Glendale-based Tenrox, the developer of cloud-based, enterprise project management software, has been acquired by Texas-based Silverback Enterprise Group, Silverback said Thursday, as part of a rollup of a number of project management firms by Silverback. Financial terms of the acquisition were not disclosed. Silverback acquired Tenrox, along with fellow project management software firm PowerSteering Software. Silverback is venture backed by Austin Ventures, and acquired its first firm, Visionael, in September; Silverback says it is looking to create a pure-play, cloud PPM firm to address the $1.3 billion PPM software industry.