Synoptic Keys to the Genera of Ophiuroidea
Family Euryalidae Gray, 1840 — (Syn. Trichasteridae sensu Mortensen, 1933)
Family
Euryalidae
Gray, 1840
(Syn. Trichasteridae sensu Mortensen, 1933)
1 (6) |
Arms simple. |
2 (5) |
Arms with a prominent dorso-lateral ridge of spines or granules on either side: arm-spines short, of equal size. |
3 (4) |
Dorso-lateral ridges carrying numerous, very prominent tubercles: additional interradial plates lying distal to the adoral shields. . . . Asterostegus Mortensen, 1933. *tuberculatus Mrtsn., 1933. S. Africa. 200 fms. |
4 (3) |
Dorso-lateral ridges with scattered tubercles or spines: no additional interradial plates distal to the adoral shields, interredius naked ventrally. . . . Astroceras Lyman, 1879. For a review of this genus see Mortensen, 1933a. *pergamena Lyman, 1879. Japan. 100 fms. |
5 (2) |
Arms rounded above, without dorsolateral ridges: inner arm-spine usually longer than the outer. . . . Asteromorpha Lütken, 1869. Synonym Ophiogelas Koehler. *Asteroschema rousseaui Michelin, 1862. Indian O. 100 fms. |
6 (1) |
Arms forking several times: arm-spines short, both of equal size. |
7 (10) |
More than 18 arm-joints occurring before the first fork. page 11 |
10 (7) |
Less than 10 arm-joints before the first fork: arms forking repeatedly over most of their length: gonads entering the arms. . . . Euryale Oken, 1815. Euryale is usually attributed to Lamarck, 1816: however, Oken's usage appears to have priority. The current employment of Euryale stems from Lyman, 1882; previously it was an absolute synonym of Gorgonocephalus: for discussion, see Verrill, 1899. *asperum Lmk., 1816. Indonesia. Littoral. |
8 (9) |
Arms with dorso-lateral ridges, often set with spines or granules: lateral plates widely separated on ventral surface of arm: arms branching only in their distal halves: gonads entering arms. . . . Trichaster Agassiz, 1836. *Euryale palmiferum Lmk., 1816. Indian O. 100 fms. |
9 (8) |
Arms symmetrically rounded above, without dorso-lateral ridges: lateral plates meeting on ventral midline of arm: gonads confined to disc. . . . Sthenocephalus Koehler, 1898. *indicus Koehler, 1898. Indonesia. 30 fms. |