Flammopenna St Laurent & Herbin 2026, gen. nov.

Flammopenna St Laurent & Herbin gen. nov. Figs 1 a – d, 2 Type species. Flammopenna maya St Laurent and Herbin, sp. nov. by present designation. Diagnosis. Unmistakable among Alheitini or Lacosominae more broadly, appearing more similar to members of Cicinninae, such as Cicinnus Blanchard, 1852 or Aceclostria Vuillot, 1893, than to any other member of its tribe. The subdued, ruddy, earthen tones, poorly delimited antemedial, medial, and submarginal zones, and wavy antemedial and postmedial lines with a faint apical lunule are, in combination, not observed in any other Mimallonidae. Male genitalia are simple, particularly for Alheitini, best defined by the smoothly curving valvae, fist-like gnathos, and narrowly truncate uncus. Below the vinculum the anellus presents a pair of densely setose pads. The phallus is nondescript but very narrow, unlike the typically broad or otherwise highly modified phallus of other Alheitini, especially in comparison with that of its sister genus Arianula Herbin, 2012 (Fig. 1 e – h), which bears a comparatively massive, complex hammerhead-like phallus (Fig. 3 b, d). Likewise, female genitalia are notably simple for an alheitine, with only the setose, bilobed plate of the lamella postvaginalis being a noteworthy character. In both of our genitalia preparations the seemingly extremely fragile and thinly membraned corpus bursae was not recovered. Typically, however, mimallonid corpus bursae rarely contain complex features of diagnostic value and are usually globular or irregularly ovoid and bag-like. Description. Male. Head: frons pale tan-brown to dark brown; eyes very large, occupying more than two-thirds area of head as typical in Mimallonidae, bordered posteriorly by scales slightly darker than anterior margin of thorax; antenna coloration light tan, antenna almost entirely bipectinate, distalmost six or seven antennomers dentate; labial palpus 3 - segmented with third segment very small, hardly noticeable beneath scales. Thorax: coloration red-brown, densely scaled. Legs: coloration as for thorax, vestiture thick. Tibial spurs short, covered in scales except for tip, less than half length of first tarsal segment. Forewing dorsum: forewing length: 14.0–15.0 mm, avg.: 14.7 mm, n = 22. Triangular, deeply concave below apex convex along tornus. Ground color deep red-brown to paler rusty brown, with pale-gray undertone, overall sprinkled with dark-brown spatulate scales, antemedial, medial, and submarginal areas mostly concolorous but with faint gray apical lunule below darkened apex. Antemedial line present, wavy, dark brown; preapical postmedial line dark brown, ranging from well defined to very faint, apical portion may be interrupted or nearly absent. Discal mark present as dark to faint brown mark which may be outlined in gray. Fringe not contrasting with wing. Forewing ventrum: as for dorsum but antemedial line absent, postmedial line wavier than on dorsum, discal spot more well defined. Retinaculum well developed. Hindwing dorsum: coloration, patterning as for forewing dorsum, but antemedial line absent. May be more heavily adorned with spatulate scales. Hindwing ventrum: following same pattern as forewing ventrum. Frenulum present as single bristle. Venation: typical of Mimallonidae (venation preparation not made). Abdomen: dorsal coloration as for thorax. Vestiture thick, long, somewhat denser at terminus. Genitalia: (Fig. 2 a – c) n = 2. Vinculum ovoid, when valvae spread base of vinculum pinches medially. Uncus simple, narrow, truncated distally. Gnathos well sclerotized, fist-like, somewhat flat, medially unfused. Valvae simple, smoothly curving, reaching nearly to apex of uncus. Diaphragm with paired patches of dense setae above phallus. Juxta fused to phallus, ventrally projected to connect to vinculum. Base of phallus weakly sclerotized, with poorly defined coecum phallus. Phallus cylindrical, curved upward distally, vesica simple. Female. Habitus: as for male overall, and within the same range of coloration variation; wings somewhat broader and antennal pectinations shorter, dimorphism very limited, retinaculum absent, frenulum reduced and not visible but presumably as multiple bristles. Forewing length: 17 mm, avg.: 17 mm, n = 4. Female genitalia: (Fig. 2 d, e) n = 2. Tergite VIII narrowest mesally with wider sclerotized regions dorso-laterally. Apophyses anteriores slightly shorter than apophyses posteriores, much thicker, stouter, more curved. Lamella antevaginalis a narrow, sclerotized band, lamella postvaginalis a setose, more lightly sclerotized bilobed plate. Ductus bursae short and membranous, corpus bursae missing from both examined genitalia preparations. Papillae anales broadest mesally, appearing round viewed from terminus, overall densely covered in short setae. Etymology. Flammopenna is a feminine Latin construct of flammeus, meaning fiery red, and penna, feather (wing), referring to the rusty to fiery red wings. Distribution. (Fig. 4) All records for the genus are from Central America, from as far north as Sinaloa, Mexico and on both Pacific and Atlantic coasts of Mexico, southward to northwestern Costa Rica. Records are spotty across this region, and its absence from most natural history collections suggests it is rarely seen (no records before the 1970 s) and likely more widely distributed than our few records would suggest. Natural history. Apart from the habitats inferred from the collecting data reported herein, the only other natural history data available comes from Janzen and Hallwach’s (2017) rearing of this genus in Costa Rica. Based on several records, they report this genus to feed on Diospyros acapulcensis Kunth (Ebenaceae), a rather remarkable host plant for Mimallonidae, which are otherwise not known to feed on this family of plants (St Laurent et al. 2021). Janzen and Hallwach’s (2017) database also has a single record of the new genus from Eugenia acapulcensis Steudel (Myrtaceae) but interestingly we cannot find any other records to support this, and the same specific epithet as Diospyros acapulcensis is used, so it could be in error. Despite this, Myrtaceae is one of the most common host plant families used by Mimallonidae. No photos of the larvae are known. Remarks. While St Laurent et al. (2020) included this genus, unnamed, in their phylogenomic study of all known mimallonid genera, they did not choose to describe it at the time. Flammopenna was recovered with maximum support as sister to Arianula (Figs 1 e – h, 3), a poorly known South American genus that is very dissimilar in external and genitalia morphology. Flammopenna was represented by a particularly long branch in that study, suggesting significant divergence from Arianula. A later study estimated the divergence time between Arianula and Flammopenna (as “ New genus ”) to be approximately 11.6 million years (St Laurent et al. 2021: supplemental fig. 2). Currently, we attribute all specimens of Flammopenna to a single species, formally described below. However, the broad range, lack of continuous records across that range, and minor base pair differences in the mitochondrial “ barcoding ” gene, cytochrome c oxidase subunit I (COI) in publicly available molecular data, are at least suggestive that cryptic diversity exists in this genus (Hebert et al. 2003; Ratnasingham and Hebert 2007). Janzen and Hallwach’s (2017) rearing efforts in Costa Rica provide examples of two barcode clusters (Barcode Index Numbers, “ BINs ”) from the same sites but without morphological differences. Further collecting along its entire range and, ideally, population-level genomics would be useful to best understand the genetic diversity of the genus from Mexico to Central America.