Research Article |
Corresponding author: Ngat Thi Tran ( tranthingat1012@gmail.com ) Corresponding author: Michael S. Engel ( msengel@ku.edu ) Academic editor: Thorleif Dörfel
© 2023 Ngat Thi Tran, Michael S. Engel, Cuong Quang Nguyen, Duong Dinh Tran, Lien Thi Phuong Nguyen.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Tran NT, Engel MS, Nguyen CQ, Tran DD, Nguyen LTP (2023) The bee genus Anthidiellum in Vietnam: descriptions of five new species and the first male of Anthidiellum coronum (Hymenoptera, Megachilidae). ZooKeys 1144: 171-196. https://doi.org/10.3897/zookeys.1144.98644
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The Vietnamese fauna of bees in the Anthidiellum Cockerell (Megachilinae, Anthidiini) is reviewed. Seven species are recognized, representing two subgenera. Five new species are described and figured as: Anthidiellum (Clypanthidium) nahang Tran, Engel & Nguyen, sp. nov., A. (Pycnanthidium) ayun Tran, Engel & Nguyen, sp. nov., A. (P.) chumomray Tran, Engel & Nguyen, sp. nov., A. (P.) flavaxilla Tran, Engel & Nguyen, sp. nov., and A. (P.) cornu Tran, Engel & Nguyen, sp. nov. from the northern and central highlands of Vietnam. Two previously described species are newly recorded for the fauna: A. (P.) carinatum (Wu) and A. (P.) coronum (Wu), with the male of the latter species described and illustrated for the first time. An identification key is provided for all species of Anthidiellum occurring in Vietnam.
Apoidea, Anthidiini, Megachilinae, morphology, taxonomy
The genus Anthidiellum Cockerell (Anthidiini) consists of typically small, robust, megachiliform to somewhat bombiform bees. It can be separated from other genera by the following characteristics: body small, robust, metasoma oval-rounded, with strongly developed omaular carinae/lamellae, and an often-lamellate pronotal lobe (
Currently, the genus Anthidiellum comprises nearly 65 described species in seven subgenera, most of which are found in the Old World (
In Vietnam, only two prior records of the genus were known from northern provinces (
Summary of species currently in the genus Anthidiellum Cockerell from Vietnam.
Species | Sexes known | Distribution |
---|---|---|
Anthidiellum (Clypanthidium) nahang Tran, Engel & Nguyen, sp. nov. | ♀ | Tuyen Quang |
Anthidiellum (Pycnanthidium) ayun Tran, Engel & Nguyen, sp. nov. | ♀ | Gia Lai |
Anthidiellum (Pycnanthidium) carinatum (Wu, 1962) * | ♀♂ | Son La, Vinh Phuc, Kon Tum, Gia Lai, Dak Lak |
Anthidiellum (Pycnanthidium) chumomray Tran, Engel & Nguyen, sp. nov. | ♀ | Kon Tum |
Anthidiellum (Pycnanthidium) flavaxilla Tran, Engel & Nguyen, sp. nov. | ♀ | Gia Lai |
Anthidiellum (Pycnanthidium) cornu Tran, Engel & Nguyen, sp. nov. | ♂ | Kon Tum |
Anthidiellum (Pycnanthidium) coronum (Wu, 2004)** | ♀♂ | Gia Lai |
Specimens examined in the present study are deposited in the collection of Hymenoptera of the Institute of Ecology and Biological Resources (IEBR), Hanoi, Vietnam and Division of Invertebrate Zoology, American Museum of Natural History, New York, USA (
Subgenus Clypanthidium Pasteels, 1968
Holotype. Vietnam: ♀, Tuyen Quang, Na Hang, v.2018 [May 2018], malaise trap, Long Dang Khuat leg. [IEBR].
The female of this species is most similar to that of A. (Clypanthidium) popovii (Wu, 1962), as both have the mandible much broader apically than basally; metatibia and metabasitarsus both without a longitudinal carina on the prolateral surface; metabasitarsus slender, width much less than greatest width of metatibia; forewing with veins bicolorous; and metasomal T1–T3 black. The new species can be distinguished from the female of the latter species by the following: mandible with interspace between the first two teeth broad, about 2× the interspace between the second and third tooth (mandible with interspace of the first two teeth narrow, subequal to that between the second and third tooth in A. popovii), mesoscutum with postero-lateral corner forming an obtuse angle (mesoscutum with postero-lateral corner forming a nearly right angle in A. popovii), clypeus with small yellow markings laterally (clypeus without yellow markings laterally in A. popovii), forewing rather transparent basally and dark brown distally (forewing dark basally and yellow distally in A. popovii), metasomal T4 black and T5–T6 yellow (metasomal T4–T5 yellow, T6 black in A. popovii).
♀: body length (holotype) 9.5 mm, forewing length (holotype) 9 mm.
Structure. Head broader than long, approximately 1.2× as broad as long (Fig.
Anthidiellum (Clypanthidium) nahang Tran, Engel & Nguyen, sp. nov., holotype, female A lateral habitus B dorsal habitus C facial view D mesosoma in dorsal view E head and mesosoma in profile F apical metasomal terga G metapretarsus, red arrow indicating arolium. Scale bars: 1 mm (A–F); 0.5 mm (G).
Sculpturing and texture. Mandible with small, dense, nearly contiguous punctures. Clypeus with round, dense, nearly contiguous punctures of unequal sizes, puncture sizes larger laterally than those on disc (Fig.
Color. Body black except as follows: clypeus with yellow markings laterally, paraocular area with yellow markings baso-laterally; mandible with yellowish-brown apex (Fig.
Pubescence. Paraocular area with short, sparse, white setae. Clypeus with short, sparse, white setae laterally and some short yellowish setae apically. Antennal scape with short, yellowish setae; face above antennal torulus with diffuse tufts of white setae (Fig.
♂: Latet.
The specific epithet is a toponym for the type locality, the Na Hang district in Tuyen Quang Province. The name is treated as a noun in apposition.
Based on the presence or absence of a longitudinal carina on the prolateral surface of the metatibia and metabasitarsus and the normal or enlarged metabasitarsus of the female, Pycnanthidium can be divided into two distinctive groups: the first group with nine species includes A. carinatum (Wu), A. biroi (Friese), A. forstenii (Ritsema), A. nigriceps (Friese), A. riparium (Cockerell), A. smithii (Ritsema), A. ayun Tran, Engel & Nguyen, sp. nov., A. chumomray Tran, Engel & Nguyen, sp. nov., and A. flavaxilla Tran, Engel & Nguyen, sp. nov., while the second group, with a similar number of species, includes A. butarsis Griswold, A. coronum (Wu), A. krombeini Griswold, A. latipes (Bingham), A. melanaspis Cockerell, A. ramakrishnae (Cockerell), A. rasorium (Smith), A. turneri (Friese), and A. cornu Tran, Engel & Nguyen, sp. nov.
Holotype. Vietnam: ♀, Gia Lai, Mang Yang, Ayun, Kon Ka Kinh NP, 14°13'18"N, 108°19'02"E, alt. 907 m, 26.iii.2022 [26 March 2022], Lien Thi Phuong Nguyen, Ngat Thi Tran, Cuong Quang Nguyen leg. [IEBR].
Paratypes. Vietnam: 51♀♀, same data as holotype [41♀♀ in IEBR; 10♀♀ in
This female of this species is most similar to A. (P.) chumomray (vide infra), sharing with it the following characters: metatibia and metabasitarsus with a longitudinal carina on prolateral surfaces, and metasomal T2, supraclypeal area, pronotal lobe, and axillae black. It can be separated from that species easily by the following characters: mandible tridentate, teeth gradually longer and teeth sharp apically; clypeus approximately 1.4× as broad as long and with trapezoidal yellow marking medially; mesoscutellum convex and bigibbous; paraocular area black.
♀: body length 7.0–7.5 mm (holotype = 7.5 mm). Forewing length 6.5–7.0 mm (holotype = 7.0 mm).
Structure. Head broader than long, approximately 1.2× as broad as long (Fig.
Anthidiellum (Pycnanthidium) ayun Tran, Engel & Nguyen, sp. nov., holotype, female A dorsolateral oblique habitus B dorsal habitus C facial view D mesosoma in dorsal view E head and anterior mesosoma in profile, red arrow indicating omaular carina F dorsal oblique view of metasoma G prolateral surfaces of metatibia and metatarsus, with red arrows indicating longitudinal carinae H metapretarsal arolium (red arrow). Scale bars: 1 mm (A–G); 0.5 mm (H).
Sculpturing and texture. Outer surface of mandible with abundant, small, dense punctures except larger, wrinkled punctures on proximal half. Clypeus with dense, shallow punctures, puncture much smaller on apical margin than on disc. Paraocular area, supraclypeal area, and frons with large, coarse, contiguous punctures. Vertex with round, dense punctures of unequal sizes, puncture sizes smaller than those on frons. Mesoscutum with large, coarse, contiguous punctures; mesoscutellum with contiguous punctures of unequal sizes, puncture sizes smaller than those of mesoscutum (Fig.
Color. Body black except as follows: clypeus with trapezoid yellow marking except lateral and apical margins black (Fig.
Pubescence. Ventral margin of mandible with abundant, short, yellowish setae intermixed with long setae. Clypeus with short yellowish setae except sparse, erect, yellow setae on apical margin. Paraocular area, supraclypeal area, frons, and vertex with short yellowish setae. Diffuse tufts of long, dense, plumose, yellowish setae above antennal toruli. Mesoscutum and mesoscutellum with abundant short yellowish setae; mesoscutellum with long, erect, yellowish setae ventro-apically; propodeum with long, plumose, dense, yellowish setae. Prolateral surfaces of basitarsi and tarsi with dense, erect, yellowish setae; retrolateral surfaces of these same podites with tawny yellow setae. Metasomal T1–T6 with short, sparse, yellowish setae except short, yellowish setae on T6 apically; S2–S5 with long, dense, tawny yellow scopal setae.
♂: Latet.
The specific epithet is a toponym for type locality, the Ayun commune in Gia Lai Province. The name is treated as a noun in apposition.
Paraanthidium carinatum Wu, 1962: 165 [holotype ♂, paratype ♀]. Wu et al. 1988: 61.
Trachusa (Paraanthidium) carinatum (Wu): Wu 2006: 181.
Anthidiellum (Pycnanthidium) carinatum
(Wu):
Vietnam: 2♀♀, Son La, Moc Chau, Nam Kham, alt. 630 m, 22.vi.2020 [22 June 2020], Lien Thi Phuong Nguyen, Cuong Quang Nguyen, Ngat Thi Tran, Thai Van Mai leg. [1♀ in IEBR, 1♀ in
This species can be separated from the similar species A. smithii (Ritsema) by the following combination of traits: punctures of mesoscutum mesad parapsidal line dense but not contiguous; axilla laterally not reaching tangent of lateral margin of mesoscutum; and clypeus more densely, finely punctate, and posterior margin of gena not as strongly carinate posteriorly.
A nest was found in an unused wooden plank in a warehouse in Son La Province. The entrance hole of the nest was oval-shaped, with a length and a width of about 4 mm and 3 mm, respectively (Fig.
Anthidiellum (Pycnanthidium) carinatum (Wu, 1962), female A lateral habitus B dorsal-posterior habitus C facial view D mesosoma in dorsal view E mesosoma in lateral view, red arrow indicating omaular carina F prolateral surfaces of metatibia and metatarsus, with red arrows indicating longitudinal carinae G nest entrance. Scale bars: 1 mm (A, B, E); 0.5 mm (C, D, F).
Anthidiellum (Pycnanthidium) carinatum (Wu, 1962), male A lateral habitus B dorsal-posterior habitus C facial view D mandibles E mesosoma in lateral view, red arrow indicating omaular carina F apical metasomal sterna, red arrow indicating apical comb. Scale bars: 1 mm (A, B); 0.5 mm (C–F).
Holotype. Vietnam: ♀, Kon Tum, Sa Thay, Sa Son, Chu Mom Ray NP, 14°25'19"N, 107°43'54"E, alt. 653 m, 24.iv.2022 [24 April 2022], Lien Thi Phuong Nguyen, Ngat Thi Tran leg. [IEBR].
The female of this species is most similar to A. ayun (vide supra). It can be separated from that species by the tridentate mandible and in which the teeth are subequal in length not sharply pointed; by the clypeus approximately 1.6× as broad as long and with a subhexagonal yellow mark medially; the flat mesoscutellum; and the paraocular area with yellow extending along the inner ocular margin to the lower antennal torular tangent.
♀: body length (holotype) 6.5 mm. Forewing length (holotype) 6.0 mm.
Structure. Head broader than long, approximately 1.2× as broad as long (Fig.
Anthidiellum (Pycnanthidium) chumomray Tran, Engel & Nguyen, sp. nov., holotype, female. A slightly dorsal oblique lateral habitus B dorsal habitus C facial view D head and mesosoma in lateral view, red arrow indicating omaular carina E dorsal oblique view of metasoma F prolateral surfaces of metatibia and metatarsus, with red arrows indicating longitudinal carinae G metatarsus and metapretarsus, red arrow indicating arolium. Scale bars: 1 mm (A, B, D, E); 0.5 mm (C, F, G).
Sculpturing and texture. Outer surface of mandible with small, wrinkled punctures. Clypeus with shallow, dense punctures, apical margin with puncture sizes much smaller than disc. Paraocular area and supraclypeal area with large, coarse, contiguous punctures (Fig.
Color. Body black except as follows: paraocular area with yellow extending from base to lower antennal torular tangent. Clypeus with subhexagonal yellow mark medially, apical margin black. Frons with small yellow spot (Fig.
Pubescence. Ventral margin of mandible with abundant short, yellowish setae intermixed with some long setae. Clypeus, paraocular area, supraclypeal area, frons, and vertex with abundant short, sparse, yellowish setae. Tufts of long, plumose, yellowish setae above antennal toruli. Mesoscutum and mesoscutellum with abundant short yellowish setae; mesoscutellum with long, erect, yellow setae arising from beneath apical margin; propodeum with long, plumose, yellowish setae. Prolateral surfaces of basitarsi and tarsi with dense, erect, yellowish setae; retrolateral surfaces of these same podites with tawny yellow setae. Metasomal T1–T2 nearly bare, T3–T6 with short, sparse, yellowish setae except dense, yellowish setae on T6 apically; S2–S5 with long, dense, yellowish scopal setae.
♂: Latet.
The specific epithet is a toponym for the type locality, Chu Mom Ray National Park in Kon Tum Province. The name is treated as a noun in apposition.
Holotype. Vietnam: ♀, Gia Lai, Mang Yang, Ayun, Kon Ka Kinh NP, 14°13'18"N, 108°19'02"E, alt. 907 m, 26.iii.2022 [26 March 2022], Lien Thi Phuong Nguyen, Ngat Thi Tran, Cuong Quang Nguyen leg. [IEBR].
Paratypes. Vietnam: 3♀♀, same data as holotype [1♀ in IEBR; 2♀♀ in
The female of this species is most similar to that of A. (P.) carinatum (
♀: body length 6.5–7.0 mm (holotype = 7.0 mm), forewing length 6.0–6.2 mm (holotype = 6.2 mm).
Structure. Head broader than long, about 1.2× as broad as long (Fig.
Anthidiellum (Pycnanthidium) flavaxilla Tran, Engel & Nguyen, sp. nov., holotype, female A dorsolateral oblique habitus B dorsal habitus C facial view D mesosoma in dorsal view E head and mesosoma in profile, red arrow indicating omaular carina F prolateral surfaces of metatibia and metatarsus, with red arrows indicating longitudinal carinae G metatarsus and metapretarsus, red arrow indicating metapretarsal arolium. Scale bars: 1 mm (A, B, D, E); 0.5 mm (C, F, G).
Sculpturing and texture. Clypeus and paraocular area extending from base to antennal torulus with wrinkled punctures. Supraclypeal area and frons with coarse, dense punctures. Vertex with round punctures, punctures sparser than on supraclypeal area and frons. Mesoscutum with round, contiguous punctures, except polished and impunctate on short anterior-facing surface at medioapical margin; mesoscutellum with small, round, contiguous punctures (Fig.
Color. Body black except as follows: clypeus yellow except black on apical margin; supraclypeal area with yellow laterally bordering subantennal sulci; paraocular area with yellow marking extending along inner margin to about lower tangent of antennal toruli. Frons with small yellow drop above medially (Fig.
Pubescence. Apical margin of clypeus with sparse, erect, yellow setae. Clypeus, supraclypeal area, and paraocular area with short, sparse, white to yellowish setae. Antennal scape with short, yellowish setae; above antennal toruli with long, dense, plumose tuft of diffuse white setae. Frons and vertex with short, sparse, yellowish setae. Anterior, posterior, and apical margin of mandible with short yellowish setae intermixed with some longer setae. Mesoscutum and mesoscutellum dorsally with short yellowish setae; mesoscutellum ventro-apically with longer, erect, yellow setae; propodeum with long, plumose, dense, yellowish setae. Prolateral surfaces of basitarsi and tarsi with dense, erect, yellowish setae; retrolateral surfaces of these same podites with tawny yellow setae. Metasomal T1 and T3–T5 with short, sparse, yellowish setae; T2 almost bare except some short yellowish setae laterally; T6 with short yellowish setae except dense, yellowish setae on apical margin; S2–S5 with long, dense, tawny yellow scopal setae.
♂: Latet.
The specific epithet is taken from the Latin adjective flāvus (meaning, “yellow”) and the noun axilla (meaning, “armpit” or “side”), and refers to the notable yellow markings on the axillae.
Holotype. Vietnam: ♂, Kon Tum, Sa Thay, Sa Son, Chu Mom Ray NP, 14°25'19"N, 107°43'54"E, alt. 653 m, 25.iv.2022 [25 April 2022], Lien Thi Phuong Nguyen, Ngat Thi Tran leg. [IEBR]
Paratype. Vietnam: 1♂, same data as holotype [IEBR].
The male of this species is similar to that of A. (P.) coronum. The new species differs from that species by the generally dull integument (integument shinier in A. coronum); the form of the male gonostylus in which the mesal surface of mesal branch bears some long setae and the mesal branch is long with its lateral margins slightly convex, while the outer branch is shorter, slender, and nearly straight, and the apical margins of both branches are straight (the mesal branch is long, swollen, with lateral margins curved, the outer branch is shorter, slender, and nearly straight, and the apical margin of both branches is rounded in A. coronum).
♂: body length 7–7.2 mm (holotype = 7.0 mm), forewing length 6.3–6.5 mm (holotype = 6.5 mm).
Structure. Head broader than long, about 1.2× as broad as long (Fig.
Anthidiellum (Pycnanthidium) cornu Tran, Engel & Nguyen, sp. nov., holotype, male A lateral habitus B dorsal habitus C facial view D mesosoma in dorsal view E oblique dorsal view of metasoma F metasomal apex, red arrow indicating stiff peg-like and scale-like setae on apical margin of metasomal S5 G metapretarsus, red arrow indicating arolium. Scale bars: 1 mm (A, B, F); 0.5 mm (C–E, G).
Sculpturing and texture. Mandible with shallow, sparse punctures. Clypeus, basal half of supraclypeal area, and paraocular area from base to lower tangent of antennal toruli with shallow, dense, wrinkled punctures; remainder of supraclypeal area with coarse, dense punctures. Frons with coarse, contiguous punctures. Vertex with round, dense punctures. Mesoscutum with coarse, contiguous punctures, punctures larger than those on frons; mesoscutellum with coarse, contiguous, wrinkled punctures, punctures smaller than those on mesoscutum. Metasomal T1–T2 with small, round, dense punctures; T3–T5 with sparse punctures basally, blending to dense, wrinkled punctures on remainder of terga; T6 with shallow, dense punctures.
Color. Body dull black except as follows: mandible yellow except brownish black apically; clypeus yellow except tawny yellow on apical margin; paraocular area with yellow extending along inner ocular margin to lower tangent of antennal toruli; supraclypeal area yellow apically and laterally; antennal space apico-ventrally with small, dull yellow-orange marking; gena with yellow markings posterior to upper border of compound eye, extending from near tangent with top of eye to exceeding tangent (Fig.
Pubescence. Outer surface and dorsal and apical margins of mandible with short, sparse, yellowish setae; ventral margin of mandible with short, yellowish setae intermixed with longer setae. Apical margin of clypeus with some short, yellowish setae; clypeus laterally, paraocular area, and basal half of supraclypeal area with some sparse, short, yellowish setae. Antennal scape with short yellowish setae; face above antennal torulus with tuft of long, yellowish, plumose setae. Vertex with sparse, short, yellowish setae. Mesoscutum and mesoscutellum with short, yellowish setae. Propodeum with dense, long, plumose, white setae. Prolateral surfaces of metabasitarsus and metatarsus with dense, erect, white setae; retrolateral surfaces of these same podites with tawny yellow setae. Metasomal S1 with short, white tuft of setae on apical margin; S2 with longer, white tuft of setae on apical margin; S3 with long, tawny yellow tuft of setae on medioapical margin; S4 with yellowish tuft of setae on apical margin; surface of S6 with long, yellowish setae, apical margin of S6 with long, yellowish, plumose setae.
The specific epithet is the Latin noun cornū (meaning, “horn” or “antler”) and refers to the shape of the gonostyli of the male genitalia, which superficially resemble antlers.
Trachusa (Paraanthidium) coronum Wu, 2004: 545 [holotype ♀]; Wu 2006: 177.
Anthidiellum (Pycnanthidium) coronum
(Wu);
Vietnam: 1♂, Gia Lai, Mang Yang, Ayun, Kon Ka Kinh NP, 14°12'11"N, 108°18'58"E, alt. 834 m, 25.iii.2022 [25 March 2022], Lien Thi Phuong Nguyen, Ngat Thi Tran, Cuong Quang Nguyen leg. [IEBR]; 3♀♀2♂♂, Gia Lai, Mang Yang, Ayun, Kon Ka Kinh NP, 14°12'11"N, 108°18'58"E, alt. 834 m, 26.iv.2022 [26 April 2022], Lien Thi Phuong Nguyen, Ngat Thi Tran leg. [2♀♀2♂ in IEBR, 1♀ in
(hitherto undescribed). ♂: body length 7.0 mm, forewing length 6.0 mm.
Structure. Head broader than long, about 1.2× as broad as long (Fig.
Anthidiellum (Pycnanthidium) coronum (Wu, 2004), female A lateral habitus B dorsal habitus C facial view D mandibles E mesosoma in dorsal view F dorsal oblique view of metasoma G prolateral surfaces of metatibia and metatarsus H metatarsus and metapretarsus, red arrow indicating arolium. Scale bars: 1 mm (A–C, E, F); 0.5 mm (D, G, H).
Anthidiellum (Pycnanthidium) coronum (Wu, 2004), male A lateral habitus B dorsal habitus C facial view D mesosoma in dorsal view E metasomal apex in ventral view, red arrow indicating thick peg-like and scale-like setae F prolateral surfaces of metatibia and metatarsus G metadistitarsus and metapretarsus, red arrow indicating arolium. Scale bars: 1 mm (A, B, D, F); 0.5 mm (C, E, G).
Sculpturing and texture. Mandible from base with sparse, faint, wrinkled punctures except small punctures apically. Clypeus, supraclypeal area, and paraocular area from base to above tangent above antennal toruli with shallow, wrinkled punctures. Frons with coarse, dense punctures. Vertex with round, dense punctures, punctures larger than those on frons. Mesoscutum with round, dense punctures, punctures larger than those on vertex; mesoscutellum with dense, wrinkled punctures (Fig.
Color. Body black except as follows: clypeus yellow except yellow brown transparent on apical margin; mandible yellow except brownish black on apically; paraocular area with yellow marking extending along the inner margin to above the antennal socket; supraclypeal area with yellow marking as Fig.
Pubescence. Clypeus with some short, yellowish setae on apical margin; paraocular area and supraclypeal area with some sparse, short, yellowish setae; scape with short yellowish setae; face above antennal torulus and frons with tufts of long, white, plumose setae (Fig.
Characters for the key were extracted from the original descriptions of
1 | Male | 2 |
– | Female | 4 |
2 | Metatibia and metabasitasus not enlarged, prolateral surface of each with a longitudinal carina; mesoscutum with transverse yellow marks anterolaterally on anterior border | A. (P.) carinatum (Wu, 1962) |
– | Metatibia and metabasitasus enlarged, prolateral surface of each without a longitudinal carina; mesoscutum without yellow marks anterolaterally | 3 |
3 | Metasomal T1–T2 with yellow laterally; gonostylus of male forked into two unequal branches, apical margin of both branches rounded, inner branch strongly curved outward laterally; integument shiny | A. (P.) coronum (Wu, 2004) |
– | Metasomal T1–T2 black; gonostylus of male forked into two unequal branches, apical margin of both two branches straight, inner branch slightly convex laterally; integument generally dull | A. (P.) cornu Tran, Engel & Nguyen, sp. nov. |
4 | Tegula narrowly rounded posteriorly; omaular carina extending along only upper half of omaular angle; mesoscutellum less sharply margined, with distinct mediolongitudinal depression apically; forewing bicolorous, rather clear proximally and infumate apically; metasomal T5–T6 yellow | A. (C.) nahang Tran, Engel & Nguyen, sp. nov. |
– | Tegula broadly rounded or almost transverse posteriorly; omaular carina extending to venter (in some Pycnanthidium weak or even absent on lower half of mesepisterum); mesoscutellum sharply margined, with narrow mediolongitudinal depression apically; forewing not bicolorous; nearly all metasomal terga with yellow markings | 5 |
5 | Metatibia and metabasitasus not enlarged, prolateral surface of each with a longitudinal carina; metasomal T2 black | 6 |
– | Metatibia and metabasitasus enlarged, prolateral surface of each without a longitudinal carina; metasomal T2 yellow laterally | A. (P.) coronum (Wu, 2004) |
6 | Supraclypeal area, pronotal lobe, and axilla all marked with yellow | 7 |
– | Supraclypeal area, pronotal lobe, and axilla black | 8 |
7 | Medioapical margin of mesoscutum nearly straight, densely punctate up to margin; mesoscutellum with yellow on apicolateral margins | A. (P.) carinatum (Wu, 1962) |
– | Medioapical margin of mesoscutum vertical, vertical surface polished and impunctate medially; mesoscutellum black | A. (P.) flavaxilla Tran, Engel & Nguyen, sp. nov. |
8 | Clypeus approximately 1.4× as broad as long; paraocular area black; mesoscutellum convex and bigibbous apically | A. (P.) ayun Tran, Engel & Nguyen, sp. nov. |
– | Clypeus 1.6× as broad as long; paraocular area yellow to lower tangent of antennal toruli; mesoscutellum flat | A. (P.) chumomray Tran, Engel & Nguyen, sp. nov. |
Previously, two species of Anthidiellum were recorded from the northern provinces of Vietnam (
Considering the habitats in which the species were encountered, all Vietnamese species of Pycnanthidium were found on small rocks or collected in ash piles from the burning of small logs. Furthermore, all of the localities were next to small streams (Fig.
The authors are grateful to Assoc. Prof. Long Dang Khuat (Department of Insect Ecology, IEBR) for providing some of the material used for this study and to two anonymous reviewers for their constructive feedback. Several field trips conducted by Assoc. Prof. Lien Thi Phuong Nguyen and doctoral candidate Ngat Thi Tran were supported by Assoc. Prof. Vinh Van Nguyen (Faculty of Biology, VNU University of Science, Vietnam National University). This work was funded by the Vietnam Academy of Science and Technology under grant number ĐLTE00.04/22-23.