New web-based identification guides for aquatic organisms
Science Centres: Aquatic Biodiversity and Biosecurity
A series of web-based guides designed to help identify marine and freshwater organisms is one of the latest initiatives by NIWA’s Centre for Aquatic Biodiversity & Biosecurity. The guides, produced through the FRST-funded programme Biodiversity of New Zealand Aquatic Environments, are now available on the NIWA website and include the following:
Guides to New Zealand freshwater crustaceans
NIWA has produced quick-guides for several groups of common freshwater crustaceans, including Amphipoda, planktonic Copepoda, and planktonic Cladocera (water-fleas). The guides are designed for rapid identification, usually to genus level, and can be easily accessed at www.niwa.co.nz/ncabb/tools/quickguides.
Caddisfly larvae – genus Psilochorema (Hydrobiosidae)
Psilochorema (Hydrobiosidae).
An interactive guide on an aquatic insect group, the common caddisfly, has been produced after the successful introduction of a quick-guide to New Zealand chironomid midge larvae (Diptera). We know of 15 species of the common caddisfly (Trichoptera) genus Psilochorema (Hydrobiosidae), which makes it the third most diverse hydrobiosid genus from New Zealand. While most Psilochorema larvae are easily distinguished from other hydrobiosid genera, species identification is often difficult because differences between species are generally small, descriptions may be ambiguous and applicable to more than one species, or the larvae have not been described. A web-based guide to the mature larvae of Psilochorema has been developed using Lucid – an innovative and interactive identification programme.
Lucid enables the user to match a list of characters and relevant colour photographs that most closely resemble the features of their specimen. Each time a relevant image is selected, all those that do not match the selected choices are rejected. This process eliminates a large number of redundant characters, images, and species, and continues until only one species or a shortlist of species remains. Species descriptions, distribution maps, habitat information, and a suite of colour photographs (some with simple animations) can be viewed at any time throughout the identification process. The programme can also suggest the best character to choose for quick identification.
This fully interactive guide lets the user identify the larvae of 12 Psilochorema species, including the descriptions of 7 previously unknown species. Images, distribution data and maps, and descriptions of Psilochorema species will be regularly updated.
A guide to the mature larvae of Psilochorema can be viewed at www.niwa.co.nz/rc/prog/freshbiodiversity/psilochorema.
Families of planktonic calanoid Copepoda (Crustacea)
Different screenshots of the Copepoda key.
This group of small crustaceans mainly inhabits the upper layers of the open sea. Calanoid copepods are a vital link in the food web because they are found in such large numbers throughout the world’s marine and fresh waters. Many commercial and non-commercial marine fish (and some crustaceans) are completely dependent on copepods as a source of food for part of their larval life. For example, in New Zealand the larvae of hoki, which form the basis of our largest fishery, feed almost exclusively on copepod adults (e.g., Calocalanus) and juveniles. The faeces of copepods are also an important source of food for detritus feeders at the sea floor.
You can access the user-friendly key to the families of calanoid Copepoda by going to www.niwa.co.nz/rc/biodiv/ and clicking on the link “keys to the families of calanoid Copepoda”. At the bottom of the introductory page, click on the darkened key symbol opposite “Calanoida families”, and then go to the second sentence that shows you how to download and install the key for free.
Guide to the common genera of freshwater diatoms in New Zealand
You can now use NIWA’s website to help identify the common genera of freshwater diatoms – single-celled algae with silica cell walls. The key has been designed to help non-specialists better understand the diatom taxa in periphyton samples (benthic algal growth) from rivers and streams. Diatoms are a major component of periphyton, and changes to their community composition can indicate changes in instream habitat and water quality. The key introduces 41 diatom genera (mostly benthic but a few planktonic). Each character is illustrated, and many of the characters are visible in your live material at low power (e.g., x400). There is an explanation for each genus, including general information about habitat and ecological preferences. The key uses the Lucid programme and can be downloaded at www.niwa.co.nz/rc/prog/freshbiodiversity/diatom.