Key: Step 301. Pneumoderma, -dermopsis etc.

Schizobrachium
polycotylum

Schizobrachium polycotylum

Spongiobranchaea
intermedia

Spongiobranchaea intermedia

Pneumoderma

Step 302. Pneumoderma atlanticum

Pneumodermopsis

Step 304. Pneumodermopsis

Spongiobranchaea australis

Spongiobranchaea australis

Platybrachium antarcticum

Platybrachium antarcticum
Decision path