People living in La Mesa’s Serramar community overlooking Lemon Grove have a new neighbor. Earlier this week, a large Tyrannosaurus Rex sculpture standing in a concrete block mysteriously appeared on an empty plot on Monte Drive, a cul-de-sac off Eastridge Drive. The 10-acre parcel is slated for about 40 homes in a development called La Mesa Summit Estates. A resident of the area, Alice Hobson, who said she’s lived in La Mesa for 80 years, sent a photocopy of a photograph of the fenced-in dinosaur to The San Diego Union-Tribune and asked for an investigation. She said she doesn’t know how it got there.