Xystosomus niger, 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 : 32-34

30. Xystosomus niger , new species

FIGURES 60 , 67 , 72

TYPE-LOCALITY.— Serra da Bocaina , at 1,650 meters, Sao Jose Barreiro , Brazil.

TYPE-SPECIMENS.—The holotype male and allotype are in MHNP. Both were collected by M. Arvarenga in 1969. Three paratypes, from the typelocality: JNeg, 2; USNM, 1.

DESCRIPTION.— Form: Very broad and convex with small head and very broad pronotum. Easily distinguished from all other species of the group by the black integument or the swollen areas of the frons anterior to eyes and laterad of the frontal furrows.

Color: Head and body black; pronotum and elytra moderately iridescent; appendages testaceous or infuscated in part.

Head: Broad between eyes; frontal furrows shallow, laterally deflected almost at right angle to edge of eye; frons anterior to eye swollen; eyes medium-sized, large-faceted, slightly prominent.

Pronotum ( Figure 60 ): Very broadly transverse (W/L, x 1.81; range 1.79-1.88; 5 specimens); lateral setigerous pores absent; laterobasal carinae short, thick, low, and interrupting basal groove; hind angles obtuse, sides anterior to angles evenly arcuate; side margins beaded, not reflexed.

Elytra: Smooth; as in X. laevis .

Microsculpture: As in X. laevimicans .

Secondary sexual characters: Male genitalia (Figure 67) and female genitalia characteristic of the species group.

Size: Five specimens: length, 2.5-2.7 mm; width, 1.36-1.44 mm.

NATURAL HISTORY.— Unknown, except all specimens collected in January. No teneral specimens seen.

LOCALITY RECORDS ( Figure 72 ).—I have seen five specimens from the following locality:

SOUTH AMERICA: BRAZIL; Sao Jose Barreiro, Serra da Bocaina (JNeg, USNM).

Figures

FIGURE 72.—Approximate range of the inflatus and laevis groups.

FIGURES 57-62.—Pronotum, dorsal aspect: 57, Xystosomus laevis, female, Nova Teutonia, Brazil; 58, X.paralaevis, female, Sao Paulo, Brazil; 59, X. laevimicans, female, Santos, Brazil; 60, X. niger, female, Serra Bocaina, Brazil; 61, X. tholus, male, Alto da Serra, Brazil; 62, X. turgidus, female, Rio Caraguata, Brazil.

FIGURES 63-68 Genitalia. 63-67, Male, left lateral aspect: 63, Xystosomus laevis, Nova Teutonia, Brazil; 64, X. laevimicans, Alto da Serra, Brazil; 65, X. impressifrons, Brazil; 66, X. tholns, Alto da Serra, Brazil; 67, X. niger, Serra Bocaina, Brazil. 68, Female, X. impressifrons, "Lagune de Sacuaresma," Brazil: a, bursa copulatrix; b, spermathecal reservoir.