Masahiro Dojiri

A NEW SPECIES OF COPEPODA (THAUMATOPSYLLIDAE) SYMBIOTIC WITH A BRITTLE STAR FROM CALIFORNIA, U.S.A., AND DESIGNATION OF A NEW ORDER THAUMATOPSYLLOIDA

Abstract A new species of thaumatopsyllid copepod, Caribeopsyllus amphiodiae, is described based on adult specimens reared from nauplii inhabiting the stomach of a burrowing, amphiurid brittle star, Amphiodia urtica (Lütken), collected in California, U.S.A. It is the first member of the family to be reported from the eastern Pacific Ocean. Caribeopsyllus chawayi, its only known congener, inhabits the Caribbean Sea. All other thaumatopsyllid species occur in the eastern hemisphere. Caribeopsyllus amphiodiae is only the second thaumatopsyllid of which both sexes and sexual dimorphism have been described and for which a host species has been identified. Caribeopsyllus differs from confamilial genera by the presence of a 1-segmented leg 4 exopod. The new species is distinguished from C. chawayi by its general habitus, and by the absence of spiniform processes at the base of each exopodal spine of leg 1 and the first three exopodal spines of leg 2. Analysis of the phylogenetic relationships of Thaumatopsyllidae shows that it is not a member of any of the other previously established orders of Copepoda. Accordingly, a new order, Thaumatopsylloida, is proposed to accommodate the five species of thaumatopsyllids thus far reported and is shown to be a member of a Thaumatopsylloida-Monstrilloida-Siphonostomatoida clade.

Arrama, new genus (Siphonostomatoida : Caligidae), with two new species, copepods parasitic on Australian fishes

ABSTRACT A new genus, Arrama, and two new species, A. tandani and A, cordata, belonging to the copepod family Caligidae (Siphonostomatoida), are described from the gill filaments of two species of plotosid catfishes, Cnidoglanis macrocephalus (Valenciennes) and an undescribed species of Paraplotosus, respectively, from Australia. The new genus can be distinguished from confamilial genera by a combination of characters that include (1) the reduced apical armature of the leg 1 exopod, (2) the 2-segmented rami of leg 2, (3) the absence of the ventral apron of leg 3, and (4) the reduction of legs 3 and 4 to setiferous lobes. The two new species are distinguished from each other by the shape of the genital complex, the setae of the caudal ramus, the arrangement of spinules of the canna of the second maxilla, the apical armature of the leg 1 exopod, and the terminal armature of the leg 2 exopod. The morphology of the suckerlike cephalothorax of the members of the Caligidae appears to be an adaptation for attachment to smooth flat surfaces, i.e., external body surfaces, buccal cavity walls, and branchial chamber walls of the hosts. Two genera, Abasia and Hermilius, have become specialized for living on gill filaments of their hosts by modifications of their cephalothoraces. Although the ventral apron, a structure formed by the expansion of the intercoxal plate and sympod of leg 3, remains intact in these two genera, it may no longer be functional. Members of the new genus, Arrama, which also live on gill filaments, lack the ventral apron.