Achagua magna Matson, 2023

Matson, Tanner A., 2023, The known species of the genus Achagua Rindge, 1983, with the description of three new species from the Neotropics (Geometridae: Ennominae), Zootaxa 5352 (4), pp. 565-576 : 567-571

Achagua magna Matson , n. sp.

( Figs. 2 , 6 , 11 , 12 )

LSID: EBF2D227-50CC-420C-83F7-2939D2F9C3AD

Diagnosis. Achagua magna is most similar to A. obsoleta . While A. magna inhabits the eastern slopes of the central Andes in Ecuador, Peru, and Bolivia, A. obsoleta is thus far only known from the northern Andes in Colombia. Achagua magna (forewing, 21–22 mm) is noticeably larger than A. obsoleta (forewing, 19–20 mm), and though subtle, the pearly-white ground color of the forewing upperside appears to be marked more strongly with intermittent black scaling over the veins; especially in the antemedial and postmedial areas. Achagua magna also appears to bear a more strongly marked, brown to black, terminal area of the hindwing. In males, the lateral margin of the large, subtriangular, anellar processes appears to be less deeply concave in A. magna than in A. obsoleta .

Achagua magna can be distinguished from both A. cooperae and A. velata by the absence of a conspicuous antemedial black spot along the forewing inner margin. Additionally, the male genitalia of A. magna ( Fig. 6 ) bear a spatulate dorsal process of the uncus, a costa with a postmedial digitate protuberance, and a denticulate patch of cornuti on the vesica. In A. cooperae ( Fig. 7 ) and A. velata ( Fig. 8 ), the dorsal process of the uncus is not spatulate or obviously swollen, the costa lacks a postmedial digitate protuberance, and the vesica lacks cornuti. There are other, more subtle differences that can be observed in Figures 6–8 , which further serve to differentiate A. magna from A. cooperae and A. velata .

Description. MALE. Forewing length, 21–22 mm (n = 8).

Head. Antenna mostly bipectinate, but with gradually diminishing rami that are absent in distal quarter of antenna; scales above fuscous, rami ochreous. Vertex mostly white with central gray spot; frons thinly scaled, white. Labial palpus decumbent, 1.5x diameter of eye, and with mixture of white and gray scales on outer surface and white on inner surface. Chaetosemata in transverse row; cephalic collar mostly white with few gray scales.

Thorax. Patagium, tegula, and mesothorax admixture of gray and white scales. Legs mostly white and mottled with gray; epiphysis well-developed; hind tibia with large hair pencil; tibial spur formula 0–2–4.

Forewing. Pearly-white; widely scattered with inconspicuous light gray scales and with intermittent black scaling over parts of veins. Basal, costal, and terminal area of outer margin broadly maculated with brown scales; basal area, apical area, and tornus, more uniformly brown. Underside more uniform pearly-white and without brown basal scaling. Apical area with more diffuse brown scaling than upperside.

Hindwing. Pearly-white except for brown and black terminal band. Underside patterned similar to upperside, but darkened area around outer margin more diffuse and tornal area much whiter.

Abdomen. First segment white with pair of black elongate dorsal spots, second segment black with narrowly triangular white median patch, remainder of abdomen with mixture of white, gray, black, and brown scales; white below. Third sternite of male abdomen with comb of setae.

Genitalia ( Fig. 6 ). Uncus abruptly widened at base; dorsal process thin through middle and apically spatulate; ventral process thumb-like. Base of gnathos subquadrangular, with upcurved, heavily sclerotized, pointed apical projection; apex of projection lightly dentate. Valve large and elongate with heavily sclerotized costa bearing postmedial digitate protuberance. Anellar processes large and subtriangular with elongate, slender posterior projection; lateral margin only slightly concave. Juxta with elongate, medial cylindrical process. Vesica with large denticulate basal patch and weakly sclerotized medial patch.

FEMALE. Unknown.

Type Material.

Holotype

PERU • ♁; Cusco, Quincemil ; elev. 2400 ft; Aug. 1962; L.E. Pena leg.; AMNH _ IZC 00353021 ; AMNH.

Paratypes (8 ♁)

PERU • 5♁; same collection data as holotype; Genitalia: FHR no. 12173, TAM-2023-255, TAM-2023-268; AMNH _ IZC 00353022– AMNH _IZC 00353025, USNMENT01771249; AMNH, USNM • ♁; Cuzco, Cosnipata; (-12.9018°, -71.4117°); elev. 724 m; 28 Aug. 2016; Gunnar Brehm leg.; BOLD Process ID: PEMOA404-16; JPM • ECUADOR • ♁; Zamora Chinchipe; (-3.97388°, -79.084°); elev. 1925 m; 29 Oct. 2002; Nadine Hilt & Claudia Ramenda leg.; BOLD Process ID: NGEOE359-12; JPM • BOLIVIA • ♁; N.P. Carrasco; elev. 900m; (17°06’44”S 65°33’55”W); 05 Oct. 2010; Aare Lindt leg.; Genetic Voucher: TTBO002; TUZ.

Distribution ( Fig. 11 ). Achagua magna inhabits the eastern slopes of the central Andes from the Eastern Cordillera real montane forests of Ecuador south through the Peruvian and Bolivian Yungas.

Biology. Life history information is wanting. Adult records are from August and October.

Etymology. The specific epithet magna is from the Latin “magnus,” meaning “large,” as this species is the largest known member of the genus.

Molecular characterization. This species is represented in BOLD by the BIN: BOLD:ABW8871 (n =3, Peru, Ecuador, Bolivia). Specimens from Bolivia and Peru differ from the only sequenced Ecuadorian individual by about 1.2%. The distance to the nearest neighbor, Achagua cooperae is about 5.9%, however, the presumable sister species of A. magna , A. obsoleta , has not been sequenced.

Remarks. Multi-locus molecular data for this species were used in the phylogenetic studies of Murillo-Ramos et al. (2019) and Brehm et al. (2019). However, the sequenced individual of Achagua was misidentified as A. obsoleta in these studies. This is unsurprising considering the similarity between A. magna and A. obsoleta , and the fact that A. obsoleta was the only described Achagua at that time.

Achagua magna is the name given to the undescribed species mentioned in Rindge (1983). While Rindge initially mentioned his series of A. magna as being from Ecuador in the distribution section of his generic treatment, he later referred to it as being from Peru in the diagnosis and remarks sections of his species’ treatment of A. obsoleta . After examining specimens that Rindge likely studied at the AMNH, where he curated Lepidoptera , there were no specimens from Ecuador, only from Peru. However, during this study, material from Ecuador was later confirmed from other museum collections.

Figures

FIGURE 11. Geographic distribution of Achagua: A. obsoleta Rindge (star), A. magna n. sp. (triangle), A. cooperae n. sp. (circle), and A. velata n. sp. (square). Single dots may represent>1 individual. Scale bar = 600 km.

FIGURE 12. COI neighbor-joining tree generated from all publicly available Achagua sequences. Taxon names followed by BOLD Process ID and country of origin.

FIGURES 1–4. Achagua adult habitus. (a) dorsal view, (b) ventral view. (1) A. obsoleta Rindge, AMNH_IZC 00353009, paratype, (Colombia: Cundinamarca), AMNH; (2) A. magna n. sp., AMNH_IZC 00353021, holotype, (Peru: Cusco), AMNH; (3) A. cooperae n. sp., USNMENT01771270, holotype, (Costa Rica: Alajuela), USNM; (4) A. velata n. sp., holotype, (French Guiana: Régina), MNHN. Scale bar = 2 cm.

FIGURES 5–8. Achagua male genitalia. (a) genital capsule, (b) phallus. (5) A. obsoleta Rindge, TAM-2023-270, AMNH_IZC 00353009, paratype, AMNH; (6) A. magna n. sp., TAM-2023-268, AMNH_IZC 00353023, paratype. AMNH; (7) A. cooperae n. sp., TAM-2023-251,AMNH_IZC 00353028, paratype, AMNH; (8) A. velata n. sp., TAM-2023-289, holotype, MNHN. Scale bar = 2 mm.