Introduction

With 359 described species, the genus Cyclocephala Dejean, 1821 is the largest genus of the tribe Cyclocephalini (Melolonthidae: Dynastinae), widely distributed in the Americas, from southeastern Canada to Argentina (^{Moore et al., 2018b}). The genus has its greatest richness in the Neotropics, especially in Northern South America (^{Ratcliffe, 1992}; ²⁰⁰⁹; ^{Ratcliffe et al., 2015}; ^{Neita-Moreno, 2021}; ^{Paz et al., 2022}). This genus can be recognized among other members of Cyclocephalini by the shape of the clypeus, which it may be rounded, parabolic, subtruncate or emarginate, antenna with eight to 10 antennomeres and male protarsus noticeably enlarged, with the median claw larger than the outer (^{Paz et al., 2022}). However, the recognition of this genus among relatives of the tribe is difficult due the number of the species, diversity of forms, colors and its possibly non-monophyly (^{Moore et al., 2018a}).

Many species have been reported as important pollinators, specifically associated with floral host (^{Moore & Jameson, 2013}), but, on the other hand, larvae of some species have been reported as relevant soil pests in some agricultural crops (^{Morón & Aragón, 2003}; ^{Stechauner-Rohringer & Pardo-Locarno, 2010}; ^{Cherman et al., 2014}; ^{Souza et al., 2015}; ^{Lugo-García et al., 2017}).

In Mexico, the genus is represented by 66 species, being Cyclocephala mesophylla Mora-Aguilar & Delgado (2012), Cyclocephala huamilule^{Romero & Morón, 2017} and Cyclocephala marquezi^{Delgado & Mora-Aguilar, 2020} the latest species described for the country (^{Guzmán-Vázquez et al., 2017}; ^{Romero-López & Morón, 2017}; ^{Delgado & Mora-Aguilar, 2020}).

Of these species, 32 named species have been reported from the Oaxaca state, however, none of them is considered endemic for this area in the country (^{Guzmán-Vázquez et al., 2021}).

n the present work, we described the new species Cyclocephala mixteca sp. nov., based on several adult specimens of both sexes, collected by trapping using a black light trap near to maize crop, in a particular area with high rates of soil erosion, deforestation and water scarcity in the country.

Materials and methods

Adults were captured using a black light trap on a maize field before planting seeds. The traps were installed on the Sitio Experimental Mixteca Oaxaqueña, facilities belonging to the Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), located in Santo Domingo Yanhuitlán, Oaxaca state, southeastern Mexico. The objective of utilizing mass trapping was to diagnose the faunistic composition of melolonthid beetles associated with different native maize races, which are used as field experiments to mitigate the main problems of the region such as resistance to diseases and pests, lack of water, etc.

Later, the specimens were sorted, pinned and dissected at the Campo Experimental Valles Centrales INIFAP, located at Santo Domingo Barrio Bajo, Villa de Etla, Oaxaca. After designating types, specimens were photographed using a Color CMOS C-Mount Microscope Camera attached to a Jewelry Gem Zoom Stereo Microscope, with the software AmScope v. 3.1. Photographs at different depths were staked using the software Helicon Focus v. 6.7.1.

Additional material examined for comparison: Cyclocephala lunulata Burmeister, 1847 three males, four females (INIFAP) labeled: MEXICO, Villa de Tututepec, Río Grande, Sitio Experimental Costa Oaxaqueña (17º 59’ 52.8’’ N, 95º 25’ 33.6’’ W), 20/Jun/2022, L. Gálvez-Marroquín et al. colls. Three males and three females (INIFAP), same data as before but with date 24/Jun/2022. Four males and one female (INIFAP), same data as before but with date 27/Jun/2022.

Results and discussion

Cyclocephala mixteca Cruz-López, Osorio-Alcalá,

Gálvez-Marroquín & Ramírez-Ponce, 2022 sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:177619F9-98D3-46FA-BD9E-93ABD4B24CF9

Figures 1-2

Figure 1 Cyclocephala mixteca sp. nov. A) holotype male, B) paratype female, C) male pygidium, D) aedeagus, E) parameres, F) protarsus of the holotype, G) protarsal claw of the holotype. Scale bars: A and B) 5 mm, C) 2 mm, D and F) 1 mm, E and G) 0.5 mm. 

Figure 2 Variation on head and pronotal markings of Cyclocephala mixteca sp. nov., showing the differences between pronotal macules and the intensity of testaceous color of frons. A) holotype, B-D) male paratypes. Scale bars: 3 mm. 

Type locality. Sitio Experimental Mixteca Oaxaqueña, INIFAP (17° 30’ 11.5’’ N, 97° 21’ 09’’ W), Santo Domingo Yanhuitlán municipality, Oaxaca state, Mexico.

Deposit of types. Entomological Collection (IEXA), Instituto de Ecología, A. C. Xalapa, Veracruz, México, and Colección Nacional de Insectos (CNIN), Instituto de Biología, Universidad Nacional Autónoma de México (UNAM).

Type material. Holotype (male IEXA, red label) labeled: MEXICO, Oaxaca, Santo Domingo Yanhuitlán, Sitio Experimental Mixteca Oaxaqueña, INIFAP (17° 30’ 11.5’’ N, 97° 21’ 09’’ W), 05/May/2021, L. Osorio-Alcalá et al. colls. Paratypes: seven males, one female (IEXA), and five males and six females (CNIN) with yellow labels and with the same data as the holotype.

Etymology. Toponymic in reference to the region where this species was collected: Mixteca. Also, Mixteca means “place of clouds” or “people from clouds” in the original Nahuatl language.

Diagnosis. This new species is easily recognized from the others, specially from the most similar species Cyclocephala lunulata Burmeister, 1847 by the following combination of characters: “C. lunulata-type” coloration pattern on the pronotum, surface setose; frons from yellow to testaceous, but never dark; pygidium setose covered with long and scarce setae; parameres rounded apically.

Description. Holotype (IEXA). Male pinned and dissected. Total length: 16 mm. Color light testaceous. Pronotum with three fuscuous macules and with two black spots between them and lateral margins. Elytra with one central irregular macule each one; humeral callus darker (Fig. 1A).

Head. Frons with moderate small punctures, setose; supraocular area and ocular canthus setose. Clypeus rugose, rounded; apex reflexed. Interocular width 3.5 transverse eye diameter. Antenna 10-segmented, club slightly longer than antennomeres 2-7 (Fig. 1A). Pronotum. Surface smooth on disc; small punctures increasing in size and number toward lateral margins. Setal coverture complete and scattered; setae long, decumbent. Posterior margin without bead (Fig. 1A). Elytra. Surface moderate densely punctate; punctures small and shallow. Setigerous surface; setae scattered on base, denser and slightly longer toward apex (Fig. 1A). Pygidium. Surface smooth and setigerous; setae long and dense, especially on apical portion. In lateral view regularly or strongly convex (Fig. 1C). Legs. Protibia tridentate, basal tooth equally separated from the others. Protarsus enlarged, tarsomere 5 large, slightly curved and concave ventrally. Median claw large, sub-equal to tarsomere 5, curved, apex cleft (Fig. 1F, G). Venter. Prosternal process short, rounded and densely covered with long setae. Parameres. Sub-heptagonal shaped in caudal view, with the lateral apices slightly defined. Inner margins suboval-shaped, smooth. Apical apices of parameres rounded, forming an inverse “V” (Fig. 1E). In lateral view, parameres shorter than tectum and basal piece (Fig. 1D).

Female paratype. Length 15 mm. Similar as the holotype, except for that the epipleuron expanded at level of sternites 1-2. Elytra in dorsal view expanded above sternite 2. Pygidium wider than larger, semitriangular-shaped. Protarsomere simple, not enlarged (Fig. 1B). Variation. In size, from 15 to 17 mm, variation on head and pronotum coloration as in figure 2.

Distribution. This species is only known from the type locality.

Taxonomic comments. Comparisons with C. lunulata. According with ^{Ratcliffe et al. (2013)}, C. lunulata has a very wide geographical distribution along North and Central America, but is easily recognized from other lunulata-type species presents on Mesoamerica, by always shows a black frons, with a variable coloration from piceous or fuscous marks. On the other hand, Cyclocephala mixteca sp. nov. do not have black frons, but its color varies from yellow to testaceous, and pronotum of C. lunulata is glabrous, instead of setose on C. mixteca sp. nov. Also, ^{Maes & Ratcliffe (2018)} mentioned that protarsomere 5 of C. lunulata is shorter than tarsomeres 1-4, while this tarsomere is noticeably longer in C. mixteca sp. nov., and the swelling in the middle of elytron of females of C. lunulata has pillow-like shape, instead flattened in C. mixteca sp. nov. Parameres between these two species are also similar, but according to ^{Ratcliffe et al. (2013)} and ^{López-García et al. (2015)}, caudal view of the parameres of C. lunulata have an oval shape, with the inner margins pointed dorsally. Apices of parameres of C. lunulata are pointing to the inner part, instead rounded on C. mixteca sp. nov. Finally, the basal piece is noticeably longer in the new species described here.