Asthenosoma ijimai Yoshiwara, 1897 (photo only, size unrecorded)

Featured Invertebrate Data


Frequency on Okinawa: Collection Data:
[brackets indicate range for all Okinawa-collected specimens of the species]

Species Account:

        The Magnificent Fire Urchin, Asthenosoma ijimai, is considered to be uncommon on Okinawa. Unfortunately no specimens have been collected by myself but various animals have been seen and photographed (less then ten individuals photographed) on an occasional basis over numerous years of Okinawa diving. The entire group of Asthenosoma species is taxonomically difficult. In re a recent message from Rich Mooi at Cal Acad Sci he points out the following:

"I find the Asthenosoma group to be rather challenging myself -- even in the case of living specimens. And then there is the addition of Asthenosoma intermedium to the mix. That species aside, which I have not identified positively from any material myself, there is color variation, and when that happens, the difficulties just deepen more. To be really certain, you need to look at the relationship of the madreporic pores to the plating in the apical system, and in peculiarities of the pedicellariae -- hardly things you can see from most photos."

I've been stung several times by this toxic echiuroid, and after my initial encounter with the painful stings, I took pains (pun intended) to avoid additional contacts. Perhaps easier said than done. At depth during relatively deep dives, while turning coral rubble I've inadvertently touched one of these and even w/ gloves, have received a good stinging jolt. Note to self: Don't ever do this again!

Shawn Miller (2017) points out a bit of information about both the stings and treatment.

The fire urchin is the most beautiful sea urchin found in Okinawa. Its beautiful colors attract divers to pick it up. The spines inject venom which cause extreme pain and discomfort.

First aid: Remove visible spines. Wash with soap and water. Pain control if needed - hot water (113 F / 45 C) or use hot packs. Seek medical treatment if spines have entered the joints.

There are several excellent photographs of A. ijimai found on-line, several of these are:

Ryan Photographic - Echinoidea - Sea Urchins


  • Yoshiwara (1897) did not specifically mention the etymology in his publication but he possibly(?) chose the specific name (ijimai) in honor of Prof. Ijima, based upon a single specimen purchased by Prof. Ijima from a Jögashima fisherman.

Literature Cited:

  • Miller, Shawn Miller (2017). Okinawa Nature Photography. http://okinawanaturephotography.com/tag/scubadiving-in-okinawa/.
  • Yoshiwara, S. 1897. On Two New Species of Asthenosoma from the Sea of Sagami. Annotationes Zoologicae Japonenses 1, 5-11.

        I've added a second page w/ a series of images of the species.

        In addition, I've also added a link to the current and past featured invertebrates via a list and thumbnails.

Page Date: 01 Nov '17
Page Modification Date: 01 Nov '17
Digitally manipulated photo
Copyright © 2017 Robert F. Bolland