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Synoptic Keys to the Genera of Ophiuroidea

Family Ophiactidae Matsumoto, 1915

page 23

Family Ophiactidae Matsumoto, 1915

1 (8)

Disc scaled above and below.

2 (3)

A circle of small platelets surrounds each dorsal arm-plate: granules or spinules on disc, but primary plates naked and distinct: lower arm-spine hooked on distal part of arm. . . . Ophiopholis Mueller & Troschel, 1840.

*Ophiolepis scolopendrica M. & T. = Asterias aculeatus Retzius, 1783.

N. Hemisphere. Littoral and deep water.

3 (2)

Dorsal arm-plates contiguous, not surrounded by platelets.

4 (7)

No spines on disc: not fissiparous: five arms.

5 (6)

Radial shields united in pairs: three oral papillae, of which the outermost is enlarged (but not operculiform), all three papillae partly fused together: genital clefts present: the male dwarfed and carried on the ventral surface of the female. . . . Ophiodaphne Koehler, 1931.

*materna Koehler, 1931. Indonesia. 100 fms.

6 (5)

Radial shields separated: not androphorous. No genital clefts: two or three oral papillae: one tentacle-scale. . . . Ophiopus Ljungman, 1866.

Syn.: Ophiaregma Sars, 1872.

*arcticus Ljungman, 1866. Arctic. 600 fms.

7 (4)

Spines present on disc, though not so numerous as to conceal the coarse scales: often with six or seven arms, and reproducing by transverse fission of the disc: one or two oral papillae. . . . Ophiactis Lütken, 1856.

Syn.: Amphiactis Matsumoto, 1915 (non Verrill, 1869).

*krebsii Lütk. = Ophiolepis savignyi M. & T., 1842. Tropics.

8 (1)

Disc scaled above but naked below: a single (outer) oral papilla: adoral shields all in contact, thus forming a continuous ring around the mouth: radial shields united in pairs. . . . Hemipholis Lyman, 1865.

*Ophiura elongata Say, 1825. Caribbean. Littoral.