The authors examined specimens of the Sinaloan mastiff bat (M. sinaloae) and found that individuals in the Yucatán Peninsula were morphologically distinct from other regions.

[2] The genus name Molossus refers to the ancient Molossus breed of shepherd dog,[3] while the specific name alvarezi honors the late José Ticul Álvarez Solórzano for his significant contributions to the development of Mexican mammalogy.

It is considered medium-sized for a bat of its genus, with a forearm length of 42.7–47.4 mm (1.68–1.87 in).

[2] Molossus alvarezi is found in Mexico in the states of Quintana Roo and Yucatán.

[1] Its range also includes Honduras and French Guiana.