A revision of the simplex species group of the cleptoparasitic bee genus Triepeolus Robertson, 1901 (Hymenoptera: Apidae) Author Onuferko, Thomas M. 6E4CC25A-AD82-42D3-9846-C659EDEAF541 Canadian Museum of Nature, P. O. Box 3443, Station D, Ottawa, ON K 1 P 6 P 4, Canada and University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M 1 C 1 A 4, Canada. thomas.onuferko@gmail.com Author Rightmyer, Molly G. 90A04B61-0B07-4F3F-8F9E-DDCBDC108314 Department of Entomology, San Diego Natural History Museum, 1788 El Prado, San Diego, CA 92101, USA. molly_rightmyer@yahoo.com text European Journal of Taxonomy 2024 2024-09-02 950 1 1 106 https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2643/12195 journal article 302884 10.5852/ejt.2024.950.2643 81037ee2-a646-42f0-beb2-c315dec5320c 2118-9773 13691805 ACFB8240-3FDC-43B8-8200-236BFE00AD94 Genus Triepeolus Robertson, 1901 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 ; 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 ). 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 ). 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 group from other Triepeolus 1. Any of the following (alone or in combination): clypeus with well-defined glabrous midline, which may extend its entire length ( Fig. 3A ); F2 shorter than F1 ( Fig. 4A ); mesoscutellum to some extent reddish brown ( Fig. 5A ); mesopleuron ventrolaterally with dense, long (≥ ½ MOD), erect/suberect, simple or minutely branched setae ( Fig. 6A ); propodeal triangle mostly covered in dense, appressed pale setae ( Fig. 7A ); and/or pygidial plate with well-defined basal or subapical transverse ridge ( Fig. 8A ) ................................................................... 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 ); F2 as long as or longer than F1 ( Fig. 4B ); mesoscutellum black ( Fig. 5B–D ); mesopleuron ventrolaterally at most with sparse, long (≥ ½ MOD), erect/suberect, simple setae ( Fig. 6B ) in addition to usual appressed, branched setae or only short (<½ MOD), appressed setae ( Fig. 6C–D ); propodeal triangle mostly to entirely glabrous, with any pale setae usually restricted to small lateral patches ( Fig. 7B ); and pygidial plate without transverse ridge or rarely with ill-defined basal transverse ridge ( Fig. 8B ) .................................................................... 2 Fig. 2. Pseudopygidial area of female, dorsal view. A . Triepeolus dacotensis (Stevens, 1919) (BOLD sample ID: CCDB-32640 E03; RSKM RSKM_ENT_E-186200). B . T. distinctus ( Cresson, 1878 ) (OKBS OKBS.POL.314). Fig. 3. Head of male, frontal view. A . Triepeolus michiganensis Mitchell, 1962 (CNC 719805), which has a strong glabrous clypeal midline (blue arrow). B . T. obliteratus Graenicher, 1911 (WRME WRME_ EJH02370), which does not have a glabrous clypeal midline. Fig. 4. Right antenna (basal portion) of male. A . Triepeolus loomisorum Rozen, 1989 (PCYU), showing the longer side of F1 noticeably longer than F2. B . T. oblongimacula sp. nov. , allotype (BOLD sample ID: CMNTO_298; PCYU PCYU-SD09:28), showing the longer side of F1 and F2 subequal in length. Blue lines indicate the greatest length of F1. Fig. 5. Axillae and mesoscutellum of male, dorsal view. A . Triepeolus intrepidus (Smith, 1879) (PCYU PCYU-SD09:612). B . T. roni Genaro, 1999 (USNM M.G.R. Database No. 5922). C . T. hirsutus sp. nov. , allotype (PCYU). D . T. brittaini Cockerell, 1931 (BOLD sample ID: 05-NS-0718; PCYU). Fig. 6. Mesosoma of male, lateral view. A . Triepeolus melanarius Rightmyer, 2008 (CSUC), which ventrolaterally has dense, long (≥ ½ MOD), erect/suberect, minutely branched setae (blue arrow). B . T. parahirsutus sp. nov. , allotype (ZMB 21261), which ventrolaterally has sparse, long (≥ ½ MOD), erect/suberect, simple setae among the usual appressed, branched setae (blue arrow). C . T. joliae Rightmyer, 2008 (CNC 1801918). D . T. eumeniformis sp. nov. , paratype (ECOSUR ECO-TA-E-41271), which does not have dense, long (≥ ½ MOD), erect/suberect setae. Fig. 7. Mesosoma of male, posterior view. A . Triepeolus eliseae Rightmyer, 2017 (INHS 356997), in which the propodeal triangle is mostly covered in dense, appressed pale setae. B . T. obliteratus Graenicher, 1911 (WRME WRME_EJH02370), in which the propodeal triangle is mostly to entirely glabrous. Fig. 8. Pygidial plate of male, dorsal view. A . Triepeolus rufithorax Graenicher, 1928 (PCYU), which has a well-defined transverse ridge (blue arrow). B . T. oblongimacula sp. nov. , allotype (BOLD sample ID: CMNTO_298; PCYU PCYU-SD09:28), which does not have a transverse ridge. Fig. 9. Right pro- and mesotrochanters of male (anterior facing right). A . Triepeolus tuberculifer Onuferko, Rightmyer & Roig-Alsina, 2024 , allotype (FSCA M.G.R. Database No. 3704), showing distinct protuberances (blue arrows). B . T. obliteratus Graenicher, 1911 (WRME WRME_EJH02370). C . T. oblongimacula sp. nov. , allotype (BOLD sample ID: CMNTO_298; PCYU PCYU-SD09:28). D . T. rhododontus Cockerell, 1921 (BOLD sample ID: CMNTO_139; PCYU). 2. Pro- and mesotrochanters distinctly tuberculate ( Fig. 9A ) ................................................................. .................................. T. tuberculifer Onuferko, Rightmyer & Roig-Alsina, 2024 ( T. simplex group) – Pro- and mesotrochanters not tuberculate ( Fig. 9B–D ) .................................................................... 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 ) ................................................ T. simplex Robertson, 1903 – S4 with apical/subapical fringe of dense, long (> 1 MOD), curved, coppery to silvery setae ( Fig. 10B– D ) and/or S5 with long, curved subapical setae ( Fig. 10C–D ) ......................................................... 4 4. T1 discal patch trapezoidal with semicircular anteromedial projection, apical transverse band conspicuously narrowed sublaterally at posterior corner of discal patch ( Fig. 11A ). 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 ) [ The Bahamas and Cuba ] ..................................... T. roni Genaro, 1999 ( T. simplex group) – Mesosoma and metasoma without the combination of features listed above [other regions] .......... 5 Fig. 10. Metasoma of male, lateral view. A . Triepeolus simplex Robertson, 1903 (BOLD sample ID: QUBS0291G11; PCYU) showing S4 with apical/subapical fringe of dense, long (>1 MOD), curved setae (blue arrow). B . T. diffusus Rightmyer, 2008 (RAM pmae00146019) showing S4 with apical/ subapical fringe of dense, long (> 1 MOD), curved setae (blue arrow). C . T. rufoclypeus (Fox, 1891) (PCYU) showing S3–S5 each with apical/subapical fringe of dense, long (>1 MOD), curved setae (blue arrows). D . T. eumeniformis sp. nov. , paratype (ECOSUR ECO-TA-E-41271) showing S4–S5 each with apical/subapical fringe of dense, long (> 1 MOD), curved setae (blue arrows). 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 ) ................................................................................. 6 Fig. 11A–F (continued on next page). Metasoma of male, dorsal view. A . Triepeolus roni Genaro, 1999 (USNM M.G.R. Database No. 5922). B . T. buchwaldi (Friese, 1908) (INHS 387483). C . T. eumeniformis sp. nov. , paratype (ECOSUR ECO-TA-E-41271). D . T. eumeniformis sp. nov. , paratype (CNC 1801914). E . T. kathrynae Rozen, 1989 (RSKM RSKM_ENT_E-168244). F . T. tristis (Smith, 1854) (BOLD sample ID: CCDB-30345 C09; PCYU). Blue lines indicate an abrupt (A, D–E) or seamless (B–C) transition between the basal band and lateral longitudinal band. Fig. 11G–H (continued). Metasoma of male, dorsal view. G . Triepeolus paenepectoralis Viereck, 1905 (CNC 719831). H . T. distinctus ( Cresson, 1878 ) (OKBS OKBS.POL.488). – 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 ) (at least if transverse bands not effectively mirror images, as in Fig. 11F–H ), such that discal patch quadrangular or transversely oblong or elliptic ( Fig. 11D–H ) .................................................................................... 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 ); T1–T4 with medially interrupted apical transverse bands ( Fig. 11B ); and/or S3 with long, curved subapical setae ( Fig. 10C ) ............ ............................................................................................ 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 ); T3–T4 and usually also T2 with complete apical transverse bands ( Fig. 11C ); and S3 with short, straight subapical setae ( Fig. 10D ) ................................................................................................................. T. simplex group 7. The following in combination: legs to some extent orange ( Figs 3B , 6B , 9B–D , 11E ); axilla with tip acute and distinctly pointed ( Fig. 5C ); T1 basal band distinctly interrupted medially or notched posteromedially ( Fig. 11E ); 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 ) ( Fig. 11E ); and T3–T4 with complete apical transverse bands ( Fig. 11E ) .................................................................................................................. T. simplex group – Any of the following (alone or in combination): legs entirely dark brown/black ( Fig. 11F–G ); axilla with tip right angled or obtuse and somewhat blunt if not broadly rounded ( Fig. 5D ); T1 basal band (if present) not distinctly interrupted medially or notched posteromedially ( Fig. 11G ); T2–T4 apical transverse bands (if present) interrupted medially ( Fig. 11F ); and/or that of T2 (if present) without anterolateral extensions ( Fig. 11H ) or with pair of basomedially weakly convergent, perpendicular, or basolaterally divergent anterolateral extensions ( Fig. 11F–G ) ..................................................... 8 8. Any of the following (alone or in combination): legs entirely dark brown/black ( Fig. 11F–G ); mesopleuron densely punctate (i ≤1d) ( Fig. 6C ); T1 basal ( Fig. 11G ) and/or apical ( Fig. 11G–H ) transverse bands (if present) complete; T2–T4 with medially interrupted apical transverse bands ( Fig. 11F ); and/or that of T2 with pair of well-defined anterolateral extensions ( Fig. 11F–G ) .......... ............................................................................................ other Triepeolus spp. (not treated herein) – The following in combination: legs to some extent orange ( Figs 6D , 10D , 11C–D ); mesopleuron somewhat sparsely punctate (i≤ 3d) ( Fig. 6D ); T1 with medially interrupted basal and apical transverse bands ( Fig. 11D ); T2 with complete ( Fig. 11C ) or medially narrowly interrupted ( Fig. 11D ) apical transverse band without well-defined anterolateral extensions; T3–T4 with complete apical transverse bands ( Fig. 11C–D ) ................................................................................. T. simplex group Distribution of the Triepeolus simplex group Canada ( Ontario to British Columbia ) to central Argentina including the Antilles ( Fig. 12A ). Fig. 12A–D (continued on next page). Distribution maps. A . All species in the Triepeolus simplex group. B . T. apache sp. nov. C . T. eumeniformis sp. nov. D . T. hirsutus sp. nov. Approximate geographic ranges are indicated in orange and were estimated from occurrence records known to the authors (yellow and blue circles, with the latter indicating localities of DNA barcoded specimens). Included species Triepeolus alvarengai Moure, 1955 Triepeolus apache sp. nov. Triepeolus eumeniformis sp. nov. Triepeolus hirsutus sp. nov. Triepeolus kathrynae Rozen, 1989 Triepeolus mexicanus ( Cresson, 1878 ) Fig. 12E–H (continued from preceding and on next page). Distribution maps. E . Triepeolus kathrynae Rozen, 1989 . F . T. mexicanus ( Cresson, 1878 ) . G . T. obliteratus Graenicher, 1911 . H . T. oblongimacula sp. nov. Approximate geographic ranges are indicated in orange and were estimated from occurrence records known to the authors (yellow and blue circles, with the latter indicating localities of DNA barcoded specimens). Included species (continued) Triepeolus nemoralis ( Holmberg, 1886 ) Triepeolus obliteratus Graenicher, 1911 Triepeolus oblongimacula sp. nov. Triepeolus parahirsutus sp. nov. Triepeolus paucipunctatus sp. nov. Triepeolus rhododontus Cockerell, 1921 Included species (continued) Fig. 12I–L (continued from preceding and on next page). Distribution maps. I . Triepeolus parahirsutus sp. nov. J . T. paucipunctatus sp. nov. K . T. rhododontus Cockerell, 1921 . L . T. roni Genaro, 1999 . Approximate geographic ranges are indicated in orange and were estimated from occurrence records known to the authors (yellow and blue circles, with the latter indicating localities of DNA barcoded specimens). Triepeolus roni Genaro, 1999 Triepeolus saturninus Cockerell & Sandhouse, 1924 Triepeolus segregatus ( Cockerell, 1900 ) Triepeolus shoshone sp. nov. Triepeolus simplex Robertson, 1903 Triepeolus tuberculifer Onuferko, Rightmyer & Roig-Alsina, 2024