Xystosomus thoius, 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 : 34

31. Xystosomus thoius , new species

FIGURES 61 , 66 , 72

TYPE-LOCALITY.— Alto da Serra , Sao Paulo, Brazil.

TYPE-SPECIMENS.— The holotype male and allotype are in BMNH. Both were collected by G. E. Bryant in 1912.

DESCRIPTION.— Form: Very broad and convex, more so than any other species in group, similar in this respect to X. convexus of the inflatus group. Easily distinguished by the lack of lateral setigerous pores on the pronotum, obtuse hind angles of the pronotum, and straight frontal furrows.

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

Head: Broad between eyes; frontal furrows moderately impressed, straight, posteriorly divergent; eyes medium-sized, moderately prominent.

Pronotum ( Figure 61 ): Very broadly transverse (W/ L, x 1.87; range 1.85-1.89, 2 specimens); lateral setigerous pores absent; laterobasal carinae absent; hind angles obtuse, sides anterior to angles evenly

arcuate; side margins beaded, not reflexed except slightly near base.

Elytra: Smooth; as in X. laevis .

Microsculpture: As in X. laevimicans .

Secondary sexual characters: Male genitalia (Figure 66) and female genitalia characteristic of the species group.

Size: Two specimens: length, 2.48-2.54 mm; width, 1.26-1.34 mm.

NATURAL HISTORY.— Unknown, except adults collected in March. No teneral specimens seen.

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

SOUTH AMERICA: BRAZIL: Alto da Serra, Sao Paulo (BMNH).

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.