Leptocera erratica Buck, 2009

Buck, Matthias & Marshall, Stephen A., 2009, Revision of New World Leptocera Olivier (Diptera, Sphaeroceridae), Zootaxa 2039 (1), pp. 1-139 : 32-34

Leptocera erratica Buck , new species

( Figs. 55–61 , 141 )

Description. Body length 2.1–2.7 mm. Coloration similar to L. caenosa , with pale elements usually slightly more developed: Medium brown with anterior part of frons, lower part of face (sometimes), inner surfaces of pedicel and first flagellomere and part of gena more or less yellow to reddish; palpus, inner surface of fore coxa, mid trochanter, knees, apices of tibiae, base of fore tibia and tarsi pale brown. Uppermost orbital setula inclinate and proclinate (sometimes absent on one side). Arista long-pubescent (as in L. caenosa ). Palpus inflated (even slightly more than in L. caenosa ), ca. 3.5x as long as wide. Mid tibia with bristle above distal dorsal about 0.4–0.6x as long as distal anterodorsal bristle; lowermost bristle of proximal posterodorsal series shorter than lowermost bristle of anterodorsal series; posteroapical bristles short and usually of equal length, ventral one sometimes longer. Segments 3–5 of fore tarsus dilated in male, normal in female.

Male terminalia ( Figs. 55–58 ): Sternite 5 with few long bristles posterolaterally; posteromedial field of microtrichia fairly narrow, subtriangular; hind margin with short and very fine, hair-like scales (somewhat overemphasized in Fig. 58 ). Epandrium with relatively few long bristles ventrally. Anterior section of surstylus with anterior process extending far ventrally, laterally with a subtle ridge terminating in a darker, preapical, anteriorly directed point; ventral lobe nearly flat and almost bristleless, its long posterior bristle shifted forward and greatly removed from hind margin. Posterior section of surstylus of roughly triangular shape (posterior view), inner margin only very narrowly desclerotized (unlike most South American species), apex with two strong bristles (both with pointed tips), posterior surface with few long pale hairs in lateral half. Cercus simple (i.e., without finger-like or lamellate medial process). Postgonite with wide and shallow posterobasal notch ( Fig. 141 ).

Female terminalia ( Figs. 59–61 ): Tergite 7 moderately long and convex (length smaller than in South American species), with a pair of strong, cruciate bristles near middle, apparently tomentose throughout and lacking shining areas. Sternite 7 with simple hind margin. Fused tergite 10 + cerci moderately short (longer than in South American species), with short hairs. Spermathecae elongate, with transversely ridged basal half and slightly dilated, bumpy distal half.

Type material. Holotype ♂ ( ANIC) and 4 ♂♂ and 1 ♀ paratypes ( DEBU): AUSTRALIA, Queensland, Mt. Glorious, 27.iv–26.x.1989, malaise, A. Hiller. Other paratypes: U.S.A. California: 3 ♂♂, 2 ♀♀, Kern Co., nr. Buttonwillow, 15.vi.1961, C.W. O'Brien ( EMEC); 1 ♂, San Diego Co. , Borrego, 24.iv.1949, at light, L.W. Quate ( EMEC). ARGENTINA. Prov. Salta: 1 ♂, Rosario de Lerma , 24.ii.1992, swept over foul ditch, S.A. Marshall ( DEBU). SOUTH AFRICA. Natal: 1 ♂, 75 km WSW Estcourt Cathedral Peaks For. Stn., 1,500 m, 7–31.xii.1979, dung trap, S. & J. Peck ( DEBU).

Other material examined (unassociated females). ARGENTINA. Prov. Entre Ríos: 1 ♀, Río Paraná Ibicuy, Puerto Ibicuy , 10.xii.1979, C.M. & O.S. Flint ( USNM). Prov. Santa Fé: 1 ♀, 26 km S Reconquista Rt. 11.2 km NE Berna, 20–21.ii.1980, pig dung traps, R.E. Woodruff ( DEBU). Note: females cannot be separated from L. caenosa with certainty .

Etymology. The species is named for its erratic occurrence on four different continents.

Distribution. U.S.A. (California, Map 1), Argentina, Australia (Queensland) and South Africa (Natal). The distribution pattern of this species poses an interesting biogeographic problem. We suspect that the population in southern California is due to accidental introduction. It is remarkable that the species appears to be very rare in South America, the biogeographic origin of the L. caenosa group.

Discussion. Obviously related to L. caenosa , the only other species with inflated palpus. Nevertheless, the male terminalia of L. erratica sp.n. are very distinct and differ markedly from L. caenosa . Diagnostic are the small field of enlarged microtrichia of male sternite 5, the very short and inconspicuous hair-like marginal scales of male sternite 5, and the triangular posterior section of the surstylus with two pointed apical bristles. Unfortunately, females cannot be reliably separated from L. caenosa because the shining medial stripe of tergite 7 is not always present in the latter.

Figures

FIGURES 55–61. Leptocera erratica sp.n. (55–57: Argentina, 58: Australia, 59–61: U.S.A.). Male terminalia (phallus and postgonites omitted): (55) lateral; (56) posterior; (57) ventral; (58) sternite 5. Female terminalia: (59) dorsal; (60) spermathecae; (61) ventral.

FIGURES 138–146. Postgonites and aedeagal complex of Leptocera caenosa group. Postgonites of (138) L. aequilimbata (Argentina), (139) L. argentinica sp.n. (Argentina), (140) L. neocurvinervis (Chile), (141) L. erratica sp.n. (South Africa), (142) L. sphaerotheca sp.n. (U.S.A.), (143) L. ellipsipennis (Juan Fernández Is.), (144) L. parallelipennis sp.n. (Juan Fernández Is.), (145) L. cultellipennis (Juan Fernández Is.). Aedeagal complex of (146) L. duplicata (Juan Fernández Is.). bp—basiphallus, dp—distiphallus, ea—ejaculatory apodeme, pa—phallapodeme, pg—postgonites.