Trogloderus costatus LeConte, 1879

Johnston, M. Andrew, Fleming, David, Franz, Nico M. & Smith, Aaron D., 2015, Amphidorini Leconte (Coleoptera: Tenebrionidae) of Arizona: Keys and Species Accounts, The Coleopterists Bulletin (mo 14) 69, pp. 27-54 : 52

Trogloderus costatus LeConte, 1879

( Fig. 1A–B )

Trogloderus costatus tuberculatus Blaisdell, 1909 Trogloderus costatus vandykei La Rivers, 1946 Trogloderus costatus nevadus La Rivers, 1942

Diagnosis. Body elongate. Elytral disc with four sharp, elevated costae, not counting the sutural costa which may be present or absent. Pronotum coarsely sculptured, either evenly tuberculate or grossly punctured with a tendency towards tubercles laterally. Anterior angles prominent, posterior margin strongly constricted. Profemora spined in males, sinuate to dentate in females.

Distribution. Mohave, Coconino, La Paz, and Yuma Counties, Arizona. New Mexico north to Wyoming and west to California.

Remarks. The genus Trogloderus is monotypic, with six subspecies, following the revision of La Rivers (1946), and is found in aeolian sand formations across the western United States. The two forms found in Arizona are quite distinct. In the west, following the Colorado River, is T. costatus vandykei ( Fig. 1A ), which is quite robust, lacks the sutural costa, has smooth elytral intervals, and a heavily punctate pronotum. The northern form ( Fig. 1B ) from the Arizona Strip is variously determined as T. costatus tuberculatus and T. costatus nevadus and is recognizable by the presence of a sutural costa, generally tuberculate elytral intervals, and evenly tuberculate pronotum. A revision of the genus is currently in progress.

Figures

Fig. 1. Amphidorini species, dorsal habitus. A) Trogloderus costatus, western form, B) T. costatus, northern form, C) Embaphion depressum, D) Embaphion contusum. Scale bars = 1 cm.