Polar Biology

, Volume 30, Issue 2, pp 243–248 | Cite as

A scanning-electron microscopic study of Dickdellia labioflecta (Dell, 1990) (Gastropoda, Littorinoidea) on Colossendeis megalonyx megalonyx Fry and Hedgpeth, 1969 (Pycnogonida, Colossendeidae): a test for ectoparasitism

  • Tobias LehmannEmail author
  • Juan P. Gailer
  • Roland R. Melzer
  • Enrico Schwabe
Original Paper


A scanning-electron microscopic (SEM) study of a clutch of eggs and juveniles of Dickdellia labioflecta on Colossendeis megalonyx megalonyx revealed that the young snails remove the upper layers of the pycnogonid cuticle, most probably by rasping. This way holes are created in the cuticle that could serve as a potential source of food for the snail. Measurements and statistics show that the holes have the same density as the cuticular glands. These glands are spread all over the pycnogonid cuticle. Additionally, they are filled with cytoplasmic material having a fine structure and cuticular surrounding that is typical for those glands. Hence, it is suggested that the snails get access to the interior of the pycnogonid through the holes and glands. Holes in the cuticle are absent under smaller Dickdellia specimens, but they are formed consecutively as they become older and grow larger. It is suggested that Dickdellia snails are ectoparasites because this would allow them to remain on pycnogonids until they exceed the initial egg volume, which would be difficult to explain without additional food uptake from the pycnogonid host.


Attachment Site Shell Diameter Cytoplasmic Material Contralateral Tibia Size Series 
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Dr. Michael Schrödl (Zoologische Staatssammlung München, Germany), the sorting teams, and the crew of RV “Polarstern” are warmly thanked for their professional work. Maria Montoya (Munich) kindly determined the Colossendeis pycnogonid. Special thanks go to Nicolas Straube (Munich) for giving us help with the statistics and Stefan Schmidt for improving the English. This is ANDEEP contribution No. 56.


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Tobias Lehmann
    • 1
    Email author
  • Juan P. Gailer
    • 1
  • Roland R. Melzer
    • 1
  • Enrico Schwabe
    • 1
  1. 1.Zoologische StaatssammlungMunichGermany

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