Sympagus Bates

Hovore, Frank T. & Toledo, Víctor H., 2006, Review of the genus Sympagus Bates, 1881 (Coleoptera: Cerambycidae: Lamiinae: Acanthocinini), Zootaxa 1252, pp. 49-61 : 50-52

Genus Sympagus Bates

Sympagus Bates, 1881: 172 . ­ Blackwelder, 1946: 617; Chemsak et al., 1992: 147; Monné & Giesbert, 1994: 264; Monné, 2005: 133; Monné & Hovore, 2005: 197. Type species: Lepturges laetabilis Bates, 1872 , by original designation.

Stenopsilus Gilmour, 1959: 27 . ­ Monné & Giesbert, 1994: 262; Monné, 2005: 128; Monné & Hovore, 2005: 197. Type species: Stenopsilus bimaculatus Gilmour, 1959 , by monotypy and original description. New Synonymy.

Diagnosis

This genus can be distinguished by a combination of the following characters: front quadrate; eyes finely faceted; lower eye lobes only moderately large, subequal in height to gena below or at most 1.25 times taller; interocular space on vertex 1.5 to 2 times greater than width of upper eye lobe; antennal scape elongate, gradually enlarged or feebly clavate apically, apex simple, without a cicatrix or excavation; pro­ and mesosternal processes relatively broad, the former not less than one­half the width of an adjacent coxa, and the latter as wide or distinctly wider than adjacent coxa.

Redescription

Form moderately robust, broadly subcylindrical, slightly flattened dorsally, species small to moderate­sized; integument shining, red­brown to piceous, generally obscured by dense, very fine appressed pubescence of various colors on body and appendages, forming variable patterns on the pronotal disk and elytra; longer, erect setae on front of head and on basolateral margins of pronotum, shorter, stouter, suberect setae scattered on ventral surface of antennal segments, and dense and bristling on tibiae, particularly at apices. Head with front quadrate, evenly convex, frons short, broad, clypeus simple, short, rotundate­truncate apically, gena broad, simple, antennal tubercles elevated, rounded, transverse, protruding laterally over eyes, vertex impressed behind antennal tubercles; eyes finely faceted, lower lobes moderately large, equal to or 1.25 times taller than gena below, upper and lower lobes connected by 3–4 rows of facets and consisting of about 9 rows of facets at widest point, separated on vertex by 1.5 to 2 times the width of lobe; antennal scape elongate, attaining elytral base, subcylindrical, expanded or feebly clavate apically, apex simple, not excavated, second segment short, ovate, flagellar segments filiform, very slender, simple, at most feebly expanded at apex, surpassing elytral apices by about 6–7 segments in male, 5–6 in female, third segment subequal or equal in length to scape, fourth slightly shorter, segments 5–10 subequal to one another, slightly shorter than fourth, segment 11 usually slightly longer than scape. Scutellum short, broadly rounded or ligulate. Pronotum stout, about one third wider than long, disk convex or slightly impressed medially, without dorsal tubercles, sides rounded, narrowly convex or feebly tuberculate at basal one­third, tubercles obtusely rounded, transverse basal impression on disk behind tubercles; prosternum simple, narrow in front of coxae, procoxal process moderately broad, feebly arcuate, narrowed between coxae to one­half to two­thirds width of adjacent coxa, apex of process broadly expanded, closing procoxal cavities behind; mesosternum narrow, strongly impressed in front of coxae, mesosternal process abruptly elevated and arcuate to coxae, plane or feebly impressed between coxae, as wide or wider than adjacent coxa, apex feebly expanded before coxal sutures; metasternum broadly flattened medially, sides rounded or slightly inflated. Elytra about one­third longer than humeral width, parallel­sided to near apex, humeri rounded, feebly produced, disk slightly convex around scutellum, feebly impressed medially, apices sinuate­truncate or emarginate, outer angle angulate­dentate. Legs robust, femora moderately strongly clavate, tibiae and tarsi simple, apical two­thirds of male foretibia excavated beneath, densely setose, foretarsi simple, not expanded or fringed; metatarsi with basal segment short, subequal to, or slightly less than, the length of the following two segments together. Abdomen broad, convex in both sexes, more so in female, basal sternite as long as following two sternites together, sternites 2–4 narrow, subequal in length, male apical sternite slightly longer than fourth, rounded to apex, apical margin variable, usually broadly emarginate, female apical sternite tapering, more elongate, longer than preceding two sternites together, apical one­half of terminal sternite and tergite together slightly protruding beyond elytral apices.

Remarks

Atrypanius and Nyssodrysina both contain species which are superficially similar to Sympagus in appearance, but both of these presently may include species which are not strictly congeneric. Based upon the type species of each genus ( Atrypanius conspersus (Germar) ; Nyssodrysina haldemani (LeConte)) , both of these genera differ from Sympagus by having the front of the head rectangular, eyes coarsely faceted, lower eye lobes three times or more taller than the gena below, upper lobes separated on the vertex by the width of the upper eye lobe or less; the antennal scape relatively shorter, stouter, and more evenly cylindrical, apically emarginated or with a small dorsal cicatrix; and the elytral apices rounded, truncate, or angulate, but not dentate laterally. Atrypanius conspersus has lateral pronotal tubercles similar in configuration and placement to those of Sympagus , but N. haldemani has acute, posteriorly angulated lateral tubercles, situated at the terminus of the basal impression. The sternal processes in A. conspersus are only slightly narrower than those of Sympagus , but N. haldemani has the prosternal process only one­fourth the width of the adjacent coxa and the mesosternal process not more than one­half the width of the adjacent coxa. Based upon characters of their respective types, most of the other species presently included within Atrypanius are not strictly congeneric, and many of them may be better placed in Nyssodrysina .

Stenolis Bates, 1864 , superficially resembles Sympagus in the form of the head, antennae and pronotum, but is distinctly more elongate and slender in form. Based upon examination of color transparencies of dorsal and ventral views of the holotype specimen ( Stenolis undulata Bates, 1864 = Stenocorus angulatus Fabricius, 1801 ), and comparisons with several specimens of Stenolis angulata from Brazil and Panama, Stenolis sensu stricto also differs by the more elongate, rectangular front, upper eye lobes separated by about the width of the upper lobe, and much narrower pro­ and mesosternal processes, being about one­fourth and one­half the width of an adjacent coxa, respectively. Like Nyssodrysina , Stenolis appears to be polyphyletic as presently assembled.

Nyssodectes Dillon, 1955 , has head, pronotal and tibial characters similar to those of Sympagus , but its included species exhibit a less robust, more dorsally flattened and elongate body form. The type species, N. veracruzi Dillon, 1955 , may be easily distinguished from Sympagus by the very narrow prosternal process (not more than onesixth the width of an adjacent coxa), mesosternal process one­half the width of an adjacent coxa, and posterior tarsi with the basal segment about one­third longer than the following two segments together.

The genus Stenopsilus was described based upon a single female specimen from Manaus, Amazonas, Brazil ( Gilmour 1959), differentiated from Sphenopsilus Bates, 1885 (= Cobelura Erichson, 1847 ) and Stenolis by the unarmed pronotal sides, smaller lower eye lobes, quadrate front, and having the mesosternal process very broad. The proposed synonymy with Sympagus is based upon examination of a photograph of the type specimen of S. bimaculatus and of a series of specimens from Amazonian Ecuador perfectly matching the type. Stenopsilus bimaculatus shares the synapomorphies supporting Sympagus , with the prosternal process slightly narrower than that of Sympagus laetabilis , but within the range of variation exhibited by other included species. The relative widths of the sternal processes vary differentially within series of material examined of many acanthocinine species, and their use herein in defining genera is supported by other characters. Overall, the characters which defined Stenopsilus are consistent with those exhibited by all of the species presently included in Sympagus .