Pontobdella californiana is described parasitizing California coastal water big skates, Raja binoculata, and thornback guitarfish, Platyrhinoidis triseriata. Leeches are large, up to 70 mm in total length. The oral sucker has 2 pairs of linear eyespots and 2 pairs of lateral papillae. The caudal sucker is small and terminal, with a diameter less than maximum body width. Annulus a2 has 4 large conical tubercles dorsally and 4 smaller conical tubercles ventrally. Annuli a1 and a3 have 4 small tubercles dorsally and ventrally and 2 small tubercles laterally for a total of 10 tubercles on each of these annuli.