Key for the species identification of the Order Aspidochirotida known from northeast Brazil:

1 Gonads in two tufts, one on each side of dorsal mesentery. Tables and C-shaped ossicles present (Family Stichopodidae)...................................................................................... Isostichopus badionotus

- Gonads in a single tuft, on left side of dorsal mesentery. Tables present, usually accompanied by buttons, plates or rods, but there are no C-shaped ossicles (Family Holothuriidae)........................................................ 2

2 Ossicles of the body wall are rosette-like elements........................................... Actinopyga agassizii

- Ossicles of the body wall of different forms than rosettes (Genus Holothuria)..................................... 3

3 Tables with disc margin knobbed............................................. Holothuria (Cystipus) pseudofossor

- Tables with disc margin smooth or spinous................................................................. 4

4 Tables with reduced disc............................................... Holothuria (Semperothuria) surinamensis

- Tables with well-developed disc.......................................................................... 5

5 Tables accompanied by irregular buttons (indented or knobbed) or regular buttons (knobbed)......................... 6

- Tables accompanied by smooth buttons or delicate perforated plates............................................. 8

6 Buttons irregular or complex, not knobbed on surface......................................................... 7

- Buttons regular, knobbed on surface........................................... Holothuria (Holothuria) dakarensis

7 Buttons complex, similar to fenestrated plates, with parallel perforations. Tables large in tube feet............................................................................................... Holothuria (Theelothuria) princeps

- Buttons irregular, with perforations usually alternating. Large tables absent in tube feet.... Holothuria (Platyperona) parvula

8 Tables small, accompanied by smooth plates, with 2–4 central perforations and a few smaller perforations surrounding these, without buttons............................................................... Holothuria (Halodeima) grisea

- Tables with semicircular discs with 4–8 marginal perforations and a small spire, small and smooth buttons........................................................................................ Holothuria (Thymiosycia) arenicola