| Origin of specimens examined |
Seychelles, Japan, New Cale- |
Mauritius, Indonesia, Australia, |
|
donia, Cook Islands, Samoa, Fiji |
New Caledonia, Fiji, Philippines |
| Test colour |
black |
black |
| Test shape |
hemispherical |
hemispherical |
| Test distinctions |
ambulacra slightly raised aborally |
ambulacra slightly raised aborally |
| Iridophore pattern (interambulacra) |
blue lines (bold) |
lines of blue spots |
| Iridophore pattern (apical system) |
blue ring (bold) |
no apical ring |
| Iridophore pattern (genital plate) |
blue arch (bold) |
blue spot of iridophores |
| Mean horizontal test diameter (SD) |
68 mm (4.2 mm) |
76 mm (3.7 mm) |
| Mean vertical test diameter (SD) |
38 mm (2.1 mm) |
40 mm (2.9 mm) |
| Maximum horizontal test diameter observed |
78 mm |
84 mm |
| Maximum vertical test diameter observed |
44 mm |
48 mm |
| Markings on test (median area of |
white spot marking (typically |
white spot marking (day and |
| interambulacra) |
night only) |
night) |
| Markings on naked test (median area of |
geographic variation, white spot/ |
white line and spot markings |
| interambulacra) |
no spot |
|
| Markings on naked test (genital plate) |
distinct arched depression |
green/blue spot marking |
|
|
(typically) |
| Number of tubercles on genital plate |
1-3 tubercles |
3-5 tubercles |
| Height to width (at widest point) ratio of |
0.69:1 |
0.72:1 |
| genital plate |
| Diameter of gonopore (% of genital plate |
28% |
25% |
| height) |
| Form of apical system |
hemicyclic |
hemicyclic |
| Form of periproct (distinguishing features) |
small black, no ring or platelets |
small black, orange ring, no |
|
|
platelets |
| Apical system (% of horizontal test diameter) |
22-28% |
22-28% |
| Periproct (% of horizontal test diameter) |
13-18% |
12-20% |
| Peristome (% of horizontal test diameter) |
42-50% |
40-50% |
| Ambulacra % of interambulacra (at ambitus) |
28-30% |
25-30% |
| Tubercle structure |
perforate and crenulate |
perforate and crenulate |
| Number of median series of tubercles on |
variable (1 or 2) |
variable (1 or 2) |
| interambulacra |
| Rudimentary tube feet present on the |
no |
no |
| peristome |
| Buccal tube feet present |
5 pairs |
5 pairs |
| Spines present on the buccal plates |
no |
no |
| Number of specimens examined |
200 |
200 |