Descriptions of the dorid nudibranchs Polycera hedgpethi Marcus, 1964 and P. Fujitai Baba, 1937 in New Zealand (Gastropoda: Opisthobranchia)

Abstract

New Zealand specimens of Polycera hedgpethi Marcus, 1964 and P. fujitai Baba, 1937 are described formally and in detail for the first time. Both species are easily recognised from previous descriptions. Five polycerid species are known now from New Zealand waters. The largest New Zealand specimen of P. hedgpethi collected so far is only two-thirds of the size of the type. This size difference may account for some of the differences noted, e.g., number of rows of radular teeth. New Zealand specimens differ from the original description in lacking yellow pigment on the notal ridge, tail crest and upper border of the foot, and in possessing a wider foot, a subterminal band of orange brown pigment on the extrabranchial processes, and opaque and crystalline white scattered on the body and appendages. Subsequent description shows close similarity except in two cases, in one the grey/black pigment is flecked not spotted, the jaws are rounded not angular and allosperm and vaginal ducts join before reaching the spermatheca, in the other the primary colour is dark brown, there is no white pigmentation and the jaws are rounded. Polycera hedgpethi is compared with three very similar species, P. hummi Abbott, 1952, P. aurisula Marcus, 1956 and P. gnupa Marcus & Marcus, 1967: It is distinguished from them by the dense grey/black spotting and lack of blue pigment on the notal appendages. Polycera gnupa is believed by some to be synonymous with P. hedgpethi. Here P. gnupa is maintained as a distinct species in having brown as the basic colour, cylindrical extrabranchial processes and unipinnate gills. The New Zealand specimens of Polycera fujitai agree well in colour and form with the original description except that they differ in basic colour in being dull orange not brown or yellowish brown. There are differences in colouring between the local and Hong Kong specimens, the former having grey and orange as the foundation of the pattern, a blue tinge to the rhinophores and the opaque yellow widespread.