Ausich et al.—Disparid and hybocrinid crinoids from the Brechin Lagerstätte
861
zoidal; E inferradial trapezoidal, occupying ~20% of radial- basal articulation; E superradial occupying ~55% of the distal aboral cup margin. Distal facet of A and D radials supporting a lateral arm. Other aspects of radial and anal plates unknown, including verification that B arm is present. Four arms presumably present. Arms slender with aborally
convex brachials; brachials rectilinear uniserial or cuneate uniserial, higher than wide, yielding arms with zig-zag appear- ance. Main axil with nonaxillary brachials; divisions isotomous. E-ray arm unbranched; E-ray brachials higher than wide, rectilinear uniserial (Fig. 8.4). Main axils weakly developed; two axillaries present, each separated by one nonaxillary brachial. Lateral arms apparently with normal bilateral heterotomy. Primaxil arm bifurcating at least through epsilon axillary with two (proximally) or four (distally) nonaxillary brachials before each bifurcation; three divisions preserved on betaaxil arm with three and five nonaxillary brachials before each bifurcation; beta ramules not visible. Other details of arms unknown. Column homeomorphic; proxistele with very thin columnals
with wavy or straight sutures. Beneath aboral cup proxistele columnals approximately six times wider than high and wedge
shaped.Mesistele and dististele columnals three times wider than high.Holdfast an irregular, subovatemass of stereomcemented to crinoid pluricolumnal. Holdfast classified as simple, discoidal, cemented type (Fig. 8.4).
Materials.—CMCIP 366334 (3 specimens);UMMP74664 and 74665.1.
Measurements.—UMMP 74664: CrH, 30.0*; ACH, 5.0; proxi- mal, ACW, 7.0; CoH, 24.0. UMMP 74665.1: CrH, 30.0; ACH, 4.5; proximal ACW, 5.1; CoH, 19.5*.
Remarks.—See remarks under genus.
Cremacrinus inaequalis (Billings, 1859) Figure 9.4, 9.5
Figure 7. Anomalocrinus astrictus n. sp., holotype, C-ray lateral view of partial crown (note large brachials in the C-ray arm); calyx sculpture is smooth and pitting on calyx plates on this specimen is a preservational artifact (compare to Figure 5.4), UMMP 74661. Scale bar=5.0mm.
Description.—Crown without perfect bilateral symmetry, probably pendant on column. Aboral cup small, adorally-aborally com- pressed; plate sculpture coarsely pitted; sutures impressed (Fig. 8.5). Basal plates four, all in column concavity, all part of distal
margin of basal circlet. Radial circlet almost twice as wide as high, wider proximally, tapering distally (Fig. 8.5); trapezoidal and slightly indented along line between proximal edge ofAand D radial facets; ligament pit divided. A and D radial plates occupying majority of radial circlet. E-ray inferradial and superradial with narrow sutural contact; E superradial trape-
1859 Heterocrinus inaequalis Billings, p. 51, pl. 4, fig. 7a. 1868 Heterocrinus inaequalis; Shumard, p. 377. 1868 Heterocrinus inaequalis; Bigsby, p. 20. 1886 Cremacrinus inaequalis; Ulrich, p. 113. 1889 Calceocrinus inaequalis; Miller, p. 230. 1889 Castocrinus inaequalis; Ringueberg, p. 395, pl. 10, fig. 5. 1915 Cremacrinus inaequalis; Bassler, p. 289. 1943 Cremacrinus inaequalis; Bassler and Moodey, p. 376. 1946 Cremacrinus inaequalis; Wilson, p. 35, pl. 5, fig. 4. 1962 Cremacrinus inaequalis; Moore, p. 21. 1973 Cremacrinus inaequalis; Webster, p. 86. 1982 Cremacrinus inaequalis; Brower, p. 93. 1988 Cremacrinus inaequalis; Webster, p. 60.
Holotype.—GSC 1444.
Diagnosis.—Cremacrinus with smooth aboral cup sculpture; aboral cup wider than high; aboral cup plates not swollen; axil arms two; axillaries not swollen; arms slender; brachials recti- linear uniserial, wider than high; E-ray arm unbranched.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148 |
Page 149 |
Page 150 |
Page 151 |
Page 152 |
Page 153 |
Page 154 |
Page 155 |
Page 156 |
Page 157 |
Page 158 |
Page 159 |
Page 160 |
Page 161 |
Page 162 |
Page 163 |
Page 164 |
Page 165 |
Page 166 |
Page 167 |
Page 168 |
Page 169 |
Page 170 |
Page 171 |
Page 172 |
Page 173 |
Page 174 |
Page 175 |
Page 176 |
Page 177 |
Page 178 |
Page 179 |
Page 180 |
Page 181 |
Page 182 |
Page 183 |
Page 184 |
Page 185 |
Page 186 |
Page 187 |
Page 188 |
Page 189 |
Page 190 |
Page 191 |
Page 192 |
Page 193 |
Page 194 |
Page 195 |
Page 196 |
Page 197 |
Page 198 |
Page 199 |
Page 200 |
Page 201 |
Page 202 |
Page 203 |
Page 204 |
Page 205 |
Page 206 |
Page 207
