Note: by "new", I mean unlisted by LSA and Associates in their Resource Management Plan for the Puente Hills (2007), which included a comprehensive species list of observed and potentially-present species.
Several western pygmy blue butterflies were flitting around their preferred foodplant, Australian saltbush, on the former Unocal property east of Hacienda Blvd. on 14 Aug. 2007. This is a widespread native species closely tied to weedy chenopods (saltbushes and relatives) that is probably fairly common in the hills.
A single giant darner was hunting in a disced/plowed border of one of the restoration sites in the same area today. It was nearly twice as large as the numerous gliders in the area, and showed the long, distinctively drooped abdomen. Usually found along streams, they should be looked for along Arroyo San Miguel and elsewhere.