Leptocera angulispina Buck, 2009

Buck, Matthias & Marshall, Stephen A., 2009, Revision of New World Leptocera Olivier (Diptera, Sphaeroceridae), Zootaxa 2039 (1), pp. 1-139 : 75-77

Leptocera angulispina Buck , new species

( Figs. 148–154 , 199 )

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

Description. On average slightly darker and smaller than related species. Enlarged acrostichals short and not very conspicuous, only about half as long as lower orbital bristle; prescutellar acrostichals not enlarged. Mid tibia with bristles relatively short: bristle above distal dorsal shorter than anteroapical bristles; posteroapical bristles of same length, extending barely to socket of ventrobasal metatarsal bristle.

Male terminalia ( Figs. 148–151 ): Sternite 5 with posteromedial desclerotized area somewhat small. Anterior section of surstylus with anterior process in lateral view more or less rectangular and relatively short; bare lateral ridge at apex of anterior process prominent and darkened (best seen in ventral view); ventral lobe rounded, not very prominent, with short bristles that are separated by a noticeable gap from the long, basal, posterior bristle. Posterior section of surstylus with few bristles on dorsal (posterior) surface and unequal apical bristles. Postgonite as in Fig. 199 .

Female terminalia ( Figs. 152–154 ): Hind margin of sternite 7 produced medially. Sternite 8 with lateral margins slightly sinuate, posterolateral lobes relatively short, median process wide. Spermathecae subcylindrical, with scattered spicules, shallow apical invagination and similar basolateral depression (in paired spermathecae on side facing other spermatheca); surface weakly striate.

Type material. Holotype ♂ ( DEBU): U.S.A., Alaska, Richardson Hwy mi 206, 19.vi.1987, beaver pond, sweep, S.A. Marshall . Paratypes (all DEBU): 2 ♀♀, same data as holotype ; 1 ♂, same but from debris on beaver run, 1 ♂, 2 ♀♀, same but from beaver pond mammal runs; 2 ♀♀, same but from debris nr. beaver pond; 2 ♀♀, same but from beaver dam. U.S.A. Alaska : 3 ♂♂, 1 ♀, Glenn Hwy 25 mi N Gakona, 18.vi.1987, alder /wet moss, S.A. Marshall. CANADA. Yukon Territory : 2 ♂♂, 2 ♀♀, Dempster Hwy, Tombstone Mts , 3.vii.1985, river gravel, flood debris, S.A. Marshall; same as previous but 4.vii.1985, flood debris nr. ice ; 1 ♀, Dempster Hwy, Tombstone Mtn Camp , 6–12.vii.1985, mushroom trap in Sphagnum /lichen, S.A. Marshall ; 1 ♂, Dawson City, Klondike Hwy km 45, 9–12.vii.1985, hydro cut, FIT in willow / Equisetum, S.A. Marshall .

Other material examined. CANADA. Yukon Territory: 1 ♀, Klondike Hwy km 300, 23.vi–14.vii.1987, willow / spruce, carrion trap, S.A. Marshall ( DEBU) ; 1 ♀, Erebia Creek , base camp, 67°58’N 136°29’W, 10.vii.1987, carrion trap by creek, S.A. Marshall ( DEBU) .

Etymology. The species name is a noun in apposition and refers to the angulate anterior process of the anterior section of the surstylus and the similarity to the eastern Palaearctic L. equispina .

Distribution (Map 8). Restricted to the Yukon Territory ( Canada) and Alaska ( U.S.A.). One locality is located within a kilometre from the border with the Northwest Territories so the species should be expected there as well.

Discussion. Leptocera angulispina sp.n. is very similar to L. tenuispina sp.n. from British Columbia, L. equispina from the eastern Palaearctic, and to a lesser degree to the trans-Nearctic L. kanata sp.n. It differs from all these species by the less prominent ventral lobe of the anterior surstylar section, the more basally (dorsally) positioned long posterior bristle of the latter, and the shorter, angulate anterior process of the anterior surstylar section. Males of L. kanata sp.n. furthermore possess stronger bristles on the ventral lobe of the anterior surstylar section. Females of L. angulispina sp.n. differ from all mentioned species by the slightly sinuate (not angulate) lateral margins of sternite 8, and the shorter posterolateral lobes of the latter.

Figures

FIGURES 148–154. Leptocera angulispina sp.n. (U.S.A., except 153: Canada). Male terminalia (phallus and postgonites omitted): (148) lateral; (149) posterior; (150) ventral; (151) sternite 5. Female terminalia: (152) dorsal; (153) spermathecae; (154) ventral. aps—anterior process of anterior section of surstylus, ce—cercus, cp—ventral process of cercus, ep—epandrium, fm—field of dense microtrichia, ha—hypandrial apodeme, hy—hypandrium, pa—phallapodeme, pss—posterior section of surstylus, S—sternite, se—subepandrial sclerite, T—tergite (female tergite 8 divided into two halves), vls—ventral lobe of anterior section of surstylus.

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.