Fig. 5. Typical arm spine shape. A. Tapering (conical): distally ⅓ as thick as proximal diameter with a round cross-section; Pointed: distally half as thick as proximal diameter with a round cross-section; Cylindrical: same thickness at both ends with flat/round tip. B. Flat: distally half as thick as proximal diameter with oval cross-section. Red dashed lines show the ⅓ distal cross-section. The letters ʻaʼ and ʻbʼ illustrate the diameter of ⅓ distal and basal cross-sections, respectively. ʻa/bʼ shows the approximate ratio of these diameters.
Goharimanesh, M., Stöhr, S., Mirshamsi, O., Ghassemzadeh, F., &amp; Adriaens, D. (2021). Interactive identification key to all brittle star families (Echinodermata; Ophiuroidea) leads to revised morphological descriptions. <i>European Journal of Taxonomy</i>, 766(1), 1-63.
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