Morphological Species Identification

pml zooplanktonIt is widely accepted that the study of biodiversity should be documented as rigorously as possible through carefully planned biological collections, which should be managed as a valuable resource for use by the entire world scientific community, present and future. Taxonomy and systematics are the scientific basis to address biodiversity, traditionally relying on external morphological description, a complex process that requires a detailed characterization and later identification of specimens by experts, demanding a high level of expertise. The morphological taxonomist work is difficult and time-consuming, requiring years of experience, and many times has considerable restrictions such as the phenotypic plasticity and the genetic variability in the populations, or the detection of morphologically cryptic taxa, being helpful only for a particular life stage or gender. These limitations to biodiversity assessment constituted the driving forces for emerging approaches to species identification.

Molecular studies always require a solid knowledge on the morphology of adults and larval stages of target species. The morphological identification of the specimens is made with the aid of microscopes (electron, stereo and optical), according to previous descriptions of the studied species. Experts of the different zooplankton groups are essential to validate the identifications and construct morphological data matrixes, and/or keys, for selected species, with morphological characters considered taxonomically informative, enabling its use in the phylogenetic analysis of plankton distributed around the world. The organization of reference collections from which several images of identified specimens of species of living zooplankton will be prepared to be used as tools for taxonomic identification (e.g. fragile gelatinous forms). Whenever possible, according to international standards certifying compatibility, reproducibility, and knowledge extension in all areas of biological research, the tissue samples of conveniently identified specimens or the entire specimens, conveniently identified (voucher specimens), will be the core material for molecular taxonomy.