Amegilla ( Glossamegilla ) vigilans ( Smith, 1860 )

Carion, Frédéric, Gérard, Maxence, Ghisbain, Guillaume & Wood, Thomas J., 2025, Unravelling Amegilla (Glossamegilla) diversity across the Wallace Line: new species, wing morphometrics, and biogeographic boundaries (Hymenoptera, Apidae), ZooKeys 1256, pp. 1-79 : 1-79

Amegilla ( Glossamegilla) vigilans ( Smith, 1860)

Fig. 9

Material examined.

Indonesia • 1 ♂; South East Sulawesi, nr Sanggona, 1 km W of Base Camp Gn Watuwila [Sanggona] ; 200 m a. s. l.; 12–15 Oct. 1989; C. v. Achterberg leg.; Malaise trap; RMNH, RMNH.INS.1713942 - 1 ♂; [labels unreadable]; RMNH, RMNH.INS.1689433 .

Diagnosis.

Male: The male of A. vigilans usually do not have very contrasting hair bands at the apex of the terga, the tergal discs are entirely covered by pale ochraceous pubescence intermixed with sparse black hairs, the pale pubescence a little bit more dense at the apex of the terga but not forming a very contrasting hair bands (integument normally ochraceous at the apex, accentuating the pubescence, giving an impression of hair bands). Amegilla vigilans can be separated from A. himalajensis by the deep black dark clypeal marks that are sharply defined compared to the paler ivory-yellow to slightly salmon pale clypeal marks (while A. himalajensis have dark brown clypeal marks that does not contrast from each other), a dorsal pubescence of the mesosoma with black hairs intermixed (while A. himalajensis does not have any black hairs intermixed on the mesosoma) and all the terga entirely covered by ochraceous pubescence (while A. himalajensis only have T 1-2 partly or wholly and sides of T 3 covered by orange pubescence). Amegilla vigilans can be distinguished from both colour forms of A. amymone by the less extended pale clypeal marks that are either ivory-yellow or orange (but never ivory-white like in A. amymone ), the two sub-rectangular dark clypeal marks (absent in A. amymone , dark clypeal marks different than two sub rectangular areas), an ochraceous pubescence of the mesosoma (black to dark brown with many black hairs intermixed in A. amymone ) and an absence of apricot-orange pubescence on the terga (while A. amymone have apricot-orange pubescence at least on T 4-6). Amegilla vigilans can be distinguished from the trio A. insularis , A. pagdeni , and A. cinnyris by a more protuberant clypeus of approximately the width of the compound eye (while the trio have a clypeus smaller than the width of the compound eye) and a basitarsus without any black pilosity, the pilosity entirely ochraceous (while the trio have at least some black hairs on the basitarsus III). Finally, A. vigilans can be separated from A. pendleburyi by the more extended, ivory-yellow to slightly salmon, pale clypeal marks ( A. pendleburyi with clypeal mark less extended, especially the central line which is narrow, unlike in A. vigilans where the central mark is too thick to be labelled as a line), the pilosity that is paler, rather ochraceous to slightly yellow (while A. pendleburyi have a more fulvous-orange pilosity) as well as the terga entirely covered with a pale ochraceous pubescence that is denser apically, giving slightly contrasting and poorly defined hair bands ( A. pendleburyi have terga entirely and more evenly covered by fulvous-orange pilosity, leading to the absence of contrasting hair bands).

The dark form of A. vigilans is a banded form of Amegilla close to A. gigas concerning the habitus but can be separated from this species by a less protuberant clypeus of, in profile view, approximately the width the compound eye (while A. gigas have, in profile view, a clypeus that exceeds the width of the compound eye), pale orangish clypeal mark that are less extended leading to two sub-rectangular dark clypeal marks (while A. gigas have yellow, very expanded, pale clypeal marks and dark clypeal marks restricted to two small black to slightly reddish marks and two thin brown lines), a pilosity less bright in general (more ochraceous-yellow for A. vigilans while the pilosity is more fulvous to slightly orange in A. gigas ) as well as a dorsal pubescence of the dorsum of the mesosoma with more black hairs intermixed (fewer black hairs intermixed in the pilosity of the dorsum of the mesosoma in A. gigas ).

Description.

Male: Length of 17.5–18.5 mm. Interalar width of ~ 3.3–3.8 mm (shorter distance between the base of the tegulae).

Head: Labrum rectangular, slightly wider than long (18: 17–21: 20, 1.8 × 1.7 mm – 2.1 × 2 mm, thus sometimes hardly visible, can be considered squared without measurements) with a protruding base (with two brown or yellow areas, one on each side of the base) giving a curved appearance to the labrum in lateral view. Remaining labrum yellow or brownish orange (dark form), except the black transverse carina at the apex of the labrum and a narrow deep brown band at the base, brown band at the base absent in the dark form. Labrum entirely, evenly, and densely punctate with interspaces of the size of a puncture or less. Labrum entirely covered by a not very dense and ochraceous pubescence that is equal or shorter than the diameter of an ocellus. Mandibles bidentate and blunt, giving teeth a rounded apex, yellow on the basal 2 / 3 and deep brown to black on the apical 1 / 3 (darkened yellow to brown on the base for the dark form). Clypeus mainly yellow or orange with two subrectangular dark marks that can be black to slightly reddish. Clypeus entirely, finely (not very coarsely but can be coarse sometimes) and densely punctate with interspace of at most the diameter of a puncture but generally less. Clypeal carina slightly protruding, not reduced, punctate and rather blunt. Clypeus entirely, evenly, and sparsely covered by ochraceous hairs of various length with some long darker hairs intermixed. Paraocular areas protruding, yellow or orange. Paraocular areas evenly and densely punctate with interspaces ~ 1 / 2 the diameter of a puncture (sometimes hardly visible due to the pale colouration of the integument). Clypeus not strongly protuberant, in lateral view, apical margin of the clypeus of approximately the size of the diameter of the eye. Scape anteriorly yellow or darkened orange and posteriorly black. Scape entirely covered by ochraceous pubescence of various length that is denser on the sides and less dense anteriorly and posteriorly. A 2 black on the basal 1 / 2 and slightly orange on the apical 1 / 2. A 3 black on the basal 2 / 3 and orange on the apical 1 / 3 anteriorly, posteriorly black. A 4-13 paler (orange to brown) anteriorly and black posteriorly. A 3-13 entirely and evenly covered by very small, hardly visible, white pilosity. A 2 sparsely covered by ochraceous or black hair tuft that is longer than the pubescence of the next articles. A 3 longer than wide, longer than 4 + 5 but shorter than 4 + 5 + 6. A 4 shorter than wide. A 5-10 square, as long as wide. A 11-12 rectangular, slightly longer than wide (can be considered squared without measurements). A 13 not cylindrical, obliquely truncated at the apex. Frons to gena black (except a yellow or orange triangle at the margin of the frons) and rather not evenly covered by ochraceous pubescence of various length that is denser near the antennal insertions. Long black hairs intermixed in the pale pubescence near the ocelli. Presence of a relatively deep depression that goes from the middle ocellus to the pale mark of the frons, width variable. The depression hardly showing through the pubescence. Genae with very long white to ochraceous hairs (especially long under the eyes).

Mesosoma: Mesosoma entirely covered by ochraceous and dense pubescence with a variable number of black hairs intermixed (but always with at least some black hairs present) in the pilosity of the dorsum. Scutum and scutellum finely and closely punctate with interspaces of generally at most the diameter of a punctures (but can be wider on some areas of scutum and scutellum). Cuticle of the mesosoma deep black under the pilosity. Tegulae hyaline deep brown, sparsely and shallowly punctate with interspaces of at least one diameter of a puncture. Tegulae relatively densely and entirely or partially covered by ochraceous pubescence. Wings relatively sparsely covered by dark hairs on the veins and inside the cells with a denser pilosity on the veins (most parts of the cells covered by pubescence). Apex of the wings covered with very sparse and dark brown protuberances that are not similar to the hairs. Wings translucent but slightly yellow. Cuticle of all the legs deep brown to dark brown, never pale. All legs exteriorly covered by ochraceous to slightly fulvous pubescence and interiorly covered with a slightly darker to black pubescence, hind basitarsi without black hairs exteriorly. Tarsal claws of all the basitarsi bidentate with the base of the second tooth situated on the middle of the main claw. Tarsal claws very sharp, the secondary claws are very long, 2 / 3 the length of the main one. The main claws arched but without any tubercles. Apex of mid tibia with one long and thick deep brown (dark form) to black (pale form) spine which is crenulate on both sides; the spine is slightly curved at the apex. Apex of hind tibia with two long and thick deep brown (dark form) to black (pale form) spines which are crenulate on both sides; spines slightly curved at the apex.

Metasoma: For the pale form, T 1-6 entirely covered by short ochraceous pubescence that is denser on the apical margin for T 1-5, leading to slightly contrasting hair bands on these terga. Absence of dark hairs on discs of T 1-6 for the pale form. For the dark form, disc of T 1 basally and centrally covered by short black pubescence, laterally and apically covered by ochraceous short pubescence that is denser apically creating a wide but poorly contrasted hair band. T 2-5 covered by black pubescence on the disc and covered by ochraceous pubescence on the apical margin, leading to a strongly contrasted hair band. T 6 entirely covered by brown pubescence. T 1-6 entirely, evenly, and sparsely punctate with shallow punctation and interspaces of at least the diameter of one puncture. T 7 (pygidial plate) with two spine-like structures. Integument of T 1-6 deep brown to dark brown, sometimes the apical margins is paler (brown to ochraceous) it is therefore probable that the apical margins were originally deep brown to ochraceous in fresh specimen (similarly to A. pendleburyi and A. feronia ) but the integument decoloured with the time. All the sterna entirely covered by short and relatively dense ochraceous pilosity (sometimes the S 1-3 not entirely covered). Integument of sterna brown to deep brown with ochraceous apical margin (except sometimes on S 1-2). S 1-2 mainly impunctate with only some small areas with very close and shallow punctation on the centre of the sterna. Sides and apex of S 3-4 densely and evenly punctuate with interspaces of approximately the diameter of a puncture (but sometimes more and sometimes less), basal 1 / 2 of these sterna very sparsely punctuate with interspaces generally several times the diameter of a puncture. S 5-7 entirely, densely, and shallowly punctate with interspaces of approximately the diameter of a puncture. S 8 with some very small yellow hairs on the base, spine of the spiculum rounded and not curved (Fig. 9 H ). Gonocoxae mainly glabrous with only a few sparse white hairs. Intern face of the apex of gonocoxae curved. Genitalia yellow to orange, not very dark (Fig. 9 G ).

Remarks.

This description is based on only two specimens; determinators should therefore consider that intraspecific variation could occur for this species, especially on some characteristics like the clypeal marks, the colourations, or even the morphology of the mandibles. However, two forms exist inside the species A. vigilans , namely the dark and the pale forms. These two forms do not show significant structural differences but differs on colourations and the hair bands of the metasoma (Fig. 10 ). Moreover, the genitalia of both forms are the same (Fig. 10 G, H ) and both forms are therefore considered as conspecific. The colour variation observed in this species fits a broad pattern of variation in pubescence seen across other bees on Sulawesi, such as Xylocopa Latreille, 1802 ( van der Vecht 1953), though this would benefit from focused study.

A few specimens of this species (female of both forms and male of the dark form), hosted in the RMNH collection, were determined by Lieftinck in 1955 and 1956. It is therefore surprising that Lieftinck (1956) did not consider A. vigilans , even if the species was already known at the time; the reasons for the absence of this species in his work remain unknown.

Distribution.

Amegilla vigilans still appears to be restricted to the island of Sulawesi. However, the specimens studied in this paper extend the distribution of the species to the north of the island while the type was collected in the south.

Figures

Figure 9. Pictures of the male of Amegilla (Glossamegilla) vigilans (Smith, 1860) (RMNH). A. Labels of the specimen; B. Habitus in profile view; C. Face in frontal view; D. Labrum in ventral view; E. Protuberance of the clypeus in profile view; F. Terga in dorsal view; G. Genitalia in frontal view; H. Sterna 7 and 8 in dorsal view.

Figure 10. Morphological comparison between the male of both colour forms of Amegilla (Glossamegilla) vigilans (Smith, 1860) (RMNH). A., C, E, G Amegilla vigilans male pale form. B, D F, H Amegilla vigilans male dark form. A., B Habitus in profile view. C, D Face in frontal view. E, F Terga in dorsal view. G, H Genitalia in dorsal view.