Roseaplagis caelatus

Roseaplagis caelatus is a species of small sea snail in the family Trochidae, the top shells.

Description
It is smaller than Cantharidus sanguineus (height: 5.5 mm, diameter 4.5 mm) but it is more deeply ribbed and its grooves are wider. The imperforate shell is more deeply ribbed, and the ribs narrower. They number 5 to 7 on the penultimate whorl, 15 to 16 on the body whorl. Sometimes they are obsoletely granose through being crossed by growth lines. The columella shows a slight swelling in the middle.

Distribution
This marine species is endemic to New Zealand and occurs off the Foveaux Straits; Port Pegasus, Stewart Island; Snares and Bounty Islands

Subspecies
The former subspecies have been named:
 * Micrelenchus caelatus archibenthicola Dell, 1956 : synonym of Cantharidus caelatus mortenseni Powell, 1933 ; synonym of Roseaplagis mortenseni (Odhner, 1924)
 * Micrelenchus caelatus bakeri Fleming, 1948 : synonym of Roseaplagis artizona A. Adams, 1853 (Odhner, N.H.J., 1924)
 * Micrelenchus caelatus elongatus (Suter, 1897) : synonym of Cantharidus caelatus elongatus (Suter, 1897) ; synonym of Roseaplagis artizona A. Adams, 1853
 * Micrelenchus caelatus morioria Powell, 1933 : synonym of Cantharidus caelatus mortenseni Powell, 1933 ; synonym of Roseaplagis mortenseni (Odhner, 1924)
 * Micrelenchus caelatus mortenseni (Odhner, 1924) : synonym of Roseaplagis mortenseni (Odhner, 1924)