Triarius Jacoby, 1887

Clark, Shawn M. & Anderson, E. Russell, 2019, A Review of Triarius Jacoby, 1887 (Coleoptera: Chrysomelidae: Galerucinae: Luperini), with Descriptions of a New Genus and Four New Species, The Coleopterists Bulletin 73 (2), pp. 343-357 : 349-350

Triarius Jacoby, 1887

Figs. 2a–i , 3a–g

Triarius Jacoby 1887: 571

Type Species. Triarius mexicanus Jacoby, 1887 (by monotypy).

Diagnosis. The basal carina of the pronotum is complete. Although fine, it extends without interruption along the entire posterior margin. Each eye is narrowly separated from the base of the mandible by a distance subequal to the width of the basal maxillary palpomere. The length of the basal antennomere is subequal to the maximum diameter of the eye. The epipleuron is broad in the basal portion and very narrow in the distal portion. Each tibia is armed with a terminal spur. The rectangular lobe at the apex of the male abdomen is conspicuous. In these characters, Triarius is similar to Triariodes . However, the frontal tubercles of Triarius are only about as broad as long, being limited laterad by a shallow (sometimes rather inconspicuous) depression. In Triariodes , the depression is nearly absent, such that the tubercles are strongly transverse, closely approaching the eye. Moreover, the aedeagus of Triarius is symmetrical, with the distal portion only weakly spatulate, or not at all.

Comments. Within the subfamily Galerucinae , the nature of the tarsal claws (simple, appendiculate, or bifid) is extensively employed to diagnose genera or even taxa above the generic level. It is therefore remarkable that some species of Triarius have bifid claws and others have appendiculate claws. However, this situation is not unique among the New World genera in the section Scelidites, where claws are reported to be appendiculate, except in some species of Triarius . Although not previously reported in the published literature, the claws are also bifid in Scelida metallica Jacoby , while appendiculate in all other species of Scelida Chapuis. Beyond the section Scelidites, the lack of claw uniformity is not common, but also not unprecedented. For instance, all species of Erynephala Blake and some (but not all) species of Monoxia LeConte have bifid claws in males and simple claws in females. In males of Hyperbrotica Bechyné and Springlová de Bechyné , all claws are appendiculate in females, while only the hind claws are appendiculate in males, the others being bifid.

Figures

Fig. 2. Triarius species, dorsal habitus. A) T. pini, male, B) T. pini, female, C) T. trivittatus, D) T. nigroflavus, male, E) T. nigroflavus, female, F) T. melanolomatus, G) T. lividus, H) T. texanus, I) T. novoleonis.

Fig. 3. Triarius species, aedeagi, dorsal and lateral views. A) T. pini, B) T. nigroflavus, C) T. melanolomatus, D) T. lividus, E) T. trivittatus, F) T. texanus, G) T. novoleonis.