Chiton virgulatus Sowerby, 1840

(Figures 3D, 7L)

Chiton virgulatus Sowerby, 1840: 824 . Chresonymy and synonymy in Bullock (1988).

Type material. According to Bullock (1988), the holotype is held in BMNH but Bullock mentioned that it was not found .

Type locality. According to Bullock (1988) at Bahía Kino, Sonora, México .

Material examined. Sixty– two specimens, BL 3.9–47.8 mm.

Habitat. In the intertidal, on large rocks with brown and red crusty algae patches. The rocks were found in shallow waters in an exposed, semi–dry rocky area; the chitons were collected on the rocks buried in the wet sand.

Remarks. Chiton virgulatus has radial, bifurcated, narrow ribs (Fig. 3D) on the head and tail valves and the lateral areas of the intermediate valves. Radula with unicuspid major lateral teeth, minor lateral tooth of about the same length as the central tooth (Fig. 7L).

Thorpe (1971) and Abbott (1974) agreed that Chiton stokesii and C. virgulatus are sympatric in the southern Mexican Tropical Pacific (MTP). Bullock (1985) and Reyes–Gómez (2016) rectified this assumption based on their expeditions in this region and the study of additional material. They found that C. virgulatus is restricted to the Gulf of California and C. stokesii to Central America. Chiton virgulatus is endemic to the Gulf of California and, contrary to other species of the genus Chiton present in the Mexican Pacific, it is characterized by a longitudinal and bifurcated tegmental sculpture.