Anigsteinia clarissima, (ANIGSTEIN, 1912) ISQUITH, 1968

Yan, Ying, Fan, Yangbo, Chen, Xiangrui, Li, Lifang, Warren, Alan, Al-Farraj, Saleh A. & Song, Weibo, 2016, Taxonomy and phylogeny of three heterotrich ciliates (Protozoa, Ciliophora), with description of a new Blepharisma species, Zoological Journal of the Linnean Society 177 (2), pp. 320-334 : 329

COMMENTS ON ANIGSTEINIA CLARISSIMA ( ANIGSTEIN, 1912) ISQUITH, 1968

Anigsteinia clarissima , which is commonly found in intertidal regions of sandy beaches, was originally reported as Blepharisma clarissimum ( Anigstein, 1912) , but was reassigned by Isquith (1968) who established the genus Anigsteinia with A. clarissima as the type species. During the past century, numerous ‘populations’ of this taxon have been reported worldwide with rather conspicuous variations in morphology, from highly slender to elongated oval body shape, from widely rounded to pointed caudal end, and from 15 to over 30 macronuclear nodules ( Anigstein, 1912, see our Fig. 5B ; Kahl, 1928, Fig. 5H ; Kahl, 1932, Fig. 5D–F ; Yagiu, 1943, Fig. 5A ; Bock, 1952, Fig. 5I ; Dragesco, 1960, Fig. 5C ; Raikov, 1960, Fig. 5J ; Agamaliev, 1968, Fig. 5K, L ; Czapik & Jordan, 1976, Fig. 5M, N ; Dragesco & Dragesco-Kernéis, 1986, Fig. 5Q ). As most descriptions lack details of the ciliature or morphology in vivo, and because molecular data are lacking for almost all, evaluating these isolates remains a huge challenge. The Qingdao population corresponds extremely closely with the original description, the only difference being that the former has fewer macronuclear nodules (14–26 vs. 32–47). As this feature is population-dependent in most ciliates with multiple macronuclear nodules, we believe that the Qingdao isolate is a population of A. clarissima .

According to Isquith & Repak (1974), who provid- ed a taxonomic revision of Anigsteinia as well as a key to the species, and Dragesco (2002), who supplied the most recent review of A. clarissima , the original form described by Anigstein (1912) and the populations reported later by Kahl (1932) are clearly conspecific ( Fig. 5B, E, F, H ). Another isolate described by Kahl (1932), B. clarissimum forma arenicola Kahl, 1932 ( Fig. 5D ), is defined only by its body shape and ratio of body length to width. We believe that such differences are very likely to be population-dependent and hence this form to be conspecific with A. clarissima .

The form reported by Dragesco (2002) that was collected from Aber Bay, Roscoff ( Fig. 5O ) might belong to another species, Anigsteinia candida ( Yagiu & Shigenaka, 1956) Isquith & Repak, 1974 , because it has a very high number of macronuclear nodules (62 on average in Roscoff population; 181–287 in a Japanese population of A. candida described by Yagiu & Shigenaka, 1956; 200–260 in a Saudi Arabian population described by Al-Rasheid, 2000). Furthermore, Dragesco (2002) noted that the nodules ‘are not interconnected but freely disposed throughout the cell, especially in the central region’, which is also characteristic of A. candida ( Yagiu & Shigenaka, 1956; Al-Rasheid, 2000).

Since the review by Kahl (1932), over ten ‘populations’ have been reported under the names of B. clarissimum , B. clarissima , A. clarissimum , or A. clarissima ( Yagiu, 1943; Fauré-Fremiet, 1950; Bock, 1952; Dragesco, 1960, 1966; Raikov, 1960; Agamaliev, 1968; Fenchel, 1969; Hartwig, 1973; Czapik & Jordan, 1976; Hartwig & Parker, 1977; Dragesco & Dragesco-Kernéis, 1986; Fig. 5A, C, G, I, J–M, O–Q ). Amongst these, the identity of one of the isolates reported by Czapik & Jordan (1976) is questionable because it has an evidently wider body shape than is usual for A. clarissima ( Fig. 5M ). By contrast, another individual described by the same authors ( Czapik & Jordan, 1976) is probably correctly assigned because, as is typical for A. clarissima , it has a slender body with a pointed caudal region ( Fig. 5N ). Based on the diagrams supplied by Czapik & Jordan (1976), both of these isolates have significantly fewer adoral membranelles than is normal for A. clarissima ( Fig. 5M, N ). These drawings, however, were based on observations in vivo and so probably do not accurately represent the true number of membranelles present. Data based on silver-stained specimens are not available for either isolate.

Dragesco (1966) reported an organism from Thononles-Bains, France, that he called Blepharisma clarissimum , which has an obvious neck area and only about ten macronuclear nodules ( Fig. 5P ). Thus, it clearly differs from A. clarissima , which has no neck and about 15–45 macronuclear nodules. Isquith & Repak (1974) established a new species for this isolate, Anigsteinia oligonucleata ( Dragesco, 1966) Isquith & Repak, 1974 . The number of macronuclear nodules is not, however, a reliable character for species separation amongst ciliates with multiple macronuclear nodules ( Berger, 2008). Consequently the validity of A. oligonucleata awaits further support. The organism reported as A. clarissima by Ricci, Santangelo & Luporini (1982) has only nine macronuclear nodules and therefore is probably a population of A. oligonucleata if this is a valid species ( Fig. 5G ; Table 2).

Figures

Figure 5. Different isolates under the names of Anigsteinia clarissima (A–N, Q), Anigsteinia candida (O), and Anigsteinia oligonucleata (P). A, from Yagiu (1943). B, from Anigstein (1912). C, from Dragesco (1960). D, reported as Blepharisma clarissimum forma arenicola by Kahl (1932). E, from Kahl (1932). F, from Kahl (1932), after Anigstein (1912). G, from Ricci et al. (1982). H, from Kahl (1928). I, from Bock (1952). J, from Raikov (1960). K, L, from Agamaliev (1968). M, N, from Czapik & Jordan (1976). O, A. candida, reported as A. clarissima (misidentification) by Dragesco (2002). P, A. oligonucleata, reported as A. clarissima (misidentification) by Dragesco (1966). Q, from Dragesco & Dragesco-Kernéis (1986). Abbreviation: Ma, macronuclear nodules. Scale bars = 375 μm (O), 200 μm (E, I, M, N), 180 μm (H), 150 μm (D, G, J), 110 μm (F, Q), 80 μm (B), 60 μm (C, K, L, P), 40 μm (A).