Craterostigmus is distinguished from all other centipedes by:
Craterostigmus tasmanianus, showing the pair of 'can opener' tooth plates on the maxillipede coxosternite. These are the same in C. crabilli, which has 5–8 teeth on each plate. © Sue Lindsay, Australian Museum
Craterostigmus crabilli in dorsal view, showing the basal parts of the 15th leg pair. The elongate structure projecting behind the ultimate leg-bearing segment is the anal capsule. This specimen comes from Dunedin, South Island.
Craterostigmus crabilli in ventral view, showing the anal capsule opened to reveal 8 fields (4 on each side) of pores that are openings of the anal glands.
Enlargement of the openings of the anal glands in Craterostigmus crabilli. The depression is the central part of the anal capsule is the anus (Rosenberg et al, 2006).
It is difficult to distinguish Craterostigmus crabilli from its closest relative Craterostigmus tasmanianus using morphological characteristics alone.
The two species can be separated based on molecular characteristics, or using a combination of external and internal anatomical characters:
Plate at the base of the maxillipedes, composed of the fused coxa (the basal leg segment) and sternum.
Same number of body segments at different stages of lifecycle.
A modified pair of legs that functions as an external reproductive organ.
Lip that originates at the border of the mouth in arthropod development.
Tubes used for excretion.
The outer, segmented part of the first pair of mouth appendages immediately behind the mandibles (jaws).
Modified anterior pair of trunk legs that are a functional part of the head.
Hardened plate like body parts.
Plates on ventral surface.
Plates along the back.
Second segment of a leg, between the coxa and the prefemur.