Abstract:Since marine medusae and ctenophores harbor a wide variety of symbionts, from protists to fish, they constitute a unique community in pelagic ecosystems. Their symbiotic relationships broadly range from simple, facultative phoresy through parasitisim to complex mutualism, although it is sometimes difficult to define these associations strictly. Phoresy and/or commensalism are found in symbionts such as pycnogonids, decapod larvae and fish juveniles. Parasitism and/or parasitoidism are common in the following symbionts: dinoflagellates, ciliates, anthozoan larvae, pedunculate barnacles, anuropid isopods, and hyperiid amphipods. Mutualism is established between ctenophores and gymnamoebae, and between rhizostome medusae and endosymbiotic dinoflagellates. More information on symbiotic apostome ciliates, anthozoan larvae and hyperiid amphipods is definitely needed for further studies in consideration of their high prevalence and serious damage they can inflict on their hosts. The present paper briefly reviews previously published data on symbionts on these gelatinous predators and introduces new information in the form of our unpublished data.

We describe a new species of Crambionella, C. helmbiru, from central Java, Indonesia. The combination of the mean number of lappets per octant (14), presence of foliaceous appendages amongst frills on oral-arms, absence of tubercles on the velar lappets, proportion of terminal club length to oral-arm length (0.28), and the body colour distinguish this species from three previously described congeners. In addition, the analysis of partial sequences of the cytochrome c oxidase subunit I gene indicate substantial genetic differences from both Crambionella orsini and Crambionella stuhlmanni, supporting the validity of this new species. A combination of morphological and genetic approaches determined that the remarkable differences in exumbrellar colours observed in specimens are simply intra-specific variation. Surprisingly, this species has been commercially harvested for more than 20 years and is well-known to the local people in the region, yet it had remained unknown to science until this point. The commercial fisheries targeting this formerly unknown species are also described in detail.

<strong>Mangrove Gastropods from Lombok Island, West Nusa Tenggara.</strong> Mangrove forest in Lombok island covers an area of 3,305 ha; an area of 1,643 ha (49.7%) is still in good condition and the remaining 1,662 ha (50.3%) is in damaged condition. The damaged mangrove will impact on the decline of fauna biodiversity. This research was conducted in April 2015 and aimed to determine the composition and distribution of mangrove mollusks, especially gastropods, in Lombok Island. The method used is purposive sampling and visual encounter. Observations were carried out at six stations. A total of 1,236 specimens have been collected, consisting of 11 families and 31 species. Species composition ranged 5–13 species for each station. Gastropod species composition was influenced by physical environmental conditions of mangrove forest. Chicoreus capucinus was the only carnivorous gastropod found in this location and Haminoea tenera (Haminoeidae) was a new record for Indonesia. <br /><br />

Banyak situ di daerah Bogor dan sekitarnya terus menyusut oleh pendangkalan maupun alih fungsi lahan yang akan berpengaruh pada keanekaragaman spesies fauna akuatik, termasuk keong air tawar. Penelitian mengenai keanekaragaman dan ditribusi keong air tawar penghuni situ dilakukan di Kabupaten Bogor (Situ Cilalay, Situ Ciriung, Situ Kabantenan) dan di Sukabumi (Situ Gunung) pada bulan September-November 2017. Penelitian ini mengidentifikasi spesies keong air tawar, menganalisis persamaan komposisi spesies dan distribusinya, serta menganalisis faktor lingkungan yang memengaruhinya. Pengambilan sampel keong di masing-masing situ dilakukan di tiga stasiun menggunakan petak berukuran 5 x 1 m 2 . Sebanyak 936 individu spesimen dari 12 stasiun telah dikoleksi dan diidentifikasi, terdiri dari 7 famili dan 12 spesies keong air tawar. Filopaludina javanica mendominasi populasi di Situ Cilalay, Situ Ciriung, dan Situ Kabantenan dengan kehadiran 417 individu (44,5%), sementara Melanoides tuberculata merupakan spesies dengan distribusi paling luas yang ditemukan di 11 dari 12 stasiun. Dua spesies, Clea sp. yang ditemukan di Situ Cilalay dan Polypylis kennardi yang ditemukan di Situ Ciriung dan Situ Kabantenan belum pernah dilaporkan penelitian terdahulu.

National Park plays important role in maintaining natural ecosystems such as freshwater ecosystems. Meru Betiri National Park is loacted in southern East Java, it covers two regencies, Banyuwangi and Jember. A recent survey was carried out in two resorts, Bandealit and Andongrejo, to study the diversity of freshwater gastropoda. We had collected 86 specimens which consisted of five families, seven genera, and nine species. Seven species were found from Andongrejo and four species were found from Bandealit. River in the Bandealit primary forest area had the highest diversity with four species. The relations between diversity and environmental conditions will be discussed briefly in this paper.