Synoptic Keys to the Genera of Ophiuroidea
Family Ophiothricidae Ljungman, 1866
Family Ophiothricidae Ljungman, 1866
1 (26) |
Radial shields low, without a raised crest. |
2 (3) |
Disc covered above and below by naked skin through which only the distal ends of the radial shields project; no tentacle scales or, at most, scales present only on basal arm-joints. . . . Ophiogymna Ljungman, 1866. Syn.: Ophiocampsis Duncan, 1887 (see Koehler 1922a, p. 284). *elegans Ljung., 1866. Indonesia. Littoral. |
3 (2) |
Disc not covered by naked skin. page 24 |
4 (9) |
Upper surface of disc bearing granules. |
5 (8) |
Lower surface of disc covered by skin. |
6 (7) |
Dorsal surface of arms bearing granules, tubercles or coarse irregular grains, which more or less obscure the plates; dorsal arm-plates reduced in size. . . . Ophiothela Verrill, 1867. Syn.: Ophioteresis Bell, 1892 (juvenile stage). *mirabilis Verrill, 1867. Panama. Littoral. |
7 (6) |
Entire dorsal surface of disc and arms densely coated with uniform granules which completely obscure all plates; tentacles issue from side of arms. . . . Ophiopsammium Lyman, 1874. *semperi Lyman, 1874. Philippine Is. Littoral. |
8 (5) |
Lower surface of disc covered by fine scales. . . . Ophiocnemis Mueller & Troschel, 1842. *Ophiura marmorata Lmk., 1816. Indian Ocean. Littoral. |
9 (4) |
Upper and lower surfaces of disc covered by plates. |
10 (11) |
Disc covered by primary plates and radial shields; two arm-spines. . . . Ophiophthirius Doederlein, 1898. *actinometrae Doed., 1898. Torres Strait. Littoral. The type (and only known) species was epizoic on a comatulid, and may be a juvenile stage of some other genus. |
11 (10) |
Disc covered by numerous other plates, besides the primaries; four or more arm-spines. |
12 (19) |
Radial shields large and conspicuous. |
13 (16) |
Disc plates bear spines or thorns. |
14 (15) |
Arm-spines of the proximal arm-joints united by a membranous web into vertical fin-like fans. . . . Ophiopteron Ludwig, 1888. *elegans Ludwig, 1888. Amboina. Littoral. Mortensen (1932) has shown that some spp. of Ophiothrix pass through an "Ophiopteron" stage. |
15 (14) |
Arm-spines of all arm-joints free, not united by webs. . . . Macrophiothrix H. L. Clark, 1938. Syn.: Placophiothrix H. L. Clark, 1938. *Ophiura longipeda Lmk., 1816. Indo-Pacific. Littoral. |
16 (13) |
Disc plates without spines or thorns. |
17 (18) |
Dorsal arm-plates short and wide; arm-spines smooth and opaque. . . . Ophiomaza Lyman, 1871. Syn.: Lütkenia Brock, 1888. *cacaotica Lyman, 1871. Indo-West-Pacific. Littoral. Species of this genus may occur as epizoic forms on various comatulids. |
18 (17) |
Dorsal arm-plates not short and wide; arm-spines thorny. . . . Ophiotrichoides Ludwig, 1882. *lymani Ludwig, 1882. Tropical W. Atlantic. Littoral. The genus is strongly represented in the Indo-Pacific, and at least one species has an "Ophiopteron" stage; see H. L. Clark (1946, p. 230). |
19 (12) |
Radial shields small or partly concealed by spinules. |
20 (21) |
Dorsal arm-plates bearing minute spinelets. . . . Amphiophiothrix H. L. Clark, 1946. *Ophiothrix demessa Lyman, 1861. Tropical Indo-Pacific. Littoral. |
21 (20) |
Dorsal arm-plates smooth. |
22 (23) |
Spines or thorns on disc plates; tentacle-scales present. . . . Ophiothrix Mueller & Troschel, 1840. page 25Syn.: Ophionyx M. & T., 1840. *Asterias pentaphylla Pennant, 1777. Britain. Littoral. |
23 (22) |
Disc plates with no spines or thorns. |
24 (25) |
Arm-spines not longer than width of arm; radial shields contiguous along their whole length; androphorous, epizoic on Diadema and Toxopneustes; distal arm-spines hooked. . . . Ophiosphaera Brock, 1888. *insignis Brock, 1888. Amboina. Littoral. |
25 (24) |
Arm-spines long and slender, up to four times as long as width of arm; radial shields scarcely contiguous. . . . Lissophiothrix H. L. Clark, 1938. *delicata H. L. Clark, 1938. Tropical Australia. Littoral. |
26 (1) |
Radial shields each carry a raised vertical crest. Disc naked above and below, or with only a few small scattered scales imbedded in skin. |
27 (28) |
Some proximal dorsal arm-plates carry a high median keel; beyond disc ventral arm-plates become rounded and widely separated. . . . Ophiolophus Marktanner-Turneretscher, 1887. *novarae M-T, 1887. Nicobar Is. Littoral. |
28 (27) |
Dorsal arm-plates without keels. |
29 (30) |
Disc and arms minutely granulated. . . . Gymnolophus Brock, 1888. *Ophiothela holdsworthii E. A. Smith, 1878. Ceylon. |
30 (29) |
Disc and arms naked. . . . Ophioaethiops Brock, 1888. Syn.: Ophiohelix Koehler, 1895. *unicolor Brock, 1888. Amboina. Littoral. |