Sinoennea tweediei Tomlin, 1941
“This may be known from hungerfordiana by its broader and more flattened shape and by the greater projection of the last whorl.” (Tomlin, 1941)
“The specimens from Gua Badak are on the average a little smaller, with a narrower umbilical opening and a less pinched keel at the base. These features are not important enough to separate these shells taxonomically.” (Benthem-Jutting, 1961)
Tomlin (1941) original descriptions on Sinoennea tweediei – “A very broad shell, flattened at the apex, not at all unlike hungerfordiana Mllff. with the entire aperture much more thrown forward even than in that species. There are seven whorls, two of them constituting a smooth protoconch, the other five with regular, somewhat retractive axial riblets, of which there are about thirty-two on the antepenultimate whorl; this whorl is broader and more swollen than the rest; suture shallow; umbilicus large and deep, with the last whorl keeled round it; aperture patulous, elongate with a parietal and a pointed tooth on the outer labrum all but meeting, and forming a sort of auriform pocket in the upper right hand corner; there is a deep-set blunt tubercle at the back of the labial tooth.”
Benthem-Jutting (1961) descriptions on Sinoennea tweediei – “Shell short, ovoid-pupoid, with low, but pointed apex. Glassy white, transparent, with rather widely spaced transverse ribs, 35 on the last whorl of the holotype in the British Museum (Natural History). Just behind the peristome about five ribs are standing somewhat closer together. No spiral striation. Whorls 6-7; the holotype has 6 whorls. First two smooth, subsequent ones ribbed. Profile of the whorls convex. At a short distance from the aperture the last whorl is somewhat compressed laterally, with a slight crest-like transverse inflation. Last part of last whorl free, trumpet-shaped for about ½ mm. periphery of first four whorls rounded, of nos. 5 and 6 flattened. Last whorl higher, but narrower than the preceding one. The 5th whorl is somewhat overhanging in the shell profile. Suture well impressed. Umbilicus open, wide, angular by the lateral compressing of the last whorl. Aperture almost vertical, long-oval. Peristome free, continuous, forming an oblique sinus at the upper outer margin. All margins thickened and reflected. The lower wall of the marginal sinus projects into the aperture, forming a blunt tooth in the interior and a groove or pit in the exterior side. Below this tooth a second knob is deeply seated at some distance from the peristome. Columellar side with a vertical lamella deep in the aperture. The reflected peristome edge can develop a low tooth (as in the figure), but is smooth in other cases. Between the palatal tooth and the free end if the parieto-angular lamella there is only a very short distance.”
Sinoennea tweediei – “Long. 3.40 mm; diam max. 2.50 mm.” (Tomlin, 1941); Sinoennea tweediei – “Dimensions: Height 2.7-3.3 mm; Width 1.6-1.9 mm; Height of aperture 1.1-1.3 mm.” (Benthem-Jutting, 1961)
Type locality – “Lenggong, Perak” (Tomlin, 1941)
Other localities – “Malaya; Gua Badak near Lenggong, Perak” (Benthem-Jutting, 1961); “Malaya; 1 mile North of Gua Badak near Lenggong, Perak” (Benthem-Jutting, 1961); “Malaya; Gunong Tasek, near Lenggong, Perak” (Benthem-Jutting, 1961)