Bornella stellifer

Photo courtesy of Webmaster
Seraya Resort
Tulamben, Bali, Indonesia

Bornella stellifer (Adams & Reeve, 1848)

Members of the genus Bornella are very interesting beasts. On Halloween Mike’s Branch of the Week was Bornella anguilla. While Bornella have many similarities in shape and natural history to the aeolids, they certainly belong to the Dendronotina. They have aeolid-like ceratal structures on each side of its elongate body and they feed on hydroids. The so-called cerata do not have cnidosacs, like aeolids, and if you look closely, they have strange, almost dorid-like gill tufts at the base of each of these structure.

The name Bornella stellifer refers to another interesting structure found in this group – a pair of starlike (hense – stellifer for starlike) or palmate sensory oral tentacles. The rhinophore is a long stalk which bears a ring of long pointed papillae, around the base of the clavus.

Nishina Masayoshi’s note to the Sea Slug Forum titled Bornella mating provides several great photos of a copulating pair. One of his photos is very interesting showing of a series of spines in the genital opening. I believe these spines grip the penis of each inidvidual in a copulating pair to hold then together in surgy conditions ensuring successful exchange of gametes.

Specimens are up to 80mm in length and known from throughout the Indo-Pacific.

Regina and staff at Seraya Resort
Bali, Indonesia

Well, it was during a night dive in front of Seraya Resort that someone was persistenly tugging at my shoulder while I was in the middle of photographing a branch just found. I took one last look at the branch to fix the position and looked up to see who was pestering me. Well, it was none other than my daughter Regina, our newly certified diver who was indicating that I should follow her and see what she found. Mind you, this was her second night dive! Well, lo and behold, I couldn't believe what she was pointing to! I didn't recognize this guy beyond knowing that it was new to me. I spent the next 10 mintues taking digital image after image of this strange guy! Getting back in after the dive and hitting the books, we able to put a label on the strange branch within minutes. It certainly stands out so as to say! Its more than obvious that there is an up and coming new brancher in the family. When she's not working or studying, I can certainly see her at my side exploring the wonderful world of sea slugs.

Enjoy also, a streaming slide show from the trip!

For all you branchers, I would certainly recommend Seyara Resort as a stop in the Tulamben area. The resort is up the road about 5 minutes from Tulamben. If this sounds like a plug, you're right, but albeit it, one that was not solicited or paid for! I really liked the place!

David W. Behrens Author: Pacific Coast Nudibranchs Co-Author Coral Reef Animals of the Indo Pacific Proprietor of Sea Challengers Natural History Books Send Dave mail at dave@seachallengers.com

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