The last 2-3 years have been a hay day for the description of new Halgerda's . Between the Clay Carlson and Patty Jo Hoff and the Shireen Fahey and Terry Gosliner teams, I lost count at about 16 or more newly named species. Branching buddy Bob Bolland first collected this species back in 1995 in 175 feet of water off Seragaki, Okinawa, his favorite dive site. Since that time he has collected it, one of twelve species of Halgerda found in Okinawa, often.
Halgerda okinawa was depicted in Coral Reef Animals of the Indo-Pacific on page 160 as Halgerda sp. from the Lembeh Straits of Indonesia. Marc's fantastic photo shown above is a spectacular example of the species, from this locality. It has also been documented from the Straits by photos taken by Carine Schrurs and Constantinos Petrinos. My good buddy "Con" reports that "During a dive at a dive site called NUDI RETREAT we located several Halgerda okinawa within an area of 10 meters at a depth of 42.5 meters."
As Bill Rudman points out on the Sea Slug Forum that the Indonesia specimens match the color of the Okinawan type specimens except for the absence of the black lines on the ridges. He suggests that the broken black rings near the mantle edge, which are so well developed in this Indonesian animal, seem to definitely link it to the Okinawan animals, one of which shows markings which could easily be derived from these rings.
Halgerda okinawa is a large species reaching over 125 mm in length. On Bob's Okinawan Slug Site , he has added a page with photos of the holotype and paratypes . Comparing the photos from Indonesia with Bob's page shows the variation in this species quite well.
Reference materials (for the hard cores):
Carlson, C.H. & P.J. Hoff. 2000. Three new Pacific species of Halgerda (Opisthobranchia: Nudibranchia: Doridoidea). The Veliger 43(2):154-163.
Fahey, S. J. & T. M. Gosliner. 1999. Preliminary Phylogeny of Halgerda (Nudibranchia: Halgerdidae) from the Tropical Indo-Pacific, with descriptions of three new species. Proceedings of the California Academy of Sciences 51(11): 425-448.
Gosliner, T.M., D.W. Behrens & G.C. Williams. 1996. Coral Reef Animals of the Indo-Pacific. Sea Challengers, Monterey, California.
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David W. Behrens
Pacific Coast Nudibranchs
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