Bombus marussinus Skorikov

Williams, Paul H., Huang, Jiaxing, Rasmont, Pierre & An, Jiandong, 2016, Early-diverging bumblebees from across the roof of the world: the high-mountain subgenus Mendacibombus revised from species’ gene coalescents and morphology (Hymenoptera, Apidae), Zootaxa 4204 (1), pp. 1-72 : 40-41

5. Bombus marussinus Skorikov

( Figs 15 , 28 , 55 , 60 )

< Bombus mendax > subsp. marussinus Skorikov 1910b:330 , type-locality citation (Cyrillic) ‘[ East Pamir ]’. Lectotype queen by present designation ZISP examined, (Cyrillic) ‘[Shugnan, Pamir]’ (Pamir, Tajikistan). Note 1.

[ Bombus mendax var. aberrans Skorikov 1910b:330 , infrasubspecific.]

Mendacibombus mendax subsp. marussinus ( Skorikov); Skorikov 1914 :124.

Mendacibombus marussinus ( Skorikov); Skorikov 1923 :149; Skorikov, 1931:215; Tkalců 1969:192.

[ Bombus mendax marussinus aberrans Skorikov ; Reinig 1930:100, infrasubspecific.]

[ Bombus mendax marussinus aberrans zonatus Reinig 1930:101, infrasubspecific.]

Bombus (Mendacibombus) mendax Subsp. marussinus Skorikov ; Richards 1930:634.

Bombus mendax marussinus Skorikov ; Reinig 1932b:158.

Bombus (Mendacibombus) marussinus Skorikov ; Reinig 1932a:258; P.H. Williams 1991:44; P.H. Williams 1998:99; P.H. Williams 2004:no. 28; Suhail et al. 2009:3 [not seen].

[ Bombus (Mendacibombus) marussinus f. aberrans Skorikov; Reinig 1932a:258, infrasubspecific.]

[ Bombus (Mendacibombus) marussinus f. zonata Reinig; Reinig 1932a:258, infrasubspecific.]

Bombus marussinus Skorikov ; Reinig, 1934:172; Sabir et al. 2011:161 [not seen].

Bombus (Mendacibombus) marussinus <subsp.> afghanus Reinig 1940:230 , type-locality citation ‘ Chodja-Mahomed’ (Kwaja Muhammed, Badakhshan, Hindu Kush, Afghanistan). Syntype queen and male presumed lost by Tkalců 1969.

Note 1 ( marussinus ). Skorikov’s original description of the taxon marussinus cites the type locality as east Pamir. The ZISP collection studied by Skorikov contains a queen that agrees with the original description and carries the labels: (1) white, printed (Cryrillic) ‘[r. Toguz-bulak / V. Shugnan, Pam. / Makarin] 24/27.VI 09.’; (2) white, printed (Cyrillic) ‘[k. Skorikova]’; (3) white, handwritten in pencil ‘[illegible] / N 14’; (4) red, handwritten ‘ Lectotypus Bombus / mendax subsp. / marussinus Skor. / design. Podbolotsk. ’ (M. Podbolotskaya, unpublished); (5) green, printed ‘ Mendacibombus / MD# 736 det. PHW’; (6) red, printed ‘ LECTOTYPE [female] / Bombus mendax ssp. / marussinus / Skorikov, 1910 / det. PH Williams 2012’; (7) white, printed ‘[female] Bombus / ( Mendacibombus ) / marussinus / det . PH Williams 2012’. This specimen, which is complete, is regarded as one of Skorikov’s syntypes (others may have existed, it is unclear) and is designated here as the lectotype in order to reduce uncertainty in the identity and application of the name.

Etymology. The species may be named after a Russian entomologist, P. Marusin, from Tashkent (A. Byvaltsev, in litt.).

Taxonomy and variation. The single composite COI sequence supports this as a separate species ( Fig. 11 ). The interpretation of this taxon as a separate species is also supported by the distinct form of the female labrum and of the male genitalia. This disagrees with earlier concepts ( Tkalců, 1969), diagnosed originally in terms of the colour pattern of the hair ( Skorikov, 1910b), because the species appears to be not as easily diagnosable by colour (cf. B. avinoviellus ) as originally understood.

All specimens have yellow and none has white hair on the thoracic dorsum or a black band between the wing bases. Skorikov (1910b) described females of the taxon marussinus s. str. from the Pamir (MD#736) as having the corbicula framed with light hairs, with T1‒2 light yellow, the side of the thorax yellow above and whitish below, and the ventral side of the metasoma light (yellow). The palest specimens from the Pamir have T2 almost white (MD#1191).

For some specimens from further south in the Hindu Kush there is variation in the replacement of yellow with black on T2 and on the lower side of the thorax (Reinig’s taxon afghanus ) although we have no COI sequences (from the taxon marussinus s. str.) from which to confirm this. Geographically associated males with the two colour patterns share the same diagnostic form of the male genitalia. The form of the female labrum is also diagnostic in grouping the taxa together. These specimens are interpreted as conspecific, as parts of the species B. marussinus s. l. (all of our COI sequences come from specimens from Pakistan with this dark colour pattern: MD#407, 408, 410).

Tkalců (1969) subsequently applied the name Mendacibombus afghanus to a series of specimens from the Karakorum that, in addition to the dark hair of T2, have darker wings and predominantly black hair on T6 (as opposed to predominantly orange for B. marussinus ), treating them as a separate species. These darker Karakorum specimens (but not those with a similar colour pattern from the Hindu Kush) are interpreted here as likely to be conspecific with B. avinoviellus (see the comments on that species).

Diagnostic description. Wings nearly clear (cf. B. avinoviellus ). Female hair colour pattern: generally black, but with yellow hair in a large patch below the base of the antenna, in a small patch on the vertex of the head, on the entire thoracic dorsum (at most with an obscure small round patch of black hairs between the wing bases, cf. B. himalayanus ) and extending laterally and ventrally to half way down the side of the thorax, or to all of the way to the midleg base, on T1, on T2 anteriorly and medially or sometimes all of T2 except for a few black hairs intermixed medially along the posterior margin, T3 varying from orange only as a narrow posterior fringe to orange except for some black hairs anteriorly, and T4‒6 orange, except T6 usually dominated medially by long black hairs. Hindleg tibia with the corbicular fringes often appearing double: hairs on the corbicular surface and in the adjacent fringes are usually black, sometimes with orange tips, but exterior to this, the hair in the outer fringes (anteriorly and posteriorly) may be black or yellow (cf. B. himalayanus , B. avinoviellus ). Female morphology: labrum with the basal depression narrow, the transverse ridge broader medially than the basal depression, in the median third convex throughout, not subsiding completely or interrupted and with only a few scattered medium punctures, the lateral tubercles smooth with very few punctures ( Fig. 15 ) (cf. B. himalayanus , B. avinoviellus ). Clypeus in its central half with few scattered punctures, almost as many large as small punctures (cf. B. avinoviellus ). Male morphology: genitalia ( Fig. 28 ) with the volsella distally rounded (finger-shaped) and curled back dorsally but not anteriorly; volsella at its broadest near the midpoint of its length, the dorsal surface just distal to this point without a raised curved ridge just inside the inner margin; volsella with the apex broad, broader than the adjacent penisvalve head, but with the apex narrowly produced and finger-like. Gonostylus from the dorsal aspect almost triangular, without a distinct outer distal corner but broadly rounded. Penis-valve inner shoulder located at Ĺ 0.5× the length of the penis valve from the distal end to the broadest point of the spatha; penis valve proximal to the outer shoulder <2× as broad as the penis-valve head; penis-valve breadth just proximal to penis-valve head 0.11× the length of the penis valve distal to the broadest point of the spatha.

Material examined. 9 queens 86 workers 17 males, from Afghanistan, Pakistan, and Tajikistan ( Fig. 60 : NHM, PW, RMNH, UMONS, ZISP), with 3 specimens sequenced (interpretable sequences listed in Figs. 1 1–13 ) .

Habitat and distribution. Flower-rich alpine grassland (not seen by us), at elevations 2800‒(3787)‒ 4500 m a.s.l.. A species of the Pamir, Hindu Kush, and Karakorum mountains. There is some overlap with B. makarjini in the Pamir, there is some overlap with B. turkestanicus in the Pamir and Hindu Kush, and there is some overlap with B. himalayanus in the northwestern Karakorum, but in these cases the two seldom occur together. A regional distribution map is available for Kashmir ( P.H. Williams 1991).

Food plants. No records.

Behaviour. No records.

Figures

FIGURES 15 ‒ 23. Morphology of the female (queen) head from the ventral aspect (labrum and mandibles): 15, B. marussinus queen, Pakistan MD # 482; 16, B. avinoviellus queen, India MD # 598; 17, B. turkestanicus queen, Tajikistan MD # 320; 18, B. defector queen, Kyrgyzstan MD # 1080; 19, B. margreiteri queen, Mongolia MD # 319; 20, B. himalayanus queen, India MD # 453. Morphology of the female (queen) left hindleg tibia from the left lateral aspect, dorsal at the top of the image, anterior to the left: 21, B. defector, China MD # 1251; 22, B. margreiteri, Mongolia MD # 319; 23, B. turkestanicus, Kyrgyzstan MD # 324.

FIGURES 24 ‒ 35. Morphology of the male genitalia for species of the subgenus Mendacibombus from the dorsal aspect, anterior to the left of the image, posterior to the right: 24, B. superbus, China MD # 339; 25, B. waltoni, China MD # 216; 26, B. convexus, China MD # 215; 27, B. makarjini, Kazakhstan MD # 1240; 28, B. marussinus, Pakistan MD # 408; 29, B. avinoviellus, India MD # 404; 30, B. himalayanus, India MD # 426; 31, B. turkestanicus, China MD # 351; 32, B. defector, Kyrgyzstan MD # 367; 33, B. margreiteri, China MD # 294; 34, B. handlirschianus, Russia MD # 835; 35, B. mendax, Spain MD # 689.

FIGURES 36 ‒ 55. Morphology of parts of the male genitalia from the dorsal aspect of the left side, anterior to the left of the image, posterior to the right, white bars indicating morphological characters referred to in the key to males: 36, B. waltoni; 37, B. mendax; 38, B. superbus; 39, B. convexus; 40, B. waltoni; 41, B. convexus; 42, B. defector; 43, B. mendax; 44, B. mendax; 45, B. turkestanicus; 46, B. avinoviellus; 47, B. mendax; 48, B. mendax; 49, B. makarjini; 50, B. handlirschianus; 51, B. himalayanus; 52, B. turkestanicus; 53, B. himalayanus; 54, B. himalayanus; 55, B. marussinus.

FIGURES 56 ‒ 67. Maps of the global distributions of species of the subgenus Mendacibombus from the material examined, with grey spots for specimen records and black spots for the samples with COI sequences (each species is unknown from regions outside the map boundaries shown); grey crosses for records of all species of Mendacibombus combined. Relief map with hill shading, Cartesian orthonormal projection, grey lines show borders to national administration according to UN maps, north at the top of the map. Image created in ArcGIS using World _ Shaded _ Relief basemap © 2014 Esri.

FIGURES 11 ‒ 12. Recognising species from an estimate of phylogeny for 30 unique COI haplotypes of the subgenus Mendacibombus by BEAST, using GMYC models and the PTP procedure. From the GMYC models (11), the single threshold T is shown by the vertical grey bar so that the intersecting lineages are interpreted as indicating 12 separate species (black spots at coalescent nodes; outgroups not shown). Values below the nodes of the maximum clade-credibility tree are Bayesian posterior probabilities showing branch support (groups with values <0.8 are considered unreliable) from the BEAST analysis with two billion MCMC generations and a 1 % burn-in. The x - scale axis is calibrated in substitutions per nucleotide site. From the PTP procedure (12), the Bayesian PTP solution with highest support also indicates 12 species. Values above the nodes are PTP Bayesian support values that all daughter haplotypes are parts of a single species; values below the nodes are Bayesian posterior probabilities showing branch support. The scale bar is calibrated in substitutions per nucleotide site. Each unique haplotype is represented by one of the longest available sample sequences, labelled with: the sequence length in number of base pairs, a taxon name or name for an unpublished colour pattern (light / dark / yellow / white / pale), and then a code that consists of a specimen identifier (MD #) from the project database and (after the hyphen) a sample identifier from BOLD or from GenBank, followed with its geographic origin.

FIGURES 1 ‒ 6. Views of perching males of species of the subgenus Mendacibombus, showing the anteriorly extended antennae and laterally extended wings that are characteristic of their form of male mate-searching behaviour: 1, B. waltoni at Diebu ca 3910 m, Minshan mountains, Gansu, China, 29. viii. 2009; 2, B. convexus at Diebu ca 3340 m, Minshan mountains, Gansu, China, 29. viii. 2009; 3, B. avinoviellus at Gulmarg ca 2700 m, Pir Panjal mountains, Kashmir, India, 16. viii. 1985; 4, B. himalayanus at Apharwat ca 4100 m, Pir Panjal mountains, Kashmir, India, 30. viii. 1986; 5 ‒ 6, B. margreiteri near Dulan ca 3520 m, Burhan Budai mountains, Qinghai, China, 31. viii. 2010. Photos by PW (Figs 3 – 4 are the best available for these species).

FIGURE 7. Frequency of specimen collection by decade among specimens examined for species of the subgenus Mendacibombus excluding B. mendax and B. handlirschianus.

FIGURE 8. Plot of (y axis) terminal branch lengths from a tree for 43 unique COI haplotypes obtained with BEAST against (x axis) lengths of the barcode sequences in numbers of nucleotides.

FIGURE 9. Map of the global distribution of sites from which samples of the subgenus Mendacibombus have been examined (these bees are unknown from any other regions). Spots are coloured to show the site elevation above sea level (scale in metres to the left). Image showing vegetation, Cartesian orthonormal projection, with north at the top of the map.

FIGURE 10. Plot of (y axis) the number of lineages in the BEAST tree (Fig. 11) of unique COI haplotypes excluding outgroups on a log scale against (x axis) time as substitutions per nucleotide. T, the single threshold at maximum likelihood for the change in branching rate from the GMYC models.

FIGURE 13. Assigning names to species from an estimate of phylogeny for 130 COI sequences of the subgenus Mendacibombus. Based on a BEAST analysis of the 30 unique haplotypes (Fig. 11), with the remaining sequences interpolated back into the tree with 0 branch lengths from their matching samples (where a sequence matches more than one longer sequence within a species in the Collapse results, it is added after the first matching sequence, with the addition of the two short-sequence yellow unbanded specimens from Pakistan, MD # 4058, 4059). The sequence labels follow the format used in Figs 11, 12. Lineages accepted as species from the GMYC models (Fig. 11) are shown as thick branches, the most recent common ancestors of each species are shown with a black spot, and branches within species are shown as thin branches. Asterisks mark samples used as informal proxies for the type specimens of each of the taxon names (Table 1). The proxy sample for the type specimen for the oldest available name (the valid name) for each species (from Fig. 11) is marked in bold. The interpretations of the species with their valid names are shown in grey to the right.