Isomerida fourneti

Tavakilian, Gérard L. & Santos-Silva, Antonio, 2019, New Hemilophini, Aerenicini and Calliini from French Guiana, transference and notes on Hemilophini (Coleoptera, Cerambycidae, Lamiinae), Zootaxa 4555 (4), pp. 507-522: 510-512

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Isomerida fourneti

sp. nov.

Isomerida fourneti  , sp. nov.

( Figs 4–7View FIGURES 1–12. 1–3)

Description. Male. Head (except brown antennal tubercles), prothorax, ventral side of meso- and metathorax (except brownish centro-basal area of metathorax), abdominal ventrites III –IV orange (except brown centro-basal area of III); palpi pale yellow; scape almost black; pedicel yellowish basally, almost black on remaining surface; antennomeres III –XI with basal pale yellow ring, gradually narrower toward XI; elytra irregularly orange on basal sixth (this area smaller laterally), blackish on remaining surface; femora yellowish; tibiae yellowish on basal 2/3 dark brown on distal third (less so on protibiae); tarsomeres I –III yellowish basally, dark brown on remaining surface of I –II, dark reddish brown or brown on III; tarsomere V yellowish brown basally, gradually brown toward apex; abdominal ventrites I –II and V dark brown.

Head. Frons, vertex and area behind eyes finely, moderately abundantly punctate; with grayish white pubescence not obscuring integument (slightly denser on some areas, and more distinct or less so depending on angle of light source), interspersed with moderately long, erect, sparse pale yellow setae. Antennal tubercles with grayish white pubescence not obscuring integument, more brownish toward upper eye lobes. Genae finely, sparsely punctate; with grayish white pubescence not obscuring integument, gradually sparser toward glabrous apex. Submentum smooth, glabrous. Distance between upper eye lobes 0.27 times length of scape, 2.2 times width of an upper eye lobe; in frontal view, distance between lower eye lobes 0.70 times length of scape. Antennae 1.65 times elytral length, reaching elytral apex at about middle of antennomere IX; scape long, erect, moderately sparse yellowish brown setae on ventral side of distal third (gradually longer and more abundant toward apex); pedicel with long, erect, sparse brown setae ventrally; antennomere III with long, erect, abundant dark brown setae ventrally (from about as long as diameter of antennomere to slightly longer); antennomere IV with erect setae as on III, but sparser; antennomere V with sparse dark brown setae (longer than diameter of antennomere); antennomeres VI –VII with erect setae as on V, but sparser; antennomeres; antennomeres VIII –X with a few long, erect dark setae on ventral side of apex; antennal formula (ratio) based on length of antennomere III: scape = 0.83; pedicel = 0.17; IV = 0.70; V = 0.55; VI = 0.53; VII = 0.53; VIII = 0.49; IX = 0.49; X = 0.42; XI = 0.49.

Thorax. Prothorax distinctly transverse; with large conical tubercle placed about middle of sides (with blunt apex); sides slightly divergent from base to lateral tubercle, distinctly convergent from lateral tubercle to distal margin; base distinctly wider than apex. Pronotum with elongate, distinct gibbosity centrally, from near base to middle, slightly distinct from this point to near distal margin; with large, moderately distinct circular gibbosity each side of central area; moderately coarsely, abundantly punctate on basal quarter; with yellowish white pubescence obscuring integument (more whitish depending on angle of light source) except on top of gibbosities, interspersed with short, erect, sparse yellowish white setae. Sides of prothorax with pubescence as on pronotum, but exposing integument toward ventral side, especially on area close to head. Prosternum and ventral side of meso- and metathorax with yellowish white pubescence not obscuring integument. Scutellum with yellowish white pubescence not obscuring integument, mainly laterally. Elytra. Moderately coarsely, abundantly punctate on basal third, gradually finer, sparser toward apex; with longitudinal carina on center of dorsal surface, gradually less conspicuous toward apex; humeral carina well-marked from humerus to near apex; lateral carina well-marked, parallel and near to humeral carina from base to near apex; with very short, abundant yellowish white pubescence not obscuring integument, interspersed with moderately short, erect yellowish brown setae, more abundant on distal third. Legs. Femora with yellowish white pubescence distinctly exposing integument. Metatarsomere I 0.8 times length of II –III together.

Abdomen. Ventrites with yellowish white pubescence not obscuring integument (more grayish white on ventrites I –III and V due to dark integument); apex of ventrite V truncate, widely emarginate centrally.

Dimensions, male. Total length, 11.15; prothoracic length, 1.9; basal prothoracic width, 2.45; distal prothoracic width, 2.20; widest prothoracic width, 2.80; humeral width, 3.40; elytral length, 8.05.

Type material. Holotype male from FRENCH GUIANA: Saül (Route de Belizon), 23.VII.1982, A. Fournet col. [# 361 ex collection IRD] ( MNHN). 

Remarks. Isomerida fourneti  sp. nov. resembles I. albicollis ( Laporte, 1840)  . According to Martins & Galileo (2014b), I. albicollis  shows notable variation in the color of integument and pubescence. However, I. invicta  differs from I. albicollis  by structural features: prothoracic lateral tubercle very noticeable, distance between apices of tubercles distinctly wider than basal prothoracic width; distance between upper eye lobes shorter than 2.5 times width of a lobe; ventral erect setae on antennomeres shorter and distinctly spare at antennomere V ( Fig. 7View FIGURES 1–12. 1–3). In I. albicollis  ( Figs 8–10View FIGURES 1–12. 1–3), the prothoracic lateral tubercle is less prominent, and the distance between apices of the tubercles is equal to about basal prothoracic width, distance between upper eye lobes equal to about 3.5 times width of a lobe (in some specimens wider), and ventral erect setae on antennomeres longer and abundant at antennomere V ( Figs 11–12View FIGURES 1–12. 1–3). Although the holotype and paratype of I. invicta  are females ( Fig. 13View FIGURES 13–21. 13; see photograph of the holotype at Lingafelter et al. 2018), it is possible to conclude that the new species is not the male of that species because the prothorax is notably transverse and the lateral tubercles are much more protruding.

The inclusion of the new species in the key from Martins & Galileo (2014b) is not possible due to problems in the alternative of couplet “13” (dimensions and dorsal carina of the elytra).

Etymology. In honor of Alain Fournet, phytopharmacologist colleague of the first author who generously offered this unique specimen.


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Museum National d'Histoire Naturelle