Axiagastus prathapani Salini & Kment, 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 : 52-60

Axiagastus prathapani Salini & Kment sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:EBD3C7F4-ECF6-4FF7-B9F2-E5F83108AD24

( Figs 155–199)

Axiagastus rosmarus (misidentification, partim): Walker (1867): 269 (distribution: Indonesia: Sulawesi); Kirkaldy (1909): 126

(catalogue, distribution: Indonesia: Sulawesi); Arnold (2012): 55 (distribution; Indonesia: Sumatra, Malaysia: Sabah). Axiagastus sp. 001-ARN: Arnold (2012): 55–56 (distribution; Indonesia: Sumatra).

Type locality. Malaysia: Sarawak, Kuching , 1.5534°N, 110.3595°E .

Type material. Holotype: MALAYSIA: Sarawak: ♂, “Kuching [p] / 12.10 [hw] // axiagastus / rosmarus / Dallas [hw]; 1915/136 [hw, reverse] // HOLOTYPUS / Axiagastus prathapani / Salini & Kment sp. nov. // det. Salini, S. & Kment, P., 2024 [red label] // dissected and illustrated Salini. S.” ( BMNH). The specimen is pinned through the scutellum. Antennomeres IIa–IV of both antennae lost, left foreleg broken, protarsus lost, remaining segments (from trochanter to tibia) glued on a card, left mid leg and right hind leg lost except coxae and trochanters, left metatarsus, right protibia and protarsus lost. The dissected male genitalia are placed in a glass microvial with glycerol attached to the same pin.

Paratypes (11♂, 11♀): INDONESIA: Sulawesi: 1♂ , “ INDONESIA / CELEBES [hw, round label, obverse]; 58/142x [hw, reverse] // Axiagastus [hw] / Raphigaster [p] / rosmarus [hw] / Walker’s catal. [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. Right antennomeres IIa–IV lost, left antenna rudimentary and malformed with antennomere I well-developed, and the remaining segments joined to form a short stalk-like structure, one tarsal claw of right foreleg, right metatarsus, left pro- and metatarsus lost, abdomen broken and glued on a card.— 1♀ , “ CELEB [hw] / Wallace [p] // SAUNDERS [p] / 65.13 [p] // mak [hw, round label] // Axiagastus [hw] / Raphigaster [p] / rosmarus [hw] / Walker’s catal. [p]” ( BMNH). Antennomeres III and IV of both antennae lost, one tarsal claw of right foreleg lost, right mesotarsomeres II–III, right metatarsus, left mesotarsus, left and right hemelytra (except exocorium), and right membranous hind wing, lost, antennomeres III–IV, tarsomeres II–III and tarsomeres I–III are glued on white card.— Mentawai Islands : 4♂, 1♀ , “INDONESIA 5. 2004 / SIBERUT isl. / Bojakan, 100m / S. Jakl lgt. [p]” (2♂, 1♀ MMBC; 2♂ NMPC). Specimens card-mounted, 1♂ ( NMPC) with detached genital capsule and dissected paramere glued on the same piece of card.— 1♂, 1♀, “ Coll. I.R.Sc.N.B. / Indonesia, Mentawai isl. / N Siberut Isl. , 150 m / Bojakan vill., v.2004 / leg. St. Jakl / I.G.: 31.127 [p, yellow label]” ( ISNB). Specimen is card-mounted, both antennomeres IV lost .— INDIA: ♂ , “INDIA: Andaman & Nicobar [p]/ North Andaman: Diglipur [p] / 13°14′53.9″ N 92°58′37.5″ E [p]/ 15 mts, 23.iv.2014, at light [p]/ Yeshwanth. H. M. [p] // Axiagastus rosmarus Dallas / Det. C. A. Viraktamath [p] // dissected and illustrated by Salini. S. [p]” ( UASB). The dissected male genitalia are placed in a glass microvial with glycerol attached to the same pin; right antennomere IV glued on a card, left antennomere IV lost. — 1♀ , “INDIA: Tripura [p] / Shanmura [p] / 29.xii. 2006 [p] / J. Das [p] // B. K. Agrawala College [p] / Tripura University [p] // NBAIR/Pent-36/2016 [p] // 36 [p] // Het/Pent 513 [p] / Ex. Mustard. // dissected and illustrated by Salini. S. [p]” ( NIM). 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 .— LAOS: 1♂ , “LAOS, Salavan prov., Xe Xap NPA, / ca. 15km NE of Ta-oy, BAN DOUB env. / 16°08´N /106°40-43´E, 400- 1000 m / 25.-31.V.2012; M. Brancucci, M. Geiser, / K. Phanthavong & S. Xyalath lgt. / NMB Laos Expedition 2012 [p] ( NHMB). Specimen card-mounted, detached genital capsule and one paramere glued on the same piece of card.— MALAYSIA: Johor: 1♀, “Gunong Prati / Johore [hw] / Aug. [p] 14. [hw] 19[p]21[hw] / V. / Knight [hw] Coll. [p] // Ex F.M.S. / Museum / B.M. 1955-354 [p] // ♀ [p]” ( BMNH).— Selangor: 1♀ , “ Malaya [p] / Kuala Lumpur [hw] / 29.ix.1937 [hw] / H. T. Pagden [p] // dissected and illustrated Salini. S. [p] // Brit. Mus. [p] / 1954–706 [p]” ( BMNH). 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, left antenna broken and left antennomeres IV lost, left antennomeres I–III glued on a card, right antennomeres III–IV, left mesotarsus and right mesotarsomeres II–III lost.— 1♀ , “ Malay Penin : / Ex. Coll. Agr. Dept. / Kuala Lumpur / July 6 th 1918 / C. B. Hunt [hw] // Ex F.M.S. / Museum / B.M. 1955-354 [p] // Axiagastus / rosmarus / Dall. [hw] // ♀ [p]” ( BMNH); 1♀ , “MALAY PENIN: / Selangor / Bukit Kutu [p] / at light 3300 [hw] ft [p] / 28. 9. [hw] 19[p]32[hw] H. M. Pendelbury. [p] // Ex F.M.S. / Museum / B.M. 1955-354 [p] // ♀ [p]” ( BMNH).— Sabah: 1♂ , “ Malaysia, Sabah, North / Borneo / District Ranau / Poring Hot Spring / LF, Poring Lodge [p] // 06°02′35 N / 116°42′19 E / ca. 650 müNN [= m a.s.l.], / lgt. 14 - 16.V.2002 / T. Kothe [p] // Axiagastus / rosmarus / DALLAS, 1851 [p] // det. ARNOLD 200[p]6[hw]” ( ZSMC). The specimen is pinned through the scutellum, hemelytra partly outstretched, right antennomere IV and right fore leg lost; detached genital capsule and one dissected paramere glued on a piece of card attached to the same pin.— 1♂ , “ Malaysia, Sabah, North / Borneo / District Ranau / Poring Hot Spring / LF, Poring Lodge [p] // 06°02′35 N / 116°42′19 E / ca. 650 müNN [= m a.s.l.], / leg. 14 - 16.V.2002 / T. Kothe [p] // Axiagastus / rosmarus ♂ / DALLAS, 1851 [p] // det. ARNOLD 200[p]6[hw]” ( ZSMC). The specimen is pinned through the scutellum, right antennomeres III and IV lost .— Sarawak: 1♀ , “MALAYSIA, Sarawak / 10 - 19 March 1994 / Kapit distr. , Sebong env. / P. Bílek lgt., Baleh riv. [p] // EX COLLECTIO / Z. JINDRA, PRAGUE [p]” ( ZJPC). Specimen card-mounted, left mesotarsomere III lost.— 1♂ , “ SARAWAK: [p] / Kuching / 12.12 [hw] / J.M.Bryan / B.M.1931-150. [p] // Kuching. [p] / 12.12 [hw] // DISSECTED & / ILLUSTRATED / SALINI. S. 2023 [hw] // ♂ [p]” ( BMNH). Dissected male genitalia in glass microvial attached to the same pin .— SINGAPORE: 1♀ , “ ♀ [p] // Singapore / H. N. Ridley / 1902-205. [p]” ( BMNH); 1♀ , “gardens / Singapore [hw] / Nov. 19[p]22[hw] / J.N. [?] / Chasen [hw] Coll. [p] // Ex F.M.S. / Museum / B.M. 1955-354 [p] // ♀ [p]” ( BMNH).—Each specimen bears the following identification label : “ PARATYPUS / AXIAGASTUS PRATHAPANI / Salini & Kment sp. nov. / det. Salini, S. & Kment, P., 2024 [p, yellow label].

Additional material examined. INDONESIA: Sumatra: 1♀, “ 9.–29.X.1991 / W– Sumatra / Payakumbuh / Harau –Vall., 1000m / leg. A. Riedel [p] // Axiagastus ♀ / rosmarus / DALLAS, 1851 [hw] / det. ARNOLD 200[p]6[hw]” ( ZSMC) ; 1♀, “ Sumatra Holzweg / 2/ 4, 1150 m, / Simalungun, / leg. 13. X.1996 / E. W. DIEHL [p] // Axiagastus ♀ [hw] / det. ARNOLD 200[p]6[hw]” ( ZSMC; Fig. 158) ;— Java: 1♀, “ Java: West Java, S. Bantam / Bajah , 300 ft / M. E. Walsh lgt. // P. Kment det.” ( NHMB) . Due to the existing variation in colouration and lack of associated males the identification of these three females is only tentative.

Description. Colour, integument and vestiture ( Figs 155–163). Body colour appearing black due to dense, coarse, black punctation; head with longitudinal stripes along lateral margins of clypeus black; dense, black punctation arranged as longitudinal rows on dorsum of head; antennae with each scape (I) and basipedicellite (IIa) ochraceous, distipedicellite (IIb) and basiflagellum (III) black with base narrowly ochraceous, distiflagellum (IV) black or sometimes with base and apex black, pale white medially; pronotum variable with coarse, black punctures; anterior pronotal disc with punctures confluent to form small, more or less round black spots arranged equidistantly in two rows (the posterior one sometimes indistinct); black punctation denser, confluent on posterior disc, forming narrow to wide transverse black stripe along posterior margin of pronotum, usually not extending laterad of anterolateral angles of scutellum; markings and punctation on scutellum variable; in palest specimens, ground colour of coria luteous with dark brown to black, coarse, densely distributed punctures, apex of scutellum with dark, wide transverse anteapical stripe, and whitish, impunctate, transversely oval apical spot (slightly notched anteromedially) ( Fig. 158); in most specimens, prefrenal portion of scutellar disc with 1+1 small submedial stripes on anterior margin, and 1+1 larger submedial spots in center of disc ( Figs 155‒159); in dark specimens, dark spots on prefrenal portion of scutellar disc large, more or less confluent ( Fig. 155); connexiva luteous with anterior and posterior fourths of each connexival segment, including posterolateral angles, black; punctures fine, black, densely distributed on anterior and posterior fourths of connexival segments, middle half of connexival segments with punctures fine, brown, densely distributed; coria variable, from mostly pale with scattered black punctures to mostly dark, with one small, pale callose spot laterally on middle of each endocorium; membranes smoky brown. Ventral surface of body with luteous, coarse, dark brown or black punctures densely distributed on ventral surface of thoracic sternites and abdominal ventrites, confluent, forming transverse broken stripes, especially on thoracic sternites; head on ventral surface with black punctures restricted along longitudinal black stripe on either side of bucculae, apices of each buccula or sometimes near base of each antenna; abdomen on ventral surface with coarse, black punctures densely distributed; intersegmental sutures of ventrites III–VII reinforced with black transverse stripes; apices of buccular denticles, labium, ostiolar peritremes and tarsal claws, one spot each at base of pro-, meso-, and metacoxae, and one spot each at lateral ends of muscle scars on ventrites III–VII forming a row sublaterally on either side, one spot each at middle of lateral margin of pro-, meso- and metapleuron, a moderately large spot mesad to each spiracle but coalescing with spiracular margin anteriorly, short, narrow, transverse stripe at antero- and posterolateral angles, black. Legs concolourous with ventral surface of abdomen with dense, coarse, black punctation; femora with punctures appearing as moderately large black spots and punctures on tibiae small, dorsal surface of tibiae with longitudinal ridges black.

Structure. Labium long, length variable, reaching ventrite IV to VI. Other characters as in generic redescription.

Male genitalia ( Figs 164, 166–196). Genital capsule ( Figs 166–169, 173–176, 180–183, 187–190) subquadrate, dorsal rim more deeply incised than ventral rim; lateral wall of dorsal rim obliquely straight, sclerotized black border with minute, distinct serrations (sr) contiguous with shallow, transverse emargination (te) at middle of dorsal rim; dorsal sinus of posterior aperture broadly U-shaped (ds), ventral margin of posterior aperture semiovate; ventral rim including posterolateral angles bordered with moderately developed setae on posterolateral lobes; posterolateral lobes with a broad angulation (a) in lateral view ( Figs 169, 176, 183, 190); ventral rim wavy, moderately concave at middle ( Fig. 187); infoldings of ventral rim deeply impressed on either side of the moderately developed distension (dn) at middle, distension (dn) sunken, emarginated with shallow, V-shaped incision at middle; infoldings of ventral rim laterally (mesad to posterolateral lobes) with a narrow sclerotized, black ridge with distinct sawtooth-like projections (sp) ending in short, blunt, apically rounded denticles (dt). Paramere ( Figs 170–172, 177–179, 184–186, 191–193) simple, crown lanceolate with apex abruptly narrowed, acuminate in lateral view ( Figs 172, 178, 179, 185, 186, 192, 193), dorsal margin (dm) uniformly convex, inner side of crown cushion-like with fine, minute setae; elongate setae along periphery of laminate disc (ld); stem moderately elongate, apodeme disc-like. Phallus ( Figs 194–196) nearly as in Axiagastus chandrashekarai Salini, Kment & Roca-Cusachs sp. nov., with articulatory apparatus as in Figs 194‒196; processes of aedeagus elongate, as shown in Fig. 196.

Female genitalia ( Figs 197–199). Terminalia ( Figs 197, 198). Valvifers VIII as in A. chandrashekarai Salini, Kment & Roca-Cusachs sp. nov.; valvifers IX short, narrow, transverse plate, anterior and posterior margins nearly straight; laterotergites IX elongate, apically rounded, reaching caudal margin of abdomen; laterotergites VIII short, subtriangular, lateral margins convex, caudal margins, each with a minute sclerotized denticle. Gynatrium and spermatheca ( Fig. 199) as in A. chandrashekarai .

Differential diagnosis. This species can be differentiated by the two rows of black spots which are arranged equidistantly on the anterior pronotal disc (the posterior row sometimes obscure), the broadly oval whitish spot on the apex of the scutellum, and the antennae bicolourous, scape (I) and basipedicellite (IIa) mostly pale, distipedicellite (IIb) to distiflagellum (IV) black. Also, the male genitalia offer distinguishing characters, such as the shape of the parameres and the processes of the aedeagus. Axiagastus prathapani sp. nov. is similar in colouration to A. votypkai sp. nov., especially in the pattern of the scutellar spots, but differs from the latter in having darker antennae (mainly pale antennae in A. votypkai ).

Etymology. This new species is named in honor of the first author’s (SS) professor, Kaniyarikkal Divakaran Prathapan (College of Agriculture, Vellayani, Kerala Agricultural University, Thiruvananthapuram, Kerala, India) in recognition of his numerous contributions to the taxonomy of the Coleoptera and for guiding the first author on several occasions. The species-group name is a noun in the genitive case.

Distribution. India: Andaman and Nicobar Islands (this paper), Tripura (this paper); Indonesia: Java (this paper), Mentawai Islands (this paper), Siberut (this paper), Sulawesi ( Walker 1867, as A. rosmarus ), Sumatra ( Arnold 2012, as A. rosmarus and Axiagastus sp. 001-ARN; this paper); Laos (this paper); Malaysia: Johor (this paper), Sabah ( Arnold 2012, as A. rosmarus ; this paper), Sarawak (this paper), Selangor (this paper); Singapore (this paper).