Andrena (incertae sedis) tenasserima, WOOD, 2024

WOOD, T. J., 2024, Further revisions to the Palaearctic Andrena fauna (Hymenoptera: Andrenidae), Zootaxa 5483 (1), pp. 1-150 : 142-145

Andrena (incertae sedis) tenasserima spec. nov.

Figures 85A–F ; 86A–F .

HOLOTYPE: MYANMAR: Tenasserim , Thanduang [Than Daung Gyi; 19.0769 oN, 96.6803 oE], 4000 ft, 1– 30.iv.1898, ♀, leg. C.T. Bingham, ZMHB (code 9edc81).

PARATYPES: THAILAND: Chiang Mai, Doi Suthep-Pui National Park , 9.iv.2015, 3♂, 2♀, leg. M. Mikát, NMPC ; MYANMAR: same information as holotype, 1♀, ZMHB (code dcd15b) .

Description. Female. Body length: 8–9 mm ( Figure 85A ). Head: Dark, 1.4 times wider than long ( Figure 85B ). Clypeus strongly domed and flattened medially, thus weakly three-faced, irregularly punctate, punctures separated by 0.5–2 puncture diameters, interspaces shining. Process of labrum trapezoidal, 2 times broader than long, apical margin truncate. Gena exceeding width of compound eye; ocelloccipital distance 2.5 times diameter of lateral ocellus ( Figure 85C ). Vertex with surface posterior to ocellar triangle slightly but distinctly depressed, forming slight latitudinal furrow. Foveae dorsally occupying slightly more than ½ space between compound eye and lateral ocellus, separated from lateral ocellus by distance greater than diameter of lateral ocellus; foveae narrowing slightly ventrally, extending slightly beyond lower margin of antennal insertions, dorsally very slightly impressed, filled with brown hairs. Head covered with short and sparse whitish hairs, becoming brownish on vertex. Antennae basally dark, A5–12 ventrally lightened by presence of orange-brown scales; A3 exceeding A4, shorter than A4+5.

Mesosoma: Scutum and scutellum very weakly sculptured, more or less polished and shining, densely punctate, punctures separated by ≤0.5 puncture diameters ( Figure 85D ). Pronotum rounded. Mesepisternum finely microreticulate, weakly shining. Dorsolateral parts of propodeum finely reticulate, forming slightly raised network. Propodeal triangle broad, broader than long, laterally defined by narrow slightly raised carinae, internal surface with fine granular reticulation, basally and medially with weakly raised network of rugosity ( Figure 85E ). Mesepisternum laterally with whitish hairs, scutum with short and densely plumose whitish and brownish hairs, almost subsquamous; scutellum with dense tuft of longer dark brown hairs, these less strongly plumose. Propodeal corbicula incomplete, dorsal fringe composed of whitish plumose hairs, internal surface with scattered long pale hairs. Legs dark, apically becoming reddish-brown, pubescence brownish. Flocculus complete, composed of white plumose hairs; femoral scopae composed of pale simple hairs, tibial scopae composed of simple hairs, ventrally pale, dorsally dark brown. Hind tarsal claws with inner tooth. Wings hyaline, stigma and venation dark orange-brown, nervulus antefurcal.

Metasoma: Tergal discs dark, marginal areas lightened hyaline-brown ( Figure 85F ). Terga densely punctate, punctures separated by 0.5–1 puncture diameters, becoming slightly sparser on marginal areas, underlying surface polished and shining. Tergal discs with very short brown hairs, laterally with scattered pale hairs, not forming hairbands or apical fringes. Apical fringe of T5 and hairs flanking pygidial plate dark brown. Pygidial plate large, rounded triangular, medially with large swollen raised area, surface impunctate, dull.

Male. Body length: 6.5– 7 mm ( Figure 86A ). Head: Dark, 1.35 times wider than long ( Figure 86B ). Clypeus dark, domed, irregularly punctate, punctures separated by 0.5–2 puncture diameters, underlying surface polished and shining over majority of area, laterally shagreened and dull. Process of labrum small, trapezoidal, slightly broader than long, apical margin truncate. Gena equalling width of compound eye; ocelloccipital distance 1.5 times diameter of lateral ocellus. Gena, vertex, clypeus, and scape covered with short light brown hairs, paraocular areas laterally and frons with longer black hairs, weakly intermixed. Antennae basally dark, A4–13 ventrally lightened orange; A3 equalling A4.

Mesosoma: Scutum and scutellum with fine granular shagreen, medially weak and almost shining, laterally and anteriorly stronger, almost dull; surface punctate, punctures separated by 0.5–1 puncture diameters ( Figure 86C ). Pronotum rounded with faint hint of humeral angle. Mesepisternum microreticulate, dull to weakly shining ventrally. Dorsolateral parts of propodeum finely reticulate, forming slightly raised network of wrinkles. Propodeal triangle broad, broader than long, laterally defined by narrow slightly raised carinae, internal surface with fine granular reticulation, basally and medially with weakly raised network of rugosity ( Figure 86D ). Mesepisternum laterally with light brown plumose hair, becoming slightly shorter on scutum and scutellum. Legs dark, apical tarsal segments lightened orange, pubescence whitish to light brown. Hind tarsal claws with inner tooth. Wings hyaline, stigma brown, venation orange-brown, nervulus antefurcal.

Metasoma: Tergal discs dark, marginal areas with apical rims narrowly lightened hyaline-brown ( Figure 86E ). Terga densely punctate, punctures separated by 0.5–1 puncture diameters, becoming slightly sparser on marginal areas, underlying surface polished and shining. Tergal discs with very short brown hairs, laterally with scattered pale hairs, not forming hairbands or apical fringes. T6–7 with long brown hairs overlying pygidial plate of T7. S8 narrow, columnar, ventrally with strong laterally-projecting fringes of orange hairs, these not projecting apically, hence giving impression of fishtail-like apex to S8. Genital capsule slightly elongate, gonocoxae produced into pointed and apically diverging teeth ( Figure 86F ). Gonostyli flattened apically, apexes roughly triangular with strongly raised internal margin, outer surface weakly punctate. Penis valves slightly inflated medially, occupying slightly less than ½ space between gonostyli, gently narrowing apically.

Diagnosis. Andrena tenasserima presents a combination of characters that do not currently allow for confident subgeneric placement. Morphologically, due to the head with relatively long ocelloccipital distance (2.5 times the diameter of a lateral ocellus, Figure 85C ) and vertex which is slightly but distinctly depressed, forming a slight but visible furrow along the posterior margins of the hind ocelli, facial foveae that dorsally extend to the anterior margins of the lateral ocelli, gena broader than the width of the compound eye, broad and relatively unsculptured propodeal triangle ( Figure 85E ), and lack of any other distinctive characters, it can be placed close to the group of subgenera Calomelissa Hirashima & LaBerge, 1963 , Oreomelissa Hirashima & Tadauchi, 1975 , and Tarsandrena . Based on limited taxon sampling, these three subgenera form a monophyletic and relatively basal clade within Andrena ( Pisanty et al. 2022b) . The greatest diversity of these three subgenera is clearly found in Asia, predominantly East Asia, with only three species entering the West Palaearctic ( Xu & Tadauchi 1995; 1999; Xu et al. 2000; Gusenleitner & Schwarz 2002).

These subgenera are not strongly defined morphologically, with many of the highlighted characters variable (e.g. head length, humeral angle, tergal sculpture, foveae width, forewing venation; Xu et al. 2000). Further taxon sampling is needed to establish whether retention of the three subgenera is merited. In this context, placement is closest to the subgenus Oreomelissa due to the shape of the vertex, which is long and clearly impressed along the posterior margins of the hind ocelli. However, there are some differences; in most Oreomelissa species, the facial foveae extend further dorsally, reaching to the posterior margins of the lateral ocelli, and are noticeably impressed, whereas in A. tenasserima the facial foveae are only very slightly impressed dorsally. Furthermore, most Oreomelissa species have the dorsal (horizontal) section of the propodeum relatively elongate, so in dorsal view the propodeal triangle is about as long as broad. In contrast, in A. tenasserima the dorsal section of the propodeum is relatively short and so the propodeal triangle is clearly broader than long. The female pronotum also usually presents a weak humeral angle (though this is variable), but this is lacking in A. tenasserima . Moreover, the male clypeus and lower paraocular areas are black ( Figure 86B ; yellow or white-marked in Oreomelissa ). Consequently, A. tenasserima is cautiously associated with the subgenus Oreomelissa , but is classified as incertae sedis until genetic data are available.

Diagnosis is provided against Chinese Oreomelissa species which are currently known to extend south to the northern part of Yunnan province in southern China ( Xu et al. 2000), approximately 1000 km north of the locus typicus of A. tenasserima , and which are consequently likely to be present in northern Myanmar. Due to the broad gena (broader than the width of the compound eye), lack of spines along the posterior face of the hind femur (with spines in A. submontana Wu, 1982 , A. malickyi Gusenleitner & Schwarz, 2000 , and A. setosifemoralis Wu, 2000 ), polished and densely punctate terga (punctures separated by 0.5–1 puncture diameters; in A. fani Xu & Tadauchi, 2000 with terga shagreened with obscure and scattered punctures, punctures separated by 1–3 puncture diameters), and dark male face and genital capsule with relatively narrow penis valves, separation is straightforward. Additionally, A. tenasserima can be separated from all of these species by the only weakly impressed facial foveae and the broader than long propodeal triangle.

Remarks. Charles Thomas Bingham (1848–†1908) was an Irish military officer and naturalist. He was posted in what is now Myanmar in 1877, and developed an interest in entomology. He later worked in the NHMUK, and edited the first two Hymenoptera volumes of the Fauna of British India ( Bingham 1897; 1903) and described two Andrena species from India ( Bingham 1908). For A. tenasserima, Bingham indicated “Tenasserim” on the labels, but some geographers separate the Tenasserim Range from the more northerly Dawna Range, and others consider them collectively as “Dawna Tenasserim”. The collecting locality of Than Daung Gyi falls within the Dawna Range. The village itself was used by the British during the colonial period as a summer retreat from the heat of the lowlands, as it is found above 1000 m in elevation, and hence has a cooler climate more suited to Andrena species; this is the first Andrena species reported from this predominantly tropical country ( Ascher & Pickering 2023), with only A. (Malayapis) chrysochersonus Baker, 1995 known from further south in south-east Asia (Cameron Highlands, Malaysia).

Bingham collected extensively in Burma (now Myanmar), writing in 1897 that the majority of his collecting in British India was carried out during the preceding 12 years in Burma and Tenasserim ( Bingham 1897: xiii). He described other bee species from the Tenasserim region (e.g. Anthophora fraterna Bingham, 1897 ; Megachile elizabethae Bingham, 1897 ; Protosmia burmanica ( Bingham, 1897)) , and mentioned numerous species records from this region for other bees, but none for Andrena . His collection was split between the NHMUK and the ZMHB, with the latter containing the specimens described here in a box of undetermined material.

Etymology. From the Tenasserim Hills or Tenasserim Range that broadly run along the border between Myanmar and Thailand (the name originally deriving from the Malay Tanah Seri, meaning glowing land). It is a noun in apposition.

Distribution. Central Myanmar and north-western Thailand.

Figures

FIGURE 85. Andrena (incertae sedis) tenasserima spec. nov. female. A. Habitus, lateral view; B. Face, frontal view; C. Vertex, dorsal view; D. Scutum, dorsal view; E. Propodeum, dorsal view; F. Terga, dorsal view.

FIGURE 86. Andrena (incertae sedis) tenasserima spec. nov. male. A. Habitus, lateral view; B. Face, frontal view; C. Scutum, dorsal view; D. Propodeum, dorsal view; E. Terga, dorsal view; F. Genital capsule, dorsal view.