Didemnidae (Tunicata: Ascidiacea) dos French Frigate Shoals

Abstract

Ascidians are a diverse class of benthic marine invertebrates, and about 20% of the described species belong to the family Didemnidae. This is due especially to the high diversity of the genus Didemnum, with over 200 known species. Although widely distributed, little is known about this fauna from many regions of the world, such as the Hawaiian archipelago. French Frigate Shoals (Kanemilohai) is the first and the largest atoll located North of the Hawaii mountain chain and belongs to Papahãhanaumokuãkea Marine National Monument, which is the largest US conservation area and one of the largest protected areas in the world. In 2006 an expedition was conducted to French Frigate Shoals as part of the Census of Marine Life program, in order to assess the diversity of cryptic organisms. The ascidians were collected at 18 stations through SCUBA diving or snorkelling. The specimens were collected manually on the reef or from the breakdown of dead coral blocks brought on board. Later they were sent to the Laboratório de Ecologia Animal, Instituto de Ciências do Mar - UFC, where are preserved in 70% ethanol solution. A total of 127 specimens of sea squirts from the Didemnidae family were collected. Of these species, only D. cf. candidum, D. granulatum, D. perlucidum, D. listerianum, D. simile and L. rufus were previously registered to Hawaii, so this work is also the first record of 19 more species to the Hawaiian Archipelago. This work is the main contribution to ascidians of Hawaii.