Polar Biology

, Volume 33, Issue 9, pp 1205–1214 | Cite as

Postembryonic development of Nymphon unguiculatum Hodgson 1915 (Pycnogonida, Nymphonidae) from the South Shetland Islands (Antarctica)

  • Esperanza Cano SánchezEmail author
  • Pablo J. López-González
Original Paper


Male specimens of the sea spider species Nymphon unguiculatum, carrying eggs, larvae and postlarvae in various stages of development, were collected off the South Shetland Island at water depths between 112 and 472 m in austral summer 2006/2007. Here, we describe the external morphology of four postembryonic stages (protonymphon, instar 1, instar 2, and instar 3) carried by these specimens. We found that (1) protonymphon larvae hatch from the eggs; (2) larvae and postlarval stages have yolk reserves and are characterized by a relatively large size (average body lengths of 0.46, 0.55, 0.65 and 0.73 mm in the successive stages); (3) postlarvae remain on the ovigerous legs of males during several moults; (4) a spinning apparatus is present; (5) the development of walking legs is sequential. The larval and postlarval development of N. unguiculatum is compared with that known from other pycnogonid species.


Pycnogonida Nymphonidae Nymphon unguiculatum Postembryonic development Protonymphon 



The authors would like to thank the valuable assistance of the officers and crew of the R/V Polarstern, and many colleagues on board during the Polarstern ANT XXIII/8 cruises. We take this opportunity to extend our thanks to the cruise leaders and steering committee of the cruises, especially Julian Gutt (Alfred Wegener Institut, Bremerhaven) and Enrique Isla (Instituto de Ciencias del Mar, CSIC, Barcelona), who kindly facilitated the work on board and for the opportunity to collaborate in this Antarctic programme. We also acknowledge Marika di Meglio for her assistance during the first moments of this study. Support for this work was provided by the Spanish CICYT project POL2006-06399/CGL (CLIMANT). Mr. Tony Krupa is thanked for reviewing the English version.


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Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Esperanza Cano Sánchez
    • 1
    Email author
  • Pablo J. López-González
    • 1
  1. 1.Biodiversidad y Ecología de Invertebrados Marinos, Departamento de Fisiología y Zoología, Facultad de BiologíaUniversidad de SevillaSevillaSpain

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