Thorax. Mainly creamy white with brownish gray and yellowish brown scattered scales. Foreleg mainly brownish gray with creamy white scattered scales. Mid- and hindleg mainly creamy white with brownish gray scattered scales; tibial spurs creamy white. Forewing mainly creamy white with abundant brownish gray and a few yellowish brown scattered scales; poorly differentiated brownish gray transverse stripes broader and darker near costal margin, narrower and lighter towards posterior margin. Hindwing mainly creamy white with poorly differentiated brownish gray transverse stripes near posterior wing margin and brownish gray scattered scales on distal half.
Abdomen. Mainly creamy white with brownish gray and yellowish brown scattered scales. Tergum VIII (Fig. 2) square-like; anterior margin straight, distinctly sclerotized, shortly projected laterally; posterior margin with short semicircular projection in the middle. Tergum VIII (Fig. 2) as two separate longitudinal rods depressed anteriorly, medially curved posteriorly.
Male genitalia (Figs 3–5). Uncus broad, depressed basally, narrow, spine-like distally, with pointed apex. Tegumen narrow, left and right parts completely separated. Saccus broadened ventrally, posterior margin broadly rounded. Juxta as a transverse ellipsoid stripe, calcar broadly U-shaped. Transtilla as a transverse stripe. Labides with anterior arm medially curved, bearing an apical finger like papilla with short setae on distal half; posterior arm straight, bearing a semicircular slightly sclerotized papilla. Valva elongated, broader basally, narrowing distally, apex rounded, costal sclerotized band not reaching apex, sacculus slightly sclerotized. Phallus sub-cylindrical, anterior apex rounded, broadening distally; vesica with two cornuti, larger cornutus a narrow horseshoe-like piece with asymmetrical arms, smaller cornutus a sub-cylindrical piece curved on distal half.
Female. Forewing length similar to male. Antenna with cilia shorter than flagellomere diameter. Wings slightly lighter than those of male, with less brownish gray and more yellowish brown scales.
Female genitalia (Fig. 6). Papilla analis lobe-like, slightly sclerotized near anterior margin, with hair-like setae. Posterior apophysis narrow, rod-shaped, about twice the length of papilla analis. Anterior apophysis narrow, rod-shaped, about half the length of papilla analis; ventral arm about same length as papilla analis, distally depressed and slightly broadened. Antrum broad, membranous. Ductus bursae short, membranous. Corpus bursae mainly membranous, with longitudinal striations, small teeth-like signa grouped in a dense semicircular patch. Ductus seminalis at apex of a narrow, finger-like appendix bursae near the base of corpus bursae.
Etymology. The specific name is derived from the type locality.
Distribution (Fig. 7). Based on the type material, E. copaquillaensis sp. nov. is known only from the type locality, the Copaquilla ravine (18°23'55"S, 69°37'49"W), at about 2800 m elevation on the western slopes of the arid Andes of northern Chile. The high similarity (98.6%) of the barcode of E. copaquillaensis sp. nov. to a congeneric sequence from Antofagasta, Chile found in BOLD suggests a broader geographic range, reaching to about 400 km south of the type locality. However, the exact sampling site of the BOLD sequence is unknown.
Biology. Adults of E. copaquillaensis sp. nov. were collected using a light trap in December 2020. Host plants remain unknown.
Discussion
Eupithecia copaquillaensis sp. nov. is the second species of the genus known to occur in the arid highlands of the western slopes of the Andes of the northernmost part of Chile. The only conspecific previously recorded in the same area is E. tarapaca Rindge, 1987, whose larvae feed on
