Rustia minuta, Marathe & Sanborn & Kunte, 2018

Marathe, Kiran, Sanborn, Allen F. & Kunte, Krushnamegh, 2018, Revision of the genus Rustia Stål, 1866 (Hemiptera: Cicadidae: Cicadinae) including a generic synonymy, four new combinations, and two new species from the Western Ghats, India, Zootaxa 4457 (3), pp. 431-443 : 434-437

Rustia minuta n. sp.

( Figures 1–3 , Table 1, Map 1) http://zoobank.org/urn:lsid:zoobank.org:act:7F9E18D0-CCBA-4CD1-AC36-22BC9B78F511

Etymology. The name is in reference to the small body size of the species, minuta (L. little, small).

Type material. Holotype male ( NCBS-QA436 ; Figure 1A–B ); 16.vi.2014; Verlem village in South Goa District , Goa, India (Lat: 15.0491, Long: 74.2766, Map 1); leg. K. Marathe ( NCBS) . Paratypes. – Same data as holotype, six males and five females (NCBS) and two males, NCBS-QA446 and NCBS-QA448 (ZSI-K). A consolidated list of these specimens is in Table 1.

Diagnosis. Rustia minuta n. sp. can easily be distinguished from its congeneric species by its small body length. Rustia minuta n. sp. has the smallest body length (10.4mm for males and 9.8mm for females) reported for a species of Rustia with all other species being larger at least on average, R. dentivitta (female, 16.3mm), R. tigrina (male, 14.3mm), R. marginata n. comb. (male, 16.7mm), R. apicata n. comb. (male, 15.0mm), R. maculata n. comb. (male, 15.6mm), and Rustia kodagura n. sp. (males, 15.3mm; female, 10.3mm). The lack of infuscation on the distal fore wing veins between apical cells distinguish R. minuta n. sp. from R. apicata n. comb., R. kodagura n. sp., R. longicauda n. comb., and R. tigrina . The infuscation along the ambient vein of the fore wing in R. marginata n. comb. distinguishes it from R. minuta n. sp. Abdominal tergites 6–8 are dark brown or piceous in R. maculata n. comb. but only margined posteriorly in R. minuta n. sp. Finally, in R. minuta n. sp. the pygofer distal shoulder is curved laterad at its apex, extending to the level of the anal styles, the radiomedial crossvein is separated from the bifurcation of median veins 1 and 2 by more than its length, and the fore wing infuscation connects across apical cells 2 and 3 but in R. dentivitta the pygofer distal shoulder is straight, not curved, and extends well beyond the level of anal styles, the radiomedial crossvein is separated from the bifurcation of median veins 1 and 2 by less than its length, and the fore wing infuscation connects across apical cells 2–5.

Description. Basic colouration olivaceous, ochraceous, and piceous; some paratypes more piceous on head, thorax, and abdomen. Pattern on abdomen either continuous or discontinuous depending on amount of piceous pigment. Fore wings infuscation varying in intensity. Some females darker than males.

Head. Head including eyes narrower than prothorax and as wide as widest part of mesonotum, ochraceous marked with piceous. Areas around and lateral to ocelli piceous, posterior vertex and frons olivaceous and ochraceous. Epicranial suture olivaceous. Supra-antennal plate olivaceous with ochraceous anterior margin. Postclypeus olivaceous, with eight pairs of transverse grooves. Rostrum ochraceous with piceous tip, extending to hind coxa.

Thorax. Prothorax ochraceous and piceous with some olivaceous patches. Anteriorly broad and posteriorly fused piceous fasciae present on either side of the dorsomedially depressed midline. Paramedian fissures ochraceous, longer than heavily piceous lateral fissures which reach to median piceous fasciae. Ochraceous area between paramedian and lateral fissures marked with piceous. Lateral ambient fissure and pronotal collar lateral angle piceous. Pronotal collar width greater than anterior width of mesothorax and abdomen. Mesothorax ochraceous and olivaceous with central piceous fascia, sagittal sigillae not prominently marked, parapsidal suture piceous, lateral sigillae faintly marked with piceous as is lateral mesothorax. Scutal depression piceous. Cruciform elevation olivaceous. Posterior mesothorax piceous. Ventral segments olivaceous.

Legs. Ochraceous-olivaceous marked with piceous, covered with pile. Primary spine and secondary spine of fore femur of similar size, sharp at tip, secondary spine curved near tip, small apical spine present. Hind tibia olivaceous with piceous tibial spur and tibial comb.

Opercula. Male operculum small, scale-like, almost covering tympanal cavity, not encapsulating meracanthus medially, opercula well separated along midline, meracanthus tapering to point, reaching to or past posterior margin of operculum.

Wings. Fore wing hyaline, about 15mm in length, with 8 apical cells. Apex, radial, radiomedial, medial and mediocubital crossveins, radius anterior 2, radius posterior, median veins 1—4 and cubitus anterior 1 infuscated. Arculus piceous, costa and radius & subcostal vein ochraceous, node marked with piceous, distal subcostal vein and radius anterior ochraceous, remaining venation ochraceous proximally becoming piceous distally. Basal membrane greyish. Apical cell 1 longer than apical cell 2 and about same length as apical cells 3 and 4. Ulnar cells 1 and 3 distinctly longer than ulnar cell 2. Hind wings hyaline, about 7mm in length, with 5 apical cells, and ochraceous and piceous venation.

Abdomen. Timbals with four ribs ( Fig. 2 ), completely exposed, timbal covers rudimentary not covering any portion of timbal. Tergite 1 ochraceous medially, piceous laterally. Tergite 2 brownish with central piceous fascia and piceous fasciae on dorsolateral surface. Tergites 3—6 ochraceous with piceous fascia on dorsolateral surface, incomplete anteriorly on tergites 3 and 4, with transverse medial extensions. Tergites 7 and 8 with prominent piceous band covering most of the segments. Sternites ochraceous except for piceous marks on midline of sternite II and anterior of sternite III, either side midline on sternite VI and sternite VII are piceous. Ochraceous tubercles on lateral sides of sternites III and IV with tubercles on sternite III larger and more prominent. Tympanal cavity clearly visible.

Genitalia. Male pygofer ( Figure 1E–H ) – pygofer oblong, pygofer distal shoulder extended almost to level of anal styles, tapering to apex, curved laterad when viewed from posterior. Upper pygofer lobes directed slightly outward with lobed tips. Anal styles prominent. Uncus median lobe tapered ventromedialy, apex of uncus bifurcated with tips recurved medially. Aedeagus wider proximally with tapered distal end with basal plate bifurcated and extended laterally, hinge with curved cylindrical theca.

Measurments (MM). N = 8 males and 5 females, mean (range). Length of body: male 10.4 (9.9—12.6), female 9.8 (8.3—11.9); length of fore wing: male 14.7 (13.1—15.0), female 14.7 (14.0—15.7); width of fore wing: male 4.8 (4.5—4.9), female 4.8 (4.6—5.0); length of head: male 0.9 (0.7—1.2), female 0.9 (0.6—1.3); width of head including eyes: male 3.4 (3.2—3.7), female 3.4 (3.4—3.6); width of pronotum including suprahumeral plates: male 3.8 (3.6—4.0), female 3.8 (3.6—4.1); width of mesonotum: male 3.3 (3.0—3.4), female 3.3 (3.2—3.6).

Ecology and distribution. Rustia minuta n. sp. is currently known from a single location, Verlem in the South Goa District of the Indian state of Goa but may be found across the northern Western Ghats. Verlem has a mix of moist deciduous to semi-evergreen vegetation dominating the habitat ( Fig. 3 ). Adults were abundant and found mostly on shrubs or shrub-like plants. The adults are gregarious and interestingly, preferred to perch on the underside of leaves while they were calling. A single leaf was typically occupied by two or more individuals which made it easy to handpick them. Their activity did not cease due to heavy rains which indicates that R. minuta n. sp. could be a monsoon species with June representing the beginning of their season. The population did not appear to be biased towards a particular sex when sampled. We did not record their calls but the calls were feeble and almost inaudible. As new information on this species is generated, it will be made available on the Cicadas of India website (http://www.indiancicadas.org/sp/573/Rustia-minuta).

Figures

FIGURE 1. Dorsal and ventral sides of the holotype (A–B) and allotype (C–D), male genitalia (E–H) of Rustia minuta n. sp. Separate millimeter-scales are at the bottom of the type specimens and genitalia.

FIGURE 2. Timbal structures of Rustia minuta n. sp. (A) and Rustia kodagura n. sp. (B).

FIGURE 3. Habitat at the type locality of Rustia minuta n. sp.,Verlem, South Goa District, Goa (A) and Rustia kodagura n. sp., Honey Valley Estate, Kodagu District, Karnataka (B).