A new species of Scythrididae, Areniscythris whitesands sp. nov. Metzler and Lightfoot, is described from a series of specimens that were found active during the daytime on open bare sand of the white gypsum dunes at White Sands National Monument, Otero Co., New Mexico. Adults and genitalia of the male and female are illustrated, and the bionomy of the species is shortly discussed.
The description of this species is part of a series of papers based on the discoveries of new moth species at White Sands National Monument (White Sands), Otero Co., New Mexico, USA. An arthropod inventory survey of White Sands by Lightfoot resulted in the discovery of a new species of Areniscythris, which is here described.
Jean-François Landry (1991) revised the supraspecific taxa of Nearctic Scythrididae with Areniscythris Powell, a monotypic genus. Powell (1976) described this genus to include a new species, A. brachypteris, collected in 1972 in California coastal dunes. The purpose of this paper is to describe a recently discovered new species of Areniscythris in the white gypsum dunes at White Sands, and it is part of efforts by the authors to detect and provide names for new taxa which occur in White Sands. Taxa described in the scientific literature provide tools, ease, and convenience to the National Park Service in administering, managing, and promoting the appropriate and wise use of its natural resources.
Materials and Methods
A general arthropod inventory survey was conducted at White Sands during the years 2009–2012 by a team of entomologists from the University of New Mexico. Arthropod sampling was conducted throughout White Sands using a variety of arthropod collection methods including light traps, pitfall traps and general collecting, during the daytime and nighttime in the spring, summer and fall seasons. Specimens of Areniscythris were collected during the morning and evening hours in the early summer of 2011 and 2012 on the open gypsum dune crests in association with widely scattered frosted mint (Poliomintha incana (Torr.) A. Gray (Lamiaceae)) shrubs. Specimens collected live in June of 2012 and June 2013 were used for this description.
Genitalia were dissected following procedures outlined in Metzler et al. (2009), except that the dissected parts were dehydrated in 2-Propanol and mounted in Euparal. Terms for morphology and genital structures follow Landry (1991). Photographs of the mounted male and female genitalia were taken with a Nikon™ model D200 camera mounted on the photo tube of a Zeiss® Lumipan Universal Research Microscope using a Leitz 1x plan objective and bright field transmitted light. The camera raw images were processed with Adobe Photoshop® CS6. Measurement for the forewing was made with an ocular micrometer in the eyepiece of a Wild® model M5 stereo-microscope at magnification of 6x.
Identification was made by comparing the specimens to published illustrations of adults and genitalia. Jerry A. Powell examined photographs of adults and male genitalia of this new species. Jean-François Landry examined specimens and genitalia of this new species. Powell and Landry agreed with the diagnosis that this is an undescribed species of Areniscythris. Four hind legs, one from each of four specimens of A. whitesands, were removed by Landry in 2012 for subsequent BOLD DNA barcoding at the University of Guelph based Biodiversity Institute of Ontario Barcode of Life Database (BOLD).
Specimens examined in this paper are deposited in the following collections:
MSUC A.J. Cook Arthropod Research Collection, Michigan State University, East Lansing, MI
UNM Museum of Southwestern Biology, The University of New Mexico, Albuquerque, NM
USNM U.S. National Museum of Natural History (Smithsonian Institution), Washington, DC
Areniscythris whitesands Metzler and Lightfoot,
new species
(Figs 1–9)
Diagnosis. Areniscythris whitesands is a small white and pale gray or very pale tan moth without markings on all four wings. Under magnification it appears to have a pale olive green/gray tint on the wings. The forewings of the female of A. whitesands are fully developed; whereas the forewings of females of A. brachypteris are reduced in size, and “leathery in consistency” (Powell 1976). The forewings of A. whitesands are fully engaged in flight; whereas the forewings of A. brachypteris, fluttering during hopping, aid little in flight. The forewing of A. whitesands is without markings; whereas A. brachypteris has three dark blotches which define two white spots between the blotches in the middle of the disk. The hind wings of A. whitesands are fully scaled; whereas the hind wings of A. brachypteris are sparsely scaled. The lateral margins of the eighth tergite of A. whitesands have a protrusion shaped like a shark's fin. The lateral margins of the eighth tergite of A. brachypteris (Fig. 6) have no protrusions. Illustrations of the male and female genitalia of A. brachypteris are clearly delineated in Powell (1976: Fig. 5) and Landry (1991: Fig. 235). In the male genitalia of A. whitesands the left arm of the gnathos is bent twice, dorsally then posteriorally, heavily sclerotized, not widened, and conspicuous while the right arm is angled dorsad, from ventral view shaped like a bow saw with minute saw teeth, from lateral view anvil shaped, and heavily sclerotized. In the male genitalia of A. brachypteris the distal arm of the gnathos is S shaped and down turned; the right arm of the proximal arm of the gnathos is upturned and narrowed apically; the left arm of the proximal arm of the gnathos is spatulate; the right proximal arm of the gnathos is conspicuously narrower than the left proximal arm, slightly narrowed apically and two thirds the length of the left proximal arm of the gnathos In the female genitalia of A. whitesands the posterior part of the 8th sternite of the female of is neither asymmetrical laterally nor sculpted; whereas in A. brachypteris the posterior part of the 8th sternite is divided laterally, with a mesial membrane, and both sides are sculpted asymmetrically.
Description. Adult male (Fig. 1). Head: Front smoothly rounded out, vertex scales appressed, mixed dirty white to pale tan. Labial palpus upturned, length to one third height of front; first segment white, short, with ventral tuft; second segment slightly curved up, dirty white, ventral scales slightly shaggy; third segment erect, apex pointed, dirty white, scales appressed. Haustellum base densely scaled, dirty white. Antenna: basal half with white scales, distal half ventrally naked. Thorax: Dorsum scales appressed, mixed dirty white and pale tan; underside scales appressed, white. Fore-leg scales in femur and tibia appressed, dirty white, apex with two short, stout teeth-like processes dorsally, tarsomeres scales appressed, dirty white and pale tan. Mid-leg scales appressed, dirty white and tan, terminal tibial spurs, tarsomeres scales appressed, tan, darker apically, numerous stout ventral spurs. Hind-leg scales appressed, tan, tibial spurs, two pair, tarsomeres scales appressed, tan, darker apically, numerous stout ventral spurs. Forewing length 5.0–6.7 mm, mean 5.6 mm (n = 14). Upper surface dirty white and tan, costa paler; fringe concolorous, mixed with dark brown hair-like scales at apex; underside dirty white, scales not overlapping towards base, fringe concolorous. Hind wing dirty white, scattered pale tan fringe concolorous, mixed with dark brown hair-like scales at apex. Underside; costal region at base with setiform scales projected outwardly; numerous dirty white scales not overlapping towards base, fringe concolorous. Abdomen: Dorsum dirty white, reflective white scales on each segment, scales appressed; underside dirty white, scales appressed. Eighth sternite (Fig. 6) sclerotized, broadly incurved anteriorly, small laterally directed fin-like extensions. Genitalia (Fig. 3, 4). Tegumen rounded anteriorly, wide from anterior to posterior; tegumen wide, hood-shaped, slightly asymmetrical. Uncus inconspicuous lobate process fused to tegumen. Gnathos bifurcate, base broadly joined U shaped, left process directed dorsad then sharply bent posteriorly, heavily sclerotized, conspicuous; right process directed dorsad, sclerotized, anvil shaped from ventral view, bow saw shaped from lateral view, conspicuous; vinculum broadly U-shaped. Valva densely setose, straight, elongate, paddle-shaped, distal two thirds widened, saccular margin thickened, apex broadly rounded; phallus (Fig. 5) ca. one third length of valva, anterior 0.2x length a thickened irregular collar, then gradually tapering towards apex, terminal one half with parallel suture-like lines, terminal one tenth length bent, phallotreme encircled with numerous fine teeth.
Adult female (Fig. 2). Head and thorax: Essentially as described for male. Forewing length 4.6–5.7 mm, mean 5.3 mm (n = 13). Hind wing frenulum acanthae multiple. Abdomen: Eighth tergite lightly sclerotized, unadorned; eighth sternite lightly sclerotized, unadorned; dorsum, reflective scales more numerous and more conspicuous than in males. Genitalia (Fig. 7): papillae anales membranous, broadly rounded apically, sparsely setose; apophyses posteriores extended beyond anterior margin of abdominal segment VIII; apophyses anteriores = 0.6x length of apophyses posteriores; sterigma membranous, undefined; corpus bursae membranous.
Holotype. Pinned male with 3 labels: USA: NM: Otero Co. White Sands Nat[ional]. Mon[ument]. N 32°47′ 88″ W 106_14′ 32″ 1,221 m 10 June 2012 diurnal D.C. Lightfoot collector; Gypsum dune crests, open sand, scattered Poliomintha incana (Torr.) A. Gray, active in daylight h[ou]rs Interdune Boardwalk Nature Study Area; Areniscythris whitesands Metzler and Lightfoot, Holotype [red handwritten label] (UNM).
Paratypes. 14 ♂, 13 ♀: All are USA: NM: Otero Co., White Sands Monument, N 32°47′ 88″ W 106_14′ 32″ 1,221 m: 10 June 2012 diurnal D.C. Lightfoot collector, Gypsum dune crests, open sand, scattered Poliomintha incana (Torr.) A. Gray, active in daylight h[ou]rs Interdune Boardwalk Nature Study Area 5 ♂, 9 ♀. 9 June 2013 leg. Lightfoot & Metzler Accss # WHSA 00131, Gypsum dune crests, open sand, scattered Poliomintha incana (Torr.) A. Gray, active in daylight h[ou]rs Interdune Boardwalk Nature Study Area. 9 ♂, 4 ♀. Depositories: MSUC, UNM, USNM.
Systematics. This new species is placed in the genus Areniscythris based on comparison of the genitalia and adult behavior with the generic description. The analysis was confirmed by J.-F. Landry.
Etymology. The specific name, a noun in apposition, calls attention to the type locality, White Sands National Monument. It is important to the National Park Service that biota described from their properties be clearly identified with the property. Because of the specialized nature of White Sands, the largest gypsum dunes system on earth, the name we selected is useful to the U. S. National Park Service for promoting, protecting, and managing the resource.
Distribution and biology. Areniscythris whitesands is known from White Sands (Figs. 9–11). The diurnal behavior of A. whitesands involves more controlled flight than the described behavior of A. brachypteris, the type species of the genus (Powell, 1976). The type locality of A. whitesands is consistent with the association of Areniscythris species with open dunes. Differences in behavior between the two described species can be deduced by comparing the original description of A. brachypteris with the adult behavior described in this paper. Efforts to locate larvae of A. whitesands by digging in the sand among roots of Poliomintha incana shrubs were fruitless. The larval host plant is not known. Details of the behavior of the imagoes are discussed below.
Adult behavior. Lightfoot, alone and in the company of Metzler, made several observations of the imagoes in the gypsum dunes. Specimens representing the type series occurred on the tops of gypsum dunes (Figs. 9, 10) in the vicinity of the Interdune Boardwalk, Nature Study Area. The moths were common on the bare open sand of the dune tops, but were not found on the lower dune slopes or on the interdune flats. Two plant species were growing on the dune tops. Approximately 99% of the stems were the perennial shrub Poliomintha incana (Torr.) A. Gray, called hoary rosemary mint locally at White Sands. USDA Plants Database (2012) uses the common name frosted mint for the species. Stems of Yucca elata (Engelm.) Engelm., locally called soaptree yucca, were infrequent at the type locality of A. whitesands.
The adults were active during the morning and evening hours during relatively hot early summer weather, and would fly up off of the sand surface when approached, flying 3–10 m and landing again on the open sand. The moths were difficult to approach; they could apparently see Lightfoot and flew as he approached. Their behavior was very much like tiger beetles (Coleoptera; Carabidae, Cicindelinae; Cicindela spp.), flying short distances and landing on the open bare sand, and flying again when approached. They were difficult to capture because of their elusive behavior. A light aerial insect net was used to capture them by quickly dropping the net over them as they rested on the sand surface (Fig. 8). Like tiger beetles, they were very good at slipping out from under the rim of the net before they could be contained in a vial. Both females and males were accomplished at flight and difficult to capture except when in copula. In the mid-morning hours, ca. 0900, Metzler was able to capture three mated pairs by placing an open vial over them while they immobile on the sand. Mated pairs have additional labels that associate them with their mates.
Several of the moths were observed flying to and from Poliomintha plants and the bare sand. The Poliomintha did have some flowers, but no moths were observed visiting flowers. Adult moths, resting amongst the unopened flower buds on the terminal flowering branches of the plant appeared to exhibit protective resemblance. Several single female and male moths were observed on the sand surface, and female and male moths were observed mating on the sand surface (Fig. 11).
On previous trips to White Sands in 2010 and 2011, the moths were observed in other areas of the dunes, but always on the tops of dunes, behaving as described above, and in association with Poliomintha incana. Areniscythris whitesands probably occurs throughout the White Sands dune system, but appears to be restricted to the gypsum dune crests of the large dune fields where Poliomintha incana occurs. The moths were observed in May and June of different years, but not observed in April, July, August or September. The moths were not seen on visits to the reddish silica dunes 30 km SE of White Sands during the months of May and June.
Discussion
When Jean-François Landry (pers. comm. 2007) became aware of efforts to document Lepidoptera at White Sands, he suggested the possibility that new species of Areniscythris might be present. Lightfoot reported to Metzler about observations of small, white-colored lepidopterans taking flight from the dune surfaces in May and June of 2011, flying short distances and landing again on open sand during the daytime hours. Lightfoot subsequently collected a series of specimens in June of 2012, and Lightfoot and Metzler collected more specimens in June of 2013.
Areniscythris whitesands appears to be common, but restricted to the gypsum dune crests of White Sands. This species was probably overlooked because of its small size, limited distribution to dune crests, and dearth of research related to insects in White Sands prior to 2007. Areniscythris whitesands was not found among the many nocturnal light trap samples collected in the same areas over the period 2007 through 2011.
Powell (1976) provided several passages about the behavior of A. brachypteris as part of the species account. The contrasting behavior of A. whitesands is provided in the species description.
Figs. 8–11.
Areniscythris whitesands habitat and collecting technique. 8, David Lightfoot kneeling over a net with a captured adult. 9, habitat where type series was collected. 10, aerial photograph of the type locality (image from Google Earth). The sinuous dark line is a 2 lane road. 11, male and female in copulation on the open gypsum sand on a dune crest.
Landry (in litt. 2013) obtained results from the University of Guelph based Biodiversity Institute of Ontario Barcode of Life Database (BOLD) DNA CO1 analysis showing that A. whitesands is 1.15 % dissimilar from another undescribed species of Areniscythris, also collected in New Mexico at La Joya State Game Refuge in Socorro County and at Oasis State Park in Roosevelt Co. BOLD barcode data was obtained from 14 specimens from Socorro and Roosevelt counties. BOLD barcode data was obtained from the legs of four specimens, provided by Metzler, from the type series of A. whitesands. The specimens from Socorro and Roosevelt counties are not white. An examination of the genitalia of the specimens from Socorro and Roosevelt counties was not made. Poliomintha incana does not occur in the dunes at the Socorro Co. site. DNA barcode results have been shown to distinguish numerous species of Lepidoptera (e.g. Burns et al. 2010, Hajibabaei et al. 2006, Hebert et al. 2004, Janzen et al. 2005, & Landry & Hebert 2013) although in some cases they failed to differentiate closely related species of Schinia (Noctuidae) (Pogue et al. 2013). Study of the utility of DNA barcode results pertinent to Areniscythris, and more work on the undescribed species from Socorro and Roosevelt counties, NM, is outside the purpose and scope of our research. Landry will presumably pursue the identity of the Socorro and Roosevelt county species.
Fig. 12.
Areniscythris whitesands distribution map. The black dot is in the Tularosa Basin in Otero County in south central New Mexico.
The species described here joins a growing list of recently discovered species of so called “white species” of moths from White Sands (Metzler et al. 2009, Metzler & Forbes 2011, 2012) (pers. comm. R. W. Hodges 2012, J. D. Lafontaine 2012, J. F. Landry 2012, R. W. Poole 2007, D. J. Wright 2012). White species are those that exhibit white or very pale phenotypes when compared to the same species or closely related species outside the white gypsum dunes.
Genital preparations of Areniscythris whitesands require great care. The structure of the gnathos is not obvious when viewed laterally or ventrally. We found it necessary to remove the gnathos while maintaining proper orientation to the genital structure. The female structure is lightly sclerotized and membranous. The parts cannot be discerned without the aid of light staining to distinguish sclerotization from membrane. Most of the structures are membranous and very difficult to separate, especially when placing the structure in mounting medium on a slide. Genitalic slides of six males and four males were studied.
Acknowledgments
We thank White Sands National Monument staff, especially David Bustos, and the University of New Mexico Museum of Southwestern Biology, Division of Arthropods, for facilitating the project. Jean-François Landry generously provided valuable assistance, and he sponsored the DNA barcoding. Jerry A. Powell confirmed that A. whitesands was, until now, an unknown species of Areniscythris. Huey Lightfoot made personal sacrifices, and Patricia A. Metzler contributed funding to the study. We thank Sangmi Lee for reading an early draft and offering constructive suggestions. Jean-François Landry and Kari Nupponen each offered several comments that improved the paper. Funding for this project was provided by the US National Park Service, Sister Parks Program, Cooperative Agreement contract to Kelly Miller and David Lightfoot, University of New Mexico.
