Neduba duplocantans Cole, Weissman, & Lightfoot, 2021

Cole, Jeffrey A., Weissman, David B., Lightfoot, David C., Ueshima, Norihiro, Warchałowska-Śliwa, Elżbieta, Maryańska-Nadachowska, Anna & Chatfield-Taylor, Will, 2021, A revision of the shield-back katydid genus Neduba (Orthoptera: Tettigoniidae: Tettigoniinae: Nedubini), Zootaxa 4910 (1), pp. 1-92 : 70-72

Neduba duplocantans Cole, Weissman, & Lightfoot , sp. n.

Fig. 19 (distribution), Fig. 30 (male and female habitus, calling song, male and female terminalia, karyotype), Plate 3H (live habitus), Plate 5J (male calling song), Plate 12H (female subgenital plate).

Common name. Doubletime Shieldback.

History of recognition. None.

Type material. HOLOTYPE MALE: USA, CA, Tulare Co., South Fork Road , 9.75 miles southeast of Three Rivers, 36.35334N, 118.78451W, elev. 970 m, 25-VI-2017, JA Cole, W Chatfield-Taylor, 170625_03 [recording], JCT17-1 [karyotype], 173 [teeth], 3.4 [mm], tegmen in gelcap below specimen, deposited in CAS, Entomology type #19709.

PARATYPES (n = 24): Fresno Co., 1♀, Big Creek Road, 5 mi. S of Bretz Mill Campground, 36.97546N, 119.21088W, 810 m, 13-VIII-2015, JA Cole, LACM ; Tulare Co., 3 ♁, 8♀, same data as holotype, LACM ; 2♁, same data as holotype, CAS ; 1♀, same data as holotype, JAC ; 1♁, 1♀, South Fork Campground , Sequoia National Park, 36.35209N, 118.76511W, 1112 m, 12-13-VIII-2015, JA Cole, CAS ; 1♁, 6♀, same data except LACM .

Measurements. (mm, ♁n = 7, ♀ n = 17) Hind femur ♁19.46–21.95, ♀ 21.44–22.69, pronotum total length ♁8.20–9.28, ♀ 8.10–8.95, prozona length ♁3.30–4.71, ♀ 3.48–5.28, metazona dorsal length ♁4.42–5.44, ♀ 3.09– 4.75, pronotum constriction width ♁2.00–2.35, ♀ 2.03–2.95, metazona dorsal width ♁5.60–6.05, ♀ 5.20–6.41, head width ♁4.60–5.12, ♀ 4.85–5.85, ovipositor length ♀ 13.09–17.60.

Distribution. At present, known only from the vicinity of the Kaweah River in the Sequoia National Forest.

Habitat. Found in tangles and among grass along a stream flowing out of a side canyon. Also collected on bushes along the road paralleling the Kaweah River.

Seasonal occurrence. Males were active and females were a mixture of last instar nymphs, teneral adults, and mature adults in late June (25-VI-2017, JA Cole & W Chatfield-Taylor, LACM). By August this species was rare (12-VIII-2015, JA Cole, LACM). This species may be active earlier in the season than sympatric N. sequoia .

Stridulatory file. (n = 7) length 2.7–3.4 mm, 126–173 teeth, tooth density 51.0 ± 4.9 (45.8–60.7) teeth/mm.

Song. (n = 7) Unique. The PTR of 5.1 ± 0.3 s- 1 is much faster than any other Sequoia or Sierranus Group species, and twice as fast as sympatric N. sequoia . The MPTL is brief at 72.3 9.1 ms. The short MPTL contributes to a low PTdc of 35.8 ± 4.9%. PTF of 17.0 ± 1.0 kHz is higher than other Sequoia Group species and is difficult to hear except at short range.

Karyotype. (n = 3) 2n♁= 21 (18t + XtXtYm), shared with N. sierranus, JCT 15-12, paratopotype.

Recognition. Male N. duplocantans are separated from sympatric N. sequoia by stridulatory file tooth density (47–52 teeth/mm vs. 55–59 teeth/mm, respectively). To the north, N. inversa has a similarly constricted pronotum but that species also has a higher tooth density (64–68 teeth/mm). Male N. prorocantans to the south have similar stridulatory files but have a weakly constricted pronotum. The fast song PTR is unique, and readily separates this species by ear from syntopic N. sequoia as well as from neighboring N. prorocantans to the south, as well as N. inversa to the north due to the multiple OPT in that species. Adult activity apparently commences earlier in the season than N. sequoia in areas where they co-occur, but the two species may be found together in midsummer.

Etymology. l. duplo “twice as much, double” + cantans “singing,” referring to the rate of PT production that is twice as fast as a sympatric congener.

Notes. This species was discovered by song while collecting a series of N. sequoia , and its distinctiveness was appreciated further when cytogenetic analysis revealed a distinct karyotype. The discovery of two morphologically cryptic Sequoia Group species ( N. duplocantans and N. sequoia ) that are both sympatric and syntopic is of considerable evolutionary interest. The species pair has diverged in several aspects: calling song, karyotype, and phenology. The calling song PTR differed by a factor of two. Considering the remarkably different songs and distinct karyotypes, stasipatric and secondary contact hypotheses should be tested in the Sequoia Group. With N. duplocantans adult activity commencing before N. sequoia have matured, allochronic isolation may also be evolving between the two species. Two females among the paratype series were identified through rDNA sequence ( Figs. 4-5 ). Introgression of mtDNA among the Sequoia Group species ( Fig. 4 ) is expected if young, geographically proximal species have a history of hybridization as observed in Aglaothorax (Cole 2016) .

Material examined. (n = 2) Tulare Co., in addition to Type material (above), 1♀, Hammond , Kaweah Powerhouse 3 Forebay, 36.48618N, 118.83553W, 853 m, 17-VIII-2010, W Chatfield-Taylor, LACM ; 1♀, Ash Mountain , Kaweah Power Station 3, 36.48606N, 118.83586W, 7-VI-1986, DJ Burdick, CAS .

Figures

PLATE 3. Live habitus of the Sequoia Group. A. N. radocantans paratype male, B. N. arborea paratopotype male, C. N. inversa paratype male, D. N. prorocantans paratype male, E. N prorocantans paratype female, F. N. sequoia paratype male, G. N. sequoia paratype female, H. N. duplocantans paratopotype male singing.

FIGURE 4. Comparison of A. rDNA, and B. mtDNA trees. Nodes with <85% posterior probability are collapsed. Species Groups are color coded.

FIGURE 5. rDNA Bayesian consensus tree. Nodes with <85% posterior probability are collapsed. Species Groups are color coded, and species hypotheses are indicated.

PLATE 5. Male calling songs of the Castanea, Lucubrata, Sierranus, and Sequoia Groups. A. N. castanea, B. N. macneilli, C. N. lucubrata, D. N. sierranus, E. N. radocantans, F. N. arborea, G. N. inversa, H. N. prorocantans, I. N. sequoia, J. N. duplocantans. Left column shows 4 s oscillogram windows, right column are 1 s windows.

PLATE 12. Female subgenital plates of Lucubrata (A), Sierranus (B–D), and Sequoia (E–H) Group species.

FIGURE 19. Distribution of Propsti, Castanea, Lucubrata, Sierranus, and Sequoia Group species mapping records reported in this work.

FIGURE 30. N. duplocantans male and female habitus, calling song, male and female terminalia, karyotype.