taxonID	type	description	language	source
AC4D691FFFB25E16FF685FF47141F976.taxon	description	(Figs. 1, 15 ‒ 21, 129)	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFB25E16FF685FF47141F976.taxon	description	Note 1 (rufescens). The type-locality citation appears false because it refers to a location on the western edge of Paris, where this species is very unlikely to have occurred. The explanation is not pursued further here because it is unlikely to affect the valid name for this or any other Alpinobombus species. Taxonomy and variation. A species coalescent in the COI gene (Fig. 9) and divergence in the PEPCK gene characterising B. alpinus have been demonstrated by Williams et al. (2015). Morphometric differences between B. alpinus and B. pyrrhopygus (as B. polaris) have been demonstrated graphically by Løken (1973) and Pekkarinen (1979). Variation in colour pattern is primarily in the extent of yellow hairs on the dorsum of the thorax. Extensive yellow hair is rare in females (Fig. 16) but more frequent in males (Fig. 18). Variation in COI sequences between the samples from the Alps and samples from Scandinavia shows divergence at only one base position (Figs. 9, 14).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFB25E16FF685FF47141F976.taxon	materials_examined	Material examined. 15 queens 54 workers 19 males (plus 28 females with caste undetermined), from France, Switzerland, Austria, Italy, Romania, Norway, Sweden, and Russia (Fig. 15: FO INHS NHMUK PW ZISP), with 15 specimens barcoded. Habitat and distribution. Flower-rich arctic / alpine tundra in the Old World from the far north of Scandinavia, east only to the Kola Peninsula, extending southwards into the subarctic region in the alpine zone of the southern Scandinavian mountains, as well as disjunctly in the alpine zone into the temperate region of the Alps and western Carpathian mountains. Regional distribution maps (Skorikov 1931; Pittioni 1942; Løken 1973; Pekkarinen et al. 1981; Rasmont & Iserbyt 2012; Cederberg et al. 2013 a; Ødegaard et al. 2015; Rasmont et al. 2015).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFB25E16FF685FF47141F976.taxon	description	Food plants. (Richards 1931; Løken 1973; Mossberg & Cederberg 2012) Behaviour. (Løken 1973; Svensson & Lundberg 1977) Conservation status. This species has been assessed for Red List threat status using IUCN criteria (2001). Cederberg et al. (2013 a) assessed the Red List status of this species as ‘ Vulnerable’ because its known area of occupancy (AOO) is small (1,288 km ²) and because it is experiencing a continuing decline due to climate warming. Subsequently, Rasmont et al. (2015) have assessed the risk from climate change to this species as ‘ very high climate change risk’ (HHR), projecting that it will be on the verge of extinction by the year 2100.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFB25E1BFF685951704FFC48.taxon	description	(Figs. 2, 22 ‒ 38, 130)	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFB25E1BFF685951704FFC48.taxon	description	Note 1 (pyrrhopygus). Friese (1902) described the taxon B. kirbyellus ssp. pyrrhopygus giving characters of colour pattern, and the type locality as ‘ Nowaja Semlja’ (= Novaya Zemlya) from material collected by G. Jacobson (Friese 1905). We now understand that this island has just two species: B. hyperboreus and the Old World sister-species to B. polaris, and does not have the true B. kirbiellus (the correct original spelling of B. kirbyellus). Friese (1905) on page 509 lists males and females of his ‘ B. kirbyellus - pyropygus ’ collected from Novaya Zemlya on August 2 and 4 of 1896. On page 515 he lists a further female collected by G. Jacobson from Novaya Zemlya on July 23 1896. Therefore it is likely that multiple syntypes existed. Unfortunately at no point did he state an intention to change the spelling of the name, and neither did he include both spellings of his pyrrhopygus and pyropygus in the same publication, so that the latter form has to be treated as an incorrect subsequent spelling (ICZN 1999: Article 33.3). Friese (1905) also includes the taxon pleuralis Nylander (a misidentification of a North American species of the subgenus Pyrobombus, = B. flavifrons Cresson, type examined by PW, but interpreted by Friese as a taxon of the subgenus Alpinobombus) from Novaya Zemlya as a subspecies of B. kirbiellus. Friese’s interpretation of pleuralis presumably also represents the Old World sister-species to B. polaris. This is not the same species as the true B. kirbiellus, which we believe is absent from the island. Skorikov (1914) distinguished his interpretation of B. pleuralis Nylander (as a species of the subgenus Alpinobombus) from B. kirbiellus by the shape of the head. On page 124 he refers pyrrhopygus Friese to his interpretation of the species B. pleuralis rather than to B. kirbiellus, from which he reiterates that pyrrhopygus Friese differs in characters signifying a different species. Richards (1931) places B. kirbyellus ssp. pyrrhopygus Friese in synonymy with his interpretation of B. arcticus Kirby. Taking this information together, we consider that the oldest available name for the Old World sister-species to the New World B. polaris is likely to be B. pyrrhopygus Friese. An examination of the type material is needed. Note 2 (pyrrhopygus). It is likely that multiple syntypes existed (note 1). The MNHU collection contains a small queen (# 4707) that agrees with the original description (with red hair on T 4 ‒ 6 and with some yellow hair) and carries the labels: (1) white, printed (Cryrillic) ‘ [Mal. Karmakul, / Novaya Zemlya. / Yakobson] 23. VII. 96 ’; (2) white, handwritten in pen ‘ B. kirbyellus / pyropygus / [female] 1900 Friese det. / Fr. ’; (3) white, printed label ‘ Zool. Mus. / Berlin’; (4) white, printed ‘ Alpinobombus / AL # 4707. det. PHW’; (5) red, printed ‘ LECTOTYPE [female] / Bombus / kirbyellus ssp. / pyrrhopygus / Friese, 1902 / det. PH Williams 2015 ’; (6) white, printed ‘ [female] Bombus / (Alpinobombus) / pyrrhopygus / det. PH Williams 2015 ’. This specimen agrees with the collection data for 23 July 1896 referred to by Friese (1905: 515) in connection with the description of this taxon. The specimen lacks most of the right antennal flagellum and has some Anthrenus damage to the left cheek. It is designated here as lectotype in order to reduce uncertainty in the identity and application of the name. Note 3 (pyropygus). Friese’s (1902) original spelling of this name was ‘ pyrrhopygus ’. This is a compound, combining pyrros (meaning ‘ flame-red’) with pygos (meaning ‘ bottomed’), presumably relating to the red tail of this bee, but with a common incorrect Latinization that includes an ‘ h’ (M. A. Alonso-Zarazaga, in litt.). Friese (1905) may then have sought to emend the spelling to ‘ pyropygus ’. However, Friese (1905) did not show the clear evidence for a demonstrably intentional change in the spelling from pyrrhopygus to pyropygus that is required for an emendation (ICZN 1999: Article 33.2.1), so the spelling pyropygus remains an incorrect subsequent spelling and an unavailable name (Article 33.3). In the last fifty years, both names occur only in lists of synonyms or in notes on colour variation. Note 4 (friesei). The name friesei was published by Skorikov (1908) for a taxon as a variety alongside other taxa given subspecific rank, so that infrasubspecific rank is clearly intended for the taxon friesei (ICZN 1999: Article 45.6.1). Subsequent references to this taxon before 1985 (e. g. Richards 1931; Skorikov 1937; Løken 1973) make no change to this status (ICZN 1999: Article 45.6.4.1), although they do refer the taxon friesei to the species now named here as B. pyrrhopygus. Note 5 (cinctus). Friese specified that three syntype males existed. The MNHU collection contains a male (# 4711) that agrees with the original description (like pyrrhopygus [hair of T 4 ‒ 6 red] but hair of the face with yel- low, T 3 posterior margin yellow, T 4 anterior black) and carries the labels: (1) white, printed (Cryrillic) ‘ [Mal. Karmakul, / Novaya Zemlya. / Yakobson] 23. VII. 96 ’; (2) white, handwritten in pen ‘ B. kirbyellus / v. cinctus / [male] 1910 Friese det. / Fr. ’; (3) dark red, printed label ‘ Type’; (4) white, printed label ‘ Zool. Mus. / Berlin’; (5) white, printed ‘ Alpinobombus / AL # 4711. det. PHW’; (6) red, printed ‘ LECTOTYPE [male] / Bombus / kirbyellus var. / cinctus / Friese, 1911 / det. PH Williams 2015 ’; (7) white, printed ‘ [male] Bombus / (Alpinobombus) / pyrrhopygus / det. PH Williams 2015 ’. The specimen lacks part of the right antennal flagellum. It is designated here as lectotype in order to reduce uncertainty in the identity and application of the name. Note 6 (cinctellus). Friese specified that two syntype males existed. The MNHU collection contains a male (# 4712) that agrees with the original description (like pleuralis [hair of T 4 ‒ 6 black] but hair of T 3 posterior mar- gin yellow) and carries the labels: (1) white, printed (Cryrillic) ‘ [Mal. Karmakul, / Novaya Zemlya. / Yakobson] 23. VII. 96 ’; (2) white, handwritten in pen ‘ B. kirbyellus / v. cinctellus / [male] 1910 Friese det. / Fr. ’; (3) white, printed label ‘ Zool. Mus. / Berlin’; (4) white, printed ‘ Alpinobombus / AL # 4712. det. PHW’; (5) red, printed ‘ LEC- TOTYPE [male] / Bombus / kirbyellus var. / cinctellus / Friese, 1911 / det. PH Williams 2015 ’; (6) white, printed ‘ [male] Bombus / (Alpinobombus) / pyrrhopygus / det. PH Williams 2015 ’. The specimen lacks the left mid leg. It is designated here as lectotype in order to reduce uncertainty in the identity and application of the name. Note 7 (semljaensis). Friese specified that five syntypes existed, although he lists them as workers. The MNHU collection contains a male (# 4713) that agrees with the original description (hair of T 1 ‒ 2 yellow, T 3 ‒ 4 black, T 5 ‒ 6 red) and carries the labels: (1) white, part handwritten in pen ‘ Novaj Semlja Ökland / Pomorskye bügt / 27 aug. No. 286 ’; (2) white, handwritten in pen ‘ B. kirbyellus / v. semljaënsis / [male] 1922 Friese det. / Fr. ’; (3) dark red, printed label ‘ Type’; (4) white, printed label ‘ Zool. Mus. / Berlin’; (5) white, printed ‘ Alpinobombus / AL # 4713. det. PHW’; (6) red, printed ‘ LECTOTYPE [male] / Bombus / kirbyellus var. / semljaensis / Friese, 1923 / det. PH Williams 2015 ’; (7) white, printed ‘ [male] Bombus / (Alpinobombus) / pyrrhopygus / det. PH Williams 2015 ’. Although this is a male rather than a worker, it matches the specimen number (‘ Nr. 286 ’) as well as the date and site data in the original description. It also carries the Friese type and ‘ semljaënsis’ determination labels. Misprinting of its sex in the paper is likely, so that this is believed to be a syntype. The specimen lacks most of the right antennal flagellum has substantial Anthrenus damage, especially to the head. It is designated here as lectotype in order to reduce uncertainty in the identity and application of the name. Taxonomy and variation. Bombus pyrrhopygus has long been considered part of B. polaris but has recently been recognized as separate from evidence of a species coalescent in the COI gene (Williams et al. 2015; Fig. 9). Morphometric distinction between B. pyrrhopygus (under the name B. polaris) and B. alpinus has been demonstrated graphically by Løken (1973) and Pekkarinen (1979). Bombus pyrrhopygus is vicariant with B. polaris across the Bering Strait (Figs. 22, 39). Variation in the colour pattern has been analysed previously (Williams et al. 2015). Variation in the colour pattern is most obvious between the ‘ unbanded’ pattern without yellow bands on the thorax or on T 1 ‒ 2 (the taxon diabolicus) in Scandinavia and Murmansk (Figs. 27 ‒ 31, 37 ‒ 38) and the yellow-banded pattern further east in Rus- sia, beyond Beloye More (the White Sea) (Figs. 23 ‒ 24, 32 ‒ 34). For the weakly banded or unbanded individuals, the hair of T 2 ‒ 4 shows variation in the replacement of orange with black progressively from T 2 ‒ 4 (Figs. 25 ‒ 31, 35 ‒ 38). Otherwise the principal variation in this species is in whether the hair of T 4 ‒ 5 is predominantly orange (the taxon pyrrhopygus Figs. 23, 32) or predominantly black (the taxon cinctellus Figs. 24, 33). There may be some variation in the relative frequency of the two patterns with latitude (Williams et al. 2015). Despite the apparent strong difference in the colour patterns, individuals with both the banded and the unbanded colour patterns share some of the same alleles (Fig. 14). Nonetheless, more detailed study of variation in the COI gene within B. pyrrhopygus across Russia is needed.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFB25E1BFF685951704FFC48.taxon	materials_examined	Material examined. 61 queens 39 workers 102 males (plus 289 females with caste undetermined), from Norway, Sweden, Finland, and Russia (Fig. 22: AB FO MB MNHU NHMUK PW SC ZISP), with 37 specimens barcoded. Habitat and distribution. Flower-rich arctic / alpine tundra in the Old World from the far north of Scandinavia, Taymyr, Novaya Zemlya and Wrangel Island, extending southwards into the subarctic region in the alpine zone of the Scandinavian, Kamchatkan, and Magadan mountains. One record for a Russian female in the ZISP collection from the Stanovoy range (# 1332) needs confirmation because the habitat appears climatically unsuitable (cf. the Maxent climatic suitability model in Fig. 7). Regional distribution maps (Løken 1973; Pekkarinen et al. 1981; Rasmont & Iserbyt 2012; Ødegaard et al. 2015; Rasmont et al. 2015).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFB25E1BFF685951704FFC48.taxon	description	Food plants. (Mossberg & Cederberg 2012) Behaviour. (Løken 1973; Svensson & Lundberg 1977) Conservation status. This species has been assessed in part for Red List threat status using IUCN criteria (2001). Rasmont et al. (2014) assessed the Red List status of this species (under the name B. polaris) as ‘ Vulnerable’ in Europe because its known area of occupancy (AOO) for Europe is small (<700 km ²) and because it has experienced a strong and continuing decline due to climate warming. Subsequently, Rasmont et al. (2015) have assessed the risk from climate change to this species (under the name B. polaris) in Europe as ‘ extremely high climate change risk’ (HHHR), projecting that it will have no chance of persistence in Europe to survive the expected warming.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFBF5E1EFF685A707683FAD4.taxon	description	(Figs. 3, 39 ‒ 58, 131, 140, 142, 147)	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFBF5E1EFF685A707683FAD4.taxon	description	[Alpinibombus kincaidi (Cockerell); Skorikov 1937: 58, incorrect subsequent spelling.] Note 1 (arcticus). That more than one syntype was seen by Kirby is indicated by the description of both sexes and by a broad region of type localities. The NHMUK collection contains a queen (# 3857) that has been regarded as the primary type of this taxon (e. g. Milliron 1960: 89; Løken 1973: 101; see also Richards 1931: 11). However, none of these authors explicitly recognized the description of a syntype series in the original William Kirby publication and then selected a single individual as the lectotype, so these uses of the term ‘ type’ do not constitute a valid lectotype designation (ICZN 1999: Article 74.5). This NHMUK specimen carries the labels: (1) white, ‘ B. arcticus ’ in handwriting that appears to form much more rounded letters than did Kirby (see below); (2) white round, handwritten label ‘ 40 / 4 – 2 / 628 ’; (3) white, handwritten ‘ Bombus / arcticus / TYPE Kirby. ’; (4) red-edged, printed ‘ Type’; (5) white, printed ‘ B. M. TYPE / HYM. / 17 B. 1043. ’; (6) red-edged, printed ‘ Holo- / type’; (7) green, printed ‘ Alpinobombus / AL # 3857. det. PHW’. The NHMUK accession number on the second label refers in the NHMUK accessions register to a purchase ‘ Bought at Mr Children’s sale’ in 1840. This is presumably a reference to John Children, who became Keeper of Zoology at the British Museum, retiring in 1840. It is possible that Children may have acquired the specimen from Kirby through his association with the BM, so that this specimen could be a syntype. Milliron (1973: 100) suggested that the specimen was labelled as type by Frederick Smith. However, this NHMUK specimen does not agree with the original Kirby description in that: (1) the hair of metasomal T 4 ‒ 6 is not entirely black but has a lot of brownish grey hair; (2) it does not have ‘ Some black hairs at the base of the last yellow segment of this part of the body’ (for this specimen the last yellow segment is metasomal T 2); and (3) its body length (17 mm) is substantially shorter than the description of 11 lines (23 mm). While this specimen may be a syntype, at present its status remains uncertain. In contrast, the NHMUK collection contains another female specimen (# 285) that agrees more closely with the original description in having the hair of metasomal T 4 ‒ 6 black. It agrees particularly closely in having ‘ Some black hairs at the base of the last yellow segment of this part of the body’ (for this specimen, metasomal T 3) and in its large body length, which matches the description of 11 lines (23 mm). This specimen has labels: (1) white, ‘ Bombus / arcticus K / Melvilles I. / Sabine ’ in handwriting closely similar to examples of Kirby’s handwriting in the NHMUK Kirby collection (Edward Sabine held the rank of Astronomer on HMS Hecla of William Parry’s expedition to seek the Northwest Passage and was the author of the sections in the account on mammals, birds, fish, and insects); (2) green, printed ‘ Alpinobombus / AL # 285. det. PHW’; (3) red, printed ‘ LECTOTYPE [female] / Bombus / arcticus / Kirby, 1824 / det. PH Williams 2014 ’; (4) white, printed ‘ [female] Bombus / (Alpinobombus) / polaris / det. PH Williams 2014 ’. This specimen is regarded here as one of Kirby’s syntypes because it matches the original description in individual detail and carries a Melville Island label in what appears to be early nineteenth century handwriting, closely similar to that of Kirby, along with the name of Sabine, who was part of the Parry expedition. The specimen has been damaged by physical compression, by Anthrenus attack, has droplets of glue especially on its head, and is now mounted on a strip of board. It is designated here as lectotype in order to reduce uncertainty in the identity and application of the name, which is interpreted as remaining applied to the same species. Note 2 (arcticus). The glossary of the ICZN (1999: 111) states that nomina oblita (e. g. Bombus arcticus (Quensel )) remain available names. Therefore Bombus arcticus (Quensel) remains a senior homonym for Bombus arcticus Kirby. Note 3 (polaris). Only a pair of male and female syntypes were described by John Curtis. The NHMUK collection contains a queen that has been regarded as the primary type of this taxon (e. g. Milliron 1960: 95; Løken 1973: 101). It agrees with the original description (with extensive orange-yellow hair on metasomal T 3 ‒ 5) and car- ries the labels: (1) white, handwritten ‘ Bombus / polaris. Curt. Type. from Curtis. ’; (2) white, part handwritten ‘ type F. Sm. Coll. / 79.22 ’; (3) printed white with a red border ‘ Type’; (4) white, printed ‘ B. M. TYPE / HYM. / 17. B. 1054 ’; (5) printed white with a red border ‘ Holo / type’; (6) green, printed ‘ Alpinobombus / AL # 3856. det. PHW’; (7) red, printed ‘ LECTOTYPE [female] / Bombus / polaris / Curtis, 1835 / det. PH Williams 2014 ’; (8) white, printed ‘ [female] Bombus / (Alpinobombus) / polaris / det. PH Williams 2014 ’. The specimen lacks only the antennae. It is designated here as lectotype in order to reduce uncertainty in the identity and application of the name. Note 4 (polaris). Because Bombus arcticus Kirby is a junior homonym (see note 2 above), it cannot be used as the valid name for this species (ICZN 1999: Article 52.2), which must take the next oldest available name, Bombus polaris Curtis. Note 5 (groenlandicus). Smith’s description of Bombus groenlandicus states: ‘ Abdomen, the two basal segments covered with long yellow pubescence, the apical ones with black’. The specimen in the NHMUK collection labelled as the holotype (# 4740) has dull orange hair intermixed posteriorly on metasomal tergum 4 and more extensively on tergum 5, although the orange is less obvious than on some specimens. This discrepancy with Smith’s description is not pursued here because it is unlikely to affect the valid name of the species. Note 6 (kincaidii). Cockerell listed 4 queens, 1 worker, and 2 males as syntypes in the original description, without specifying a holotype. The NMNH collection contains a queen (# 4407) that has been regarded as the primary type of this taxon (e. g. Franklin 1913: 295). However, Franklin did not explicitly select a single individual as the lectotype, so this use of the term ‘ type’ does not constitute a valid lectotype designation (ICZN 1999: Article 74.5). The NMNH queen that has been regarded as the primary type of this taxon (Franklin 1913: 295) agrees with the original description (with extensive yellow hair on metasomal T 1 ‒ 3, black hair on T 4 ‒ 6) and carries the labels: (1) white, handwritten in black ink ‘ Pribilof Is / St Paul’; (2) white, handwritten in pencil ‘ 8 1 / 97 ’; (3) white, handwritten in pencil ‘ Lathyrus’; (4) white, handwritten in black ink ‘ Bombus / Kincaidii / Ckll TYPE. ’; (5) red, part printed ‘ Type / No. 5179 / U. S. N. M. ’; (6) yellow, printed ‘ USNM ENT / 00534360 / [barcode] ’; (7) green, printed ‘ Alpinobombus / AL # 4407. det. PHW’; (8) red, printed ‘ LECTOTYPE [female] / Bombus / kincaidii / Cockerell, 1898 / det. PH Williams 2014 ’; (9) white, printed ‘ [female] Bombus / (Alpinobombus) / polaris / det. PH Williams 2014 ’. The specimen lacks the right antennal flagellum and part of the right hind tarsus. It is designated here as lectotype in order to reduce uncertainty in the identity and application of the name. Taxonomy and variation. Bombus polaris has long been considered to include B. pyrrhopygus but has recently been recognized as separate based on evidence of a species coalescent in the COI gene (Williams et al. 2015; Fig. 9). Bombus polaris is vicariant with B. pyrrhopygus across the Bering Strait (Figs. 22, 39). Variation in the colour pattern has been illustrated and analysed previously (Williams et al. 2014; Williams et al. 2015). The ‘ unbanded’ colour pattern without (or with much reduced) yellow bands on the thorax and T 1 ‒ 2 (Figs. 51, 58) is rare and known to us only from the Northwest Territories (Daring Lake: # 19) and Nunavut (Churchill: # 29). Individuals from the Bering Sea islands are especially pale (Fig. 41). Otherwise the principal variation in this species is in whether T 4 ‒ 5 are predominantly orange (Figs. 40 ‒ 45, 51 ‒ 55, 57 ‒ 58) or predominantly black (Figs. 46 ‒ 50, 56). Individuals with both the banded and the unbanded colour patterns and both the ‘ orange-tailed’ and ‘ blacktailed’ colour patterns share some of the same alleles, although there may be some variation in the relative frequency of the two patterns with latitude (Williams et al. 2015).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFBF5E1EFF685A707683FAD4.taxon	materials_examined	Material examined. 452 queens 232 workers 152 males (plus 54 individuals with sex / caste undetermined), from USA, Canada, and Greenland (Fig. 39: AMNH BBSL BP CNC CR EMEC INHS KM NHMUK MNHU NMNH PCYU PR PW RBCM ROM RSM SC SEMC UAM UCRC WRME YPM ZISP), with 53 specimens COI barcoded. Habitat and distribution. Flower-rich arctic / alpine tundra in the New World including Greenland, north to Ellesmere Island and the north of Greenland, extending southwards into the subarctic region in the St Paul Islands and Aleutian Islands, and in the alpine zone of the Alaskan and Yukon mountains. Regional distribution maps (Milliron 1973; Richards 1973; Laverty & Harder 1988; Williams et al. 2014).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFBF5E1EFF685A707683FAD4.taxon	description	Food plants. (Richards 1931; Milliron & Oliver 1966; Milliron 1973; Richards 1973; Pape 1983; Williams et al. 2014) Behaviour. (Milliron & Oliver 1966; Richards 1973; Pape 1983) Conservation status. This species has not yet been fully assessed for Red List threat status using IUCN criteria (2001). Hatfield et al. (2016 d) have listed B. polaris as ‘ Data deficient’.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFBA5E21FF685BC47176FB23.taxon	description	(Figs. 4, 59 ‒ 76, 132) B. <ombus> balteatus Dahlbom 1832: 36, type-locality citation ‘ Lapponia Tornensi ad Enontekis’. Neotype queen (# 5011) by designation of Nilsson 2008: 3, ZMU examined PW, ‘ Sweden, Lappland’ (Norrbotten, Sweden). Proposed nomen protectum. Notes 1, 2. B. <ombus> nivalis Dahlbom 1832: 40, type-locality citation ‘ Alpium Tornensium’. Lectotype queen by designation of Milliron 1960: 94, ZIL not seen, ‘ Torneåträsk’ (Norrbotten, Sweden). Synonymised with Bombus balteatus Dahlbom by Thomson 1872: 35). Proposed nomen oblitum. Note 2. B. <ombus> tricolor Dahlbom 1832: 41, type-locality citation ‘ Karesuando Lapponiae Tornensis’ (Norrbotten, Sweden). Holotype male by monotypy (Ander 1967: 185), ZIL not seen. Synonymised with Bombus balteatus Dahlbom by Thomson 1872: 35). Proposed nomen oblitum. Note 2. [Bombus batteatus Dahlbom; Etzel 1859: 144, incorrect subsequent spelling.]	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFBA5E21FF685BC47176FB23.taxon	description	B. <ombus> kirbyellus var. similis Friese 1911 c: 684 (not of Fabricius 1804: 351, = Centris similis (Fabricius )), replacement name for tristis Friese (1902: 495).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFBA5E21FF685BC47176FB23.taxon	description	[B. <ombus> balteatus balteatus m. balteatus f. pleurotricolor, f. subtristis, f. pleurobalteatus, f. alexanderioides, f. analinigrescens Pittioni 1942: 216, infrasubspecific.] [B. <ombus> balteatus balteatus m. nivalis f. parvoanalis, f. pleuroparvoanalis, f. pleuronivalis Pittioni 1942: 216, infrasubspecific.] Note 1 (balteatus). Milliron (1960: 89) designated as lectotype a worker, although Ander (1967: 186) argued that this was not an original syntype, so that the designation is invalid. Nilsson (2008: 3) described the unsuccessful search for an original syntype. In its absence, he designated as neotype a queen that agrees with the usual interpretation of the species (e. g. Løken 1973). Note 2 (balteatus, nivalis, tricolor). Richards (1931) believed B. balteatus Dahlbom and B. nivalis Dahlbom to be conspecific and selected the name B. balteatus Dahlbom to have precedence because it was published on an earlier page (page priority is not a mandatory part of the Code). However, Thomson (1872: 35) had already chosen the name B. nivalis Dahlbom in precedence to both B. balteatus Dahlbom and B. tricolor Dahlbom. Following the Principle of the First Reviser (ICZN 1999: Article 24.2.2), Thomson’s action should now stand, so that the valid name for this species would be B. nivalis Dahlbom. However, we propose that in this case it is appropriate to maintain the prevailing usage of the name B. balteatus Dahlbom (ICZN 1999: Article 23.9.2), because as far as we are aware neither the name B. nivalis Dahlbom nor the name B. tricolor Dahlbom has been used in subsequent publications as the valid name for this species after 1899 (ICZN 1999: Article 23.9.1.1), except for a few early references to this species under the name B. nivalis (Lie-Pettersen 1901, 1907; Bengtsson 1908). In contrast, the name B. balteatus Dahlbom has been the name in common use for this species in more than 25 works, published by at least 10 authors in the preceding 50 years (ICZN 1999: Article 23.9.1.2) (since 1968: e. g. Løken 1973; Plowright & Stephen 1973; Sakagami 1976; Svensson & Lundberg 1977; Pekkarinen 1979; Pekkarinen et al. 1981; Reinig 1981; Rasmont 1983 a; Ito 1985; Ito & Sakagami 1985; Pekkarinen & Teräs 1993; Chen & Wang 1997; Williams 1998; Koulianos 1999; Pedersen 2002; Hines et al. 2006; Cameron et al. 2007; Holmström 2007; Nilsson 2008; Gjershaug 2009; Goulson 2010; Ebmer 2011; Berezin & Tkacheva 2012; Mossberg & Cederberg 2012; Rasmont & Iserbyt 2012; Potapov et al. 2014; Ødegaard et al. 2015; Rasmont et al. 2015). If challenged, the matter should be referred to the Commission for a ruling under its plenary power (ICZN 1999: Article 81). While the case were under consideration, use of the name B. balteatus Dahlbom would need to be maintained (ICZN 1999: Article 82). Bombus balteatus Dahlbom is the prosposed nomen protectum, in place of the unused names and prosposed nomina oblita, B. nivalis Dahlbom and B. tricolor Dahlbom. Therefore we consider Bombus balteatus Dahlbom to be the valid name for this species. Note 3 (tristis). The name tristis is published by Friese (1902) for a taxon as a variety alongside taxa given subspecific rank, so that infrasubspecific rank is clearly intended for the taxon tristis (ICZN 1999: Article 45.6.1). However, Skorikov (1937) uses tristis Friese for the name of a species, so that the taxon tristis Friese must be treated as having subspecific rank from the date of its original publication (ICZN 1999: Article 45.6.4.1). The name tristis was first published for an Alpinobombus taxon by Friese (1902), who described the taxon in a key couplet with the name attributed to Sparre-Schneider ‘ i. l. ’ (in litt.). Therefore Sparre-Schneider may have been the first to recognise the taxon as undescribed and may have supplied the name tristis. However, there is no evidence from Friese’s original publication that Sparre-Schneider was responsible for satisfying the other minimum criterion for availability (ICZN 1999: Article 12.1), that Sparre-Schneider supplied a description or diagnosis. Therefore the author of the nomenclatural act is deemed to be Friese (ICZN 1999: Article 50.1.1), not Sparre-Schneider. Note 4 (lysholmi). The name lysholmi was published by Friese (1905) for a taxon as a variety alongside other taxa given subspecific rank, so that infrasubspecific rank is clearly intended for the taxon lysholmi (ICZN 1999: Article 45.6.1). Subsequent references to this taxon before 1985 (e. g. Richards 1931; Skorikov 1937; Løken 1973) make no change to this status (ICZN 1999: Article 45.6.4.1). Taxonomy and variation. Bombus balteatus has often been considered to include B. kirbiellus but has recently been recognized as separate from evidence of a species coalescent in the COI gene (Williams et al. 2015; Fig. 9). Bombus balteatus is vicariant with B. kirbiellus across the Bering Strait (Figs. 59, 77). Variation in the colour pattern has been analysed previously (Williams et al. 2015). Colour variation is primarily in whether the pale hair of T 4 ‒ 5 is white (Figs. 60 ‒ 61, 67 ‒ 69, 71 ‒ 73, 76) or orange-red (Figs. 62 ‒ 66, 74 ‒ 75) and whether the yellow bands on the thorax and on T 1 ‒ 2 are present (Figs. 60 ‒ 64, 71 ‒ 74) or absent (Figs. 66, 69 ‒ 70, 75). The banded ‘ white-tailed’ colour pattern (Figs. 60 ‒ 61, 71 ‒ 73) is more prevalent in Scandinavia (often with a pinkish anterior margin on T 4: Fig. 73) and the banded ‘ orange-tailed’ colour pattern (Fig. 64) is the only one known from Mongolia. The unbanded orange-tailed colour pattern (Figs. 66, 75) is recorded from Norway and the unbanded (or weakly banded) white-tailed colour pattern (Figs. 69, 76) is more frequent from Kamchatka, especially from Karaginsky Island. One queen from Karaginsky Island is extensively black (Fig. 70). Colour-pattern variation of B. balteatus within Scandinavia has been mapped by Løken (1973: her figure 69). Within Scandinavia, B. balteatus shows a tendency towards an increased frequency of darker colour patterns in the more southern mountains. Entirely black individuals are not present in our sample. Pekkarinen (1979) recorded ‘ almost completely black’ Scandinavian males of B. balteatus.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFBA5E21FF685BC47176FB23.taxon	materials_examined	Material examined. 59 queens 61 workers 113 males (plus 425 females with caste undetermined), from Norway, Sweden, Finland, Russia, and Mongolia (Fig. 59: AB BP FB FO INHS MB MNHU NHMUK PW SD SEMC YPM ZISP), with 23 specimens barcoded. Several records are questionable. A record for four Russian females in the ZISP collection from near the southern border with Kazakhstan (# 905 ‒ 908) needs confirmation because the temper- ate low-elevation steppe habitat appears climatically unsuitable (cf. the Maxent climatic suitability model in Fig. 7). Similarly, southern records from near Krasnoyarsk (# 683, farmland / forest) and Khabarovsk (# 909, town / forest) appear to be from unsuitable low-elevation habitat and need to be confirmed. Habitat and distribution. Flower-rich arctic / alpine tundra and subalpine meadows in the Old World from the north of Scandinavia and Taymyr (but absent from Novaya Zemlya and Wrangel Island), extending southwards into the subarctic region in the alpine zone of the Kamchatka, Magadan-Sakha, Altay, Ural, and southern Scandinavian mountains. Regional distribution maps (Pittioni 1942; Løken 1973; Pekkarinen et al. 1981; Rasmont & Iserbyt 2012; Ødegaard et al. 2015; Rasmont et al. 2015). The records of this species by Milliron (1973) from Alaska and northern Canada are believed to be misidentifications (specimens examined resembling B. balteatus from Ellesmere Island have all proved to be dark individuals of B. kirbiellus).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFFBA5E21FF685BC47176FB23.taxon	description	Food plants. (Richards 1931; Berezin & Tkacheva 2012; Mossberg & Cederberg 2012) Behaviour. (Løken 1973; Svensson & Lundberg 1977; Berezin & Tkacheva 2012) Conservation status. This species has been assessed in part for Red List threat status using IUCN criteria (2001). Cederberg et al. (2013 b) assessed the Red List status of this species in Europe as ‘ Least Concern’ because of its broad distribution, its presumed large overall population described as stable, with no major threats. Subsequently, Rasmont et al. (2015) have assessed the risk from climate change to this species in Europe as ‘ very high climate change risk’ (HHR), projecting that it will suffer considerably from global warming.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF855E24FF685A8876EBFA8C.taxon	description	(Figs. 5, 77 ‒ 88, 133, 141, 146)	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF855E24FF685A8876EBFA8C.taxon	description	<Bombus> putnamii Cresson; von Dalla Torre 1896: 544, unjustified emendation.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF855E24FF685A8876EBFA8C.taxon	discussion	Note 1 (kirbiellus). The NHMUK is the most likely depository for the type material described by John Curtis from the British expedition led by John Ross to find the Northwest Passage. The type material has been believed to be lost (Franklin 1913: 291; Richards 1931: 15; Milliron 1973: 95) or to be ‘ not traced’ (Løken 1973: 105). Fortunately, there is an illustration of a queen accompanying Curtis’s original description (his plate A figure 2).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF855E24FF685A8876EBFA8C.taxon	description	The NHMUK collection does contain one queen (# 294) that could have been the model for Curtis’s illustration of B. kirbiellus. It is the only nineteenth century queen of this species in the NHMUK collection from the New World and it is also the only nineteenth century specimen of this species in the NHMUK collection that has been dried with the wings and legs extended, broadly as shown in the illustration in Curtis (which may have been rendered in a slightly more idealised, symmetrical pose). The lectotype queen of B. polaris (from the same expedition, see above) has been dried in a similar pose, but has a different colour pattern. The NHMUK queen (# 294) matches the Curtis illustration of B. kirbiellus in colour pattern, in that: (1) the hair on the top of the head posterior to the ocelli is predominantly black, so that it appears black from a distance, even though there is some yellow hair intermixed in this area as is frequent for this species; (2) there is a narrow but clear indication of black hair anterior and ventral to the wing bases, indicating a patch of black hair on the side of the thorax posteriorly in addition to the yellow hair anteriorly on the side of the thorax that is most frequent and often most extensive for this species; (3) metasomal tergum 2 posteriorly has black hair in a median triangle, which is infrequent for this species; (4) the hair of terga 4 ‒ 5 is a very pale pink-orange rather than the deep orange-red or yellow-white seen for many individuals. None of these colour-pattern characters is unique to this specimen, but no other candidate specimen is known with this combination of characters, so that this is the most likely specimen currently known as a candidate for the model for the illustration. There are nineteenth century New World queens of B. polaris in the NHMUK collection, but they all have a conspicuous band of yellow hair posteriorly on metasomal tergum 3, which is specifically excluded in the original description of B. kirbiellus. The NHMUK specimen (# 294) carries the labels: (1) white, handwritten ‘ Kirbiellus [female]. ’; (2) white, round, handwritten ‘ 40 / 4 – 2 / 1719 ’; (3) green, printed ‘ Alpinobombus / AL # 294. det. PHW’; (4) red, printed ‘ LECTOTYPE [female] / Bombus / kirbiellus / Curtis, 1835 / det. PH Williams 2014 ’; (5) white, printed ‘ Bombus / (Alpinobombus) / kirbiellus / det. PH Williams 2015 ’. The accession label (2) ‘ 40 / 4 – 2 / 1719 ’ refers (according to the NHMUK accessions register) to a specimen ‘ Bought at Mr Children’s sale’ in 1840. This is presumably a reference to John Children, who became Keeper of Zoology at the British Museum (BM), retiring in 1840. It is possible that Children may have acquired the specimen from Curtis through Children’s association with the BM. Smith (1854: 397) indicated that this species was present in the BM collection in 1854 (the entry for ‘ BOMBUS KIRBIELLUS’ is marked ‘ B. M. ’), represented by material from ‘ Boothia Felix’ (known to be visited at this time only by the Ross expedition), presumably therefore from Curtis. The hand-writing of the label (1) ‘ Kirbiellus [female]. ’ matches a sample of Curtis’s handwriting shown by Horn et al. (1935 ‒ 1937: plate XXXVIII no. 19) with a similar ‘ r’, ‘ b’, and ‘ e’. The ‘ s’ can be compared directly between the label and the sample published for Curtis, with a reduced upper section, and is more similar to Curtis’s handwriting than to the complete ‘ s’ shown for Frederick Smith (Horn et al. 1935 ‒ 1937: plate V no. 13), who worked on the bumblebee collection of the British Museum from 1849. However, the handwriting samples are too small to be conclusive. There is no single point of evidence that demonstrates beyond all doubt that this specimen (# 294) is one of Curtis’s syntypes, but in combination the evidence from the specimen’s appearance and from the labels is considered on the balance of probabilities to support this conclusion. The specimen has been re-pinned, but it is complete except that it lacks the terminal joints of the left hind tarsus and of the mid and hind right tarsi. This queen is designated here as lectotype in order to reduce uncertainty in the identity and application of the name, especially in relation to the closely similar species B. polaris that also occurs on Boothia. A conspecific male (# 293) in the NHMUK collection with an accession label ‘ 40 / 4 – 2 / 1718 ’ (also from the 1840 Children purchase) is also likely to be from the Ross expedition and is considered to be a paralectotype. Curtis (1835: lxiii) wrote that B. kirbiellus ‘ seemed to be the most abundant species’ [of bumblebee] seen on the Ross expedition, although it is likely that this included observations of the similar B. polaris. He gave the observation dates for most of the large female (queen) bumblebees (page lxiv) as June and July in 1830 and 1831. The main text of the report (e. g. page 566) places the expedition on these dates in the region around Cape Isabella on the isthmus of the Boothia Peninsula. Taxonomy and variation. Bombus kirbiellus has often been considered part of B. balteatus but has recently been recognized as separate from evidence of a species coalescent in the COI gene (Williams et al. 2015; Fig. 9). Bombus kirbiellus is vicariant with B. balteatus across the Bering Strait (Figs. 59, 77). Variation in the colour pattern has been illustrated and analysed previously (Williams et al. 2014 (under the name B. balteatus); Williams et al. 2015). The colour pattern with yellow on T 4 ‒ 5 (Figs. 78 ‒ 79) is known to us only from Nunavut. Otherwise the principal variation in this species is in whether the pale hair of T 4 ‒ 5 is predominantly orange (Figs. 80 ‒ 83, 85 ‒ 87) or predominantly black (Figs. 84, 88). The colour pattern from Lake Hazen on Elles- mere Island (Fig. 83) has the side of the thorax predominantly black, resembling some B. balteatus. Individuals with both the orange-tailed and black-tailed colour patterns share some of the same alleles, although there may be some variation in the relative frequency of the two patterns with latitude (Williams et al. 2015).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF855E24FF685A8876EBFA8C.taxon	materials_examined	Material examined. 257 queens 512 workers 307 males (plus 166 individuals with sex or caste undetermined), from USA and Canada (Fig. 77: AMNH BBSL CNC CSCA EMEC INHS JT LACM NHMUK PR PCYU PW PWRC RBCM RMBL ROM RSM RUAC SEMC UAM UCD UCMNH UOG WRMEYPM), with 27 specimens barcoded. A record for Bartlett Bay plotted for Ellesmere Island by Williams et al. (2014) is corrected here to Alaska from revised information on the location of this site (Mackovjak 2010). The records of B. balteatus in Milliron (1973) from Alaska and northern Canada are believed to be misidentifications of B. kirbiellus. Six dark specimens (# 1618, 3763 ‒ 3766, 4250) from the far north of Canada at Lake Hazen (Ellesmere Island), from samples taken in 1961, 1967, and 2010, have been identified here as B. kirbiellus. The nearest known populations of this species, probably on the Boothia Peninsula of Nunavut (Curtis 1835), appear to be distantly disjunct. This apparent gap is curious. Bombus kirbiellus was not recorded from Lake Hazen either by Milliron and Oliver (1966) or by Richards (1973). The species may be rare in northern Nunavut. The colour pattern from Lake Hazen has a dark side to the thorax, similar to some Old World individuals of B. balteatus, and is less easy to distinguish from the locally more abundant B. polaris. This difference in colour pattern from their relatives further south in the New World makes a recent introduction from the southern population a less likely explanation of the apparently isolated Lake Hazen population. Alternatively these northern bees could be a relic from a darker population that was once more widespread during a previous warm interglacial period. Habitat and distribution. Flower-rich arctic / alpine tundra and subalpine meadows in the New World excluding Greenland, north to the Boothia Peninsula as well as disjunctly in Ellesmere Island and east to Newfoundland, extending southwards into the subarctic region in the Aleutian Islands and Hudson Bay, and in the alpine zone of the southern Rocky and Californian Sierra Nevada mountains. Regional distribution maps (Milliron 1973; Thorp et al. 1983; Laverty & Harder 1988; Williams et al. 2014).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF855E24FF685A8876EBFA8C.taxon	description	Food plants. (Milliron 1973; Thorp et al. 1983; Williams et al. 2014) Behaviour. (Hobbs 1964) Conservation status. This species has not yet been fully assessed for Red List threat status using IUCN criteria (2001). Hatfield et al. (2016 a) have listed B. kirbiellus as ‘ Data deficient’.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF805E26FF685B3B742AFC24.taxon	description	(Figs. 89 ‒ 103, 134, 143, 145, 148) B. <ombus> strenuus Cresson 1863: 102 (not of Harris 1776: 131, = B. lapidarius (Linnaeus )), type-locality citation ‘ Youcon River, Arctic America, and Hudson’s Bay Territory’. Lectotype queen (# 4706) by designation of Cresson 1916: 131, ANSP examined PW, ‘ H. B. T. ’ [Hudson Bay Territory] (? Nunavut, Canada).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF805E26FF685B3B742AFC24.taxon	description	Taxonomy and variation. Bombus neoboreus has long been treated as including B. kluanensis but has been recognized as separate from evidence of a species coalescent in the COI gene (Williams et al. 2015; Fig. 9), differences in morphology and differences in the PEPCK gene (Williams, Cannings, et al. 2016). Variation in the colour pattern has been illustrated and analysed previously (Williams et al. 2014; Williams et al. 2015). The pale colour pattern B. strenuus Cresson was described as having the hair of the dorsal part of the side of the thorax, the scutellum, and T 1 ‒ 3 extensively yellow (Figs. 90 ‒ 93, 101 ‒ 102). This is the most widespread colour pattern of the species. The principal variation is in whether T 5 is predominantly orange (Figs. 90, 92 ‒ 93, 101 ‒ 102) or predominantly black (Fig. 91), although there are usually a few orange hairs present. Later, the darker colour pattern B. neoboreus was described, which has the dorsal part of the side of the thorax, the scutellum, and T 3 extensively black (Figs. 94 ‒ 100, 103). The darkest females have the top of the head, side of the thorax, scutellum, middle third of T 1, and T 3 ‒ 5 black (Fig. 97). There are especially many individuals of the dark colour pattern neoboreus s. str. in collections from Nunavut: near Coppermine, Bernard Harbour, and Kugluktuk. They are superficially similar to some B. polaris, but are slightly larger, with shorter hair, have a longer oculomalar distance, and have a smoother shinier outer corbicular surface of the hind tibia. Individuals with both colour patterns (the pale strenuus and the dark neoboreus s. str.) co-occur at Kluane (Yukon) and at Coppermine (Nunavut) and there are no diagnostic differences in their COI barcodes.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF805E26FF685B3B742AFC24.taxon	materials_examined	Material examined. 58 queens 104 workers 100 males (plus 5 females with caste undetermined), from the USA and Canada (Fig. 89: AMNH ANSP CNC INHS NHMUK NMNH PCYU PR PW RBCM RSKM RSM UAM YPM), with 15 specimens barcoded. A record of a queen from a site on Vancouver Island (# 4298) was noted by Milliron (1973) as needing confirmation. The specimen (CNC) is correctly identified, but the site is unexpectedly far south for this species and at low elevation, apparently in unusual forest habitat for this species (cf. the Maxent climatic suitability model in Fig. 7), so the specimen may have been mislabelled. Habitat and distribution. Flower-rich arctic / alpine tundra in the New World tundra excluding Greenland, north to Prince Patrick Island and east to Victoria Island, extending southwards into the subarctic region in the alpine zone of the Alaskan and Yukon mountains. Regional distribution maps (Milliron 1973; Williams et al. 2014).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF805E26FF685B3B742AFC24.taxon	description	Food plants. Unknown. Behaviour. Unknown. Conservation status. This species has not yet been fully assessed for Red List threat status using IUCN criteria (2001). Hatfield et al. (2016 c) have listed B. neoboreus as ‘ Data deficient’. Their data appear to include data for B. kluanensis.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF825E29FF685D947775FEC1.taxon	description	(Figs. 10, 104 ‒ 115, 135, 149) [Megabombus (M. <egabombus>) strenuus (Cresson); Milliron 1973: 110, misidentification.] [unnamed Williams et al. 2015: 3]	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF825E29FF685D947775FEC1.taxon	discussion	Taxonomy and variation. Bombus kluanensis has long been considered part of B. neoboreus but was recognized as a separate species based on evidence of a species coalescent in the COI gene and differences in the PEPCK gene as well as from differences in morphology (Williams et al. 2015; Williams, Cannings, et al. 2016). Support from bGMYC analysis for separation of B. kluanensis, B. natvigi, and B. hyperboreus, was not as high as for the other species of Alpinobombus (Williams et al. 2015), but B. kluanensis is easily distinguished from B. natvigi and B. hyperboreus by its social behaviour with abundant workers. Bombus kluanensis was first collected in 1913 by A. Pattison and H. Lambart as two queens from the Klutlan Glacier (Yukon), which are now in the CNC (# 2305, 2306). These specimens were included in Milliron’s review of the western hemisphere bumblebee fauna (Milliron 1973) as part of B. strenuus Cresson (a junior secondary homonym in Bombus of Apis strenuus Harris), the name used by Milliron (1973) for B. neoboreus. According to labels on the two specimens, both were also identified by R. B. Miller in 1987 as ‘ B. strenuus Cresson’ (see the comments on B. neoboreus). In 1971 and 1972, L. W. Macior collected a series of 18 queen and 222 worker specimens of B. kluanensis from Kluane (Yukon), which are now in the NMNH collection (# 4409 ‒ 4454, 4457 ‒ 4468, 4473, 4475 ‒ 4507, 4509 ‒ 4518, 4530 ‒ 4554, 4556 ‒ 4613, 4615 ‒ 4621, 4625 ‒ 4628, 4637 ‒ 4661, 4664, 4666, 4670 ‒ 4675, 4681 ‒ 4684, 4686, 4689, 4691 ‒ 4692, 4696 ‒ 4697, 4700). These specimens were not included by Milliron (1973). According to labels on these specimens, they were again identified by R. B. Miller in 1986 as ‘ B. strenuus Cresson’ (= B. neoboreus). The Kluane specimens were not examined by one of us (PW) until 2015.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF825E29FF685D947775FEC1.taxon	description	Bombus kluanensis was first recognized as different from B. neoboreus by one of us (PW) from the COI barcodes of two specimens collected by SC in the Saint Elias Mountains of the Yukon during 2010 (# 16, 17). These barcodes were later matched with others for specimens from Alaska (# 4392 ‒ 4394). In a subsequent guide to North American bumblebees, Williams et al. (2014: 105) described this observation as ‘ Evidence from DNA barcodes appears to show that this species [then B. neoboreus s. l.] is not a single natural group (i. e., it is paraphyletic [when including B. kluanensis]) without including B. hyperboreus [s. l., including B. natvigi] ’. Six specimens collected in 2010 ‒ 2016 (# 16, 17, 4392 ‒ 4394, 4870: geographical distribution mapped in Fig. 10: green spots) were sequenced for COI barcodes and found to differ from B. neoboreus at 18 COI base positions and at three PEPCK base positions (Williams et al. 2015; Williams, Cannings, et al. 2016). These specimens were described under the name B. kluanensis (holotype specimen # 16, Fig. 107), along with many of the specimens col- lected earlier that had not previously been recognized as a separate species. Females of B. kluanensis identified from COI have the oculo-malar area (cheek) longer (1.31 ‒ 1.40 times longer than the breadth of the mandible at its base) than in B. neoboreus (1.12 ‒ 1.21 times longer than broad) as reported by Williams et al. (2016). Compared to the pale colour pattern of B. neoboreus (colour pattern strenuus), for B. kluanensis females have the upper two thirds of the side of the thorax is yellow but with few or many black hairs intermixed, T 3 is yellow but often with black hairs intermixed anteriorly (whereas both of these areas have few black hairs in many B. neoboreus), and T 4 ‒ 6 are usually entirely black (Figs. 107 ‒ 109), rarely with many orange hairs on T 5 ‒ 6 (e. g. L. Macior specimens in Figs. 105 ‒ 106) (T 5 ‒ 6 usually have at least a few orange hairs in B. neoboreus: Figs. 90, 92 ‒ 93). The first worker recognised of B. kluanensis (# 17) has the hair of T 6 predominantly orange. Compared to the dark colour pattern of B. neoboreus (neoboreus s. str.), for B. kluanensis the scutellum always has a broad yellow band (Williams, Cannings, et al. 2016). Two older females (L. Macior specimens in Figs. 110 ‒ 111), tentatively associated with B. kluanensis, have T 3 and the side of the thorax almost entirely black, resembling B. natvigi. For an analysis of the principal aspects of the colour polymorphism see Williams et al. (2015). Another 15 specimens collected in 2015 ‒ 2017, (# 4849 ‒ 4855, 4869, 4872, 4873, 4979 ‒ 4984: distribution mapped in Fig. 10: red spots) that appeared from morphology to be B. kluanensis were barcoded but found to differ from the earlier sequences of B. kluanensis s. str. at 10 COI base positions. This is sufficient for the PTP analysis to show that they might represent a separate candidate species (Fig. 9), which is labelled here ‘ unnamed 2 ’. Morphological and colour characters in the keys distinguish all species of Alpinobombus but do not distinguish between individuals with the two COI alleles. Furthermore, differences in 16 S distinguish among all species of Alpinobombus but do not distinguish between individuals with the two COI alleles, B. kluanensis s. str. and ‘ unnamed 2 ’ (see the Results). The most likely explanation is paralogy in COI (Figs. 9, 11) with incomplete lineage sorting and mitochondrial heteroplasmy (see the Results). In our data, B. kluanensis s. str. and ‘ unnamed 2 ’ uniquely within Alpinobombus show two gel bands and one individual (# 4850) appears to have yielded both the kluanensis s. str. (as sequence NHM-CT- 4850) and the ‘ unnamed 2 ’ (as sequence CCDB- 25141 - A 05) alleles. The geographical distributions of the two alleles are broadly coincident, showing no obvious pattern of geographical segregation (Fig. 10). Consequently, until more information is available, we regard ‘ unnamed 2 ’ as likely to be conspecific with B. kluanensis s. l. (Fig. 13). Further investigation of this taxon is needed. Description of the male. Morphology. Body length 16 ‒ 20 mm. Hair (pubescence) moderately long and even, wings clear. Mandible with the posterior fringe (‘ beard’) unusually sparse, the outer surface of the mandible nearly covered with an extremely dense thick brush of moderately long, plumose, pale orange hair (which may appear dark if matted) forming a pronounced thick dense rounded pad extending from the basal mandibular articulations to just short of the apical mandibular teeth (Fig. 149: it is unknown whether this unique structure has a special function). Oculo-malar area long, 2.1 × longer (length measured between the ventral edge of the compound eye and the edge of the malar area at the articulation of the mandible midway between the mandibular condyles) than the breadth of the mandible at its base (breadth between and including the mandibular condyles). Eye similar in relative size and shape to the eye of any female bumblebee. Antenna of medium length, the flagellum 3 × longer than the scape. Genitalia (Fig. 135) with the gonostylus inner (medial) edge between the anterior and posterior inner corners nearly straight dorsally, ventral to the submarginal groove with three broad shallow inner (medial) lamellate projections, the inner corners projecting slightly; volsella in ventral view broad in its mid section, narrowing gradually in its posterior section to just anterior to the inner process; penis-valve head on its outer edge proximal to the apex by a distance approximately equal to the breadth of the penis-valve head without a tooth. Colour pattern of the hair (Figs. 112 ‒ 115). Hair of the body predominantly black. Head ventral to the antennal base with a large patch of yellow with black hairs intermixed; top of the head posterior to the ocelli with a large patch of yellow. Thoracic dorsum with broad anterior and posterior yellow bands, each less broad than the black band between the wing bases (with some yellow hairs intermixed), some black hairs intermixed posteriorly on the scutellum; side of the thorax with black and yellow hairs intermixed. Foreleg and midleg with pale hairs posteriorly; hind femur ventrally with pale hairs, tibia and tarsus with long fringing hairs pale orange. Metasomal T 1 ‒ 3 yellow (Fig. 112), T 3 anteriorly often with many black hairs intermixed (Fig. 113 ‒ 114), predominating on T 3 anteriorly in one individual (Fig. 115); T 4 black sometimes with yellow hairs intermixed in the posterior lateral corners; T 5 ‒ 7 black with a few hairs laterally with pale tips.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF825E29FF685D947775FEC1.taxon	materials_examined	Material examined. 30 queens 244 workers 8 males (plus 3 females with caste undetermined), from Canada and the USA (Fig. 104: CNC HUM NHMUK NMNH PW RBCM RSKM UAM YPM), with 22 specimens barcoded. Habitat and distribution. Flower-rich alpine tundra and subalpine meadows of the St Elias Mountains near Kluane in the Yukon and in the Denali National Park in the Alaska Range of Alaska (Figs. 10, 104).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF825E29FF685D947775FEC1.taxon	description	Food plants. Unknown. Behaviour. Unknown. Conservation status. Unassessed.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF8D5E29FF685FE77685F879.taxon	description	(Figs. 116 ‒ 123, 136, 144)	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF8D5E29FF685FE77685F879.taxon	description	[<Alpinibombus hyperboreus> mod. natvigoides, mod. henrikseni Skorikov 1937: 57, infrasubspecific.] BOMBUS (ALPINOBOMBUS) HYPERBOREUS <ssp.> CLYDENSIS Yarrow 1955: 151, type-locality citation ‘ Clyde Inlet, Baffin Island’. Holotype queen (# 184) by original designation, NHMUK examined PW, ‘ Clyde Inlet / Baffin Id’ (Nunavut, Canada). Synonymisation with Bombus natvigi Richards suggested by Williams et al. (2016: 2), confirmed here. Taxonomy and variation. Bombus natvigi has long been considered part of B. hyperboreus but has been recognized as separate from evidence of a species coalescent in the COI gene (Williams et al. 2015; Fig. 9). The support from bGMYC analysis for separation of B. kluanensis, B. natvigi, and B. hyperboreus, was not as high as for the other species of Alpinobombus (Williams et al. 2015), but B. kluanensis is easily distinguished by its social behaviour with abundant workers. Bombus natvigi is vicariant with B. hyperboreus across the Bering Strait (Figs. 116, 124). Variation in the colour pattern has been illustrated and analysed previously (Williams et al. 2014 (under the name B. hyperboreus); Williams et al. 2015). There is little variation in most females (Fig. 118), with occasional individuals having yellow hair intermixed on the upper side of the thorax (Fig. 117). Males show greater variation, with intermixing of yellow hair extensively on the thorax (Figs. 119 ‒ 121) and on T 5 ‒ 6 (Fig. 119), occasionally with orange hair on T 6 ‒ 7 (Fig. 119).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF8D5E29FF685FE77685F879.taxon	materials_examined	Material examined. 223 females 134 males, from USA, Canada, and Greenland (Fig. 116: AMNH BP CNC CR EMEC HUM INHS NHMUK PR PCYU PW RBCM ROM UAM UOG YPM ZISP), with 23 specimens barcoded. Habitat and distribution. Flower-rich arctic / alpine tundra in the New World including Greenland, north to Ellesmere Island and north Greenland, extending southwards into the subarctic region in the alpine zone of the Alaskan and Yukon mountains (but absent from the Aleutian Islands: records in Milliron 1973 and Richards 1973 are revised here to B. polaris). Regional distribution maps (Milliron 1973; Richards 1973; Williams et al. 2014).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF8D5E29FF685FE77685F879.taxon	description	Food plants. (Richards 1931; Milliron & Oliver 1966; Milliron 1973; Richards 1973; Williams et al. 2014) Behaviour. Some authors have reported workers of B. natvigi (from the New World but under the name B. hyperboreus: Milliron 1973), but we have seen no convincing workers of this species during this study (although some workers of B. kluanensis may be very similar in colour pattern, Fig. 110, and in head shape). Milliron and Oliver (1966) and Richards (1973) interpreted this scarcity of workers as evidence that the species is a social parasite in colonies of other bumblebee species. In this respect B. natvigi is almost unique among bumblebees other than the species of the subgenus Psithyrus (the other exceptions are B. hyperboreus, below, and B. inexspectatus (Tkalců), see Müller 2006). The host species of B. natvigi has been identified as B. polaris (Milliron & Oliver 1966; Richards 1973; Pape 1983). Despite this, some females of B. natvigi (under the name B. hyperboreus) occasionally have compressed pollen in their corbiculae (see comments on B. hyperboreus), which appears to be evidence of foraging for a colony (Pape 1983). There is no evidence of protective mimicry of the host (B. polaris) in cephalic gland secretions and none of the repellent compounds detected from parasitic Psithyrus bumblebees have been identified (Brasero, Martinet, et al. 2017). Conservation status. This species has not yet been fully assessed for Red List threat status using IUCN criteria (2001). Hatfield et al. (2016 b) have listed B. natvigi as ‘ Data deficient’.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF8F5E2EFF685EF471A3FDE0.taxon	description	(Figs. 6, 124 ‒ 128, 137)	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF8F5E2EFF685EF471A3FDE0.taxon	description	Note 1 (arcticus). Nilsson (2009: 53) described the history of the single type specimen of Apis arctica Quensel (spelled Quenzel in the original publication). Note 2 (hyperboreus). Nilsson (2009: 53) gave an account of the redescription of the type specimen of Apis arctica Quensel as Bombus hyperboreus Schönherr, which is therefore an objective junior synonym. Milliron’s (1960: 93) designation of the single original specimen as lectotype is invalid as stated by Løken (1973: 114; agreed by Nilsson 2009: 53), because in the original description the species was identified as having been based on a single specimen, which is therefore the holotype by monotypy (# 4844). Løken (1973: 114) considered B. arcticus (Quensel) to be a nomen oblitum, so she continued to use the name B. hyperboreus Schönherr. However, nomina oblita are not supported for a publication of the date of Løken’s work (after 1 January 1973) by the now current Code (ICZN 1999: 111), although this status could be supported after 1 January 2000 as recognised later by Nilsson (2009: 54) according to this Code (ICZN 1999: Article 23.9). There is strong support for the claim that B. hyperboreus Schönherr is the stable valid name because both criteria required by the current Code (ICZN 1999) are essentially met: first (Article 23.9.1.1), that the senior synonym B. arcticus (Quensel) has not been used as a valid name after 1899 (most uses of B. arcticus for this species being instead misidentifications of B. arcticus Kirby following Franklin 1913: 302; which according to Richards 1931: 9, include Meade-Waldo 1916: 469, Sladen 1919: 28, and Lutz & Cockerell 1920: 507), with the sole exception of Michener (2000: 789); and second (Article 23.9.1.2), that the junior synonym B. hyperboreus Schönherr has been used for this well known taxon as its presumed valid name in more than 25 works, published by at least 10 authors in the preceding 50 years (since 1968: e. g. Richards 1968; Løken 1973; Sakagami 1976; Svensson & Lundberg 1977; Pekkarinen 1979; Pekkarinen et al. 1981; Reinig 1981; Rasmont 1983 a; Williams 1989, 1991; Pekkarinen & Teräs 1993; Williams 1998; Koulianos & Schmid-Hempel 2000; Pedersen 2002; Goulson 2003; Hines et al. 2006; Cameron et al. 2007; Holmström 2007; Gjershaug 2009; Nilsson 2009; Ebmer 2011; Mossberg & Cederberg 2012; Rasmont & Iserbyt 2012; Cederberg et al. 2013 c; Potapov et al. 2014; Ødegaard et al. 2015; Rasmont et al. 2015). The use by Michener (2000) of B. arcticus (Quensel) as the valid name (contrary to the recommendations of Løken 1973: 114, and of Williams 1998: 119) can be construed as deliberately contrary to Article 23.9.1 because he wrote that the species is ‘ usually known as’ B. hyperboreus Schönherr, so that this instance of usage can be discounted (ICZN 1999: Article 23.9.6). Therefore we consider Bombus hyperboreus Schönherr to be the valid name for this species. Taxonomy and variation. Bombus hyperboreus has long been considered to include B. natvigi but has been recognized as separate from evidence of a species coalescent in the COI gene (Williams et al. 2015; Fig. 9). The support from bGMYC analysis for separation of B. kluanensis, B. natvigi, and B. hyperboreus, was not as high as for the other species of Alpinobombus (Williams et al. 2015), but B. kluanensis is easily distinguished by its social behaviour with abundant workers. Bombus hyperboreus is vicariant with B. natvigi across the Bering Strait (Figs. 116, 124). Variation in the colour pattern has been analysed previously (Williams et al. 2015). There is very little variation in this species and this is primarily in the hue of the pale bands, from pale yellow on Wrangel Island (Fig. 125) to the more common chestnut brown (Figs. 126, 128).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF8F5E2EFF685EF471A3FDE0.taxon	materials_examined	Material examined. 70 females 1 worker 92 males, from Norway, Sweden, Finland, and Russia (Fig. 124: AB BP FO MB NHMUK NHRS PW YPM ZISP), with 16 specimens barcoded. Habitat and distribution. Flower-rich arctic / alpine tundra in the Old World from the far north of Scandinavia, Taymyr, Novaya Zemlya and Wrangel Island, extending southwards into the subarctic region in the alpine zone of the Magadan and Scandinavian mountains. Regional distribution maps (Løken 1973; Richards 1973; Pekkarinen et al. 1981; Rasmont & Iserbyt 2012; Ødegaard et al. 2015; Rasmont et al. 2015).	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
AC4D691FFF8F5E2EFF685EF471A3FDE0.taxon	description	Food plants. (Richards 1931; Richards 1973; Mossberg & Cederberg 2012) Behaviour. Bombus hyperboreus is almost unique among bumblebees other than species of the subgenus Psithyrus (the other exceptions are B. natvigi, above, and B. inexspectatus (Tkalců), see Müller 2006) in being recorded as a parasite in colonies of other bumblebees. The host species is especially B. pyrrhopygus (under the name B. polaris, Friese 1935; Løken 1973; Pape 1983), but there are also recent records as hosts for B. balteatus (Gjershaug 2009), and B. (Pyrobombus) jonellus (Kirby) (Bergwall 1970). Five females of B. hyperboreus in the NHMUK collection (# 182, 189, 197, 198, 200) have substantial amounts of compressed pollen in their corbiculae, which appears to be evidence of foraging for a colony, as reported previously from Europe (Gjershaug 2009). Pollen in a corbicula is also shown for the female in Fig. 6, which is foraging on Astragalus alpinus L .. Females have been observed showing ‘ nest-seeking’ behaviour (Svensson & Lundberg 1977). Some authors have reported workers of B. hyperboreus (Enwald 1881; Skorikov 1923; Elfving 1960; Løken 1973), but we have seen only one convincing worker of this species in this study, from Norway (# 3855) (Ødegaard et al. 2015). There is no evidence of mimicry of the host (B. pyrrhopygus) in cephalic gland secretions and none of the repellent compounds identified from parasitic Psithyrus bumblebees were detected (Brasero, Martinet, et al. 2017). Conservation status. This species has been assessed for Red List threat status using IUCN criteria (2001). Cederberg et al. (2013 c) assessed the Red List status of this species in Europe as ‘ Vulnerable’ because its known area of occupancy (AOO) for Europe is small (420 km ²) and because it is experiencing a continuing decline due to declines in its host, B. pyrrhopygus (under the name B. polaris), and climate warming. Subsequently, Rasmont et al. (2015) have assessed the risk from climate change to this species in Europe as ‘ extremely high climate change risk’ (HHHR), projecting that climate change will very likely lead to its extirpation from Europe.	en	Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat, Byvaltsev, Alexandr M. (2019): The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus). Zootaxa 4625 (1): 1-68, DOI: 10.11646/zootaxa.4625.1.1
