What are the paired fleshy lobes beside a manta ray’s mouth called?

The paired fleshy lobes beside a manta ray’s mouth are called cephalic fins.

Cephalic fins are modified portions of the manta ray’s head. The ray can roll or extend them to help guide plankton-rich water toward its wide mouth while feeding. Their position gives manta rays their distinctive horn-like appearance.

Manta rays are filter feeders. They swim with their enormous pectoral fins and strain plankton from seawater using filtering structures in the mouth and gill region. Unlike stingrays, mantas lack a venomous stinging spine at the tail.

Two living species are widely recognized: the giant oceanic manta ray and the reef manta ray. Mantas are cartilaginous fish, related to sharks and other rays, but their broad wings and forward-facing feeding posture distinguish them from many bottom-dwelling rays.