Drop unenchanted jewelry and once, I found a HQ hopperhide on one! It now is on my Reinforced Hopperhide boots. What can I say? It was free and The boots are worth more!
I have never been to Marus Seru. However, you can find "a rhinobeetle hatchling" (note slight variation in name) in the crater around Shar Vahl. They con blue/yellow at level 1.