Amithao Thomson, 1878

Ratcliffe, Brett C., 2013, A Revision Of The Neotropical Genus Amithao Thomson, 1878 (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini), The Coleopterists Bulletin 67 (3), pp. 265-292 : 268-269

Amithao Thomson, 1878

Amithao Thomson 1878: 10 . Type species: Cotinis lafertei Thomson 1860: 31 , by monotypy.

Melisictes Thomson 1880: 268. Type species Cotinis erythropus Burmeister 1842: 263 , by monotypy (synonym).

Hologymnia Schoch 1895: 28 . Type species Gymnetis pyrrhonota Burmeister 1842: 267 , by monotypy (synonym).

Description. Scarabaeidae , Cetoniinae, Gymnetini . Form: Elongate, rhomboidal, robust, sides slightly tapering from humeri towards apex of elytra, dorsum nearly flat. Length 10.0–32.0 mm. Color black, dark reddish brown, brown, or green, shiny or velutinous, with or without cretaceous spots or bands on, variably, head, pronotum, elytra, pygidium, mesepimeron, metepisternum, coxae, femora, and abdominal ventrites. Head: Shape subrectangular, longer than wide. Clypeal apex weakly or strongly emarginate, reflexed. Frons and at least base of clypeus weakly, longitudinally tumid at middle and depressed either side of medial tumescence. Antenna with 10 antennomeres. Pronotum: Subtrapezoidal, widest near base, gradually convergent to anterior angles, basomedial lobe strongly produced posteriorly, lobe covering all but tip of scutellum. Sides with strong bead, anterior and basal margins lacking bead. Elytra: Widest at base, posthumeral emargination distinct. Bead present on lateral margins. Pygidium: Surface concentrically rugulopunctate or densely, concentrically strigulose, nearly flat to weakly convex. Venter: Mesometasternal process flat on ventral surface, in same plane as longitudinal axis of body, elongate and attenuate in lateral view ( Fig. 1 ) or bluntly rounded ( Fig. 16 ). Males with abdomen concave in lateral view and usually with medial, longitudinal depression. Females with abdomen flat to slightly tumescent. Legs: Protibia usually slender, with either 1, 2, or 3 teeth in males, wider and always tridentate in females. Metatibia at apex with 3 acute teeth and with 2 long, slender spurs. Parameres: In caudal view, form subrectangular, apices ranging from narrowly to broadly rounded, with or without a small tooth apicolaterally, divergent or convergent.

Diagnosis. Species of Amithao are distinguished from other genera of New World Gymnetini by a distinctly bilobed and emarginate clypeal apex, frons weakly and longitudinally tumid at middle (lacking armature that is present in most species of Cotinis and males of Allorrhina Burmeister ), and, in lateral view, a dorso-ventrally flattened, attenuate or bluntly rounded mesometasternal process that is parallel to the ventral axis of the body ( Fig. 1 ).

Only three other New World gymnetine genera possess a distinctly emarginate, or bilobed, clypeal apex: Desicasta , Guatemalica , and Hadrostica. Species in these genera have a mesometasternal process that is, in lateral view, either enlarged, subrectangular, with a bulbous apex, and deflected obliquely downwards ( Desicasta ) ( Fig. 2 ) or short, attenuate, and curving downwards and then recurving upwards at the apex ( Guatemalica , Hadrosticta ) ( Fig. 3 ). Some species of Hologymnetis (all species are velutinous) have an emarginate clypeal apex (not bilobed), but they all lack a prosternal “throat spur”, a distinguishing character for the genus since all other New World gymnetines possess this character.

Etymology. Since some species epithets in the literature have been inconsistently used both in the masculine and neuter forms for the same species, Thomas Rinkevich (Classics Department, University of Nebraska) assisted with interpreting the derivation of the generic name and the gender for any included species. He provided the following valuable commentary: “ Amithao is the Latinate form of Amythaon, the name of a Greek hero in the family of Jason, meaning ineffable, unspeakably great. The species names should be masculine if adjectival (as it is with albopictus ), but, if appositional, then the appositional should keep its own gender, as in Amithao haematopus (‘the red foot’). I have no exact reason why some are neuter in form, except that I noticed a couple of examples where in the 19th century the neuter form was listed, but then a synonym was suggested later using the correct masculine form. Amythaon was the father of Melampus (Black Foot), the seer along for the ride on the Argo, who understood the language of animals.” In Greek mythology, the Argo was the ship on which Jason and the argonauts sailed from Iolcos to retrieve the golden fleece.

Distribution. Species of Amithao are known from central Mexico to Venezuela, Colombia, and Ecuador with two species found in the West Indies.

Natural History. All species of Amithao are diurnal, although some species are attracted to lights at night. The adults are found from near sea level to 2,500 m and are usually attracted to ripe fruits placed in traps. Adult activity seems to conincide with the rainy season, although additional data are needed to verify this for all species. Only one larva, that of Amithao haematopus (Schaum) , has been described (Morón and Arce 2002). The larvae were found with the remnants of dead adult females in the axillary folds of leaves of an epiphyte, Acmaea sp. (Bromeliaceae) , in Chiapas, Mexico.

Nomenclature. Two species have been removed from Amithao . Amithao distigma Schoch, 1898 was removed from Amithao and placed in junior synonymy with Cotinis salicis Bates by Schürhoff (1934), and Ratcliffe and Warner (2011) removed it from Cotinis and placed it as a junior synonym of Gymnetina salicis (Bates) .

After examining the holotype of Amithao obscurus Schoch, 1896 at ETHC, I confirmed Gaston Ruter’ s 1967 determination that it is a female of Tiaocera rhinoceros (Gory and Percheron) . Interestingly, Schoch described A. obscurus as new on two separate occasions ( Schoch 1896, 1897). The specific epithet dates from the 1896 publication, whereas the 1897 publication is simply a verbatim repetition and has no separate nomenclatural standing.

Gymnetis marginicollis Burmeister was transferred to Guatemalica by Bates (1889) in Biologia Centrali-Americana, based upon the examination of only a couple of specimens then known to him. Unlike the other Guatemalica species , the mesometasternal process is not recurved downwards and then upwards but is, instead, nearly identical with the form seen in Amithao species . That, and the bilobed clypeus, make it congeneric with Amithao , and so it is here moved to Amithao .

Figures

Figs. 1–3. Mesometasternal process (lateral view) of 1) Amithao haematopus; 2) Desicasta reichei Thomson (image courtesy of the Natural History Museum, London, UK); 3) Guatemalica hueti Chevrolat.

Figs. 14–16. Amithao cavifrons. 14) Dorsal view; 15) Ventral view; 16) Lateral view.