| Code | Refererence is a source for: |
| D | Reference is source for greatest depth |
| E | Reference for farthest east |
| L | Reference for greatest live collected depth |
| M | Reference for maximum size |
| N | Reference for farthest north |
| S | Reference for farthest south |
| T | Reference designates lectotype, neotype, or type locality |
| W | Reference for farthest west |
| a | Reference contains picture of living animal |
| c | Reference provided classification used in database |
| d | Reference is source for shallowest depth |
| l | Reference for shallowest live collected depth |
| s | Reference contains synonomy |
| v | Reference regarded species as valid |