turbinate, umbilicate, with impressed sutures, and has 4.75 whorls. The spire is turreted and, in apertural view, slightly concave in outline. The last whorl is high, about three times the height (length) of the visible part of the penultimate whorl. The last whorl is shouldered. The shell surface is marked with fine growth lines, some of which are more prominent, becoming almost low, irregularly spaced, transverse riblets, and with fine, close-set, raised, spiral striae. The aperture is rather widely adnate to the surface of the last whorl.
There are three major teeth in the shell aperture. The parietal and angular lamellae are well separated; the parietal lamella is the best dest developed of the apertural teeth; the angular lamella is developed but not complete, its outer end is near the edge of the peristome; the infraparietal lamella is a small tubercle. The columeller lamella is well developed, straight and horizontal; the subcolumellar lamella is a small, strong tubercle. The upper palatal plica is short, tubercle-like, and is located at the edge of the peristome; the two interpalatal plicae are a little deeper-set in the aperture; the upper interpalatal plica is about twice the size of the lower interpalatal plica; the lower palatal plica is the largest of the palatal plicae. The basal plica is a reduced, low, subobsolete tubercle.
Paraboysidia tamphathai occurs at Tam Pha Thai National Park, Lampang Province. The species name is after the name of the national park.