Careproctus melanurus

Actinopterygii: The Actinopterygii, or ray-finned fishes, constitute a class or subclass of the bony fishes. The ray-finned fishes are so called because they possess lepidotrichia or "fin rays", their fins being webs of skin supported by bony or horny spines ("rays"), as opposed to the fleshy, lobed fins that characterize the class Sarcopterygii. In terms of numbers, actinopterygians are the dominant class of vertebrates, comprising nearly 99% of the over 30,000 species of fish. (Wikipedia)

Platform: The ichthyolith has a basal stalk or lobe. (Note that platforms may not be preserved as well as the rest of the ichthyolith.)

Triangular: The base of the ichthyolith is the widest part.

Blunt: At least one cusp (or lobe) has an end that is more or less flat.

Cavity: The ichthyolith has a central nerve cavity. This is a base keyword included whenever an ichthyolith has a cavity, even when the cavity is further categorized with an additional keyword.