Elongate polar bodies of Conualevia alba

March 22, 2007
From: Jeff Goddard

Hi Bill,

Here are some images of a bizarre developmental phenomenon I've never observed before. At about the time of gastrulation, a majority of the polar bodies of Conualevia alba elongate, stretching from their original spherical shape and diameter of about 8 - 10 microns, to 35 microns in length, and in one case, to 73 microns.

Locality: Monterey Bay, California, USA, Pacific Ocean, October 2006. Photographer: Jeff Goddard.

This is pure speculation, but it's as if the polar bodies parallel the activity of the micromeres during gastrulation, but unconfined by neighboring cells, grow these tendrils. I have no idea what the significance of this is - if there is any at all - but did observe it in the two out of two egg masses; perhaps it will interest a developmental biologist.

I found one mention in the literature of this for a nudibranch. Trinchese (1880) described a similar phenomenon in the aeolid Cuthona caerulea.

• Trinchese, S. (1880). I primi momenti dell'evoluzione nei Molluschi. Atti della Reale Accademia dei Lincei Memorie ser 3. 7, 3-54.

Best wishes,
Jeff

goddard@lifesci.ucsb.edu

Goddard, J.H.R., 2007 (Mar 22) Elongate polar bodies of Conualevia alba. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/19684

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