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We describe three new species: Canthon mezcalis Moctezuma, Sánchez-Huerta, and Halffter sp. nov. from the Valles Centrales region in Oaxaca, Mexico; Canthon hondurensis Moctezuma and Sánchez-Huerta sp. nov. from Honduras; and Canthon woodruffi Moctezuma and Sánchez-Huerta sp. nov. from Guanacaste, Costa Rica. Through the examination of external and genital morphology, Bayesian inference, and genetic distances based on the Kimura two-parameter model of nucleotide substitution, we confidently determined that the C. indigaceus species group is a monophyletic unit, which is integrated by a set of cryptic species.

The Canthon indigaceus species group represents a Typical Neotropical distributional pattern with wide penetration into the Mexican Transition Zone. This group consists of three species: C. (C.) indigaceus LeConte; C. (C.) chiapas Robinson; and C. (C.) chevrolati Harold. In this study, a new species for the group is described, C. (C.) cuixmala, collected along the tropical region of the Pacific coast and the Balsas River basin. The taxonomic status of members of the group were evaluated by comparing morphological characteristics and their biogeographic distributions. An updated dichotomous key is provided to separate members of this species group.

The third instar and pupa of Canthon bispinus Germar are described and illustrated. The larvae were reared from eggs laid by adults under laboratory conditions. Morphology of the two stages is analyzed based on characters at the generic level and compared to that of other species of Canthon Hoffmansegg. The third instar of C. bispinus can be distinguished by unique combination of chaetotaxy on the head, epipharynx, and mandibles and the number of stridulatory teeth on the maxilla. The setose pedium of the epipharynx is the main characteristic that differentiates the larva of C. bispinus from others in the genus. The morphology of both the larva and the pupa of C. bispinus conform with those characters diagnostic for the genus.

The food relocation, reproductive, and nesting behaviors of Canthon bispinus Germar were studied in terraria at ambient conditions outdoors with three food resources. Individuals fed upon fish meat and dog dung but did not use cow dung. Five kinds of food manipulation behavior were observed: rolling balls, rolling dung pellets, rolling small pieces of fish, direct burial, and stationary rotation of food. To attract females, males adopt the typical headstand position for the emission of sexual pheromones beside the food source or next to a rolled ball. Males make two sizes of balls to attract females: small balls (≤10 mm) and large balls (≥11 mm). Small balls are always abandoned intact or lightly bitten after mating; they are regarded as nuptial gifts offered by males only to copulate. Most often, sexual encounters occur at the food source or, less frequently, while the male is rolling a ball without the previous emission of pheromones. Only carrion-provisioned large balls (11–21 mm maximum diameter) are used for nesting. Males assume the principal role in making and rolling the ball. Most nests are telecoprid, compound, and shallowly buried. Parental care is performed by the couple; the male remains in the nest up to10 days, while the female usually remains for 30 to 32 days, just a few days prior to the emergence of the progeny. Survival rate was 92%. The carrion-provisioned brood balls are shaped like a figure eight or a pear. The egg chamber is separated from the provision chamber by a partition of soil material. As larval development advances, small excretions appear, increasing in number outside the ball.

The new species Parachorius semsanganussp. n. is described from Laos. This enigmatic Oriental deltochiline represents a \"morphological link\" between Parachorius and Cassolus by sharing characters of the two genera. The fact that Parachorius semsanganus cannot be unequivocally placed in either of these two genera stresses some more general problems of the current classification of Parachorius and Cassolus. Such problems can be solved only in the course of phylogenetic analysis, the need of which is briefly outlined.