Rhyparus chimalapensis Mora-Aguilar & Delgado, 2019

Mora-Aguilar, Eder F. & Delgado, Leonardo, 2019, A new Mexican species of Rhyparus Westwood (Coleoptera: Scarabaeidae: Aphodiinae), with new records and a key to the Mexican and Guatemalan species, Zootaxa 4609 (1), pp. 196-200 : 196-197

Rhyparus chimalapensis Mora-Aguilar & Delgado , new species ( Figs. 1–6 )

Type material. Holotype female labeled: “ MEXICO: Oaxaca, San Miguel Chimalapa, San Antonio, El Retén , El Gringo , VI–VII-2013, 16.6836º N, - 94.2623º W, Alt. 1,600 m, T. intercepción, bosque mesófilo, E. Mora-A y L. Delgado. cols” . Holotype is deposited in IEXA .

Description. Holotype female. Length 3.6 mm, width 1.0 mm. Narrow, elongate, sides parallel; color dark brown, almost black, alutaceous ( Figs. 1–2, 6 ). Head: clypeus with double anterior edge, upper edge with four teeth more-or-less triangular and equally spaced; clypeal margin arcuately emarginate between the teeth; surface of clypeus with scattered, fine punctures separated by one puncture diameter. Disc of frons convex, limited with a distinct narrow furrow from the surrounding surface, with four low obtuse frontal ridges, the middle two separated by about one-third or less the distance to the lateral ridge; surface with shallow, scattered, some setigerous punctures between ridges ( Fig. 3 ). Pronotum: subquadrate; with eight low, evenly spaced, interrupted, and higher posteriorly longitudinal ridges. Apical ridges shorter than flattened bridge; middle pair of ridges obsolete over flattened bridge, uninterrupted to basal margin, almost parallel; each basal ridge with a longitudinal furrow in the inner side; the next pair of ridges completely severed by large and deep transverse deep pits, then continuing to basal margin paralleling the first pair; deep transverse pits narrowly constricted by an oblique projection between second and third ridges. In dorsal view third pair of ridges sinuate with depressions at anterior and basal fourths, basal fourth sinuate, narrow and seemingly forming the posterior pronotal angle opposite elytral humerus; in dorsal view fourth pair of ridges visible as two lateral rounded projections, from the side appearing as a sinuate ridge; basal margin finely carinate with an adjacent line of punctures ( Fig. 4 ). Elytra: subparallel, slightly wider at basal third, longer than wide (1.00: 0.41); costae smooth and shiny, sutural costae slightly elevated, punctate; intervals flat, dull. Base of elytra finely carinate. Costae straight and parallel with a row of separated, very fine, appressed setae along each side; first pair slightly divergent posteriorly; fourth costa curving outward apically and swelling into a large, semitriangular, bulbous, inner apex of bulbous narrowly separated from first costa, and continuing downward in straight angle to join with sutural costa. Apices of three enclosed costae and opposite surface of fourth costae covered with a small light colored mass of glandular material. Intervals with a row of moderately coarse, deep punctures along each side, rows separated by about two puncture diameters, striae slightly crenulate, contiguous to costae, punctures separated in each row by one puncture diameter; apex of first interval flattened ( Figs. 1–2, 5 ). Venter: entire ventral surface feebly shiny but minutely alutaceous. Prosternal processes elevated, anterior half longitudinally carinate, with a shallow depression on each side. Mesostenum microreticulate with minute, close, appressed setae. Metasternum with a single row of six coarse punctures more-or-less parallel to midline furrow. Abdominal segments 2–5 slightly longer at sides, segments 3–5 with a marginal large puncture; median surface of segments with scattered fine punctures bearing very fine, moderately long setae. Pygidium with strong Y-shaped carina separating three depressed areas, the two lateral areas about five times as large as the median basal area, upper ends of carina with their apex swollen and enlarged; apical margin of pygidium roughly punctate ( Fig. 6 ). Legs: profemur with anterior marginal groove, posterior margin slightly arcuate inward, surface covered with moderately coarse punctures. Mesofemur moderately constricted at apical fourth, posterior margin bisinuate, and surface alutaceous with scattered fine punctures. Metafemur flattened, long and slender; surface alutaceous with scattered, fine punctures. Protibia tridentate, two apical teeth rounded. Mesotibiae and metatibiae lacking triangular tooth on apical inner margin, with a small spur directed posteriorly.

Remarks. Rhyparus chimalapensis belongs to the species group with all elytral intervals with two rows of punctures or less, along with R. opacus Cartwright & Woodruff and R. spangleri Cartwright & Woodruff. In the key of Cartwright & Woodruff (1969), R. chimalapensis will key to R. opacus . The new species is distinguished from R. opacus by the following characters: frons with middle ridges separated by one-third of the distance to the lateral ridge (separated by one-half of the distance to the lateral ridge in R. opacus ), pronotum with the two middle basal ridges almost parallel (divergent posteriorly in R. opacus ), second elytral interval with most punctures separated by one puncture diameter on each row (separated by more than one puncture diameter in R. opacus ), and apex of first elytral interval flattened (convex in R. opacus ) ( Figs. 1–9 ). The new species is also distinguished from R. spangleri by the following characters: elytral intervals dull (shiny in R. spangleri ), punctures small and shallow (large and deep in R. spangleri ), and punctures separated by one puncture diameter (less than one puncture diameter in R. spagleri ).

Etymology. The specific epithet is derived from Chimalapas, the region of the state of Oaxaca where this species was collected, combined with the Latin suffix –ensis, meaning belonging to.

Distribution. Rhyparus chimalapensis is only known to occur in the cloud forest of El Retén, in the Chimalapas region, located at the southeastern, Oaxaca, Mexico ( Fig. 10 ). The cloud forests at the type locality and neighboring areas (1,450–1,800 m) are highly conserved but not legally protected areas.

The distribution of Rhyparus chimalapensis is isolated from the remaining Mexican species of this genus, especially from the more similar species R. opacus and R. spangleri . Rhyparus opacus is found northern of the Tehuantepec Isthmus, in the Sierra Madre Oriental of northwestern region of Oaxaca and central Veracruz states ( Fig. 10 ). Rhyparus spangleri is only known for a single male from Turrialba, Costa Rica.

Natural history. The only known specimen collected was caught in a flight intercept trap, located inside a cloud forest.

Figures

FIGURE 10. Geographical distribution of Mexican and Guatemalan species of Rhyparus. Rhyparus chimalapensis (black circle), R. costaricensis (black triangle), R. mexicanus (open triangle), R. opacus (open circle), and R. suspiciosus (open square). Elevational limits each 600 m; darker and punctate lines indicate higher elevation.

FIGURES 1–9. Morphological characters of Rhyparus chimalapensis and R. opacus. Rhyparus chimalapensis holotype female: 1, dorsal habitus; 2, lateral habitus; 3, head; 4, pronotum; 5, elytral apex; 6, ventral habitus. Rhyparus opacus male: 7, dorsal habitus; 8, head; 9, elytral apex.