2 ♂♂, labeled ‘Thailand: Nan prov. Doi Phuka Nat. Park, 28.IV-12.V.2002, Průdek & Obořil lgt.’ (MHNG); 1 ♂, labeled ‘THAI, 28–31.v.1995, 19.27N, 98.20E, SOPPONG 1500 m, Vit Kubáň leg.’ (MHNG).

Horniella aculeata is readily recognizable by the presence of a large spine on the mesal margin of the protibiae (Yin and Li 2015: fig. 2F), and the aedeagus with one elongate, twisted sclerite (Yin and Li 2015: fig. 2K). This species was described based on two male and four female specimens from Yunnan, China, and the present record extends its distribution to Thailand.

China: Yunnan; Thailand: Nan, Mae Hong Son. New country record for Thailand.

Holotype: Thailand: ♂, ‘THAILAND: Chiang Mai, Pinh Khong env. 900 m, 19°26.70'N, 99°01.9'E, 14.xi.2012, M. Košťál lgt.’ (MHNG). Paratype: Thailand: 1 ♀, same label data as for holotype (MHNG).

Figure 1. 

Dorsal habitus of Horniella species A H. bifurca sp. nov. B H. haucki sp. nov. Scale bars: 1 mm.

Male. Head approximately as long as wide, with distinct anterolateral genal projection, anterior margin of projection roundly emarginate; with long, apically forked ocular canthus; scape angularly expanded at anterolateral margin, antennomeres 9–11 moderately enlarged. Pronotum rounded at anterolateral margins. Protrochanter and profemur each with long ventral spine; protibia with small triangular apical spur; mesotrochanter with short but distinct ventral spine. Tergite 1 (IV) with median carina extending posteriorly for approximately 1/4 of tergal length, discal carinae long and thick. Aedeagus with asymmetric median lobe, right half of median lobe greatly protruding apicad, left half strongly curved and forked at apex; endophallus composed of two elongate, twisted sclerites.

Female. Similar to male in external morphology, profemur each with two ventral spines near base, protibia lacking preapical spur, mesotrochanter lacking ventral spine; genital complex as in Fig. 10A.

Male. Body reddish-brown, length 3.35 mm. Head (Fig. 2A) approximately as long as wide, HL 0.69 mm, HW 0.7 mm; anterolateral genal projection distinct, anterior margin of projection roundly emarginate; antenna 1.7 mm long, scape angularly expanded at anterolateral margin, antennomeres 2–8 slightly elongate or moniliform, club loosely formed by apical three moderately enlarged antennomeres, antennomere 11 largest, approximately as long as antennomeres 9 and 10 combined; indistinct lateral postantennal pits present; eyes prominent, each composed of approximately 45 large facets, with long, broad forked ocular canthi (Fig. 2B).

Figure 2. 

Diagnostic characters of Horniella bifurca sp. nov. A left half of head, in dorsal view B head, in lateral view C protrochanter and profemur D protibia E mesotrochanter and mesofemur F mesotibia G–I aedeagus, in dorsal (G), lateral (H), and ventral (I) view. Scale bars: 0.3 mm (A, C–F); 0.2 mm (B, G–I).

Pronotum as long as wide, PL and PW 0.67 mm, widest at apical 1/3; anterolateral margins rounded; disc moderately convex, finely punctate, with distinct median antebasal and lateral antebasal foveae connected by complete transverse sulcus.

Elytra much wider than long, EL 0.91 mm, EW 1.36 mm; each elytron with two large, setose basal foveae; discal striae extending from outer basal foveae to apical 3/4 of elytral length.

Legs elongate; protrochanter (Fig. 2C) with elongate ventral spine, profemur (Fig. 2C) with long ventral spine near base, protibia (Fig. 2D) with small triangular apical spur; mesotrochanter (Fig. 2E) with short but distinct ventral spine, mesofemur (Fig. 2E) and mesotibia (Fig. 2F) simple.

Abdomen slightly broader than long, broadest at lateral margins of tergite 1 (IV), AL 1.08 mm, AW 1.22 mm; tergite 1 (IV) largest, as long as tergites 2 and 3 (V and VI) combined, with short median carina extending to near basal 1/4 of tergal length, discal carinae long and thick, with broad basal impression, tergite 2 (V) lacking carina, tergites 2–4 (V–VII) each with small basolateral foveae. Sternite 2 (IV) with broad basal sulcus, lacking mediobasal foveae, basolateral foveae developed as large cuticular pockets, with two pairs of antebasal protuberances, sternites 3–5 (V–VII) each with basolateral foveae, and one median and two lateral nodules, sternite 7 (IX) with well-sclerotized apical half and membranous basal half.

Aedeagus (Fig. 2G–I) 0.61 mm long, with asymmetric median lobe, right half of median lobe greatly protruding apicad, left half elongate, with strongly curved and deeply forked apical part; endophallus composed of two elongate, twisted sclerites.

Female. General morphology similar to male, each eye composed of approximately 30 facets; profemur with two long ventral spines near base, protibia lacking preapical spur, mesotrochanter lacking ventral spine. Measurements (as for male): BL 3.08 mm, HL 0.68 mm, HW 0.61 mm, PL 0.65 mm, PW 0.63 mm, EL 0.79 mm, EW 1.17 mm, AL 0.96 mm, AW 1.2 mm. Genital complex (Fig. 10A) with transverse apical sclerite, and elongate membranous basal portion.

This species is placed as a member of the H. centralis group. It can be readily separated from the other members of the group by the long, apically-forked ocular canthi, as well as by the unique shape of the aedeagus.

Thailand: Chiang Mai.

The new specific epithet bifurca (-us, -um) is a Latin adjective means ‘two-pronged’, referring to the apically-forked ocular canthus of the new species.

Holotype: Thailand: ♂, ‘THAI, N, Mae Hong Son prov., SE of Soppong, 1500 m, 19°27'N, 98°20'E, 23–27.v.1999, D. Hauck leg.’ (MHNG).

Male. Head longer than wide, with distinct anterolateral genal projection, anterior margin of projection roundly emarginate; with long ocular canthus; scape angularly expanded at basolateral margin, antennomeres 9–11 moderately enlarged. Pronotum rounded at anterolateral margins. Protrochanter and profemur each with long ventral spine; protibia strongly curved near apex, with long apical projection; mesotrochanter with large sharp ventral spine, mesofemur distinctly arched. Tergite 1 (IV) with median carina extending posteriorly for approximately 3/4 of tergal length, discal carinae short and thin. Aedeagus with asymmetric median lobe, left half of median lobe greatly protruding in dorso-ventral view; endophallus composed of three long sclerites.

Male. Body reddish-brown, length 3.49 mm. Head (Fig. 3A) slightly longer than wide, HL 0.75 mm, HW 0.7 mm; anterolateral genal projection distinct, anterior margin of projection roundly emarginate; antenna 1.95 mm long, scape angularly expanded at basolateral margin, antennomeres 2–7 slightly elongate, antennomere 8 as long as wide, club loosely formed by apical three moderately enlarged antennomeres, antennomere 11 largest, approximately as long as antennomeres 9 and 10 combined; indistinct lateral postantennal pits present; eyes prominent, each composed of approximately 40 large facets, with long ocular canthi (Fig. 3B).

Figure 3. 

Diagnostic characters of Horniella haucki sp. nov. A left half of head, in dorsal view B head, in lateral view C protrochanter and profemur D protibia E mesotrochanter and mesofemur F mesotibia G–I aedeagus, in dorsal (G), lateral (H), and ventral (I) view. Scale bars: 0.3 mm (A, C–F); 0.2 mm (B, G–I).

Pronotum longer than wide, PL 0.74 mm, PW 0.69 mm, widest at apical 1/3; anterolateral margins rounded; disc moderately convex, finely punctate, with distinct median antebasal and lateral antebasal foveae connected by complete transverse antebasal sulcus.

Elytra much wider than long, EL 0.95 mm, EW 1.35 mm; each elytron with two large, setose basal foveae; discal striae extending from outer basal foveae to apical 2/3 of elytral length.

Legs elongate; protrochanter (Fig. 3C) with distinct ventral spine, profemur (Fig. 3C) with long ventral spine near base, protibia (Fig. 3D) strongly curved near apex, with long apical projection; mesotrochanter (Fig. 3E) with long sharp ventral spine, mesofemur (Fig. 3E) strongly arched at middle, mesotibia (Fig. 3F) strongly curved near apex, with small triangular spur.

Abdomen slightly broader than long, broadest at lateral margins of tergite 1 (IV), AL 1.05 mm, AW 1.32 mm; tergite 1 (IV) largest, as long as tergites 2 and 3 (V and VI) combined, with median carina extending to near basal 3/5 of tergal length, discal carinae short and thin, tergite 2 (V) lacking carina, tergites 2–4 (V–VII) each with small basolateral foveae. Sternite 2 (IV) with broad basal sulcus, lacking mediobasal foveae, basolateral foveae developed as large cuticular pockets, with two pairs of antebasal nodules, sternites 3–5 (V–VII) with basolateral foveae, one median and two lateral nodules, sternite 7 (IX) with well-sclerotized apical half, and membranous basal half.

Aedeagus (Fig. 3G–I) 0.69 mm long, with asymmetric median lobe, left half of median lobe greatly protruding in dorsal view; endophallus composed of three elongate sclerites close to each other.

Female. Unknown.

This new species can be readily separated from all members of the H. centralis group primarily by the characteristic shape of the aedeagus, especially the form of the apical portion of the median lobe, and the configuration of the endophallus.

Thailand: Mae Hong Son.

The new species is named after David Hauck (České Budějovice, Czech Republic), collector of the holotype.

Holotype: India: ♂, ‘INDIA, Meghalaya State (7+9), E Khasi Hills, 11km SW Cherrapunjee, Laitkynsew, 25.iv.2008, 25°12'48"N, 91°39'48"E, 735 m, Fikáček, Podskalská, Šípek lgt. / secondary tropical rainforest with young trees + bamboo, below village, thin layer of leaf litter (sifting).’ (MHNG).

Figure 4. 

Dorsal habitus of Horniella species A H. khasiensis sp. nov. B H. nantouensis sp. nov. Scale bars: 1 mm.

Male. Head wider than long, with distinct anterolateral genal projection, anterior margin of projection roundly emarginate; with markedly long ocular canthus; scape angularly expanded at middle of lateral margin, antennomeres 9–11 enlarged. Pronotum rounded at anterolateral margins. Protrochanter and profemur each with long ventral spine; mesotrochanter with short, small ventral tubercle. Tergite 1 (IV) with median carina extending posteriorly for approximately 1/4 of tergal length, lacking discal carinae, tergite VIII with large medioapical process. Aedeagus with slightly asymmetric median lobe, apex broadly truncate in dorso-ventral view; endophallus composed of three sclerites.

Male. Body reddish-brown, length 2.84 mm. Head (Fig. 5A) wider than long, HL 0.56 mm, HW 0.63 mm; anterolateral genal projection distinct, anterior margin of projection roundly emarginate; antenna 1.85 mm long, scape angularly expanded at middle of lateral margin, antennomeres 2–8 slightly elongate or moniliform, club loosely formed by apical three moderately enlarged antennomeres, antennomere 11 largest, slightly shorter than antennomeres 9 and 10 combined; indistinct lateral postantennal pits present; eyes prominent, each composed of approximately 40 large facets, with markedly long and curved ocular canthi (Fig. 5B).

Figure 5. 

Diagnostic characters of Horniella khasiensis sp. nov. A left half of head, in dorsal view B head, in lateral view C protrochanter and profemur D protibia E mesotrochanter and mesofemur F mesotibia G–I aedeagus, in dorsal (G), lateral (H) and ventral (I) view. Scale bars: 0.2 mm (A–I).

Pronotum as long as wide, PL and PW 0.64 mm, widest anterior to middle; lateral margins rounded; disc moderately convex, finely punctate, with distinct median antebasal and lateral antebasal foveae connected by complete transverse antebasal sulcus.

Elytra much wider than long, EL 0.75 mm, EW 1.2 mm; each elytron with two large, setose basal foveae; discal striae extending from outer basal foveae to near posterior margin of elytra.

Legs elongate; protrochanter (Fig. 5C) with elongate ventral spine, profemur (Fig. 5C) with conspicuously long ventral spine near base, protibia (Fig. 5D) simple; mesotrochanter (Fig. 5E) with short and small ventral tubercle, mesofemur (Fig. 5E) and mesotibia (Fig. 5F) simple.

Abdomen broader than long, broadest at lateral margins of tergite 1 (IV), AL 0.89 mm, AW 1.21 mm; tergite 1 (IV) largest, as long as tergites 2 and 3 (V and VI) combined, with short median carina extending to near basal 1/4 of tergal length, lacking discal carinae, tergite 2 (V) lacking carina, tergites 2–4 (V–VII) each with small basolateral foveae, tergite 5 (VIII) with large medioapical process. Sternite 2 (IV) with broad basal sulcus, lacking mediobasal foveae, basolateral foveae developed as large cuticular pockets, with two pairs of antebasal nodules, sternites 3–5 (V–VII) with basolateral foveae, one median and two lateral nodules, sternite 7 (IX) nearly oval, with well-sclerotized apical half and less sclerotized basal half.

Aedeagus (Fig. 5G–I) 0.59 mm long, median lobe nearly symmetric, apex broadly truncate; endophallus composed of three sclerites: one elongate, plate-like sclerite with curved lobe at apex; one curved sclerite at base, and one much narrower sclerite at left.

Female. Unknown.

This species is placed as a member of the H. burckhardti group, and is most similar to H. hongkongensis Yin & Li in having similar spination of the legs and a general aedeagal form. They can be clearly separated by the more distinctly expanded basolateral margin of the scape, tergite VIII with a large medioapical process, and the different structure of the aedeagal endophallus.

India: Meghalaya.

The new species is named after its type locality, the East Khasi Hills.

Holotype: China: ♂, ‘TAIWAN: Nantou County, Huisun Forest Reserve [惠荪林场], track to Xiaochushan Mt., 24.0745N, 121.0366E; 1150 m, 4.v.2019; Damaška, Fikáček, Hu & Liu lgt., 2019-TW14 / primary forest on the slope with sparse understory; sifting of small accumulations of leaves / Huisun Leaf Litter Beetles Project, Additional specimen: HS1-034 / HORNIELLA sp., P. Hlaváč det., 2019’ (NMNS). Paratypes: China: 1 ♀, same data as holotype, except ‘Huisun Leaf Litter Beetles Project, Additional specimen: HS1-035’ (NMNS); 1 ♀, ‘same locality and date, except ‘24.0826N, 121.0316E; 1050 m, 2019-TW15’ / sparse secondary forest with dense understory incl. tree ferns on the margin of a tree plantation: sifting / Huisun Leaf Litter Beetles Project, Additional specimen: HS2-041’ (NMNS); 1 ♂, ‘Tehuashe (900 m), Nantou, Taiwan, 南投县德化社 (Tehuashe), 14.xi.2000, Hiroshi Sugaya leg. (in the leaf litter)’ (MHNG); 1 ♀, same data as previous, except ‘4–5.v.(20)01’ (MHNG); 2 ♀♀, ‘Aowanta (1400 m), Nantou, Taiwan, 南投县奥万大, 15.xi.2000, Hiroshi Sugaya leg. (in the leaf litter)’ (MHNG).

Male. Head longer than wide, with weakly indicated anterolateral genal projection, anterior margin of projection oblique; with short ocular canthus; lateral margin of scape straight, antennomeres 9–11 slightly enlarged. Pronotum rounded at anterolateral margins. Ventral margin of profemur with one short and acute, and one tiny spine at base; protibia with one small preapical denticle. Tergite 1 (IV) with median carina extending posteriorly for approximately 1/3 of tergal length, lacking discal carinae. Aedeagus with asymmetric median lobe, apical part of median lobe narrowed and protruding apicad, apex nearly rounded in dorsal view. Female. Similar to male in external morphology, profemur with two ventral spines near base; genital complex as in Fig. 10B.

Male. Body reddish-brown, length 3.68 mm. Head (Fig. 6A) slightly longer than wide, HL 0.74 mm, HW 0.63 mm; anterolateral genal projection weakly developed, anterior margin of projection oblique; antenna 2.03 mm long, scape lacking expansion at lateral margin, antennomeres 2–8 slightly elongate or moniliform, club loosely formed by apical three moderately enlarged antennomeres, antennomere 11 largest, as long as antennomeres 9 and 10 combined; indistinct lateral postantennal pits present; eyes prominent, each composed of approximately 45 large facets, with pair of short ocular canthi (Fig. 6B).

Figure 6. 

Diagnostic characters of Horniella nantouensis sp. nov. A left half of head, in dorsal view B head, in lateral view C protrochanter and profemur D protibia E mesotrochanter and mesofemur F mesotibia G–I aedeagus, in dorsal (G), lateral (H), and ventral (I) view. Scale bars: 0.2 mm (A, B, G–I); 0.3 mm in (C–F).

Pronotum longer than wide, PL 0.77 mm, PW 0.71 mm; widest at apical 1/3; anterolateral margins rounded; disc moderately convex, finely punctate, with distinct median antebasal and lateral antebasal foveae connected by complete transverse antebasal sulcus.

Elytra much wider than long, EL 0.85 mm, EW 1.33 mm; each elytron with two large, setose basal foveae; discal striae extending from outer basal foveae to middle of elytral length.

Legs elongate; protrochanter (Fig. 6C) simple, profemur (Fig. 6C) with one short and acute, and one tiny ventral spine at base; protibia (Fig. 6D) with small preapical spur; mesotrochanter (Fig. 6E) and mesofemur (Fig. 6E) simple, mesotibia (Fig. 6F) with thick apical setae.

Abdomen slightly longer than broad, broadest at lateral margins of tergite 1 (IV), AL 1.32 mm, AW 1.28 mm; tergite 1 (IV) slightly longer than tergites 2 (V), with median carina extending to near basal 1/3 of tergal length, lacking discal carinae, tergite 2 (V) lacking carina, tergites 2–4 (V–VII) each with small basolateral foveae. Sternite 2 (IV) with broad basal sulcus, lacking mediobasal foveae, basolateral foveae developed as large cuticular pockets, with two pairs of antebasal nodules, sternites 3–5 (V–VII) with basolateral foveae, one median and two lateral nodules.

Aedeagus (Fig. 6G–I) 0.57 mm long, with asymmetric median lobe, apical portion of median lobe narrowed and greatly protruding apically, apex nearly rounded in dorsal view; endophallus composed of broad membranous part with single broad elongate sclerite at middle.

Female. General morphology similar to male, each eye composed of approximately 40 facets; profemur each with two distinct ventral spines near base, protibia lacking spur. Measurements (as for male): BL 3.68–3.72 mm, HL 0.74 mm, HW 0.63–0.65 mm, PL 0.72–0.73 mm, PW 0.74–0.75 mm, EL 0.87–0.9 mm, EW 1.33 mm, AL 1.35 mm, AW 1.32–1.33 mm. Genital complex (Fig. 10B) with moderately sclerotized central and membranous lateral parts.

This species is placed as a member of the H. hirtella group. The new species is similar to H. simplaria Yin & Li by the male having similar anterolateral genal projections, and presence of two ventral spines of profemur. They can be otherwise clearly separated by the larger body size (3.68 mm vs 3.23 mm), lack of a mesal hook-like spine of the protibia (present in H. simplaria), and the different shape and structure of the aedeagus of the new species.

China: Taiwan.

The new specific is named after its type locality, Nantou County.

Holotype: East Malaysia: ♂, ‘Borneo: Sabah, Batu Punggul Resort, primary forest, 24.vi.–1.vii.96, Kodada lgt. / vegetation debris and forest floor litter accumulated around large trees near river.’ (MHNG).

Figure 7. 

Dorsal habitus of Horniella species A H. sabahensis sp. nov. B H. taiwanensis sp. nov. Scale bars: 1 mm.

Male. Head longer than wide, anterolateral genal projections weakly developed, anterior margin of projection oblique; scape lacking expansion at lateral margin, antennomeres 9–11 moderately enlarged, forming distinct club. Pronotum rounded at lateral margins. Profemur with two tiny ventral spines near base; metatibia with preapical triangular denticle. Tergite 1 (IV) with median carina extending posteriorly for approximately 3/4 of tergal length, lacking discal carinae, tergite 2 (V) with short median carina. Aedeagus with slightly asymmetric median lobe, apical portion of median lobe narrowed, apex truncate in dorso-ventral view; endophallus lacking sclerite, composed of elongate membranous structure with many small denticles.

Male. Body reddish-brown, length 3.41 mm. Head (Fig. 8A) longer than wide, HL 0.68 mm, HW 0.59 mm; anterolateral genal projection weakly developed, anterior margin of projection oblique; antenna 1.96 mm long, scape lacking expansion at lateral margin, antennomeres 2–8 slightly elongate or moniliform, distinct club formed by apical three enlarged antennomeres, antennomere 11 largest, slightly shorter than antennomeres 9 and 10 combined; indistinct lateral postantennal pits present; eyes prominent, each composed of approximately 40 large facets, usual area of ocular canthus only slightly prominent (Fig. 8B).

Figure 8. 

Diagnostic characters of Horniella sabahensis sp. nov. A left half of head, in dorsal view B head, in lateral view C protrochanter and profemur D protibia E mesotrochanter and mesofemur F mesotibia G metatibia H–J aedeagus, in dorsal (H), lateral (I), and ventral (J) view. Scale bars: 0.2 mm (A, B, H–J); 0.3 mm (C–G).

Pronotum distinctly longer than wide, PL 0.71 mm, PW 0.6 mm; widest at middle; lateral margins rounded; disc moderately convex, finely punctate, with distinct median antebasal and lateral antebasal foveae connected by complete transverse antebasal sulcus.

Elytra much wider than long, EL 0.77 mm, EW 1.2 mm; each elytron with two large, setose basal foveae; discal striae extending from outer basal foveae to apical 2/3 of elytral length.

Legs elongate; protrochanter (Fig. 8C) simple, profemur (Fig. 8C) with two tiny ventral spines at base, protibia (Fig. 8D) simple; mesotrochanter, mesofemur (Fig. 8E) and mesotibia (Fig. 8F) simple; metatibia (Fig. 8G) with distinct apical triangular denticle.

Abdomen slightly longer than broad, broadest at lateral margins of tergite 1 (IV), AL 1.25 mm, AW 1.16 mm; tergite 1 (IV) largest, slightly shorter than tergites 2 and 3 (V and VI) combined, with median carina extending to near basal 3/4 of tergal length, lacking discal carinae, tergite 2 (V) with median carina extending to near basal 1/4 of tergal length, tergites 2–4 (V–VII) each with small basolateral foveae. Sternite 2 (IV) with broad basal sulcus, lacking mediobasal foveae, basolateral foveae developed as large cuticular pockets, with two pairs of antebasal nodules, sternites 3–5 (V–VII) with basolateral foveae, one median and two lateral nodules, sternite 7 (IX) nearly oval, with well-sclerotized apical half and less sclerotized basal half.

Aedeagus (Fig. 8H–J) 0.57 mm long, with slightly asymmetric median lobe, apical part of median lobe narrowed, apex broadly truncate in dorso-ventral view; endophallus lacking strongly sclerotized structures, composed of broad, elongate membrane with numerous small denticles.

Female. Unknown.

Horniella sabahensis sp. nov. is placed as a member of the H. hirtella group. Males of this species share with H. prolixo Yin & Li from Thailand the weakly developed anterolateral genal projections, lack of an expansion at the lateral margin of the scape, and a moderately expanded preapical portion of the metatibia. They can be best separated by the larger body size (3.41 mm vs 2.95–3.02 mm), tergite V with a short median carina (lacking in H. prolixo), as well as the much narrower apex of the aedeagus of the new species.

East Malaysia: Sabah.

The new species is named after its type locality, Sabah, East Malaysia.

Holotype: China: ♂, ‘TAIWAN: Taoyuan City, Northern Cross-island Highway 35.7 k (北横公路35.7 k), Fusing Township, 15-IV-2018, leg. K. X. Zhan’ (NMNS). Paratypes: China: 1 ♂, ‘TAIWAN: Nantou County, Sun Moon Lake (日月潭), Yuchih Township, 13-XII-2016, leg. F. C. Hsu’ (NMNS); 1 ♂, ‘TAIWAN: Taichung City, Dakeng (大坑), Xinshe Dist., 24.1932, 120.7991, 10-IV-2021, leg. C. T. Hsu (under rock)’ (NMNS); 1 ♂, ‘Kuantaoshan, NANTOU, TAIWAN, 南投县关刀山, 16.vii.1999, M. Tanikado leg.’ (MHNG); 1 ♂, ‘Tehuashe (800 m), NANTOU, TAIWAN, 南投县德化社, 2.vii.2000, H. Y. Chu leg. (at light) (MHNG); 1 ♂, ‘Taiwan, Nantou, Meifeng (梅峰), 2100 m, 6.v.01 (sifting of litter), Sugaya lgt.’ (SNUC).

Male. Head longer than wide, with distinct anterolateral genal projections, anterior margin of projection narrowly emarginate, with long ocular canthus; scape roundly expanded at basolateral margin, antennomeres 9–11 slightly enlarged. Pronotum rounded at anterolateral margins. Protrochanter, profemur and mesotrochanter each with ventral spine; protibia and mesotibia with large apical projection. Tergite 1 (IV) with median carina extending posteriorly for approximately 1/4 of tergal length, lacking discal carinae. Aedeagus with asymmetric median lobe, right half of median lobe greatly protruding apicad, apical margin nearly rounded in dorsal view.

Male. Body reddish-brown, length 4.05–4.15 mm. Head (Fig. 9A) slightly longer than wide, HL 0.84–0.87 mm, HW 0.74–0.76 mm; anterolateral genal projection distinct, anterior margin of projection narrowly emarginate; antenna 2.1 mm long, scape roundly expanded at basolateral margin, antennomeres 2–8 slightly elongate or moniliform, club loosely formed by apical three moderately enlarged antennomeres, antennomere 11 largest, slightly shorter than antennomeres 9 and 10 combined; indistinct lateral postantennal pits present; eyes prominent, each composed of approximately 40 large facets, with long ocular canthus (Fig. 9B).

Figure 9. 

Diagnostic characters of Horniella taiwanensis sp. nov. A left half of head, in dorsal view B head, in lateral view C protrochanter and profemur D protibia E mesotrochanter and mesofemur F mesotibia G–I aedeagus, in dorsal (G), lateral (H), and ventral (I) view. Scale bars: 0.2 mm (A, B, G–I); 0.3 mm (C–F).

Pronotum slightly longer than wide, PL 0.78–0.82 mm, PW 0.76–0.77 mm; widest at apical 1/3; anterolateral margins rounded; disc moderately convex, finely punctate, with distinct median antebasal and lateral antebasal foveae connected by complete transverse antebasal sulcus.

Elytra much wider than long, EL 0.94–1.01 mm; EW 1.51 mm; each elytron with two large, setose basal foveae; discal striae extending from outer basal foveae to apical 2/3 of elytral length.

Legs elongate; protrochanter (Fig. 9C) with short, acute ventral spine, profemur (Fig. 9C) with distinctly long ventral spine near base; protibia (Fig. 9D) with large apical projection; mesotrochanter (Fig. 9E) with sharp ventral spine, mesofemur (Fig. 9E) simple, mesotibia (Fig. 9F) with moderately large projection.

Abdomen approximately as long as broad, broadest at lateral margins of tergite 1 (IV), AL 1.45–1.49 mm, AW 1.47–1.49 mm; tergite 1 (IV) slightly longer than tergites 2 (V), with short median carina extending to near basal 1/4 of tergal length, lacking discal carinae, tergite 2 (V) lacking carina, tergites 2–4 (V–VII) each with small basolateral foveae. Sternite 2 (IV) with broad basal sulcus, lacking mediobasal foveae, basolateral foveae developed as large cuticular pockets, with two pairs of antebasal nodules, sternites 3–5 (V–VII) with basolateral foveae, one median and two lateral nodules, sternite 7 (IX) with well-sclerotized apical half and less sclerotized basal half.

Aedeagus (Fig. 9G–I) 1.01 mm long, with strongly asymmetric median lobe, right half of median lobe greatly protruding apicad, apex broadened, with round apical margin dorso-ventral view; endophallus composed of one elongate, and two much shorter sclerites.

Female. Unknown.

This species is placed as a member of the H. centralis group and is most similar to H. sichuanica Yin & Li in the shapes of the anterolateral genal projections and spination of the legs. They can be clearly separated by the larger body size (4.05–4.15 mm vs 3.58–3.77 mm), the more distinct apical projections of protibia and mesotibia, and the dilated apex of the aedeagal median lobe of the new species.

China: Taiwan.

The new specific is named after Taiwan.

Figure 10. 

Female genitalia of Horniella species, in dorsal view A H. bifurca sp. nov. B H. nantouensis sp. nov. Scale bars: 0.2 mm.