Axiagastus mitescens Distant, 1901

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 : 47-52

Axiagastus mitescens Distant, 1901

( Figs 134–154)

Axiagastus mitescens Distant, 1901: 586 (original description, distribution). Syntypes: China: Hainan Island (BMNH).

Axiagastus mitescens : Bergroth (1908): 172 (catalogue, distribution); Kirkaldy (1909): 126 (catalogue, distribution); Kirkaldy (1910): 106 (checklist, distribution); Hoffmann (1932a): 8 (checklist); Hoffmann (1932b): 139 (listed); Wu (1933): 216 (checklist); Hoffmann (1935a): 75 (catalogue, distribution); Tang (1935): 335 (catalogue); Stichel (1961): 764 (checklist); Stichel (1962): 244 (checklist); Hsiao & Zheng (1977): 90, figs 416–417 (morphological illustrations), 132 (diagnosis), Pl. 17: fig. 234 (habitus photograph); Chen et al. (1985): 47 –48 (distribution); Hua (1989): 43 (list); Zhang (1995): 42, Pl. XII: fig. 114 (redescription, distribution, habitus illustration); Hua (2000): 171 (checklist, plant association, distribution); Rider et al. (2002): 137 (checklist, distribution); Rider (2006): 260 (catalogue, distribution); Fan (2011): 71 –73, figs 2.29 a–g (key to species, redescription, drawings of male and female genitalia, distribution), 559–560, figs 62–63 (habitus photographs in dorsal and ventral view).

Type locality. China, Hainan Island .

Type material. Syntypes (3♂, 14♀): CHINA: Hainan : 1♀, “ HAINAN / ISLAND [p] // Type [p, red-margined disc // mitescens / Dist. [hw] // Distant Coll. / 1911–383 [p] // ♀ [p] // [QR code] / NHMUK010582892 [p]” ( BMNH) ; ♀, “ HAINAN / ISLAND [p] // SYNTYPE [p, blue-margined disc] // Distant Coll. / 1911–383 [p]” ( BMNH); ♀, HAINAN / ISLAND [p] // SYNTYPE [p, blue-margined disc] // Axiagastus mitescens Distant // Distant Coll. / 1911–383 [p] // NHMUK 013589098 [p]” ( BMNH) ; 1♀, “ Hainan [hw] // Distant Coll. / B. M. 1911-383 [p] // ♀

[p]” ( BMNH); 1♀, “ Hainan / Island [hw] // Distant Coll. / B. M. 1911-383 [p] // ♀ [p]” ( BMNH) ; 9♀, “ Distant Coll. / B. M. 1911-383 [p] // ♀ [p]” ( BMNH) ; 3♂, “ Distant Coll. / B. M. 1911-383 [p] // ♂ [p]” ( BMNH) .— Each specimen bears the following identification label: “ SYNTYPUS / AXIAGASTUS MITESCENS / Distant, 1901 / des. Salini, S. & Kment, P., 2024 [p, red label] .

Redescription. Colour, integument and vestiture ( Figs 134–139). Body above (except hemelytra) orange yellow, with following well-expressed black markings: longitudinal stripes on disc of head along lateral margins of clypeus, extending to posterior margin of head, anterolateral margins of pronotum, transverse (sometimes broken) stripe posteriorly on pronotal disc, 1+1 moderately large, submedian spots at one-third from base of scutellar disc, broad lunulate median spot at one-third from apex of scutellar disc; disc of head dorsally with fine, black punctures arranged in one or two longitudinal rows, disc of pronotum with coarse, black punctures sparsely distributed, sometimes coalescent to form small, black spots, especially on anterior pronotal disc; ground colour of each clavus and corium yellowish, with dense, coarse, black punctures arranged on each corium, punctures finer on exocorium; scape pale, concolourous with body, remaining antennomeres black; connexiva concolourous with body; membranes smoky brown; ventral surface of body concolourous with dorsum, head on ventral surface impunctate; black, coarse punctures on thoracic sternites; ventrites impunctate; apices of ostiolar peritremes, labium, and tarsal claws, a moderately large spot coalescent with each spiracle anteriorly, a row of small spots mesad to lateral margins of abdomen, small denticle on posterolateral angle of each abdominal segment, black; legs concolourous with ventral surface of body, impunctate, sometimes with one or two small, black, more or less round spots on femora.

Structure. Labium short, reaching metacoxae. Other characters as in generic redescription.

Male genitalia ( Figs 140, 142–151). Genital capsule ( Figs 142–145) subquadrate, dorsal rim more deeply incised than ventral rim; lateral wall of dorsal rim slightly concave, few minute, indistinct serrations (sr), appearing sclerotized black, ending in moderately developed angulation contiguous, with deep, transverse emargination (te) on middle of dorsal rim; dorsal sinus of posterior aperture broadly U-shaped (ds), ventral margin of posterior aperture semispherical; setae bordering ventral rim absent, unlike in other species, moderately developed setae on posterolateral lobes, and short fine setae mesad to median distension; ventral rim moderately concave at middle (vr), slightly concave sublateral to posterolateral lobes; posterolateral lobes with minute angulations, in lateral view; infoldings of ventral rim deeply impressed on either side of moderately developed distension at middle, distension (dn) sunken, with short emarginate V-shaped incision at middle, visible on dorsal view of genital capsule; infoldings of ventral rim laterally (inner to posterolateral lobes) with a prominent, obtuse or blunt, sclerotized, black denticle (dt). Paramere ( Figs 146–148) simple, crown finger-like, as in A. yeshwanthi sp. nov., with dorsal margin convex at one-third in lateral view ( Figs 146, 147); finger-like crown on inner side with numerous fine, short setae, single moderately elongate setae on dorsal side; elongate setae along periphery of laminate disc (ld); crown gradually narrowed towards apex; apex rounded, not acuminate in lateral view ( Figs 146, 147); stem moderately elongate, apodeme disc-like. Phallus ( Figs 149–151). Articulatory apparatus as in Figs 149‒151; phallotheca less sclerotized, distal part transparent, with ventral convex projection (vcp) in close proximity with processes of aedeagus (pa); a pair of dorsal conjunctival processes (cp), partly sclerotized throughout length, apically rounded; aedeagus (ad) short, deflected dorsad, apex swollen, drop-like, transparent, with embedded phallotreme, processes of aedeagus much elongate and as shown in Fig. 151.

Female genitalia ( Figs 141, 152–154). Terminalia ( Figs 141, 152, 153). Valvifers VIII as in A. cambelli ; valvifers IX short, narrow, transverse plate, anterior margin of each angulate at middle, posterior margins slightly concave; laterotergites VIII and IX as in A. rosmarus . Gynatrium as in A. rosmarus . Spermatheca ( Fig. 154) as in A. rosmarus , distal spermathecal duct gradually widened towards proximal flange, slightly wider than intermediate part of spermatheca; apical receptacle small, with three ductules; a pair of short, subequal (one with short branch before apex), third one slightly longer.

Differential diagnosis. This robust species is the only known species of Axiagastus with a unique orange-yellow dorsal body colour with well-expressed black markings, especially on the scutellar disc, and the lack of a yellowish, impunctate spot on the apex of the scutellum. This species can also be distinguished by differences in the male genitalia structures, such as the shape of the paramere and processes of the aedeagus.

Plant association. Fagaceae ( Zhang 1995, Hua 2000).

Etymology. Although the original publication did not specify the gender or the etymology, the specific name “ mitescens ” is the present participle in the nominative singular of the verb “ mitesco ”, meaning “to become mild or mellow”. It is invariable.

Distribution. China: Fujian ( Chen et al. 1985, Hua 2000, Rider et al. 2002, Fan 2011), Guangdong ( Wu 1933, Rider et al. 2002, Fan 2011, no exact records), Hainan ( Distant 1901, Hsiao & Zheng 1977, Fan 2011).

The record from Guangdong ( Wu 1933) may refer to Hainan, as that island was previously part of Guangdong (cf. Hsiao & Zheng 1977). It has also been reported to be distributed in Myanmar, Philippines and Thailand ( Hsiao & Zheng 1977), however, we did not find any specimens or published records to confirm this.

Remarks. This species was originally described from an unspecified number of specimens (syntypic) with data: “ Hainan Island”. The range of measurements, from “ 13 to 14 mm ”, indicates that more than one specimen was examined, and although the fifth joint was noted as “mutilated”, this condition is consistent across all specimens.