Gymnetina alboscripta ( Janson, 1878 ) Ratcliffe & Warner, 2011

Ratcliffe, Brett C. & Warner, William B., 2011, A revision of the genus Gymnetina Casey, 1915 (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini), Insecta Mundi 2011 (173), pp. 1-28 : 5-6

Gymnetina alboscripta ( Janson, 1878) , new combination

( Fig. 1-4 , 32 , 41 )

Gymnetis alboscripta Janson 1878: 301 . Original combination. Holotype female examined by BCR at RMNH.

Description. Length 18.0- 24.4 mm; width across humeri 10.0-15.0 mm. Color of head, pronotum, and pygidium black, shiny. Pronotum on lateral margin with slender, cretaceous band, band occasionally broken. Mesepimeron black along anterior edge, cretaceous along posterior margin (entirely black in 1 female). Metepisternum black with partial or complete cretaceous ring along margins. Elytron dark reddish brown to piceous (rarely black), with transverse, slender, sinuous, cretaceous band behind middle extending almost entire width of elytron ( Fig. 1 ), band rarely broken. Pygidium with large, subtriangular, cretaceous spot on each side, rarely spot reduced (absent in 1 female examined). Sternites 1-4 each with small to large, cretaceous spot or band on posterolateral margin; sternites 2-5 in males each usually with small to large, transverse, cretaceous spot or band on anterior margin either side of middle ( Fig 2 ), some spots variably absent. Legs and venter black. Head: Lateral margins weakly elevated. Surface densely punctate on frons, clypeus moderate in density; punctures small to moderate on frons, moderate to large on clypeus, setigerous (when not abraded away); setae short, moderate in density, black. Occiput smooth, shiny. Frons with weak (sometimes obsolete), median, longitudinal swelling. Clypeus with apex broadly subtruncate, strongly reflexed, sides weakly constricted just before antennal insertion. Interocular width equals 4.8-5.0 transverse eye diameters (slightly larger in 1 female). Antenna with 10 segments, club slightly longer than antennomeres 1-7 in males, subequal in length to antennomeres 2-7 in females. Pronotum: Surface impunctate or sparsely, minutely punctate on central third, punctures becoming large (some ocellate) and moderate in density on lateral thirds where setigerous (when not abraded away); setae sparse, short, black. Mesepimeron dorsally and on anterior face with sparse to dense, mostly large, setigerous punctures; setae short, black. Elytra: Surface almost smooth on disc behind scutellum to about middle of elytra, elsewhere with punctures glabrous, moderate in size and density (some in discernable striae), punctures becoming dense and large (some ocellate) laterally; sides near lateral margins, apical umbone laterally, and apical angles finely rugose. Apical umbone pronounced. Apices subacutely produced. Pygidium: Surface concentrically rugulopunctate, setigerous; setae very dense, short, black. In lateral view profile nearly flat. Venter: Setae brown to mostly black. Mesometasternal process flat on ventral surface, apex broadly rounded, anterior face oblique at about 45 o to longitudinal axis of body. Abdominal sternites each with center sparsely and minutely punctate, lateral margins moderately to densely punctate; punctures mostly large with black setae. Legs: Protibia slender in males, broader in females, tridentate in both sexes, basal 2 teeth closer to one another than is apical tooth to median tooth. Parameres: In ventral view, base of each paramere with small but distinct, basally projecting tooth ( Fig. 3-4 ).

Distribution ( Fig. 32 ). This species has been found only in southern Mexico, and the type specimen was described from “ Oaxaca.” 25 specimens examined from AMIC, BCRC, BMNH, CNCI, FMNH, HAHC, MAMC, MNHN, PHSC, RMNH, UCMC, UNAM, ZMHU.

MEXICO (25): GUERRERO (1): Amula. HIDALGO (1): Real del Monte. MEXICO (1): Coatlinchan. JALISCO (1): Autln. MORELOS (2): Almolonga, Oacalco, No data. OAXACA (10): Juquila Mixes, Matias Romero, Mitla, Oaxaca, No Data. TABASCO (3): Paraiso. VERACRUZ (2): Catemaco, No Data.

NO DATA (4).

Temporal Distribution. March (3), May (1), June (4), July (3), September (1). Too few specimens have label data with the month of collection to indicate a reliable temporal distribution.

Diagnosis. Gymnetina alboscripta is distinguished by a pronotum with a slender, cretaceous band along lateral margins; elytra with a slender, cretaceous, transverse band just behind middle ( Fig. 1 ); and mesepimeron usually with a cretaceous spot. Males, like those of G. howdeni , have a cretaceous spot on the posterolateral margin of sternites 1-4 (variably reduced) and on the anterior margin of sternites 2-5 either side of middle (variably reduced, but always with at least 1 spot). Unlike G. howdeni , they do not have the broad, cretaceous bands on the pronotum and elytra. The single, large female from Hidalgo lacked the cretaceous spots on the pygidium, and so would not fit in our key, but it matches all of the other characters for G. alboscripta .

Gymnetina alboscripta differs from G. salicis by the presence of a cretaceous spot on the mesepimeron (absent in G. salicis ) and by the presence on the elytra of a slender, sinuate, transverse, cretaceous band ( Fig. 1 ) (elytra with single, small, cretaceous spot near lateral margin in G. salicis ; Fig. 29 ). Males of G. alboscripta always have, even if reduced, a second, more median set of cretaceous spots on the abdominal sternites ( Fig. 2 ), whereas G. salicis males never have a second set of these marks.

Biology. Nothing is known of the biology of this uncommon species. The Jalisco specimen was taken at 1700 m in pine/oak forests (Rivera and Garcia 2008).

Remarks. Bates (1888) transferred Gymnetis alboscripta to Cotinis Burmeister. Krajcik (1998) erroneously placed G. alboscripta in both Cotinis and in Gymnetosoma Martínez , and he included G. salicis (Bates) and Amithao distigma Schoch as junior synonyms. This species clearly belongs in the genus Gymnetina because of the traits characterizing this genus. The Jalisco specimen, taken at 1700 m, was erroneously identified as G. cretacea (Rivera and Garcia 2008) , but there was a photograph that confirms its identification.

Figures

Figure 32. Distribution map for Gymnetina species.

Figures 1-4. Gymnetina alboscripta: 1-2) Dorsal and ventral views, respectively. 3-4) Dorsal and ventral views, respectively, of parameres. Note distinct tooth at base of paramere on ventral side (arrow).

Figures 39-44. Habitats for Gymnetina species: 39) Huachuca Mts., Cochise Co,, AZ. 40) Oak woodland,east slope of Patagonia Mts. near Locheil, Santa Cruz Co., AZ. 41) Just southeast of Oaxaca, Mexico, habitat for Gymnetina alboscripta. 42) Baccharis sarothroides, Santa Cruz, Co., AZ. 43-44) Oak trees and tree holes in which Gymnetina species breed. Carr Canyon, Cochise Co., AZ.

Figures 29-31. Gymnetina salicis, dorsal view. 30-31) Dorsal and ventral views, respectively, of parameres. Note distinct tooth at base of paramere on ventral side (arrow).