A new genus and two new species of arctiine tiger moth (Noctuidae, Arctiinae, Arctiini) from Costa Rica

Leichosila gen. n. is described based on two new species, Leichosila talamanca sp. n. and L. wagneri sp. n., from montane rain forests of Costa Rica. Leichosila is allied to the North American Hyphantria Harris generic group (subtribe Spilosomina) which is largely temperate-subtropical in distribution, suggesting that Leichosila is derived from North American faunal elements rather than Andean/South American.


Introduction
Th e subtribe Spilosomina is a relatively small group in the New World, with 10 North American genera (Schmidt and Opler 2008) and approximately twelve more described and undescribed strictly Neotropical genera, excluding misplaced genera (Schmidt, in prep.). By comparison, more than 60 genera occur in the eastern hemisphere (Kôda 1988;Goodger and Watson 1995;Dubatolov 2006), with the greatest diversity in the Oriental and Afrotropical regions. Spilosomina has previously been treated either as a tribe (here ranked as a subtribe following the changes proposed by Lafontaine and Fibiger 2006), or considered synonymous with a broader concept of the Arctiina (e.g. Arctiini sensu Franclemont 1983;Watson and Goodger 1986). Although a phylogeny of the Arctiina sensu lato with broader taxon-and character sampling is still needed, a preliminary phylogeny of the Arctiina (s.l.) (Schmidt 2007) shows that the Spilosomina are well supported as a monophyletic group.
Th e genus-level diversity of North American spilosomines is greatest in Mexico, where representatives of all genera occur, with the exception of Phragmatobia Stephens (northern boreo-cordilleran), Caribarctia Ferguson (Hispaniolan) and Seirarctia Packard (Eastern North American). Th is suggests that the mid-latitude Americas are a possible centre of origin for many North American spilosomines, consistent with the fact that North American species associated Spilosoma Curtis are a paraphyletic group of species, none congeneric with Eurasian Spilosoma (sensu stricto) (Schmidt, in prep.).
As a rule, spilosomines feed on low-growing herbaceous plants as larvae (Wagner 2005), and are accordingly most common in non-forest habitats, typically xeric woodland, savannah, grasslands and wetlands. Hyphantria cunea (Drury) is the only known exception to this herb-feeding habit, and is exceedingly polyphagous on deciduous trees and shrubs (Wagner 2005). Th e discovery of a new genus related to temperate North American spilosomines was therefore surprising given that members of this new genus inhabit tropical forests, and occur much farther south than most other species of the group.

Methods and materials
Adult genitalia were prepared following the methods detailed by Lafontaine (2004). Line drawings were prepared from genitalia suspended in 30 % ethanol, using a camera lucida mounted to a Leica M-165C dissecting microscope. Genitalia were photographed from Euparal-mounted microscope slides using a Nikon D200. Repository abbreviations are as follows:

CNC
Canadian National Collection of Insects, Arachnids, and Nematodes, Ottawa, Ontario, Canada. INBIO Instituto Nacional de Biodiversidad, Santo Domingo de Heredia, Costa Rica.

JBS
Personal collection of J. Bolling Sullivan, Beaufort, North Carolina.

BVC
Personal collection of Benoit Vincent, Saint-Denis, France.

Systematics
Leichosila Schmidt, gen. n. urn:lsid:zoobank.org:act:37F4D9EA-EDF5-4376-B9D3-D41901CBB5A7 Type species. Leichosila talamanca Schmidt, sp. n. Diagnosis. Leichosila can easily be distinguished externally from all other New World arctiines by the unique wing pattern and colour, consisting of a grey to whitish-grey ground colour with a pattern of dark grey-black, incomplete forewing bands that are ochre yellow centrally (Figs 1, 2). Structurally, the following combination of characters is unique: male antennae simple ( Fig. 9), juxta very broad and shallow (5 × wider than long; Fig. 8); male valve lacking medioventral lobe (Figs. 3a, 4a), abdominal markings absent (Figs. 1, 2). Th e juxta shape is a putative autapomorphy of the genus and is unlike that of any other New World spilosomine.
Description. Male (female unknown). Head -Male antenna fi liform in dorsoventral view, ciliate and subserrate ventrally; segment slightly longer than wide (Fig.  9); dorsal antennal scales greyish brown; palpi porrect, 3 rd segment ½ length of 2 nd segment; vestiture of palpi, frons and vertex dusty brown grey; haustellum reduced and poorly sclerotized, presumably non-functional. Th orax -Vestiture of vertex and ventrum of thorax, patagia, tegulae and legs dusty brown grey and shaggy; apex of prothoracic tibia with two subequal, blunt, triangular projections; two meso-and metathoracic tibial spurs, the posterior spur slightly longer than anterior, length of spurs approximately equal to tibial width at apex; metepisternum with rounded ridge along anterior margin, microtymbals absent. Forewing (Figs. 1, 2) -length 13.4 to 16.1 mm; ground colour dark mouse grey to whitish grey; 5 transverse bands of yellowish ochre, outlined in dark charcoal grey; bands evident as fi ve discrete cells along costa, three basal bands obsolete in medio-basal area, and again present along anal margin except for basal-most band; ochre and grey areas of three distal bands confl uent in costal half, with ochre scaling extending along veins; distal band often darkest and most complete; pattern similar ventrally, but colours washed-out. Hindwing (Figs. 1, 2)ground colour dusty grey to whitish grey, with irregular dark-grey subterminal spots and medial spot, these varying in contrast from pronounced to obsolete against darker ground colour; pattern similar ventrally, but colours of subterminal spots washed-out; medial spot darker ventrally than on dorsum, often extending to costa and basally along costal margin. Abdomen -vestiture dusty brown grey dorsally and ventrally; evenly coloured without distinguishable markings (Figs. 1, 2); coremata between 7 th and 8 th sternite absent (Fig. 5); 8 th sternite moderately sclerotized, trapezoidal, 2 × as wide as long (Fig. 5) (Figs. 6, 7); dorsal margin of tegumen recurved caudad, extending to base of uncus; valve consisting of a simple, sickle-shaped, slightly laterally fl attened process (Figs. 3a, 4a) extending dorso-caudally as far as uncus apex (in natural position); valve devoid of processes and lobes (Fig. 3a), or with small sub-basal process on dorsal margin of costa (Fig. 4a); lateral process of transtilla consisting of a poorly delineated, sclerotized region contiguous with membranous area dorso-laterad of anellus, forming shallow, rounded pyramidal prominences directed dorsad; saccus broadly u-shaped, length equalling ¾ height of genital capsule; juxta u-shaped and slightly convex ventro-caudally, very broad and shallow, about 5 × broader than height at midline (Fig. 8); phallus unadorned and relatively stout, approximately 4 × as long as wide (Figs. 3b, 4b); coecum strongly curved ventrad by 90°; vesica globose with four basal diverticula (Fig. 4b), total diameter equalling length of phallus; two diverticula positioned basally and left-laterad, adjacent to each other; two additional diverticula positioned ventro-basally and also adjacent to each other; left half of vesica scobinate, grading to smaller spicules on right side; ductus ejaculatorius positioned right laterad. Etymology. Th e name is feminine in gender, and is derived from the Greek stem for lichen, leichos, and the Latin for yellow ochre, silaceus, refl ecting the odd yellowochre colour of the forewing bands, very unusual for an arctiine. Th is colour pattern is presumably cryptic on lichen-covered trees.
Remarks. Th e caudally recurved dorsal margin of the tegumen and lateral lobes of the 8 th sternite of Leichosila are unique autapomorphies of the Spilosomina (Schmidt 2007). Th e morphology of the male genitalia (valve prong-like and relatively simple, uncus broadly triangular) and wing shape/pattern place Leichosila near the Hyphantria Harris group of genera, consisting of Hyphantria, "Spilosoma" (sensu lato), Alexicles Grote, Estigmene Hübner, and the "Hypercompe" permaculata (Packard) group, although I could fi nd no synapomorphies to suggest a possible sister genus. Th e fi liform antenna and absence of dorsal abdominal markings are rare among all spilosomines, but this condition occurs in some Hypercompe species and Spilosoma vagans (Boisduval), respectively. An incomplete 'barcode' fragment (319 base pairs) of the cox1 mtDNA gene of a single L. talamanca specimen (Barcode of Life Data System; Ratnasingham and Hebert 2007) was approximately equally divergent from species of all Hyphantria-group genera by 5.6 % to 7 %. Th is level of divergence is congruent with the highly autapomorphic morphology of Leichosila, but unfortunately does not provide possible clues to generic relationships to the rest of the group. Th e Hyphantria group is restricted to Central and North America (except for Estigmene albida (Stretch) which occurs south to Colombia), but Leichosila is more closely allied to this group than to Neotropical Paracles Walker and Andean "Phragmatobia" to which Leichosila shows some superfi cial similarities but structurally it is quite diff erent.  Leichosila talamanca Schmidt, sp. n. urn:lsid:zoobank.org:act:7EB77263-5DE4-4AA2-86AE-C02C45C7C0E4 (Figs 1, 3 , 5, 6, 8, 9) Type material. Holotype male -"Costa Rica: Diagnosis. Both Leichosila talamanca and L. wagneri can be easily distinguished from all other New World arctiines by the wing pattern and colour, consisting of a grey to whitish grey ground colour with a pattern of dark grey-black, incomplete forewing bands which are ochre yellow centrally (Figs 1, 2). Leichosila talamanca diff ers from  L. wagneri in its larger size, paler grey colouration of the wings, and internally by the more triangular uncus (parallel-sided in L. wagneri, fi gs 6, 7), lack of a basal process on the costal margin of the valve (Fig.3), and a broadly joined pouch-like diverticulum of the vesica that is pointed and conical in L. wagneri (Figs 3b, 4b).
Description. A detailed description is given above in the generic description. Characters specifi c to L. talamanca are as follows: Male (female unknown). Forewing -length averaging 15.4 mm (14.9-16.1 mm, n = 4); ground colour mouse grey to whitish grey. Hindwing -ground colour mouse grey to whitish grey, with irregular dark-grey subterminal spots, and medial spot. Male genitalia -Uncus triangular in dorsal view; vesica with left diverticulum of two ventro-basal diverticula pouch-shaped and broadly joined to main chamber of vesica (Fig. 3b).
Etymology. Th is species occurs in montane broadleaf forest of the Cordillera de Talamanca, Costa Rica, hence the name.
Distribution and biology. Leichosila talamanca is known only from two localities in the Cordillera de Talamanca. At the type locality, the habitat is dominated by mature oaks (D. Lafontaine, pers. comm Diagnosis. Distinguished from L. talamanca by the smaller size and darker colouration of L. wagneri, and by the genitalic characters given under the diagnosis for L. talamanca. Description. A detailed description is given above in the genus description. Characters specifi c to L. wagneri are as follows: Male (female unknown). Forewing -length 13.4 (n = 1); ground colour dark grey. Hindwing -ground colour dark grey, with indistinct, irregular dark grey subterminal spots and medial spot. Male genitalia -Uncus parallelsided basally, then tapering apically, i.e. bottle-shaped in dorsal profi le (Fig. 7); vesica with left diverticulum of two ventro-basal diverticula conical and pointed (Fig. 4b).
Etymology. Th is species is named after David L. Wagner, who collected the type specimen, and whose studies continue to vastly improve our knowledge of the larval biology of North American Lepidoptera.
Distribution and biology. Leichosila wagneri is known only from the type specimen, collected in high elevation forest (1950-2050 m) on Volcán Barva (Cordillera Central) in mid February.