Crucisternum xingu, Girón & Short, 2018

Giron, Jennifer C. & Short, Andrew Edward Z., 2018, Three new genera of acidocerine water scavenger beetles from tropical South America (Coleoptera, Hydrophilidae, Acidocerinae), ZooKeys 768, pp. 113-158 : 124-126

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scientific name

Crucisternum xingu

sp. n.

Crucisternum xingu sp. n. Figs 3E-H View Figure 3 ; 6E, F View Figure 6 ; 7 View Figure 7

Type material examined.

Holotype (male): " BRAZIL: Pará / Rio Xingu Camp 52°22'W, 3°39'S / Altamira, ca 60km S.; 14.x.1986/ leg. P. Spangler & O. Flint// Colln. #23, stream on/ left branch of trail 1" (USNM). Paratype (1): BRAZIL: Pará: same, except "3.x.1986; Colln. #6;/ 1st jungle stream on trail 1" (1, USNM).

Differential diagnosis.

Crucisternum xingu is very similar to C. sinuatus and C. escalera in the shallowness of the punctation and the uniform coloration along the body. It can be readily recognized by its dark brown coloration (as opposed to orange brown; compare Fig. 3E-H View Figure 3 to Fig. 1 View Figure 1 ), which is shared with C. sinuatus , from which it can be distinguished by the median lobe gradually narrowing towards the apex (see Fig. 6E, F View Figure 6 ; as opposed to constricted at midlength, continuing as a narrow and roundly pointed bar, see Fig. 6G, H View Figure 6 ), and the nearly straight to sinuate outer margins of the parameres (as opposed to strongly constricted at apical third, continuing nearly parallel).


Body length 2.2-2.4 mm, width 1.3-1.4 mm. General coloration uniformly dark brown (Fig. 3E View Figure 3 ). Elytra with punctures shallowly marked. Aedeagus with outer margins of parameres sinuate to nearly straight; inner margins of parameres concave along apical third; median lobe gradually narrowing towards apex; apex of median lobe rounded (Fig. 6E-F View Figure 6 ).


Noun in apposition. Named after the Xingu River where the known specimens were collected.


Brazil ( Pará). See Fig. 7 View Figure 7 .


This species is known from forest streams.