Triariodes admiratio Clark and Anderson, 2019

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 : 346-347

Triariodes admiratio Clark and Anderson , new species

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Fig. 1c, f, i

Diagnosis. The vittate elytra ( Fig. 1c ), in combination with the appendiculate tarsal claws, distinguish this species from others in the similar genus Triarius . Within Triariodes, this new species is externally very similar to T. segonku but is easily distinguished by the distinctive shape of the aedeagus ( Fig. 1i ).

Description of Holotype. Form elongate oval ( Fig. 1c ); body 6.5 mm long, 3.3 mm wide. Head black; prothorax yellow; scutellum black; elytra yellow, slightly paler than prothorax, with brown vittae; ventral areas largely dark brown, almost black; legs largely dark brown.

Head black, except distal portion of clypeus yellow; interocular distance slightly larger than 2/3 head width across eyes; posterior area of vertex smooth, shiny, nearly impunctate; anterior portion of vertex near frontal tubercles densely punctate and pubescent; each frontal tubercle glabrous, impunctate, subtriangular, transverse, slightly less than twice as wide as long, nearly contiguous with other frontal tubercle at posteromesal angle but separated by deep sulcus, delimited laterad by gradual depression, delimited posteriad by abrupt depression; mesal frontal ridge narrow, distinctly carinate; raised area of clypeus strongly transverse, about as wide as distance between eyes, only about as long as width of antennomere 1, densely pubescent behind, with row of long setae in front; distal portion of clypeus yellow, very thin, covering posterior portion of labrum; area posterior to eye and anterior to prosternum covered with long, dense, white pubescence; genae very short, with length subequal to width of basal maxillary palpomere, densely covered with comparatively short white setae. Labrum dark brown, rectangular, width 3.8 times as great as length and subequal to distance between lateral margins of antennal fossae, with transverse row of 6 long setae. Mandibles testaceous, tips piceous; maxillary palpi dark brown with pale brown tips, densely setose, acutely pointed towards apex. Eyes oval, each 2.6 times as long as broad, finely facetted, separated from antennal fossa by distance subequal to width of antennomere 2.

Antennae nearly filiform, extending to about middle of elytra. Basal 3 antennomeres yellow; distal 8 antennomeres black, covered with dense pubescence, with longer setae near apex of each antennomere; antennomere 1 slightly curved, shiny, rather densely setose, much longer than broad, with length subequal to that of antennomeres 2 and 3 combined; antennomere 2 about half as wide and less than half as long as antennomere 1, uniformly setose; antennomere 3 slightly longer than 2, nearly twice as broad at apex as at base; antennomere 4 nearly as long as antennomere 1, slightly broader at apex than at base; antennomere 5 slightly shorter than antennomere 4, distinctly broader at apex than at base; antennomeres 6–10 subequal in length to 5 and to each other, only slightly wider at apex than at base; antennomere 11 subequal in length and slightly narrower than antennomere 10, narrowed distad to acute point, with distal fourth separated from basal portion by shallow groove lined with relatively long setae, therefore nearly appearing to be distinct antennomere, although not freely articulated.

Pronotum widest near apical third, greatest width about 1.3 times as great as that of head, posterior portion slightly wider than head; shape transversely arched, surface glabrous, shiny, extremely minutely punctulate, punctures visible only upon close examination; blunt tubercle present at each anterior and posterior corner; lateral margins strongly carinate; anterior margin lacking carina, with dense row of short setae; posterior margin with narrow carina, lined with dense row of short setae. Scutellum black, equilaterally triangular, glabrous, impunctate, shiny.

Elytra 5.9 mm long, together about twice as wide as head, distinctly wider than pronotum, 4 times as long as pronotum. Humeri well-developed; basal calli obsolete, not delimited behind by depression; epipleura broad in basal half, extremely narrow in distal half. Discal surface glabrous, minutely, densely punctate, interpunctural areas shiny. Color of each elytron pale yellow with 5 brown, longitudinal stripes; stripe 1 adjacent to suture; stripe 2 very faint, nearly absent; stripe 3 beginning in subhumeral depression, extending to base of apical declivity; stripe 4 beginning behind humerus, extending to base of apical declivity; stripe 5 lateral, occupying epipleuron and adjacent area.

Body beneath dark brown, almost black, except prothorax yellow. Ventral areas of prothorax largely glabrous, shiny; anterior margin lined with fringe of long setae; posterior margin lined with comparatively short setae; prosternum anterior to coxae short, length subequal to maximum diameter of antennomere 1; posterior prosternal process very narrowly separating coxae; procoxal cavities open behind. Mesothorax shiny, glabrous. Metathorax densely covered with white pubescence throughout.

Abdomen sparsely covered with white pubescence in lateral areas, glabrous or sparsely pubescent in mesal area; terminal ventrite with strong mesal impression in distal half, with large rectangular lobe at apex.

Legs dark brown, except front tibiae paler brown; surfaces largely covered by dense white pubescence. Tibiae each with terminal spur. Basal tarsomeres broadened but distinctly narrower than tibial apex; claws appendiculate.

Aedeagus strongly asymmetrical, spatulate apically; with spatulate portion subrectangular, about as long as broad ( Fig. 1i ).

Holotype. “ MEXICO: Aguascalientes / 15 miles east Calvillo / July 11, 1983 / Kovarik, Harrison, / Schaffner ” (male, TAMU).

Etymology. The specific epithet “ admiratio ” is a Latin word meaning surprise. It was truly a surprise that this species, which is so similar in appearance to T. segonku , has such a dramatically different aedeagus. The epithet is treated as a noun in apposition.

Comments. Although there is only a single specimen, we have no doubt that this species is different from the others.

Figures

Fig. 1. Triariodes species. Dorsal habitus: A) T. vittipennis, B) T. segonku, C) T. admiratio. Head: D) T. vittipennis, E) T. segonku, F) T. admiratio. Aedeagus, dorsal and lateral views: G) T. vittipennis, H) T. segonku, I) T. admiratio.