Okanagana monochroma Smeds and Chatfield-Taylor, 2025

Smeds, Elliott A. & Chatfield-Taylor, Will, 2025, A new species of Okanagana native to a unique serpentine ecosystem in Northern California (Hemiptera: Auchenorrhyncha: Cicadidae), Zootaxa 5636 (3), pp. 487-498 : 488-494

publication ID	https://doi.org/10.11646/zootaxa.5636.3.4
publication LSID	lsid:zoobank.org:pub:2246BB0C-39F8-4244-A4F4-5C1172EBBAD1
DOI	https://doi.org/10.5281/zenodo.15595750
persistent identifier	https://treatment.plazi.org/id/7D48CB0B-FFD2-FF86-FF0D-8148E4ECCD50
treatment provided by	Plazi
scientific name	Okanagana monochroma Smeds and Chatfield-Taylor
status	sp. nov.

Treatment

Okanagana monochroma Smeds and Chatfield-Taylor , new species

Table 1 View TABLE 1 (measurements), Fig. 1 View FIGURE 1 (A. dorsal habitus, B. ventral habitus, C. male genitalia, right lateral view, D. male genitalia, dorsal view, E. female genitalia, ventral view, F. timbal, G. life appearance), Fig. 2 View FIGURE 2 (spectrogram and waveform of calling song), Fig. 3 View FIGURE 3 (geographic distribution), Fig. 4 View FIGURE 4 (habitat and female egg-nest).

Type material. HOLOTYPE: 1 male, USA, CA, Sonoma Co., The Cedars N of Cazadero , 38.61919°N, 123.132469°W, 15-VI-2024, EA Smeds, deposited in CAS, CASTYPE21827 GoogleMaps

PARATYPES: 1 female, USA, CA, Sonoma Co., The Cedars , 38.620583°N, 123.133754°W, 15-VI-2024, EA Smeds, CASENT 8525721 GoogleMaps ; 1 female, USA, CA, Sonoma Co., The Cedars , 38.620830°N, 123.133705°W, 15-VI-2024, EA Smeds, CASENT 8525722 GoogleMaps ; 1 male, USA, CA, Sonoma Co., The Cedars , 38.619294°N, 123.132705°W, 16-VI-2024, EA Smeds, CASENT 8525723 GoogleMaps ; 1 female, USA, CA, Sonoma Co., The Cedars , 38.620605°N, 123.133705°W, 16-VI-2024, EA Smeds, CASENT 8525720 GoogleMaps

Description. Head. Head including eyes as wide as front margin of pronotum. Rostrum black with narrow white borders around the base of the menta, extending to the middle coxae. Anteclypeus black with white medial spot at base of postclypeus. Postclypeus black, not strongly produced, median sulcus extending halfway down the anterior midline. Lora edged with white laterally, genae edged with white medially. Ventral surface of head densely coated in long white hairs. Supra-antennal plates white anteriorly and black posteriorly. Antennae black. Frons black with white on lateral portions of the frontoclypeal suture. Vertex uniform black only sparsely coated with short hairs, except for a border of long hairs surrounding the eyes. Eyes black in live specimens ( Fig. 1G View FIGURE 1 ) and dark brown in preserved specimens ( Fig. 1A View FIGURE 1 ).

Thorax. Pronotum shiny black with sparse covering of short white hairs. Humeral angles of pronotum rounded, anterior angles acute; lateral margins curved anteriorly, giving the pronotum a slightly tapered shape. Pronotal collar black with white posterior margin narrowing substantially around the dorsal midline. Mesonotum shiny black with sparse covering of short black hairs, with white markings as follows: triangular patch along the antero-lateral corner of mesonotum, directly posterior to humeral angle of pronotum; two pairs of spots along the lateral curve of the mesonotum; two obconical or crescent-shaped spots at the posterior tips of the submedian sigillae; in some specimens, a thin line extending from the pronotal collar partway down both parapsidal sutures; two spots at the anterior arms of cruciform elevation, directly lateral to scutellar depressions; along the lateral posterior margin of the mesonotum. Metanotum exposed at dorsal midline, bordered with white along mid-lateral margin ( Fig. 1A View FIGURE 1 ).

Wings. Wings hyaline with white basal membranes. Forewings with 8 apical cells, hindwings with 6. Costal node approximately halfway down the length of the forewing. Basal cell of forewing semi-opaque and whitish basally. Costal veins black along leading edge and white posteriorly. All other venation black ( Fig. 1A–B View FIGURE 1 ).

Legs. Coxae white medially and black otherwise. Meracanthus white with black basal spot. Trochanters black bordered distally with white. Fore femora black with distal white border; middle and hind femora black lined posteriorly and distally with white. Fore and middle tibiae black except for a narrow white band at the distal joint; hind tibiae white except for the proximal third or fourth. Tarsi uniform black ( Fig. 1B View FIGURE 1 ).

Abdomen. Tergum with a sparse coating of short white hairs, denser on the lateral surface; tergites shiny black narrowly edged with white on posterior margins, in some specimens only on the lateral portions. Markings broader on tergites 7 and 8, particularly in female specimens ( Fig. 1G View FIGURE 1 ). Venter with denser covering of longer hairs; sternites and epipleurites black bordered broadly with white. Timbals with 5 long and 5 short ribs ( Fig. 1F View FIGURE 1 ). Opercula rounded in shape, black with a large white medial patch, posterior margin bordered white.

Male terminalia. Uncus in dorsal view broad and elliptical in shape, with a blunt apex forming a very shallow notch ( Fig. 1D View FIGURE 1 ). In lateral view, dorsal surface very gently curved; ventral surface roughly parallel in the basal third and strongly curved apically ( Fig. 1C View FIGURE 1 ). Cross-section roughly triangular. Aedeagus long and whiplike, encapsulated in a groove on the underside of the uncus. Sternite VIII (valve) roughly triangular in lateral view, with a gently curved ventral surface, the dorsal edges straight in the middle third and curling gently toward the apex, coloration black with the anterior dorsal edge bordered in white ( Fig. 1C View FIGURE 1 ).

Female terminalia. Tergite 9 bordered medially with white. Sternite VII with rounded, parallel-sided apical prongs, primary notch trapezoidal with depth half the lateral length of Sternite VII. Secondary notch distinct, rounded ( Fig. 1E View FIGURE 1 ).

Bioacoustics. The male calling song of O. monochroma consists of a continuous train of syllables ( Fig. 2A View FIGURE 2 ) with low intraspecific variation in both syllable rate (148 ± 4 syllable/s; n = 5) and peak frequency (8.20 ± 0.33 kHz; n = 5). The intraspecific variation in both peak frequency and syllable rate is similar to other Okanagana and related genera ( Chatfield-Taylor & Cole 2019; Cole et al. 2023; Stölting et al. 2004; Sueur & Aubin 2003). In addition to this continuous calling song, males would intermittently produce a second song type that we informally term a “short phrase call”, consisting of a two-phase period of amplitude-modulation: a few seconds of low amplitude song terminating in a single high amplitude burst ( Fig. 2B View FIGURE 2 ). Such calls were made sporadically in between bouts of continuous calling, either as an apparent lead up to the continuous song or in response to the sound of other chorusing males. This type of short phrase call has also been observed in a few other Okanagana species, most notably O. magnifica and O. tristis Van Duzee, 1915 (EAS, pers. obs.; WCT, pers. obs.).

Diagnosis. Okanagana monochroma is a large-bodied Okanagana with no morphologically or phenotypically similar species. Both sexes can be readily distinguished from all other congeners by the combination of white basal membranes and black and white body coloration. The only other Okanagana with white basal membranes is O. canescens Van Duzee, 1915 , which may be differentiated by its slightly smaller size (body length 23 mm), strawcolored markings, extensive silvery pubescence across the dorsum, and ferruginous markings in the excavated portions of the pronotum.

Male specimens of O. monochroma may also be identified by the presence of 5 timbal ribs, a character shared only with O. arboraria Wymore, 1934 , O. magnifica Davis, 1919 , and O. sperata Van Duzee, 1935 . O. arboraria is a small species (23 mm) with an orange venter, extensive orange dorsal markings, narrow elongated wings, and eyes that protrude distinctly beyond the width of the head ( Wymore 1934). O. magnifica and O. sperata are larger (35 mm and 31 mm, respectively), with orange abdominal markings, no pale markings on the pronotal collar or mesonotum, hairy pubescence, and forewings with infuscated apical cells. In the lateral view the uncus of both O. magnifica and O. sperata is elongated, forming a distinct point at the apex, rather than blunt as in O. monochroma ( Davis 1919; Van Duzee 1935) ( Fig. 1C View FIGURE 1 ).

Female O. monochroma can be diagnosed by the shape of the notch of Sternite VII ( Fig. 1E View FIGURE 1 ), similar only to O. sequoiae ( Bliven 1964) View in CoL . This species can be diagnosed from O. monochroma by the orange venter, short, rounded wings, and eyes that protrude distinctly beyond the head as in the related O. arboraria View in CoL ( Bliven 1964; Cole et al. 2023; Wymore 1934).

If song recordings are available, then O. monochroma may be distinguished from all other sympatric species by its unique combination of syllable rate and peak frequency (see Bioacoustics). This may facilitate species identification during non-destructive acoustic surveys, or in instances when male singing perches are too inaccessible to allow specimen collection.

Etymology. From the Ancient Greek monókhrōmos, “of one color”, and the English derivative monochrome, in reference to this species’ distinctive black and white coloration.

Distribution. O. monochroma is so far known only from The Cedars, a 28 km 2 area in northwestern Sonoma County, California, underlain by ultramafic peridotite and serpentine rock ( Blake et al. 2016) ( Fig. 3 View FIGURE 3 ).

Seasonal occurrence. Occurrence records and personal correspondence indicate an above-ground flight period beginning in late April and extending into July.

Habitat and notes. Individuals were recorded in the Main Canyon of Big Austin Creek within The Cedars ( Fig. 4A View FIGURE 4 ). Males were observed calling primarily from the canopy of Sargent’s cypress ( Hesperocyparis sargentii ), which comprises most of the overstory of The Cedars and gives the area its (erroneous) name. Other common shrubs present along the creek and adjacent cypress forest include Brewer’s willow ( Salix breweri ), western azalea ( Rhododendron occidentale ), hoary coffeeberry ( Frangula californica subsp. tomentella ), leather oak ( Quercus durata ), toyon ( Heteromeles arbutifolia ), and Cedars creambush ( Holodiscus dumosus var. cedrorus ).

Females were repeatedly directly observed ovipositing on western azalea ( Fig. 4B View FIGURE 4 ). This species requires wet soil and grows in scattered stands along the creek. Azalea bushes in the Main Canyon all bore extensive scarring from past egg-nests ( Fig. 4C View FIGURE 4 ); no other plant species observed at The Cedars showed signs of such behavior, although oviposition in the upper branches of the cypresses could not be ruled out due to the height of the trees. One Okanagana exuvium was discovered in the same stand of azaleas where the 3 female paratypes were collected, however the presence of other Okanagana and Tibicinoides Distant, 1914 species in the canyon precludes any definitive assignment to this species.

Five other cicada species were recorded in The Cedars during the course of the fieldwork: Okanagana mariposa mariposa Davis, 1915 , an undescribed Okanagana species near O. tristis , Platypedia minor Uhler, 1888 , P. similis Davis, 1920 , and Tibicinoides rubrovenosa ( Davis, 1915) (EAS, pers. obs.; WCT & Jeff Cole, unpublished data). All five species are widespread in Northern California (iNaturalist; Sanborn & Phillips 2013), and can be found in serpentine and non-serpentine soils (EAS, pers. obs.).