Desicasta purpurascens ( Schoch, 1898 )

Ratcliffe, Brett C., 2013, A Revision of the Neotropical Genus Desicasta Thomson (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini), The Coleopterists Bulletin 67 (4), pp. 447-456 : 452-453

Desicasta purpurascens ( Schoch, 1898) ( Figs. 10–14 )

Moscheuma purpurascens Schoch 1898: 108 (original combination). Type not found.

Type locality: “ Rioja, northern Argentina.”

Description. Length 19.1–24.9 mm; width across humeri 9.5–12.2 mm. Color of head, venter usually, and legs shiny black; metasternum, metepisternum, metacoxae, and abdominal ventrites rarely reddish brown; pronotum and elytra velutinous, black or bright reddish brown (almost orange) or (rarely) a mixture of both; pygidium opaque, black or reddish brown. Head: Lateral margins weakly elevated. Frons and

(2): Madamas Bay, Morne Bleu. SAN JUAN- LAVENTILLE (7): Maracas Bay, Maracas Bay Road (mile post 6). NO DATA (8).

VENEZUELA (7). BOLÍVAR (2): La Paragua, Upper Caura River . DISTRITO CAPITAL (1): Caracas. TÁCHIRA (3): Cordero, Río Frio , San Cristóbal . MIRANDA (1): Parque Nacional Guatopo.

NO DATA (19).

Temporal Distribution. January (3), April (1), May (5), June (4), August (4), September (50), October (103), November (16), December (14). September–October is the period of greatest adult activity.

Diagnosis. Desicasta lobata is distinguished by rugulose sculpturing on the elytral apices behind the apical umbones (as opposed to sparsely punctate in D. reichei or velutinous in D. purpurascens ); with two distinctly elevated, longitudinal costae on each elytron ( Fig. 4 ); and males with elytra opaque and appearing “greasy” ( Fig. 4 ), while the females are shiny ( Fig. 5 ) (elytra in females and both sexes of D. reichei are shiny, while the elytra in D. purpurascens are velutinous). obliquely away from ventral axis of body ( Figs. 11–12 ), apex broadly rounded in ventral view. Abdominal ventrites nearly smooth in central third, lateral thirds with sparse, large punctures, punctures usually denser in females. Legs: Protibia slender in males, with 3 subequally spaced teeth, basal tooth often obsolete. Protibia in females broader, strongly tridentate. Parameres ( Figs. 13–14 ): In caudal view, form elongate, apices broadly rounded, each with small, lateral spine.

Distribution. Desicasta purpurascens is known from only a few localities in Colombia, Ecuador, Peru, Bolivia, Brazil, and Argentina. It seems to be an uncommon species.

Locality Records. 39 specimens from AMIC, BCRC, CASC, CMNH, MNHN, SLTC , and ZMHU.

clypeus weakly, longitudinally tumescent at middle. Surface with punctures moderate in size and density, glabrous. Clypeus at apex with deep, U-shaped emargination ( Fig. 10 ), not reflexed. Eyes moderate in size, interocular width equals 3.5–4.0 transverse eye diameters. Antenna with 10 antennomeres, club slightly longer than antennomeres 2–7 in both sexes. Pronotum: Surface usually obscured by velutinous covering; when occasionally or partially exposed, punctures moderate in size and density. Sides with thick marginal bead, bead becoming obsolete at posterior angle. Elytra: Surface usually obscured by velutinous covering; when occasionally or partially exposed, punctures moderate in size and density. Disc with 2 nearly obsolete, parallel costae terminating at weak apical umbone. Apices at suture obtusely rounded to weakly subacute. Pygidium: Surface arcuately to concentrically strigulopunctate; males with minute, pale setae; females with short, black setae. In lateral view, profile weakly convex. Venter: Setae black. Mesometasternal process in lateral view subrectangular to bluntly rounded, strongly protruding

ARGENTINA (2). LA RIOJA (1): La Rioja . NO DATA (1).

BOLIVIA (17). CHAPARE (1): No data. NORD YUNGAS (16): Rio Songo (= Zongo).

BRAZIL (6). MATO GROSSO (3): Chapada, Cuiabá . RIO DE JANEIRO (1): Rio de Janeiro . RORAIMA (2): Caucalandia.

COLOMBIA (1). NO DATA (1).

ECUADOR (1). MORONA SANTIAGO (1): Sucua.

PERU (11). CHANCHAMAYO (5): La Merced, No data. HUALLAGA (1): Aquaytia. MAYNAS (1): Iquitos. SATIPO (1): Satipo. NO DATA (3).

NO DATA (1).

Temporal Distribution. January (1), June (9), August (1), September (1), October (3). Too few specimens have label data with the month of collection to indicate a reliable temporal distribution.

Diagnosis. Desicasta purpurascens is probably the easiest species in the genus to identify because of its distinctive, velvety black or velvety bright brownish red dorsum and shiny black venter. It is the only species of Desicasta with velutinous elytra.

Natural History. Nothing is known of the life history of this species. The sparse label data indicate specimens have been collected at elevations of 300–1,000 m.

Figures

Fig. 10. Desicasta purpurascens.

Figs. 11–14. Desicasta purpurascens. 11–12) Lateral view of form of mesometasternal process showing variation; 13–14) Parameres.

Figs. 4–5. Desicasta lobata. 4) Male; 5) Female. Images courtesy of Julien Touroult (Paris, France).