Comparative morphology of the Candoninae antennula, with remarks on the ancestral State in ostracods and a proposed new terminology (Crustacea, Ostracoda) Ivana Karanovic Karanovic, I. (2005): Comparative morphology of the Candoninae antennula, with remarks on the ancestral State in ostracods and a proposed new terminology (Crustacea, Ostracoda). -Spixiana 28/2: 141-160 The antennula in Ostracoda is usually considered uniramous. However, because of the clear presence of an exopod in Darwinulidae, it is supposed that this ramus existed once in the ostracod ancestor, and such antennula is presented in this paper. The remnants of the exopod, as well as protopodal and endopodal segments are recognized in some ostracod orders, especially Podocopida. In addition, the anten-nula of the Candoninae ancestor is proposed in the present paper, with a new setal terminology which is simpler and more appropriate to identify the position of setae on Segments and appendages in general. The Candoninae ancestor's antennula consists of one segmented protopod, which comprises the fused coxa and basis; two setae of the exopod; and the six-segmented endopod, with a knee connection between the first and the second segments. Description, variability and a compara-tive analysis of the antennula in the 26 living genera of the subfamily Candoninae are given. The articulation is confirmed to have an important generic value, with the plesiomorphic six-segmented endopod found in 13 genera. Fusion of the en-dopodal segments which is mostly found between the second and third, and the fourth and fifth segments, is found in ten genera. The remaining three Candoninae genera have different fusions all of which are autapomorphies. Compared with the ancestor's antennula, the living representatives have reduced setae on the poste-rior side of segments and on the proximal, rather than the distal, end of the append-age. The most primitive setal pattern is found in the genus Cryptocandona Kauf-mann, 1900, while the most derived one is found in the genera Terrestricandona Danielopol & Betsch, 1980 and Deminutiocandona Karanovic, 2003. Although the setal pattern tends to be constant within a genus, considerable Variation occurs, and so the setation should be treated with caution on the generic level. Ivana Karanovic, Western Australian Museum, Francis Street, Perth WA 6000, Australia. Introduction Crustacea is a very ancient arthropod group with the fossil record dating back to the early Cambrian (McKenzie 1983, Martin & Davis 2001, Maas et al. 2003). What undoubtedly indicates its monophyly is the naupHus larva bearing three pairs of functional appendages: antennula^ antennae and mandibule (McKenzie 1983, Boxshall 1997). In all Crustacean groups several body appendages have changed from the primitive biramous crustacean plan (containing three segmented protopod, two rami, endites and epipodites -see Forest 1994, Cohen et al. 1998; etc.) to highly specialized appendages. In recent crustaceans different appendages serve different functions (sen-sory, feeding, locomotion, copulation), show a 141
BioStor
