Endodrelanva nympha, 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 : 449-453

Endodrelanva nympha , new species

( Figs. 7 , 8 )

http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:500655

Material examined. Holotype (male): Brunei Darussalam, Ulu Temburong, Kuala Belalong Field Studies Centre, near Sungei Mata Ikan , primary ridge dipterocarp forest, on tree branch near a female, N4.54728, E115.15711, 131.1 ± 6.8 m, 29 July 2017, 1915 hours, coll. M. K. Tan (KB.17.115) ( IBER).

Generic status. We hypothesize that our species belongs to the genus Endodrelanva Gorochov, 2000 on the basis of these characters: reduced stridulatory apparatus; dorsal field of tegmen longer (very slightly) than lateral field; roundly angular apex of tegmen; absence of outer tympanum; anterior epiphallic part raised (only slightly); and rachis distinctly produced beyond apices of posteromedial epiphallic lobules.

This peculiar species has characters of subgenera Jorama Otte, 1988 , and Vietlandrevus Gorochov, 1996 of the genus Duolandrevus . It shares characters of subgenus Jorama : metanotal gland relatively small; reduced venation of tegmen (with obsolete mirror), and closely spaced and plate-like apex of posterolateral epiphallic lobe. However, it differs from Jorama by the absence of small denticles at apex of posterolateral epiphallic lobe. It also shares characters with species from the subgenus Vietlandrevus for the following characters: hind wing absent, tegmen with dorsal field longer than lateral field, male anal plate without strong setae at apex, and posterolateral lobes of epiphallus without denticles or tubercles. However, it differs by the presence of developed metanotal gland.

This species also has characters of genera Kotama Otte, 1988 , and Repapa Otte, 1988 but differs by the combination of these characters: presence of tympana (absence in Kotama ), paired posteromedial epiphallic process (instead of unpaired in Repapa ).

Diagnosis. The new species differs from all known species of Endodrelanva by the combination of the following characters: dorsal field of tegmen only very slightly longer than lateral field; metanotal gland with a rectangular depression, with setose depression, anterior, and posterior margins; anterior epiphallic part only slightly raised; posterolateral epiphallic lobe plate-like at the apex with a dorsal projection and a shorter ventral projection.

Comparison with congeners. The new species is similar to E. peculiaris Gorochov, 2016 , and E. chopardi Gorochov, 2016 from Sabah by the rectangular shape of metanotal gland; and posterolateral epiphallic lobe platelike at the apex with a dorsal and ventral projections (in profile view). It however differs from the two species by apex of dorsal tegminal field (not tapering acutely); anterior epiphallic part only slightly raised (instead of strongly raised).

The new species also differs from E. tomentosa (Chopard, 1931) from Peninsular Malaysia, E. macrorachis Gorochov, 2016 from Sabah, and E. jimini Tan & Kamaruddin, 2016 from Singapore by apex of posterolateral epiphallic lobe (plate-like instead of falcate in profile); and shape of metanotal glands (posterior margin not concave). The new species is similar to Endolandrevus [perhaps Endodrelanva sensu Gorochov (2016) ] pubescens Chopard, 1930 from Sarawak by shape of male tegmen but differs by smaller size (BL = 14.9 vs. 18 mm; PL = 3.1 vs. 3.5 mm; HFL = 10.4 vs. 12 mm), shorter tegmen length (4.9 vs. 6 mm); hind tibiae with more subapical spurs; first chord of tegmen substraight (clearly not sinuated), chords closer to one another than with diagonal vein (chords and diagonal vein about equal distance to one another); lateral field of tegmen with four longitudinal veins (instead of six). Until the holotype can be located and genitalia dissected, we cannot confirm that the two species are clearly different.

Description. Body dorso-ventrally compressed and fairly densely pubescent ( Fig. 7 ). Head rostrum about as wide as scapus, with apex truncated (in dorsal view) ( Fig. 7 ). Maxillary palpi with apical (fifth) segment triangular (longer than broad); distinctly larger, broader and longer than third and subapical (fourth) segments, with apex obtusely rounded; fourth and third segments subequal length ( Fig. 8A ). Pronotum transverse, about as wide as long, longer but about as wide as head; anterior and posterior margins with strong hairs; disc with anterior and posterior margins straight ( Fig. 7 ). Pronotal lateral lobe longer than tall, anterior half taller than posterior half ( Fig. 8A ). Fore tibia with small round inner tympanum but without outer tympanum. Hind tibia inner and outer margins with 5 stout articulated spurs (also known as movable spines) on each dorsal side; and about 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 pubescent, extending to middle of 4th abdominal tergite, dorsal field longer than lateral field; eight harp veins (three anterior ones are small); anal area roundly obtuse ( Fig. 8B ); lateral field with four longitudinal veins ( Fig. 8A ). Hind wings absent. Metanotal gland with a rectangular depression not separated by a ridge in the middle; depression, anterior and posterior margins with setae ( Fig. 8C ). Ninth abdominal tergite transverse, slightly convex along posterior margin ( Fig. 8D ). Anal plate broadly rounded at basal half (wider than entire length), tapering to a slightly narrower apical half (and wider than length of apical half), with truncated apex ( Fig. 8D ). Subgenital plate triangular, about as long as wide, with subacute apex ( Fig. 8E ). Male genitalia as shown in Figs. 8F–I . Male epiphallus narrowly notched, with transverse fold (when viewed dorsally) ( Fig. 8F ); anterior part slightly curved dorso-anteriorly (when viewed laterally) ( Fig. 8H ). Posteromedial epiphallic lobule elongated and directed posteriorly, and with acute apex; very deeply and narrowly notched between the lobules ( Fig. 8I ). Posterolateral epiphallic lobe plate-like at the apex (when viewed laterally); at the apex with a dorsal projection and a shorter ventral projection (when viewed laterally) ( Fig. 8H ). Rachis (or ectophallic fold) elongated, surpassing posterior of posteromedial epiphallic lobule and nearly reaching the posterior end of posterolateral epiphallic lobe ( Figs. 8F, 8G ). Apodeme principale narrowly forked posteriorly, forming a Y-shape (when viewed dorsally); posterior apex narrows just anterior of the bulbous apex. Formula elongated, narrow anteriorly (when viewed dorsally) ( Fig. 8F ), flattened and raised (when viewed laterally) ( Fig. 8H ). Ramus not fusing together at the anterior end, with flattened and slightly membranous interior plate near posterior third ( Fig. 8F ).

Female. Not known.

Coloration. Generally red brown or brown. Head red brown, antenna scapus lighter brown. Gena, maxillary palpi and clypeus pale to yellow brown. Pronotum red brown. Tegmen red brown. Legs yellow brown. Hind femur mostly light brown, but with a pale band at apical third red brown near knee; hind tibia red brown; hind tarsus yellow brown; spines on hind tibia and tarsus brown with black tips. Thoracic segments pale yellow brown, meta- and meso-sterna brown with dark margins. Abdominal tergites and sternites dark red brown, male anal plate and subgenital plate dark brown. Abdominal sternites and male subgenital plate yellow brown.

Measurements (in mm). BL = 14.9; HL = 2.0; PL = 3.1; PW = 3.4; TL = 4.9; HFL = 10.4; HTL = 6.9.

Etymology. The species can be reckoned to a wood nymph (mythological spirit inhabiting wood); in Latin, nympha = nymph (feminine). These crickets generally tend to hide among woods ( Fig. 9 ).

Figures

FIGURE 7. Endodrelanva nympha sp. nov. male habitus in dorsal view. Scale bar: 5 mm.

FIGURE 8. Endodrelanva nympha sp. nov. male: body in profile view (A), tegmen in dorsal view (B), metanotal gland in dorsal view (C), abdominal apex in dorsal (D) and ventral (E) views, genitalia in dorsal (F), ventral (G) and profile (H) views, and posteromedial epiphallic lobule (I). Scale bars: 2 mm (A), 1 mm (B–F).

FIGURE 9. Endodrelanva nympha sp. nov. male in natural environment in Kuala Belalong forest.