Albistyla fimbriata, Marshall, Stephen A., 2014

Marshall, Stephen A., 2014, Albistyla, a new genus of Neotropical Limosininae (Diptera: Sphaeroceridae), Zootaxa 3793 (2), pp. 257-264 : 259-261

Albistyla fimbriata n.sp.

Figs. 1–5

Description. Abdomen: Syntergite 1+2 pale anteromedially, twice as long as tergite 3.

Male abdomen: S4 simple, lightly sclerotized. S5 with anterior part broadly bilobed and projecting under (dorsal to) S4; middle part with a blade-like central piece connecting with a dark U-shaped band on each side, middle part of each band with a pale, deeply fimbriate lobe; posterior margin of sternite developed into two conspicuously prominent processes, each in turn divided into a prominent longitudinal lobe with a row of 4–5 stout bristles and a posterior horizontal lobe with a darkened blade-like process. Surstylus folded into inner and outer lobes; outer lobe rounded and setose, inner lobe flat with a few marginal setae and a large, transparent, posteroventral scale. Cerci broad, lobate, narrowly fused dorsally. Distiphallus short-cylindrical with a very broad bilobed opening subtended by broad, flap-like distal lobes.

Female unknown.

Type material. Holotype (♂, MIZA): VENEZUELA. Maracay. Rancho Grande Biological Station, 1200m, pan traps in wet area, 25–28.ii.1995, S.A. Marshall.

Other material examined. COSTA RICA. Volcán Tenorio, N slope nr. Bijagua Biological Station, 700 m, pans in tree fall, 19.vi.2000, Buck and Marshall (♂, INBC). ECUADOR. Pichincha, Maquipucuna Biological Reserve, 1200m, compost pan traps, 27–29.Oct.1999, S.A. Marshall debu00111720 (♂, QCAZ).

Etymology. The specific name refers to the posterior fimbriate processes of male sternite 5.

Comments. The holotype is an excellent critical point dried male with all external genitalic structures, including the fimbriae referred to in the specific name, clearly visible. The fimbriae are not shown in Fig. 2 as they were not visible in ventral view on that dissection; they are visible on dissected material in posteroventral view (as in Fig. 1 ) although they are very pale and easily overlooked on cleared specimens.

There are slight differences between the Costa Rican, Venezuelan and Ecuadorian specimens treated as this species and it is possible that they represent a species complex with separate Central and South American species. The discal cell of the Costa Rican specimen lacks a stump vein and the second costal sector is slightly shorter than the third, while the South American specimens have a stump vein on the discal cell and have the second costal sector slightly longer than the third. Furthermore, the bristles on the posterior lobes on sternite 5 of the South American specimens are shorter and stouter. With only three specimens to work from, however, it is difficult to tell if these slight differences are intraspecific or interspecific.

Figures

FIGURES 1 – 5. Albistyla fimbriata male abdomen. 1, S 5 posteroventral, showing fimbriae (Costa Rican specimen); 2, segments 4 – 8 ventral; 3, terminalia left lateral (S 5 lateroventral); 4, phallus and associated structures left lateral; 5, epandrium and surstyli posterior. Figures 2 – 5 are from the Ecuadorian specimen. Abbreviations: S 5 – 8, sternites 5 – 8. T 5, tergite 5.