Opisthobranch of the Week Data
Cadlinella subornatissima is considered to be very rare on Okinawa as I have seen and collected only the above featured animal. The animal was found in 120ft near the base of a vertical rock wall at the reef edge; the wall was covered with numerous cnidarians, bryozoans, and poriferans. The above image is of less than good quality, but it's the best I have of several available images. Tomohiko Kurihara has an excellent image of C. ornatissima, on his Nudibranch Site (a 15mm animal from 37m, photographed from mainland Japan). Tomohiko's site is in Japanese, but with Latin scientific names.
I've found only one other described species of Cadlinella here on Okinawa's main island, C. ornatissima. I do however have two currently undetermined specimens which may turn out to be C. hirsuta Rudman, 1995.
Cadlinella ornatissima was described by Baba (1996) from nine
specimens, all collected from Suruga Bay, Shizuoka Prefecture, Japan.
The following description of external morphology and color is taken from Baba's 1996 paper:
The external morphology of this new species is almost identical to Cadlinella ornatissima (Risbec,1928). The body is spiculose on account of interwoven spicules. There are numerous large and small tubercles scattered on the dorsum, the central tubercles being usually larger than the marginal ones. When alive, the larger ones of the dorsal tubercles rise to form typical club-shaped papillae with tapering or rounded tips. These papillae do contain spicules and they are only slightly contractile. Each of the rhinophoral sheaths has paired, inner and outer papillae. The gills are formed of 5, simple to bipinnate plumes. The margin of the branchial cavity is entire. The under side of the mantle flange is closely speculate. The mantle glands on the margin of the mantle are simple, and not compound as in Cadlinella ornatissima. The oral tentacles are triangular with an external groove.
The general coloration of Cadlinella subornatissima n. sp. is also very similar to that of C. ornatissima. However, as my friend Mr. Iwao Hamatani has personally pointed out, C. subornatissima n. sp. is consistently different from C. ornatissima in the following way. In C. ornatissima, the whole surface of the dorsum is yellow. In C. subornatissima n. sp., only the central part of the dorsum is yellow, the marginal part of it being white. In C. subornatissima n. sp., most of the larger papillae on the dorsum are opaque white turning to pinkish red at the tips, and the smaller papillae are opaque white altogether. In C. ornatissima, all of the dorsal papillae are opaque white subterminally, and pinkish red at the tips. In C. subornatissima n. sp., the mantle glands scattered along the margins of the mantle are recognizable as opaque white spots. Both the rhinophores and gills are colorless. The underside of the mantle flange and the foot sole are also colorless.
By the name subornatissima, it is meant that Cadlinella subornatissima n. sp. is next to C. ornatissima in possessing the papillate dorsum and in the anatomy of the genital system. But they are distinguished by the possession of a different color pattern on the dorsum and a different structure to the first lateral tooth of the radula. Also the radula of subornatissima is larger than that of ornatissima.