Anthidiellum (Clypanthidium) nahang Tran, Engel & Nguyen, 2023

Tran, Ngat Thi, Engel, Michael S., Nguyen, Cuong Quang, Tran, Duong Dinh & Nguyen, Lien Thi Phuong, 2023, The bee genus Anthidiellum in Vietnam: descriptions of five new species and the first male of Anthidiellum coronum (Hymenoptera, Megachilidae), ZooKeys 1144, pp. 171-196 : 171

Anthidiellum (Clypanthidium) nahang Tran, Engel & Nguyen sp. nov.

Fig. 1A-F

Type material.

Holotype. Vietnam: ♀, Tuyen Quang, Na Hang, v.2018 [May 2018], malaise trap, Long Dang Khuat leg. [IEBR].

Diagnosis.

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 ).

Description.

♀: body length (holotype) 9.5 mm, forewing length (holotype) 9 mm.

Structure. Head broader than long, approximately 1.2 × as broad as long (Fig. 1C ). Compound eyes 2.8 × as long as broad, 1.5 × genal width. Mandible quadridentate, interspace between first two teeth broad, about 2 × that of interspace between second and third tooth (Fig. 1C ). Clypeus slightly convex medially, about 1.9 × as broad as long. Supraclypeal area slightly convex medially. Scape slender, about 4.5 × as long as broad; pedicel approximately as broad as long and 1.1 × length of F1; F1 as broad as long and subequal to length of F2+F3; F4-F6 longer and subequal in length, longer than F3; F7-F9 subequal in length, longer than F4; F10 longest flagellomere, about 1.6 × as long as broad. Mesosoma approximately 1.2 × as broad as long; mesoscutum with postero-lateral corner forming an obtuse angle; mesoscutellum short, convex in dorsal view and emarginate medio-apically (Fig. 1D ). Forewing with two submarginal cells, first submarginal cell broader than second submarginal cell. Metapretarsus with arolium (Fig. 1G ). Metasoma curved ventrally, giving metasoma arched appearance in profile (Fig. 1A ).

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. 1C ). Supraclypeal area and paraocular area with round, dense, nearly contiguous punctures, puncture sizes larger and rougher than on clypeus. Vertex with large, coarse, dense, contiguous or nearly contiguous punctures. Mesoscutum with round, distinct, dense, nearly contiguous punctures; mesepisternum with punctures as on mesoscutum; mesoscutellum with punctures as on mesoscutum except some slightly larger and coarser (Fig. 1D, E ). Metasomal T1-T4 with round, small, dense punctures, T5-T6 with wrinkled punctures.

Color. Body black except as follows: clypeus with yellow markings laterally, paraocular area with yellow markings baso-laterally; mandible with yellowish-brown apex (Fig. 1C ); forewing rather transparent basally and dark brown apically (Fig. 1A, B ); metasomal T5 yellow except black baso-laterally and on apical margin, T6 yellow (Fig. 1F ).

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. 1C ). Frons with short white setae. Vertex with short blackish setae. Mesoscutum with short, dense, blackish setae on dorsal surface and yellowish setae laterally, mesoscutellum with short, dense, blackish setae. Meso- and metatrochanters with dense, yellowish setal tufts ventrally; prolateral surface of mesotibia with short brownish setae, retrolateral surface of mesotibia and both pro- and retrolateral surfaces of mesobasitarsus with long brownish setae; prolateral surface of metatibia with short blackish setae; retrolateral surface of metatibia with short brownish setae; both pro- and retrolateral surfaces of metabasitarsus with long blackish setae. Metasomal T1-T4 with short blackish setae; T5-T6 with short yellowish setae; T6 apically with short, soft, feathery, yellowish white setae (Fig. 1F ); S2-S6 with long, dense, white to yellowish scopal setae (Fig. 1A ).

♂: Latet.

Etymology.

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.

Subgenus Pycnanthidium Pycnanthidium Krombein, 1951

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.

Figures

Figure 1. 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).