Cheapest priced copy (Rivals of Ixalan): $0.35 at Card Kingdom, near mint, their price list as of .
Sun-Crested Pterodon 
Creature — Dinosaur · 2/5 · Common · Rivals of Ixalan · #27
Flying
This creature has vigilance as long as you control another Dinosaur.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Rivals of Ixalan | 27 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 19 January 2018Gaining vigilance any time after the moment you choose to attack with Sun-Crested Pterodon won't cause it to become untapped, and losing vigilance after that time won't cause it to become tapped.