Eoanthidium (Hemidiellum) riparium (Cockerell, 1929) Nalinrachatakan & Ascher & Kasparek & Traiyasut & Thanoosing & Warrit, 2023

Nalinrachatakan, Pakorn, Ascher, John S., Kasparek, Max, Traiyasut, Prapun, Thanoosing, Chawatat & Warrit, Natapot, 2023, A review of the anthidiine bees (Apoidea, Megachilidae) in Thailand, ZooKeys 1186, pp. 235-284 : 235

Eoanthidium (Hemidiellum) riparium (Cockerell, 1929) comb. nov.

Figs 6 , 7 , 8

Dianthidium riparium Cockerell, 1929: 204 (♀). Holotype from Nan, Thailand (NHMUK, examined).

Dianthidium chinensis Wu, 1962: 167-168, figs 22-26 (♂) (syn. nov.). Type from Yunnan, Xishuangbanna, 9 Apr 1955.

Eoanthidium (Hemidiellum) semicarinatum Pasteels, 1972: 112-116 (♀, ♂) (syn. nov.). Female holotype and male paratypes from Pondicherry State, Karikal, India (NBC, examined).

Eoanthidium (Hemidiellum) punjabensis Gupta & Sharma in Gupta 1993: 37-39, fig. figs 65-77, 79 (♂) (syn. nov.). Male holotype from Pathankot, Punjab, 4 Jun 1991.

Eoanthidium (Hemidiellum) punjabense Gupta & Sharma in Gupta 1993: 37-39, figs 65-77, 79, mandatory change for gender agreement.

Eoanthidium ( Eoanthidium s. str.) chinensis (Wu, 1962): Wu, 2006: 134, fig. 66 (syn. nov.).

Material examined.

39 (16♀, 23♂). India: Karnataka: Bangalore, GKVK, 1♀, 2 Apr. 1982, Ghorepade, 1♂, 15 Apr. 2013, Girish, (UAS); Mysore, 1♀, 19 Apr. 2009, 2♀, 16 Apr. 2009, 1♂, 5 Apr. 2009, Dhanyavathi. (UAS); 1♂, Mandya, 1 May 2014, Veereshkumar (UAS; same specimens as Kumar et al. 2017); 1♂, Coimbatore, 3 Mar. 1950, P. Susai Nathan [ Eoanthidium semicarinatum Past. D.B. Baker det. 1982 / D.&M. Baker collection KUNHM#2004-en-004 / SEMC0975139] (SEMC25); 1♂, Madras State Coimbatore (alt. 1,400 m) Apr. 1962, P. Susai Nathan [ E. semicarinatum det. Pasteels 1969 / PARATYPE / R.M. N.H.B. 24.136] (RBINS113); 1♂, Hisar, 15 May 1986, A. Rahman [D.&M. Baker collection KUNHM#2004-en-004 / SEMC0975140] (SEMC28); 1♀, Karnataka Malaksamudra Tank, 2 Mar. 1984, K. Ghopada [B21 / Ghorpade collection Bangalore / E. (Hemidiellum) semicarinatum det. C.G. Michener / SEMC1321747 KUNHM-ENT] (SEMC41); Pondicherry State Karikal, Mar. 1962, P. Susai Nathan, 1♀ [ E. semicarinatum n. sp. Pasteels det. 1969 / HOLOTYPE / RMNH.INS 943212) (NBC001), 1♂ [ E. semicarinatum n. sp. J.Pasteels det. 1969 / ALLOTYPE / PARATYPE / RMNHS.INS 943188] (NBC033), 1♂ [ E. semicarinatum n. sp. J.Pasteels det. 1969 / PARATYPE / RMNHS.INS 943189] (NBC034); Laos (new record): Champasak, Si Phan Don, 3♀, 11♂, Don Det, 20 Jan. 2015, N. Warrit et al. (CUNHM: BSRU-AA-1220-1222, 1224-1226, 1228-1230, 1232-1234, 1236-1237); 1♀, KHONG ISLAND [= Don Khong], 25 Oct. 2008, D.W. Baldock, E. Popov Hemidiellum Pasteels Hemidiellum riparium (Cckll.) det. Risch, 2008 (NHMUK: BMNH-ENT-2017-196 (ACQ)); Myanmar (new record): 1♀, Dawei city (13°50.933'N, 98°9.647'E, alt. 15 m), 3 May. 2018, N. Warrit et al. (CUNHM: BSRU-AA-6896); Pakistan: Punjab, Lahore , 2 May 1979, P.H.B. Baker, 1♂, [ E. semicarinatum Past. D.B. Baker det. 1982 / D.&M. Baker collection KUNHM#2004-en-004 / SEMC0975141] (SEMC26), 1♂, [D.&M. Baker collection KUNHM#2004-en-004 / SEMC0975140] (SEMC27), 4♀, [D.&M. Baker collection KUNHM#2004-en-004 / SEMC0975143-0975146] (SEMC29-32); Thailand: 1♀, type, nan. Siam Jan. 7. ( Cockerell ) [= Nan province, 7 Jan, year is not indicated on the label, but Cockerell’s work was published in 1929], Dianthidium riparium TYPE: Ckll., B.M. TYPe HYM. 17?? [?? = may be “01” but is difficult to read] 1939, Brit. Mus. 1933-567 (NHMUK 014026126); 1♂, Chiang Mai, Chiang Dao District , Chiang Dao Wildlife Sanctuary (19°24'53.2506"N, 98°54'53.2218"E, alt. 541 m) specimen from TIGER project T-5776, 19/ 25 Feb 2008, Songkran & Apichart (CUNHM: BSRU-AB-4358); 1♂, Lampang, Mueang Pan District , Chae Son National Park (18°49'44.2488"N, 99°28'15.1026"E, alt. 509 m), specimen from TIGER project T-5413, 7/ 14 Apr 2008, Boonruen & Acharaporn (CUNHM: BSRU-AB-4360).

Distribution.

China (Yunnan, new record), India (Haryana: Hisar, Karnataka: Bangalore, Koppala, Mysore, Mandya, Tamil Nadu: Karikal, Coimbatore, Punjab: Pathankot), Laos (Champasak, new record), Myanmar (Dawei, new record), Pakistan (Punjab: Lahore), Thailand (Chiang Mai (new record), Lampang (new record), Nan (new record)).

Diagnosis.

The species exhibits pale yellow maculation, remarkably on supraclypeal area (which is reduced medially into a unique shape or absent (Fig. 6 ), as shown for Laotian, Myanmarese, Thai holotype of Dianthidium riparium Cockerell, 1929 and Chinese D. chinensis Wu, 1962), two paramedian yellow stripes on the scutum, and wide yellow bands on all terga which is often a little disrupted at the median on T1-T5 and also T6 in males. In males, T7 with a broadly rounded lateral lobe and a small median notch with cutting end. Genitalia as in Fig. 6H-J , gonostylus in ventral with inner swollen base, apodeme of penis valves extremely extended.

Floral associations.

The record of Chinese element ( Wu 1962) mentioned " Eupatoreae sp." (today recognized as Eupatorieae , Asteraceae ) from China. Noteworthy, the group includes the globally invasive "Tropical whiteweed" ( Ageratum conyzoides L.), that also widely distributed in South China and locally used as a biocontrol plant to enhance the productivity of farmland ( Huang et al. 2011). The study from India by Gorain et al. (2012) reported the visitation of Eoanthidium punjabense on "ghaf" tree ( Prosopis cineraria (L.) Druce ( Fabaceae )).

Remarks.

Although the specimens from China, Laos, Myanmar, and Thailand are different in their coloration compared to the type bearing the name Eoanthidium (Hemidiellum) semicarinatum , some characters and male genitalia are unique among the genus, and obviously comparable (see also the figures in Wu 1962; Pasteels 1972; Kumar et al. 2017). The female of " Dianthidium riparium " was described by Cockerell (1929), but he did not refer to its juxta-antennal carina, the main character of the genus Eoanthidium , and Eoanthidium was designated later ( Popov 1950). Likewise, the description and the illustrations of Eoanthidium (Eoanthidium) chinensis (Wu, 1962) ( Wu 1962: figs 23-26; 2006: fig. 66) and photographs of further material held in IZCAS provided by Ze-Qing Niu are adequate to synonymize this taxon with Eo. riparium .

When compared with " Eo. semicarinatum " specimens from India and Pakistan, it is evident that the individuals from Southeast Asia and China (Yunnan) are larger and darker, and tend to come with a reduction in pale yellow facial maculation in supraclypeal area, frons, and on mesepisternum, scutum, and scutellum (Fig. 7 ). Most of the paramedian band on the scutum is obscure, narrow, and not connected to the anterolateral mark, while the yellow mark on female hindlegs is not fully extended as in Indian and Pakistani specimens, thus, making the apical part of tibia, basitarsus, and the most of tarsi black. The pattern in most of the Laotian and Myanmarese specimens have a distinct reduction of the supraclypeal mark in the middle. A specimen from Khong Island (Fig. 6E ) shows more reduction, evidenced by the disruption in the middle of the stripe below the antennal socket, coupled with an additional apical disruption noticed on the clypeus. For the female holotype of Dianthidium riparium from Nan, Thailand, the maculation is more reduced, clearly absent in its supraclypeal area (Fig. 6B ), and thus has a strong disruption on the clypeus.

Individuals from the eastern part of the distribution (China, Laos, Myanmar, and Thailand) have a black background color of the integument with yellow markings (Fig. 8 ). The same is true for the populations in southern India. However, a male from northern India (Hisar) has a reddish brown background color of meso- and metasoma; the ground color of the head is black (face) and reddish brown (vertex). Individuals from Pakistan take an intermediate position, characterized by a scutum with a black background and the abdominal terga with a reddish brown background color (Fig. 8 ). No sexual differences were noted in the distribution of this pattern, i.e., both sexes are paler in Pakistan (4 females, 2 males) and north India (1 male), while the eastern populations are dark in both sexes.

Additionally, specimens from India and Pakistan have a much larger paramedian mark on the scutum, often extending to connect with the anterolateral mark, and generally they display more extensive maculations. The female almost has a fully yellow hindleg, sometimes with the black left on the tarsi and parts of basitarsus. Such individuals with richer yellow maculation are typical for Pakistan. Some females from southern India (including those shown by Kumar et al. 2017: figs 7, 8) have a greater reduction in the yellow clypeal mark, resulting in a complete black stripe in the median area, whereas other specimens come with fully yellow without any black disruption.

For some West Palaearctic Eoanthidium and Rhodanthidium species, Kasparek (2019b, 2020, 2021) reported regional variations in the color pattern and discussed the possibility that the “darker” forms might be a result of adaptation to solar radiation. While in some cases, color variation follows geographical clines, there seems to be reproductive isolation between pale and dark forms in other cases. We observed a clear geographical pattern of color variants in Eo. riparium , but also intermediate forms in Pakistan (see Fig. 8 ), indicating that there is no reproductive isolation.

In addition, Eoanthidium punjabense Gupta & Sharma, 1993 is established here as a new synonym of Eo. riparium . Gupta (1993) noted that these two species are distinguished by the form of the apical margin of the clypeus, the shape of genitalia, color pattern of the integument and body size. While Gupta (1993) solely relied on Pasteels’ (1972) description, the larger material examined by us as well as the examination of Pasteels’ type material enabled a better understanding of the range of variation. The reddish apical margin of the clypeus is crenulated and somewhat irregularly formed. Our material includes one male with two protrusions (Fig. 8D ), very similar to those shown by Gupta (1993: fig. 65). With respect to differences in genital morphology, Gupta (1993) may have been misguided by the incomplete drawings by Pasteels (1972). Body size of Eo. punjabense was found to be within the variability range of Eo. riparium .

Figures

Figure 6. Eoanthidium (Hemidiellum) riparium (Cockerell, 1929). Female holotype of Dianthidium riparium Cockerell, 1929 (syn.) from Thailand (A, B). Male from Thailand (BSRU-AB- 4360) (C, D). Female from Laos (BMNH-ENT- 2017 - 196 (ACQ )) (E), Female from Laos (BSRU-AA- 1224) (F), male from Laos (BSRU-AA- 1236) (G-K), and male from Thailand (BSRU-AB- 4358) (L) H-J male genitalia in dorsal, ventral, and lateral view K male S 8 L apical sterna of male in ventral view. Scale bars: 2 mm (D); 1 mm (A-C, E-G); 0.5 mm (H-L).

Figure 7. Illustration of Eoanthidium (Hemidiellum) riparium (Cockerell, 1929) facial maculation mapped according to their geographic locations (blue boxes indicate Indian-Pakistani morphs, reddish boxes indicate Indochina morphs; a morph marked with asterisk is illustrated based on Wu 1962: fig. 22).

Figure 8. Male of Eoanthidium riparium (Cockerell, 1929) from different regions A-C dorsal view of individuals from South India (Karnakata), Pakistan (Panjab), and North India (Hisar, Haryana) respectively D face of a male Eoanthidium riparium from Pakistan (SEMC 27). Note the change in the ground color from black (A) across reddish brown on terga and black on scutum (B) to entirely reddish brown (C). Also, note the shape of the reddish apical margin of the clypeus (black arrows) which is similar to the drawing of Gupta (1993: fig. 65) for Eo. punjabense.