Alexeter hsiaoae Chen, Huang & Shiao, 2025

Alexeter hsiaoae Chen, Huang & Shiao sp. nov.

Figs 5 A – H View Figure 5 , 10 C View Figure 10 , 11 G – I View Figure 11 ; Suppl. material 3 Chinese vernacular name: 郁薇亞力姬蜂

Material examined.

Holotype. Taiwan • 1 ♀; Taichung City, Heping District, Mt. Nanhu U-shape valley , 24.369516 ° N, 121.443366 ° E (DD); alt. 3450 m; 16. Jul. 2021; Light Trap; C. - L. Huang & Y. - W. Hsiao leg.; GenBank: PV 223403 ( COI); NMNS ENT 8951-1 (Mesolei 01) GoogleMaps . Paratypes. Taiwan • 1 ♀ 4 ♂♂; same as holotype; GenBank: PV 223405 , PV 223406 ( COI); NMNS ENT 8951-2 – 3 (Mesolei 02–03), TARI (Mesolei 12–13), KPMNH (Mesolei 14) GoogleMaps • 1 ♂; Taichung City, Heping District, Eastern Peak of Mt. Syueshan – 369 Cabin ; alt. 3000–3200 m; 26–27. Aug. 2021; Sweeping; C. - T. Hsu leg.; GenBank: PV 223404 ( COI); NMNS ENT 8951-4 (Mesolei 06) • 1 ♀ 2 ♂♂; Hualien County, Wanrung Township, Mt. Antungchunshan, No. C 2 ; 4. Aug. 1993; S. S. Lu leg.; TFRI 00073669 –00073671 .

Diagnosis.

This species can be distinguished from congeners by the combination of the following characters: fore wing length usually shorter than 10.0 mm ( 7.8–10.4 mm); ocelli large ( OD = 0.18–0.25 mm; OOL / OD = 0.6–0.9); POL / OOL = 0.8–1.1; female with flagellum segments 46; fore wing areolet trapezoid with stalk, receiving 2 m-cu at distal corner (Fig. 10 C View Figure 10 ); fore wing 1 cu-a almost vertical, opposite or slightly distad to M & RS (Fig. 10 C View Figure 10 ); lateromedian longitudinal carinae of propodeum present posteriorly with the area petiolaris opened (Fig. 5 E View Figure 5 ); T 1 3.1–4.3 × its posterior width; head generally yellowish-white with frons and vertex brown to blackish-brown (Fig. 5 A, B View Figure 5 ); mesosoma, legs, and metasoma generally yellowish-brown, with mesoscutum having three distinct blackish-brown longitudinal stripes on the lobes (Fig. 5 A, D View Figure 5 ).

This new species is most similar to A. clavator (Müller, 1776) , A. monticola sp. nov., and A. mediolobus sp. nov. which share generally yellowish color in head, mesosoma, and metasoma, but can be distinguished from them by the POL / OOL ratio (0.8–1.1 vs 1.3 in Chinese A. clavator ( Li and Sun 2022) and 1.1–1.5 in A. mediolobus sp. nov.), female OOL / OD ratio (0.7–0.9 vs 0.5–0.7 in A. mediolobus sp. nov. and A. monticola sp. nov.), length-to-posterior-width ratio of T 1 (3.1–4.3 vs 2.5–3.1 in A. mediolobus sp. nov.), female flagellomere counts (46 vs 40–43 in A. mediolobus sp. nov.), color patterns of mesoscutum (three stripes on each lobe vs absent in A. clavator and one on the median lobe in A. mediolobus sp. nov.), gena (yellowish-white vs yellowish-brown to brown in other species), vertex (brown vs yellowish-brown or orange in A. monticola sp. nov.), and fore and mid coxae (yellowish-white vs yellowish-brown in A. monticola sp. nov.).

For other yellowish- or reddish-brown species A. nebulator (Thunberg, 1822) , A. gracilentus (Holmgren, 1857) , and A. luteifrons (Cresson, 1868) , this new species can be easily distinguished from them by having a yellowish-white head (black in these species) and three blackish-brown stripes on the lobes of mesoscutum (stripes absent in these species). A comparative table of the measurements, ratios, and colors of this new species and other yellowish- or reddish-brown Alexeter species are provided in Suppl. material 3.

Additionally, this new species may also be confused with two species of the genus Barytarbes , B. fulvus Sheng & Schönitzer, 2008 and B. nigrimaculatus Sheng & Sun, 2017 , which share a generally yellowish-brown body color and the absence of lateromedian longitudinal carinae on the anterior and median portions of propodeum. However, this new species can be distinguished from both Barytarbes species by having mandibular teeth equal in length (Fig. 5 C View Figure 5 ) (lower tooth longer in both species), T 1 with distinct glymma (Fig. 5 G View Figure 5 ) (glymma absent in B. fulvus and indistinct in B. nigrimaculatus ), T 1 3.1–4.3 × its posterior width (~ 1.9 × in B. nigrimaculatus , 4.0 × in B. fulvus ), mesoscutum with three distinct blackish-brown longitudinal stripes (Fig. 5 D View Figure 5 ) (without stripes on mesoscutum in B. fulvus ), and metasomal tergites without black markings (Fig. 5 A View Figure 5 ) (with black markings in B. nigrimaculatus ).

Description.

The measurements were based on Taiwanese specimens ( 3 females and 7 males).

Female. Head (Fig. 5 A – C View Figure 5 ): matt and minutely coriaceous, HW / HL = 1.6–1.9 (1.9, 1.8 ± 0.15); ocelli large, with OD = 0.20–0.25 (0.21, 0.22 ± 0.03) mm, POL / OD = 0.5–0.9 (0.9, 0.7 ± 0.19), OOL / OD = 0.7–0.9 (0.8, 0.8 ± 0.11), POL / OOL = 0.8–1.1 (1.1, 0.9 ± 0.18); face matt and minutely coriaceous, FW / FH = 1.37–1.44 (1.4, 1.41 ± 0.05); clypeus flat, polished and smooth with sparce punctures, truncate on ventral margin, CLW / CLH = 2.9–3.3 (3.3, 3.1 ± 0.28); MSL / BMW = 0.3–0.7 (0.3, 0.5 ± 0.21); mandible smooth with sparce punctures, teeth equal in length; flagellum with 46 (46) segments; average ratio of basal five flagellomeres length 2.5: 1.3: 1.1: 1.1: 1.0.

Mesosoma (Fig. 5 A, D, E View Figure 5 ): matt and minutely coriaceous; pronotum with epomia weak; mesoscutum with MSSL / MSSW = 1.1–1.2 (1.1, 1.1 ± 0.07), notauli short and distinct near anterior margin; scutellum with SCL / SCW = 1.2–1.3 (1.2, 1.3 ± 0.01), lateral carina present anteriorly; epicnemial carina strong, ~ 0.6 × height of mesopleuron; metapleuron with pleural carina and submetapleural carina complete; juxtacoxal carina absent; propodeum with spiracle circular, maximum axis 1.0–1.1 (1.0, 1.04 ± 0.06) × as minimum axis; anterior transverse carinae absent; posterior transverse carina absent but vestigial medially; lateromedian longitudinal carinae absent on anterior and median portions, present on posterior ~ 0.3–0.4 with area petiolaris opened anteriorly; lateral longitudinal carinae vestigial posteriorly; average ratio of hind tarsomere length 4.1: 2.2: 1.7: 1.0: 1.2.

Wings (Fig. 10 C View Figure 10 ): fore wing length 8.7–10.4 (8.94, 9.4 ± 0.91) mm; areolet open and trapezoid with stalk 0.4–0.5 (0.4, 0.4 ± 0.05) as long as 2 rs-m, receiving 2 m-cu at distal corner; RMI = 0.5–0.8 (0.8, 0.7 ± 0.12); 1 cu-a almost vertical, opposite or slightly distad to M & RS, with BNI = 0.1–0.2 (0.2, 0.2 ± 0.02). Hind wing length 6.8–7.9 (6.77, 7.2 ± 0.62) mm; NI = 1.7–3 (1.7, 2.2 ± 0.71); distal hamuli 5–6 ( 6 in left and 5 in right wing).

Metasoma (Fig. 5 F – H View Figure 5 ): matt and minutely coriaceous; T 1 3.1–3.8 (3.1, 3.3 ± 0.43) × as long as posterior width, 6.2–8.2 (6.2, 7.0 ± 1.07) × as long as anterior width, 1.3–1.5 (1.3, 1.4 ± 0.09) × as long as length of T 2; T 1 with latero-median carina absent, dorso-lateral carina present basally, ventro-lateral carina complete, spiracle at around middle of T 1, glymma distinct; T 2 1.1–1.4 (1.2, 1.2 ± 0.13) × as long as posterior width, 1.9–2.3 (2.1, 2.1 ± 0.2) × as long as anterior width, gastrocoeli indistinct, thyridia deep and semi-circular; ovipositor sheath 3.3–5.6 (3.3, 4.6 ± 1.21) × as long as its maximum width in lateral view, shorter than apical depth of metasoma.

Color (Figs 5 View Figure 5 , 10 C View Figure 10 ): head yellowish-white, except antenna yellowish-brown; vertex brown; frons and areas between lateral ocelli and eyes blackish-brown. Mesosoma, legs, and metasoma generally yellowish-brown, except pronotum, ventral and anterior area of mesopleuron, mesoscutum, scutellum, fore and mid coxae, and trochanters yellowish-white, three longitudinal stripes on lobes of mesoscutum and T 1 dark brown to blackish-brown. Wings hyaline, veins blackish-brown, and pterostigma pale yellowish-brown.

Male. General structure and color similar to female. Male genitalia with gonostyle tapered and rounded apically, S 9 weakly concave on posterior margin, completely sclerotized (Fig. 11 G – I View Figure 11 ).

HW / HL = 1.7–1.9 (1.8 ± 0.08); OD = 0.18–0.23 (0.21 ± 0.02) mm, POL / OD = 0.6–0.9 (0.7 ± 0.12), OOL / OD = 0.6–0.8 (0.7 ± 0.09), POL / OOL = 0.9–1.1 (1 ± 0.08); FW / FH = 1.3–1.7 (1.4 ± 0.13), CLW / CLH = 3.0–3.6 (3.3 ± 0.29), MSL / BMW = 0.3–0.4 (0.3 ± 0.05); flagellum with 42–47 segments; average ratio of basal five flagellomeres length 2.3: 1.3: 1.1: 1.1: 1.0; MSSL / MSSW = 1.1–1.3 (1.2 ± 0.09); SCL / SCW = 1.0–1.4 (1.2 ± 0.12); maximum axis of propodeal spiracles 1.0–1.2 (1.1 ± 0.09) × as minimum axis; average ratio of hind tarsomere length 3.8: 2.0: 1.6: 1.0: 1.1; fore wing length 7.8–9.7 (8.9 ± 0.63) mm; areolet with stalk 0.3–0.5 (0.4 ± 0.06) × as long as 2 rs-m; RMI = 0.6–0.8 (0.7 ± 0.09); BNI = 0.1–0.2 (0.2 ± 0.03); hind wing length 5.7–7.0 (6.4 ± 0.47) mm; NI = 1.8–3.0 (2.5 ± 0.43); distal hamuli 4–7; T 1 3.5–4.3 (3.9 ± 0.29) × as long as posterior width, 7.0–10.4 (8.2 ± 1.18) × as long as anterior width, 1.3–1.5 (1.4 ± 0.06) × as long as length of T 2; T 2 1.2–1.6 (1.4 ± 0.16) × as long as posterior width, 1.6–2.6 (2.2 ± 0.32) × as long as anterior width.

Bionomics.

This species has been collected from high-elevation mountains in Taiwan above 3000 m by light trap or sweeping. Hosts are unknown.

Distribution.

Taiwan ( Hualien andTaichung).

Etymology.

The eponym of the specific name hsiaoae is the Chinese family name ‘ Hsiao’ combined with the feminine suffix ‘ - ae ’. It is dedicated to memory the deceased collector of the type series, Ms. Yu-Wei Hsiao. The name is a noun in the genitive case.

Remarks.

Large variation in the MSL / BMW ratio is observed in this species, ranges from 0.3 to 0.7. Despite variation in structures, the color patterns of the gena, coxae, and mesoscutum are consistent and can serve as crucial diagnostic characters. Alexeter hsiaoae sp. nov. is nested within Alexeter Clade I in the current COI - based phylogeny (Fig. 2 View Figure 2 ).