Macrorhynchia species (Cnidaria: Hydrozoa) from the Bunaken Marine Park (North Sulawesi, Indonesia) with a description of two new species

摘要

Five species of Macrorhynchia from the Bunaken National Marine Park (North Sulawesi, Indonesia) are described. Three species, M. philippina, M. spectabilis and M. phoenicea were already known for the Indo-Pacific area, M. asymmetrica and M. fulva aredescribed as new species. Macrorhynchia asymmetrica n. sp. is easily distinguished from the other species of the genus due to the hypertrophic lateral nematotheca that is bent downwards. Macrorhynchia fulva n. sp. is distinguishable from its congeners especially through the lateral nematothecae pointing in opposite directions, the large marginal tooth, and the presence of the well-marked adcauline teeth. The shape and the colour of living colonies are described, thereby allowing the recognition of the species directly in situ. Generally, the observed specils live on the deeper portions of the reef, but M. spectabilis occurs at more shallow depths. Almost all the recorded specie! have an annual cycle characterised by higher abundances during the wet season while they are absent or rare during the dry period. Only M. asymmetrica has the opposite pattern, being more abundant during the dry months.