Ancistrolepis trochoideus: Height 20 mm, Width 14.5 mm

Ancistrolepis trochoideus: Shell is small, solid, rhombus, consists of 5.5-6 very convex whorls. The spire is low, the body whorl occupies 3/4 of the shell height. Sculpture consists of keel on the shoulder whorl, narrow spiral cords (6-7 on the body whorl and numerous intercalary threads. Aperture is large, wide, rhombus, white or light yellowish, occupies about 1/2 of the shell height. Siphon is slightly elongated, wide, curved to the left.
[Egorov, 1994]

-300~400m, Choshi City, Chiba Prefecture, Japan, 30.3mm., 1976/x.
Bathyancistrolepis trochoideus is a very peculiar buccinid endemic to the Pacific side of Honshu, Japan. Recent specimens are very rare, especially so in collections outside Japan; and it is better known from Pleistocene fossils frequently found in lioka Formation of Chiba Prefecture for example, around 0.7-2 million years old and currently considered to be the same species. It is a carnivorous / scavenging gastropod usually inhabiting muddy bottoms of deep water ranging from -100-1000m. Shown here is a specimen of form ovoideus, which is more bulbous with a shorter spire and fewer cords near the siphonal canal. Typical shell length around 30mm., very large specimens may exceed 40mm.

Ancistrolepis trochoideus: Northern Japan, Sagami Bay, Izu-Oshima Island, Kumano-Nada, at depth from 620 to 2050 m. Rare.