Bregmosina schizosterna, Marshall, Stephen A., 2013

Marshall, Stephen A., 2013, Bregmosina, a new Neotropical genus of Limosininae (Diptera: Sphaeroceridae), Zootaxa 3641 (3), pp. 260-270 : 268-269

Bregmosina schizosterna new species

Figs. 23–26

Description (male only): Length (antennal base to wing tip) 2.6 mm. Eye height 2.7X genal height. Tarsomeres 1– 5 of fore leg strikingly broad and flat, broader than fore tibia, broadest at middle with distal part of tarsomere 1 and all of tarsomeres 2 and 3 of equal width, each tarsomere progressively slightly shorter. Tarsomeres 1 and 2 of hind leg strongly swollen; second tarsomere as long as tarsomeres 3, 4, and 5 combined. Mid tibia with 4 distal dorsal bristles, including a long anterodorsal, a long dorsal and short (length equals tibial width), subequal dorsal and posterodorsal bristles. Mid tibia with two apical ventral bristles.

Male abdomen: All sternites strongly modified, sternites 2–5 completely divided medially. Sternites 3–5 with each half including a broad lateral plate and a narrow medial arm, sternite 5 further including a posterior lobe with a cluster of short, stout bristles on its medial surface followed by a pale, long-setose medial surface. Ventral part of sternite 6 narrow, with an anterior concavity facing genital pouch. Ring sclerite not seen. Cerci broad, separate, diverging distally and tapered to a nipple-like distal medial apex. Surstylus elongate-rectangular, apex symmetrically tapered to a narrow lobe. Postgonite with a broad base and a narrow, parallel sided distal portion. Basiphallus simple, without epiphallus. Distiphallus with a tubular base, a prominent flat posteromedial process, and broad, rounded distal arms.

Type material. Holotype male (QCAZ): ECUADOR. Maquipucuna Biological Reserve. 1200 m, treefall, yellow pans, 26–28.iv.2002, M. Buck and S.A. Marshall (debu00202723).

Comments. Bregmosina schizosterna is a remarkably distinctive species because of the conspicuously modified abdominal sternites and the broadly swollen first tarsus, but other aspects of the male terminalia are similar to B. ephydriformia and B. bucki .

Etymology. Bregmosina schizosterna is named for the unusual split male sternites.

Figures

FIGURES 23 – 26. Bregmosina schizosterna. 23, male terminalia posterior; 24, male terminalia ventral / lateroventral (detail given for only left side of sternite 5); 25, epandrium and associated structures left lateral; 26, aedeagus and associated structures left lateral. Abbreviations: D, distiphallus; PG, postgonite; SU, surstylus; S 4 – 7, sternites 4 – 7.