taxonID	type	description	language	source
03B587B33705FF96FF6B06A8FDECF830.taxon	description	urn: lsid: zoobank. org: act: 9 E 25 A 362 - E 1 A 1 - 41 EE- 8 E 0 F- 2117296 A 78 CB Figs. 1 A – B; 2 A – C; 3 A – L; 4 A – H; 5 A – C; 6 A – D; 7; 8; 9	en	Qi, Zhi-Hao, Bian, Cheng-Zhi, Xin, Fei-Yi, Dang, Van Ngoc, Song, Hai-Tian, Liang, Guang-Hong (2025): A new species of the genus Prosopocoilus Hope, 1845 from southern Vietnam (Coleoptera: Lucanidae: Lucaninae). Zootaxa 5737 (4): 551-564, DOI: 10.11646/zootaxa.5737.4.5, URL: https://doi.org/10.11646/zootaxa.5737.4.5
03B587B33705FF96FF6B06A8FDECF830.taxon	materials_examined	Type material. Holotype: ♂ (NACRC: IOZ (E) 224809), VIETNAM, Lam Dong Province, Bao Loc City, alt. 700 – 800 m, VIII. 2023, Van Ngoc Dang leg. Paratypes: 1 ♂, 2 ♀♀ (1 ♂ CCZB, 2 ♀♀ CZHQ), same data as for holotype; 4 ♀♀ (CCZB), same data as for holotype except VIII. 2017; 1 ♂, 1 ♀ (CCZB), same data as for holotype except VI. 2016.	en	Qi, Zhi-Hao, Bian, Cheng-Zhi, Xin, Fei-Yi, Dang, Van Ngoc, Song, Hai-Tian, Liang, Guang-Hong (2025): A new species of the genus Prosopocoilus Hope, 1845 from southern Vietnam (Coleoptera: Lucanidae: Lucaninae). Zootaxa 5737 (4): 551-564, DOI: 10.11646/zootaxa.5737.4.5, URL: https://doi.org/10.11646/zootaxa.5737.4.5
03B587B33705FF96FF6B06A8FDECF830.taxon	description	Description of the holotype. Male, body length 28.7 mm. Length of particular body parts: head (5.1 mm), mandible (6.5 mm), pronotum (4.9 mm), elytra (13.3 mm); width of: head (8.1 mm), pronotum (8.8 mm), elytra (9.1 mm). Habitus (Figs. 1 A – B). Body dark chestnut with a certain luster, generally glabrous. The dorsal surface of head and pronotum with a fine, matte texture, while elytral surface relatively smooth. Head transverse, about 1.6 times wider than long, widest at eyes. Anterior margin widely and distinctly concave. Canthus dividing about 1 / 4 of the eye; preocular margin (Fig. 3 A) protrudes outward, forming a rounded angle. Clypeolabrum (Fig. 3 B) small and transverse, 2.6 times wider than long, distinctly protruded forward at the middle with apex rounded; lateral angles of clypeolabrum weakly acute. Mandible about 1.3 times as long as head, generally straight, and slightly curved behind the apex; a relatively large basal tooth present at basal 1 / 4, and rounded at the apex; 7 – 9 continuous small, rectangular or rounded inner teeth located anterior to the basal tooth; the tip of the mandible sharp, with a small, rounded tooth behind the apex; behind this small tooth, there is a distinct gap that separates it from the other consecutive teeth. Postocular margin bulged into a broad and moderate process. Mentum (Fig. 3 C) transverse, about 3.1 times wider than long, anterior margin slightly emarginated at middle, lateral angles absent. Left antennal club with three antennomeres, antennomere 7 sharply extended inwards, antennomeres 8 – 9 lamellate, terminal antennomere semicircular; right antennal club teratological, the expanded part of antennomeres 8 – 9 abnormally fused together. Pronotum transverse, 1.8 times wider than long, widest at the middle. Anterior margin bisinuate, anterior angles rounded; lateral angles slightly produced and obtuse; posterior margin slightly bisinuate, posterior angles obtuse. Scutellum subtriangular, punctuated, 1.3 times wider than long. Legs. Protibia (Fig. 3 D) distinctly expanded apically, and outer margin finely serrate, almost invisible to the naked eye (excluding apical fork); apical part of inner margin with dense yellow setae; base of apical fork strongly extend, with sharp branches at tip. Mesotibia (Fig. 3 E) with one tiny lateral spine, and one obvious terminal spine. Metatibia (Fig. 3 F) without lateral spine, and with one obvious terminal spine. Ventral surface of all tarsi bears distinct yellow setae. Elytra elongate, about 1.5 times longer than wide, widest at the middle; anterior margin of elytra slightly narrower than pronotum; anterior part with dense punctures, and the area beyond that finely punctate. Abdomen and aedeagus. Abdominal tergite 8 (Fig. 4 A) with a longitudinal membranous stripe in the middle, extending from the base to near the apex; abdominal ventrite 8 (Fig. 4 B) with a pair of circular membranous patches at middle of basal part, and apex membranous. Abdominal segment 9 (Fig. 4 C – D) slender, the ventral plate (Fig. 4 D) narrowest near basal 1 / 3, without membranous area. Aedeagus (Figs. 5 A – C; 6 A) about 2.8 times longer than wide in ventral view. Basal piece distinctly constricted in basal part, about 1.5 times as long as parameres, with a pair of narrow and sclerotized dorsal plates (Fig. 5 B). Paramere without basal process, weakly upturned and apically sharp in lateral view (Fig. 5 C). Penis subtriangular apically, distinctly shorter and wider than paramere, widest at base. Flagellum (Figs. 6 A – B) slender and trifurcate, about 0.8 times as long as aedeagus; median branch very slender with apex simple; lateral branches relatively wide, apices shown in Fig. 6 B. Male paratypes. Body length 31.6 – 34.1 mm (n = 2). Variation. In the medium and large sized male (Fig. 2 A – C), mandible about 1.5 – 1.6 times as long as head; mandible with 8 – 11 continuous inner teeth; the gap behind apex deeper; basal tooth and the tooth behind apex larger. The protuberance on clypeolabrum larger and more distinct. Female paratypes. Body length 18.8 – 21.8 mm (n = 5). Habitus (Fig. 7 A – D). Color dark chestnut to black with a certain luster, generally glabrous and punctate. Head (Fig. 8 A) transverse, widest at canthi. Anterior margin widely and slightly concave. Canthus (Fig. 8 B) broad, dividing about 2 / 3 of the eye; preocular margin without protrusion. Clypeolabrum (Fig. 8 C) small and transverse, about 2.9 times wider than long; lateral angles of clypeolabrum almost absent. Mandible about 0.7 times as long as head, slightly curved with apex sharp; a single inner tooth located at middle of right mandible, and a broad, irregular inner tooth located at middle of the left one. Postocular part obsolete. Mentum (Fig. 8 D) transverse, about 1.6 times wider than long, lateral angles absent; surface of mentum bears dense, irregular, and large elliptical punctures. Antennal club with three antennomeres, antennomere 6 slightly extended inwards, antennomere 7 sharply extended inwards, antennomeres 8 – 9 lamellate, terminal antennomere semicircular. Pronotum transverse and rounded, about 1.6 times wider than long, widest at the middle. Anterior margin slightly bisinuate, anterior angles rounded; lateral angles absent; posterior margin nearly straight, posterior angles obtuse. Scutellum subtriangular, punctuated, about 1.3 times wider than long. Legs. Protibia (Fig. 8 E) with 5 – 9 continuous, obtuse teeth (excluding apical fork) gradually larger from base to apex along outer margin; apical part of inner margin bears long yellow setae, with lengths equal to the spur; base of apical fork moderately extend, with sharp branches at tip. Mesotibia (Fig. 8 F) with one large lateral spine, and three terminal spines. Metatibia (Fig. 8 G) with one large lateral spine, and three terminal projections, among which the dorsal one largest and distinctly extended, with a rounded apex. Ventral surface of all tarsi bears distinct yellow setae. Elytra elongate, about 1.5 times longer than wide, widest at the middle; anterior margin of elytra distinctly narrower than pronotum. Each elytron with regular, moderately dense rows of larger punctures, while the marginal area with dense and irregular punctures. Abdomen and female genitalia. Abdominal tergite 8 (Fig. 9 A, D) with a broad longitudinal membranous stripe in the middle, extending from the base to near the apex, apex truncate; abdominal ventrite 8 (Fig. 9 B, E) with a broad longitudinal membranous stripe in the middle, extending from the base to the apex, apex membranous. Hemisternite (Fig. 9 C, F) slender and relatively straight, with basal part slightly curved inward, apex rounded. Spermatheca (Fig. 9 H, J) long oval, not sclerotized. Spermathecal duct (Fig. 9 G, I) about 1.5 times as long as hemisternite. Spermathecal gland (Fig. 9 G, I) irregular long oval, significantly smaller than spermatheca, insertion point at base of spermatheca duct.	en	Qi, Zhi-Hao, Bian, Cheng-Zhi, Xin, Fei-Yi, Dang, Van Ngoc, Song, Hai-Tian, Liang, Guang-Hong (2025): A new species of the genus Prosopocoilus Hope, 1845 from southern Vietnam (Coleoptera: Lucanidae: Lucaninae). Zootaxa 5737 (4): 551-564, DOI: 10.11646/zootaxa.5737.4.5, URL: https://doi.org/10.11646/zootaxa.5737.4.5
03B587B33705FF96FF6B06A8FDECF830.taxon	diagnosis	Differential diagnosis. This new species is most closely related to Prosopocoilus mysticus mysticus Parry, 1870. However, it can be clearly distinguished from the latter in males based on the following morphological characters: 1) mandibles usually 1.3 – 1.6 times as long as head, with distinct continuous small inner teeth, basal tooth more developed and directed laterally, rather than mandibles usually 1.6 – 2.3 times as long as head, in individuals with continuous small teeth, most of continuous teeth indistinct, basal tooth relatively small and directed posterolaterally; 2) preocular margin protrudes outward forming a rounded angle (Fig. 3 A, G), instead of preocular margin without a projection (Fig. 3 M, S); 3) clypeolabrum distinctly protruded forward at middle (Fig. 3 B, H), instead of clypeolabrum bilobate, distinctly notched at middle (Fig. 3 N, T) (excluding the large individual shown in Fig. 2 D); 4) surface of mentum without any large punctures (Fig. 3 C, I), rather than with some large punctures (Fig. 3 O, U); 5) inner margin of protibia curved inward (Fig. 3 D, J), rather than curved outward (Fig. 3 P, V); 6) longitudinal membranous stripe of abdominal tergite 8 widest at base (Fig. 4 A, E), instead of widest near the middle (Fig. 4 I, M); 7) abdominal ventrite 8 with a pair of circular membranous patches at base (Fig. 4 B, F), instead of without membranous patches (Fig. 4 J, N); 8) penis significantly larger (Fig. 5 A), and apices of parameres relatively wide (Fig. 5 B), rather than penis tiny (Fig. 5 D), and apices of parameres relatively narrow (Fig. 5 E). In addition, the new species is also similar to Prosopocoilus dubius (de Lisle, 1968) from Palawan, but exhibits distinct differences in the morphological details of the male mandibles and geographic distribution.	en	Qi, Zhi-Hao, Bian, Cheng-Zhi, Xin, Fei-Yi, Dang, Van Ngoc, Song, Hai-Tian, Liang, Guang-Hong (2025): A new species of the genus Prosopocoilus Hope, 1845 from southern Vietnam (Coleoptera: Lucanidae: Lucaninae). Zootaxa 5737 (4): 551-564, DOI: 10.11646/zootaxa.5737.4.5, URL: https://doi.org/10.11646/zootaxa.5737.4.5
03B587B33705FF96FF6B06A8FDECF830.taxon	etymology	Etymology. The new species is named after Ms. Xin-Yi Wang (Beijing, China), the girlfriend of the second author.	en	Qi, Zhi-Hao, Bian, Cheng-Zhi, Xin, Fei-Yi, Dang, Van Ngoc, Song, Hai-Tian, Liang, Guang-Hong (2025): A new species of the genus Prosopocoilus Hope, 1845 from southern Vietnam (Coleoptera: Lucanidae: Lucaninae). Zootaxa 5737 (4): 551-564, DOI: 10.11646/zootaxa.5737.4.5, URL: https://doi.org/10.11646/zootaxa.5737.4.5
03B587B33705FF96FF6B06A8FDECF830.taxon	distribution	Distribution. Vietnam (Lam Dong).	en	Qi, Zhi-Hao, Bian, Cheng-Zhi, Xin, Fei-Yi, Dang, Van Ngoc, Song, Hai-Tian, Liang, Guang-Hong (2025): A new species of the genus Prosopocoilus Hope, 1845 from southern Vietnam (Coleoptera: Lucanidae: Lucaninae). Zootaxa 5737 (4): 551-564, DOI: 10.11646/zootaxa.5737.4.5, URL: https://doi.org/10.11646/zootaxa.5737.4.5
03B587B3370FFF92FF6B027AFD98FF70.taxon	description	Figs. 1 C – D; 2 D – G; 3 M – X; 4 I – P; 5 D – F; 6 E – H	en	Qi, Zhi-Hao, Bian, Cheng-Zhi, Xin, Fei-Yi, Dang, Van Ngoc, Song, Hai-Tian, Liang, Guang-Hong (2025): A new species of the genus Prosopocoilus Hope, 1845 from southern Vietnam (Coleoptera: Lucanidae: Lucaninae). Zootaxa 5737 (4): 551-564, DOI: 10.11646/zootaxa.5737.4.5, URL: https://doi.org/10.11646/zootaxa.5737.4.5
03B587B3370FFF92FF6B027AFD98FF70.taxon	materials_examined	Material examined. MALAYSIA: 5 ♂♂ (CCZB), Perak State, Batang Padang District, Tapah Hill, alt. 700 m, V. 2025, local collector leg.	en	Qi, Zhi-Hao, Bian, Cheng-Zhi, Xin, Fei-Yi, Dang, Van Ngoc, Song, Hai-Tian, Liang, Guang-Hong (2025): A new species of the genus Prosopocoilus Hope, 1845 from southern Vietnam (Coleoptera: Lucanidae: Lucaninae). Zootaxa 5737 (4): 551-564, DOI: 10.11646/zootaxa.5737.4.5, URL: https://doi.org/10.11646/zootaxa.5737.4.5
03B587B3370FFF92FF6B027AFD98FF70.taxon	distribution	Distribution. Malay Peninsula.	en	Qi, Zhi-Hao, Bian, Cheng-Zhi, Xin, Fei-Yi, Dang, Van Ngoc, Song, Hai-Tian, Liang, Guang-Hong (2025): A new species of the genus Prosopocoilus Hope, 1845 from southern Vietnam (Coleoptera: Lucanidae: Lucaninae). Zootaxa 5737 (4): 551-564, DOI: 10.11646/zootaxa.5737.4.5, URL: https://doi.org/10.11646/zootaxa.5737.4.5
03B587B33708FF92FF6B0414FDFEFBF4.taxon	discussion	There are currently 19 clearly recorded taxa of the genus Prosopocoilus in Vietnam (Fujita 2010; Huang & Chen 2013; Tsuchiya 2021; Yi 2023; Schenk 2023; the present study):	en	Qi, Zhi-Hao, Bian, Cheng-Zhi, Xin, Fei-Yi, Dang, Van Ngoc, Song, Hai-Tian, Liang, Guang-Hong (2025): A new species of the genus Prosopocoilus Hope, 1845 from southern Vietnam (Coleoptera: Lucanidae: Lucaninae). Zootaxa 5737 (4): 551-564, DOI: 10.11646/zootaxa.5737.4.5, URL: https://doi.org/10.11646/zootaxa.5737.4.5
