Triariodes Clark and Anderson

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: 344-346

publication ID 10.1649/0010-065X-73.2.343

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Triariodes Clark and Anderson

new genus

Triariodes Clark and Anderson   , new genus Fig. 1a– i View Fig

Diagnosis. In this genus, 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. Each tibia is armed with a terminal spur. The rectangular lobe at the apex of the male abdomen is conspicuous. The aedeagus is asymmetrical and with the distal portion spatulate ( Fig. 1g– i View Fig ). This suite of characters distinguishes this genus from other genera. In the three known species, the color pattern is distinctive ( Fig. 1a– c View Fig ), with five long, dark stripes on each elytron (one sutural, one lateral, and three discal).

Using the dichotomous keys of Wilcox (1965), Clark (1998), or Riley et al. (2002), this genus would be identified as Triarius   . However, it can be distinguished from that genus by the characters mentioned above.

Description. Form elongate oval ( Fig. 1a– c View Fig ). Each frontal tubercle subrectangular, transverse, about twice as wide as long, with acute extension at anterior angle mesad of antennal fossa, narrowly meeting other frontal tubercle at posteromesal angle, delimited laterad by shallow depression, delimited posteriad by abrupt depression; genae short, with length subequal to width of basal maxillary palpomere; eyes separated from antennal fossae by distance subequal to width of antennomere 2; antennae nearly filiform. Pronotum with long seta at each anterior and posterior corner; lateral margins strongly carinate, lined with several short setae; anterior margin lacking carina, with dense row of short setae; posterior margin with narrow carina, lined with dense row of short setae. Elytra with humeri well-developed; basal calli weakly developed, not delimited behind by depression; epipleura broad in basal half, extremely narrow in distal half. Prosternal process narrowly separating front coxae; procoxal cavities open behind. Terminal ventrite of male strongly impressed, with large rectangular lobe at apex. Tibiae each with terminal spur; tarsal claws appendiculate. Aedeagus asymmetrical, with distal portion spatulate ( Fig. 1 View Fig ).

Type Species. Malacosoma vittipenne Horn, 1893   .

Etymology. The name of this new genus stems from the similarity to Triarius   . It should be treated as a masculine noun.

Comments. We place this genus within the section Scelidites, but the similarity to Triarius   is not necessarily demonstrative of a sister relationship. Phylogenetic analysis within the section has not yet been undertaken.


1. Head and femora largely pale brown; aedeagus in lateral view evenly upcurved for much of length, but rather abruptly bent before apex (at base of spatulate portion that is visible in dorsal view) ( Fig. 1g View Fig ) ............................. ................... Triariodes vittipennis (Horn)  

1´. Head and femora largely dark brown or black; aedeagus not as above .......................... 2

2. Aedeagus upcurved in lateral view ( Fig. 1i View Fig ) ........................... Triariodes admiratio Clark and Anderson, new species  

2´. Aedeagus irregularly sinuate in lateral view ( Fig. 1h View Fig ) .................... Triariodes segonku Clark and Anderson, new species