Exanthidium guichardi Pasteels, 1980

Kasparek, Max, 2021, The bee genus Pseudoanthidium: revision of the subgenus Exanthidium with the description of a new species (Apoidea: Megachilidae), Fragmenta entomologica 53 (2), pp. 333-346 : 340-341

Exanthidium guichardi Pasteels, 1980

Holotype. Male, Oman: Wadi Ouryat, Ag. St., 5.iii.1976 (ad-Dachiliyya governorate, approx. 22°55’N, 57°09’E), K.M. Guichard leg.; https://data.nhm.ac.uk/dataset/collection-specimens/resource/05ff2255-c38a-40c9-b657-4ccb55ab2feb/record/9096058; photograph ( Fig. 9A ) examined.

Other material examined. UNITED ARAB EMIRATES: 1 ♂, al-Ain al-Fayda (24°05’N, 55°40’E), 8 Apr 2005 (listed by Dathe 2009 under P. enslini ). Deposited in the A. van Harten collection in the DEI ( DEI130 ) ( Fig. 9 ) . OMAN: 1♀, NW of Ibri, S of Dank , 9 March 2015, M. Snižek leg. ( Fig. 10 ) ( OLL) .

Material not examined. UNITED ARAB EMIRATES: 1 ♀, Fagsha, Fujairah, 21 Apr 1988, I. Hamer leg., D. Baker det. (Snow Entomological Collection, Ohio), www.gbif.org/occurrence/785011857 (also listed by Dathe 2009). This material is listed under P. enslini and is tentatively assigned here to P. guichardi .

Structurally similar to P. enslini , but entire integument light yellow except for scutellum and face (dominant ground colour in P. enslini black). Yellow tergal bands interrupted in the middle in P. enslini , uninterrupted in P. guichardi . In P. guichardi , the tergal discs have an almost step-like elevation over the depressions with a clear, albeit somewhat jagged border line (best seen medially on T2- T4). By contrast, the transition from the disc to the depression is inconspicuous and smooth in A. enslini .

Male ( Fig. 9 ). 7 mm. Head: Light yellow except for black in the upper face from above antennal sockets to hind ocelli; yellow spot below anterior ocellus (present in DEI specimen, absent in holotype); clypeus bell-shaped; head densely punctate throughout except for marginal areas of clypeus which are smooth; dense, long, silvery, adpressed hair covering face; vertex and gena almost hairless; mandible pale yellow, sparsely punctate, with three black teeth; scape yellow; flagella reddish-brown, upper side of distal flagella grey-brown; preoccipital ridge angulate.

Mesosoma : Light yellow; scutum black with anterolateral yellow stripe in holotype, but in DEI specimen, anteri- or third entirely reddish brown and laterally yellow; pronotal lobe with high lamella; scutellum black anteromedially (holotype) and yellow posteriorly (entirely yellow with only some inconspicuous reddish tone anteromedially in DEI specimen); posteromedially slightly depressed; posterior margin transparent, jagged; widely rounded in dorsal view; sharp-edged in lateral view; axilla triangular, yellow.

Metasoma: Yellow except for the declivous anterior part of T1 which is black in the holotype and light brown in the DEI specimen; tergal bands on discs unbroken; depressions yellowish-brown; marginal areas smooth, transparent and slightly turned upwards; discs conspicuously elevated over depressions, the two areas separated by a distinct jagged line; punctation on discs dense and coarse, on depressions dense and fine; T4 bulging laterally, T5 with blunt tooth laterally, T6 with flat, transparent hooklike tooth laterally; T6 bulging mediolaterally; T7 long with deep median emargination; margins broadly transparent; S6 laterally with strongly sclerotised wings; apex thin and transparent, bilobed; apex of (hidden) S8 truncate.

Female ( Fig. 10 ). Structurally very similar to the female of P. enslini , but distinguished by colouration: almost entirely yellow and light reddish-brown except for black maculation around ocelli and between ocelli and antennal sockets, and some black remnants at anterior and posterior margin of scutum. Face and vertex light reddish-brown, lower face including clypeus, and gena yellow; T1-T5 with broad yellow bands and light brown depressions.

Remarks. The species is distinguished from P. enslini according to Pasteels (1980) by a bilobed S 6, a relatively broad gena and a relatively long distance of the hind ocellus from the preoccipital ridge. However, both species have a bilobed S 6, only slightly less emarginate in P. enslini . Also the difference of the width of the gena as compared to the width of the eye is moderate and the difference in the postocelli-preoccipital distance could not be confirmed when compared with P. enslini holotype. These traits may thus fall into individual variation and do not have diagnostic value. Also additional morphological differences such as the presence of a lateral bulge on T6 vs. a blunt lateral tooth in P. enslini cannot be used as specific characters until the full variation is known.

Attempts to retrieve DNA from the UAE specimen for a genetic barcoding were not successful.

Distribution. Eastern Arabian Peninsula around the Gulf of Oman ( Oman and United Arab Emirates) ( Fig. 15 ).

Figures

Fig. 9 – Pseudoanthidium guichardi Pasteels, 1980. Male. A, Holotype from Oman (NHMUK); B-H, Male from United Arab Emirates (DEI); A-B, Habitus ventral; C-D, Head and mesosoma in dorsal view; E, Head in frontal view; F, Apical terga; G, Habitus lateral; H, Apex of metasoma in ventral view.

Fig. 10 – Pseudoanthidium guichardi Pasteels, 1980. Female from Oman (OLL).

Fig. 15 – Distribution of Pseudoanthidium deserticolum sp.n., P. enslini, P. pictipes, and P. wahrmanicum.