Chrysina robackeri Hawks 2020, new species
Creators: name: Hawks, David C.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Rutelidae
Chrysina
Chrysina robackeri

description: Chrysina robackeri Hawks, new species
Figures 5–12
Type data. Holotype male (deposited at CNIN), labeled: a) “ MEXICO: Queretaro / Pinal de Amoles / 21°9 ′; −99°39 ′; 2600 m / VIII.2017; local collector”; b) on red paper, “ Chrysina / robackeri male symbol / Hawks, 2020 / HOLOTYPE ”. Paratypes (17M, 6F) labeled as holotype. Paratypes (3M, 1F) labeled as holotype, except “ VII.2017 ”. Paratypes (1M, 1F) labeled: “ Mexico: Queretaro / Pinal de Amoles 2500m / 24 July 2006 D. C. Robacker. Paratypes (1M, 1F) labeled: “ Mexico: Queretaro / Pinal de Amoles / November 2015 / D. B. Thomas. Paratype female labeled: “ Mexico: Queretaro / Pinal de Amoles elev. 8000 ′ / 21 July, 2007 / D. C. Robacker”. Paratype male labeled: “ Mexico; Queretaro, 16-VIII-06 / Pinal de Amoles, El 7943 ′ / N21°07.89 ′; W 99°37.80 ′ Hg-UV / D. Thomas, D. Robacker, J. Burne ”. Paratypes (1M, 1F) labeled: “ MEXICO: Queretaro / Sierra Gorda; 2850m / VII.2013; local collector.” Paratypes (4M, 1F) labeled: “ MEXICO: Queretaro / Pinal de Amoles / 21°9 ′; −99°39 ′; 2600 m / VI.2014; local collector”. Paratypes (2M) labeled: “ MEXICO: Queretaro / Pinal de Amoles / 21°9 ′, −99°39 ′; 2550 m / VII.2016; local coll.”. All paratypes (28M, 10F) with paratype label on yellow paper, “ Chrysina / robackeri male or female symbol / Hawks, 2020 / PARATYPE ”.
Description, holotype male. Length 27.5 mm, width 13.5 mm. Color of dorsal surface of head, pronotal disc, elytra, pygidium yellowish green with darker green reflections; clypeus, pronotum golden pink laterally; apical calli gold (Fig. 5). Ventral surface (Fig. 8) of body and femora darker iridescent green; tibiae internally green; apex of femora, tibiae externally purplish brown with pink and green iridescence; tarsi with weak green iridescence; antennal scape brown with brownish green iridescence dorsally; remainder of antenna brown.
Head. Form overall broad, clypeus subtrapezoidal with truncate, upturned apex; disc slightly tumid in lateral view. Dorsal surface with irregularly spaced small punctures. Clypeus with surface more densely punctate. Anterior border of labrum broadly, shallowly emarginate medially. Mandibles somewhat square, convex; visible in dorsal view. Eye size normal. Ratio of interocular distance to width of pronotum at base = 1: 2.2. Ratio of antennal club length to interocular distance = 1: 1.5.
Thorax. Pronotal basal margin entire. Pronotal surface densely punctate with mixed small and minute punctures. Mesosternal process moderately produced. Each elytron with 9 distinctly impressed, punctate striae; punctures larger than on pronotum; interstriae with only fine punctures not visible without magnification; epipleural fold broad basally, narrowing abruptly in basal third, gradually narrowing after to apex. Venter moderately setose; setae long, light brown.
Abdomen. Pygidium finely, densely rugopunctate; punctures small. Venter glabrous except segments 2–4 with sparse rows of setose punctures; setae much shorter than on thorax. Genitalia: Genital capsule length 9.5 mm. Parameres (Fig. 10–11) almost symmetrical, hastate, notched at apex; recurved in lateral view; ventral keel absent. Ventral plates fused into parabola with rounded apex; emarginate medially.
Male paratype variation (n= 28). Length 26.5–29 mm, width 12.5–15.0 mm. Except for variation in size, male paratypes are very similar to the holotype. Two specimens represent light pinkish-orange (Fig. 6) and darker pink (Fig. 7) color morphs.
Female paratype variation (n = 10). Length 30–35 mm, width 17–20.5 mm. Females (Fig. 9) are nearly identical to males in terms of gross morphological and coloration characteristics, but can be readily distinguished by the last abdominal segment which lacks a membranous apex. As is common in the genus, the female body is slightly more convex in profile, legs and tarsi are relatively smaller, and the antennal club is slightly shorter. The ratio of antennal club length to interocular distance = 1: 2. The inferior genital plates (Fig. 12) are broadly falcate with truncate apices.
Diagnosis. Chrysina robackeri is a member of the Adelaida Group (sensu Hawks 2001), and is most similar to C. difficilis (Morón). In C. robackeri the clypeus is subtrapezoidal and centrally green whereas in C. difficilis the clypeus is trapezoidal and a more solid pinkish-brown color. As compared to C. robackeri, C. difficilis is more densely setose ventrally, more parallel-sided in dorsal view (especially in males), a slightly darker green, and the parameres taper more abruptly. Chrysina robackeri previously was incorrectly identified as C. citlaltepetlamayatli (Blackaller-Bages and Delgado) by Morón and Nogueira (2016). Chrysina citlaltepetlamayatli is more robust and a brighter yellowish-green than both C. robackeri and C. difficilis, and the parameres are more similar to those of C. difficilis. These three species, while clearly related according to morphological and molecular evidence (Hawks, in prep.), are likely completely isolated in their respective high elevation mountainous habitats in eastern Mexico.
Etymology. This new species is named for my friend and colleague, David C. Robacker, who first collected and brought it to my attention. He also has provided me with fresh samples of many Chrysina species, including C. robackeri, for my molecular phylogenetics work. I am grateful to David for his many contributions over a span of more than 20 years to my research on Jewel Scarabs.
description: Published as part of Hawks, David C., 2020, Two new species of Chrysina Kirby (Coleoptera: Scarabaeidae: Rutelinae), pp. 1-6 in Insecta Mundi 2020 (813) on pages 4-6, DOI: 10.5281/zenodo.4565487