Duolandrevus (Eulandrevus) kawataredoki, Tan & Wahab, 2017

Tan, Ming Kai & Wahab, Rodzay Bin Haji Abdul, 2017, New taxa and notes on crickets of the subfamily Landrevinae (Orthoptera: Gryllidae) from Brunei Darussalam, Borneo, Zootaxa 4365 (4), pp. 440-454 : 442-449

publication ID	https://doi.org/ 10.11646/zootaxa.4365.4.4
publication LSID	lsid:zoobank.org:pub:5414E5C8-8360-454F-84C5-E17E8BAF7CB3
DOI	https://doi.org/10.5281/zenodo.6020195
persistent identifier	https://treatment.plazi.org/id/03AF5B28-045B-C270-FF2F-FC2E1DA1AEA6
treatment provided by	Plazi
scientific name	Duolandrevus (Eulandrevus) kawataredoki
status	sp. nov.

Treatment

Duolandrevus (Eulandrevus) kawataredoki , new species

( Figs. 3–6 View FIGURE 3 View FIGURE 4 View FIGURE5 View FIGURE 6 )

http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:500654

Material examined. Holotype (male): Brunei Darussalam, Ulu Temburong, Kuala Belalong Field Studies Centre, near Sungei Mata Ikan , primary ridge dipterocarp forest, calling inside hanging dead leaves on tree, N4.54727, E115.15701, 81.7 ± 9.1 m, 5 January 2017, 2003 hours, coll. M. K. Tan (KB.17.2) ( IBER). GoogleMaps

Paratypes: 1 female (KB.17.23), Brunei Darussalam, same locality as holotype, along Ashton Trail , primary ridge dipterocarp forest, feeding on dead leaves on tree, N4.54686, E115.15715, 116.1 ± 7.2 m, 6 January 2017, 2044 hours, coll. M. K. Tan GoogleMaps ; 1 male (KB.17.91), same locality as holotype, along Ashton Trail , primary ridge dipterocarp forest, calling inside hanging dead leaves on tree, N4.54614, E115.15677, 120.5 ± 6.1 m, 27 July 2017, 2053 hours, coll. M. K. Tan (all ZRC) GoogleMaps .

Subgeneric status. We consider this species to belong to the subgenus Eulandrevus based on the following diagnostic characters: hind wing absent, male anal plate unspecialized without strong setae at apex, and lack of dorsal denticle at and near base of each posterolateral epiphallic lobe. Although the epiphallus lacks distinct transverse fold (barely visible on lateral parts), the species may still be included in this subgenus with the absence of a single diagnostic character ( Gorochov, 2016).

Diagnosis. The new species differs from all known species of Duolandrevus (Eulandrevus) by the combination of the following characters: relatively small habitus; developed tegminal venation with mirror; metanotal gland transverse with two small deep oval depressions; posterolateral epiphallic lobe (when viewed dorsally) elongated and straight, pointing posteriorly, and with apex subacute, with internal process before posterior third of the lobe; posterolateral epiphallic lobe (when viewed laterally) roundly tapering into a narrowly truncated apex, without roundly angular dorsal projection; formula very short and stout.

Comparison with congeners. The new species resembles closely to Duolandrevus (Eulandrevus) borneo Gorochov, 2016 from Sabah by male genitalia; but differs by tegmen reaching sixth abdominal tergite (instead of fourth), pronounced mirror on the tegmen (highly reduced in D. (E.) borneo ); metanotal gland with two oval depressions (absence in D. (E.) borneo ); and anal plate more truncated (instead of rounded) apically. The male genitalia differs by posterolateral epiphallic lobe more slender and elongated rounded, not angulated and without roundly angular dorsal projection (instead of stouter and roundly angular in D. (E.) borneo ); internal process of posterolateral epiphallic lobe more elongated but less wide (in profile); formula (f) distinctly shorter.

The new species is also similar to Duolandrevus (Duolandrevus) rufus Chopard, 1931 from Peninsular Malaysia and Duolandrevus (Duolandrevus) kubah Gorochov, 2016 from Sarawak by the male genitalia but differs by tegminal venation; the lack of dorsal denticle at and near base of each posterolateral epiphallic lobe and shape of internal process of posterolateral epiphallic lobe; and length of formula.

The new species is also similar to Duolandrevus (Eulandrevus) tawau Gorochov, 2016 from Sabah, Duolandrevus (Duolandrevus) sabah Gorochov, 2016 from Sabah, and Duolandrevus (Duolandrevus) curup Gorochov, 2016 from Sumatra by the two oval depressions of the metanotal gland but differs by tegminal venation and genitalia.

Description. Fairly small and stout cricket: cylindrical, slightly dorso-ventrally compressed and fairly pubescent ( Fig. 3 View FIGURE 3 ). Head rostrum distinctly wider than scapus, with apex truncated (in dorsal view) ( Fig. 4A View FIGURE 4 ). Maxillary palpi with apical (fifth) segment elongated triangular, distinctly larger, broader, and longer than third and fourth segments, with apex swollen and obtusely rounded; subapical (fourth) segment slightly shorter than third segment ( Fig. 4B View FIGURE 4 ). Pronotum transverse; dorsal disc gently widens posteriorly, slightly wider at the posterior end than long; anterior and posterior margins with strong hairs; disc with anterior and posterior margins straight ( Fig. 4A View FIGURE 4 ); lateral lobe longer than tall; ventral margin of lateral lobe slightly concave in the middle ( Fig. 4B View FIGURE 4 ). Fore tibia with small and rounded inner and outer tympana. Hind tibia inner and outer margins with 4 stout articulated spurs (also known as movable spines) on each dorsal side; and 2–3 much smaller basal spines; inner margin with two long apical spurs, outer margin with one shorter apical spur (still longer than subapical spurs. Hind basitarsus with 4 inner and 4 outer denticles.

Tegmen not pubescent, extending to middle of 6th abdominal tergite ( Figs. 3 View FIGURE 3 , 4B View FIGURE 4 ); dorsal field with mirror oblong (longer than broad) and not separated by a vein, two cord veins, and eight harp veins (three anterior ones are small); anal area truncated; lateral field with five longitudinal veins ( Fig. 4C View FIGURE 4 ). Hind wings absent. Metanotal gland transverse, with two small oval depressions nearly separated in the middle; anterior margin feebly concave with long and strong hairs; posterior margin deeply concave in the middle ( Fig. 4D View FIGURE 4 ). Ninth abdominal tergite transverse, posterior margin slightly convex in the middle ( Fig. 4E View FIGURE 4 ). Anal plate (fusion of tenth abdominal tergite and epiproct) broad at basal half (wider than entire length), tapering to a slightly narrower apical half (about as wide as entire length, and wider than length of apical half); apex truncated with a few setae ( Fig. 4E View FIGURE 4 ). Subgenital plate slightly broader than long, tapering gently into a rounded apex ( Fig. 4F View FIGURE 4 ). Male genitalia as shown in Figs. 4G–J View FIGURE 4 . Male epiphallus deeply and fairly widely notched, not distinctly folded transversely (when viewed dorsally) ( Fig. 4G View FIGURE 4 ). Posteromedial epiphallic lobules (when viewed dorsally) directed posteriorly, slightly curved internally, and with almost acute apex; narrowly notched between the lobules ( Fig. 4J View FIGURE 4 ). Posterolateral epiphallic lobe (when viewed dorsally) elongated and straight, pointing posteriorly and slightly towards each other, apex subacute, with internal process before posterior third of the lobe ( Fig. 4G View FIGURE 4 ); (when viewed laterally) roundly tapering into a narrowly truncated apex, without roundly angular dorsal projection ( Fig. 4I View FIGURE 4 ). Internal process of posterolateral epiphallic lobe points anteriorly with obtuse apex; not touching, overlapping, or fusing with each other; but nearly touching the posteromedial epiphallic lobules (when viewed dorsally) ( Fig. 4G View FIGURE 4 ); elongated rounded (when viewed laterally) ( Fig. 4I View FIGURE 4 ). Principal apodeme widely forked posteriorly. Formula very short and stout, posterior apex broad (when viewed dorsally) ( Fig. 4G View FIGURE 4 ). Ramus not fusing together at the anterior end, with flattened and slightly membranous exterior plate near posterior third ( Fig. 4G View FIGURE 4 ).

Coloration. Generally red brown or brown. Head red brown; antenna scapus and antennal segments lighter brown. Gena red brown; clypeus maxillary palpi yellow brown with apical end of each segment white. Pronotum red brown. Tegmen red brown, but ventral half of lateral field transparent. Legs generally red brown, tibiae more of yellow brown. Hind femur mostly red brown, except ventro-internal area white; hind tibia generally red brown, dorsally dark brown apical of knee; spines on hind tibia red brown with black tips; hind tarsus brown; spines on hind tibia and tarsus brown with black tips. Thoracic segments white. Abdominal tergites and sternites (including subgenital plate) red brown; anal plate dark brown.

Female ( Fig. 5 View FIGURE5 ). Cylindrical, similar to male ( Fig. 5A View FIGURE5 ). Wingless ( Fig. 5B View FIGURE5 ). Metanotal gland absent ( Fig. 5B View FIGURE5 ). Ninth abdominal tergite transverse ( Fig. 5C View FIGURE5 ). Anal plate trapezoid, about as long as broad, flattened, tapering into a truncated apex; posterior margin with hairs ( Fig. 5C View FIGURE5 ). Subgenital plate also trapezoid broader than long, apex fairly narrow and truncated ( Fig. 5D View FIGURE5 ). Ovipositor relatively long, surpassing middle of hind tibia and nearly reaching apical spurs; slender, feebly thicken towards apical valves; dorsal valves slightly longer than ventral valves; valves with margin smooth and with apices acute (especially so for the dorsal valves) ( Fig. 5E View FIGURE5 ).

Measurements (in mm). Male BL = 11.0–12.2; HL = 2.2–2.3; PL = 2.7–2.8; PW = 3.1–3.5; TL = 6.7–5.8; HFL = 8.1–8.4; HTL = 5.2–5.3. Female BL = 12.4; HL = 2.4; PL = 3.0; PW = 3.6; HFL = 9.1; HTL = 5.7; OL = 6.5.

Male calling song ( Fig. 6 View FIGURE 6 ). The male produces trilling calls of various length (between less than 1 sec to slightly more than 2 sec). The calling song has a mean frequency of 5.0 kHz; mean dominant frequency of 4.6 kHz, maximum dominant frequency of 5.9 kHz, minimum dominant frequency of 3.2. kHz. Each thrill gets louder before plateauing; dominant frequency also increased from 3.8 kHz to 4.9 kHz.

Etymology. This species is named after kawataredoki (noun in apposition), a Romanized form of the antiquated Japanese word, translating to time of being “who he is” dusk or twilight. This reflects the interesting encounters of the strange cricket during dusk.