Okavango Delta Expedition

Field Guides and Keys

Roger Bills, head of the fishes team, shows Department of Fisheries employees how to identify fish using a field guide.

"Budzanani, can you tell me what species you have there?" asked Fred Ellery, plant team leader. "I think it's Thelypteris interrupta, but I'd like to check it," he responded. He pulls out a field guide, authored by Fred, to confirm the species of fern he's sampled.

Field scientists rely on keys and field guides to confirm the identity of species and to spell their names in Latin. This is the way most students learn about a species group. It's not enough to memorize a key because in the field, things can appear completely different than in a book.

The students on AquaRAP are fortunate to have a team of scientists with them that, combined, have more than 250 years of field experience. While their knowledge is practically encyclopedic, field guides are important back-ups. The team is carrying field guides on the plants, mollusks, mammals, and fish of the Okavango.

"Once you have a specimen, you can begin trying to identify it by asking questions," said Chris Appleton, invertebrates team leader.

Plant sampling.

For example, if I'm collecting snails and mollusks, the first difference I'd look for between them is whether their shells are spiraled or smooth, with two shells. The spiraled shells are types of snails and the others are mollusks," he said. "Then I'd continue asking questions: does it have an operculum (a covering over the opening of the shell)? From there you can go to the key and begin narrowing it down to an individual species."

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