Atlantid Heteropods as Living Substrata for Eggs of Halobates sericeus (Heteroptera: Gerridae)

Atlantid heteropods are collected occasionally in Hawaiian waters with yellow, narrowly elliptical objects attached to their shells. Examination of 139 of these objects from 72 atlantids showed that they consisted of an outer, clear capsule whose contents were usually yellow, although 16 were empty and four contained brown insects at an advanced stage of development. The latter were identified as preemergent nymphs of the Pacific pelagic seaskater or ocean strider, Halobates sericeus Eschscholtz. The maximal number of attached capsules was four, although most shells (79%) had one or two. Capsules averaged 0.93 mm long and 0.36 mm wide and were deposited on either the right, left, or both sides of the shell. All 72 atlantids with egg capsules were adult males. Exclusive usage of males by H sericeus is suggested to result from swarming behavior by male atlantids at the water surface. Although egg capsules were recorded from eight species of atlantids, most (86%) were on Atlanta turriculata d'Orbigny and A. fusca Souleyet, two of the most strongly pigmented species. Hypothetically, these two species would be the most visually conspicuous to H sericeus at the ocean surface

Structure, distribution, and seasonal dynamics of the benthic community in the upper Newport Bay, California

The benthic community in the Upper Newport Bay was sampled at two intertidal and two subtidal depths at three stations during five assessment periods between October 1977 and January 1979. Heavy sediment deposition occurred during the 1977-1978 winter period, and the sedimentary environment was transformed from one characterized by fine sands (January 1978) to one dominated by silts (January 1979). Total density, species richness, and species diversity were generally lowest at the uppermost station (Ski Zone) and highest at the lowermost station (Shellmaker Island). Immediately following the 1977-1978 winter rainy period, total faunal density was extremely low, particularly at the Ski Zone station. However, heavy recruitment after April 1978 resulted in maximal total density values at all stations in August 1978. Species richness was highest during October 1977 and lowest in April 1978 following the heavy rainfall period. The benthic community was dominated in October 1977 by three polychaetes, Fabricia limnicola, Streblospio benedicti, and Capitella capitata. By August 1978, F. limnicola had not recruited back into the community and three additiona1 polychaete species (Polydora ligni, Pseudopolydora paucibranchiata, and Scolelepis acuta) shared community dominance with C. capitata and S. benedicti. The crustaceans showed strong seasonal oscillations, being abundant in the October and August samples and occurring sparsely in the January and April samples. (76pp.

A review of the ecology, palaeontology and distribution of atlantid heteropods (Caenogastropoda: Pterotracheoidea: Atlantidae)

Fewer than 1% of marine gastropod species live a holoplanktic life. Of these, the shelled heteropods of the family Atlantidae are among the most poorly understood. The atlantids potentially make up an important part of the ocean zooplankton, composing up to 69% of shelled holoplanktic gastropods in the Late Pleistocene to Recent fossil record. They are also likely to be at high risk from current and future global changes, including anthropogenic ocean acidification. However, due to their small size (<12 mm), difficulty of sampling and complicated morphology, we still lack key information about atlantid taxonomy and ecology. This makes it difficult to understand how important they are in the ocean foodweb and how they will be affected by environmental change. Although many studies have been carried out on the atlantids, these have generally been broad and unconnected. Here, we draw together this previous research, summarizing what is currently known about atlantid taxonomy, palaeontology, ecology and biogeography, and aiming to provide a foundation for future research on this group. The data indicate complex behaviours involving seasonal and vertical migration, and demonstrate extended geographical ranges, with implications for understanding the role of atlantids in the ocean foodweb and their sensitivity to environmental changes. This review highlights the urgent need for further taxonomic research on the atlantids, including molecular analysis, and for improved sampling techniques