Panacanthocystida Shishkin et Zlatogursky, 2018

Diagnosis: Centrohelids usually covered with siliceous scales or with organic spicules: scale-bearing species with both inner plate-scales and outer spine-scales of other morphology or only plate-scales with a hollow inrolled margin; outer scales may be of different types based on archetype of plate-scale morphology or radially symmetrical, present in one of two forms: funnel-shaped, or needle-like with a radially symmetrical base.

Acanthocystida
Panacanthocystids usually covered with siliceous scales or with organic spicules: scale-bearing species with both plate and spine scales or only plate scales with a hollow inrolled margin; outer scales radially symmetrical, present in one of two forms: funnel-shaped, or needle-like with a radially symmetrical base.

Marophryina
Panacanthocystids typically lacking silica scales but covered with numerous thin, pointed organic spicules tapering towards acute apices.

• • • • Marophryidae
        
        

Chalarothoracina
Panacanthocystids usually covered with siliceous scales or with organic spicules: scale-bearing species with both plate- and spine-scales or only plate-scales with a hollow inrolled margin; outer scales radially symmetrical, present in one of two forms: funnel-shaped, or needle-like with a radially symmetrical base.

• • • • Raphidocystidae
      • Acanthocystidae

Chthonida

Panacanthocystids typically covered with two types of siliceous scales: scales of inner layer are flattened, simple in structure, usually ornamented with axial rib, outer scales may be of different types but more similar to plate-scales than to spine-scales.

Yogsothothina
Diagnosis as for Chthonida above.

• • • • Yogsothothidae