Island, Antarctica, with description of a new genus and seven new species Author Wilbert, Norbert Author Song, Weibo text Journal of Natural History 2008 2008-04-30 42 13 - 14 979 1012 http://dx.doi.org/10.1080/00222930701877540 journal article 10.1080/00222930701877540 1464-5262 5219160 Pseudocohnilembus persalinus Evans and Thompson, 1964 ( Figures 3A , 8J–N ) Numerous cells were impregnated with both protargol and silver-nitrate methods. These isolates correspond perfectly to the redefinition by Song (2000) so that it is unnecessary to give a detailed redescription. Description Cell size about 30–40×20–25 Mm after silver impregnation; body shape as shown in Figure 3A , similar among individuals: anteriorly tapering, no distinct frontal plate. Area of buccal cavity wide, extending to about 1/2 of cell length. One large spherical macronucleus centrally located ( Figure 8K , arrowhead), micronucleus not observed. Buccal apparatus genus-typical ( Figure 3A ). Nine to 10 bipolar somatic kineties arranged sparsely, which are usually dikinetids in the anterior three-quarters of the body. About 20 basal bodies (or basal-body pairs) in each kinety. Silverline system as shown in Figures 3A , 8J, N , extrusomes not observed. Line along kinety No. n (first kinety to left of buccal field) continuing to caudal cilium complex, crossing through polar circle. Cytopyge (CyP) is thick argentophilic patch, located subcaudally ( Figures 3A ; 8M , arrow). Contractile vacuole pore (CVP) positioned invariably at end of 3rd somatic kinety ( Figures 8L , arrow, in M, arrowhead). Remarks This organism differs from the congener Pseudocohnilembus hargisi in body shape (oval versus slender), lower number of somatic kineties (9–10 versus 13–14) and the position of CV pore (consistently at the posterior end of third kinety versus posterior end between fourth and fifth kineties) ( Gong et al. 2002 ; Song and Wilbert 2002b ). Figure 2. Holosticha antarctica nov. spec. from life (A, E) and after protargol impregnation (B–D, F–H). (A) Ventral view of a typical specimen. (B, C) Ventral and dorsal views of the same specimen, to show the general infraciliature. (D) Detailed structure of buccal area, arrow marks the distal end of adoral zone. (E) To show different body shapes when crawling on a substrate surface. (F–H) Caudal part, to show the different appearance of the cirral patterns. Note that the transverse cirri are sometimes mixed with the marginal row. AZM, adoral zone of membranelles; BC, buccal cirrus; DK, dorsal kineties; EM, endoral membrane; FC, frontal cirri; FTC, frontoterminal cirri; LMR, left marginal row; Ma, macronucleus; Mi, micronucleus; MVR, midventral rows; PM, paroral membrane; RMR, right marginal row; TC, transverse cirri. Scale bars: 150 Mm (A, E); 100 Mm (B, D). Figure 3. Pseudocohnilembus persalinus (A), Euplotes vannus (B, C), Metaurostylopsis marina (D, E) and Holosticha apodiademata nov. spec. (F, G) after silver-nitrate (A) and protargol impregnation (B–G). (A) Ventral view of silverline system, arrow marks the small membranelle 3. (B, C) Ventral and dorsal view of the same specimen, arrow in B indicates the paroral membrane. (D, E) Ventral and dorsal views of the same specimen, doublearrowheads mark the posterior end of the ventral row, which is continued by the short midventral rows, while the arrow indicates the buccal cirrus. (F, G) Ventral and dorsal view of the same specimen, arrow marks the big gap between the two parts of the adoral zone. AZM, adoral zone of membranelles; CC, caudal cilia (in A) or caudal cirri (in B); BC, buccal cirrus; Cs, cytostome; CVP, contractile vacuole pore; CyP, cytopyge; DK, dorsal kineties; FC, frontal cirri; FTC, frontoterminal cirri; FVC, frontoventral cirri; M1, M2, membranelles 1 and 2; Ma, macronucleus; MC, marginal cirri; MVR, midventral rows; PM, paroral membrane; SKn, last somatic kinety; TC, transverse cirri. Scale bars: 25 Mm (A); 40 Mm (B–E); 50 Mm (F, G). Pleuronema coronatum Kent , 1881 ( Figures 8G–I ) This species was also identified from protargol-impregnated specimens (with many individuals). All morphometric data correspond perfectly to the previous descriptions ( Dragesco 1968 ; Foissner et al. 1994 ; Song and Wilbert 2002a ). Hence only some extra points will be supplied here. Size rather variable, 60–90 Mm in length, yet body shape consistent as seen in silver-impregnated specimens. Thirty-four to 37 somatic kineties. Micronucleus always globular, similar in size, and centrally positioned. Oral apparatus typically as described previously ( Figures 8G, I ; see also Song and Wilbert 2002a ). Always four preoral kineties in the present sample ( Figure 8H , arrowheads). Order HETEROTRICHIDA Stein, 1859 Genus Bickella nov. gen. Diagnosis for new genus Benthic Folliculinidae with Folliculina -typical peristomial lobes and ciliary structure; without lorica, marine habitat. Type species Bickella antarctica nov. spec. Dedication We dedicate this new genus to Professor Dr. Hartmut Bick, who in the 1960s established the Ciliatology School of Bonn University, from which both present authors graduated, and who has greatly contributed to the ecology of ciliates. Comparison and remarks This new, monotypic genus differs from all other folliculinids in the absence of the lorica and the style of free-swimming behaviour. Although the type species (see below as well) was found in large abundance by the authors during the 2002–2004 surveys, we were not quite sure whether this organism really does not have the lorica. Subsequent examination of many samples confirmed that this organism is a true lorica-free form, and therefore should be considered an undescribed taxon. It is reasonable to believe as well that it could be closely-related to other lorica-possessing folliculinids; for instance, the genus Heterostentor is similar to the typical periphytic Stentor , which was also found in the Antarctic area by the present authors ( Song and Wilbert 2002a ). The phenomenon of being ‘‘lorica-free’’ might represent an adaptation to the food-shortage biotope in Antarctic waters, i.e. organisms must more actively search for food in such an area. Bickella antarctica nov. spec. ( Figures 4A–E ) This species was initially described by Wilbert and Song (2005) as a unknown morphotype ( Folliculina ? sp., see Wilbert and Song 2005 , Figure 6 ). We re-collected Figure 4. Bickella antarctica nov. spec. (A–E) from life (A) and after protargol impregnation. (C) Lateral view, arrow marks the macronucleus. (E) Apical view, arrow marks the paroral membrane, arrowheads indicate the end of adoral-zone of membranelles. (D) Details of membranelles and paroral membrane. (B) Somatic kineties, composed of dikinetids. Scale bars: 100 Mm (A); 50 Mm (C); 20 Mm (E). and re-checked this organism and, based on both isolates, we establish a new species here. Diagnosis Bickella in vivo about 250 Mm long; two prominent peristomial lobes of approximately equal size; adoral zone of membranelles containing about 850–1250 membranelles, ca. 50–110 somatic kineties in mid-body; single globular macronucleus about 30 Mm across. Type locality Benthos samples from rockpools on the sea coast near Bellinghausen Station (62 ° 139S, 58 ° 589W) and in the littoral zone of Potter Cove (62 ° 149S, 58 ° 40W 9), King George Island . Description Body overall (including peristomial lobes) about 150–400Mm long. Body shape and size rather consistent in all populations observed, cells not very sensitive to disturbance or contractile; two ear-shaped wings wide and prominent, generally transparent except in the border area, where membranelles are arranged. Cytoplasm colourless, usually dark grey due to numerous food granules, especially under lower magnification. Macronucleus globoid, about 30 Mm across with many large nucleoli; micronuclei not detected. Two forms of locomotion observed: swimming slowly in the water without features, or using the caudal end to attach at the bottom ( Wilbert and Song, 2005 ).