The Lady is Blue. Atrapako on Eden, #1

Intrepid scientist solves mystery of scaly aliens. Dr. Lucy Stannis leads a quiet life as the chief biologist in the small human colony on Eden until an alien spaceship arrives. Undaunted by the scaled bodies and vicious claws of the formidable Atrapako, Lucy befriends the captain, Sa Kamizan Veedak. But, soon she grows suspicious of the aliens' intentions and believes they are hiding a secret.  Sa Kamizan is desperate to find a haven for his exiled people and he cannot permit the puny humans to scuttle his plans to settle on the fertile planet.
He longs to claim the beautiful human scientist as his mate, but he has sworn to conceal the Atrapako weakness. Yet Lucy's skills astound him at every new challenge, and he is forced to rethink his devious scheme to seize control of the colony. When conflicts with the arrogant Atrapako threaten to destroy Eden's peaceful society, Lucy must discover the aliens' secret vulnerability and work with Sa Kamizan to save the colony. If you like plucky heroines and mysteries where deceptions abound, then you'll enjoy this science fiction adventure and sweet romance with a surprise twist at the end.
Book 1 of Atrapako on Eden.