Geotrochus bongaoensis (Smith, 1894)
“This species appears to be the same as that identified by Möllendorff as a variety of T. conicoides (Metcalfe), to which he gave the name var. crenulata. It is, however, very distinct from that Bornean species in size and form. It more nearly approaches T. paraguensis, Smith, from Palawan, but is easily separable by comparison. It is smaller, darker in colour, the whorls are less convex, the suture less obvious, and the spire more convex. The aperture also is of a somewhat different form, and the basal margin of the peristome is rather more tortuous but similarly thickened. I have not adopted the varietal name crenulata for this species in case it may be different from that described by Möllendorff, and moreover, it does not seem particularly applicable, the crenulation at the keel being so very feeble.” (E. A. Smith, 1894)
E. A. Smith (1894) original descriptions on Trochonania bongaoensis – “Testa depressa, orbicularis, acute carinata, imperforate, fusca; spira breviter conica, vix convexiuscula; anfractus 7, planiusculi, supra suturam anguste impress marginati, lente accrescentes, supreme 2-3 laevigati, caeteri striis incrementi obliquis aliisque spiralibus tenuibus sculpti, ultimus acute et subcompresse carinatus, inferne haud spiraliter striatus; aperture oblique, utrinque acuta; peristoma roseo-albidum, margine basali peculiariter tortuoso et incrassato.”
Trochonania bongaoensis – “Diam. maj. 13½ millim., min 12½; alt. 7.” (E. A. Smith, 1894)
Type locality – “Bongao” (E. A. Smith, 1894)
Other localities – “Sibutu” (E. A. Smith, 1894)