During the forty-eight hours I spent killing Potamides as part of the Jaggedpine Hunter achievement I saw her five times. By far the most common of the Potamides on the list but still by no means common.
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Maulis Thefool, Ranger of the 86th season on Firiona Vie...
[Sat Apr 21 18:18:52 2018] Targeted (NPC): Lameriae the Alluring [Sat Apr 21 18:18:53 2018] Lameriae the Alluring - </c><c "#E1B511">a rare creature</c><c "#808080"> - scowls at you, ready to attack -- You could probably win this fight. [Sat Apr 21 18:19:23 2018] You have slain Lameriae the Alluring! [Sat Apr 21 18:19:31 2018] You tell your party, 'Lamariea's Amulet, Orb of the River's Essence, Polished Jade Tear' [Sat Apr 21 18:19:42 2018] --You have looted a Lamariea's Amulet.--
This mob dropped the Shawl of the Hatchling for me today. Rotted because no one in the zone cared to loot it, but she does have drops beyond her quest pieces.
She was spawned in the tunnels. When you swim in, take the first right and she was in that room. Don't know if that's a static spawn spot with a placeholder or if she's random since it was the first time I'd seen her after about fifteen queen kills but then again no one ever hunts the tunnels so she'd be a mighty rare pop regardless of if she's on a PH or random.