Xystosomus impressifrons, 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

29. Xystosomus impressifrons , new species

FIGURES 56 , 65 , 68 , 72

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

TYPE-SPECIMENS.—The holotype male and allotype are in MHNP. Both were collected by P.

Germain in 1884. Thirty-one paratypes: MHNP, 18; JNeg, 3; USNM, 10.

DESCRIPTION.— Form ( Figure 56 ): Short and broad with highly convex elytra, moderately broad, short pronotum, and narrow head. Easily distinguished by the presence of two pairs of lateral setigerous pores on the pronotum.

Color: Head and forebody rufopiceous; elytra usually more rufous; pronotum and elytra slightly iridescent; appendages testaceous or slightly infuscated, especially femora and distal antennal articles.

Head: Broad between eyes; frontal furrows moderately impressed, frons between furrows either slightly convex or depressed transversely; eyes medium-sized, moderately prominent.

Pronotum ( Figure 56 ): Transverse (W/L, x 1.65; range, 1.47-1.77; 33 specimens); lateral setigerous pores present at apical third and at hind angles; laterobasal carinae absent; 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 , except head with more evenly isodiametric meshes.

Secondary sexual characters: Male genitalia (Figure 65) and female genitalia (Figure 68) characteristic of the species group.

Size: Thirty-three specimens: length, 2.1-2.9 mm; width, 1.2-1.5 mm.

NATURAL HISTORY.— Unknown, except adults collected in February, April, May, August, and September. I have seen teneral specimens collected in all these months.

VARIATION.—Brazilian specimens from Rio Parahyba and Lagoa de Saquarema , and some from

Haut Macahe, have the frons transversely depressed posterior to the frontoclypeal line. Specimens from Nova Friburgo, Brazil, and others from Haut Macahe have the frons convex (i. e., normal for the

species group).

LOCALITY RECORDS ( Figure 72 ).—I have seen 33 specimens from the following localities:

SOUTH AMERICA: BRAZIL: Rio de Janeiro Province: Haut Macahe; Lagoa de Saquarema ; Nova Friburgo. Rio de Janeiro (Province?): "Rive gauche du Parahyba."

Figures

FIGURE 56.—Habitus of Xystosomus impressifrons, male, Lagoa de Saquarema, Brazil.

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

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.