Derallus angustus Sharp, 1882

Short, Andrew Edward Z. & Torres, Phillip J., 2006, Review of the Hemiosus Sharp and Derallus Sharp of North America, Central America, and the Caribbean (Coleoptera: Hydrophilidae: Berosini), Zootaxa 1369, pp. 1-17 : 13

Derallus angustus Sharp, 1882

( Figs. 9 , 11 )

Derallus angustus Sharp, 1882: 78 ; Oliva, 1982: 158 (lectotype designation). Derallus Spegazzinii Bruch, 1915: 460 ; d’Orchymont, 1943: 79 (as synonym dubium); Syn: Oliva, 1981: 288.

Derallus angustatus [!]: d’Orchymont 1940: 196 (misspelling).

Type material examined. Lectotype (male): “ Derallus an/ gustus D.S./ Paso Antonio/ Guatemala 400 ft / Champion”, “Sharp Coll./ 1905.- 313 ”, “Paso Antonio,/ 400 ft./ Champion.”, “B.C.A. Col. I. 2. / Derallus / angustus ,/ Sharp.”, “ Derallus / angustus / J. Balfour-Browne det.”, “ LECTOTYPUS ”, “Oliva det.”, “Lecto-type [purple disc]” ( BMNH).

Additional material examined (117). BELIZE: Belize District: Western Highway near Zoo, light trap in pine grassland, 7.i. 2003, C.R. Bartlett leg. (1: AEZS). COSTA RICA: Guanacaste: laguna de crocodilo, near Carmona, 34 m, HG-vapor light, 16.i. 2003, A.E.Z. Short, R. Roughley, & W. Porras leg. (67: AEZS, INBio, NMW); 12 km S. of Cañas, UV light, 16.vi. 2003, A.E.Z. Short leg. (2: AEZS); Palo Verde National Park, shallow pool in gravel pit, 8.vi. 2000, R. Roughley leg., CR-00-08 (1: UMC); Puntarenas: Puntarenas, 2.vii. 1965, P.J. Spangler leg. (2: USNM). CUBA: Cayamas, E.A. Schwarz leg. (1: USNM). GUATEMALA: 15 mi. W Pijije, 5.viii. 1965, P.J. Spangler leg. (36: AE ZS, USNM). HONDURAS: La Lima, 3.xi. 1967, H.E. Ostmark leg. (1: USNM). MEXICO: Sinaloa: Elota, 1 mi. S, 1.viii. 1962, J.R. Zimmerman leg. (1: USNM); Veracruz: 25 mi. S Acayucan, 4.vii. 1965, P.J. Spangler leg. (2: USNM); Cotaxtla, Exp. Station, light trap, 24.vi. 1958 (1: USNM); Tabasco: Villahermosa, 6.viii. 1964, P.J. Spangler leg. (1: USNM); Campeche: 21 mi. E Campeche, 21.vii. 1964, P.J. Spangler leg. (1: USNM). Representative material deposited in MALUZ, MIZA, MFPC and NMW.

Diagnosis. Total length: 2.1 –3.0 mm. D. angustus is the most distinctive species of the genus in the region. It can be distinguished by the extremely fine pronotal punctation (which almost appears obsolete), the very weakly impressed elytral striae ( Fig. 9 ), the broad and strongly elevated mesosternal process, and the broadly elevated metasternum with a wide metasternal carina ( Fig. 11 ).

Distribution. Argentina, Belize (new record), Bolivia, Brazil, Cuba (new record), Costa Rica (new record), Guatemala, Honduras (new record), Mexico (new record), and Paraguay ( Oliva 1981, 1983).

Remarks. Described from Guatemala, Van Tassell (1966) also reports examining specimens from Brazil. There is one specimen identified by Van Tassell as D. angustus from Brazil in the CUIC collection, however this specimen represents a different species. Subsequently, Oliva (1981) recorded D. angustus from Argentina and Paraguay and then Amazonas State, Brazil ( Oliva 1983). In Costa Rica, this species has been taken in great numbers at lights in drying marshes of Guanacaste Province.

Figures

FIGURES 6 – 9. Lateral view of left elytron of Derallus. Arrows indicate the tenth elytral interstria. 6: D. altus (LeConte); 7: D. terraenovae Oliva; 8: D. rudis Sharp; 9: D. angustus Sharp. Scale bars 1.0 mm.

FIGURES 10 – 11. Ventral view of the metasternum of Derallus. 10: D. rudis Sharp; 11: D. angustus Sharp. Scale bar 0.2 mm.