Xeropsalta rattrayi, Ewart, 2018

Ewart, A., 2018, Two new genera and five new species of Mugadina - like small grass cicadas (Hemiptera: Cicadidae: Cicadettini) from Central and Eastern Australia: comparative morphology, songs, behaviour and distributions, Zootaxa 4413 (1), pp. 1-56 : 39-40

Xeropsalta rattrayi n. sp.

Figs. 2E – 7E , 8 , 25–27 , Pl. 7A, B.

Types. QUEENSLAND. Holotype male, T244502, Dam, Milroy Hstd, ~ 70 km N. Quilpie, S.W.Q., grass, A.E., I.R., J. N., 15.i.2000; 26°02.856'S 144°20.805'E (QM).

Paratypes. QUEENSLAND: 1♀, Dam, Milroy Hstd, ~ 70 km N. Quilpie, S.W.Q., grass, A.E., I.R., J. N., 15.i.2000 ; 26°02.856'S 144°20.805'E (QM). 38♂, 23♀, Dam, Milroy Hstd, ~ 70 km N. Quilpie, S.W.Q., grass, A.E., I.R., J. N., 15.i.2000, 26°02.856'S 144°20.805'E; 1♂, Barcaldine, C.Q., grassland, 29.i.2009, A.E., 23°33.13'S 145°16.95'E (AE). 1♂, 1♀, Dam, Milroy Hstd, ~ 70 km N. Quilpie, S.W.Q., grass, A.E., I.R., J. N., 15.i.2000, 26°02.856'S 144°20.805'E (ANIC). 1♂, 1♀, Dam, Milroy Hstd, ~ 70 km N. Quilpie, S.W.Q., grass, A.E., I.R., J. N., 15.i.2000, 26°02.856'S 144°20.805'E (MSM). 1♂, 1♀, Dam, Milroy Hstd, ~ 70 km N. Quilpie, S.W.Q., grass, A.E., I.R., J. N., 15.i.2000, 26°02.856'S 144°20.805'E (BMNH).

Distribution ( Fig. 8 ). Known only from the type location, approximately 29 km southwest of Adavale, S.W. Queensland, and near Barcaldine, central Queensland.

Habitat. Open grassland, both known locations close to water, including rivers and standing water. Specimens captured in January, following rains.

Description: Note in the following description that the pristine leaf green colour of the freshly captured insects invariably fades to a yellowish or yellowish-brown hue in set and dried specimens, possibly slightly more so in male specimens.

MALE (Pl. 7A): Head: Supra-antennal plate predominantly leaf green, with two clearly visible black markings along anterior and posterior margins; postclypeus leaf green with two vertical paramedian strips either side of median vertical suture, not extending along transverse ridges, dorsal surface green; vertex and frons green; gena and mandibular plate green, with pale yellowish pubescence; pink to pale brown ocelli; compound eyes dark brown; anteclypeus pale to medium yellowish green; rostrum yellow-green dorsally, distally brown; pedicels and antennae dark brown.

Thorax: Pronotum green to yellow green, slightly darker along lateral fissures; central fascia also yellow green but with thin and discontinuous brown envelope extending along lateral and distal margin, but not anterior margin; pronotal collar and anterior margin green. Mesonotum predominantly yellowish green, submedian sigilla also yellow green, with dark brown along anterior margin and more thinly along inner margins; lateral sigilla with narrow anterior broken dark brown margins, otherwise merges into the main yellowish green area of mesonotum; wing grooves pale yellowish green; metanotum yellow-green; cruciform elevation leaf green.

Wings: Forewing; pterostigma without infuscation; costal vein pale off-white to very pale brown, the remaining venation pale off-white to very pale brown proximally, grading to green distally; basal membrane opaque off-white to very pale brown: hind wing venation off-white to very pale brown proximally, grading to pale green distally; plaga and margins of veins 3A and 2A opaque off-white to very pale brown.

Legs: Predominantly pale yellow-green; femora, tibiae and tarsi with increasing pale brown colouration; claws brown; spines on femora pale yellow-green.

Opercula: uniformly pale yellowish-brown, distal to medial areas near translucent; in outline, rounded but exhibiting marked elongation along axis between crest and disto-medial margin.

Timbals: ribs weakly sclerotised, overall colour pale yellowish-brown; long rib 4 not extending to, and thus not fused with basal spur.

Abdomen and pygofer: Tergite 1 pale yellow to yellow-brown, with narrow darker brown around medial timbal margins; tergite 2 pale yellow-brown, faint and small brownish marking medially, small brown area centrally; auditory capsule mostly green to pale yellow-brown, usually with a thin peripheral deep brown to black colouration; tergites 3 to 7 vary between pale greenish to yellow-brown with medium brown areas across medial region of each tergite (including inter-segmental membranes), weakest on tergite 7; tergites 3 to 5 with moderately small brown areas ventro-laterally, smallest on tergite 5; tergite 8 and pygofer uniformly pale yellowish to yellowbrown; sternites uniformly pale yellowish green, being yellowish-brown on sternite VIII; dark medial area between sternites II and III. Essential genital structures as in generic diagnosis.

FEMALE (Pl. 7B): Supra-antennal plate green, with narrow dark brown strip along contact with postclypeus; remainder of head, postclypeus, mandibular plate, gena, mentum and anticlypeus uniformly leaf green; rostrum pale to darker brown distally; compound eyes dark brown. Pronotum, including central fascia uniformly green to yellowish green; mesonotum uniformly pale green to yellowish green, the submedial sigilla only discernable by the indented marginal rims; fore and hind wings with green venation, tending pale brown proximal to mesonotum; legs almost entirely green, with claws brown and fore tarsi medium brown; tergites and sternites uniformly pale green to greenish-yellow, without darker markings; ovipositor sheath extends 1.3 to 1.7 mm beyond termination of final sternite.

Measurements. N= 11♂ 9♀. Ranges and means (in parentheses), mm; BL: ♂ 12.4–14.5 (13.4); ♀ 12.7–14.2 (13.6). FWL: ♂ 12.8–14.9 (14.1); ♀ 13.3–14.8 (14.1). HW: ♂ 3.2–3.4 (3.3); ♀ 3.2–3.5 (3.3). PW: ♂ 2.9–3.4 (3.2); ♀ 3.2–3.6 (3.3). AW: ♂ 4.3–4.7 (4.5); ♀ 3.8–4.2 (4.0). FWL/WR: ♂ 2.48–2.69 (2.57); ♀ 2.44–2.68 (2.53).

Etymology: Named after Ian Rattray who was instrumental in discovering this species.

Distinguishing the Xeropsalta species ( Figs. 2 to 8). Xeropsalta rattrayi n. sp. males are readily distinguished from males of the other species by their green colouration (or yellow-green in aged specimens). The X. aridula n. sp. and X. rattrayi n. sp. females, however, are superficially similar, but X. rattrayi have narrower tapering abdomens and X. aridula n. sp. narrower fore wings. The females of X. thomsoni are readily distinguished by pale yellow-brown colour and the dark narrow fascia along the dorsal length of abdomen. The morphological and colour separation of the males of X. aridula n. sp. and X. thomsoni n. sp. can sometimes be problematic, although not so for the X. thomsoni n. sp. specimens from the more southerly locations. The abdominal dorsal darker patterns are, however, typically more sharply defined in X. thomsoni n. sp.; the coloration of X. aridula n. sp. is commonly paler than seen on X. thomsoni n. sp.. Figs. 3C–E indicate that opercula shapes do differ slightly, those of X. thomsoni n. sp. slightly less elongated and less domed medially, while Figs. 6C–E and 7C–E indicate small, but possibly significant differences in the profiles of the median lobes of the uncus and in the sizes and shapes of the pygofer basal lobes, as seen in lateral and ventral views. The X. ratttrayi n. sp. males are readily distinguished by the green to yellowish green colour and dark dorsal fascia along tergites. The abdominal colouration of X. festiva n. comb. (Pl. 8) is readily distinguished from the other species of Xeropsalta n. gen. Popple (2014–2017) provides significant additional data on X. festiva n. comb. (previously named Mugadina festiva ). As shown below, the calling song differences of all four species are clearly diagnostic.

Distinguishing the Xeropsalta n. gen. and Heremusina n. gen. species from Dipsopsalta Moulds (2012) . Dipsopsalta was recognised by Moulds (2012, pp. 95–98), only a single species known, namely D. signata (Distant, 1914) , a small cicada found at Cue in Western Australia. Moulds notes that this species is similar to Mugadina , with fore wings veins M and CuA fused as one close to basal cell; fore wing apical cells that are clearly shorter than the ulnar cells; the abdomens of both sexes tending to be approximately cylindrical. It differs from Mugadina in that the male genitalia have an aedeagus that is thick-set, nearly straight and parallel sided, with very short and broad pseudoparameres arising subapically.

Although some of these properties are somewhat similar to those seen in the Heremusina n. gen. and Xeropsalta n. gen. species, differences are present. These include; forewing apical cells that are not all clearly ( Fig. 5 ) shorter than the ulnar cells; the pygofers of Heremusina n. gen. and Xeropsalta n. gen., in ventral views, are not ovoid to sub ovoid as in Dipsopsalta , and have more prominently developed upper pygofer lobes ( Figs. 6 , 7 ); dorsal beaks of the pygofers of Xeropsalta n. gen. and Heremusina n. gen. are more strongly developed ( Fig. 6 ); the claspers of Xeropsalta n. gen. and Heremusina n. gen. are more broadly separated as seen in ventral view ( Fig. 7 ); the aedeagus basal plate in dorsal view is short and broad, apically broadened, far broader than long in Dipsopsalta , clearly contrasting with shapes and forms of the basal plates in Xeropsalta n. gen. and Heremusina n. gen. in which the basal plates are relatively long and apically clearly diverging ( Fig. 7 ).

Figures

FIGURE 3. Male opercula, all left opercula, of the five new species described in this paper; (A), (B), Heremusina udeoecetes n. sp. and H. pipatio n. sp.; (C) to (E), Xeropsalta thomsoni n. sp., X. aridula n. sp., X. rattrayi n. sp., respectively. Opercula nomenclature shown in (E).

FIGURE 5. Right fore and hind wings of the five new species described in this paper; (A), (B), Heremusina.udeoecetes n. sp. and H. pipatio n. sp.; (C) to (E), Xeropsalta thomsoni n. sp., X.aridula n. sp., X.rattrayi n. sp., respectively.

FIGURE 6. Pygofer and male genitalia, lateral views, respectively, of the five new species described in this paper; (A), (B), Heremusina udeoecetes n. sp. and H. pipatio n. sp.; (C) to (E), Xeropsalta thomsoni n. sp. (see also Pl.4), X.aridula n. sp., X. rattrayi n. sp. Pygofer lengths are, respectively, 1.60, 1.70, 1.86, 1.91, and 1.9 mm.

FIGURE 8. Map of Central and Northeastern Australia, showing the currently known occurrences of Heremusina udeoecetes n. sp., H. pipatio n. sp., Xeropsalta thomsoni n. sp., X.aridula n. sp., and X. rattrayi n. sp. The heavy dot-dash line shows the approximate northern and eastern boundaries of the ecoregion which defines the dominance of deserts and xeric shrublands within inland Australia (based on National Reserve System map, published by the Australian Government). The fine dotted lines are major roads, the names of some prominent towns listed. Lake Eyre and associated ephemoral lakes are shown by the darker shading. The approximate outlines of the modern dunefields comprising much of the Simpson and Strzelecki deserts are shown by the lighter shading, these based on 'Google Earth' images.

FIGURE 25. Xeropsalta rattrayi n. sp., all cage recordings: (A), overview waveform showing the repeated and moderately extended echemes, approximately 1–1.5 s in duration, with multiple interspersed short echemes (0.16–0.27 s durations, mean RR 2.5 Hz).A distinctiveproperty of all these echemes is their termination with sharply defined, and relatively abrupt increase in amplitudes. (B), time expanded waveform of a longer echeme (see Fig. 25A for location), illustrating the changing amplitudes, initially low intensity, followed atapproximately 0.3 sec witha marked increase whichextends for about 0.4–0.5s, followed by a decreasing amplitude segment (approximately 0.2 s duration), and the final sharp increase at the echeme termination. (C), a more detailed time expanded segment from the initial 90 ms of the echeme (illustrated in previous Fig. 25 B); this illustrates the initial syllable doublets, these progressively merging into longer macrosyllable with 6 pulses. (D), time expanded view of a complete short echeme (location shown in Fig. 25A), illustrating the extended low amplitude macrosyllables, these initially comprised syllable doublets, which very slowly increase in amplitude and progressively merge, leading at the end of the echeme to the final sharp amplitude 'inflation'.Unfiltered.

FIGURE 26. Xeropsalta rattrayi n. sp. Waveform and companion envelope plots (A, B) of a time expanded segment from the extended echeme shown in Fig. 25B (which shows the precise location within the echeme), and Figs. 25C, D, the time expanded termination of a shortecheme (shown in detail in Fig.25D). Figs, 26A, B illustrate three macrosyllables, each with 6 sets of pulse doublets. The strongest amplitude pulses mark the start of each macrosyllable, these, however, grouped into alternating sets of 3 to 4 pulses (see especially Fig. 26B, the numbers above the pulses indicating the number of pulses in each set). The sets of pulses between the high amplitude sets at the start and end of each macrosyllable also show a tendency for alternation between 4 and 3 pulses, although the pulse structures are somewhat blurred and merged.Fig.26C, D, waveform and envelope plots of the 'inflated' termination of the short echeme as shown in Fig 25 D, with higher amplitude sets of pulses tending to occur at start of each macrosyllable. The pulses between the start and end of each macrosyllables also exhibit an apparent alternation between 4 and 3 pulses. More detailed examination, however, reveals that the '3-pulse' sets do possess weak doublets, themiddle pulses containingthese doubletsclearly of slightlylonger duration (0.6–0.7ms) thanthe otherpulses (0.3–0.5 ms), indicating merging of pulses. The apparent complexity of the pulse structure is, as also seen in X.aridula songs, attributed to the partial and/or complete overlaps between the double pulses. This is seen in the relative lengths of the pulse sets, those with 4 pulse sets of slightly longer durations than the 'apparent' 3-pulse sets. Mean macrosyllable RR's are 117–132 Hz. Unfiltered.

FIGURE 27. Comparisons of Xeropsalta rattrayi n. sp. song in terms of: (A), waveform echeme structures; (B), spectrogram, showing a dominant frequency band between approximately 5–14 kHz, with no frequency variation during song emission; (C), amplitude spectra showing a clearly defined, and relatively narrow dominant frequency envelope between 7.2–10.7 kHz, and inferred dominant frequency of 9.0 kHz.

FIGURE2. Lateralabdomen views of the five new species described in thispaper;(A), (B), Heremusina udeoecetes n. sp.and H. pipatio n. sp.; (C) to (E), Xeropsalta thomsoni n. sp., X. aridula n. sp., X.rattrayi n. sp., respectively.

FIGURE7. Pygofer and male genitalia,ventral views, respectively,of the five new species described in thispaper; (A), (B),H. udeoecetes n. sp. and H.pipatio n. sp.; (C) to (E), X. thomsoni n. sp. (see also Pl. 4), X. aridula n. sp., X. rattrayi n. sp. Sizes as in Fig. 6.