“A species of the subgenus Opisthostoma with a raised apex and abbreviate cylindrical shell, in which the last whorl reverses its direction of growth and ascends the spire so that the outer peristome encapsulates the apical whorls. A short longitudinal indentation occurs in the last whorl just beyond the constriction. The sculture consists of sparse feeble axial ribs. Spiral sculture is absent.” (Thompson, 1978)
Thompson (1978) original descriptions on Opisthostoma (Opisthostoma) holzmarki – “Shell minute, less than 1 mm in height, and slightly more so in width. Nearly opaque, whitish. Narrowly umbilicate. The spire is abbreviate cylindrical and is partially covered by a strongly distorted last whorl. The spire consist of 4 whorls. The embryonic whorl lies at a plane slightly oblique to the shell axis. The apical 2 whorls are low and convex in outline and protrude above the third whorl for a distance about equal to the calibre of the third whorl. The body whorl (fourth whorl) is narrower but slightly larger in calibre and is constricted below the aperture. The body whorl reverses its direction of coil on the side of the shell and ascends the spire to the shoulder of third whorl. The outer peristome continues over the apex by being appressed against the side and top of the first 3 whorls. At the point of constriction the body whorl bears a short narrow longitudinally impressed groove along the periphery. The sculpture of the postembryonic whorls consists of sparce, low, narrow axial ribs that are most distinct below the periphery of the last 2 whorls and continue undiminished into the umbilicus. There are 23 ribs on the penultimate whorl. Spiral sculpture is absent. The aperture faces obliquely upward. The outer peristome consists of several high laminations and is uniformly wide excapt where it is broadly expanded over the apex of the shell. The inner peristome is thicker and flares out nearly uniformly, except where it is appressed to and extends slightly forward on the penultimate whorl.”
By Vermeulen (1994)
"Shell white, approximately opaque or slightly translucent. Whorls 3- 3 3/8 (tuba not included); top whorls slightly to moderately oblique, somewhat elevated; body whorls forming a cylindrical body, convex, the upper body whorl sometimes slightly angular, with the suture well impressed. Constriction rather distinct, a sharp furrow, with an equally sharp, longitudinal furrow on the tuba immediately in front of the constriction. Tuba consisting of 1/2 whorl, touching the body whorls over its entire length, approximately circular in section. Shell with thin radial ribs, which are moderately spaced and low on the upper body whorl (19-27 ribs present on this whorl), approximately similar but distinctly wider spaced on the lower body whorl and over the area of the constriction (sometimes absent on the latter), and moderately to widely spaced and slightly more prominent on the tuba. Ribs usually crossed by fine spiral striation. Umbilicus approximately closed. Aperture with the imaginary plane through the inner peristome tilted up to 30 degrees with regard to the coiling axis of the body whorls; with the upper margin distanctly protruding beyond the plane perpendicular to the coiling axis of the body whorls as well as through the apex; widely ovate; apertural teeth absent; inner peristome somewhat thickened, somewhat reflected; outer peristome flaring on the palatal side, on the parietal side widely and obliquely expanded and enveloping the top whorls of the shell. Constriction inside often with an inconspicuous, short transverse furrow on the outer surface, as well as with a transverse furrow inside, corresponding with the swelling of the tuba beyond the transverse furrow outside. No parieto-basal tooth present. Height of body whorls 0.8-0.9 mm; width including tuba 0.9-1.1 mm, without tuba 0.7 mm; height of aperture 0.5 mm; width of aperture 0.5-0.6 mm."
Opisthostoma (Opisthostoma) holzmarki – “Measurement of the holotype: height of shell, 0.97 mm; major width, 1.07 mm; minor width 0.71; aperture width, 0.53 mm; aperture height, 0.50 mm. Measurement of the 3 paratypes: height of shell, 0.74, 0.83, 0.74 mm; major width, 1.06, 1.10, 1.01 mm; minor width 0.74, 0.83, 0.74; aperture height, 0.53, 0.51, 0.48 mm.” (Thompson, 1978)
Type locality – “Borneo; Sarawak; Fourth Division; limestone hill on the trail from the Niah River to Niah Cave, Batu Niah” leg. W. I. Holzmark/Nov. 4, 1976 (Thompson, 1978)