Original Description of Tessarolax japonicus by Yabe and Nagao, 1928
- "Shell fusiform; spire nearly as high as aperture, and incrusted by a deposit, so as to obliterate the sutures as well as the ornamentations. Whorls of spire about 6, each bearing a prominent spiral carina lying a little below the middle; flattened above and concave below the carina. Upper part of spire thickly incrusted and with a varix-like process, which is flattened on both sides and lies on the line opposite to the outer lip. Body whorl inflated, ornamented with four spiral carinae, two prominent and two narrower; angulated along the two prominent carinae, which diverge near the aperture; one of the narrower carinae situated between the prominent ones, and the other in the upper part of the base. Aperture broad above and contracted below; anterior canal lost but probably elongated, and the posterior one narrow, running beside the spire for the most part; columella incrusted, without folds; outer lip expanded showing a tendency of the two prominent carinae of the body whorl to be prolonged into two long spines."
Locus typicus: The upper course of the Ikushunbets and the ShiyŻbari, a tributary of the YŻbari-gawa, Province of Ishikari, Japan
Stratum typicum: Cretaceous
Specimens from private collections
Tessarolax japonicus Yabe and Nagao, 1928; Santonian, Cretaceous; Nakafutama-Zawa, Haboro-Cho, Tomamaegun, Hokkaido, Japan; Coll. Ulrich Wieneke