Authorities are looking for a champagne- or beige-colored Dodge truck in connection with a Friday morning hit-and-run crash with a bicyclist, a retired Sonoma State University professor who was gravely injured in the accident.

The suspect was driving a full-size Dodge pickup with a model year between 2002 and 2008, based on a side mirror and other wreckage found at the scene of the collision near Penngrove, CHP Officer Kerri Post said.

The truck would have its right side mirror sheared off and its front right headlight knocked out, with possible other damage to its right front as well, authorities said.

It was last seen headed southbound on Petaluma Hill Road toward Penngrove after swerving onto the shoulder and striking a bicyclist from behind near East Railroad Avenue, the CHP said.

The victim, a 65-year-old man known for riding his bike everywhere, was riding with at least one other companion on southbound Petaluma Hill Road near East Railroad Avenue when the truck swerved onto the shoulder and struck him, Post said.

The victim is a retired professor at SSU. The Press Democrat is withholding his name because authorities have been unable to track down family members to notify them of the 8:38 a.m. collision.

Rancho Adobe Fire Capt. Pete Albini said the cyclist suffered major head trauma and was unresponsive at the scene.

He never regained consciousness while medics prepared him for transport to Memorial Hospital, Albini said. He was was listed in critical condition on Friday afternoon.

Albini said the man's vital signs were strong, however, and firefighters hoped he would survive.

The cyclist had been wearing a helmet while riding his mountain bike, which was left crumpled by the impact of the truck, Albini said.

Officer Steve Fricke said anyone who sees a pickup matching the suspect vehicle description is asked to call 911 and report it.

Callers can dial CHP dispatch if the truck appears to have been abandoned, he said. That number is (707) 551-4100.