A hard white ridged network with orange lines running along the crests.
A firm-bodied dorid to about 6 cm, translucent white with a raised network of ridges over the back, each crest carrying a line of bright orange-yellow, and the mantle margin edged in the same colour. The rhinophores and gill are dark orange to brown-black. The body is noticeably harder than that of a chromodorid, which is typical of the genus, and the ridge pattern is the identification: several Halgerda occur here, and they are separated on the arrangement of the ridges and the colour of the lines along them.
Named for Batangas in the Philippines, where it was described, and found through the central Indo-Pacific. Feeds on sponges. Recorded from about 5 to 30 m on rubble and rock, usually out in the open on the sponge it is eating rather than under cover. Slow-moving and firm enough to hold its shape, which makes it a straightforward subject; the difficulty is that the white body blows out easily on flash, and the orange ridge lines are lost with it if the exposure is set for the sand around it.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
