A new Zanclognatha from eastern North America and a preliminary key to the larvae of the genus (Lepidoptera, Erebidae, Herminiinae)

Abstract The adult of a widespread but previously undescribed species of Zanclognatha Lederer is described from eastern North America. Images of the mature larva and life history datafor Zanclognatha dentata sp. n. are included, along with a preliminary key to the larvae of ten eastern North American Zanclognatha species.


Introduction
More than a dozen species of Zanclognatha Lederer, 1857 occur in eastern North America, often with six or more species flying at a single location. Alpha diversity and abundance of Zanclognatha tend to be highest in mixed hardwood and conifer woodlands and forests with an accumulation of leaf litter. The Nearctic Zanclognatha fauna bears earmarks of a recent radiation: several species are weakly differentiated or confused (e.g., Z. gypsalis-minoralis-theralis complex; genitalic diversity across the genus is modest in both sexes; and some species-level taxa occur mainly north of recent glacial maxima, e.g., Z. lutalba (Smith, 1906). In addition to the new species described here, which has long been confused with Z. protumnusalis (Walker, 1859), additional eastern Zanclognatha await recognition, e.g., the undescribed species near Z. lituralis (Hübner, 1818) mentioned by Rings et al. (1992).
The most recent revisionary study of Zanclognatha and its relatives is that of Owada (1987) based on his studies of the diverse Japanese herminiine fauna. In addition to Zanclognatha, his treatment includes all allied genera. Owada recognized both Zanclognatha and Polypogon Schrank (1802) as valid, with the former genus defined by having the labial palpus sickle-shaped and upcurved over the vertex; male antenna with a knot; M2, M3, and CuA1 not stalked in the forewing; hindwing with cell extending to nearly ½ and M2 arising from above the anal angle (of cell); male foreleg with tibial sheath; and male foretarsus five-segmented with first segment lacking a projection. Zanclognatha dentata sp. n., sharing the above features, falls unambiguously within Owada's concept of the genus, despite the fact that the male genitalia of Z. dentata and other Nearctic members of the genus Zanclognatha, superficially resemble those of Polypogon tentacularia (L.), the type of Polypogon, in possessing a deeply emarginate valve with two primary lobes. The type-species of Zanclognatha, Z. lunalis Scopoli, and its Palearctic relatives, have a valve that is comprised of three lobes. Starting with Smith (1895), Lederer's Zanclognatha has been used for the Nearctic herminiines with an antennal knot and upcurved labial palpus. Poole (1989) transferred North American Zanclognatha into Polypogon, but later, moved all species back into Zanclognatha (Poole and Lewis 1996).
The new species was "discovered" while reviewing larval images of Z. protumnusalis and Z. martha Barnes, 1928. Larval images indicated that there were three species involved (see Figs 8-11 and key). Below we describe the adult, provide images of the last instar, and discuss the biology of Z. dentata sp. n. We also include a key to the larvae of ten species of Zanclognatha found in eastern North American.

Methods and materials
A cohort of larvae was reared from a female collected by Dale F. Schweitzer from New Jersey, Atlanta County: Egg Harbor Township, Absecon Creek on 15 July 2002, DLW Lot Number 2002G117. Larvae were reared on dead, browned, lightly moistened oak leaves. Surface as well as partially decayed leaves were provided (see Hohn and Wagner 2000). Specimens were examined from the collections listed below. In addition, several colleagues sent records, images, and observations from personal collections (see acknowledgments). We checked European and Asian literature to ascertain if Z. dentata might represent an Old World species. Larval images (both film and digital) have been deposited at the University of Connecticut. We prepared 29 genitalic dissections of Zanclognatha: 12 of the dentata-martha-protumnusalis group (5 females, 7 males) and 17 dissections of five other species for comparison. In addition we examined 19 Zanclognatha genitalic preparations in Cornell University's insect collection. Martin Honey and Don Lafontaine secured images of the types of Zanclognatha protumnusalis and Z. minimalis Grote in the British Museum.
Type material. Holotype male ( Fig. 1) 1994, 18 June, 1995, 20 June 1999 Etymology. The species name derives from the toothed antemedial and medial lines on the forewing. Diagnosis (habitus). Dark tooth-like spots along costa, marking beginning of antemedial and postmedial lines, distinguish Z. dentata from all but Z. lituralis, Z. martha, and some Z. protumnusalis. The presence of a third (subapical) costal spot, (where the subterminal line meets the costa), usually present in Z. lituralis, is absent in Z. dentata; the grayer ground color and uneven subterminal line also distinguish Z. lituralis from Z. dentata. Z. martha is distinguished from Z. dentata by its darker ground color, weakened subterminal line, darkened distal ¼ of forewing, and its larger size. The discal spot of Z. dentata tends to be larger, more vertically elongate, and the distal side is often more concave than that of Z. protumnusalis and others. The antemedial line of Z. dentata is more toothed (zigzagged) than that of most other similarly-sized, brown North American Zanclognatha (but see discussion). The postmedial line is often abruptly-angled outward over the radial veins in Z. dentata, whereas in Z. protumnusalis and Z. martha, this part of the postmedial tends to be more evenly rounded. In Z. protumnusalis the subterminal line is more likely to be outwardly edged with pale scales (in both wings) and Z. protumnusalis tends to have more tan in the ground color, thinner and crisper costal spots, and lacks the blurry patch of fuscous scales basad of the postmedial line, which extends from the inner margin to the cell, that is present in many Z. dentata. In most specimens of Z. protumnusalis the ground color of the hindwings tends to be noticeably paler than that of the forewings, especially through the radial area.
Diagnosis (genitalia). (Figs 5-7). Male genitalia of Z. dentata differ significantly from those of Z. lituralis -most notably Z. dentata has the upper process of the valve adorned with a small tooth, which is only half as long as the width of the costal lobe, whereas Z. lituralis has a large tooth that is as long as the costal lobe is wide. Z. lituralis has a valve that resists spreading during genitalic preparation and becomes badly skewed if forced. Z. martha resembles Z. dentata but is larger. The spread valves of Z. martha expand to 3.0 mm whereas those of Z. dentata expand to 2.7 mm. Z. dentata male genitalia appear indistinguishable from those of Z. protumnusalis to our eye. Female genitalia have similar internal spinules in the corpus bursa in Z. dentata, Z. lituralis, Z. martha, and Z. protumnusalis, but these extend farther on one side of the bursa in Z. protumnusalis and Z. dentata. In our dissections, length of the female genitalia in Z. dentata is ≥ 6 mm in total length, whereas those of Z. protumnusalis length measure circa 5 mm.
Description. Male. Forewing length: FWL 10.5-13 mm (n=30). Head -pale to deep brown with forward projecting tufts from vertex. Antenna with male androconial notch at 1/3. Labial palpus with third segment 1/2 length of second, with pale scales at apex; second segment with pale scales over mesal surface. Thorax -dorsum concolorous with head. Forewing subtriangular, pale to chocolate brown, and usually well marked. Antemedial line toothed or scalloped; discal spot usually well developed sometimes with distal side concave; postmedial line toothed, thickened where it joins costa; often with diffuse medial patch of dark scales from inner margin to cell; subterminal line straight, sparsely edged outwardly with pale scales. Hindwing brown with weak discal spot and variously-developed postmedial and subterminal lines; the latter generally poorly differentiated to absent. If outwardly edged with pale scales, usually only over anal and cubital areas of wing. Underside of both wings usually with discal spot and well-expressed postmedial line. Procoxa elongate with yellow androconia. Profemur with (concealed) yellow hair pencil from distal end and fan of dark androconial scales from proximal end-both of which usually folded and covered by broad hood of chocolate colored scales from protibiae. Mesothoracic and metathoracic tibiae and tarsomeres lightened apically, appearing banded in dark individuals. Abdomen -Tan to brown with distal edge of each segment pale: abdomen appearing banded in well-marked individuals. Male genitalia (Figs 5,6). Valves (Fig. 5) -Nearly symmetrical; uncus distally expanded compressed laterally, terminating in minute tooth; tegumen as long as valve; valve divided into two lobes for half its length; costal (upper) lobe with short mesal tooth halfway along length; costal lobe terminating in irregular apex crowned with setae, with apices of left and right valves differing in detail; lower lobe unadorned. Aedeagus (Fig. 6) -everted vesica covered with spinules; simple basal lobe; slightly curved mesal lobe; large distal lobe supports very small bulge without spicules. Female genitalia (Fig. 7) -Papillae anales unmodified, short; anterior and posterior apophyses subequal in length; distal half of ductus bursae lightly sclerotized, then heavily sclerotized and ribbed to beyond ductus seminalis; ductus seminalis short and twisted; caudal half of corpus bursae with relatively long, curved, internal spinules; spinules extend past middle of corpus bursae on side opposite ductus seminalis.
Remarks. Dark, boldly-marked individuals are commonly encountered southward. In some, the medial patch of dark scales extends across the wing. Adult phenotypes overlap with those of Z. protumnusalis to the extent that we cannot reliably assign about 15% of light-trapped adults to one species or the other. No diagnostic genitalic characters are known for either sex. COI barcodes for those individuals that we could reliably identify were diagnostic (see below). The holotype was submitted to BOLD for COI barcoding (CNCLEP 81920) and its sequence will be submitted to GenBank. Larval features are also diagnostic (for both species).
Distribution. So far as known, Ontario to Nova Scotia southward through the Great Lake states and in the Appalachians to northern Georgia. One moth from a sandhills area in central South Carolina appears to represent Z. dentata¸ but we exclude the moth from the type series.
Biology. Adults have been taken at lights and sugar bait from a broad range of habitats that includes bogs, swamps, marshes, Atlantic white cedar swamps, swales, and other wetlands, mesic hardwood and Appalachian cove forests, a variety of boreal (conifer) forest types, and pitch pine/scrub oak barrens. The species is essentially univoltine throughout most of its range with a single mid-summer flight from the end of June through early August, with more than 80% of the adults from New Jersey northward taken in July. Records from early September in western North Carolina and northern Georgia by James Adams (pers. comm.) are indicative of a small second brood, as also occurs in Z. protumnusalis and others (Wagner et al. 2011).
Chris Maier, Jeff Fengler, and Carol Lemmon, made numerous collections of Z. dentata during their survey of conifer-feeding caterpillars of the Northeastern United States (Maier et al. 2004). Nine of their larval collections were reared to the adult stage; larval images for four additional collections are assignable to Z. dentata. Their host records include: Abies balsamea (L.) Mill. (n=7), Tsuga canadensis (L.) Carrière (n=3), and Pseudotsuga menziesii (Mirb.) Franco. We have taken singleton larvae in beating sheet samples on three occasions: from Hamamelis virginiana L., Lonicera morrowii A. Gray, and a third, unrecorded host. All of the above were taken in May and June as penultimate or final instars. Although Zanclognatha species are generally regarded to be litter dwellers (Crumb 1956;Hohn and Wagner 2000;Wagner 2005), at least three other members of the genus (in addition to Z. dentata) are known to feed above the ground: Z. theralis (Walker, 1859) in Usnea lichens (Sigal 1984); Z. protumnusalis in fir, spruce, pines, and other conifers (Prentice 1962 and reared specimens in the PMNH); and Z. martha a hard pine associate (Wagner et al. 2011). We also have taken Zanclognatha cruralis (Guenée, 1854) and related species on occasion while beating low woody and herbaceous vegetation in forests, but mostly in the fall, before leaf fall, and not in the spring as has been the case with the four Zanclognatha listed above. Dale Schweitzer and DLW reared an ex ova cohort of Z. dentata through to maturity on a diet of dead oak leaves (DLW Lot 2002G117).

Larval Identification
The caterpillar is mottled in brown, red, and yellow with a conspicuous pale subdorsal spot on A7 (Figs 8-9). Below we expand Crumb's (1956) key to Zanclognatha larvae by including four new taxa: Z. dentata, Z. martha, Z. protumnusalis, and Z. marcidilinea (Grote, 1872). Given the confusing taxonomy of the genus (e.g., the possibility of misidentifications, especially in historic material), our small sample sizes, intraspecific (including ontogenetic) variability in larval phenotypes, our key should be considered preliminary. Development of the middorsal stripe, emphasized by Crumb (1956) and below, is variable. For example, our example of Z. marcidilinea had only a weak line, best expressed over the thoracic segments; conversely Z. cruralis sometime has the remnants of a middorsal line (broken between segments). Last instars of all ten species are figured in Wagner et al. (2011).

Discussion
Zanclognatha dentata is widespread in Northeastern North America. In most collections it is intermixed with Zanclognatha protumnusalis. Less often specimens are sorted with those of Z. lituralis and Z. martha. Surprisingly, given the number of wing scaling characters that distinguish Z. dentata from other Zanclognatha, we did not find male or female genitalic differences that would reliably separate the new species from Z. protumnusalis. As noted above, genitalia are somewhat generalized across the genus (see Forbes 1954: 389 for illustrations of the valve and aedeagus for seven species). As is suggested by the larval key, all of the aforementioned species of Zanclognatha, and others, can be distinguished based on larval characters (see also Crumb 1956). Daniel Handfield had individuals of both Z. protumnusalis (n = 37) and Z. dentata (n = 31) from Quebec sequenced as part of the Bar Codes of Life Data System (http:// www.barcodinglife.org/views/login.php). His Z. dentata (included as paratypes here) clustered in two haplotype groups, remote from those of Z. protumnusalis which clustered in a single group that included several haplotypes. In a larger Zanclognatha data set (n=251) that includes barcodes of all named eastern species, most Z. protumnusalis clustered with Z. cruralis, Z. jaccusalis (Walker, 1859) and Z. obscuripennis (Grote, 1872), whereas Z. dentata haplotypes clustered with Z. martha, Z. theralis (Walker, 1859) (in part) and A. atrilineella (Grote, 1873) (Don Lafontaine in litt.). That the two species were not each other's sisters is hardly surprising given the differences in larval phenotypes of the two: compare figures 8 and 9 with 11 and differences enumerated in the larval key.
The type of Zanclognatha minimalis Grote, 1878, currently regarded as a synonym of Z. protumnusalis (e.g., Franclemont and Todd 1983) (BMNH), is somewhat intermediate in character between Z. dentata and Z. protumnusalis. On the whole Z. minimalis aligns best with the latter, e.g., hindwings of Z. minimalis are too pale to fit comfortably within Z. dentata and the discal spot is small, round and almost free of dark scales. However, two features of the type give us pause: (1) the postmedial line is strongly expressed to the inner margin (it is nearly always vague below the cell in Z. protumnusalis).
(2) Likewise the antemedial line is toothed and well expressed to the inner margin, and thus more reminiscent of Z. dentata.
The New York State Museum has no historical records of Zanclognatha dentata, and TLM did not find this species in Ithaca when he collected there at both light and bait from [1974][1975]. The earliest specimens that we have been able to locate are a series in the American Museum of Natural History from Ocean County, New Jersey taken in 1936. And while the recency of discovery of what is now a widespread and common moth would suggest the species could be an introduction, its presence in northern bogs in Quebec, barrens in New Jersey (in the 1930s), and cove forests in the Great Smokies Mountains are indicative that Z. dentata is a native that escaped the attentions of early lepidopterists.
Zanclognatha is in need of revisionary study. The number of valid species in the gypsalis-theralis-deceptricalis-inconspiculis complex is unknown. Zanclognatha lituralis consists of at least two valid species (Rings et al. 1992). We are uncertain if what is being called Zanclognatha martha in the Great Lakes Region is conspecific with the pitch pine-feeding populations of the Eastern seaboard states. Likewise, Z. protumnusalis (even with Z. dentata removed) may not be a single entity, e.g., specimens from along the Gulf Coast may be nominally distinct. COI barcodes and other (nuclear) molecular data will be needed in many cases, as both genitalia and wing patterns are often of limited utility in the genus. Larvae of Zanclognatha are diverse in character given the modest differences in adult features (Zanclognatha dentata was initially recognized as a distinct entity based on its larva). We encourage others to rear ex ova broods and to preserve and photograph larvae as circumstances permit-most Zanclognatha can be reared on dead oak, cherry, and birch leaves.