Those pesky Caribbean damselfish! They have been confusing even the most experienced REEF surveyors for years! After consulting with the leading damselfish taxonomist experts, Paul Humann and Ned DeLoach revised the descriptions and updated pictures for four species - Cocoa Damselfish (Stegastes variabilis), Beaugregory (Stegastes leucostictus), Longfin Damselfish (Stegastes diencaeus), and Dusky Damselfish (Stegastes adustus). One of the most noticeable changes from what many of us learned - Cocoa Damselfish don't always have a spot at the base of the tale and Beaugregory often have a spot!
A recent discussion thread on the REEF ID Central Discussion Board highlights the confusion around damselfish. Take a look at the thread (http://www.reef.org/node/3853) and see what you think!
The revised pages, meant to replace pages 124-129 in the 3rd edition of Reef Fish Identification, are available for download as PDFs below, courtesy of New World Publications. The text and pictures were reviewed by Dr. Ross Robertson with the Smithsonian's Tropical Research Institute in Panama, who is considered the world's authority on Western Tropical Atlantic damselfishes, and Dr. Mark Steele at University of California, Santa Barbara, another damselfish taxonomist.
Long-time REEF Advanced Assessment Team member, Neil Ericsson, has also compiled the key features into a handy matrix. The matrix is available as a PDF here. All of these resources are also linked from the Damselfish Revised page on the REEF website -- www.REEF.org/damselfish.
Revised Damselfish Descriptions and Pictures (PDFs)
Cocoa Damselfish (Stegastes variabilis)
Beaugregory (Stegastes leucostictus)
Longfin Damselfish (Stegastes diencaeus)
Dusky Damselfish (Stegastes adustus)