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Synoptic Keys to the Genera of Ophiuroidea

Family Hemieuryalidae Verrill, 1899

Family Hemieuryalidae Verrill, 1899

1 (8)

Dorsal arm-plates partly or completely subdivided into smaller plates: 3 short, flat arm-spines and 1 short, flat tentacle-scale (Subfamily Hemieuryalinae Matsumoto, 1915).

2 (3)

Dorsal arm-plates completely fragmented, forming a mosaic. . . . Hemieuryale von Martens, 1867.

*pustulata v. Mart., 1867. West Indies. 100 fms.

3 (2)

Dorsal arm-plates subdivided into a larger medium portion, plus some other plates or platelets.

4 (7)

A large supplementary plate on either side of each dorsal plate.

5 (6)

One genital cleft in each interradius. . . . Quironia A. H. Clark, 1934.

*johnsoni A. H. C., 1934. West Indies. Littoral.

6 (5)

Two genital clefts in each interredius. . . . Sigsbeia Lyman, 1878.

*murrhina Lyman, 1878. Cuba. 175 fms.

7 (4)

Dorsal arm-plates of adjacent segments separated by an intervening transverse row of small platelets. . . . Ophioplus Verrill, 1899.

*Hemieuryale tuberculosa Lyman, 1883. West Indies. 100 fms.

8 (1)

Dorsal arm-plates entire; without supplementary plates: 5–8 conical armspines: no tentacle-scale, but lowest arm-spine may serve as one (Subfamily Ophiochondrinae Verrill, 1899, emend. Matsu. 1915).

9 (10)

Disc-plates covered by a thick granulated skin. . . . Ophiochondrus Lyman, 1869.

(Mortensen, 1927, 1936, has referred this genus to the Ophiacanthidae, without discussion.)

*convolutus Lyman, 1869. Cuba. 270 fms.

10 (9)

Disc-plates naked.

11 (18)

Ventral arm-plates developed normally throughout arm.

12 (13)

Paired interradial sacs between the oral shields and radial shields. . . . Ophioleila A. H. Clark, 1949.

*elegans A. H. C., 1949. Hawaii. 600 fms.

13 (12)

Interradii of normal form, without interradial sacs.

14 (17)

Disc circular in outline: uppermost arm-spines longer than others.

15 (16)

Genital clefts pore-like, placed beside the small oral shield. Ventral interradius covered by several polygonal plates. Primary plates inconspicuous. . . . Amphigyptis Nielsen, 1933.

*perplexa Niel., 1933. Panama. Littoral.

16 (15)

Genital clefts elongate. Single large plate covers the ventral interradius. Primary plates conspicuous. . . . Ophiocyclus H. L. Clark, 1939.

*Ophioceramis clausa Lyman, 1878. Kermadec Is. 600 fms.

(It seems doubtful whether this genus is distinct from Amphigyptis, of which it may be a developmental stage.)

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17 (14)

Disc distinctly 5-lobed owing to the larger radial shields and contracted interradii. . . . Ophiomoeris Koehler, 1904.

Syn: Ophiurases H. L. Clark, 1911.

*spinosa Koehler, 1904. Kei Is. 160 fms.

18 (11)

Ventral arm-plates beyond the three basal arm-segments either lacking or fragmented.

19 (20)

Ventral arm-plates lacking beyond the third basal segment, and replaced by a ventral furrow. . . . Ophioholcus H. L. Clark, 1915.

*Sigsbeia sexradiata Koehler, 1914. West Indies. 350 fms.

20 (19)

Ventral arm-plates beyond the third basal segment are fragmented into small platelets. . . . Ophiogyptis Koehler, 1905.

*nodosa K., 1905. Indonesia. 50 fms.