Neomallodon arizonicus

Large-bodied prionine beetle with 12 antennal segments in males. Distinguished from the closely related and similar-sized Prionus californicus by its blackish rather than reddish coloration and relatively broad pronotum. Males have highly developed antennae and are capable of flight. The species' large size and general prionine morphology place it among North America's largest longhorned beetles.

Oak woodland and canyonland habitats, particularly those with Gambel oak (Quercus gambelii). Found in sandstone canyonlands with mixed oak/pine/juniper vegetation at moderate elevations. Associated with living oak trees and stumps, with adult females observed in leaf litter at tree bases.

Southwestern United States and northern Mexico. Documented from southeastern Arizona, southern and central New Mexico, extreme northwestern Oklahoma, and northwestern Colorado. The species appears to be expanding its known range, with recent records from northeastern New Mexico and the Oklahoma panhandle representing northeastern outposts of its distribution.

Adults active during summer months, with flight activity observed during both day and night. Peak activity occurs during afternoon hours, though this may vary by locality.

Larval feeding habits not directly observed, but presumably feeds on roots of living oaks or in dead oak logs and stumps based on association with Quercus gambelii and related oak species.

• Quercus gambelii - presumed hostGambel oak; adult association and presumed larval host based on habitat and related species biology

Complete metamorphosis with presumably multi-year larval development underground, feeding on tree roots. Adults emerge in summer. Specific details of egg, larval, and pupal stages not documented.

Adults exhibit strong attraction to prionic acid lures, flying to the vicinity of lures from long distances. Males demonstrate distinctive searching behavior: upon landing near a lure source, they run rapidly on the ground while searching, often circling broadly or taking flight again without locating the precise source. This suggests prionic acid functions in long-distance detection while additional pheromone components may be required for precise localization. When disturbed, adults may assume a defensive posture with the body raised and supported on the posterior, holding this stance for several seconds before lowering and resuming movement.

Root-feeding larvae likely contribute to nutrient cycling in oak woodland ecosystems. Adults serve as prey for various predators and may function as pollinators when visiting flowers, though this has not been documented for this species specifically.

Of interest to coleopterists due to its large size and the challenge of locating populations. Prionic acid lures are used by collectors to detect presence of this and related Prionus species.

• Prionus californicusSimilar large size and 12 antennal segments in males, but distinguished by reddish coloration versus blackish coloration in N. arizonicus, and relatively narrower pronotum
• Prionus integerShares prionic acid attraction and grassland/oak woodland habitat associations, but smaller in size with different antennal structure
• Prionus fissicornisAlso attracted to prionic acid and active in similar habitats, but distinguished by highly segmented antennae (up to 30+ segments) placing it in subgenus Antennalia

• Cerambycidae
• Prioninae
• Prionini
• longhorned beetle
• oak-associated
• prionic acid
• pheromone attraction
• southwestern US
• Mexico
• antennal segments
• defensive posture
• root borer
• Gambel oak
• canyonland habitat
• nocturnal and diurnal activity
• range expansion
• Skiles 1978
• Casey 1912

• BugGuide
• GBIF taxonomy match
• Catalogue of Life
• Cerambycidae | Beetles In The Bush | Page 6
• 2018 Arizona Insect Collecting Trip “iReport” | Beetles In The Bush