Opisthobranch of the Week Data
Chromodoris alius is considered to be very rare on Okinawa as I have collected only four individuals since the initial collection was made during May of 1989. The animal was found during a SCUBA excursion; discovered as it was crawling in the open amid a live stony coral reef during a high (198cm) daytime spring tide.
The only other Okinawan chromodorids apt to be confused with Chromodoris alius are the similar-appearing C. rufomaculata and C. aureopurpurea. Rudman (1987) originally described the species based on two specimens (the holotype* from Tanzania and the second, the paratype*, from Réunion Is.). Rudman chose the specific name as it means "another", having reference to the close appearance between two additional similar appearing species, Chromodoris aureopurpurea, and C. rufomaculata. Rudman points out the two similar species (i.e., C. alius and C. rufomaculata) are difficult to separate on external coloration.
*holotype & paratype: See "Type" Dictionary for explanation.