Golden algae: A biology of Chrysophytes.

This little book is clearly a paean to chrysophytology. What it lacks in beautiful illustrations is more than compensated by a wealth of information about the past and present of this specialized field of study and the fascinating organisms being studied. Following a chapter in which the novice is given a peek into the sacred precincts, there are chapters on chrysophyte taxonomy, nutrition, evolution, biogeography and ecology. Electron microscopy and genomic analysis are powering the dynamics of the taxonomy and phylogeny of chrysophytes, which display great diversity. Kristiansen pays homage to his forebears, presenting portraits of 13 persons who have made significant contributions to the study of chrysophytes (O.F. Müller, Villars, Ehrenberg, J.B. Petersen, Pascher, Doflein, Bourrelly, Manton, Christensen, Fauré-Fremiet, Korshikov, Asmund and Nygaard). Silica-scaled chrysophytes are of particular interest in that they play an important role as indicator organisms in paleolimnology. Mallomonas in the Synurophyceae is the largest genus of silica-scaled chrysophytes. There are 325 entries for specific and infraspecific taxa of Mallomonas in the Index Nominum Algarum, from M. acaroides Zacharias to M. zellensis Fott, and the pool of possible new species seems far from empty. According to Kristiansen, 172 species have been described on the basis of EM examinations. ‘In many cases it has been possible to correlate species described from LM to species known from EM. But for almost a hundred taxa described from LM . it has been impossible to identify them with any known taxa’ (p. 83). It is disconcerting that Mallomonas acaroides Perty is maintained as the name of the generitype. Perty (‘Zur Kenntniss kleinster Lebensformen’, 1852) established the genus Mallomonas on the basis of a single species. On page 83 he mentioned Mallomonas acaroides var. epilis, but in his formal systematic treatment (p. 171) he published the new species as ‘[Mallomonas] Plösslii. * t.XIV, f. 19, A-C. (Früher M. acaroides.)’. The legend to plate XIV, figure 19, on page 215 reads ‘Mallomonas Plšsslii’, while the ‘Register’ on page 224 lists ‘[Mallomonas] acaroides’ as a synonym of ‘Mallomonas Ploesslii’. It is clear that Mallomonas acaroides and M. acaroides var. epilis are invalidly published names because they were not accepted by their author, who described the taxa under the validly published names M. ploesslii [‘Plösslii’] and M. ploesslii var. epilis, respectively. Considering that the name M. acaroides has been widely used to the exclusion of M. ploesslii and that 17 varieties have been described within M. acaroides, this specific name appears to be a good candidate for conservation. If conservation were to be proposed, however, its effect on M. acaroides Zacharias would have to be considered. Zacharias (Forschungsber. Biol. Stat. Plön 1: 17. 1893) did not explain why he chose to apply Perty’s invalidly published epithet to a different species, but he clearly distinguished his new species from M. ploesslii Perty. In an epilogue to Golden Algae, Kristiansen writes, ‘The book gives an overview of the state of the art in chrysophyte research, how our knowledge has expanded and what problems are in focus now. ’ The book does more than that, however. It reveals the heart and soul of someone who has devoted his professional life to studying these fascinating creatures.