Leptocera neovomerata Buck, 2009

Buck, Matthias & Marshall, Stephen A., 2009, Revision of New World Leptocera Olivier (Diptera, Sphaeroceridae), Zootaxa 2039 (1), pp. 1-139 : 87-89

Leptocera neovomerata Buck , new species

(Figs. 177–184, 204)

Leptocera finalis auctt., nec ( Collin, 1956): Marshall, 1997 (in part).

Leptocera vomerata auctt., nec Roháček & Papp, 1983: Buck in Roháček et al., 2001 (in part: Nearctic records).

Description. Outstanding paramedian acrostichals not very enlarged, longest one at most 0.75x as long as lower orbital bristle (usually only about half as long); prescutellar acrostichals only slightly enlarged. Mid tibia with bristle above distal dorsal clearly longer than (ca. 1.2–1.8x as long as) anteroapical bristles, also distinctly longer than corresponding bristle above distal anterodorsal; posteroapical bristles subequal and relatively long, extending at least to socket of ventrobasal bristle of metatarsus.

Male terminalia (Figs. 177–180): Sternite 5 with posteromedial desclerotized relatively narrow but deep (subtriangular; similar to L. vomerata ), not unusually haired like L. fontinalis . Anterior section of surstylus with anterior process in lateral view relatively short and more or less pointed apically (not distinctly widened subapically like L. vomerata ); ventral lobe with a longitudinal notch near posterior end, portion in front of notch not very prominent, rounded, gradually rising from notch, with bristles of intermediate length; inner ridge adjacent to notch with two bristles. Apex of anterior process without prominent, bare, darker, lateral ridge (ventral view). Posterior section of surstylus with bristles of dorsal (posterior) surface restricted to basal half, numerous (as in L. vomerata , fewer than in L. fontinalis ); the two strong apical bristles subequal. Postgonite as in Fig. 204 , with relatively wide posterior notch as in L. vomerata .

Female terminalia (Figs. 181–184) similar to L. fontinalis: Hind margin of sternite 7 straight, median 2/5 with edge narrowly bare (devoid of microtrichia), well sclerotized and usually slightly darker; sternite therefore appearing sharp-edged in undissected specimens (in other species except L. fontinalis hind margin gradually desclerotized, evenly microtrichose and therefore ill-defined). Sternite 8 with lateral margins almost straight, posterolateral lobes very long, triangular, pointed to somewhat blunt apically; median process rounded and wide. Spermathecae subcylindrical (single one) to slightly pear-shaped (paired ones), spicules fairly evenly distributed (not more numerous towards base or apex); apex with well-developed invagination, base laterally with similar depression (in paired spermathecae located on side facing other spermatheca); surface with very fine striation.

Type material. Holotype ♂ ( DEBU): U.S.A., New Mexico, Lincoln Co., Sierra Blanca , 9,700 ft, 10–26.vi.1976, spruce / fir by stream, malaise, S. & J. Peck . Paratypes: 1 ♀, same as holotype except 10–26.vi.1979, spruce / birch [a]long stream, malaise ( USNM). CANADA. Yukon Territory : 1 ♂, Tombstone Mts. , 3.vii.1985, river gravel, flood debris, S.A. Marshall ( DEBU) ; 1 ♂, North Fork Crossing mi 42 Peel Plt. Rd. , 3,500 ft, 25.vi.1962, R.E. Leech ( CNCI) ; 1 ♀, Dempster Hwy km 141, Blackstone River , 6–11.vii.1985, fishhead trap along river, S.A. Marshall ( DEBU). U.S.A. Alaska : 1 ♂, 1 ♀, Richardson Hwy mi 206, 19.vi.1987, beaver pond, debris nr. pond, S.A. Marshall ( DEBU). Colorado : 1 ♂, Boulder Co., Corona Pass, 10,600 ft, 9.vii.1961, timberline, marshy meadow, J.G. Chillcott ( CNCI). Wyoming : 1 ♂, Sheridan Co., 20.3 km W of Burgess Jct., Antelope Butte Recr. Area , pans along stream, cow manure, J.E. Swann ( DEBU) .

FIGURES 177–184. Leptocera neovomerata sp.n. (177–180, 183: U.S.A., 181–182, 184: Canada). Male terminalia (phallus and postgonites omitted): (177) lateral; (178) posterior; (179) ventral; (180) sternite 5. Female terminalia: (181) dorsal; (182) spermathecae; (183) ventral, for sternite 8 see following Fig.; (184) sternite 8.

Etymology. The name refers to the fact that this is the Nearctic sister species to the eastern Palaearctic L. vomerata .

Distribution (Map 9). Boreo-montane and arctic regions of the western Nearctic (Yukon Territory, Alaska, Wyoming to New Mexico).

Discussion. This species is very similar to the eastern Palaearctic L. vomerata , known only from the male holotype (not examined by us but illustrated in detail by Roháček & Papp, 1983). Both species differ from all other species in the L. fontinalis group by the notched ventral lobe of the anterior section of the surstylus. Leptocera neovomerata sp.n. differs from its Palaearctic sister species as follows: mid tibia with bristle above distal dorsal long, longer than bristle above distal anterodorsal and longer than anteroapical bristles (in L. vomerata shorter than former and probably shorter than latter as well); posteroapical bristles long, extending at least to socket of ventrobasal metatarsal bristle (stopping clearly short of it in L. vomerata ); anterior process of surstylus more slender (not always as pronounced as in the male from Wyoming, illustrated in Fig. 177); ventral lobe of anterior section of surstylus less prominent, rising gradually in front of notch (rising abruptly and vertically in L. vomerata ); inner ridge adjacent to notch with two distinct bristles, partly hidden behind larger outer lobe (in L. vomerata there appears to be only one bristle, the other one is shifted far posteriorly and inserted at the same level as the long posterior bristle of the anterior section of the surstylus). One character that has not previously been used in Leptocera taxonomy, the relative length of the bristle above the distal dorsal mid tibial bristle, has proven very reliable and useful in Nearctic material of the L. fontinalis group. In our opinion, this character in conjunction with genitalic characters convincingly establishes the distinctness of this taxon.

Figures

FIGURES 199–209. Postgonites and aedeagal complex of Leptocera fontinalis group (excluding L. cymatonota subgroup). Postgonites of (199) L. angulispina sp.n. (Canada), (200) L. finalis (Canada), (201) L. kanata sp.n. (Canada), (202) L. neofinalis sp.n. (Canada), (203) L. parafinalis (Canada), (204) L. neovomerata sp.n. (U.S.A.), (205) L. tenuispina sp.n. (Canada). Aedeagal complex of L. fontinalis (Spain): (206) posterior; (207) anterior; (208) lateral; (209) dorsal. bcp—basal connection between postgonites, bp—basiphallus, dp—distiphallus, ea—ejaculatory apodeme, pa—phallapodeme, pg—postgonites.