Subgenus Melanobombus von Dalla Torre, 1880

We associate a total of 186 published formal names with species of the subgenus Melanobombus (including misspellings and infrasubspecific names). Applying the ICZN (1999) rules for an assessment of the status of these names under Article 45.6, just 115 names are considered to be available (unavailable names are not listed here). Below is a list of the 25 species recognised from the integrative analysis together with the major taxonomic and nomenclatural changes since the checklist by Williams (1998).

The subgenera Rufipedibombus and Festivobombus (Richards 1968) were included within the subgenus Melanobombus by Williams et al. (2008), based on evidence from the five genes obtained by Cameron et al. (2007). These groups are recognised here as the rufipes -group of species and the festivus -group of species. Within the remaining species of Melanobombus, two species groups had been recognised by Reinig (1935) and by Williams (1991): the rufofasciatus -group and the lapidarius -group of species. Using the pattern of relationships supported here (Fig. 22), we recognise and label a tanguticus -group, a sichelii -group, and a keriensis -group from our estimate of phylogeny in order to facilitate discussion:

rufipes -group

Bombus eximius Smith, 1852

Bombus rufipes Lepeletier, 1835

festivus -group

Bombus festivus Smith, 1861

rufofasciatus -group

Bombus simillimus Smith, 1852

Bombus miniatus Bingham, 1897

Bombus eurythorax Wang, 1982 stat. rev.

Bombus prshewalskyi Morawitz, 1880 stat. rev.

= Bombus rufocinctus Morawitz, 1880 (non Cresson, 1863) syn. nov.

= Bombus chinensis von Dalla Torre, 1890 (non Morawitz, 1890) syn. nov.

Bombus rufofasciatus Smith, 1852

Bombus richardsiellus (Tkalců, 1968)

Bombus friseanus Skorikov, 1933

Bombus pyrosoma Morawitz, 1890

Bombus formosellus (Frison, 1934)

tanguticus -group

Bombus tanguticus Morawitz, 1887

lapidarius -group

Bombus eriophorus Klug, 1807

= Bombus caucasicus Radoszkowski, 1859

Bombus lapidarius (Linnaeus, 1758)

= Bombus bisiculus Lecocq, Biella, Martinet & Rasmont, 2019 syn. nov.

sichelii -group

Bombus incertus Morawitz, 1881

Bombus semenovianus (Skorikov, 1914)

Bombus sichelii Radoszkowski, 1859

keriensis -group

Bombus ladakhensis Richards, 1928

Bombus alagesianus Reinig, 1930 stat. rev.

Bombus tibeticus Williams sp. nov.

Bombus incertoides Vogt, 1911 stat. rev.

Bombus qilianensis Williams sp. nov.

Bombus keriensis Morawitz, 1887

Bombus separandus Vogt, 1909 stat. rev.

= Bombus lapidarius [subsp.] kohli Vogt, 1909 (non Cockerell, 1906) syn. nov.

= Bombus kozlovi Skorikov, 1910 syn. nov.

= Bombus lapidarius var. tenellus Friese, 1913 syn. nov.

= Bombus tenellus var. alpivagus Richards, 1930 syn. nov.

= Lapidariobombus alagesianus subsp. pamirus Skorikov, 1931 syn. nov.

= Lapidariobombus alagesianus subsp. mongolicus Skorikov, 1931 (non (Friese, 1916) syn. nov. = Bombus keriensis f.g. [subsp.] bucharicus Reinig, 1935 syn. nov.

= Bombus keriensis f.g. [subsp.] richardsi Reinig, 1935 (non Frison, 1930) syn. nov.

= Bombus tenellus subsp. tibetensis S.-F. Wang, 1982 syn. nov.

Key to the species of the subgenus Melanobombus

Future identification of species of the subgenus Melanobombus will be most reliable for specimens from which COI-barcode data are available for comparison of nucleotide differences with the reference data set from this project deposited on www.boldsystems.org, project BBML. Keys using morphological shape, surface sculpturing, and hair-colour-pattern characters follow below, with the most reliable characters placed at the beginning of each couplet. Variation within species necessitates having several terminal couplets for some species. Our results imply that in some cases we should be able to assign most reliably specimens with locality labels to groups or species on the basis of their collection locality alone. All identifications of species from the key or from the figures should be checked against the species’ diagnoses within the accounts of each species.

Diagrams showing the major aspects of variation in the colour-patterns of the dorsal hair are presented in Figs 25–180. These diagrams summarise only the major differences (Williams 2007) rather than the details (Williams 1991: figs 394–439). This is a simplification to aid quantitative comparisons and inevitably requires compromises (Williams 2007). Colour-pattern variation within species is established with reference to particular individuals identified from COI barcodes. Morphology of the male genitalia is illustrated in Figs 181–204.

Key to species for females of the subgenus Melanobombus

1. Hair of the thoracic dorsum entirely black ....................................................................................... 2 – Hair of the thoracic dorsum with some pale hair that is either white or yellow or brown ............... 6

2. Wings nearly clear ............................................................................................................................ 3 – Wings bright yellow or nearly black ................................................................................................ 4

3. Hair of T3 black (Europe) ........................................................ B. lapidarius (Linnaeus, 1758) (part) – Hair of T3 orange-red (China) ................................................... B. pyrosoma Morawitz, 1890 (part) 4. Wings bright yellow with wing veins orange ............................................... B. eximius Smith, 1852 – Wings nearly black with wing veins black ....................................................................................... 5

5. Hair of mid and hind tibiae black and T4–5 red, hind tibia outer surface with many decumbent short branched black hairs (western Himalaya) ....................................... B. simillimus Smith, 1852 (part)

– Hair of mid and hind tibiae orange or black, but if black then T4–5 black, hind tibia outer surface without decumbent short branched black hairs (Sumatra, Java) ............. B. rufipes Lepeletier, 1835

6. Hair of the thoracic dorsum between the wing bases in the centre either white or yellow or brown ........................................................................................................................................................... 7

– Hair of the thoracic dorsum between the wing bases in the centre black, sometimes with some pale hair intermixed, with paler anterior and often posterior bands of pale hair that is either white or yellow ............................................................................................................................................. 10

7. Hair of T5 white ............................................................................................. B. festivus Smith, 1861 – Hair of T5 red ................................................................................................................................... 8

8. Hair of the thoracic dorsum uniformly yellow ........................... B. semenovianus (Skorikov, 1914) – Hair of the thoracic dorsum white .................................................................................................... 9

9. Hair of T2 chocolate brown, side of thorax white, wings dark (western Himalaya) .......................... .............................................................................................................................. B. simillimus (part)

– Hair of T2 black, side of thorax black, wings nearly clear (Caucasus) .............................................. .......................................................................................................... B. eriophorus Klug, 1807 (part)

10. Long hair of the face at the antennal base with an obvious patch dominated by long pale grey or pale yellow hair, which in its centre often has few or no black hairs intermixed ...................................11

– Long hair of the face mostly black, sometimes with a minority of long yellow or grey hair intermixed ....................................................................................................................................... 13

11. Hair of T2 anteriorly brown, T3–5 bright orange-red .................. B. friseanus Skorikov, 1933 (part) – Hair of T2 anteriorly grey or yellow, T3 anterior half at least black, T4–5 orange-red or pale orange or cream .......................................................................................................................................... 12

12. Hair of T2 posteriorly with at least a very narrow fringe of black hair, T3 predominantly black, T4–5 uniformly pale orange-red or pale orange or cream or white ............................................................ ................................................................................................. B. sichelii Radoszkowski, 1859 (part)

– Hair of T2 entirely pale, posteriorly without any black hair, T3 black anteriorly but posteriorly usually with a broad pale fringe, T4–5 orange-red sometimes with paler posterior fringes .......................................................................................... B. keriensis Morawitz, 1887 (part)

13. Hair of the tail entirely orange-red, although sometimes pale, especially in posterior fringes ...... 14 – Hair of the tail with at least some bright white hair posteriorly on T5 ........................................... 30

14. Hair of T3 predominantly red ......................................................................................................... 15 – Hair of T3 predominantly or at least anteriorly broadly black sometimes with a narrow posterior fringe of red or white or cream or yellow ...................................................................................... 18

15. Hair of the pale thoracic bands golden yellow ...................................................... B. friseanus (part) – Hair of the pale thoracic bands grey-white ..................................................................................... 16 16. From mainland China ..................................................................................................................... 17 – From Taiwan ........................................................................................ B. formosellus (Frison, 1934)

17. Hair of face entirely black, thorax anterior and posterior white bands with many black hairs intermixed ............................................................................................................. B. pyrosoma (part)

– Hair of face with short grey hairs intermixed, thorax anterior and posterior white bands with few black hairs intermixed ............................................................................................ B. friseanus (part)

18. Hair of T2 posteriorly with some black .......................................................................................... 19 – Hair of T2 posteriorly entirely either white or cream or yellow .................................................... 20

19. Hair of T1 with at least a few cream or yellow hairs, pale bands of thoracic dorsum either cream or yellow .................................................................................................................. B. lapidarius (part) – Hair of T1 entirely black, pale bands of thoracic dorsum white ......................... B. eriophorus (part)

20. Hindleg basitarsus broad (length 3× greatest breadth) with the distal posterior corner broadly angled (nearly 90°), outer surface with the short hairs golden, hair of the scutellum with few or no black hairs intermixed .............................................................................................................................. 21

– Hindleg basitarsus narrow (length 4× greatest breadth) with the distal posterior corner sharply angled (nearly 45°), outer surface with the short hairs predominantly black, hair of the scutellum often with many black hairs intermixed ............................................. B. tanguticus Morawitz, 1887

21. From Iran westwards to Turkey ...................................................................................................... 22 – From Afghanistan eastwards to Central Asia, Mongolia, Qinghai-Tibetan Plateau ....................... 24

22. Hair of the corbicular fringes black, at most with a few pale tips, pale bands bright white, scutellum anterior margin with few black hairs, leg bases with black hair, T4–5 deep red ................................ ................................................................................................................. B. incertus Morawitz, 1881

– Hair of the distal posterior corbicular fringes often predominantly orange, pale bands either white or cream or yellow, scutellum anterior margin with a narrow band of many black hairs, leg bases with a few pale hairs, T4–5 either red or orange-red ............................................................................. 23

23. Hair of the pale bands bright white, T4–5 red, often the face with a very few white hairs intermixed and T2 posteriorly with a very few black hairs intermixed (Iran) ............................ B. sichelii (part)

– Hair of the pale bands white or cream or yellow, T4–5 orange-red, the face entirely black and T2 posteriorly entirely pale ......................................................................... B. alagesianus Reinig, 1930

24. [NB couplets 24–29 may be reliable only for queens and not for workers] Hair of the pale bands white or grey or cream ................................................................................................................... 25 – Hair of the pale bands light yellow ................................................................................................. 27

25. Hair of the side of the thorax in its lower half with some pale hair and T3 laterally with a few pale hairs, scutellum with a narrow anterior band entirely black but usually covering less than half of the length of the scutellum (Central Asia, Mongolia) .......................................................................... 26

– Hair of the side of the thorax in its lower half entirely black and T3 entirely black, scutellum with the anterior half entirely black (Mongolia) ................................................ B. incertoides Vogt, 1911

26. Hair of face entirely black, T3 more often with a few pale hairs usually only laterally, leg bases more often with many black hairs, T4–5 uniformly orange-red (Central Asia, northwest Qinghai-Tibetan Plateau) ............................................................................................ B. separandus Vogt, 1909 (part)

– Face with at least a very few long pale hairs and/or some short branched pale hairs at the base of the antenna, T3 more often with pale hairs laterally and often posteriorly, leg bases more often predominantly pale with few or no black hairs, T4–5 either uniformly orange-red or posteriorly with distinctly paler fringes (western Himalaya, west Qinghai-Tibetan Plateau) ......... B. keriensis (part)

27. Clypeus in its ventral half with many scattered medium-sized punctures; side of the thorax with yellow hair reaching scarcely more than half of the distance ventrally to the leg bases and the more ventral part entirely black, leg bases entirely black, face entirely black, T3 entirely black (central and southeast Qinghai-Tibetan Plateau) ..................................................................... B. tibeticus sp. nov.

– Clypeus in its ventral half (excluding the depressions adjacent to the labrum) with at most only scattered small punctures; side of the thorax with yellow hair reaching ventrally nearly to the leg bases at least as a very few scattered yellow hairs, leg bases with or without yellow hairs, face black or with a few yellow hairs, T3 either with or without scattered yellow hairs laterally and sometimes posteriorly ....................................................................................................................................... 28

28. Hair of the thoracic dorsum with the black band between the wing bases narrower than the yellow bands and often with yellow hairs intermixed above the wing bases and narrowly near the midline (northeast Qinghai-Tibetan Plateau) ................................................................ B. qilianensis sp. nov.

– Hair of the thoracic dorsum with the black band between the wing bases broader than the yellow bands and without yellow hairs intermixed above the wing bases or narrowly near the midline .. 29

29. Hair of the face usually with at least a very few long pale hairs and/or some short branched pale hairs at the base of the antenna, leg bases with some pale hairs, T3 more often with yellow hairs laterally and sometimes posteriorly, thoracic dorsum pale bands sometimes with a few black hairs intermixed, T4–5 either uniformly orange-red or posteriorly with distinctly paler fringes (western Himalaya, west Qinghai-Tibetan Plateau) ............................................................. B. keriensis (part)

– Hair of the face entirely black, leg bases either with very few yellow hairs or without pale hairs, T3 often without yellow hairs, thoracic dorsum pale bands without black hairs intermixed, T4–5 uniformly orange-red (Mongolia, Russia, northwest Qinghai-Tibetan Plateau) ................................ ............................................................................................................................ B. separandus (part)

30. Hair on the side of the thorax black, or if white in part then the hair on the metasoma is short and T2 is black or anteriorly yellow and the thoracic dorsum has the pale posterior band broad and bright with few black hairs ........................................................................................................................ 31

– Hair on the side of the thorax predominantly either yellow or cream, or if black or white in part then the hair on the metasoma is long and T2 is usually with some white or cream (rarely yellow) and the thoracic dorsum has the pale posterior band often obscured by many black hairs ......................... 33

31. Hair of T3 posteriorly red ............................................................................................................... 32 – Hair of T3 entirely black ................................................................. B. richardsiellus (Tkalců, 1968)

32. Large individuals (body length> 18 mm: queens) with the hair on T2 usually with at least a few scattered yellow hairs intermixed in the anterior lateral corners, small individuals (body length <18 mm: workers) with T2 predominantly yellow with only a very narrow posterior black fringe, thoracic dorsum with anterior and posterior pale bands bright grey with a minority of black hairs intermixed (western Himalaya eastwards to Nepal) ................... B. rufofasciatus Smith, 1852

– Large individuals (body length> 18 mm: queens) with the hair of T2 entirely black, at most with some grey hairs intermixed near the anterior median edge, small individuals (body length <18 mm: workers) with T 2 in the anterior half yellow and in much of the posterior half black, thoracic dorsum with anterior and posterior pale bands dull grey, especially posteriorly often obscure with many black hairs intermixed (Qinghai-Tibetan Plateau, Gansu, Sichuan, Yunnan) ... B. prshewalskyi Morawitz, 1880

33. Hair of the thoracic dorsum with the black band between the wing bases without any pale hairs intermixed next to the wing bases, the hair of the face black ............ B. ladakhensis Richards, 1928

– Hair of the thoracic dorsum with the black band between the wing bases with pale hairs intermixed next to the wing bases, the hair of the face with black and pale hairs intermixed .......................... 34

34. Hair of the thoracic dorsum with the dark band between the wing bases predominantly black with few pale hairs intermixed, the pale bands of the thorax and T1 either brownish-yellow, goldenyellow, or pale greenish-yellow (western Himalaya eastwards to Nepal) .......................................... .................................................................................................................. B. eurythorax Wang, 1982

– Hair of the thoracic dorsum with the dark band between the wing bases with nearly equal numbers of black and pale hairs intermixed, the pale bands of the thorax and T1 either cream or grey-white (Sikkim, Bhutan, Arunachal Pradesh) .................................................... B. miniatus Bingham, 1897

Key to species for males of the subgenus Melanobombus

(males of B. tanguticus remain unknown, see the species account for further detail)

1. Hair of the thoracic dorsum uniformly either black or orange-brown or black with short grey hairs intermixed; genitalia with penis-valve head with the recurved inner hook nearly as broad as long .. ........................................................................................................................................................... 2

– Hair of the thoracic dorsum in part either yellow or white, often with a band of black between the wing bases; genitalia with penis-valve head with the recurved inner hook either much longer than broad or rarely the recurved part fused to the shaft (B. ladakhensis) ............................................... 4

2. Hair of the thoracic dorsum uniformly orange-brown; genitalia with penis-valve head with outer distal outer flange narrower than the length of the recurved inner hook ....... B. festivus Smith, 1861

– Hair of the thoracic dorsum either uniformly black or black with short grey hairs intermixed; genitalia with penis-valve head with distal outer flange broader than the length of the recurved inner hook .................................................................................................................................................. 3

3. Wings bright yellow with wing veins orange; long hair of the face with short pale brown hair intermixed ..................................................................................................... B. eximius Smith, 1852

– Wings nearly black with wing veins black; hair of the face entirely black ........................................ .................................................................................................................. B. rufipes Lepeletier, 1835

4. Genitalia with gonostylus posteriorly reduced and transverse, <0.5× as long as broad, the volsella projecting beyond the gonostylus by> 2 × as long as gonostylus (Asian mountains) ..................... 5

– Genitalia with gonostylus rounded and disc-like, nearly 1× as long as broad, the volsella projecting beyond the gonostylus by <1 × as long as gonostylus (widespread) ............................................. 13

5. Hair of the thoracic dorsum in part white, not yellow ...................................................................... 6 – Hair of the thoracic dorsum in part yellow, not white ...................................................................... 8

6. Hair of the thoracic dorsum entirely white ............................................... B. simillimus Smith, 1852 – Hair of the thoracic dorsum with a band of black at least intermixed between the wing bases ....... 7

7. Hair of T2 bright yellow with only a very narrow band with few black hairs along the posterior margin (western Himalaya east to Nepal) ............................................ B. rufofasciatus Smith, 1852

– Hair of T2 dull yellow with either at least a few black hairs intermixed or often with many black hairs intermixed and with a broad black band in the posterior quarter that often extends medially towards the anterior (eastern Himalaya from Arunachal Pradesh to the interior of the QinghaiTibetan Plateau, Gansu, Sichuan, Yunnan) ..................................... B. prshewalskyi Morawitz, 1880

8. Genitalia with gonostylus with the posterior interior process reduced to a single narrow spine ..... 9 – Genitalia with gonostylus with the posterior interior process broad with two distal corners ..........11

9. Gonostylus inner basal process narrow with the distal angle <45°; hair of T3 sometimes partly black but with at least the posterior margin fringed with yellow ............................................................. 10

– Gonostylus inner basal process broad with the distal angle nearly 90°; hair of T3 predominantly black ................................................................................................ B. richardsiellus (Tkalců, 1968)

10. Hair of T3–5 orange-red with at least a narrow band of yellow along the posterior margin, sometimes entirely yellow (western Himalaya east to Nepal) ................................... B. eurythorax Wang, 1982

– Hair of T3–5 orange-red sometimes with a few black hairs along the posterior margin (Sikkim, Bhutan, Tibet, Arunachal Pradesh) ......................................................... B. miniatus Bingham, 1897

11. Genitalia with gonostylus with the posterior interior process with the two inner corners projecting with the same length; hair of T2 yellow with very few black hairs (North China) ............................ .............................................................................................................. B. pyrosoma Morawitz, 1890

– Genitalia with gonostylus with the posterior interior process with the dorsal inner corner projecting inwards further than the ventral inner corner; hair of T2 yellow with many black hairs posteriorly. ......................................................................................................................................................... 12

12. Hair of T4 orange-red with few or no black hairs (Xizang, Qinghai, Yunnan, Sichuan, Guizhou) .... ................................................................................................................ B. friseanus Skorikov, 1933

– Hair of T4 orange-red with many black hairs especially laterally (Taiwan) ...................................... .............................................................................................................. B. formosellus (Frison, 1934)

13. Genitalia with penis-valve head with the recurved inner hook extensively fused for 0.75 of its length with the adjacent penis-valve shaft; hair of T6–7 orange-red at the base and white distally ............. ............................................................................................................ B. ladakhensis Richards, 1928

– Genitalia with penis-valve head with the recurved inner hook not fused for ± 0.5 of its length with the adjacent penis-valve shaft; hair of T6–7 orange-red at the base and usually orange distally ... 14

14. Hair of the thoracic dorsum in part either white or cream ............................................................. 15 – Hair of the thoracic dorsum either in part yellow or entirely black ............................................... 19

15. Eyes distinctly enlarged relative to eyes of the females; hair of the face, ventral half of the side of the thorax, and anterior half of the scutellum black with few white hairs intermixed (Mongolia) .... .................................................................................................................... B. incertoides Vogt, 1911

– Eyes similar in relative size to eyes of the females; hair of the face, ventral half of the side of the thorax, and anterior half of the scutellum either white or with few black hairs intermixed ........... 16

16. Hair of T2 posteriorly without a narrow fringe of black hairs and entirely pale ............................ 17 – Hair of T2 posteriorly with a narrow fringe of black hairs ..... B. sichelii Radoszkowski, 1859 (part)

17. From Afghanistan or eastwards to Mongolia .................................. B. separandus Vogt, 1909 (part) – From Iran or westwards to Turkey ................................................................................................. 18

18. Hair of the pale bands white, black band between the wing bases narrower than the anterior white band, scutellum anterior margin with few black hairs, T4–5 red ........... B. incertus Morawitz, 1881

– Hair of the pale bands either white or cream, black band between the wing bases broader than the anterior pale band, scutellum anterior margin with a narrow band of many black hairs, T4–5 orangered ................................................................................................ B. alagesianus Reinig, 1930 (part)

19. Eyes distinctly enlarged relative to eyes of the females; hair of the face predominantly black with a few yellow hairs intermixed ....................................................... B. semenovianus (Skorikov, 1914) – Eyes similar in relative size to eyes of the females; hair of the face predominantly yellow .......... 20

20. Hair of T2 usually predominantly black ......................................................................................... 21 – Hair of T2 predominantly yellow ................................................................................................... 22

21. Hair of the thoracic dorsum either extensively or entirely black, hair of T1 often yellow (Europe, Turkey) ............................................................................................... B. lapidarius (Linnaeus, 1758)

– Hair of the thoracic dorsum either entirely yellow or if there is a narrow black band between the wing bases then T1 is entirely black (Turkey, Caucasus) .......................... B. eriophorus Klug, 1807

22. Hair of T2 posteriorly with a broad fringe of black hairs ......................................... B. sichelii (part) – Hair of T2 posteriorly either entirely yellow or with a very few black hairs posteriorly restricted to the middle ....................................................................................................................................... 23

23. From Iran or westwards .................................................................................... B. alagesianus (part) – From Afghanistan or eastwards ...................................................................................................... 24

24. From Mongolia or Russia .................................................................................. B. separandus (part) – From the Qinghai-Tibetan Plateau .................................................................................................. 25

25. Hair of T3 entirely black ...................................................................................... B. tibeticus sp. nov. – Hair of T3 black with yellow hairs laterally ................................................................................... 26

26. Hair of T2 entirely yellow (eastern Qinghai-Tibetan Plateau) ........................ B. qilianensis sp. nov. – Hair of T2 yellow with a very few black hairs posteriorly in the middle (western Qinghai-Tibetan Plateau) .................................................................................................. B. keriensis Morawitz, 1887

Review of the species

Accounts of the 25 species accepted after integrated assessment follow below. Square brackets [Bombus xus] are used to indicate transliterations, translations, and interpretations.