Dendrochirotida

Pawson, David L., Pawson, Doris J. & King, Rachael A., 2010, A taxonomic guide to the Echinodermata of the South Atlantic Bight, USA: 1. Sea cucumbers (Echinodermata: Holothuroidea), Zootaxa 2449, pp. 1-48 : 11-12

Key to members of the Order Dendrochirotida known from the South Atlantic Bight

1. Body limpet-like, partially covered by conspicuous overlapping plates (Family Psolidae ) ........................................ 2

- Body without a partial test; ossicles usually small, inconspicuous .............................................................................. 4

2. Five distinct oral valves present.................................................................................................................................... 3

- Not five distinct oral valves .................................................................................................................... Psolus fabricii

3. Dorsal plates with small knobs (tuberculated). Plates in sole with 10 or more perforations.......................................... ..................................................................................................................................................... Psolus t. tuberculosus

- Dorsal plates not tuberculated. Plates in sole with about four perforations ..................................... Psolus operculatus

4. Calcareous ring simple, lacking posterior processes. (Family Cucumariidae )............................................................. 5

- Calcareous ring with paired or unpaired posterior processes ..................................................................................... 11

5. Ossicles in body wall include tables. ................................................................................. Duasmodactyla seguroensis

- Ossicles in body wall not including tables.................................................................................................................... 6

6. Tube feet restricted to radii, at least ventrally, mostly absent from interradii .............................................................. 7

- Tube feet present in radii and interradii........................................................................................................................ 9

7. Ossicles irregular four-holed plates with low knobs and not including cups ......................... Paracolochirus mysticus

- Ossicles include cups and buttons. ............................................................................................................................... 8

8. Cups irregular, hollow, like reticulated eggs. Buttons of one type, with ten knobs. .............................. Aslia pygmaea

- Cups deep, concavity defined by four spokes. Buttons of two types: heavier small-holed and delicate large-holed .... .......................................................................................................................................................... Aslia surinamensis

9. Tube feet most numerous along radii. Perforated plates in body wall. Cups flattened, shallow, margin solid, with 7–9 teeth. ................................................................................................................................................ Thyonella gemmata

- Tube feet uniformly scattered over body. No perforated plates in body wall............................................................. 10

10. Cups deep with narrow opening; margin fringed with numerous, irregular, small teeth on both inner and outer sides ......................................................................................................................................................... Euthyonacta solida

- Cups shallow with wide opening; with 7–10 blunt teeth forming margin ....................................... Thyonella pervicax

11. Posterior processes of calcareous ring simple, entire ................................................................................................. 12

- Posterior processes of calcareous ring complex, composed of a mosaic of minute pieces. ....................................... 14

12. Ossicles knobbed buttons. Tube feet contain elongate tables .......................................................... Pseudothyone belli

- Ossicles tables. Buttons absent. .................................................................................................................................. 13

13. Tables oblong to oval, with two-pillared spires. .............................................................................. Euthyonidiella trita

- Tables squarish, with four-pillared spires. .................................................................................. Sclerodactyla briareus

14. Tube feet restricted to the radii. ................................................................................................ Pentamera pulcherrima

- Tube feet scattered on body wall. ............................................................................................................................... 15

15. With 10 tentacles......................................................................................................................................................... 16

- With 20 tentacles. Ossicles tables with scalloped margins and 4–8 perforations. Table spires reduced to form four bluntly pointed projections. ............................................................................... Phyllophorus (Urodemella) arenicola

16. Ossicles tables with oval disc, four perforations, and thick margins.......................................................................... 17

- Ossicles tables with thin margins, irregular disc outlines, and few to numerous perforations................................... 18

17. Spires of tables terminating in several short teeth .......................................................................... Thyone pseudofusus

- Spires of tables terminating in a single blunt spine ......................................................................... Thyone crassidisca

18. Tables with 20–30 holes. Tables in tube feet with short, non-tapering spires ................................................................ .......................................................................................................................................................... Havelockia scabra

- Tables with 4–8 or 8–18 holes. Tables in tube feet with longer, tapering spires .......................................................... 9

19. Tables with 4–8 holes. Tables in tube feet with abruptly tapering spires ............................................. Thyone pawsoni

- Tables with 8–18 holes. Tables in tube feet with gently tapering spires ....................................... Thyone deichmannae