Neduba radocantans 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 : 61-63

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

Fig. 19 (distribution), Fig. 26 (male and female habitus, calling song, male and female terminalia, karyotype), Plate 3A (live habitus), Plate 5E (male calling song), Plate 8B (male ventral sclerite), Plate 10F (male titillators), Plate 12D (female subgenital plate).

Common name. Raspy Shieldback.

History of recognition. None.

Type material. HOLOTYPE MALE: USA, CA, El Dorado Co., Finnon Reservoir , 5 mi. NE Placerville, 38.780862N, 120.732843W, 790 m, 5-6-VIII-1995, DB Weissman, S 95-62 [stop], R95-49 [recording], T95-21 [testes], tegmen in gelcap and genitalia in vial below insect, deposited in CAS, Entomology type #19680.

PARATYPES (n = 17): USA, CA, El Dorado Co., 1♁, 2♀, same data as holotype; 4♁, 2♀, Finnon Reservoir , 5 mi. NE Placerville, 38.79978N, 120.74947W, 740 m, 8-9-VIII-2014, JA Cole, DB Weissman , LACM; 8♁, US50 3.7 mi. W Kyburz , 38.76427N, 120.35897W, 1112 m, 19-VII-2015, JA Cole, DB Weissman , LACM.

Measurements. (mm, ♁n = 12, ♀ n = 4) Hind femur ♁18.26–20.50, ♀ 19.48–21.29, pronotum total length ♁7.96–9.70, ♀ 7.85–8.85, prozona length ♁3.46–5.07, ♀ 3.89–5.08, metazona dorsal length ♁3.92–5.50, ♀ 3.32– 4.25, pronotum constriction width ♁2.20–2.63, ♀ 2.35–2.80, metazona dorsal width ♁5.47–6.41, ♀ 4.92–5.62, head width ♁4.40–4.75, ♀ 4.60–5.23, ovipositor length ♀ 13.45–18.05.

Habitat. Oak woodland understory and riparian. In tangles, leaf litter, and bunch grass under oaks. This species inhabits mixed conifer forests at lower elevations than does N. radicata , but the two overlap at the extremes of their elevational distributions.

Seasonal occurrence. Midsummer as indicated by scant records: July (19-VII-2015, JA Cole & DB Weissman, LACM) into August (9-VIII-2014, JA Cole, D.B. Weissman, LACM).

Distribution. West slope of the Sierra Nevada in the vicinity of the American River watershed.

Stridulatory file. (n = 5) length 3.2–3.4 mm, 200–250 teeth, tooth density 70.6 ± 5.5 (62.5–76.9) teeth/mm.

Song. (n = 19) Unique in the high PTN of 19.9 ± 3.9 (two-way ANOVA, P = 1.93×10 -15). The greater portion of airtime spent producing OPT makes the PTR slower (0.8 ± 0.3 s- 1, ANCOVA, P = 3.96×10 -9) than that of other Sierranus Group species. PTF is 16.2 ± 1.2 kHz.

Karyotype. (n = 6) Unique. 2n♁ = 22 (2m + 18t + XmYt), T95-20, S95-62, paratopotype.

Recognition. Males have both a high stridulatory file tooth density (68–73 teeth/mm) and a strongly constricted pronotum. Male N. sierranus have a similar high tooth density but the pronotum constriction is weak. N. inversa is difficult to separate but tends to have a lower stridulatory file tooth density. Female hind femora are shorter than other Sierranus and Sequoia group species. The song has the slowest PTR and highest PTN of the Sierranus Group. The latter song feature is temperature-invariate and distinct to a human listener, and thus may be used to identify this species in song surveys that lack temperature correction. Inhabiting the vicinity of the American River drainage, this species ranges the farthest north of any in the Sierranus Group ( Fig. 19 ).

Etymology. l. rado “scrape” + cantans “singing”. Refers to the rasping, abrasive sound quality of the numerous minor PT in the male song.

Notes. Distributed at the northern limit of the Sierranus Group, N. radocantans is sympatric with N. radicata , the species with the most southerly distribution in the Carinata Group where their elevational distributions overlap. Selection for mate recognition at a contact zone could have driven the evolution of the distinctive, elaborate song with numerous OPT in this species. The population near Kyburz, California was located with a bat detector while night driving. Males were common but no females could be found, even after trampling vegetation. N. radicata songs were heard in trees at this locality. The type locality of Finnon Lake is private property that is owned and managed by the Mosquito Volunteer Fire Association (www.gomvfa.org). The conservation prospectus of this area is unknown.

Material examined. Type series only, see Type material above.

Sequoia Group

The phylogenetically defined Sequoia Group includes the species extincta , inversa , sequoia , prorocantans , and duplocantans . Males of all but one of the four species are morphologically separated from the Sierranus Group by the lower stridulatory file tooth density (46–62 teeth/mm). Like the Sierranus Group, the species are diagnosed by song and karyotype and are morphologically cryptic; only measurements of body parts and stridulatory file tooth density differ. As in the Sierranus Group, each species occupies distinct watersheds in the Sierra Nevada, albeit farther south ( Fig. 8 ). This group contains the only pair of fully sympatric Neduba species within the same species Group.

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.

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 8. Ventral sclerites: Sierranus and Sequoia Groups. A. N. sierranus, B. N. radocantans, C. N. arborea, D. N. inversa, E. N. prorocantans, F–H. N. sequoia.

FIGURE 8. Distribution of Neduba species groups generated from records in this work.

PLATE 10. Titillator arms of Propsti (A), Castanea (B–C), Lucubrata (D), Sierranus (E–F), and Sequoia (G–I) Group species.

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 26. N. radocantans male and female habitus, calling song, male and female terminalia, karyotype.