Stamnodes tenebrosa Matson 2023, sp. nov.
Creators: name: Matson, Tanner A.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Lepidoptera
Geometridae
Stamnodes
Stamnodes tenebrosa

description: Stamnodes tenebrosa sp. nov.
urn:lsid:zoobank.org:act: 70D831DE-EBB5-4442-9B83-688D10DECFB4
Figs 35, 38, 89, 95
Diagnosis
Stamnodes tenebrosa sp. nov. is very similar to S. seiferti (Fig. 34), but so far as known the two species are allopatric. Known specimens of S. tenebrosa are from the mountainous Northern Oaxaca Highlands and Oaxaca’s Sierra Madre del Sur, while S. seiferti is a northern Sierra Madre Occidental entity that extends into central Arizona, northern New Mexico, and the Trans-Pecos region of Texas. Stamnodes tenebrosa is darker and slightly larger than S. seiferti, and while sharing many of the same pattern elements, S. tenebrosa can be differentiated by its pale, arcing, medial, transverse band on the darkened hindwing upperside; in S. seiferti, the hindwing upperside is lighter, given toward dull yellow, and lacks a well-differentiated transverse band. Male genitalia are exceedingly close to those of S. seiferti; a notable difference is the rounded laterodistal shoulders of the shield-shaped juxta in S. tenebrosa and more pointed or acuminate shoulders in S. seiferti. Stamnodes tenebrosa also appears to have around 5–6 spinose cornuti while S. seiferti has around 7–8; however, some of the cornuti are increasingly tiny and difficult to visualize and these counts should be considered with caution.
Etymology
The specific epithet tenebrosa, Spanish for ‘dark, gloomy, or murky’, was inspired by this species’ dark wings relative to the much lighter colouration of its apparent sister, S. seiferti.
Material examined
Holotype
MEXICO • ♂; Oaxaca, Mpio. Ixlepejl [Ixtepejl], Cerezal; [17.26° N, 96.56° W]; elev. 2300 m; 7 Nov. 1980; E.C. Welling leg.; genitalia: TAM-2022-097; AMNH _ IZC 00352924.
Paratypes (11 ♂♂)
MEXICO – Oaxaca • 2 ♂♂; same collection data as for holotype; genitalia: TAM-2021-096 (USNM 154203); USNMENT01771242, USNMENT01771243 • 1 ♂; same collection data as for holotype; genitalia: TAM-2021-097; AMNH _ IZC 00353017 • 2 ♂♂; same collection data as for holotype; CNIN • 1 ♂; Mpio. Río Hondo, San José Pacífico; [16.16° N, 96.50° W]; elev. 2400 m; 5 Nov. 1971; E.C. Welling leg.; USNMENT01771244 • 1 ♂; same collection data as for preceding; 21 Nov. 1971; AMNH _ IZC 00352923 • 1 ♂; Mpio. Paxtlán, Agua Azul; [16.21° N, 96.51° W]; elev. 2300 m; 9 Nov. 1977; E.C. Welling leg.; AMNH _ IZC 00352922. – Puebla • 2 ♂♂; 7.5 km NE of Azumbilla; [18.70° N, 97.36° W]; elev. 2200 m; 22 Aug. 1987; Brown and Powell leg.; EMEC1748448, EMEC1748449 • 1 ♂; same collection data as for preceding; CNIN.
Description
Male
FOREWING LENGTH. 18–19 mm (n = 12).
HEAD. Antenna filiform, grey scales above. Vertex and frons mostly grey, white around eyes and base of antennae. Labial palpus slightly porrect, 1.5 × diameter of eye, grey and white. Cephalic collar mostly grey.
THORAX. Patagium grey; tegula grey at base, more fuscous distally. Mesothorax grey to cream. Legs mixture of grey and white scales; tibial spur formula 0–2–4; epiphysis well developed.
FOREWING. Ground colour fuscous, gradually darkening toward outer margin. Costomedial area with subquadrangular, dark fuscous patch terminating near center of wing and outwardly highlighted by U-shaped band of lighter scales. Underside fuscous in basal half, tan and speckled with fuscous scales in distal half; basal and distal areas separated by medial transverse band; band forming near right angle in center of wing that opens toward base. Fringe lighter than fuscous area of outer margin above, concolourous with underside below.
HINDWING. Concolourous with forewing ground colour above, darkening toward outer margin, and bearing pale, arcing, medial transverse band. Underside tan, speckled with fuscous scales, and bearing darkened medial transverse band. Fringe as in forewing.
ABDOMEN. Fuscous to ochreous above, white below.
GENITALIA (Fig. 58). Uncus long, slender, and strongly spatulate at apex. Juxta shield-shaped, posteriorly concave with dozens of erect setae between rounded laterodistal shoulders or protuberances. Valva ear-shaped with costal sclerite terminating in subapical area; inner face of valva with two prominent hair tufts: first tuft arising from large rounded tubercle in antemedial area; second tuft, shorter, linearly extended in costomedial depression. Vesica with 5–6 spinose cornuti greatly decreasing in size in succession.
Female
No material available.
Distribution (Fig. 89)
Mexico: so far as known, Stamnodes tenebrosa sp. nov. inhabits the mountainous Northern Oaxaca Highlands and the Sierra Madre del Sur in Oaxaca and Puebla at elevations around 2200–2400 m.
Biology
Adults fly in November after sympatric S. catarina sp. nov., S. churro sp. nov., and S. patamon. Larvae are predicted to immediately follow the adult flight. Stamnodes seiferti, the presumed sister taxon of Stamnodes tenebrosa sp. nov., has some of the most cold-hardy and latest developing caterpillars in its native range. It would be unsurprising if S. tenebrosa also matures under unusually cold conditions. It is likely that the larvae of S. tenebrosa will feed on Cercocarpus.
Molecular characterization
This species has not been sequenced.
description: Published as part of Matson, Tanner A., 2023, A review of Mexican Stamnodes (Lepidoptera: Geometridae) with the description of 16 new species, pp. 1-79 in European Journal of Taxonomy 911 on pages 65-66, DOI: 10.5852/ejt.2023.911.2371, http://zenodo.org/record/10376790