Pleurobranchus garciagomezi
February 16, 2002
From: Dr. Peter Wirtz
Dear Bill,
I hope you are well. I just browsed through a number of most useful pages in the Sea Slug Forum. Coming across the message on the pleurobranch from the Canary Ids identified as P. garciagomezi, I realized I should probably send you a pdf of a paper on this species (which is I think is not P. garciagomezi), plus a photo of the true P. garciagomezi (Fontes, Tempera & Wirtz, 2001).
PHOTO: Tarrafal, northwestern coast of São Tiago Island, Cape Verde Islands. Photo: P. Wirtz.
Here is a slightly edited section from that paper discussing the differences between Pleurobranchus sp and P. garciagomezi:
While snorkelling at night in a large tidal pool at Varadouro, western coast of Faial Island, in September 1999, a large … Pleurobranchus Cuvier, 1804 was encountered. The animal, [same as illustrated in Forum from Canary Islands], had a body length of approximately 7 cm. It obviously belongs to the same species as the animal from the Canary Islands (Wirtz, 1995, page 163 top), and from Madeira Island (Wirtz 1999, plate 2, photo number 5). Cervera et al. (1996) summarised the knowledge about the Mediterranean and eastern Atlantic Pleurobranchus species and described Pleurobranchus garciagomezi from the Cape Verde Islands. L. Cervera (personal communication to PW) suggested that the species from the Canary Islands and Madeira could be a colour morph of P. garciagomezi. This view was shared by Malaquias (2000) who apparently found the same species at the Selvagens Islands (a small group of islands between the Canary Islands and Madeira). The photo posted in this message shows a colour photo of P. garciagomezi taken at Tarrafal, northwestern coast of São Tiago Island, Cape Verde Islands. I believe that the opisthobranch shown in Erwin Koehler's message is an undescribed species of the genus Pleurobranchus. It differs from P. garciagomezi not only in its colour pattern but also in body shape and behaviour: while Pleurobranchus garciagomezi from Cape Verde has conspicuous white lines on a cream-coloured to dark brown smooth body, Pleurobranchus sp. has a much denser network of much thinner pale lines on an orange-coloured slightly rugose body. The body shape of Pleurobranchus sp. is more ovoid and higherbacked than that of P. garciagomezi. The Pleurobranchus sp. captured at the Azores is larger than any P. garciagomezi recorded so far (the maximum size of P. garciagomesi given by Cervera et al. (1996) is 5 cm). Finally, P. garciagomezi is a day-active species that can commonly be seen on open substrates throughout the day at the Cape Verde Islands (personal observations by the third author during ca. 60 dives between 1988 and 2000), whereas the two Pleurobranchus sp. from Madeira and the Azores were active at night and never encountered in about 1000 dives during the day (between 1983 and 2000) in these two archipelagos.
References
• Cervera, J.L., R. Cattaneo-Vietti & M. Edmunds 1996. A new species of Notaspidean of the genus Pleurobranchus Cuvier, 1804 (Gastropoda, Opisthobranchia) from the Cape Verde Archipelago. Bulletin of Marine Science 59 (1): 150-157
• Fontes, J., Tempera, F. & Wirtz, P. 2001. On some interesting opisthobranchs (Mollusca, Gastropoda) from the Azores. Arquipélago. Life and Marine Sciences, 18A: 85-87.
• Malaquias, W.A.E. 2000. Additions to the knowledge of the opisthobranch molluscs of Selvagens Islands, NE Atlantic, Portugal. Arquipélago. Life and Marine Sciences. Supplement 2 (A): 89-98.
• Ortea, J., L. Moro, J.J. Bacallado & J. Espinosa 1999. Catálogo abreviado de las espécies del orden Sacoglossa (= Ascoglossa, Mollusca: Opisthobranchia) de las islas Canarias y de Cabo Verde. Revista de la Academia Canaria de Ciencias 1998 10 (4):85-96.
• Schmekel, L. & A. Portmann 1982. Opisthobranchia des Mittelmeeres. Nudibranchia und Saccoglossa. Monografia della Stazione Zoologica di Napoli 40. Springer-Verlag, Berlin. I-x + 410 pp., 122 figs. 36 pls.
• Weinberg, S. 1993. Découvrir la Mediterranée. Éditions Nathan, Paris. 352 pp.
• Wirtz, P. 1995. Unterwasserführer Madeira Kanaren Azoren Niedere Tiere – Underwater Guide Madeira Canary Islands Azores Invertebrates. Naglschmid, Stuttgart. 247 pp.
• Wirtz, P. 1998. Opisthobranch molluscs from the Azores. Vita Marina 45 (1-2): 1-16.
• Wirtz, P. 1999. Opisthobranch molluscs from the archipelago of Madeira. Vita Marina 46 (1-2): 1- 19.
Cheers!
Peter
Madeira, Portugal
biomar@dragoeiro.uma.pt
Wirtz, P., 2002 (Feb 16) Pleurobranchus garciagomezi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6214Thanks Peter,
Thanks for sorting that out for me. I'll call the unnamed species Pleurobranchus sp. 1. Any other photos and explanatory notes from your part of the world are always welcome. There are so many local publications available these days that it is very difficult to keep up with all the published work. Over a 1000 visits are made to the Forum every day [over 5000 pages accessed] so posting information on the Forum is a good way to spread information which would otherwise be restricted to a small local audience.
Best wishes,
Bill Rudman
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