| Home> Miocene>

List species

Heliosoma watkinsi Keany, 1979

Description - Add description

Cortical shell thin-walled with large irregular pores of different size and shape, generally three to eight times as broad as the bars. Medullary shell generally one-fourth as large, with small regular hexagonal pores. Two shells connected by 30 to 50 irregularly disposed, circular, radial beams. Beams, generally not prolonged beyond cortical shell, have small irregularly spaced spines on surfaces. Projecting from surface of cortical shell, numerous secondary spines, simple and conical.
Measurements: based on 10 specimens from samples: E34-19:158cm and 238cm; length of secondary spines, 50-56µm; length of connecting beams, 122-130µm; maximum diameter of cortical shell, 345-360µm; maximum diameter of medullary shell, 76-96µm.
This species is characterized by the rough, irregular surface of the cortical shell, and is often found with the secondary spines broken off. It differs from Heliosoma hastatum (Haeckel) in having irregularly spaced spines on the radial beams and simple conical spines projecting from the surface of the cortical shell rather than three-sided pyramidal, spear-shaped spines.
Keany 1979











Discussion / Comments


Web links