Habroloma ( Parahabroloma ) tsutsumiuchii, Tamadera, 2025

Tamadera, Yutaka, 2025, New or little-known jewel beetles on mistletoe, Taxillus Tiegh. (Loranthaceae), in Japan: Unusual morphology and biology in Habroloma Thomson, 1864 (Coleoptera: Buprestidae), Zootaxa 5725 (1), pp. 55-88 : 58-67

Habroloma ( Parahabroloma) tsutsumiuchii sp. nov.

[Japanese name: Oni-hirata-chibi-tamamushi]

Figs. 2A, B , 3–7 , 8A , 13A, B

Description. Male. Body wedge-shaped, rather strongly convex dorsally ( Fig. 3D ). LB 3.85–4.25 mm (mean 4.05 mm; holotype 4.25 mm); WB 2.57–2.83 mm (mean 2.74 mm; holotype 2.83 mm); LB/WB 1.46–1.50 (mean 1.48; holotype 1.50) (n = 10 for all measurements, except for clypeus, trapezoidal plate, and terminalia).

Integument above mainly bronzy-black; elytra sometimes with faint reddish to purplish tints in apical 1/3; underside, antennae, and legs black with weak golden-bronze reflections, except for tarsal pads being pale brown. Dorsal and ventral surfaces moderately shiny. Vestiture mainly consisting of orangish-brown, yellow, white, and black setae; orangish-brown setae predominant, sometimes being yellowish as shown in Fig. 3G . Head densely clothed with short, recumbent orangish-brown setae, with a large bare part on frons, with two inconspicuous whitish spots on vertex. Pronotum unevenly clothed with orangish-brown and white setae which are arranged as follows: 1) a moderate-sized tuft of slightly long, erect setae at middle, becoming darker basally; 2) short, semirecumbent orangish-brown setae mixing with white ones in remaining space except bare parts as shown in Fig. 4A . Elytra unevenly clothed with orangish-brown, yellow, white, and black setae which are complicatedly arranged on each elytron as follows: 1) five tufts of rather long, erect setae: the first tuft situated at postscutellar part and the second at humeral part, the first and second tufts moderate in size, black, becoming orangish-brown basally; just behind middle, the small third tuft situated just mediad of lateral carina, and the smallest fourth just laterad of lateral carina, the third and fourth tufts orangish-brown, the former slightly blackish apically; and in subapical part, the largest fifth tuft, laterally protruding from body outline, black, becoming orangish-brown basally; 2) inverted subtriangular blotch situated just anterior of the third tuft, becoming yellowish anteriorly, mixed with a few white setae posteriorly, laterally connecting with the fourth tuft through a slender, oblique orangish-brown band, which is mixed with a few white setae; 3) first transverse band consisting of orangish-brown and white setae, situated at apical 1/3, zigzag-shaped, weakly wavy, slender; 4) second transverse band consisting of whitish setae, situated at just before the fifth tuft, poorly defined, weakly wavy; 5) orangish-brown setae occurring along sutural margin except near the first tuft, the setose area weakly broadened before the first transverse band; and 6) orangish-brown setae and a few whitish setae scattered in remaining space except for bare parts as shown in Fig. 4A . Underside sparsely setate, with fine, recumbent whitish setae, but hypomeral markings and metacoxal plates laterally with whitish and brownish setae which are rather longer and denser, and apical part of ventrite 5 with longer brownish setae.

Head, when viewed from above, moderately, subtriangularly concave on frons, which is slightly bisinuate, with oculofrontal margins ridged and slightly weakly produced anteriorly. Eyes, when viewed from above, slightly broadly visible, weakly convex laterally. Vertex coarsely variolate-punctate; frons widely concave, distinctly grooved along upper side of midline with a short median line, with surface coarsely variolate-punctate around the bare part which is faintly punctate; supra-antennal pores simply round; clypeus wide, with elevated basal margin and transverse subapical carina, WC/LC 3.17–3.70 (mean 3.52, n = 8; holotype 3.42), WC/LSC 2.64–3.33 (mean 2.91, n = 8; holotype 2.93), arcuately emarginate at apical margin, declivous apicad from the subapical carina ( Fig. 4C ); infra-antennal ridge strongly, triangularly produced ( Fig. 4C ). Antennae ( Fig. 4D, E ) short, not reaching level of widest point of pronotum when laid laterally; scape longer than pedicel, prominently produced outwardly and forming a straight, horn-shaped projection, with apex acutely pointed, the projection sparsely setate with whitish fine setae, usually as long as total length of antennomeres 2–6, but occasionally being shorter (in two specimens collected at Nara, Honshu; Fig. 3G ); pedicel ovate, longer than antennomere 3; 3 subrectangular, longer than 4; 4–6 subrectangular, subequal to each other in length; 7–10 triangular, rather weakly enlarged; 11 sublingulate.

Pronotum widest at sub-basal part, WP/ LP 3.23 – 3.66 (mean 3.47; holotype 3.41), BMP/ AMP 1.91 – 2.04 (mean 1.98; holotype 1.91), wider than elytra; lateral margins evenly arcuately narrowed apicad; apicolateral angles nearly right; basolateral angles sharply acute; apical margin moderately deeply, arcuately emarginate, with very small median lobe; basal margin trisinuate, with median lobe moderately produced; disk weakly depressed laterally, broadly depressed along basal median lobe, with ill-defined basolateral and apicolateral depressions, without pores in the apicolateral depressions; surface coarsely variolate-punctate except the bare parts which are smooth. Scutellar shield small, triangular, glabrous .

Elytra widest at base, LE / WE 1.08 – 1.13 (mean 1.11; holotype 1.13), LE / LP 3.49 – 3.87 (mean 3.72; holotype 3.73); humeral calli weakly developed; lateral margins gradually narrowed posteriorly from base to middle, then more strongly narrowed to near subapical part, and finally strongly convergent to conjointly rounded broad apices, serrated at subapical part with three to five small denticles ( Fig. 4B ), which are hidden under the fifth tufts in dorsal view; epipleura distinctly delimited by distinct marginal carinae occurring from base to subapical part; sutural margin faintly elevated in apical 1/5; lateral carinae occurring from humeri to subapical part, strongly sinuate behind its basal part; disk weakly depressed along lateral half of basal margin on each elytron, constricted behind humeri; surface slightly densely sculptured with deep round punctures which become much larger in basal 1/3 and smaller in apical 1/3 than in median part. Hind wing as shown in Fig. 14A , with distinct anal field which is delimited by anal fold, but without anal embayment; veins MP 3 , MP 4 , and CuA 2 absent, but a slightly long trachea branching from basal part of vein CuA 3+4 present ( Fig. 14B ) .

Underside. Prosternum ( Fig. 4I ) weakly bilobed on apical margin which is distinctly margined; prosternal process wide; trapezoidal plate longer than wide, WTP/LTP 1.22–1.39 (mean 1.30, n = 8; holotype 1.22), WTP/BTP 1.5–1.79 (mean 1.62, n = 8; holotype 1.65), with indistinctly angulate apical corners, with sides which are arcuately dilated posteriorly from narrowest base to beyond basal 1/4 and then more weakly dilated to apical widest part in a rather straight line, with apical margin broadly, weakly arcuate; disk flattened on trapezoidal plate bearing marginal striae along sides, evenly convex on prosternal lobe, which is transversely, shallowly incised at the boundary with trapezoidal plate, with a pair of deep, transverse grooves above procoxal cavities; surface on trapezoidal plate with setiferous pin-prick punctures and ocellate sculptures. Hypomera arcuately, rather shallowly excavated along inner margins near apical angles ( Fig. 4H ), with large, transversely oval hypomeral markings consisting of linear sculptures. Metaventrite moderately variolate-punctate on median portion surrounded by katepisternal suture and moderately variolate on outside of the median portion. Legs with femora and tibiae rather stout; metacoxal plates without arcuate notches on medial posterior margins, moderately produced posteriorly at each lateral angle which is moderately acute angle and usually rounded at apex, with surface moderately variolate; metafemora obtusely angulate at about distal 1/3 of each outer margin; metatibiae without a fringe of spines on each outer margin, but bearing very sparse, short setae throughout the margin; inner tooth of each claw large. Abdominal ventrites with sternal groove only on ventrite 5, which has broadly rounded apex; surface variolate, in ventrite 1 with linearly confluent sculptures near median part.

Male terminalia (n = 3 for measurement). Sternite 9 ( Fig. 5A ; missing in holotype) rather wide, SL/SW 0.90 and 0.94 (n = 2), more or less emarginate at apical margin, without setae. Tegmen ( Fig. 5B ) rather wide; parameres PL/PW 2.88–3.02 (mean 2.94; holotype 3.02), bearing a pair of setae on apicolateral margins, with sides which are subparallel in basal half, then weakly dilated to subapical widest part, and finally arcuately convergent to apices, with shallow dorsal and ventral notches; phallobase PbL/PbW 1.58–1.90 (mean 1.78; holotype 1.87), about 1/5 length of tegmen. Penis ( Fig. 5C, D ) wide, PeL/PeW 4.23–4.56 (mean 4.38; holotype 4.23), shorter than tegmen; dorsal plate with sides (not including sides of median struts) which are subparallel and slightly rounded from base to just beyond middle, and then inwardly arcuately convergent to apex, with distinctly broad apex which is roundly truncate, dorsally with a narrow median groove in apical half but not reaching the apex ( Fig. 5C ), basally with median struts about 1/2 length of penis; ventral plate membranous, but weakly sclerotized as a rather broad, linear patch at middle, rather deeply emarginate apically.

Female. Sexual dimorphism: Antenna with scape which is much more shortly produced outwardly and forming to a short subtriangular projection, of which apex is pointed ( Fig. 4F ), the projection slightly longer than pedicel in length. Measurements: LB 3.45–4.26 mm (mean 4.03 mm, n = 16); WB 2.30–2.84 mm (mean 2.69 mm, n = 16); LB/WB 1.45–1.57 (mean 1.50 mm, n = 16); WC/LC 3.00–3.90 (mean 3.54, n = 11); WC/LSC 2.77–3.36 (mean 3.04, n = 11); WP/LP 3.30–3.73 (mean 3.55, n =16); BMP/AMP 1.83–2.04 (mean 1.95, n = 16); LE/WE 1.10–1.18 (mean 1.12, n = 16); LE/LP 3.64–4.30 (mean 3.87, n = 16); WTP/LTP 1.27–1.47 (mean 1.38, n = 11); WTP/BTP 1.46–1.77 (mean 1.63, n = 11).

Female terminalia (n = 3 for measurement). Ovipositor ( Fig. 5E–G ) short in external part; proctiger with a pair of short, straight baculi at base; coxites transversely subhexagonal, rather sparsely setate on apical margin except middle part; styli short, rather slender, SlL/SlW 4.00–5.50 (mean 4.61), bearing several setae apically; ventral valve without setae; vagina sack-shaped (examined under incompletely inflated state), weakly expanded near opening of spermatheca; spermatheca membranous, rather wide tubular, moderate in length, swollen in apical 3/4, widest at about basal 1/3 of the swollen part, bearing finely strigulate patterns in basal 1/2 of the swollen part, without spermathecal gland.

Differential diagnoses. Habroloma tsutsumiuchii is similar to Habroloma baucis ( Obenberger, 1929) , described from Thailand, in having the similar shaped projection of the male antennal scape (female of the latter species is unknown), the number and arrangement of the pronotal and elytral tufts, the bilobed apical margin of the prosternal lobe, the elytral punctures becoming smaller in the apical half of elytra, and the large-sized body. However, H. tsutsumiuchii is readily distinguished from H. baucis by the following combination of characters: 1) elytral inverted subtriangular blotch of setae much larger ( H. baucis : much smaller and strongly oblique in shape); 2) elytral first tuft (postscutellar tuft) rather larger than the second tuft (humeral tuft) ( H. baucis : the first tuft smaller than the second); 3) elytral first, second, and fifth tufts bicolored into orangish-brown and black ( H. baucis : those tufts being completely black); 4) bronzy-black dorsum ( H. baucis : dark purplish bronze dorsum with apical part of elytra becoming more purplish).

Habroloma tsutsumiuchii is easily distinguished from other Japanese congeners by the modified antennal scape (longer in male than in female), by the presence of a single pronotal tuft and five pairs of elytral tufts, by the bilobed prosternal lobe, and by the apical excavation of the hyomeron.

Type specimens. Holotype ( ♂; missing 8th abdominal segment and sternite 9). “宮¼県綾町綾ṁm | JAPAN: Kyushu |Aya-minami-gawa, Aya-chô , | Higashimorokata-gun, | Miyazaki-ken, 22.VII.2023, |Yuji TSUTSUMIUCHI leg. [white card; printed] || Captured on | Taxillus yadoriki | parasitizing | Castanopsis sieboldii | ( by net sweeping) [white card; printed] || HOLOTYPE ( ♂) | Habroloma ( Parahabroloma) | tsutsumiuchii | det. Tamadera, 2025 [red card; handwritten except for type notation] || NSMT-I-C-200367 [white card; printed]”.

Paratypes ( 9 ♂♂, 16 ♀♀). JAPAN: [Honshu: Nara]— 5 ♂♂ ( Fig. 3B, F–H ), 4 ♀♀ ( Fig. 3I ), Nara-shi, 29.VII.2023, Y. Tamadera leg., captured on Taxillus yadoriki parasitizing Quercus acutissima Carruth. [ Fagaceae ] ( NSMT: NSMT-I-C-200370 ( ♂), -200371 ( ♂), -200372 ( ♂), -200373 ( ♂), -200374 ( ♂), -200375 ( ♀), -200376 ( ♀), -200378 ( ♀), and -200379 ( ♀)); 1 ♂, 1 ♀, same locality, 30.VII.2023, Y. Tamadera leg., emerged on 4.VIII.2023 from T. yadoriki parasitizing Lithocarpus edulis (Makino) Nakai [ Fagaceae ], TaY-149 ( YTJ: 1♂; NSMT: 1 ♀, NSMT-I-C-200380); 2 ♂♂, 3 ♀♀, same locality, 5.IX.2023, H. Fukutomi leg. captured on T. yadoriki (HFCI) ; 1 ♀, same locality, 23.II.2024, Y. Tamadera leg., captured on T. yadoriki parasitizing on Neolitsea aciculata (Blume) Koidz. [ Lauraceae ] ( YTJ); [Kyushu: Miyazaki]— 1 ♀ ( Figs. 2B , 3C ), same locality as holotype, 23.VII.2023, Y. Tsutsumiuchi leg., captured on Castanopsis sieboldii (Makino) Hatus. ex T.Yamaz. et Mashiba subsp. sieboldii [ Fagaceae ] parasitized by T. yadoriki ( NSMT: NSMT-I-C-200368); 1 ♀, same locality as holotype, 26.VII.2023, Y. Tamadera leg., captured on T. yadoriki parasitizing C. sieboldii ( NSMT: NSMT-I-C-200369); 1 ♂, 3 ♀♀, Kitamata, Aya-chô, Higashimorokata-gun, 30.IX.2023, T. Saeki leg., captured on T. yadoriki parasitizing Quercus glauca Thunb. [ Fagaceae ] ( YTJ); 2 ♀♀, same locality, 29.IX.2023, H. Fukutomi leg., captured on T. yadoriki (HFCI) .

Etymology. This new species is named in honor of Yuji Tsutsumiuchi who first collected the species at the type locality.

Distribution. Japan: Honshu ( Nara) and Kyushu ( Miyazaki). See also Fig. 15 .

Biology. Host plant. Loranthaceae : Taxillus yadoriki . Adults feed on the leaves from the lateral margins ( Figs. 6J , 13A ) and tend to stay on the abaxial side of the leaf when feeding ( Figs. 6K , 7A ).

The adults were collected on Taxillus yadoriki parasitizing Castanopsis sieboldii subsp. sieboldii , Lithocarpus edulis , Quercus acutissima , and Q. glauca , and Neolitsea aciculata .

Leaf-mining habit. Mines of H. tsutsumiuchii were found on T. yadoriki parasitizing L. edulis and Q. acutissima by the author (in Nara; Figs. 6 , 13A, B ). Infested leaves were well expanded; multiple mines were found on a single leaf (n = 5); mines were of the full-depth type and each formed an elongate blotch occurring in apical half of the leaf blade, but they were almost invisible from the abaxial side of the leaves because the abaxial leaf surface of T. yadoriki was always covered with dense brownish trichomes. When full grown, multiple mines in a single leaf look like a single large blotch. Two to five eggs, which were black (remaining eggshell + varnish-like substances) and covered with granulate substances which may be adult feces, were laid on near the adaxial surface of the leaf blade near the apex ( Fig. 6A ), except for one example in which only one egg was found on a small leaf. The eggs were laid slightly separated from each other. Each hatched larva mined toward the leaf base, and finally the last (third) instar larva always made a delta-like portion at the terminal part of the mine ( Fig. 6B ). The first and second instar larvae left granular frass inside the mine, and then the last instar made an oval pupal chamber inside the mine with its granular frass ( Fig. 6E–G ). When full grown, the pupal chamber was completely closed. Adults always emerged from the abaxial surface of the leaves with slightly D-shaped exit holes ( Figs. 6C , 13A ).

Habroloma tsutsumiuchii hibernates in the adult stage, as do other congeners in mainland Japan. On 17 February 2024, one female adult was found on the abaxial side of the living host leaf, of which the leaf-margin is weakly curled toward the abaxial side ( Fig. 7B ). After five days, this female was still in the same position in the leaf (on 23 Feb 2024). Insofar as known, the hibernation under the living leaf is the first report of the hibernating site within Habroloma .

Remarks. The holotype of H. tsutsumiuchii is irregularly tinged with blue at parts of the pronotal and elytral bare portions ( Figs. 2A , 3D ), but this coloration was absent when the specimen was initially prepared. This discoloration is probably caused by oil that is seeping out from the body after drying the specimen.

With regard to local variation, the specimens of this new species collected in Miyazaki (Kyushu) tend to show slightly brighter coloration of the dorsal setae and slightly weaker golden-bronze reflections on the pronotum and elytra than specimens collected at Nara (Honshu) ( Figs. 2A, B , 3F–I ). However, these differences are also observed within individuals from the same locality to some extent. Thus, this study concluded that these variations are not significant related to geographic range.

The modified antennal scape of H. tsutsumiuchii is also recognizable in the pupal stage because the corresponding part of the pupal exuvium is distinctly projected ( Fig. 6H, I ).

Figures

FIGURE 2. Dorsal habitus of mistletoe-associated Habroloma spp. A, B: Habroloma (Parahabroloma) tsutsumiuchii sp. nov. (A, male holotype; B, female paratype, Miyazaki); C, D: H. (P.) taxillusi Kato & Kawakita (C, male, Miyazaki; D, female, Miyazaki). Scale bar = 1.00 mm.

FIGURE 3. Habitus of Habroloma (Parahabroloma) tsutsumiuchii sp. nov. A: Holotype, ventral view; B: male in rest position, ventral view (paratype, Nara); C: female paratype, ventral view (paratype, Miyazaki); D: holotype, lateral view; E: holotype, frontal view; F–I: variations in body and setae coloration and in length of projection in male scape (F–H: male; I: female; paratype, Nara). Scale bars = 1.00 mm.

FIGURE 4. Habroloma (Parahabroloma) tsutsumiuchii sp. nov. A: Outline of head, pronotum, and elytron, indicating vestiture arrangement in the left side (holotype); B: serration of elytral lateral margin, left side in obliquely ventral view (holotype); C: clypeus indicated by darker shade area, and its adjacent parts, frontal view (female paratype, Nara); D: male scape, ventral view (holotype); E: male antenna omitting scape, outer side (holotype); F: female scape, ventral view (paratype, Miyazaki); G: female antenna omitting scape, outer side (paratype, Miyazaki); H: hypomeron (part), oblique view; I: prosternum.Abbreviations: hm, hypomeral marking; ir, infra-antennal ridge; lps, length of projection in scape; sp, supra-antennal pore; tp, trapezoidal plate (see the Materials & methods for its definition).

FIGURE 5. Male and female terminalia (part) of Habroloma (Parahabroloma) tsutsumiuchii sp. nov. A: Male sternite 9, dorsal view (paratype, Nara); B: tegmen, dorsal view (holotype); C, D: penis (holotype), dorsal view (C) and ventral view (D; the ventral plate is indicated by darker shade area); E, F: external part of ovipositor omitting proctiger (paratype, Miyazaki), dorsal view (E) and ventral view (F); G: internal part of ovipositor, laterodorsal view (paratype, Nara). Abbreviations: co, common oviduct; cx, coxites; dp, dorsal plate; ms, median strut (s); pa, parameres; pb, phallobase; spm, spermatheca; st, stylus; ts, tegminal strut; vg, vagina; vn, ventral notch; vp, ventral (membranous) plate.

FIGURE 6. Biology of Habroloma (Parahabroloma) tsutsumiuchii sp. nov. A–C: Full-grown mines with five eggs (A, B, adaxial side of leaf) and four adult exit holes (C, abaxial side of leaf), black triangular marks in B indicating the delta-like portion of each mine [Nara, Honshu]; D: two eggs, TaY-149; E–G: a frass pupal chamber (E, adaxial side of leaf; F, lateral; G, horizontal section) [Nara, Honshu]; H, I: a head part of male pupal exuviae (H, dorsal; I, ventral) [Nara, Honshu]; J: female adult feeding on the host leaf [Miyazaki, Kyushu]; K: three adults on abaxial side of leaf [Nara, Honshu]; L: copulation [Nara, Honshu]. Scale bars: D =1 mm; E–G = 5 mm; H, I = 0.5 mm; J, L = 3 mm.

FIGURE 7. Adults of Habroloma (Parahabroloma) tsutsumiuchii sp. nov. in Nara, Honshu. A: An adult on the abaxial side of the host leaf with mines (indicated by a black triangular mark); B: a hibernating female on the abaxial side of the host leaf (17 Feb 2024); C: male antennae in active; D: female antennae in active.

FIGURE 8. Elytral punctures in Habroloma spp. Black triangular marks indicate several non-setiferous punctures.A: Habroloma (Parahabroloma) tsutsumiuchii sp. nov. [paratype: Nara, Honshu]; B: H. (P.) taxillusi Kato & Kawakita [Amami-Ôshima Is., Ryukyus]; C: H. (P.) eximium eximium (Obenberger) [Miyazaki, Kyushu]. Scale bars = 0.25 mm.

FIGURE 13. Taxillus yadoriki leaves infested by Habroloma spp. A: Full-grown four mines of Habroloma (Parahabroloma) tsutsumiuchii sp. nov., with five eggs, four adult exit holes, and adult feeding scars (indicated by black triangular marks) [Nara, Honshu]; B: two mines of H. (P.) tsutsumiuchii sp. nov., with two eggs [Nara, Honshu]; C: mine of H. (P.) taxillusi Kato & Kawakita, with a single egg [Amami-Ôshima Is., Ryukyus]; D: adult feeding scar of H. (P.) taxillusi [Miyazaki, Kyushu]. Asterisks (*) near A and C indicate the abaxial side of the infested leaf, respectively.

FIGURE 14. Hind wings. A, B: Habroloma (Parahabroloma) tsutsumiuchii sp. nov. [paratype; Nara, Honshu]; C, D: H. (P.) taxillusi Kato & Kawakita [Amami-Ôshima Is., Ryukyus]; B, D: trachea branching from basal part of vein CuA3+4, indicated by white triangular marks and traced above with white lines. Scale bars in B, D = 0.10 mm. Abbreviations: CAS, Cubitoanal Spur (vein CuP + AA3); MSP, Medial Spur; RML, Radiomedial Loop.

FIGURE 15. A distribution map of the two Habroloma species, with distribution ranges of the host mistletoe Taxillus yadoriki (broken line) and its Japanese relative T. pseudochinensis (solid line). Study sites in mainland Japan: a, b) Chiba; c) Kanagawa; d) Nara; e) Mie; f) Wakayama; g) Fukui; h) Hyôgo; i) Tottori; j) Kôchi; k) Ôita; l) Miyazaki.