Artificial key to the species of Trimuricea

1. All sclerites faintly yellow.................................................................... T. flava n. sp.

- All sclerites colourless................................................................................. 2

2. Colony without anastomoses; unilateral spinose spindles up to 1 mm long present.............. T. africana Gordon, 1926

- Colony with numerous anastomoses....................................................................... 3

3. Coenenchymal spindles and thornscales shorter than 0.5 mm long, with simple tubercles only......................... 4

- Coenenchymal spindles and thornscales longer than 0.5 mm long, with complex and simple tubercles................... 7

4. Thornscales with smooth, short thorn up to 0.10 mm long; spindles with one or more thorny end....... T. omanensis n. sp.

- Thornscales with longer thorn........................................................................... 5

5. Thornscales and polyp triradiates with smooth, blunt ended thorn and upper ray............. T. caledonica Grasshoff, 1999

- Thornscales and polyp triradiate without smooth, blunt upper ray............................................... 6

6. Thornscales with simple tubercles and arms that do not branch; slender coenenchymal spindles up to 0.5 mm long................................................................................................. T. bicolor n. sp.

- Thornscales with simple tubercles and complex base; slender coenenchymal spindles up to 0.35 mm long................................................................................................ T. inermis (Nutting, 1910)

7. Thornscales with one long, smooth, thorn and simple base.................... T. reticulata (Thomson & Simpson, 1909)

- Thornscales with shorter echinulate or tuberculate thorn, and complex base........................................ 8

8. Thornscales and coenenchymal spindles with complex, dense tubercles, thornspindles and spindles that resemble unilaterally spinose spindles present................................................................ T. tuberculosa n. sp.

- No thornspindles and spindles that resemble unilaterally spinose spindles present................................... 9

9. Most thornscales with a single thorn........................................................... T. persica n. sp.

- Most thornscales with several thorns..................................................................... 10

10. Spindles with one blunt end present................................................. T. merguiensis Gordon, 1926

- Spindles having similarly shaped ends......................................................... T. spinosa n. sp.