Triepeolus Robertson, 1901

Onuferko, Thomas M. & Rightmyer, Molly G., 2024, A revision of the simplex species group of the cleptoparasitic bee genus Triepeolus Robertson, 1901 (Hymenoptera: Apidae), European Journal of Taxonomy 950 (1), pp. 1-106 : 7-18

publication ID	https://doi.org/ 10.5852/ejt.2024.950.2643
publication LSID	lsid:zoobank.org:pub:ACFB8240-3FDC-43B8-8200-236BFE00AD94
DOI	https://doi.org/10.5281/zenodo.13742581
persistent identifier	https://treatment.plazi.org/id/038F531F-FFF3-FFB9-3008-FB86FC44FDED
treatment provided by	Plazi
scientific name	Triepeolus Robertson, 1901
status

Treatment

Genus Triepeolus Robertson, 1901 View in CoL

Diagnosis for the simplex species group within Triepeolus

Females of the presumably monophyletic T. simplex group are easily recognized by the well-defined trapezoidal or triangular pseudopygidial area, which has reflective (golden/coppery to silvery) setae, and concave apical margin of T5 ( Fig. 1 View Fig ; see also photographs in species treatments below, but note the reflective setae are not clearly visible in some images of the pseudopygidial area due to diffused lighting). Females of three other Triepeolus spp. from the Nearctic also have a concave apical margin to T5 but differ in the pseudopygidial area. In two of these— T. dacotensis (Stevens, 1919) and T. mojavensis Linsley, 1939 —the pseudopygidial area has only dark brown/black setae and is poorly differentiated from the rest of T5 ( Fig. 2A View Fig ). The two species are also unusual among Triepeolus in that both lack a well-defined preoccipital carina, which is present at least on the genal area in all other Triepeolus , including the species comprising the T. simplex group. In the third species, T. distinctus ( Cresson, 1878) , the pseudopygidial area of the female has golden to silvery setae but is more or less rectangular in shape ( Fig. 2B View Fig ). Males of the T. simplex group are not easily recognized as no single morphological feature or unique combination of features has been identified that can be considered diagnostic, not in the external morphology or terminalia. Rightmyer (2004) did not find a character state unique to the simplex species group, represented by T. kathrynae Rozen, 1989 , among the 21 morphological characters pertaining to the male S7, S8, or genitalia assessed for 11 markedly different species in the genus. Although several morphological features have been identified as common to males of the T. simplex group, determining conclusively diagnostic features is complicated by the fact that males remain unknown for 31 species of Triepeolus outside the T. simplex and T. verbesinae species groups (see Supp. file 3 for the complete list). In lieu of a diagnosis, a fully illustrated key is presented to enable the identification of males of the T. simplex group among the species of Triepeolus for which the male has been described (i.e., all other species of Triepeolus except those listed in Supp. file 3, for which the key could not be tested).

Key to separate males of the Triepeolus simplex View in CoL group from other Triepeolus View in CoL

1. Any of the following (alone or in combination): clypeus with well-defined glabrous midline, which may extend its entire length ( Fig. 3A View Fig ); F2 shorter than F1 ( Fig. 4A View Fig ); mesoscutellum to some extent reddish brown ( Fig. 5A View Fig ); mesopleuron ventrolaterally with dense, long (≥ ½ MOD), erect/suberect, simple or minutely branched setae ( Fig. 6A View Fig ); propodeal triangle mostly covered in dense, appressed pale setae ( Fig. 7A View Fig ); and/or pygidial plate with well-defined basal or subapical transverse ridge ( Fig. 8A View Fig ) ................................................................... most other Triepeolus spp. (not treated herein)

– The following in combination: clypeus without glabrous midline or rarely with ill-defined glabrous midline restricted to upper half ( Fig. 3B View Fig ); F2 as long as or longer than F1 ( Fig. 4B View Fig ); mesoscutellum black ( Fig. 5B–D View Fig ); mesopleuron ventrolaterally at most with sparse, long (≥ ½ MOD), erect/suberect, simple setae ( Fig. 6B View Fig ) in addition to usual appressed, branched setae or only short (<½ MOD), appressed setae ( Fig. 6C–D View Fig ); propodeal triangle mostly to entirely glabrous, with any pale setae usually restricted to small lateral patches ( Fig. 7B View Fig ); and pygidial plate without transverse ridge or rarely with ill-defined basal transverse ridge ( Fig. 8B View Fig ) .................................................................... 2

2. Pro- and mesotrochanters distinctly tuberculate ( Fig. 9A View Fig ) ................................................................. .................................. T. tuberculifer Onuferko, Rightmyer & Roig-Alsina, 2024 ( T. simplex View in CoL group)

– Pro- and mesotrochanters not tuberculate ( Fig. 9B–D View Fig ) .................................................................... 3

3. Both S4 with apical/subapical fringe of dense, long (> 1 MOD), curved, brown setae and S5 with short, straight subapical setae ( Fig. 10A View Fig ) ................................................ T. simplex Robertson, 1903 View in CoL

– S4 with apical/subapical fringe of dense, long (> 1 MOD), curved, coppery to silvery setae ( Fig. 10B– D View Fig ) and/or S5 with long, curved subapical setae ( Fig. 10C–D View Fig ) ......................................................... 4

4. T1 discal patch trapezoidal with semicircular anteromedial projection, apical transverse band conspicuously narrowed sublaterally at posterior corner of discal patch ( Fig. 11A View Fig ). Axilla extending well beyond midlength of mesoscutellum; tip distinctly pointed and hooked (i.e., concave along medial margin), mesally unattached to mesoscutellum for approximately half medial length of axilla ( Fig. 5B View Fig ) [ The Bahamas and Cuba View in CoL ] ..................................... T. roni Genaro, 1999 View in CoL ( T. simplex View in CoL group)

– Mesosoma and metasoma without the combination of features listed above [other regions] .......... 5

5. T1 with basal band of pale tomentum arched, on each side (or each if medially interrupted) continuous with (and indistinguishable from) lateral longitudinal band, such that discal patch triangular, semicircular, or crescent-shaped ( Fig. 11B–C View Fig ) ................................................................................. 6

– Not as above. T1 basal and apical transverse bands (if present, distinct, and joined laterally) with abrupt transition between basal band and lateral longitudinal band ( Fig. 11D–E View Fig ) (at least if transverse bands not effectively mirror images, as in Fig. 11F–H View Fig ), such that discal patch quadrangular or transversely oblong or elliptic ( Fig. 11D–H View Fig ) .................................................................................... 7

6. Any of the following (alone or in combination): T1 discal patch forming trapezoid or triangle with concave or straight anterolateral sides (basal/lateral band (or patch) of off-white to yellow tomentum on each side (or each) mesally convex or straight) ( Fig. 11B View Fig ); T1–T4 with medially interrupted apical transverse bands ( Fig. 11B View Fig ); and/or S3 with long, curved subapical setae ( Fig. 10C View Fig ) ............ ............................................................................................ other Triepeolus spp. (not treated herein)

– The following in combination: T1 discal patch semicircular or crescent-shaped (basal/lateral band (or patch) of yellow tomentum on each side (or each) mesally concave) ( Fig. 11C View Fig ); T3–T4 and usually also T2 with complete apical transverse bands ( Fig. 11C View Fig ); and S3 with short, straight subapical setae ( Fig. 10D View Fig ) ................................................................................................................. T. simplex View in CoL group

7. The following in combination: legs to some extent orange ( Figs 3B View Fig , 6B View Fig , 9B–D View Fig , 11E View Fig ); axilla with tip acute and distinctly pointed ( Fig. 5C View Fig ); T1 basal band distinctly interrupted medially or notched posteromedially ( Fig. 11E View Fig ); T2 with complete or medially narrowly interrupted apical transverse band with pair of basomedially strongly convergent anterolateral extensions (except sometimes in T. rhododontus Cockerell, 1921 View in CoL ) ( Fig. 11E View Fig ); and T3–T4 with complete apical transverse bands ( Fig. 11E View Fig ) .................................................................................................................. T. simplex View in CoL group

– Any of the following (alone or in combination): legs entirely dark brown/black ( Fig. 11F–G View Fig ); axilla with tip right angled or obtuse and somewhat blunt if not broadly rounded ( Fig. 5D View Fig ); T1 basal band (if present) not distinctly interrupted medially or notched posteromedially ( Fig. 11G View Fig ); T2–T4 apical transverse bands (if present) interrupted medially ( Fig. 11F View Fig ); and/or that of T2 (if present) without anterolateral extensions ( Fig. 11H View Fig ) or with pair of basomedially weakly convergent, perpendicular, or basolaterally divergent anterolateral extensions ( Fig. 11F–G View Fig ) ..................................................... 8

8. Any of the following (alone or in combination): legs entirely dark brown/black ( Fig. 11F–G View Fig ); mesopleuron densely punctate (i ≤1d) ( Fig. 6C View Fig ); T1 basal ( Fig. 11G View Fig ) and/or apical ( Fig. 11G–H View Fig ) transverse bands (if present) complete; T2–T4 with medially interrupted apical transverse bands ( Fig. 11F View Fig ); and/or that of T2 with pair of well-defined anterolateral extensions ( Fig. 11F–G View Fig ) .......... ............................................................................................ other Triepeolus spp. (not treated herein)

– The following in combination: legs to some extent orange ( Figs 6D View Fig , 10D View Fig , 11C–D View Fig ); mesopleuron somewhat sparsely punctate (i≤ 3d) ( Fig. 6D View Fig ); T1 with medially interrupted basal and apical transverse bands ( Fig. 11D View Fig ); T2 with complete ( Fig. 11C View Fig ) or medially narrowly interrupted ( Fig. 11D View Fig ) apical transverse band without well-defined anterolateral extensions; T3–T4 with complete apical transverse bands ( Fig. 11C–D View Fig ) ................................................................................. T. simplex View in CoL group