Crucisternum escalera, 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 : 116-117

Crucisternum escalera sp. n. Figs 1A-D ; 6I ; 7 ; 8E, F

Type material examined.

Holotype (male): " VENEZUELA: Bolívar State/ 6°2'10.5"N, 61°23'57.8"W, 630 m/ Along La Escalera; 31.vii.2008/ leg. A. Short, M. García, L. Joly/ AS-08-058; rocky stream" // "Barcode/ SM00828756/ KUNHM-ENT" (MIZA). Paratypes (2): Same data as holotype (SEMC, 2).

Differential diagnosis.

Crucisternum escalera is very similar to C. sinuatus and C. xingu in the shallowness of the punctation and the uniform coloration along the body. It shares with C. sinuatus the shape of the median lobe (constricted at midlength, continuing as a narrow and roundly pointed bar, see Fig. 6 G-I ), but can be distinguished from it by the outer margins of the parameres, which are widely curved, to at most slightly sinuate (see Fig. 6I ; as opposed to strongly constricted near midlength, Fig. 6G, H ).

Description.

Body length 2.1-2.2 mm, width 1.1-1.2 mm. General coloration uniformly orange brown (Fig. 1 A-D ). Elytra with punctures shallowly marked. Aedeagus (Fig. 6I ) with outer margins of parameres widely curved, at most slightly sinuated; median lobe strongly constricted near midlength, continuing as a narrow and roundly pointed bar; gonopore located at midlength of narrow apical half of median lobe.

Etymology.

Noun in apposition. Named after the type locality of "La Escalera", which is the road that ascends from lowlands to the high-elevation plateau known as the "Gran Sabana".

Distribution.

Venezuela ( Bolívar). Collected at 630 m in elevation. See Fig. 7 .

Biology.

The only known series of this species was collected along the margin of a densely forested rocky stream. See Fig. 8E, F .

Figures

Figure 1. Habitus of Crucisternum spp.: A-D Crucisternum escalera: A dorsal view B lateral view C ventral view D head E-H Crucisternum queneyi: E dorsal view F lateral view G ventral view H head. Scale bars: 1 mm.

Figure 6. Aedeagus of Crucisternum spp.: A-B Crucisternum ouboteri: A Guyana B Brownsberg C Crucisternum toboganensis D Crucisternum vanessae E-F Crucisternum xingu: E colln 6 F colln 23 G-H Cuscisternum sinuatus: G colln 23 H BR 18 - 0302 - 04 A I Crucisternum escalera J Crucisternum queneyi. Scale bars: 0.25 mm.

Figure 7. Distribution of Crucisternum species.

Figure 8. Habitat of Crucisternum spp. A-B Habitat for C. ouboteri Suriname, Raleighvallen, collecting event SR 12 - 0727 - 03 A C Type locality and habitat for C. ouboteri, Suriname, Brownsberg Nature Park, collecting event SR 12 - 0804 - 01 A D Type locality and habitat for C. vanessae, Suriname, Tafelberg Summit, Caiman Creek, collecting event SR 13 - 0819 - 05 D E-F Type locality and habitat for C. escalera, Venezuela, Bolivar State, along La Escalera, collecting event AS- 08 - 058.