Allorrhina Burmeister, 1842

Ratcliffe, Brett C., 2015, A Revision of the Neotropical Genus Allorrhina Burmeister, 1842 (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini), The Coleopterists Bulletin 69 (1), pp. 91-113 : 91-113

Allorrhina Burmeister, 1842

Allorrhina Burmeister 1842: 251 .

Type species: Gymnetis concolor Gory and Percheron 1833: 76 , here designated. Burmeister (1842) stated he knew only this species based upon actual specimens, while the second species in his new genus, Gymnetis menetriesii Mannerheim , he knew only from the description. Accordingly, the former is designated as the type species. Gymnetis concolor is a junior synonym of Cetonia scabriuscula Swederus. Burmeister (1842: 806) belatedly recognized that C. scabriuscula Swederus belonged in Allorrhina .

Diagnosis. Form elongate, subparallel, slender to robust, slightly dorso-ventrally flattened. Length 11–29 mm. Color dorsally shiny dark green, reddish brown or piceous, or opaque light to dark reddish brown, plum, dark greenish gray, dark greenish black, or blackish gray, occasionally with weak metallic reflections. Venter most commonly shiny reddish brown or dark green, occasionally black. Cretaceous marks present or not on pronotum, lateral margins of elytra, pygidium, femora, and thoracic and abdominal sternites. Head: Shape subrectangular, frons of males longitudinally tumescent or with short, dorso-ventrally flattened horn projecting forward over clypeus, horn free at apex or not; clypeus with or without short, subrectangular or subtriangular horn at apex. Females with low, longitudinal tumescence on frons, apex occasionally barely free; clypeus with low, rounded or subrectangular, reflexed prominence at center or simply broadly rounded. Antenna with 10 antennomeres, club subequal to or distinctly longer than antennomeres 2–7. Pronotum: Shape subtrapezoidal, widest near base, gradually convergent to anterior angles, basomedian lobe strongly produced posteriorly, lobe covering all but tip of scutellum. Sides with slender, short or complete, marginal bead. Lateral margin usually strongly emarginate between middle and basal angle. Elytra: Widest at base, posthumeral emargination distinct. Complete or partial bead present on lateral margins. Apices usually slightly produced at suture. Pygidium: Surface with transverse, vermiform punctures or strigulae, setigerous; setae minute to short, most tawny, some black. Venter: Mesometasternal process, in lateral view, moderately protuberant, subparallel to ventral axis of body, apex broadly rounded ( Figs. 5 , 10 , 32 ). Abdominal ventrites 1–5 impunctate to sparsely punctate on central third, lateral thirds with moderately dense to dense, moderately large punctures. Legs: Protibia slender, unidentate, bidentate or weakly tridentate in males, tridentate in females. Parameres: Form (e.g., Figs. 3 , 28 ), in caudal view, subrectangular, apices usually broadly rounded with subapical tooth on lateral edge or acuminate and curving mesad.

Distribution. Species of Allorrhina are known from Venezuela and the Guianas in northern South America south to Argentina.

Diagnosis. As is the case with many other New World gymnetines, there seem to be few morphological characters, other than unreliable color and pattern, to circumscribe taxa, especially considering the similarity of the form of the parameres within genera. At least with Allorrhina and Cotinis , the armature of the head provides additional characters, although these should be used cautiously since this armature is subject to allometric growth exemplified by minors and majors. The characters of most taxonomic value for Allorrhina species are: dorsal color; absence or presence of cretaceous marks on the pronotum, elytral margins, pygidium, and ventrites; length; form and/or armature of the frons and clypeus; sculpturing of the pronotum and pygidium; and form of the parameres. The mesometasternal process is similar in all the species and is slightly elongate, parallel to the ventral axis of the body in lateral view, and with subparallel sides and a broadly rounded apex in ventral view (e.g., Fig. 5 ). One species is noticeably pubescent on the process ( Fig. 10 ), while in the remaining species the process is glabrous or nearly so (e.g., Fig. 32 ).

Allorrhina is closely allied to Cotinis in character states. Goodrich (1966) revised Cotinis and suggested Allorrhina and Cotinis were easily separated by the uniformity of the developed head armature (clypeal and occipital horns or projections) in both sexes of Cotinis species but not in Allorrhina species. Goodrich thought that males of Allorrhina all had well-developed clypeal horns and occipital horns with a free apex. My observations demonstrate this is not true for all Allorrhina species. Moreover, some Allorrhina species have similar, albeit reduced, clypeal projections in both sexes, and some Cotinis species have little or no armature on the head but merely prominences. Allorrhina species occur only in South America, while Cotinis species occur from the central USA southwards to northern South America.

Bates (1872) described Allorhina (sic) anomala , but this species is in the genus Argyripa Thomson ( Ratcliffe 1978) . Westwood (1874) described Allorhina (sic) hypoglauca from Nicaragua, and Janson (1877) placed it in junior synonymy with Allorhina (sic) lansbergei Sallé. This species is in the genus Argyripa ( Ratcliffe 1978) . Janson (1888) described Allorhina (sic) insignis from Panama, but this species is in the genus Chiriquibia Bates ( Ratcliffe 2014) . The genus Allorrhina now contains nine species, including the new species described herein from Argentina.

Natural History. Species of Allorrhina are diurnal. Unlike some species of Amithao Thomson, I have seen no records of any Allorrhina species being occasionally attracted to lights at night. The adults are found from near sea level to 1,800 m and are usually attracted to ripe fruits placed in traps. There are rare observations of species being found on a particular tree or flower, but their life history remains unknown. None of the larvae have been described.

KEY TO THE SPECIES OF ADULT ALLORRHINA

BURMEISTER, 1842

1. Pronotum shiny............................................2

1′. Pronotum opaque .........................................3

2. Pronotum dark reddish brown, black, or dark green, usually with metallic green reflection, lacking cretaceous marks. Elytra equally shiny. Mesometasternal process on metasternal portion glabrous ( Fig. 32 ).................. ......................... A. scabriuscula (Swederus)

2′. Pronotum reddish brown, with a cretaceous band on each lateral margin. Elytra opaque. Mesometasternal process on metasternal portion with long, dense, tawny setae ( Fig. 10 ) ............ A. denotata Abadie and Ratcliffe , new species

3. Cretaceous marks completely absent...........4

3′. Cretaceous marks present ............................ 7

4. Venter shiny metallic dark green................... ....................................... A. tridentata Moser

4′. Venter shiny dark reddish brown................5

5. Males with occipital horn elongate and dorso-ventrally flattened, extending to at least middle of clypeus, apex emarginate ( Fig. 2 ). Females with occipital tumescence at apex fused to clypeus, not free................ ............. A. carmelita (Burmeister) , in part

5′. Males with occipital “horn” short, not reaching middle of clypeus, apex rounded or arcuate, not emarginate ( Figs. 26 and 36 ). Females with occipital tumescence barely free at apex ....... 6

6. Occipital tumescence short in both sexes, apex broadly arcuate ( Fig. 26 ). Antennal club of females almost as long as entire stem ...... .............................. A. nigerrima Burmeister

6′. Occipital tumescence short in both sexes short, tapering to apex in males, evenly and narrowly rounded in females ( Fig. 36 ). Antennal club of females slightly longer than antennomeres 2–7 ................. A. soror Moser

7. Length 18.0 mm or greater..........................8

7′. Length 15.5 mm or less...............................9

8. Elytra with distinctly visible rows of punctures. Males on lateral edge of clypeus with forward-directed horn..................................... ...................... A. menetriesii (Mannerheim)

8′. Elytra lacking distinctly visible rows of punctures on disc. Males on lateral edge of clypeus lacking forward-projecting horn. Rare females with slender, cretaceous ring around metepisternum ................................... ............. A. carmelita (Burmeister) , in part

9. Pronotum coarsely punctate, with large, dense, shiny punctures. Each elytron with 2 distinctly raised costae on disc.......... A. nickerli Moser

9′. Pronotum with small, sparse punctures. Each elytron lacking raised costae on disc ............ ................. A. cincta (Gory and Percheron)

Figures

Figs. 1–5. Allorrhina carmelita. 1) Habitus; 2) Male head; 3–4) Parameres; 5) Mesometasternal process.

Figs. 9–12. Allorrhina denotata. 9) Habitus of holotype; 10) Mesometasternal process; 11–12) Parameres.

Figs. 32–34. Allorrhina scabriuscula. 32) Mesometasternal process; 33–34) Parameres.

Figs. 25–29. Allorrhina nigerrima. 25) Habitus; 26) Male, head, arrow indicates occipital horn; 27) Female, head, arrow indicates frontal tumescence; 28–29) Parameres.

Figs. 35–38. Allorrhina soror. 35) Habitus; 36) Male, head, arrow indicates occipital horn; 37–38) Parameres.