Callistochroma Eya

Eya, Bryan K., 2015, Revision of the Genus Crioprosopus Audinet-Serville, and description of three new genera of Trachyderini (Coleoptera: Cerambycidae: Cerambycinae), Zootaxa 3914 (4), pp. 351-405 : 362-363

Callistochroma Eya , gen. nov.

Type species: Callistochroma viridipennis ( Latreille, 1811)

The following species are included in Callistochroma : C. cacica ( Bates, 1885) comb. nov., C. chrysiptera sp. nov., C. flavofasciata (Chemsak & Hovore, 2001) comb. nov., C. lampros ( Bates, 1885) comb. nov., C. rutilans ( Bates, 1869) comb. nov., C. viridipennis ( Latreille, 1811) comb. nov., and C. viridipurpurea sp. nov.

Description. Form moderate-sized to large, slightly tapering posteriorly; integument shining; pubescence sparse, long, erect, short, pale, dense at sides of meso-metasterna and abdomen. Head small; front short, deeply impressed transversely, each side with a deep pit, median line deep, extending onto vertex between a swollen area between eyes; mandibles arcuate, acute at apices; palpi short; genae small, subtruncate at apices; antennal tubercles broad, moderately elevated, apices rounded; eyes moderately large, finely faceted, upper lobes small, well separated; antennae 11-segmented, slender (male: extending beyond elytra; female: shorter than body to extending beyond elytra), scape conical, sparsely, finely punctate, carinate over basal ½ to ¾, segments from fourth densely clothed with very short, appressed, pale pubescence, basal segments with a few, short, erect, black hairs beneath, segments 3 and 4 slightly enlarged at apices, remaining segments laterally carinate, third segment usually longer than first, eleventh feebly appendiculate. Pronotum broader than long; sides with tubercle at middle or slightly behind, (males: disc with sides of apical ½ densely, confluently punctate, basal ½ almost impunctate ( Fig. 11 ); females: disc usually glabrous ( Fig. 12 ); prosternum narrow (male: each side above coxae with a narrow, transverse, deeply punctate area; female: prosternum with sexual punctation reduced), pubescence, pale, erect, intercoxal process narrower than coxal cavities, arcuate, abruptly declivous behind, coxal cavities wide open behind; mesosternum with intercoxal process narrower than coxal cavities, very prominently produced with a blunt apex, abruptly, concavely declivous anteriorly ( Fig. 13 ), sides very finely clothed with silvery pubescence; metasternum with very fine pale pubescent at sides. Scutellum glabrous, longer than wide, acutely pointed apically. Elytra about twice as long as broad or longer, sides slightly tapering; punctures very fine, sparse; pubescence obsolete, except at apices and lateral margin; apices obliquely angulate, sutural angle rounded or acute, exterior angle dentate. Legs slender; hind femora linear, finely, sparsely punctate; tibiae slender, apically with two short spines, internally with a row of short, suberect hairs; hind tarsi slender, first segment about as long as following two segments together, third segment cleft to base. Abdomen finely pubescent at sides, segments 1–4 nearly glabrous in middle except for few erect hairs.

Remarks and diagnosis. In the description of Crioprosopus Audinet-Serville and Callona Waterhouse by Bates (1885) and Linsley (1962), respectively, they suggested a second group of metallic species that was generically distinct from these two genera; however, a new genus was not proposed. According to Bates (1880:76 and 1885:319), this group can be distinguished by the following characteristics: (1) very polished elytra; (2) very prominent mesosternum; (3) thorax of the male having the sculpture confined to a limited area towards each anterior angle; and (4) thorax in the female being quite smooth. This second group of Crioprosopus is herein referred to as Callistochroma . Some of the key features that distinguish Callistochroma from Crioprosopus Audinet-Serville are shown on Figs. 11–18 . Crioprosopus , in general, have more robust shorter antennae and the apices of the elytra rounded or truncate and usually without outer armature. Most of the metallic Crioprosopus species have a more densely clothed ventral vestiture. While the punctures found on the pronotal disc in male Callistochroma are limited to the area towards each anterior angle, the disc of male Crioprosopus is punctate throughout to the base. Also, the metallic species of Callistochroma can be distinguished from the metallic Crioprosopus by the differences in degree of sexual dimorphism, i.e., in the shape and size of the prothorax. In Callistochroma the overall prothoracic shape and size is similar in both sexes (i.e., the lateral margin of prothorax in both sexes have postmedian tubercles, and the side of the apical half, which is rounded or obtusely tuberculate). In the metallic species of Crioprosopus , males have an inflated prothorax with broad and obtuse lateral tubercles or sides dilated or rounded, while the females have a smaller glabrous disc. Many of the female examples with metallic green or blue elytra from Mexico labeled “ Callona rutilans ” in collections appear to be Crioprosopus species because these examples do not have the protuberant mesosternal process found in Callistochroma , and share the characters of ventral vestiture, shorter antennae, and the rounded or more truncated elytra apices of Crioprosopus . In general, considering the distribution of these two genera, most of the Callistochroma appears to be distributed southeast from Nicaragua into northern South America , whereas Crioprosopus is predominantly distributed from Costa Rica northward into North America and mainly centered in southern Mexico. One of the few species of Callistochroma with its distribution extending into central Mexico (Colima) is C. rutilans , and Crioprosopus with its distribution extending into South America is C. tricolor .

Etymology. The etymology of the genus Callistochroma is Callisto (or Kallisto) Καλλιστώ, Greek for “most beautiful” and chroma χρῶΜα "color."

Figures

FIGURES 11 – 18. Comparison of structural characters of Callistochroma and Crioprosopus: Callistochroma lampros: 11: prothoracic sculpture (male), 11 a: punctures confined to anterior angle; 12: prothoracic sculpture (female), 12 a: side of apical half of prothroax obtusely tuberculate; 13: prosternal and mesosternal intercoxal process, 13 a: mesosternal process obtusely tuberculate, extending below 13 b, 13 b: plane of prosternal intercoxal process; 14: elytral apices obliquely angulate, 14 a: outer armature. Crioprosopus basileus: 15: prothoracic sculpture (male), 15 a: disc densely punctate throughout; 16: prothoracic sculpture (female); 17: prosternal and mesosternal intercoxal process; 18: elytral apices rounded or subtruncate.