Xystosomus polytretus, Erwin, 1973

Erwin, Terry L., 1973, Studies of the subtribe Tachyina (Coleoptera: Carabidae: Bembidiini), Part I: A revision of the Neotropical genus Xystosomus Schaum, Smithsonian Contributions to Zoology 140, pp. 1-39 : 25

21. Xystosomus polytretus , new species

FIGURES 44 , 70

TYPE-LOCALITY.— Nova Friburgo , Rio de Janeiro, Brazil.

TYPE-SPECIMEN.—The unique holotype female is in MHNP. It was collected by P. Germain in 1884.

DESCRIPTION.—Form: As in X. microtretus, but easily distinguished by the form of the pronotum, smaller eyes, and presence of eight rather than six rows of punctures on each elytron.

Color: Head and body rufous; pronotum and elytra moderately iridescent; appendages testaceous.

Head: Very broad between eyes; frontal furrows shallowly impressed and prolonged to posterior margin of eye; separated from supraorbital setigerous pores by narrow and sharp carinae; eyes small and nearly flat.

Pronotum ( Figure 44 ): Transverse-trapezoidal (W/L, 1.54); lateral setigerous pores present only at hind angles; laterobasal carinae rudimentary; hind angles about 90°, sides anterior to angles convergent to anterior angles; side margins narrowly explanate basally.

Elytra: Each elytron with eight rows of serial punctures, rows 2-7 effaced before apex; punctures large and coarse, separated by about their own diameter; side margins moderately explanate; humeral projection small, obtuse; chaetotaxy as in X. gruti ; plica long, evident externally.

Microsculpture: As in X. gruti .

Secondary sexual characters: Male genitalia unknown. Female genitalia characteristic of the species group.

Size: One specimen: length, 4.0 mm; width, 1.9 mm.

NATURAL HISTORY. Unknown, except the type was collected in "April-May." It is not teneral.

LOCALITY RECORDS ( Figure 70 ).—I have seen only the unique type from Nova Friburgo, Brazil.

Figures

FIGURE 44. -Pronotum, dorsal aspect, of Xystosomus polytretus, female, Nova Friburgo, Brazil.

FIGURE 70 Approximate ranges of the elaphrinus group (crosshatched area) and the micro- tretus group (solid areas).