Brachyura larvae
Key to recognize zoeal larvae of major decapod groups

1a. Telson cylindrical in cross section-> 2.
1b.Telson flattened-> 3.
2a.Telson with two blunt rami: protozoea of Dendrobranchiata (Penaeoidea, Sergestoidea).
2b.Telson not produced into blunt rami-> 4.
3a.Telson furcated: zoea of Brachyura (Brachyura, Portunidae).
3b.Telson not furcated-> 5.
4a.Body extremely flattened dorsoventrally; forebody pear-shaped, wider than long or as long as wide; maxilliped 3 with or without exopod; abdomen one tenth to one fourth of total length: Phyllosoma of Scyllaridae and Palinuridae (Palinura, Scyllaridae).
4b.Body not extremely flattened; eyes rarely covered by carapace; at least two pairs of functional thoracopods with chelae; antennal exopod unsegmented or segmented at tip only; abdomen one third of total length (excluding rostrum): Eryoneicus of Polychelidae (Palinura, Polychelidae); zoea of Nephropoidea (Astacura, Nephropoidea).
5a.Telson spatula-like, with first marginal process never as a spine; carapace without dorsal and lateral spines; antennal scale segmented: zoea of Caridea (Caridea).
5b.Telson subtriangular-> 6.
6a.Lateral margin of the telson serrate and rostral spine well developed: zoea of Stenopodidea (Stenopodidea).
6b.Lateral margin of the telson smooth-> 7.
7a.Posterior border of the telson bearing a conspicuous median spine, abdominal somites 2-6 with prominent dorsal median spine: zoea of Thalassinidea (Thalassinidea).
7b.Carapace longer than wide; telson formula 7+7, the first lateral process spinous and the second one hair-like; antennal scale more or less developed: zoea of Anomura and Dromiacea (Anomura, Diogenidae, Anomura, Hippidae, Anomura, Paguridae, Anomura, Porcellanidae, Dromia erythropus ov, Homola barbata ov, Latreillia elegans ov).