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New species of the diatom genus Fryxelliella (Bacillariophyta), Fryxelliella pacifica sp. nov., from the tropical Mexican Pacific
Author(s) -
HernándezBecerril David U.,
BarónCampis Sofía A.
Publication year - 2008
Publication title -
phycological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.438
H-Index - 44
eISSN - 1440-1835
pISSN - 1322-0829
DOI - 10.1111/j.1440-1835.2008.00496.x
Subject(s) - biology , simple eye in invertebrates , genus , taxonomy (biology) , diatom , type species , botany , zoology
SUMMARY During phytoplankton monitoring of coasts off Salina Cruz, Oaxaca, in the tropical Mexican Pacific, a new species, Fryxelliella pacifica sp. nov., was found and is described in this paper. The species is solitary, with cells of medium size, discoid with three relatively large ocelli on the valve face, located close to the margins (3–5 areolae from the margins) and placed symmetrically. Significantly, it possesses the morphological characters that distinguish the genus Fryxelliella from related genera: the presence of the ‘circumferential marginal tube’ (siphon marginalis), the external subcircular or subtriangular apertures at the valve margins, and the ‘juxtaposed rectangular plates’ in the valve mantle. The species that appears to be the most closely related is Fryxelliella floridana Prasad, an extant species and the type of the genus. However Fryxelliella pacifica differs from it (i) the size and shape of the cell; (ii) the size, location and structure of the ocelli (which additionally are not elevated); (iii) the shape and density of the subcircular to subtriangular marginal apertures; (iv) the external morphology of the rimoportulae (short process, two concentric tubes with the outer tube tip as a crown); and (v) it is marine rather than brackish. Externally the rimoportulae have a rather complex structure of two concentric tubes: the exterior tube has a tip divided like a crown. In spite of the fact this species was found in plankton samples, it is considered to inhabit sandy sediments (epipsammic) or as tychoplanktonic.