Sphallambyx mexicanum Galileo & Martins, 2007

Santos-Silva, Antonio, Botero, Juan Pablo & Galileo, Maria Helena M., 2018, On Sphallambyx mexicanum and key to species of Sphallambyx (Coleoptera, Cerambycidae, Cerambycinae), Zootaxa 4429 (3), pp. 572-576 : 572-575

Sphallambyx mexicanum Galileo & Martins, 2007 ( Figs 1–9 )

Redescription. Male ( Figs 1–5 ). Integument mostly black; glossa, paraglossa and palpi dark reddish brown, slightly light on apex of palpomeres; antennae gradually dark brown toward apex; femora with wide light ochraceous area from at about middle to distal fifth; tibiae with distal quarter light ochraceous, darkened on extreme apex; elytra light ochraceous except following dark brown, almost black areas: longitudinal band along suture, not reaching humerus, triangular on base (this area slightly surpassing basal quarter), abruptly narrowed at apex of triangular area (somewhat dentate at outer side), following along suture as wide band to near middle, with outer side slightly concave, abruptly widened from this point to at about base of distal quarter (basally forming rounded lobe), then gradually narrowed to apex; spot under humerus and epipleura.

Head. Frontal plate convex, subtriangular, distal margin rounded, slightly delimited laterally, finely, shallowly, sparsely punctate, with minute, sparse golden setae; remaining surface of frons slightly coarser, more abundantly punctate (punctures shallow), with minute, sparse golden setae; area between frons and clypeus, widely, deeply sulcate between frontolateral ridges; frontolateral ridges elevate, finely, sparsely punctate, with minute, sparse golden setae; antennal tubercle fused at base with frontolateral ridge, together Y-shaped, widened, rounded at its posterior apex, finely, sparsely punctate, with minute, sparse golden setae; with moderately elevate and wide carina close to antennal tubercles, with distinct sulcus between them; median groove well marked from clypeus to posterior margin of eyes, gradually widened from clypeus to its apex; area on each side of median groove with distinct carina, gradually elevate and widened toward level of upper eye lobes; area on each side of central carinae and at its apex deeply sulcate (these sulci straightly divergent from area between antennal tubercles to its apex); remaining surface of vertex and area behind upper eye lobes opaque, shallowly, abundantly punctate, glabrous on vertex, with minute, sparse golden setae behind upper eye lobes and a few long, erect, yellowish setae close to eye. Area behind lower eye lobes distinctly tumid close to eye, longitudinally sulcate along distal half of tumid area (sulcus gradually widened toward ventral side); coarsely rugose inside sulcus, with long, decumbent golden setae; area close to eye with a few long, erect yellowish-brown setae; remaining surface glabrous, finely, sparsely punctate, nearly smooth toward ventral side. Genae triangularly projected; finely, sparsely punctate interspersed with some coarser, shallow punctures; with long, erect, sparse yellowish-brown setae. Postclypeus carina-shaped at basal area, distinctly widened, projected forward laterally, obliquely, flat toward anteclypeus; carinashaped area finely, sparsely punctate, with minute, sparse golden setae, interspersed with a few long, erect yellowishbrown setae laterally; remaining surface with punctures coarser and shallower than basally. Labrum coplanar with anteclypeus on basal half and entire sides, concave at centrodistal area; with long, erect yellowish-brown setae on distal half, especially laterally. Gulamentum nearly smooth and glabrous on basal half, notably, widely elevate close to mentum, finely, moderately abundantly punctate, with minute abundant golden setae not obscuring integument between basal half and elevate area; with long, erect yellowish-brown setae on distal half. Distance between upper eye lobes 0.49 times length of scape, 1.46 times maximum width of one lobe; in frontal view, distance between lower eye lobes 0.78 times length of scape. Antennae 1.3 times elytral length, reaching elytral apex. Scape widened at basal inner side, widened at distal area; finely, moderately abundantly punctate except smooth distal area; with minute golden setae, slightly more abundant on outer side, interspersed with long, erect yellowish-brown setae throughout, especially ventrally. Antennomeres with golden setae, gradually denser from V; antennomeres III–V with long, erect yellowishbrown setae throughout, more abundantly ventrally, gradually sparser toward V; antennomere VI with long, erect, sparse yellowish-brown setae ventrally and apex; antennomeres VII–X with long, erect, sparse setae on distal area; antennomere XI curved at apex. Antennal formula (ratio) based on length of antennomere III: scape = 0.75; pedicel = 0.18; IV = 0.48; V = 0.65; VI = 0.65; VII = 0.68; VIII = 0.68; IX = 0.72; X = 0.70; XI = 1.26.

Thorax. Prothorax transverse, with distinct basal and distal constrictions (the latter more distinct). Pronotum with several large gibbosities between basal and distal constrictions, central one constant, usually somewhat club card-shaped, and remaining ones variable in number and shape due fusions and divisions; with golden pubescence covering some areas; with long, erect, golden setae basally and laterally. Sides of prothorax coarsely rugose. Prosternum deeply sulcate before distal constriction, coarsely rugose between procoxae and deep sulcus, slightly rugose distally; with golden pubescence close to procoxae, very sparse on remaining surface, interspersed with long, erect golden setae. Prosternal process longitudinally sulcate; nearly glabrous dorsally, with golden bristly setae laterally. Ventral side of mesothorax with golden pubescence, somewhat bristly on some areas. Metanepisternum and sides of metaventrite with golden pubescence; central area of metaventrite with moderately fine, sparse punctures, from each emerges long, erect golden setae. Scutellum with dense, golden pubescence except glabrous centro-basal area. Elytra. Surface reticulate (slightly distinct), with minute puncture at center of each cell (cells gradually less distinct toward apex); with a few long, erect yellowish-brown setae on basal quarter; outer and sutural angles with moderately long spine. Legs. Coxae with golden pubescence, denser in some areas, absent on others. Trochanters with long, erect golden setae ventrally. Femora with long, erect, sparse golden setae ventrally; metafemora with row of short, erect, abundant setae dorsally at about middle.

Abdomen. Ventrites I–IV with small area with golden pubescence on each side close to their apices; remaining surface with long, erect, very sparse golden setae. Ventrite V with short and long, moderately abundant golden setae on distal half.

Female ( Figs 6–9 ). It differs from male by the antennae shorter, 0.85 times elytral length, slightly surpassing middle of elytra.

Variation. Triangular basal area of central dark band of elytra slightly surpassing basal fifth; base of widened dark area placed after middle of elytra not forming rounded lobe; elytra with elongate, slightly marked brownish spot laterally; median groove not well-marked toward level of posterior ocular margin; antennae in male almost reaching elytral apex; golden pubescence on pronotum very variable, from absent to covering large area; pubescence of scutellum nearly covering entire surface; outer apical angle of elytra from slightly projected to distinctly spiniform; sutural angle of elytra with spine from short to moderately long.

Dimensions (mm), male/female. Total length, 39.51/41.80–44.32; prothoracic length, 5.76/5.71–6.79; basal prothoracic width, 6.75/7.06–8.14; distal prothoracic width, 5.85/5.53–6.43; maximum prothoracic width, 7.69/7.47– 8.77; humeral width, 10.03/11.43–11.70; elytral length, 29.34/32.31–34.25. One male and two females were measured.

Material examined. GUATEMALA (new country record), Izabal: 23 km SE Morales (800 m), 1 female, 23– 27.V.1995, Giesbert & Monzón col. ( FSCA) . COSTA RICA (new country record), Cartago : 15 km NE Turrialba, 1 female, 18–21.IV.1981, Giesbert col. ( FSCA) ; Cerro de la Muerte (57 km MachoGaft; 2500 m), 1 male, 2 females, VI.2015, A. Kozlov col. ( MZSP, AKPC) . PANAMA (new country record), Chiriqui: 7 km NE Fortuna Dam (at about 3000’), 1 female, 22–26.V.1984. E. Giesbert col. ( FSCA).

Remarks. Hovore (1989) reported: “ Sphallambyx chabrillaci [sic] Thomson—a single specimen of this large, black-and-yellow species, previously known from Brasil [sic], was beaten from dead wood in April, 15 km N Turrialba [EFGI. (Data and determination fide E. F. Giesbert.)”

According to Galileo & Martins (2007) (translated): “ HOVORE (1989) mentioned S. chabrillacii for Costa Rica. MARTINS & MONNÉ (2005) believed that the presence of this species in this country should be confirmed since S. chabrillacii is only known from the east of Brazil. It is possible that the specimen mentioned by HOVORE is, in fact, S. mexicanum.”

Examination of specimens from Guatemala, Costa Rica, and Panama showed that the supposition by Galileo & Martins (2007) was correct. Also, examination of the holotype of S. mexicanum confirmed that the prothorax is illformed ( Fig . 9). Furthermore, apparently, the head is also abnormal, since the distance between upper eye lobes is wider than in the other specimens examined, and the head itself is somewhat wider too. According to the original description, the holotype of S. mexicanum, the only formally known specimen, is a female. Although the left antenna of the holotype does not have the antennomeres X–XI, and the right antenna does not have the antennomeres VIII–XI, apparently the length agree with the other female (apex of antennomere IX reaching, at most, middle of the elytra), while in the males examined the apex of antennomere IX distinctly surpass middle of the elytra. However, abdominal ventrite V is notably different from all other specimens examined (males and females), even considering the evident variation found.

According to Galileo & Martins (2007) (translated): “ Sphallambyx mexicanum sp. nov. is similar to S. chabrillacii by the elytral color pattern, but differs by the scape and glabrous pronotum.” However, the scape in S. mexicanum, although not pubescent, has long, erect and sparse setae, and the pronotum may or may not be pubescent, but never as pubescent as in S. chabrillacii. As additional differences between these two species we can add the following: head nearly glabrous ( Fig. 5 ) (distinctly pubescent in S. chabrillacii ( Fig. 10 )); dorsal surface of head with distinct and deep sulcus on each side of central area ( Figs 1, 4, 6, 8 ) (absent or nearly so in S. chabrillacii ( Figs 11, 13 )); dark area of elytra reaching base ( Figs 1, 6 ) (not reaching in S. chabrillacii ( Figs 11, 13 )); elytra without dark band laterally on basal half ( Fig . 3) (sometimes slightly darkened on this area) (always present, and remarkably dark in S. chabrillacii ( Fig. 12 )).

Figures

FIGURES 1–10.1–9, Sphallambyx mexicanum: 1, dorsal habitus, male; 2, ventral habitus, male; 3, lateral habitus, male; 4, head and pronotum, female; 5, head, frontal view, male; 6, dorsal habitus, female; 7, ventral habitus, female; 8, head and pronotum, holotype female; 9, ventral habitus, holotype female. 10, Sphallambyx chabrillacii, head, frontal view, male.

FIGURES 11–14.11–13, Sphallambyx chabrillacii, male: 11, dorsal habitus; 12, lateral habitus; 13, dorsal habitus, holotype of Criodion toledopizai Melzer, 1934. 14, Sphallambyx superbum, dorsal habitus, male.