Du. Hernandez-becerril et E. Bravo-sierra, Planktonic silicoflagellates (Dictyochophyceae) from the Mexican Pacific Ocean, BOTAN MARIN, 44(5), 2001, pp. 417-423
One hundred and sixty Formalin-preserved net samples were collected from di
fferent zones in the Mexican Pacific Ocean during 11 cruises and other surv
eys (1984-1999) to study the composition of silicoflagellates. A few bottle
samples from a coastal zone containing living material were also analyzed.
Observations were made by light and scanning electron microscopy., We desc
ribe five taxa of silicoflagellates: four species and one variety, includin
g some morphological variants (traditionally considered as recognized speci
es or varieties). Living specimens of Dictyocha californica were also studi
ed, from which we consider it to be an extant species. Dictyocha calida may
also be regarded as an extant species, as it is very characteristic and re
adily distinguished, with no intergrades with related taxa, but no living c
ells or cells with chloroplasts were found. A discussion of morphological v
ariation of some species within the group and the characters of the siliceo
us skeleton as taxonomic criteria are given. The most ubiquitous species wa
s Dictyocha fibula (and its related 'species' or varieties), found in most
of the locations sampled, whereas D. californica and D. fibula var. robusta
are regarded as neritic, warm water forms.