Amegilla ( Glossamegilla ) gigas Friese, 1922

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) gigas Friese, 1922

Fig. 11

Type material.

Lectotype: Asia Arch. [ Indonesia] • 1 ♀; Wetter [Pulau Wetar] ; 3 Apr. 1901; Kühn leg.; ZMHB, http://coll.mfn-berlin.de/u/837c94. [images examined only]

Additional material examined.

Timor [ Timor-Leste] • 1 ♂; Same ; 27 Dec. 1965 – 14 Jan. 1966; R. N. Ierreira leg.; RMNH.INS.1713966 .

Remarks on the type series of Friese.

Friese (1922: 61) mentioned two females in his type series, one from Wetar ( Lesser Sunda islands) and one from Sumatra ( Deli, eastern Sumatra). However, these two specimens are on each side of the Wallace Line which is, with the current information on the distribution of Glossamegilla , doubtful. Moreover, the ZMHB seems to only host the specimen from Wetar while the specimen from Sumatra was not found (P. Rasmont, pers. comm., 2 December 2024). Therefore, without further information, the specimen from Sumatra cannot be considered as conspecific with A. gigas , especially because of its doubtful locality compared to everything that is currently known on the subgenus Glossamegilla . The specimen from Wetar ( March 1901, leg. Kühn) conserved in the ZMHB (examined by photograph) is considered to be the lectotype following an unpublished designation by P. Rasmont in 2024. This designation decisively fixes the locus typicus as the island of Wetar.

Diagnosis.

Male: The male of A. gigas shows strongly contrasting hair bands, with only black hairs on the discs T 2-4 while T 1 is entirely covered by pale fulvous pubescence. Amegilla gigas differs from A. jacobi and A. sumatrana by the wider and more colourful (fulvous in A. gigas , white to slightly ochraceous in A. jacobi and A. sumatrana ) hair bands at the apex of the terga as well as a slightly smaller black-haired area. Amegilla gigas also differs from A. feronia and A. cyrtandrae by the more strongly protuberant clypeus of, in profile view, ~ 1.3 × bigger than the width of the compound eye ( A. feronia and A. cyrtandrae have a less protuberant clypeus that is, in profile view, smaller than the width of the compound eye) and a larger body size of ~ 18 mm (while A. feronia and A. cyrtandrae are ~ 15–17 mm maximum). Amegilla gigas can be distinguished from A. floresiana sp. nov. by the labrum as long as wide (1: 1, while A. floresiana sp. nov. have a labrum slightly wider than long; ~ 17: 16–19: 18), a coarser punctation of the clypeus that is not very sparse with interspaces of at most the diameter of a puncture ( A. floresiana sp. nov. have a fine punctation that is also very sparse with large interspaces of at least the diameter of a puncture) as well as the tergal hair bands narrower and more sharply defined with the black-haired area on the tergal discs larger and more consistently present ( A. floresiana sp. nov. have wider and poorly defined tergal hair bands at the apex of the T 2-4 with a small black-haired basal part the discs, sometimes some or all the terga do not have a black-haired area and are entirely covered by the pale pubescence). Finally, A. gigas can be distinguished from the dark form of A. vigilans by a more protuberant clypeus of ~ 1.3 × bigger than the diameter of the eyes (1: 1 in A. vigilans ), yellow clypeal marks that are very extended with only a small dark mark and one narrow brown line on each side of the clypeal carina ( A. vigilans have pale yellow to orange less extensive pale marks and two sub-rectangular black marks), a pilosity in general more bright (rather fulvous to slightly orange in A. gigas , ochraceous in A. vigilans ) as well as a dorsal pubescence of the mesosoma without or with only few black hairs intermixed (while A. vigilans have more black hairs intermixed in the dorsal pubescence of the mesosoma).

Description.

Male: Length of 18 mm. Interalar width of ~ 3.6 mm (shorter distance between the base of the tegulae).

Head: Labrum square, as wide as long (1: 1, 2 × 2 mm), with two slightly protruding pale brownish areas at the base, remaining labrum entirely lemon-yellow except for the dark brown to black transverse carina at the apex of the labrum. Labrum entirely but sparsely punctate with interspaces wider than the diameter of a puncture, the interspaces become narrower while going towards the apex of the labrum (interspaces of ~ 1 / 2 the diameter of the punctures). Labrum entirely covered by yellow pubescence longer than the diameter of an ocellus. Mandibles bidentate and slightly blunt (not very sharp) at the apex, the bases lemon-yellow, similarly to the labrum. Face mostly lemon-yellow, only the clypeus with four dark brown to black mark (two lines and two subrectangular areas) that resume the dark clypeal marks. Clypeus entirely and evenly punctate with relatively small interspaces of approximately the diameter of a puncture. Clypeal carina slightly protruding, blunt and impunctate. Clypeus mainly covered by black and very sparse hairs, except at the apex, near the labrum where the pubescence is yellow and denser. Paraocular areas protruding and yellow, almost entirely punctate (same punctation as on the clypeus) except some wider clear interspaces on the margin of the paraocular areas and on their centres. Clypeus protuberant, protuberance of the margin of the clypeus of ~ 1.3 × bigger than the diameter of the eyes (while A. vigilans have a clypeus of approximately the size of the eye). Scape anteriorly orangish yellow and posteriorly black, covered entirely by fulvous pilosity. A 2-13 black or at least very dark and covered by very small white hairs that are hardly visible. A 3 longer than wide, longer than 4 + 5 but slightly shorter than 4 + 5 + 6. A 4-12 squared, approximately as long as wide or a little bit longer than wide. A 13 not cylindrical, obliquely truncated at the apex. Frons to gena black (except a yellow triangle at the margin of the frons) and covered (but not evenly) by fulvous pubescence.

Mesosoma: Mesosoma entirely and evenly covered by fulvous to slightly orange pubescence, without any black hairs intermixed in the pilosity of the dorsum. As the pubescence is dense, the punctation underneath can sometimes not be seen. Scutum and scutellum finely and closely punctate (deep punctures) with very small interspaces (≤ 1 / 2 the diameter of a punctures). Cuticle under the pilosity deep black. Tegulae hyaline deep brown. Wings sparsely covered by dark hairs on the veins and inside the cells with a denser pilosity on the veins. Apex of the wings covered with very spars and dark brown protuberances that are not similar to the hairs. Wings translucent but slightly yellow. All legs with a dark brown cuticle, exteriorly covered by fulvous to slightly orange pubescence and interiorly covered by dark brown to black pubescence. Tarsal claws of all the basitarsi bidentate. Apex of mid tibia with one long and thick brown spine which is crenulate on one side and smooth on the other side. Apex of hind tibia with two long and thick brown spines which are crenulate on one side and smooth on the other side.

Metasoma: T 1 entirely covered with long fulvous pubescence that is denser and shorter on the apical margin, forming a hair band that does not contrast very much in the surrounding pilosity. Discs of T 2-4 dark haired with whitish to fulvous hair bands on the apical margins. Disc of T 2 laterally with fulvous hair tufts covering all the length of the disc but that does not expand very much transversally. Discs of T 3-4 laterally with small, not very expanded, fulvous hair tuft. T 5 and following entirely black haired. Discs of T 1-5 sparsely punctate with shallow punctations and interspaces generally between 1.5 to twice the diameter of a puncture. Apical margin of T 1-5 impunctate. T 6-7 entirely and less sparsely punctate, punctation of T 6 as shallow as previous terga but punctation of T 7 deeper. T 7 ending in two protruding spines at the apex with a curve between the two spines. Integument of the terga entirely black except for T 6-7 that have a dark brown integument. S 1-6 mainly black haired. S 1-4 with tuft of not very expanded ochraceous hairs on the sides of the apical margin, S 5 black haired and S 6 with a band of ochraceous hairs on the apical margin. S 1-3 with a deep brown integument, S 4-6 with a darker brown to black integument. S 1-3 very sparsely punctate of the disc with only a few punctures except on the sides where there is a denser punctation under the hairs. S 4-5 more densely punctuate with an evenly shallow punctation (interspaces of approximately the diameter of one puncture). S 6 densely punctuate on the sides and with only a few punctures on the centre of the disc. S 7-8 with some very small yellow hairs on the base, spine of the spiculum very sharp and backwardly curved (Fig. 11 H ). Gonocoxae mainly glabrous with only a few sparse white hairs. Intern face of gonocoxae crenulate. Genitalia brownish at the base, tending yellow while going toward the apex (Fig. 11 G ).

Remarks.

This description is based on only one specimen; 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. Moreover, some doubts exist concerning the sex association between the male and the female. Indeed, the male is similar to the lectotype and shows a close distribution, without being identical (take care that the unmatching distribution can be a bias from the undersampling in the region). The islands of Timor and Wetar are separated by a straight of ca 50 km, although the small island of Ataúro forms a potential intermediate step, separated by 26 km from Timor (at Dili) and 13 km from Liran island, just to the south-west of Wetar. Some morphological differences exist between these two specimens. These differences consist mainly of the paraocular area being yellow (ivory-white for the female), yellow covering a greater surface of the face (clypeus almost entirely yellow, big yellow mark between the antennae while the female has an almost entirely dark clypeus and a smaller yellow triangle between the antennae), a labrum entirely yellow (female has a partially dark labrum), A 3 longer than 4 + 5 but slightly shorter than 4 + 5 + 6 (female has the A 3 as long as 4 + 5 + 6 + 7), and a more protuberant clypeus of 1.3 the width of the compound eye (female has a clypeus of approximately the width of the compound eye) (females characters are based on images of the lectotype and the description of Friese 1922: 61). All these small differences are currently considered as intraspecific variations and dimorphism but bring some doubts to the pairing of both sexes. New collections and genetic studies should be performed in order to give a definitive answer for this case but, while waiting for these, the specimens from Timor is considered as the male of A. gigas .

Distribution.

With the discovery of the supposed male of A. gigas , the distribution of this species is enlarged to the island of Timor and more specifically the country of Timor-Leste. The species was originally known from the island of Wetar ( Friese 1922). As discussed for the type series, the specimen from Sumatra is not considered as conspecific; therefore, this species is not distributed in Sumatra.

Figures

Figure 11. Pictures of the male of Amegilla (Glossamegilla) gigas (Friese, 1922) (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.