Axiagastus yeshwanthi Salini, Kment & Webb, 2025

Kment, Petr, Lemaître, Valérie A., Webb, Michael D. & Roca-Cusachs, Marcos, 2025, Revision of the Austro-Oriental shield-bug genus Axiagastus (Hemiptera: Heteroptera: Pentatomidae), with the description of five new species, and taxonomic notes on related genera, Zootaxa 5603 (1), pp. 1-82 : 66-74

Axiagastus yeshwanthi Salini, Kment & Webb sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:82391F64-363C-49EA-B9C7-BB23F06C66F6

( Figs 226–261)

Axiagastus rosmarus (misidentification, partim): Walker (1867): 269 (distribution: Thailand); Atkinson (1888): 129 (catalogue, redescription, distribution; partim; India: Assam); Kirkaldy (1909): 126 (catalogue, distribution; partim; India: Assam, Thailand).

Axiagastus rosmarus (misidentification): Distant (1879): 44 –45 (distribution); Distant (1902): 179, fig. 107 (figures of dorsal habitus, mesothorax, metathorax and abdomen in ventral view), 181 (redescription, distribution); Takara & Hidaka (1960): 183 –184, fig. 2 (distribution; Japan: Ryukyus ); Miyamoto (1965): 228 (distribution; Taiwan); Takara & Azuma (1972): 102 (distribution; Japan: Ryukyus ); Takara &Azuma (1973): 162 (checklist); Hsiao & Zheng (1977): 132 [footnote] (distribution; Taiwan); Zhang (1985): pl. XLVIII: fig. 176 (habitus drawing); Miyamoto & Yasunaga (1989): 184 (checklist; Japan); Lin & Zhang (1993): 123, fig. 34 (redescription, habitus illustration, distribution; China: Fujian); Yasunaga et al. (1993): 228, pl. 110: figs 304a,b (diagnosis, habitus photos of adult and last instar larva, plant association, distribution); Hayashi (2002): 147 (checklist; Japan: Ryukyus ); Fan (2011): 71 (key to species), 73–74, figs 2.30 a–g (redescription, drawings of male and female genitalia, distribution: China: Guangdong, Jiangxi), 559–560, figs 64–65 (habitus photos in dorsal and ventral view); Aoyagi (2014): 65 –66 (plant association, distribution); Hayashi et al. (2016): 496 (checklist; Japan: Ryukyus ).

Axiagastus Rosmarus (misidentification): Atkinson (1884): 167 (checklist).

Axiagastus Rosmarus (misidentification, partim): Lethierry & Severin (1893): 170 (catalogue, distribution; partim; India, Thailand).

Axiagastus rosmarius (incorrect subsequent spelling, misidentification): Arnold (2011): 43 (variability, distribution; Taiwan,? Thailand).

Axiagastus sp. 003-ARN: Arnold (2012): 56 (distribution; Taiwan).

Type locality. India, Degro, N Lak Limpur [?= North Lakhimpur, Assam].

Type material. Holotype: ♂ ( Figs 226‒228, 240), “ INDIA: [p] / Degro , N Lak Limpur. [p] / 23.viii.1911. [hw] / H. Stevens. [p] / B. M. 1962–489. [p] // Dapla Hills [p] / Upper Assam. [p] // Holotype [p, red-margined disc] // NHMUK 013590073 [p] // HOLOTYPUS / AXIAGASTUS YESHWANTHI / Salini, Kment & Webb sp. nov. / det. Salini. S & Kment, P., 2024 [p, red label]” ( BMNH). The holotype is pinned through the scutellum, left antennomeres IIb–IV and right antennomeres III–IV lost, left pro- and metatarsomeres II and III, whole right protarsus and right midleg lost; large hole in ventral side of meso- and metathorax.

Paratypes (10♂ 8♀): INDIA: Assam : 1♂, “ Assam // Atkinson / Coll. / 92–6 [p]” ( BMNH) .— Meghalaya: 1♂, “ Meghalaya // Khasia / 4500 [p] // Rosmarus Dall. [?] // Distant Coll. / 1911–383 [p] // dissected and illustrated Salini. S. [p]” ( BMNH) . The dissected male genitalia are placed in a glass microvial with glycerol attached to the same pin. Antennomeres III–IV of both antennae lost, tarsi and tibiae of right foreleg broken and glued on a card, right mesotarsus, left metatarsomeres II–III lost, hemelytra and hindwings damaged.— Andaman and Nicobar : 1♀, “Andaman & Nicobar / Middle Andaman: Rangat / 12° 30′ 19.4″ N 93° 55′ 05. 9″ E / 17.2 mts, 20.iv.2014, light trap / Yeshwanth. H. M. [p] // dissected and illustrated by Salini. S. [p] // Axiagastus rosmarus Dallas / Det. C. A. Viraktamath [p]” ( UASB) . The dissected female genitalia are placed in a glass microvial with glycerol attached to the same pin, terga and sterna (after extraction of terminalia and spermatheca), glued on a card, antennomeres III and IV glued on a card, right mesotarsi and claws lost.— JAPAN: Ryukyus : 1♂, “[two lines in Japanese script] / [JAPAN]: the Ryukyus / Okinawa Isls., Tokashiki Is. , / near Tokashiku beach. / 27. IV. 2019. H. Shigetoh leg. [p] // SIHU Collection [p] // Axiagastus rosmarus / Dallas, 1851 / Det. J. Souma, 2023” ( SIHU) .— TAIWAN: 1♀, “20110402 / Shan Ping / Kaohsiung / Liu L. Y. [hw] // Taiwan / Kaohsiung Coun- / ty, Shan Ping / 02. April 2011 / leg. L.-Y. Liu (♀) [hw] // Axiagastus ♀ / rosmarus / DALLAS, 1852 [hw] / det. ARNOLD 20.[p]12[hw]” ( ZSMC) ;— 1♂, “TAIWAN: Nantou Prov. / Sun Moon lake env. / N 23.82° E 102.94°, 800m / J. Halada, 25.5.2012 [p]” ( NMPC) ;— 1♂, “TAIWAN: Taitung Prov. / Schouchia env., 315 m / N22°207′ E120°860′ / J. Halada , 18.5.2012 [p]” ( NMPC) ;— 1♂, “TAIWAN: Taipei / 1997 / COL. [ñĕē: Dai Weiyu] [p] // coll. NCHU [hw, yellowish label] // ♂ [p]” ( NCHU) ;— 1♂, “TAIWAN: Taichung City. / NCHU ([中®大*: Chung Hsing University ]) / 2010. VII. 30. leg. [唐DZ廸: Tang Changdi] [p] // 2019.VII.30 / NCHU [DZ廸: Changdi] [p, pencil] // coll. NCHU [hw, yellowish label] // ♂ [p]” ( NCHU) ;— 1♀, “TAIWAN: Taichung City. / NCHU ([中®大*: Chung Hsing University ]) / 2010. XI. 4. leg. [öëü: Lin Yuzhe] [p] // 2010.II.4 / [台中: Taichung] NCHU / [āạ: A Jiao] [p, pencil] // please deposit / in NMNS [hw, yellowish label] // ♀ [p]” ( NMNS) ;— 1♂, “TAIWAN: Taichung Co. / Dasyueshan logging Rd. / [大ĪƜöDz: Dasyueshan logging Rd. ] by light. / 2010. VI. 7. leg. [侯ẅĕ: Hou Shunwei] [p] // 2010.VI.7 / [大ĪƜöDz 侯: Dasyueshan logging Rd. Hou ] / by light [hw, pencil] // please deposit / in NMNS [hw, yellow label] // ♂ [p]” ( NMNS) — [New Taipei City]: 1♀, “ V-29-2004. [坪ö: Pinglin] / ♀ [hw] // please deposit / in NMNS [hw, yellow label] // ♀ [p]” ( NMNS) .— THAILAND: 1♂, “ Siam [hw] // Saunders. [p] / 65.13 [p] // Type [p, green-margined disc] // NHMUK010582891 [p] // 1. AXIAGASTUS ROSMARUS , [p]// mislabelled [hw] / as type of [hw] / A. rosmarus . [hw] / det. M. D. Webb [hw] / 2023 [hw]” ( BMNH) ;— 1♂, “S THAILAND / PHUKET / S. & M. MURZIN lgt.” ( NMPC) ;— 1♀, “THAILAND: Chaiyaphum, / Province, Chulabhorn Dam / 16°32′04″N 101°38′32″E, 785 / m alt., light trap, 16 Apr 2013, / A. Wolski A. & M. A. Mazur [p]” ( NMPC).— VIETNAM: 1♀, S.VIETNAM, Phan-Rang, / Nha-Ho, 16.IV.–4.V. / 82, Soldán [p] // COLLECTIO / Moravské muzeum / Brno [p]” ( MMBC) ;— 1♀, “Vietnam, Yên Bái. / 4/2023. Local / Collector [p] // Roca-Cusachs / collection [p]” ( MRCC); 1♀, Vietnam, Yên Bái. / 8/2023. Local / Collector [p] // Roca-Cusachs / collection [p]” ( MRCC) ;— 1♀, Vietnam (mer.), Nam Cat Tien NP, 1.– 15.5.1994, P. Pacholátko & L. Dembický lgt. ( NHMW) .— Each specimen bears the following identification label: “ PARATYPUS / AXIAGASTUS YESHWANTHI / Salini, Kment & Webb sp. nov. // det. Salini, S. & Kment, P., 2024 [p, yellow label]” .

Additional material examined: CAMBODIA: 1♀, “CAMBODIA SW, 3 - 19 May 2005 / 20 km SE Koh - Kong / Tatai riv. env., 11°34´N; 103°07´E / E. Jendek et O. Sauša lgt. [p] // EX COLLECTIO / Z. JINDRA, PRAGUE [p]” ( ZJPC). Due to the very small size, unusually dark colouration and lack of associated male the identification of this female is only tentative .

Description. Colour, integument and vestiture ( Figs 226, 228, 229, 232–235, 236‒239). Ground colour of head, pronotum, and scutellum yellowish to light-orange yellow with coarse, black punctures scattered over disc of pronotum and scutellum (except scutellar apex devoid of punctures); disc of head with punctures fine, black, arranged in longitudinal rows; lateral margins of head including apices of mandibular plates black; antennae: each scape (I) concolourous with body surface, basipedicellite (IIa) either concolourous, pale or black, distipedicellite (IIb) brown with pale base or black, flagellomeres (III and IV) dark brown to black; lateral margins of pronotum (including part of humeral margins) black; pronotal disc usually luteous with uniformly distributed punctation, less usually pronotal disc posteriorly with dark brown transverse stripe (either ending at anterolateral angles of scutellum or extending continuously to humeral angles); prefrenal disc of scutellum anteriorly with pale transverse callose stripe, posteriad of it with moderately large, transverse, oval, black, medially divided spot (either partly or completely); another, thick, transverse inverted U-shaped spot anteapically, brown or black; scutellar apex with whitish to yellow spot devoid of punctures, anterior margin of the spot bisinuous, shape of spot unique within the genus; punctation on scutellum more concentrated on lateral and postfrenal region of disc; coria variable, from luteous with coarse, black, uniformly scattered punctures, to chocolate brown with scattered minute yellow callosities; membranes smoky brown; connexiva with extreme lateral margins including anterior and posterolateral angles of abdominal ventrites III–VII black; narrow lateral marginal stripe of connexiva, mesad of extreme lateral margin, luteous, devoid of punctures; narrow transverse stripe on anterior and posterior margins of connexival segments black, median region with dark brown, fine punctures. Ventral surface of body bright orange yellow with sparse punctures; head on ventral surface with a row of brown punctures on either side of bucculae; fine brown punctures arranged as broken transverse stripes especially on anterior and posterior margins of pro-, meso- and metapleura; punctures on abdomen sparse, mostly arranged as transverse rows anterior to intersegmental sutures of abdominal ventrites; femora with round, coarse, brown punctures arranged as longitudinal rows, tibiae with dense, coarse brown punctures arranged in rows; apices of buccular denticles, labium, and tarsal claws, one spot at apex of each ostiolar peritreme, one row of small spots sublaterally on ventrites III–VII, antero- and posterolateral angles of ventrites III–VII; a sublateral row of small spots mesad to spiracles coalescing spiracular outline, black.

Structure. Labium reaching ventrites III–IV. Prosternum impressed, mesosternum with more or less well-developed,keel-like carina;mesosternal carina with anterior apex rounded,terminating between prothoracic acetabula, posteriorly contiguous with more or less flat metasternal carina. Other characters as in generic redescription.

Male genitalia ( Figs 231, 240, 242–258). Genital capsule ( Figs 242–245, 249–252) subquadrate, as in Axiagastus luteipes Salini & Roca-Cusachs sp. nov., especially dorsal rim, and moderately developed, tongue-like distension (dn) visible on ventral rim of genital capsule; dorsal sinus of posterior aperture broadly U-shaped, ventral margin of posterior aperture semicircular; ventral rim including posterolateral angles bordered with a row of short, golden setae; posterolateral lobes in lateral view as shown in Figs 245, 252; ventral rim (vr) broadly, shallowly concave at middle, narrowly concave shallow sublateral to posterolateral lobes; infoldings of ventral rim deeply impressed on either side of moderately developed distension at middle, distension emarginated with shallow, V-shaped incision at middle, visible on ventral and dorsal views of genital capsule; infoldings of ventral rim laterally (mesad of posterolateral lobes) and laterally to base of median distension with a prominent, apically acuminate, sclerotized, black denticle (dt). Paramere ( Figs 246–248, 253–255) simple, crown finger-like with dorsal margin (dm) obtusely angulate at one-third in lateral view ( Figs 246, 253, 254), numerous fine, short setae on finger-like process (flp) of crown, elongate setae along periphery of laminate disc; crown gradually narrowed towards apex; apex rounded, not acuminate in lateral view; stem moderately elongate, apodeme disc-like. Phallus ( Figs 256–258). Articulatory apparatus (ap) as in Figs 256‒258; phallotheca nearly as long as endophallus, less sclerotized, distal part transparent with ventral convex projection (vcp) in close proximity with inner margin of processes of aedeagus; two pairs of dorsal conjunctival processes: dp1 and dp2 placed one above other; lower one (dp2) partly sclerotized throughout its length, apically rounded, upper one (dp1) completely membranous, shorter than dp2; aedeagus (ad) short, deflected dorsad, apex swollen, drop-like, transparent, with embedded phallotreme, processes of aedeagus elongate as in Fig. 258.

Female genitalia ( Figs 241, 259–261). Terminalia ( Figs 259, 260) as in A. rosmarus with inner posterolateral angles of valvifers VIII obtusangulate; valvifers VIII and IX as in A. rosmarus . Laterotergites VIII and IX as in A. rosmarus except for a minute, sclerotized, black denticle on outer margin of each laterotergite VIII. Gynatrium as in A. rosmarus . Spermatheca ( Fig. 261) as in A. cambelli ; apical receptacle orbicular with three ductules; a pair of short, subequal tubules nearly half as long as third one.

Differential diagnosis. This species can be differentiated by the presence of a more or less well-developed, keel-like carina on the mesosternum, apical margins of the mandibular plates convex or rounded, the scutellar disc anteriorly with a dark-brown to black round spot, usually medially divided, and the apex of the scutellum with a transverse, anteriorly bisinuate whitish spot, and also by the distinct male genitalia characters, such as the shape of the dorsal and ventral rims of the male genital capsule, the shape of the parameres and the shape of the processes of the aedeagus.

Etymology. This new species is named in honor of our colleague H. M. Yeshwanth (Hesaraghatta, Bangalore, Karnataka, India), for his exceptional collecting skills, which enable him to find rare specimens during insect surveys. The species-group name is a noun in the genitive case.

Plant association. In the Ryukyu Islands, adults of A. yeshwanthi sp. nov. are frequently attracted to the seeds of Arenga tremula Becc. var. engleri Hatsusima ( Arecaceae ) (e.g., Yasunaga et al. 1993, Aoyagi 2014, both as A. rosmarus ).

Distribution. This species is known from Cambodia (this paper); China: Fujian ( Lin & Zhang 1993, as A. rosmarus ), Guangdong ( Fan 2011, as A. rosmarus ), Jiangxi ( Fan 2011, as A. rosmarus ); India: Assam ( Atkinson 1884, 1888, as A. rosmarus ), Meghalaya ( Distant 1879, 1902, as A. rosmarus ), and Andaman & Nicobar Is. (Rangat, this paper); Japan: Ryukyus ( Takara & Hidaka 1960; Takara & Azuma 1972, 1973; Miyamoto & Yasunaga 1989; Yasunaga et al. 1993; Hayashi 2002; Aoyagi 2014; Hayashi et al. 2016, as A. rosmarus ); Taiwan ( Hoffmann 1935b, Miyamoto 1965, Arnold 2011, all as A. rosmarius ; Arnold 2012, as Axiagastus sp. 003-ARN; this paper); Thailand ( Walker 1867, as A. rosmarus ); Vietnam (this paper).

Nomenclatural note

During the course of this study, another genus of Axiagastini was examined, and the following synonymy is proposed.