Megatibicen harenosus Cole, 2017, sp. n.

Megatibicen harenosus sp. n.

Fig. 1 A, B, C: male terminalia; Fig. 2: habitus of male (A = dorsal, B = ventral) and female (C = dorsal, D = ventral); Fig. 3 A, B, C: calling song; Fig. 4: distribution

HOLOTYPE: male, U.S.A., NM, Chaves Co., Mescalero Dunes OHV Area, Bureau of Land Management, 39 miles east of Roswell, 33.4077o N, 103.8666o W, 1245 m, 11–12.IX.2009, J.A. Cole leg. PARATYPES: 10 males and 1 female, same data as holotype (SEMK); 4 males, 1 female, same data as above but 26–27.VIII.2015, J.A. Cole, L.A. Gonzalez leg. (LACM); 1 male, U.S. M., NM, Chaves Co., Highway 380, mile marker 194, 10.IX.2005, J. Owens, J. Schmidt leg. (GMCS); 3 males, U.S. M., TX, Ward Co., Monahans Dunes State Park, 31.63581o N, 102.81683o W, 830 m. 25–26.VIII.2015, JA Cole, L.A. Gonzalez leg. (LACM).

Head. Slightly wider than anterior margin and slightly narrower than posterior margin of pronotum. Rostrum tan with black edges in apical one-sixth, extending caudally to posterior margin of metathoracic basisternum. Anteclypeus tan with two spots along central ridge; a black (diffuse in some specimens) spot in center and another in posterior fourth. Postclypeus tan, medial half of transverse grooves infuscated and filled with coarse white hairs that become especially dense laterally. Lora black over posterior three fourths, tan anteriorly. Genae tan. Supraantennal plates tan, with black stripe ventrally from eye to postclypeus. Antennae brown, darker dorsally. Dorsal surface of postclypeus solid black laterally, tan centrally, Frons black with rectangular tan spot anterior to median ocellus. Vertex black with the following areas tan: an elongate anterolaterally trending spot lateral to each lateral ocellus, a central ellipse behind median ocellus, and each posterolateral margin between median ocellus and compound eye, the color in this area obscured by a covering of dense white hairs.

Thorax. Pronotal collar tan except for black central anterior border and slight infuscations anterior to each lateral angle. Within collar tan, with black in the ambient fissures, lateral fissures, and on the entire middorsal pronotal surface between the paramedian fissures, except for a middorsal elliptical tan stripe that extends from anterior margins of pronotal collar to near posterior margin, and adjacent to each paramedian fissure an anterolateral tan spot (holotype) or stripe that may encroach into black of anterior pronotal collar. Fissures filled with pruinosity, especially laterally. Mesonotum with submedian sigilla and lateral sigilla black, and with a tan Wshaped mark centered on the anterior margin with arms that extend around the posterior border of the parapsidial suture posteriorly to the scutellar depressions. Scutellar depressions black, the area between with dense pruinosity that extends anteriorly as a diffuse pruinose stripe to pronotal collar. Heavy pruinose spots extend along anterolateral edges of parapsidial suture, obscuring anterolateral portions of tan W-shaped mark. Lateral sigilla with two narrow to wide oblique tan spots extending anterolaterally, nearly complete in holotype but much reduced in other specimens. Lateral margins of mesonotum with heavy pruinose bands. Scutellum tan, anterior arms of cruciform elevation black apically. Posterior arms of cruciform elevation enclose dense pruinosity laterally. Wing grooves tan, heavily pruinose. Mesothoracic basisternum and katepisternum, and metathoracic basisternum, episternum, and epimeron infuscated with black. Remainder of thoracic venter tan, entire surface heavily pruinose. Pleura tan, heavily pruinose.

Legs. Tan with black stripes on flexor surfaces of forecoxae and infuscations on flexor surfaces of mesocoxae, and with some darker brown striping on extensor surfaces of femora. Spines on forefemora, and spurs and tibial combs on metatibiae dark brown at base, darkening to black at tips. Claws tan at base with black tips.

Wings. Fore wings short, broad, membranes hyaline. Veination tan, darkening to brown apical of node. Crossveins ra2-rp and rp-m1 moderately infuscate. Basal cell tan except posterior one-fourth hyaline. Eight apical cells. Clavus orange. Hind wing veins tan except ambient vein brown. Six apical cells. Plaga white.

Abdomen. Tergites black, III–VII with orange posterior borders that are widest laterally and may thin or disappear towards midline. Timbal covers black. Lateral margins of tergites pruinose as well as the following areas: I with small central spot and heavy lateral spots; II with heavy spot on anterior midline; III with central oblong spot and also long, narrow anterolateral triangles (holotype) or stripes of varying development, extending from lateral margins to four-fifths the distance to midline; IV–VII with small central spots that are faint or absent in some specimens; some specimens also have anterolateral pruinose spots on VI and VII; VIII diffusely pruinose centrally. Pygofer orange with a black square anteriorly on each side of midline, connected posteromedially by a heavy (holotype) to faint V-shaped mark. Sterna orange-tan, with infuscations across anterior half (holotype) that may disappear near midline or be confined to region of hypopleurites, pruinose, especially anteriorly and laterally. Epipleurites infuscated. Sternite VIII tan, pinched and narrowly notched caudally. Opercula tan, lightly pruinose.

Male terminalia. Basal plate with long, slender, dorsally trending digitiform lobes that may be slightly tapering and straight (holotype, Fig. 1 A) or of even width throughout with the tips slightly bent inward (paratype, Fig. 1 C). The lobes connect to the basal plate in a U-shaped ventromedial notch. Stretching between the bases of the lobes just above the heavily sclerotized U-shaped ventromedial notch is a membranous area that may form a roughly Vshaped, obtusely angled notch (Figs. 1 A, C). Uncus triangular, tan (Fig. 1 B). Anal style tan.

Female. Similar in structure and coloration to male except for the following. Head: anteclypeus with single central, diffuse brown spot. Thorax: pronotum with infuscations surrounding lateral and ambient fissures. Abdomen: Tergite II with a pair of dorsolateral pruinose spots confluent with those on tergite I. Tergite VII tan with black anterior border, VIII tan with black lateral infuscations. Sternites infuscated in vicinity of hypopleurites. Sternite VII with a notch along caudal border that is slightly less than 90o, the posterolateral corners rounded, bearing a pair of brown spots.

Measurements. Males (n=13). Body length: 28.95–33.74, 31.20±1.36; fore wing length: 35.22–41.07, 37.66±1.75; fore wing width: 12.77–15.91, 14.30±0.89; head width: 11.32–13.12, 12.150.89; pronotum width: 11.26–13.57, 12.43±0.65; mesonotum width: 9.80–11.95, 10.78±0.64. Females (n=1). Body length: 29.10; fore wing length: 37.62; fore wing width: 14.51; head width: 12.57; pronotum width: 13.15; mesonotum width: 10.80.

Etymology. The sand dune habitat of this cicada is highlighted by the specific epithet harenosus, meaning sandy or full of sand.

Diagnosis. Individuals resemble small M. tremulus in habitus. Both sexes of M. harenosus (Fig. 2 A, C) and M. tremulus (Fig. 2 E) have uniformly pale front wing veins C and R+Sc, and male M. harenosus (Fig. 2 A) and M. tremulus (Fig. 2 E) have black timbal covers. Both color pattern characters distinguish M. harenosus and M. tremulus from M. dorsatus (Fig. 2 F), which has a dark R+Sc vein contrasting with a pale C and brown timbal covers. The coloration of the abdominal dorsum differs between M. harenosus and M. tremulus: in M. harenosus black tergites III–VII are ringed posteriorly with narrow pale bands that widen laterally (Fig. 2 A, C); M. tremulus lacks pale bands (Fig. 2 E) but usually has a reddish tinge on the posterior tergites. In addition, the overall pale body coloration of M. harenosus often has an orange tinge (Fig. 2 A, B) but is tan to brown in M. tremulus, and the wing veins are light tan in M. harenosus (Fig. 2 A, C) and darker tan to brown in M. tremulus (Fig. 2 E).

The shape of the male basal plate of the pygofer and its lobes is diagnostic (Fig. 1; structure misidentified as clasper in Cole 2008). In M. harenosus the basal lobes are digitiform and either slightly tapering from base to apex (holotype, Fig. 1 A) or of even width throughout their length (Fig. 1 C). The medial notch of the basal plate is Ushaped to slightly angulate and at least as wide as one half the length of one of the lobes. In contrast, the basal plate of M. tremulus has a narrow, acute medial notch and conical basal lobes that taper regularly from broad bases to narrowly rounded apices (Fig. 1 D). M. dorsatus has the basal lobes of the pygofer short and square-shaped with blunt apices (not figured; see Figure 1 A in Cole 2008). The lobes in M. dorsatus are separated from one another by a square or narrow U-shaped notch that is subequal to the width of one of the lobes.

Male calling song description and behavioral observations. Megatibicen harenosus is apparently the only Megatibicen species with adult activity in the Mescalero-Monahans dunes during late summer and fall (pers. obs.). During observations at the type locality, males produced calling songs in late morning between 1050–1120 h. Males typically employed sing-fly behavior, in which a given male produced one bout of song from any given location followed by a short flight to a new location for another bout of song. Individual males produced as many as three bouts in a single location, and these bouts were separated by a variable interval of 5 s to 51 s.

Calling song bouts consist of a single brief phrase (19.1± 5.4 s) that is amplitude and frequency modulated (Fig. 3 A-C). Dorsoventral undulation of the abdomen (Cole 2008; Sanborn & Phillips 2004; Stucky 2013) produces alternating high amplitude peaks and a low amplitude troughs (Fig. 3 B). Both peak and trough are of similar duration: 29.1±4.0 ms and 26.4±3.4 ms, respectively. The period of amplitude modulations is 55.2±2.9 ms and the syllable repetition rate is 17.7± 1.0 s -1 (Fig. 3 B). The frequency range of the peak (2.7–14.7 kHz) is broader than that of the trough (2.9–10.4 kHz), and the frequency at maximum amplitude is 5.8±0.5 kHz (Fig. 3 C). The calling song structure of M. harenosus lacks the often prolonged, unmodulated introductory and concluding phrases found in M. tremulus. The fine scale syllable structure also differs (Fig. 3 B–E).

Significant correlations were found between durations of the modulated trough and modulated peak (r = 0.91, p <0.0001), as well as between the duration of the modulated trough and both syllable period (r = 0.67, p = 3.3 × 10-3) and syllable repetition rate (r= -0.73, p = 9.0 × 10-4). Syllable period and syllable repetition rate are mathematically related and were therefore strongly correlated (r = -0.89, p <0.0001). Response variables for MANOVA were thus pared down to three independent characters: duration of the modulated peak, frequency, and syllable repetition rate. Using these three characters as response variables, the null hypothesis that song character means do not differ between M. harenosus and M. tremulus was rejected (p = 4.538 × 10-4). In M. harenosus songs the syllable repetition rate is faster (p = 7.359 × 10-3) with a correspondingly shorter syllable period, and the duration of the high amplitude peaks is longer (p = 4.245 × 10-4) with correspondingly shorter low amplitude trough compared with M. tremulus. Frequency at maximum amplitude did not differ between the two species (p = 6.36 × 10-2). Calling songs of New Mexico and Texas M. harenosus populations were not significantly different (p = 0.221). Example songs will be posted in the BioAcoustica online repository (Natural History Museum, London; www.bio.acoustica.com).

Distribution. Collections were made at the north and south ends of the Mescalero-Monahans shinnery sands ecosystem, thus M. harenosus is likely to occur throughout the dunes. Fig. 4 shows the distribution of all known specimen records (see type data in Species description above) on a map of the dune system.