Caulostrepsis Clarke, 1908

Macroboring; substrate calcareous; tracemaker invertebrate

Category of architectural design: 2.61. U-shaped borings.

Unbranched, U-shaped

Diagnosis: Borings with one entrance or embedment structure, pouch-shaped, created by a U-shaped gallery. More complex structures can result from multiple lobes of similar structure. The individual limbs of the gallery can be clearly visible along their total length, they can be connected by the vane, or they can be fused in an oval or flattened pouch shape without the vane. The distal end has at least double the width of the apertural end. The cross-section is variably flat-oval, elliptical, constricted, or dumbbell-shaped. Symmetrical, radially organized grooves or deep pits can be developed near the aperture n some cases (normally 2 to 4 in number). The aperture may have similar form to the proximal cross-section or it may be modified by the development of superficial branches, grooves, and/or holes (Bromley and d’Alessandro, 1983).