Descriptor : Type of carcass external plates (IW)
Descriptor type : categorical
External plates: Plate covering incompletely one or several perforations of a wall.
Carcass: Part of wall on intervallum side.
IW: Inner wall.
- Spines
-
Spine: Skeletal structure comprising a narrow, elongate and typically tapering process with a circular to subcircular attachment area.
NB: Spines resemble bracts.
Spines
- Bracts
-
Bract: Plate stems from lintels which incompletely covering a single pore.
Lintel: Skeletal structure separating and bounding adjacent pores. - Scales
-
Scale: Plate incompletely covering two or more adjacent pores or intersepts in the same horizontal file. They are intermediate between fused bract and annulus.
Scales
- Annuli
-
Annulus (plur. annuli): Ring-shaped (annular) plate separating horizontal rows of pores.
Annuli
Annuli
- Poretubes
-
Poretube: Structure of elongate, scooplike to tubular shape completely or almost completely covering a single pore.
NB: Poretubes resemble canals but have a bract origin.
Hierarchy
Carcass external plates: inner carcass wall (IW) | |_ Type of carcass external plates (IW) | |_ Localisation of carcass bracts (IW) {Spines , Scales , Annuli , Poretubes} | |_ Relationship between carcass annuli and tabulae (IW) {Spines , Bracts , Scales , Poretubes}