Pa. Broady et M. Ingerfeld, 3 NEW SPECIES AND A NEW RECORD OF CHAETOPHORACEAN (CHLOROPHYTA) ALGAEFROM TERRESTRIAL HABITATS IN ANTARCTICA, European journal of phycology, 28(1), 1993, pp. 25-31
Descriptions are provided of cultured isolates of four species of chlo
rophyte microalgae which would traditionally be assigned to the Chaeto
phoraceae, Leptosiroideae (sensu Bourrelly, 1990). Light microscope ob
servations are supplemented by electron microscopy, particularly of py
renoid features. Three new species are described: Coccobotrys mucosus
sp. nov., Dilabifilum prostratum sp. nov. and Desmococcus endolithicus
sp. nov. Desmococcus olivaceus is a new record for Antarctica. Diagno
stic features of the new species include extensive gelatinisation of c
ell walls in old cultures of C. mucosus, growth of a well-developed ps
eudoparenchymatous prostrate system in liquid cultures of D. prostratu
m, and production of quadriflagellate zoospores by D. endolithicus whi
ch is a new observation for this genus. Unusual and contrasting ultras
tructural features of the pyrenoid are described for D. prostratum and
the Desmococcus species. The former is traversed by appressed pairs o
f thylakoids coated with pyrenoglobuli; the latter is traversed by sin
gle thylakoids with pyrenoglobuli surrounding the pyrenoid matrix.