Bonisa nakaza

Photo courtesy of Wilhelm Van Zyl
Falsebay, South Africa

Bonisa nakaza Gosliner, 1981

Bonisa nakaza is truly one of the most beautiful of the members of the family Zephyrinidae, although one must admit, most of the members are gorgeous. The genus Bonisa was erected to differentiate B. nakaza from other species of Janolus. Species of Bonisa differ from Janolus in lacking branches of the digestive gland in their cerata. Bonisa is named in dedication of Terry Gosliner’s (the describer) wife, Bonnie.

Wilhelm’s photo above taken in Falsebay, South Africa actually shows both of the common color phases of this variable species . On the average the lower portion is yellow with blue towards the tip. Some have a subapical internal concentration of black or dark blue pigment. In other animals, as seen above, the blue pigment is absent from the cerata, which are translucent white with a yellow or orange tip.

Like other zephyrinid’s Bonisa has a prominent carnacle, a cock’s comb like organs between the rhinophores. Biologists ponder its function today. This would be a great student project.

In case you were wondering, as Valda Fraser was on Bill Rudman’s Forum, “nakaza” is a Zulu word meaning - to adorn with beautiful colors. Obviously Terry intended the name for the species bright coloration, and for that of Bonnie’s own beauty.

B. nakaza feeds on the heavily calcified bryozoan Tubucellaria levinseni and is found from the shallow waters to a depth of about 90 feet. It reaches a length of 10cm as an adult. This species is known from the Cape Peninsula to Port Elizabeth, South Africa; both Atlantic & Pacific coasts.

Dave Behrens
Danville, Calif
Jun. 2005

Wilhelm Van Zyl

My name is Wilhelm van Zyl; I am 29 years of age. I live in Cape Town, South Africa.

I have been SCUBA diving since 1997, and have an advanced openwater certification and also a Class IV commercial qualification needed to do any underwater work in South Africa. I also enjoy other underwater sport namely freediving, spearfishing and underwater hockey (anything you can do with a mask and snorkel!).

I studied BSc at the University of Port Elizabeth in the Eastern Cape. I majored in Zoology and Geology and went on to do my Honers degree in Geology. I am currently working as a geologist in the offshore diamond mining industry. (No diving involved).

Because I work offshore I have 4 weeks shore leave for every 4 weeks work. During this time I try to dive as often as possible, mostly in the False Bay area close to Cape Town. Last year I went to Thailand for a month long diving holiday. Although I always loved nudibranchs, this is really where I started photographing them. In my spare time I also volunteer at the Two Oceans Aquarium in Cape Town, cleaning windows in the predator and kelp tanks.

The camera I am using is a Cannon A80 with Cannon underwater housing. As I do not have an external strobe I am limmited to takeing macro shots. But as I really like nudibranchs this is not such a big problem.

Wilhelm Van Zyl

Send Wilhelm email at

Puerto Vallarta, Mexico
March 2005

Ali Hermosillo and Dave 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

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