Bornella anguilla Johnson, 1984 (48mm)
OPISTHOBRANCH OF THE WEEK
Opisthobranch of the Week Data
Frequency on Okinawa:
- Order: NUDIBRANCHIA
- Suborder: Dendronotina
- Family: Bornellidae
[brackets indicate range for all Okinawa-collected specimens of the species]
- Individual Collection No: RFB #3643-A
- Location: Horseshoe Cliffs, Okinawa (26o30.0'N, 127o50.9'E) [H/S Cliffs, Seragaki, Kadena Runway Lights]
- Date: 18 April, 1998 [Sep '89, Dec '91, Apr '94, May '94(2 indiv), Apr '98]
- Depth: 225ft (69m) [40ft, 190ft, 190ft, 210ft, 225ft, 225ft]
- Water temperature at collection depth: 71oF (22oC)
- Size: TL 48mm [22mm, 41mm, 44mm, 44mm, 48mm, 54mm]
- Specimen deposited: Cal Acad Sci: CASIZ #174983 (six additional specimens deposited at Cal. Acad)
- Photo Data: Kodachrome / 105mm Nikon (1:1.5 @ f/16)
Bornella anguilla is considered to be rare on Okinawa as I have collected a total of seven individuals over a period of more than thirty years of diving in okinawan waters. I have photographed three others of which specimens were not collected. Perhaps an additional half dozen others have been seen, primarily in water deeper than 55m, but were neither photographed nor collected. The above image shows the animal on a Plumularia hydroid from which it was collected. I've added a second page with images of four additional collected animals.
In as much as I haven't access to the original publication by Johnson (1984), I've taken the following information from Gosliner, et al (2008):
Identification: Bright and complex color pattern with orange and black paddle-shaped appendages adjacent to the gills and rhinophores.
Distribution: Known from the western Indian Ocean of South Africa Reunion, Madagascar to Myanmar, Thailand, Western and Eastern Australia, Vanuatu, Fiji, Papua New Guinea, Indonesia, Philippines, Guam, Japan, and the Marshall Islands.
There are a relatively large series of images of B. anguilla on Bill Rudman's Sea Slug Forum in the "Related messages" section.
As of late September, 2012 I've recorded three described species of Bornella from the waters of Okinawa's main island. These three animals are:
- Its name [anguilla = eel] refers to its method of swimming. While most species of Bornella can swim by a lateral flexion of their body, in B. anguilla a muscular wave travels down the body to produce an eel-like motion.
- Gosliner, T.M., D.W. Behrens, & Á. Valdés 2008. Indo-Pacific Nudibranchs and Sea Slugs. Sea Challengers, Gig Harbor, WA.
- Johnson, S. 1984. A new Indo-West pacific species of the dendronotacean nudibranch Bornella (Mollusca: Opisthobranchia) with anguilliform swimming behaviour. Micronesica, 19(1): 17-26. [for 1983]
- Rudman, W.B. Available via http://www.seaslugforum.net/find/bornangu.
Page Date: 24 Sep '12
Page Modification Date: 24 Sep '12
Digitally manipulated photo
Copyright © 2012 Robert F. Bolland