Background.

Within any given taxocenosis of benthic diatoms (BDT), the distribution of the taxa relative abundances renders them as very abundant, common, uncommon, and rare taxa. This structure is considered when estimating species diversity using Shannon’s index (H’) based on information theory. Thus, because this distribution also occurs within the taxonomic hierarchy of BDT, i.e., genera with a high number of species-infraspecies (SS) or species singletons, estimating species diversity (H’) using the genus/SS ratio instead of relative abundances, represents an alternative measure of diversity but resorting to a much smaller data matrix. Hence, the diversity index designated H’G/SS is proposed here.

Objective.

In this essay, we sought to gather evidence that combining information on the genus-level taxa and their included SS provides a reliable estimation of taxonomic diversity for BDT. Hence, we tested the hypothesis that the estimated H’G/SS for the floristic of BDT in a particular locality would be as high as the highest value using diatom relative abundances.

Method.

To test the above, floristic and species diversity (H’) data from several studies of BDT along Mexican shores were analyzed quantitatively under the premise that diversity estimates based on relative abundances of species (H’) or the H’G/SS index would be equivalent.

Results.

Statistical tests supported our hypothesis showing no significant differences between the original values of H’ and those using H’G/SS.

Conclusions.

This diversity estimation using H’G/SS for BDT represents a reliable, quicker, and more comprehensive approach and another parameter that can be used for further conservationist, ecological, and biogeographical purposes.