Onthophagus skelleyi Sánchez, 2018

Sáanchez-Huerta, José Luis, Zunino, Mario & Halffter, Gonzalo, 2018, A New Species of American Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) Associated with Rodent (Geomyidae) Burrows, The Coleopterists Bulletin 72 (3), pp. 407-416 : 408-413

Onthophagus skelleyi Sánchez –Huerta, Zunino, and Halffter, new species

( Figs. 2–5 , 6A, C, E, G , 7A ) Zoobank.org/ urn:lsid:zoobank.org:act:05530198-9E4C-4E62-AE50-7F7A751B9E7B

Description. Holotype. Medium-sized (eutelic) male ( Fig. 3 ): length 11.90 mm; maximum width

6.88 mm, measured slightly in front of caudal edge of pronotal fovea. Dimensions of the other eutelic specimens range in length 11.89– 11.40 mm (n = 4, x = 11.58 mm), maximum width 6.75– 6.29 mm (n = 4, x = 6.56 mm). Color shiny black, uniform, without metallic reflection. Head: Clypeus concave, subpentagonal, transverse, apex slightly sinuate and bordered, strongly punctured, punctation dense and uniformly distributed. Lateral margin of head very slightly sinuate near genal sutures. Genae moderately widened, with greatest width on anterior side. Genal sutures evident, complete, slightly elevated. Clypeal carina entire, with central portion straight, less marked and slightly curved backward on both sides. Frontal carina evident, strongly curved forward at middle, elevated on both sides with 2 horn-shaped tubercles with blunt apex. Anterior surface of carina regularly punctured, punctures gradually smaller towards upper part. Posterior face of carina, including surface of tubercles, with thinly spread punctures, small and almost evanescent. Pronotum: Entirely bordered. Pronotal protuberance strongly developed, triangular, obtuse with blunt apex. Intermediate tubercles absent, posterior tubercles indicated, located slightly in front of cephalic limit of fovea. Surface of disk glabrous, with circular points, large and dense in antero-medially, punctures gradually smaller, increasingly deep and more scattered towards posterior and lateral margins of pronotum. Disk with a faint medial groove, which becomes distinct on posterior fourth. Microsculpture irregular and very superficial, a little less evident towards lateral and posterior regions. Elytra: Striae with poorly defined punctures of medium size; interstriae slightly convex, glabrous, with medium-sized points and gradually smaller towards elytral apex. Punctures poorly defined and irregularly distributed. Microsculpture superficial and irregular, barely visible. Pygidium: Surface densely punctate, punctures transversely elongate and generally poorly defined; punctures confluent at least in basal half, which confers a wrinkled appearance. Microsculpture reticulated and quite evident. Pygidium entirely bordered. Legs: Protibia elongate and slender; internal margin moderately curved at middle and near apex; external margin not serrate between 4 main teeth or on basal margin; apical spur strongly curved inward, apex acute and sickleshaped.

Major Male. Hypertelic ( Fig.2 ). Length 13.00 mm, maximum width 7.66 mm. The major male differs substantially from the eutelic male by the transverse development of the clypeus, strongly produced at right angles laterally, with the anterior margin markedly sinuate at middle; lateral margin of the head emarginate but not incised at the clypeo-genal junction. In addition to the characters described above, the coniform projections of the frontal carina are more developed in the major male, almost reaching the upper side of the pronotum. The pronotal protuberance is stronger, more developed, and triangular, not as blunt as in the eutelic male. The pronotal margin between the anterior and intermediate angles is straighter than that in the eutelic male. The protibiae are proportionally longer in the proximal third. Size of the pronotal punctures is uniform, smaller on the posterior half of the pronotum, scattered, and gradually less marked towards the posterior margin.

Minor Male. Hypotelic ( Fig. 4 ). Length 10.30– 11.21 mm (n = 4, x = 10.69 mm), maximum width 5.75–6.15 mm (n = 4, x = 5.95 mm). The minor male differs from the medium-sized male as follows: reduced development of the clypeus, lateral angles much more obtuse to curved, giving the clypeus a subtrapezoidal appearance, apex almost imperceptibly sinuate; lateral margin of the head slightly curved near the clypeo-genal junction; clypeal carina entire and straight but less evanescent towards both sides; coniform projections of the frontal carina smaller; pronotal prominence triangular, with apex blunt and projecting forward to the anterior margin of the pronotum; anterior and intermediate angles of the pronotum more angulate and defined but not acute; anteromedial region of the pronotal disc with large and dense punctures becoming smaller and gradually more widely spaced towards the posterior and lateral margins, but always distinct, medial groove only slightly evident basally.

Female. Length 10.08–14.1 mm (n = 15, x = 11.98 mm), width 5.34–8.13 mm (n = 15, x = 6.63 mm) ( Fig. 5 ). The female differs from the eutelic male as follows: clypeus transverse and subtrapezoidal, slightly concave and rough in appearance; clypeal carina complete, strong, slightly curved forward and evenly elevated, lower at both sides; clypeal punctures strong and irregularly shaped, poorly defined, dense, uniformly distributed, most punctures elongate and convergent; lateral margins of the head with the clypeo-genal junction almost imperceptible; genal punctures slightly less dense; frontal carina strongly curved forward at middle, forming an inverted U, lateral horn-shaped projections longer and thicker; apex of the pronotal protuberance less developed forward; pygidial punctures poorly defined and notably less elongate; protibiae curved, less elongate and larger, apical spur interno-ventrally projected. The development of the frontal carina is related to body size. We have no evidence of truly major or minor female specimens.

Genitalia. There are noteworthy differences between the aedeagal morphology of O. skelleyi and O. coproides , considered here to be close relatives. In lateral view, the parameres of O. skelleyi are

5) Female habitus.

longer ( Fig. 6a, b ) and their apexes are narrower ( Fig. 6c, d ) on the principal copulatory lamella. The generally reduced development of both the internal and external lobes of the free margin of the left branch of the principal copulatory lamella appear less developed than in O. coproides . There is also a generally reduced development of the folds and carinae of the right branch, apart from the external carina, which is more longitudinally oriented in O. skelleyi ( Fig. 6e, f ). The secondary lamella shows a development with less intricate folds of a relatively simpler appearance, elongated by the effect of the greater development of the part closest to the margin where the lamellar spiny belt is inserted ( Fig. 6g, h , indicated with arrows on both lamellae).

The most evident vaginal differences between O. skelleyi and O. coproides are in the shape of the ventral sclerotization of the vagina. In O. skelleyi , the ventral sclerotization is H-shaped ( Fig. 7a ), with a much narrower central part compared to that which is found in O. coproides ( Fig. 7b ).

Remarks. The hippopotamus complex of Onthophagus currently includes O. coproides , O. hippopotamus , O. halffteri Zunino , O. cuboidalis Bates , O. bassariscus Zunino and Halffter (Zunino and Halffter 1988a; Sánchez-Huerta et al. 2015), and O. skelleyi . On the basis of a comparative analysis of all available information, including morphological and genitalic features, O. skelleyi appears to be closely related to O. coproides . It can be separated from O. coproides by the following combination of external characteristics. Onthophagus skelleyi males have much coarser and deeper head and pronotal punctures than O. coproides males, in which the punctures are fine and shallow. This confers a comparatively more lustrous appearance to the surface of the pronotal disk of O. coproides . The apex of the pronotal protuberance of O. skelleyi is angled, even in small specimens, while it is blunt to slightly curved in O. coproides . The elytral punctation of O. skelleyi is well defined and dense; in O. coproides , it is equally well defined but sparse. In O. skelleyi , the pygidial punctures are pronounced, mostly transversely elongated, and, in some cases, convergent, mainly towards the longitudinal mid-line in both sexes; the microsculpture is comparatively more evident, which gives, together with the punctation, a rough and opaque appearance to the pygidial disc. In O. coproides , the pygidial punctation is fine, with a well delimited circular form, and the microsculpture is poorly evident due to the polished appearance of the pygidium. In all examined specimens, the dorsal coloration of O. skelleyi is bright black without metallic reflections, whereas O. coproides has metallic green reflections on the pronotum, mainly on the dorsum of the pronotal protuberance.

Type Locality. Mexico: Puerto de los Velázquez, Municipality of Pinal de Amoles , State of Querétaro, on the western spurs of the Sierra Gorda , 2,575 m elevation .

Type Material. Holotype: Eutelic male labeled: “ Mexico: Querétaro, Mplty. Pinal de Amoles; ~ 3 air miles W. Pinal de Amoles, 21°07’21’’N, 99°40’17.2’’W 10-13 - DEC - 2013, 2575 m. P. Skelley, P. Kovarik, R. Jones. Orthogeomys mound” ( GHSC) . Paratypes: 3 ƋƋ, 10 ♀♀: “ Mexico: Querétaro, Mplty. Pinal de Amoles; ~ 3 air miles W. Pinal de Amoles, 21°07’21’’N, 99°40’17.2’’W 10- 13 - DEC - 2013, 2575 m. P. Skelley, P. Kovarik, R. Jones. Orthogeomys burrow”. 1 ♀♀: “ Mexico: Querétaro, Mplty. Pinal de Amoles ; ~ 3 air miles W. Pinal de Amoles , 21°07’21’’N, 99°40’17.2’’W 10- 13 - DEC - 2013, 2575 m. P. Skelley, P. Kovarik, R. Jones. Surface dung pitfall ”. 2 ƋƋ, 7 ♀♀: “ Mexico: Querétaro, Mplty. Pinal de Amoles ; ~ 3 air miles W. Pinal de Amoles , 21°07’14.8’’N, 99°40’18.1’’W 12-19 - AUG - 2015, 2575 m. P. Skelley, P. Kovarik. Orthogeomys burrow”. 6 ƋƋ, 4 ♀♀ “ Mexico: Querétaro, Mplty. Pinal de Amoles ; ~ 3 air miles W. Pinal de Amoles , 21°07’11.9’’N, 99°40’14.9’’W 11 - AUG - 2015, 2570 m. J. Luis S. Huerta. Orthogeomys nest” ( GHSC, FSCA, IEXA, JLSHC, MZC) .

Etymology. We have the pleasure of dedicating this species to Dr. Paul E. Skelley (Florida State Collection of Arthropods, Gainesville, FL) in recognition of his outstanding work in the study of the fauna of insects associated with burrows in North America. Dr. Skelley and his colleagues collected most of the material that forms the type series of this new species.

Figures

Figs. 2–5. Onthophagus skelleyi. 2) Major male habitus; 3) Medium male habitus; 4) Minor male habitus;

Fig. 6. Onthophagus species, male genitalia. Aedeagus, lateral view: a) O. skelleyi, b) O. coproides. Parameres, apical view: c) O. skelleyi, d) O. coproides. Copulatory lamella: e) O. skelleyi, f) O. coproides. Accessory lamella: g) O. skelleyi, h) O. coproides. Illustrations of the male O. coproides genitalia were taken and modified from Zunino and Halffter (1988a).

Fig. 7. Onthophagus species, vagina, ventral view: a) O. skelleyi, b) O. coproides. Illustration of the female O. coproides genitalia was taken and modified from Zunino and Halffter (1988a).