Bombus (Pyrobombus) hypnorum ( Linnaeus, 1758 )

Williams, Paul H., Dorji, Phurpa, Ren, Zongxin, Xie, Zhenghua & Orr, Michael, 2022, Bumblebees of the hypnorum-complex world-wide including two new near-cryptic species (Hymenoptera: Apidae), European Journal of Taxonomy 847, pp. 46-72 : 61-62

Bombus (Pyrobombus) hypnorum ( Linnaeus, 1758) s. str.

Figs 1–2 , 17‒26

Apis hypnorum Linnaeus, 1758: 579 . Lectotype by designation of Day (1979): ♀ Sweden ( LSL). Examined.

Bombus calidus Erichson, 1851: 65 . Type not seen, but identity not in doubt.

Diagnosis

Female

Distinguished by the combination: labral tubercle on its broad outer lateral and anterior-facing surface in the centre smooth, with large punctures only along the dorsal and lateral edges; clypeus in the central area with a longitudinal band of small punctures and with very large punctures some spaced by just twice their own diameter; ocello-ocular area along the inner eye margin with a broad band of close small and medium punctures; hair of T4 either white in the posterior half or at least white in a continuous band along the posterior margin; T5 posteriorly in the middle anterior to the smooth posterior margin with a narrow band of large punctures extending for less than an eighth of the length of the tergum.

Male

Distinguished by the combination: hair variable, from the thorax and metasomal T1‒2 hair brown and T3‒4 black, to T1‒4 black.

Material examined

Material sequenced or examined

SWEDEN • 1 ♂; Dalarna, Kopparberg ; 61.979° N, 12.981° E; alt. 614 m; 20 Aug. 2006; P. Williams leg.; BOLD-1550A09 ; PW .

UNITED KINGDOM • 1 ♀ (queen); Buckinghamshire, Whiteleaf ; 51.731° N, 0.816° W; alt. 153 m; 7 Jun. 2008; R. Goodson leg.; BOLD-1550H04 ; PW .

AUSTRIA • 1 ♀ (worker); Tirol, Seefeld ; 47.3227° N, 11.1894° E; alt. 1100 m; 30 Jul. 1972; P. Williams leg.; PW .

NORWAY • 1 ♂; Larvik , Yttersøveien; 59.0615° N, 10.0573° E; alt. 58 m; 14 Jul. 1978; J. Stenløkk leg.; PW .

MONGOLIA • 1 ♀ (worker); Hövsgöl Aymag, Hövsgöl Nuur ; 51° N, 100° E; alt. 2000 m; 18 Jul. 2004; D. Sheppard leg.; BOLD-1550A02 ; PW • 1 ♀ (worker); Hövsgöl Aymag, Hövsgöl Nuur ; 51.05° N, 100.73° E; alt. 1645 m; 20 Jul. 2004; D. Sheppard leg.; BOLD-1550E03 ; PW • 1 ♀ (worker); Hövsgöl Aymag, Hövsgöl Nuur ; 51.05° N, 100.73° E; alt. 1645 m; 24 Jul. 2004; D. Sheppard leg.; BOLD- 1550E02 ; PW • 1 ♀ (worker); Hövsgöl Aymag, Hövsgöl Nuur ; 51.0628° N, 100.7320° E; alt. 1645 m; 28 Jul. 2004; D. Sheppard leg.; BOLD-1550A03 ; PW .

Other selected material sequenced

BOLD: BCZSMHYM01074, BCZSMHYM01075, BIOUG17229E02, BIOUG36732G05.

GenBank: AF279539 , AF279541 , AF279542 , AY181110 , GU674484, GU674503, GU705903 , KJ839370 .

Distribution

The PTP results in Fig. 1 show that the taxon calidus is a part of the species B. hypnorum s. str. and not a separate species, confirming its status as a part of the species, which is treated as a synonym here.

Widespread boreal Palaearctic in the north (from northern Europe to Primorsky, Kamchatka, and Anadyr) and in the south in the temperate mountains of the Pyrenees, Alps, Balkans, Caucasus, and Mongolia, at elevations of 0‒2050 m ( Reinig 1939; Rasmont 1988; Williams 1991; Rasmont et al. 2021).

Figures

Fig. 1. MRBAYES estimate of phylogeny as a metric tree (outgroup B. alpinus (Linnaeus, 1758) not shown) from COI barcodes from GenBank and BOLD databases for the vagans-group and hypnorum- group, with additions from the authors for the hypnorum-group of bumblebees, filtered to remove duplicate and short sequences. Each sequence is labelled with: sequence length; a taxon name from the database; a code consisting of a sequence identifier from the project database and a specimen identifier from the online database; its country and (for larger countries) state or province). The scale bar is calibrated in substitutions per nucleotide site. Results of Bayesian Poisson-tree-process (PTP) models applied for assessing support for species’ gene coalescents by maximum likelihood are shown as PTP scores above the branches: scores approaching 1 and where branches change from blue to red indicates are where the most likely species’ gene coalescents are detected. Asterisks mark sequences used as informal proxies for the type specimens of each of the taxon names in Table 2.

Fig. 2. Distribution of barcoded samples of the hypnorum-complex and B. perplexus Cresson, 1863, with the interpretations as separate candidate species from Fig. 1 shown as different coloured spots as per the colour key on the left. Relief map with hill shading, polar projection (north pole shown as a star), the international boundaries and the Arctic Circle are shown as narrow grey lines, and the northern tree line shown as a broad grey line. Image created in ArcGIS using World_Shaded_Relief basemap (© 2014 Esri).

Figs 3–38. Simplified diagrams for the colour patterns of the hair on the dorsum for ♀♀ (left) and ♂♂ (right) of the Bombus species from Fig. 2. The dorsum is divided into regions, each of which shows only the predominant or most apparent colour for that region using a simplified colour palette (precise shades vary), with olive indicating a mixture of black and yellow hair, and grey indicating a mixture of black and white hair.