M. Goldmorgan et al., FRESH-WATER EPIPHYTIC CYANOPROKARYOTES FROM CENTRAL MEXICO .2. HETEROGENEITY OF THE GENUS XENOCOCCUS, Archiv fur Protistenkunde, 144(4), 1994, pp. 383-405
Second article of the series of studies about the cyanoprokaryotic (cy
anophycean, cyanobacterial) species, growing epiphytically on submerse
d filamentous algae in central Mexico. The traditional genus Xenococcu
s was found to be heterogeneous and the stability and frequency of int
er- and intrageneric characters was studied in natural populations fro
m central Mexican streaming waters, sampled in the period from 1983 to
1993. The types of cellular binary fission and nanocytic cell divisio
n were particularly studied, and from them were derived different life
-cycle strategies. The genus Xenotholos gen.n. was separated from the
genus Xenococcus on the basis of these results, and seven species were
studied from both genera (one new species of Xenococcus and three new
species of Xenotholos were described). Characteristics of all species
studied are included. Another group of traditional Xenococcus-species
, which does not correspond morphologically either to Xenococcus or to
Xenotholos, and cells of which never divide by multiple fission, must
be also separated from the genus Xenococcus (X. minimus type).