- This cladogram is a semistrict consensus of 1601 equally parsimonious trees found from the following data matrix (see Smith, A. B. 2004. Phylogeny and Systematics of holasteroid echinoids and their migration into the deep-sea. Palaeontology 47, 1-28).
-
- Character descriptions:
- 1. Frontal groove aboral to ambitus: absent (0); shallow indentation at ambitus, weakly defined aborally (1); deep groove on aboral surface, with lateral carina (2).
2. Frontal groove on oral surface: absent (0); present as shallow, poorly-defined depression (1); distinct channel leading to the peristome (2).
3. Posterior ocular plates: disjunct from remainder of apical disc (0); only one of the posterior ocular plates in contact with the posterior genital plates (1); both posterior ocular plates in firm contact with the posterior genital plates (2).
4. Anterior genital plates: separate (0); reduced to a single plate by loss or fusion (1)
5. Hydropore openings: confined to genital plate 2 (0); scattered over all anterior ocular and genital plates (1).
6. Number of gonopores (genital plates only): 4, one to each genital plate (0); 3 (no gonopore in genital plate 2) (1); 2 (no gonopores in posterior genital plates) (2).
7. Gonopores in ocular plates II and IV: no (0); yes, single (1); yes, multiple (2).
8. Position of apical disc: subcentral (0); closer than 20% test length to anterior (1).
9. Labral plate followed by a single plate posteriorly; no (0); yes (1).
10. First sternal plate largest (plastron meridosternous); no (0); yes (1).
11. Sternal plates 5.a.2, 5.b.3 uniserial (plastron metasterrnous); no (0); yes (1).
12. Sternal plates 5.a.2 to 5.a.3 forming a straight line and effectively symmetric; no (0); yes (1).
13. Episternals (5.a.2, 5.b.3) effectively paired and opposite, with suture to rear almost straight (less than 10% offset relative to plate height) (plastron orthosternous): no (0); yes (1).
14. Plates forming rear of plastron: biserial - 4a/5b or greater (0); paired post-episternals (1) paired episternals (2).
15. Rostral plate: absent (0); present (1).
16. Plastron disjunct: no (0); yes (1).
17. Anterior interambulacral plating: amphiplacous (0); meridoplacous (1).
18. Lateral interambulacral plating: amphiplacous (0); meridoplacous (1).
19. Lateral interambulacra disjunct adorally; no (0); yes (1).
20. Plate (numbered from the peristome) that lies adjacent to rear of labral plate in ambulacrum I: 1 (1); 2 (2); 3 (3).
21. Plate (numbered from the peristome) at rear suture of plastron plate 5.b.3 (left episternal in oral view) in ambulacrum I: 6 or 7 (0); 5(2); 4 (3).
22. Aboral ambulacral plates: narrow and crowded (0); large and hexagonal - approximately the same height as interambulacral plates (1).
23. Aboral ambulacral pores: single and rudimentary (0); double, with the two columns equal (1); double with a strong inequality in the size of pore-pairs in the anterior and posterior columns (2).
24. Aboral pores in frontal ambulacrum well developed and identical to those in paired ambulacra: no (0); yes (1).
25. Posterior ambulacra strongly flexed on aboral surface: no (0); yes (1).
26. Labral plate curves out to form a prominent lip: no (0); yes (1).
27. Peristome orientation: approximately horizontal or gently inclined to lower surface (0); steeply inclined or vertical (1).
28. Periproct opening framed on oral side by interambulacral plates 5.a.4/5.b.5 (0); 5.a.5/5.b.6 (1); 5.a.6/5.b.7 or above (2).
29. Periproct in adult: supramarginal, with distinct subanal shelf (0); marginal, on vertically truncate face (1); inframarginal (2); on oral surface (3).
30. Subanal fasciole: absent (0); present, crossing plates 5.a.2/5.b.3 on its adoral side (1); present crossing plates 5.b.4/5 and 5.a.4 on its adoral side (2).
31. Subanal fasciole on periproctal side passes over: plates 5.a.5/5.b.6 (1); plates 5.a.4/5.b.5 (2).
32. Marginal fasciole: absent (0); present around posterior only (1) present around entire test margin (2).
33. Beneath the periproct the marginal fasciole passes over: plates 5.a.5/5.b.6 (1); 5.a.4/5.b.5 (2).
34. Tuberculation style: no primary tubercles (0); primary tubercles present along anterior groove and adapical zone only (1); primary tubercles scattered over aboral interambulacral plates (2); primary tubercles confined to supra-ambital band (3).
|
