Gymnetina cretacea cretacea ( LeConte, 1863 )

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 : 9-11

Gymnetina cretacea cretacea ( LeConte, 1863)

( Fig. 11-14 , 32-34 , 40 )

Gymnetis cretacea LeConte 1863: 80 . Original combination. Holotype at CMNH.

Description. Length 19.0- 26.8 mm; width across humeri 10.0- 14.7 mm. Color black, shiny, with cretaceous marks as follows. Pronotum on lateral margin with broad, cretaceous band, band rarely narrowed. Mesepimeron black along anterior edge, with or without variably sized cretaceous spot along posterior margin. Metepisternum and adjoining part of metasternum completely cretaceous. Elytra each with 2 nearly round cretaceous spots behind middle ( Fig. 11a ), spots rarely reduced to 1 lateral spot ( Fig. 11b ) or connected ( Fig. 11c ). Pygidium with large, subtriangular, cretaceous spot on each side. Sternites 1-4 each with small to mostly large, cretaceous spot on posterolateral margin ( Fig. 12 ). Metacoxa with or without cretaceous spot on posterolateral corner and with or without cretaceous spot on dorsal edge at front. Legs and venter black. Head: Lateral margins strongly elevated. Surface densely punctate; punctures moderate to large, with a few (at most) minute, dark setae between eyes (when not abraded away). Occiput smooth, shiny. Frons with weak (sometimes obsolete), median, keel or longitudinal swelling. Clypeus with apex broadly subtruncate, strongly reflexed (weakly bilobed in anterior view), sides distinctly constricted just before antennal insertion. Interocular width equals 4.5-5.0 transverse eye diameters. Antenna with 10 segments, club in males subequal in length to antennomeres 1-7 in males, females with club slightly longer than antennomeres 2-7. Pronotum: Surface in males with punctures moderate in density and size, females with punctures slightly larger and denser; cretaceous band along lateral margin with sparse, minute, black setae in males, setae slightly longer in females (when not abraded away). Mesepimeron dorsally and on anterior face with mostly dense, large, setigerous punctures; setae short, black. Elytra: Surface punctate; punctures moderately dense, moderately large, many ocellate, glabrous; females usually with punctures denser; sides near lateral margins and apical angles finely rugose. Apical umbone pronounced. Apices subacutely produced. Pygidium: Surface concentrically rugulopunctate, setigerous; setae dense, short, black. In lateral view, profile in males flat except near subapex where convex, nearly entirely flat in females. Venter: Setae black. Mesometasternal process flat on ventral surface, apex narrowly rounded, anterior face oblique at about 45 o to longitudinal axis of body. Abdominal sternites in males each with sparse, small to moderately sized punctures laterally, nearly impunctate at center; females with entire surface moderately punctate, punctures moderate to large. Legs: Protibia slender in males, broader in females, tridentate in both sexes, apical 2 teeth closer to one another than is basal tooth to median tooth; teeth subequally spaced in females. Parameres: In ventral view, base of each paramere lacking small, basally projecting tooth ( Fig. 13-14 ).

Distribution ( Fig. 32 ). Gymnetina cretacea cretacea occurs in southeastern Arizona, southwestern New Mexico, and northern Mexico. The type was described from “Arizona”. 65 specimens examined from ADMC, AMNH, ASUT, BCRC, BMNH, CASC, CMNC, CNCI, CUIC, DNAC, EMEC, FWSC, JPHC, LACM, MCZC, PHSC, RHMC, RLWE, SDMC, SMCC, UAIC, UCRC, USNM, WBWC, ZMHU.

MEXICO (2): SONORA (2): Old Hwy 16 (16.4 mi. NW of Yecora), Rancho Arriba (Highway 2 between Imuris and Cananea).

UNITED STATES (63): ARIZONA (59): Cochise Co. (20): Carr Canyon, Cave Creek Canyon, Chiricahua Mountains, Cochise Stronghold, East Turkey Creek, Fort Huachuca, Miller Canyon, Palmerlee, Portal, Ramsey Canyon, Southwest Research Station (Portal), Texas Canyon, Tombstone, No data. Gila Co. (1): Gila. Pima Co. (10): Box Canyon, Florida Canyon, Greaterville, Kitt Peak, Madera Canyon, Santa Rita Experiment Station. Santa Cruz Co. (25): Duquesne Road (0.8 mi. E Hwy 83), Highway 83 at turnoff to Patagonia Lake, Madera Canyon, Patagonia Mountains (west slope near Sycamore Canyon), Santa Rita Mountains, Sycamore Canyon, Tumacacori Park, No data. No Data (3). NEW MEXICO (4): Hidalgo Co. (4): Godfrey Place (Animas Mountains).

Temporal Distribution. March (1), June (1), July (29), August (31), September (1), October (1).

Diagnosis. Gymnetina cretacea cretacea is distinguished from the similar G. howdeni by punctures at least moderate in density on the pronotum in both sexes (impunctate to sparsely punctate with minute to small punctures in G. howdeni ); the presence of 2, large, round, cretaceous spots on each elytron (rarely fused, Fig. 11c ) instead of a transverse, cretaceous band as in G. howdeni ; by an epimeron with nearly always a cretaceous spot as opposed to a black epimeron (rarely with a cretaceous fleck in G. howdeni ); by the presence of cretaceous spots on the lateral margins of abdominal sternites 2-5 in the males (spots sometimes reduced but never with lateral and submedian, cretaceous spots as normally present in G. howdeni males); parameres more broadly expanded apically and, in ventral view, the base of each paramere lacking a distinct, basally projecting tooth ( Fig. 14 ) that is present in G. howdeni ( Fig. 28 ).

Biology. Gymnetina cretacea cretacea is found primarily in mesquite grassland habitats along the ecotone with Mexican oak woodland habitats ( Fig. 36-40 ), but it occasionally occurs at slightly higher elevations in nearby oak woodland habitats ( Fig. 33-34 ) where G. howdeni predominates. Some specimens have been collected while “gumming” on Baccharis sarorthroides Gray (Asteraceae) along with Euphoria sepulcralis rufina (Gory and Percheron) and Cotinis mutabilis (Gory and Percheron) (F. Skillman, Jr. and D. Ahart, personal observations). Adults, like those of G. cretacea sundbergi , G. howdeni , and G. salicis , have been observed in tree holes ( Fig. 43-44 ) where they presumably breed.

Remarks. This nominate subspecies of G. cretacea and the partially sympatric G. howdeni were previously placed under the single name of G. cretacea . Judging from specimens in collections, Gymnetina cretacea cretacea seems less abundant than G. howdeni .

Casey (1915) described Gymnetina as a subgenus of Gymnetis , with G. cretacea as its only included species. In the older literature, Gymnetina cretacea was placed in the genus Gymnetis ( Leng 1920; Schenkling 1921; Blackwelder and Arnett 1974). Gymnetina was elevated to generic status by Martnez (1949), and the combination of Gymnetina cretacea was subsequently used by Hardy (1975), Deloya and Morón (1997), Krajcik (1998), and Sakai and Nagai (1998). Morón and Deloya (1991) reported this species from La Michilia in Durango, but this specimen is actually G. salicis . Sakai and Nagai (1998) illustrated “ G. cretacea ”, but their figure 1350-1 (Miller Canyon, AZ) is a male of G. howdeni , while their figure 1350-2 (no data) is a female of, possibly, G. borealis , both new species described herein.

Ritcher (1966) placed “ Gymnetis cretacia ” (sic) in a key to the then known larvae of U. S. Cetoniinae, but we have no way of knowing which species he had since there were no adult voucher specimens available for referral. Citing Ritcher (1966), Morón and Ratcliffe (1984) and Micó et al. (2001) placed G. cretacea into keys to the then known larvae of New World Gymnetini .

Figures

Figure 32. Distribution map for Gymnetina species.

Figures 33-38. Habitats for Gymnetina species: 33-34) Madera Canyon, Santa Cruz Co., AZ. 35) Cave Creek Canyon, Cochise Co., AZ. 36-37) Dragoon Mts., Cochise Co., AZ. 38) Patagonia Mts., Santa Cruz Co., AZ.

Figures 11-14. Gymnetina cretacea cretacea: 11a-c) Dorsal views, showing variations of cretaceous pattern on pronotum, mesepimeron, and elytra as well as distinctive punctation on pronotum. 12) Lateral view showing cretaceous metepisternum, pygidial spot, flat mesometasternal process, single row of cretaceous spots on sides of abdomen and distinct concavity of male abdomen. 13-14) Dorsal and ventral views, respectively, of parameres. Note absence of 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 25-28. Gymnetina howdeni: 25a-b) Dorsal views, showing variation of cretaceous pattern on pronotum and elytra as well as sparse, small punctures on pronotal disc. 26) Oblique ventral view showing double row of cretaceous spots on sides of male abdomen, pygidial spot, and more broadly rounded apex of mesometasternal process. 27-28) Dorsal and ventral views, respectively, of parameres. Note distinct tooth at base of paramere on ventral side (arrow).