, Volume 440, Issue 1, pp 191–198

Semper's (zoanthid) larvae: pelagic life, parentage and other problems

  • Authors
  • J. S. Ryland
  • Samantha de Putron
  • R. S. Scheltema
  • P. J. Chimonides
  • D. G. Zhadan

DOI: 10.1023/A:1004171127777

Cite this article as:
Ryland, J.S., Putron, S.d., Scheltema, R.S. et al. Hydrobiologia (2000) 440: 191. doi:10.1023/A:1004171127777


Semper's larvae were obtained from <300 out of ∼1800 plankton tows taken in the world's oceans (1964–1993). Zoanthellae (larvae of Sphenopidae) occurred at 217 stations and zoanthinae (larvae of Zoanthidae) at 86, the two larval types showing distributions clearly delimited by a minimum sea temperature (∼22 °C for zoanthellae, ∼18 °C for zoanthinae; a statistically significant difference, P<0.001). Length of formalin-fixed zoanthellae was ∼2–8.6 mm and of zoanthinae ∼1.5–5.9 mm. Endodermal zooxanthellae were present in 9/24 zoanthinae but in no zoanthellae (of 19). Three larvae contained an endo-commensal/parasitic amphipod. Septa were externally visible in larger zoanthinae and were counted in transverse sections of other larvae, a majority of which (both kinds) had 12 septa, the normal maximum. The pattern was brachycnemic in 40/43 larvae and anomalous (but non-macrocnemic) in three. If macrocnemic genera reproduce by Semper's larvae, they should have been represented in such a large sample. The distribution of adult Epizoanthus was examined: many species are deep sea (recorded down to ∼5000 m) but shallow-water species are relatively plentiful in, for example, the Adriatic and North Seas. No Semper's larva has ever been recorded from either. Some Parazoanthus species also occur in shallow water, especially associated with western Atlantic reef sponges. If they produce Semper's larvae, these have never been found. It is probable that macrocnemic zoanthids settle from planulae that do not develop into recognizable zoanthellae or zoanthinae.

larval typesdistributionssea temperaturezooxanthellaedeep seaEpizoanthus

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© Kluwer Academic Publishers 2000