Orasema scaura, Baker & Heraty, 2020

Baker, Austin J. & Heraty, John M., 2020, The New World ant parasitoid genus Orasema (Hymenoptera: Eucharitidae), Zootaxa 4888 (1), pp. 1-84 : 18-20

Orasema scaura n. sp.

urn:lsid:zoobank.org:act:D2243AD5-BA0B-4A9C-B82D-4C7CCB2D3B89

( Fig. 9 )

Diagnosis. Distinguished from other members of the coloradensis group by having all tarsi with four segments,

tarsomeres distinctly lobate with lobes broadly overlapping subsequent tarsomeres on the ventral side ( Fig. 9E ), and antennal flagellum length shorter than height of the head ( Fig. 9B ). This is the only eucharitid known to have 4-segmented tarsi.

Description. Female. Length 3.0– 3.4 mm ( Fig. 9A ). Color. Head and mesosoma iridescent blue-green. Scape, pedicel, anellus, and flagellum brown. Coxae iridescent blue-green; femora mostly brown with iridescence, tips pale; tibiae yellow. Gaster same as mesosoma. Head ( Fig. 9B ). HW:HH = 1.2–1.3; face imbricate; eyes sparsely se-tose, IOD:EH = 1.4–1.6; MS:EH = 0.7–0.9; supraclypeal area slightly broader than long, weakly sculptured. Labrum with variably asymmetric digits with 4–9 setae ( Fig. 9F ). Occiput with dorsal margin rounded. Pedicel globose, not as broad as F1. FL:HH = 0.8–1.0; F2L:F2W = 1.1–1.4, F2L:F3L = 1.3–1.8 ( Fig. 9D ). Mesosoma ( Fig. 9C, G ). ML: MH = 1.3–1.6. Mesoscutal midlobe imbricate, densely setose; lateral lobe smooth. Axilla smooth, dorsally rounded, on roughly same plane as mesoscutellum; scutoscutellar sulcus narrow, regularly foveate, broadly separated from transscutal articulation; mesoscutellar disc smooth; frenal line irregularly foveate; frenum smooth; axillular sulcus distinct and foveate; axillula areolate-reticulate. Propodeal disc broadly rounded, with shallow medial depression, rugose-areolate ( Fig. 9H ); callus nearly smooth, densely setose. Propleuron imbricate. Prepectus weakly rugose. Mesepisternum reticulate laterally, smooth ventrally. Upper and lower mesepimeron smooth; transepimeral sulcus weakly impressed. Metepisternum laterally smooth. HCL:HCW = 1.4–2.0, with weak dorsolateral sculpture; HFL: HFW = 3.1–3.8. FWL:FWW = 2.2–2.5, FWL:ML = 1.8–2.1; submarginal vein with several long setae; postmarginal vein slightly longer than stigmal vein. Metasoma. Petiole cylindrical, linear in profile, PTL:PTW = 1.2–1.6, PTL: HCL = 0.7–0.9, areolate-reticulate, lateral margin rounded, ventral sulcus present. First (ventral) valvula with 6–8 small, narrowly separated teeth, second (dorsal) valvula with 6 or 7 annuli that are narrowly separated dorsally, the carinae coalescing.

Male. Unknown.

Hosts. Unknown.

Plant associates. Swept from Ericameria nauseosa (Asteraceae) in Idaho.

Distribution ( Fig. 5 ). United States: AZ, CA, ID, NV. Collected June–August.

Material examined. Holotype. UNITED STATES. Idaho: Butte Co., 6 mi S Howe, 43°42’0”N, 113°01’50”W, 28.vii-4.viii.1983, M.P. Stafford, host plant: Ericameria nauseosa [♀, deposited in WFBM: UCRCENT00407525].

Paratypes. UNITED STATES. Arizona: Cochise Co., Cave Ck. Cyn. Chiricahua Mts, 6 mi W Portal, 2042m, 31°55’0”N, 109°15’0”W, 11.vii.1981, H.A. Hespenheide [1♀, UCLA: UCRCENT00414825]. Coconino Co., Hwy 180 SE Valle, 1850m, 35°37’13”N, 112°05’45”W, 26.vii.2008, S. Triapitsyn [1♀, UCRC: UCRCENT00264701]. Amedee, 40 ° 16’12”N, 120 ° 09’36”W, 4.vii.1947, T.F. Leigh [1♀, EMEC: UCRCENT00236340]. California: Lassen Co., Hallelujah Junction, 1440m, 39°47’0”N, 120°04’0”W, 1-3.vii.1992, D. Carmean, 73 [1♀, UCDC: UCRCENT00416100]. Hallelujah Junction, 1440m, 39°47’0”N, 120°04’0”W, 29-30.vi.2006, M.F. Sherriffs, 060 [1♀, UCDC: UCRCENT00477664]. Idaho: Butte Co., 6 mi S Howe, 43 ° 42’0”N, 113 ° 01’50”W, 28.vii-4.viii.1983, M.P. Stafford, host plant: Ericameria nauseosa [45♀, WFBM: UCRCENT00403564–75, UCRCENT00403577– 78, UCRCENT00403581–82, UCRCENT00403585, UCRCENT00407501–02, UCRCENT00407504–12, UCRCENT00407514–20, UCRCENT00407522–24, UCRCENT00407526–28, UCRCENT00407531, UCRCENT00407533–34, UCRCENT00407537]. 6 mi. S Howe, 43 ° 41’24”N, 113 ° 01’48”W, 4.viii.1983, N.P Stafford [1♀, WFBM: UCRCENT00003619]; 22.vii.1982, J.B. Johnson, host plant: Ericameria nauseosa [5♀, WFBM: UCRCENT00403576, UCRCENT00403583, UCRCENT00403604, UCRCENT00407521, UCRCENT00407561] Canyon Co., 15 mi S Nampa, 43 ° 18’47”N, 116 ° 6’11”W, 21.vi.1977, J.M. Domek [1♀, WFBM: UCRCENT00403580]. Cassia Co. , 9 mi E Malta, 42 ° 18’25”N, 113 ° 11’28”W, 14.vii.1981, R.P. Wight [1♀, WFBM: UCRCENT00403584]. Nez Perce Co., Hells Gate St. Pk., 293m, 46°21’24”N, 117°03’3”W, 14.vii.1983, J.B. Johnson, host plant: Ericameria nauseosa [3♀, WFBM: UCRCENT00407478, UCRCENT00407494–95]. Twin Falls Co., Rogerson, 42 ° 13’5”N, 114 ° 35’38”W, 20.vii.1961, R.E. Stecker, host plant: Chrysothamnus [1♀, WFBM: UCRCENT00403579]. Nevada: Carson City, 39 ° 09’49”N, 119 ° 46’3”W, 6.vii, Baker [6♀, USNM: UCRCENT00247968–70, UCRCENT00248316–18]. Nye Co., Mercury, 36 ° 39’39”N, 115 ° 59’40”W, 5.viii.1964 [2♀, USNM: UCRCENT00248383–84]. Washoe Co., S end of Pyramid Lake, 1140m, 39 ° 50’35”N, 119 ° 26’49”W, 8.vii.1982, D.E. Russell [2♀, UCDC: UCRCENT00404586, UCRCENT00404588]; L.D. French [2♀, UCDC: UCRCENT00404585, UCRCENT00404587]; P.Timper [2♀, UCDC:UCRCENT00404583, UCRCENT00416064]. Verdi, 39 ° 31’5”N, 119 ° 59’20”W, 12.vii.1974, B. Villegas [1♀, UCDC: UCRCENT00404584].

Etymology. Latin, meaning “swollen ankles,” which refers to the thick, lobate tarsomeres.

Discussion. Because the comparatively large number of specimens collected for this species (75 examined) are all female, it seems likely that this species is parthenogenetic. Attempts to sequence Wolbachia from two pointmounted specimens collected in 1983 and 2008 were negative.

Figures

FIGURE 5. Distribution map of species in the Orasema coloradensis species group.

FIGURE 9. Orasema scaura. Holotype female (UCRCENT00407525): A, habitus, lateral; B, head, anterior; C, mesosoma, lateral; D, antenna; G, mesosoma, dorsal; H, propodeum, posterior. Female (UCRCENT00407508): E, tarsus. Paratype female (UCRCENT00407506): F, labrum.