Xystosomus negrei, 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 : 12

7. Xystosomus negrei , new species

FIGURES 12 , 29 , 69

TYPE-LOCALITY.— Rancho Grande, Maracay , Venezuela.

TYPE-SPECIMENS.—The holotype male is in

MHNP. Two male paratypes: JNeg, 1; USNM, 1.

DESCRIPTION.—Form: As in X. strigosus, but easily distinguished from that species and all others in the group by the long carinae of the pronotum.

Color: Head and body dark piceous, almost black; pronotum and elytra shiny and slightly iridescent; appendages testaceous or slightly infuscated.

Head: Broad between eyes; frontal furrows short and deeply impressed; eyes medium-sized and slightly prominent.

Pronotum ( Figure 12 ): Transverse (W/L, x 1.56; range, 1.45-1.58; 3 specimens); lateral setigerous pores at hind angles only (see Remarks); laterobasal carina well developed, extended to apical half of pronotum; hind angles about 90°; side margins explanate throughout, more so in basal half, and straight or slightly incurved at basal third.

Elytra: Striae 1-4 slightly impressed, at least in basal half, 5-8 effaced, those present unevenly punctulate; side margins explanate; humeral projection well developed, obtuse; chaetotaxy as in X. gruti ; plica small, evident externally.

Microsculpture: As in X. gruti .

Secondary sexual characters: Male genitalia (Figure 29) characteristic of the species group. Female unknown.

Size: Three specimens: length, 3.4—3.7 mm; width, 1.6-1.7 mm.

NATURAL HISTORY.— Unknown.

LOCALITY RECORDS ( Figure 69 ).—I have seen three specimens from the following locality:

SOUTH AMERICA: VENEZUELA: Rancho Grande, Maracay (MHNP, JNeg, USNM).

REMARKS.—Although the three known specimens do not possess the anterior pair of lateral setigerous pores, it is possible that this condition is variable. It is also possible that the longer carina of the pronotum effects the absence of a setigerous pore, making this the only species of the group without pores but with a longer carina.

Figures

FIGURE 69.—Approximate range of the gruti group.

FIGURES 7-21.—Pronotum, dorsal aspect: 7, Xystosomus ampliatus, female, Hamburg Farm, Costa Rica; 8, X. nigripalpis, female, Barro Colorado Island, Panama; 9, X. strigosus, female, Rio Parahyba, Brazil; 10, X. iris, female, Cochabamba, Bolivia; 11, X. sculpticollis, female, Teffe, Brazil; 12, X. negrei, male, Rancho Grande, Venezuela; 13, X. aetholius, female, Cochabamba, Bolivia; 14, X. anterocostis, Hamburg Farm, Costa Rica; 15, X. sublaevis, male, Rio Banano, Costa Rica; 16, X. sulcicostis, female, Volcan de Chiriqu!, Panama; 17, X. apicisulcatus, female, Minas, Brazil; 18, X. batesi, female, Petr6polis, Brazil; 19, X. seriatus, female, Nova Teutonia, Brazil; 20, X. ovatulus, female, Caraca, Brazil; 21, X. grossipunctatus, female, Caraca, Brazil.

FICURES 23-30.—Male genitalia, left lateral aspect of seven species of the gruti group: 23, Xysto- somus gruti, Volcan de Chiriqui, Panama; 24, X. gruti, apex of median lobe, Hamburg Farm, Costa Rica; 25, X. nigripalpis, Barro Colorado Island, Panama; 26, X. strigosus, Rio Parahyba, Brazil; 27, X. iris, Cochabamba, Bolivia; 28, X. sculpticollis, Sao Paulo d'Olivenc,a, Brazil; 29, X. negrei, Rancho Grande, Venezuela; 30, X. aetholius, Cochabamba, Bolivia.