TABLE 1. Occurrence of Arachnostega in the Aluvere Quarry (Sandbian).
|
Taxa |
Total number of specimens |
Number of specimens with Arachnostega |
|
Gastropoda |
506 |
60 (12%) |
|
Bivalvia |
106 |
28 (26%) |
|
Cephalopoda |
70 |
13 (19%) |
|
Hyolitha |
16 |
3 (19%) |
TABLE 2. Distribution of Arachnostega in gastropods from the Ordovician (global stages) of Estonia.
|
Stage |
Total gastropods |
Gastropods with Arachnostega |
|
Katian |
282 |
8 (3%) |
|
Sandbian |
765 |
85 (11%) |
|
Darriwilian |
93 |
16 (17%) |
TABLE 3. Arachnostega diameter in gastropods in the Ordovician of Estonia.
|
Stage |
Arachnostega burrows diameter in gastropods |
|
Katian |
0.35-1.14 mm (N=7, Mean 0.55, sd 0.28) |
|
Sandbian |
0.22-1.00 mm (N=37, Mean 0.57, sd 0.23) |
|
Darriwilian |
0.24-1.37 mm (N=15, Mean 0.76, sd 0.34) |
