Gymnetina salicis (Bates, 1889), 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 : 20-22

Gymnetina salicis (Bates, 1889) , revised combination

( Fig. 29-31 , 32 )

Cotinis salicis Bates 1889: 414 . Original Combination. Lectotype (sex unknown) designated and examined by BCR at RMNH.

Amithao distigma Schoch 1898: 108 . Synonym

Description (males; females remain unknown). Length 19.6-20.4 mm; width across humeri 9.4-12.1 mm. Color of head, pronotum, and pygidium black, shiny. Pronotum along lateral margin with slender, cretaceous band, band occasionally broken ( Fig. 29 ). Mesepimeron and metepisternum black. Elytra reddish brown, shiny, usually with single, small, round to transverse, cretaceous spot on lateral edge of disc behind middle. Pygidium usually with a large, irregularly shaped, cretaceous spot near lateral edge at base on each side. Sternites 1-3 each with small, cretaceous spot on posterolateral margin. Legs and venter black to piceous. Head: Lateral margins weakly elevated. Surface densely punctate; punctures moderate to large, setigerous; setae short, moderate in density, brown. Occiput smooth, shiny. Frons with weak, median, longitudinal keel extending to base of clypeus. Clypeus with apex broadly subtruncate, strongly reflexed, sides distinctly constricted just before antennal insertion. Interocular width equals 4.8- 5.0 transverse eye diameters. Antenna with 10 segments, club slightly shorter than antennomeres 1-7. Pronotum: Surface moderately densely punctate except for disc which is impunctate to sparsely punctate; where dense, punctures mostly large, setigerous (when not abraded away); disc with minute to small punctures; setae short, brown. Mesepimeron dorsally and on anterior face with sparse to dense, mostly large, setigerous punctures; setae brown, short. Elytra: Surface punctate; punctures round, moderately large, glabrous, sparse near suture and becoming progressively denser towards lateral margin where usually rugose. Apical umbone pronounced. Apices nearly right angled to subacutely produced. Pygidium: Surface concentrically rugulopunctate, setigerous; setae moderate in density, minute to short, brown. In lateral view, surface nearly flat in basal half, weakly convex in apical half. Venter: Setae black. Mesometasternal process flat on ventral surface, apex broadly rounded, anterior face nearly parallel (slightly oblique) to longitudinal axis of body. Abdominal sternites each moderately to densely punctate along lateral margin; punctures mostly large with brown to tawny setae. Legs: Femora and meso- and metatibiae with dense fringe of brown to tawny setae. Protibia tridentate, 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. 30-31 ).

Distribution ( Fig. 32 ). This rare species is known only from central Mexico, and the lectotype was collected near Mexico City. 11 specimens examined from CASC, MAMC, OSUC, RMNH, USNM, ZMHU, ZSMC.

MEXICO (11). DISTRITO FEDERAL (2): Mexico City. DURANGO (2): Durango (26 mi. W), Reserva

Biosfera La Michilia. NO DATA (7).

Temporal Distribution. June (1), July (2), December (2). Too few specimens have label data with the month of collection to indicate a reliable temporal distribution.

Diagnosis. Gymnetina salicis is similar to G. borealis in size and in its reduced cretaceous markings but may be separated immediately from that species by its cretaceous pygidial spots and longer, narrower parameres, whereas the pygidium in G. borealis lacks cretaceous spots and has comparatively stout parameres.

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

Biology. Nothing is known of the life history for G. salicis . Bates (1889) indicated the type was found in decayed willow trees, and G. cretacea cretacea , G. cretacea sundbergi , and G. howdeni have also been found in tree holes ( Fig. 43-44 ). Females remain unknown to us.

Nomenclature. Ratcliffe (2004) designated the male specimen in the Leiden museum (RMNH) as a lectotype even though there were some slight discrepancies between Bates’ description in the Biologia and that specimen. Bates indicated the specimen he described was uniformly shiny black, with a strigulose pygidium, 20 mm in length, and a male. The specimen designated is shiny black with reddish brown elytra, is missing the entire abdomen (with a cotton plug instead), and is also 20 mm in length. In his description, Bates did not state whether he had a single specimen or more, although he listed only one male specimen from near Mexico City (the same data as on the lectotype). One of the labels on the Leiden specimen does say “co-type.” Ratcliffe (2004) did not find other syntypes of Cotinis salicis at London or Paris where most of the Bates material resides. In view of all of the above, Ratcliffe thought best to fix the name by designating the Leiden specimen as the lectotype since other specimens in a putative type series were not located.

Schürhoff (1934) placed Amithao distigma Schoch in synonymy with Cotinis salicis and stated C. salicis actually belonged in the genus Gymnetina . Blackwelder (1944), Blackwelder and Arnett (1974), and Goodrich (1966), apparently unaware of Schürhoff (1934), all listed G. salicis as a junior synonym of Gymnetis alboscripta , but these are two different species. Accordingly, we here revise the most recent combination by moving this species once again to Gymnetina . The photograph of “ Gymnetina cretacea ” from Suchil, Durango in Morón et al. (1997) is actually of a specimen of G. salicis .

Figures

Figure 32. Distribution map for Gymnetina species.

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).

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.