Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

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.