Hygrochroma xitle Garzón-Orduña, 2023

Garzón-Orduña, Ivonne J., 2023, A new Hygrochroma Herrich-Schäffer (Geometridae: Ennominae) from Mexico City named by its residents after an ancient volcano, Zootaxa 5318 (4), pp. 594-600 : 595-596

Hygrochroma xitle Garzón-Orduña , new species

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( Figs. 2 , 3 , 4d )

Type material. HOLOTYPE: female. DFW length from base-to-apex: 21 mm. México: Km 55 carretera federal México-Cuernavaca (Morelos), 18-v-1985, Leg. C. Beutelspacher R. Deposited in the CNIN. Dissection code: IGOR 23-25 . PARATYPES: One male and one female. The male is deposited in the CNIN : México, Pedregal de San Angel, C.U. D.F. 6-xi-68, Leg. R . M. Johansen ; dissection code: IGOR 23-26 and the female: México, Ajusco, D.F. 2500 M. 3-iv-1981, Leg. C. Beutelspacher R .; dissection code: IGOR 23-24 will be deposited in the USNM.

Diagnosis. No other described Hygrochroma resembles H. xitle . The species’ color pattern is distinctive, particularly on the ventral surface ( Fig. 4d ), which features two subterminal lines of white scales that cross the forewing and hindwing from the costal margin to almost the anal border but fading before reaching it.

Description. FEMALE. Larger than male (DFW length from base-to-apex: 22 mm, n=2) Head. Frons light brown, almost gray; labial palpus broad and flattened, with second segment pointy. Antenna simple filiform. Haustellum well-developed. Thorax. Covered by elongated scales light brown and white; frenula and retinaculum present; tibial spur formula 0-2-4. Ground color of DFW brown to caramel; costal area striped by thin bands of brown and cream scales. Apex falcate; subapical blotch light brown to gray (faded in holotype). Postmedial area of inner margin with subcircular spot of white to cream scales. Ground color of VFW light brown with silver and brown postmedial and subterminal stripes. Costal margin striped as in dorsal surface; wing apex with notable concentration of white/silver scales; wing veins and cross veins covered with white/silver scales. Abdomen. Covered by contrasting light and dark brown scales and scattered white scales. Genitalia ( Fig. 3a, b ). Anal papillae triangular and covered with hair-like setae; posterior apophysis longer than anterior apophysis. Lamella postvaginalis broad and rugose, lamella antevaginalis flap-like and extended ventrally over ostium bursae ( Fig. 3b ). Antrum broad and elongate; ductus bursae short; rounded corpus bursae with rugose top; signum large hollow dentate disc (3a).

MALE. Smaller than the female (wingspan: 18 mm, n=1), otherwise identical in general habitus. Head. No antenna available; haustellum well-developed; Thorax and Abdomen. As in the female. Genitalia. Tegumen short, uncus elongate and apically tapered ( Fig. 3c, e ). Gnathos with thin lateral arms and medial extension with three or more rows of long spines ( Fig. 3d ); bowed spinulose furca deflected to right (in microscope view) and with elongated cluster of spines ( Fig. 3d ); valve triangular, with costal margin more sclerotized and apex covered by sclerotized setae; aedeagus with digitate posterior extension and vesica armed with group of elongate cornuti ( Fig. 3f ).

Etymology. The name of the species, xitle , makes reference to a monogenetic volcano whose ancient lava makes up the soil under a southern portion of Mexico City named “El Pedregal” and where one of the type specimens was collected. This name was chosen by close to two thousand residents of CDMX and UNAM’s community who were asked to choose among a few alternatives. The name is a noun in apposition.

Remarks. Both H. xitle and H. olivinaria feature a dorsal spot of white to cream scales where the submarginal line reaches the anal margin of the forewing. I am giving H. xitle the Spanish common name polilla caramelo.

Figures

FIGURE 2. Hygrochroma xitle Garzón-Orduña n. sp. HOLOTYPE female (México: Km 55 carretera federal México- Cuernavaca (Morelos), 18-V-1985, Leg C. Beutelspacher R. Deposited in the CNIN. Dissection code: IGOR 23-25.), 2a, adult dorsal habitus; 2b, adult ventral habitus.

FIGURE 3. Female and male genitalia of Hygrochroma xitle. 3a, female genitalia with arrow pointing at the antrum; 3b, lateral view of female sterigma and papillae anales (arrow pointing at lamella antevaginalis); 3c, male genitalia in dorsal view; 3d, medial extension of gnathos and furca (both pointed with arrows); 3e, lateral view of valvae and uncus; 3f. dorsolateral view of aedeagus with arrows pointing at digitate posterior extension and cornuti.

FIGURE 4. Ventral color patterns of Hygrochroma xitle Garzón-Orduña and other Hygrochroma species present in Mexico. 4a, H. bubona (Xalapa, VER. Leg., E.Aranda; 18-vii-82); 4b, H. nondina Druce (Campamento Trepatroncos, San Martín, Berriozabal, CHIS; Leg., IJ Garzón-Orduña, FR Joele, C. Martínez & G. Moreno; 10-12-x-2021); 4c, H. hyalopuncta Dyar (La Esperanza, S. de Juarez, OAX. Leg.A. Ibarra; 18-iv-1983); 4d, H. xitle Garzón-Orduña (Paratype:Ajusco, DF. 2500m. 3-iv-1981 Leg. C. Beutelspacher).