Crinoid like ?

[Audiorij]

Found st charles county Missouri. Looks like a crinoid segment but no center hole.  Instead has like a chip in one side.  

[Rockwood]

This shape may be found in the feeding arms of crinoids (echinoderms). The notch, in life, would have formed part of a groove which channeled food to the mouth.

[abyssunder]

Take a look here: https://pygs.lyellcollection.org/content/58/1/9

https://doi.org/10.1144/pygs.58.1.272

Fig. 1

British Wenlock calceocrinids. (A–R) Calceocrinid brachial ossicles from Wenlock Edge. (A, B) NNM RGM 544 454, facet (A) and three quarters view (B); note tuberculation on latus. (C, D) NNM RGM 544 414, facet (C) and three quarters view (D) of tall ossicle. (E, F) NNM RGM 544 415, facet (E) and three quarters view (F). (G, H) NNM RGM 544416, proximal facet (G) and three quarters view (H) of axillary ossicle. (I, J) NNM RGM 544 417, proximal facet (I) and three quarters view (J) of axillary ossicle. (K, L) NNM RGM 544 418, facet (K) and three quarters view (L). (M) NNM RGM 544 419, note narrow, V-shaped adoral groove. (N) NNM RGM 544 420, facet. (O) NNM RGM 544 421, facet. (P) NNM RGM 544 422, facet. (Q) NNM RGM 544 423, facet. (R) NNM RGM 544 424, facet. (S) Detail of the broken distal tip of an arm of the calceocrinid Synchirocrinus serialis (Austin MS in Salter, 1873), BMNH 40218, lectotype. Note the rounded outline. The narrow, V-shaped notch of the adoral groove indicates a close affinity with the brachial illustrated in (M), suggesting that the latter is also a distal brachial. More proximal brachials would, of functional necessity, have had broader adoral grooves (see text). Specimens coated with ammonium chloride for photography.

 

Edited March 26, 2021 by abyssunder