Triepeolus saturninus Cockerell & Sandhouse, 1924

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 : 71-75

Triepeolus saturninus Cockerell & Sandhouse, 1924

Figs 12M , 18C, 28

Triepeolus saturninus Cockerell & Sandhouse, 1924: 312 (♂).

Proposed common name

Saturnine triepeolus.

Diagnosis

The following morphological features in combination tell T. saturninus apart from all other Triepeolus in the simplex species group: the mesopleura have sparse, pale-yellow, erect/suberect, simple setae (reaching about ½ MOD in length) in addition to the usual appressed, branched setae ( Figs 18C , 28A, C ); the legs are extensively dark brown/black from coxae to femora ( Figs 18C , 28A–C ); and the T1 discal patch is trapezoidal ( Fig. 28B ). Triepeolus saturninus most closely resembles T. hirsutus sp. nov. and T. parahirsutus sp. nov., and in all three species the mesopleura have sparse, pale-yellow, erect/ suberect, simple setae (reaching about ½ MOD in length) in addition to the usual appressed, branched setae; the T1 basal band is rather abruptly interrupted medially; and the T1 discal patch is quadrangular, but in T. hirsutus and T. parahirsutus the legs are entirely reddish orange from trochanters to tarsi and the underlying integument of the pseudopygidial area of the female ranges from entirely dark brown/black to predominantly reddish orange whereas in T. saturninus it is entirely dark brown/black ( Fig. 28D ). Additionally, T. saturninus may be confused with T. segregatus or T. shoshone sp. nov. as the ranges of the three species overlap to some extent, but in the latter two species the legs are predominantly to entirely reddish orange from trochanters to tarsi, in T. segregatus the mesopleura laterally do not have erect/suberect, simple setae or have only sparse, short (<¼ MOD), erect/suberect, simple setae in addition to the usual appressed, branched setae, and in T. shoshone the T1 basal band forms an inflexed arch and is thus gradually narrowed but not completely interrupted medially, such that the discal patch has a short, narrowed (i.e., inverted V-shaped) anteromedial projection.

Etymology

The specific epithet was inspired by the shape of the area of black tomentum on T1 (discal patch), which in the original description was said to suggest “the planet Saturn with its rings, only the rings much broader” ( Cockerell & Sandhouse 1924).

Material examined

Primary type material

USA • ♂, holotype; California, Millbrae , San Mateo County; 1 Sep. 1912; E.C. Van Dyke leg.; CAS 1605 .

DNA barcoded material

Unavailable.

Non-barcoded material

USA – California • 1 ♀; Etna , Siskiyou County; 6 Aug. 1978; B. Villegas leg.; UCBME • 1 ♀; Lower Klamath Lake , Siskiyou County; 14 Aug. 1963; J. Schuh leg.; FSCA • 1 ♀; same data as for preceding; 17 Aug. 1963; J. Schuh leg.; FSCA • 1 ♀; Santa Cruz Island (wash N of research station), Santa Barbara County; 22 Oct. 1990; R.W. Thorp leg.; UCBME • 1 ♀; Sunol Regional Wilderness (15 mi E of Fremont ), Alameda County; 24 May 1987; S. Geohegan leg.; USNM . – Idaho • 1 ♀; 3 mi NW of Carey , Blaine County; 8 Aug. 1967; D.S. Horning, Jr. leg.; UCBME . – Oregon • 1 ♀; 6 mi W of Bly , Klamath County; 18 Aug. 1955; W.P. Stephen leg.; OSAC • 1 ♀; ca 5 mi SE of Culver , Jefferson County; 19 Aug. 1984; Schauff and Grissell leg.; USNM • 1 ♀; Dairy , Klamath County; 4 Sep. 1962; J. Schuh leg.; FSCA • 1 ♀; Modoc Point , Klamath County; 14 Aug. 1963; J. Schuh leg.; FSCA • 1 ♀; S of Chiloquin , Klamath County; 13 Aug. 1973; H.V. Weems, Jr. leg.; FSCA . – Utah • 1 ♀; High Creek , Cache County; 15 Aug. 1974; Knowlton and Cazier leg.; BBSL BBSL Faunal Survey No. 000 077 713 . – Washington • 1 ♀; Yakima River Canyon (Hwy 281); 14 Sep. 1990; E. Miliczky leg.; ERM .

Non-preserved material

USA • 1 ♀; Washington, Richland , Benton County; 46.3097° N, 119.2622° W; 1 Sep. 2023; “ janeabel ” obs.; iNaturalist record #185099704 .

Redescription

MEASUREMENTS OF HOLOTYPE. Body length 9.3 mm; ITW 1.9 mm; head length 2.3 mm; head width 3.1 mm; fore wing length 7.5 mm.

Both sexes

INTEGUMENT COLORATION. Dark brown to black except as follows. Mandible with apical half golden yellow and middle quarter in basal half reddish orange. Antenna (except for orange spot basally on F2) dark brown in holotype; scape, pedicel, and F1 extensively orange in some non-type specimens. Tegula, coxae to femora to some extent, and tibiae (excluding metatibial spurs) and tarsi entirely orange. Fore wing membrane dusky subhyaline throughout. Hind wing membrane dusky subhyaline to hyaline.

PUBESCENCE. Face with tomentum densest around antennal socket. Tomentum slightly sparser on clypeus; upper paraocular and frontal areas and vertexal area mostly exposed. Pronotal collar with tomentum uniformly pale yellow. Mesoscutum with well-defined paramedian band of pale-yellow tomentum; pale tomentum otherwise mostly restricted to lateral and posterior margins. Mesopleuron with off-white to pale-yellow, appressed, branched setae; densely setose except for two sparsely setose circular patches (one beneath base of fore wing (hypoepimeral area) and slightly larger one in ventrolateral half of mesopleuron). Mesopleuron with sparse, pale-yellow, erect/suberect, simple setae (reaching about ½ MOD in length) in addition to usual appressed, branched setae. Metanotum with tomentum uninterrupted, uniformly pale yellow. Propodeal triangle mostly glabrous, with (pale) setae restricted to small lateral patches. Metasomal terga with bands of pale-yellow tomentum. T1 with basal and apical transverse bands interrupted medially (former more widely than latter) and subparallel, discal patch trapezoidal. T2–T4 with complete apical transverse bands, that of T2 somewhat narrowed medially and with pair of basomedially convergent anterolateral extensions. S2–S3 with apical transverse bands of white tomentum.

SURFACE SCULPTURE. Labrum coarsely rugose-punctate, with larger punctures than clypeus, but punctures of both equally dense (most i <1d). Clypeus with glabrous midline incomplete and very short, extending from upper margin down to <⅓ length of clypeus. Vertexal area densely punctate (most i ≤ 1d). Mesoscutum, mesoscutellum, and axilla with punctures more or less equally dense (most i≤ 1d); interspaces well defined, shining. Mesopleuron with punctures in upper half nearly contiguous but not much denser (i<1d) than in ventrolateral half (most i ≤ 1d); interspaces shining where punctures not contiguous; punctures similar in size throughout. Discs of metasomal terga with punctures very fine, dense (i ≈1d), and evenly distributed; interspaces shining somewhat.

STRUCTURE. Labrum with pair of small subapical denticles, each preceded by discrete longitudinal ridge. Pronotal collar somewhat elongate (medial length ~ 4/5 MOD). Mesoscutellum weakly bigibbous. Axilla extending little if at all beyond midlength of mesoscutellum; tip distinctly pointed, but mesally unattached to mesoscutellum for less than 2/5 medial length of axilla; lateral margin relatively straight. Fore wing with three submarginal cells.

Female

Paramedian band tapering slightly toward but not attaining anterior margin of mesoscutum. Mesopleuron with black, appressed, branched setae in sparsely setose circular patch in ventrolateral half of mesopleuron. T5 with concave apical margin and large patch of pale-yellow tomentum on each side lateral to pseudopygidial area. Pseudopygidial area with triangular region of posteriorly directed coppery to silvery setae within larger trapezoidal space of posteriorly directed dark brown setae; apical margin with row of dense, suberect, silvery setae. Pygidial plate reddish brown in part and apically truncate. S4 with apical transverse band of white tomentum. S5 straight in lateral view, with apical fimbria of coppery bristle-like setae.

Male

Paramedian band anteriorly joined to lateral transverse band of equally dense pale-yellow tomentum along anterior margin of mesoscutum. T5–T6 with complete apical transverse bands. Pygidial plate with small orange spot subapically, relatively flat and apically rounded. S4–S5 each with apical/subapical fringe of dense, long (> 1 MOD), curved setae, those of S4 coppery to silvery, those of S5 coppery and contrasting with apical transverse bands of white tomentum of preceding sterna.

Distribution

United States west of the Rocky Mountains ( Fig. 12M ).

Ecology

Host records

Unknown.

Floral records

Labels of examined voucher specimens indicate that this species has been collected from the following flowering plant species: in Asteraceae , Chrysothamnus sp. or spp., Grindelia sp. , Machaeranthera canescens (Pursh) A.Gray , and Senecio flaccidus var. douglasii (DC.) B.L.Turner & T.M.Barkley ; and in Fabaceae , Melilotus sp.

Remarks

In the holotype of this species, the discal patch has a Saturn-like shape and thus resembles that of T. joliae Rightmyer, 2008 and, to a lesser extent, some specimens of T. californicus ( Cresson, 1878) . The description of the female of T. saturninus is published here for the first time. Based on known records, adults of T. saturninus are most active from August to September.

Figures

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).

Fig. 18. Mesosoma of female, lateral view. A. Triepeolus hirsutus sp. nov., paratype (AMNH). B. T. paucipunctatus sp. nov., holotype (UCBME M.G.R. Database No. 1216). C. T. saturninus Cockerell & Sandhouse, 1924 (UCBME). D. T. simplex Robertson, 1903 (PCYU). Blue arrows indicate long (≥½ MOD), erect/suberect, simple setae.

Fig. 28. Triepeolus saturninus Cockerell & Sandhouse, 1924. A, D. Female (USNM). A. Habitus, lateral view.B. Female (USNM), habitus, dorsal view. C. Holotype, ♂ (CAS 1605), habitus, lateral view. D. Pseudopygidial area, dorsal view.