Methia enigma Martins, 1981

Nearns, Eugenio H., Swift, Ian P. & Santos-Silva, Antonio, 2023, Three new species of longhorned beetles (Coleoptera: Cerambycidae) with notes on additional taxa, Zootaxa 5228 (2), pp. 137-156 : 138-140

Methia enigma Martins, 1981

Figures 1–2

Methia enigma Martins, 1981: 12 ; Monné, 1993: 25 (cat.); Monné & Giesbert, 1994: 30 (checklist); Martins & Galileo, 1997: 172; Di Iorio, 2004: 18 (distr.); Martins & Galileo, 2004: 12, 102; Monné, 2005a: 395 (cat.); Monné, 2022a: 475 (cat.).

Remarks. According to Martins (1981) (translated): “This species [ Methia enigma ] is very close to M. argentina [ Figs. 3–7 ] and M. tubuliventris due to the cuneiform appearance of the elytra. It differs from both by presenting the upper eye lobes contiguous.” This feature was used in Martin’s key to species of the genus (translated): “1. Upper eye lobes contiguous,” leading to M. enigma ; “Upper eye lobes very close but not in contiguous (the distance between them is subequal to the diameter of two ommatidia)”, leading to M. argentina Bruch, 1918 and M. tubuliventris (Gounelle, 1913) .

Martins & Galileo (1997) reported (translated): “3(2). Upper eye lobes contiguous; elytra brownish, unicolorous or slightly more yellowish basally,” leading to M. enigma ; Upper eye lobes separated by a distance equivalent to a row of ommatidia; elytra yellowish with brownish apical third,” leading to M. argentina ; and “ Methia enigma resembles the males of M. argentina by the mesonotum without sulcus, and the elytra reduced in length, in this case, equal to 1.88 times the humeral width. In M. argentina , the elytra are also very short but different in color; they are yellowish in the two anterior thirds and reddish in the apical third. Furthermore, in M. enigma the upper eye lobes are contiguous in great extension and in M. argentina they are separated by a distance corresponding to a row of ommatidia. The sulcus of the metatibia occupies, in the middle, only one-fifth of the total length in M. enigma , while in M. argentina , it occupies the entire central region, except for the basal and apical quarters.”

Despite all these claims about the differences between the two species, it is probable that they are synonyms. The distance between upper eye lobes in specimens from Paraguay and Argentina are variable, from contiguous to very slightly separated and, when contiguous only a small area of each lobe touches (as in the types of M. enigma ). The color is also somewhat variable in the specimens from Argentina and Paraguay and can be equal in both species. The paratypes of M. enigma have the length of the sulcus of the metatibiae as in males of M. argentina , and not different as reported by Martins & Galileo (1997). The only reliable difference found by us in the specimens deposited at MZSP collection, is the number of ommatidia between the upper and lower eye lobes: one row in specimens from Argentina, identified as M. argentina ( Figs. 4, 7 ); two rows in specimens from Paraguay, identified as M. enigma ( Fig. 2 ). See photographs of these species on Bezark (2022).

The study of a larger series of specimens from Argentina and Paraguay is required to corroborate this difference. For now, we consider the two species as different, but point out that the key from Martins (1981) and Martins & Galileo (1997) does not adequately separate them.

Material examined. Methia argentina — ARGENTINA, Catamarca: La Cienaga ( Belén ), 2 males (det. By Bruch), I.1926, Weiser Woltrs leg. ( MZSP) . PARAGUAY (new country record), Boquerón: Est. Agropil S.A., 1 female, 23.X.1990, C. Aguilar leg. ( MZSP) .

Methia enigma — PARAGUAY, Alto Paraguay: Chaco Territory , Abt. [about] 150 miles W of Puerto Casado, 2 paratypes male, no date and collector indicated ( MZSP) .

Figures

FIGURES 1–7. Methia spp. 1–2) Methia enigma Martins, 1981, paratype male: 1) Dorsal habitus; 2) Eye. 3–4) Methia argentina Bruch, 1918, male from Argentina (Catamarca): 3) Dorsal habitus; 4) Eye. 5) Methia argentina, female from Paraguay (Boquerón): Dorsal habitus; 6) Ventral habitus; 7) Eye.