The siphogonuchitid
scleritome consists of two main kinds of sclerites (lopochitid, originally referred to
Lopochites, and paleosulcachitid, originally referred to
Siphogonuchites), as well as dabashanitid arrays of fused sclerites (originally referred to
Dabashanites) and a maikhanellid (originally referred to
Maikhanella) shell. Siphogonuchitid sclerites are hollow and bear prominent ridges.
Lopochitid sclerites are elongate, narrow,
helically twisted by up to 90 degrees, and gently bent
longitudinally, while
palaeosulcachitid sclerites are flattened and curved in one plane.
Dabashanitid sclerites are composed of multiple sclerites sharing a common base. They are likely derived from the fusion of paleosulcachitid sclerites and may serve as central branched sclerites of the siphogonuchitid
scleritome. Besides these basic types of sclerites, there are several other kinds that are much less common. The
maikhanellid shell is
patelliform and bears a distinct pattern of scales. These scales are embedded siphogonuchitid sclerites.
Calvapilosa is the sole siphogonuchitid not known from isolated shells or sclerites, and bears a single anterior shell, a dorsoventrally flattened body, and a
dorsal mantle coated in sclerites. ==References==