Scheltema Rudolf S.

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Scheltema
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Rudolf S.
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  • Technical Report
    Development and planktonic larvae of common benthic invertebrates of the Woods Hole, Massachusetts region : summary of existing data and bibliographic sources
    (Woods Hole Oceanographic Institution, 1984-04) Scheltema, Rudolf S.
    The early life histories of more than one-half of the most common benthic invertebrates from the region of Woods Hole, Massachusetts have not been described. In many instances it has not even been determined whether or not the development of a species includes a planktonic stage. Larvae taken from the plankton often cannot be identified to species or even to genus because descriptions of their morphology do not exist; those descriptions that do exist are widely scattered in the biological literature. The extent of information that is available for the identification of larval forms is tabulated here for the most common species within the major benthic taxa in the Woods Hole region: gastropods, bivalve mollusks, decapod and stomatopod crustaceans, cirriped crustaceans, polychaete annelids, and echinoderms. (Not included are amphipods and isopods, and other peracarid crustacea, which do not have planktonic larval stages.)
  • Preprint
    Seasonal occurrence of balanomorph barnacle nauplius larvae in the region of the Antarctic Peninsula
    ( 2010-03-01) Scheltema, Rudolf S. ; Scheltema, Amelie H. ; Williams, Isabelle P. ; Halanych, Kenneth M.
    Plankton samples taken along the west coast of the Antarctic Peninsula and in Bransfield Strait show widespread occurrence of Bathylasma corolliforme nauplius larvae during the austral spring, mid-October to the third week of December. During autumn, between the first week of May and early June there was a complete absence of balanomorph nauplii. This evidence shows periodicity in reproduction. There is a seemingly close correlation between the presence of these nauplii and the published data on phytoplankton biomass and seawater surface temperature.
  • Technical Report
    Gregarious settlement by the larvae of Hydroides dianthus (Polychaeta, Serpulidae)
    (Woods Hole Oceanographic Institution, 1981-09) Scheltema, Rudolf S. ; Williams, Isabelle P. ; Shaw, M. A. ; Loudon, Catherine
    Larval development of the serpulid polychaete worm, Hydroides dianthus Verrill 1893 parallels that of other closely related species. The larvae prefer to settle upon surfaces already inhabited by other members of their own species rather than to colonize surfaces without such conspecific residents. However, very wide variations in the intensity of settlement are observed. These differences in the amount of settlement cannot presently be attributed to any single variable. Gregarious settlement appears to be typical for sessile species which do not have the ability to reproduce asexually after settlement.
  • Preprint
    Reproduction among protobranch bivalves of the family Nuculidae from sublittoral, bathyal, and abyssal depths off the New England coast of North America
    ( 2009-02-04) Scheltema, Rudolf S. ; Williams, Isabelle P.
    Protobranch bivalve species of the family Nuculidae pass either through a planktonic lecithotrophic larval stage or a direct non-planktonic development. Oogenesis of the three sublittoral species examined is synchronous. Deposition of egg masses by Nucula delphinodonta and spawning by Nucula annulata and Nucula proxima occurs only during summer months. Among the four bathyal and abyssal species, Ennucula similis, Ennucula granulosa, Deminucula atacellana, and Brevinucula verrilli, oogenesis is asynchronous and there is no discernable pattern of periodicity of spawning. Absence of periodicity in reproduction in these deep-sea species is confirmed by examination of individuals from dredge samples taken at different times of year. The median apparent fecundity among both sublittoral and deep-sea species is directly related to size (i.e., shell length) and age. Among the Nuculidae the median apparent fecundity is greater among sublittoral than bathyal and abyssal species. The geographic distribution of a species depends on its capacity to disperse. The dispersal of the planktonic lecithotrophic larvae of the sublittoral species Nucula annulata and Nucula proxima is limited to the continental shelf of the northwestern Atlantic by inshore bottom circulation and because these very small planktonic larvae (<2.5 mm) lack the capacity to move vertically upward through the water column into the offshore currents. On the other hand, the bathyal and abyssal species having lecithotrophic larvae have a very wide amphi-Atlantic distribution extending from 60°N to 40°S atitude along the North and South American coasts and from 55°N to ca. 19°S from off Europe southwards to the coast of West Africa as a consequence of dispersal by planktonic lecithotrophic larvae along the seafloor. The amphi-Atlantic dispersal must occur stepwise between deep-sea populations (e.g., off Greenland). Such a geographic distribution indicates a widespread dispersal and is supported by the genetic similarity that has been described between North American and western European populations of Deminucula atacellana.