Crucisternum ouboteri, 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 : 118

Crucisternum ouboteri sp. n. Figs 2A-D ; 4 ; 5A, B ; 6A, B ; 7 ; 8A-C

Type material examined.

Holotype (male): " SURINAME: Sipaliwini district/ 04°56.871'N, 55°10.911'W, 462 m/ Brownsberg Nature Park, forested/ stream with lots of detritus; leg./ Short, Maier, McIntosh; 4.viii.2012/ SR12-0804-01A" // "Barcode/ SEMC1113824/ KUNHM-ENT" (NZCS). Paratypes (155): GUYANA: Region IX: " 2°06.492'N, 59°13.653'W, 274 m/ Parabara, N. side of river/ small flowing forested creek/ detritus margins & leaf packs/ leg. Short, Isaacs, Salisbury/ 3.xi.2013; GY13-1103-02A" (5, SEMC). FRENCH GUIANA: Roura: "[Patawa: crique/ Diamant]/ 16.xi.2007/ P. Queney réc.” (1, PQPC). SURINAME: Sipaliwini district: " 2°21.776'N, 56°41.861'W, 237 m/ Camp 3, Wehepai; leg. Short &/ Kadosoe; sandy forest creek/ 4-6.ix.2010; SR10-0904-01A/ 2010 CI-RAP Survey" (2, SEMC); " 2.97731°N, 55.38500°W, 200 m/ Camp 4 (low), Kasikasima; sandy stream on trail to METS camp/ 20.iii.2012; SR12-0320-02A/ leg. A. Short; 2012 CI-RAP Survey" (27, SEMC, including DNA voucher SLE 472); same, except "sandy creek, trail to Kasikasima/ 22.iii.2012; SR12-0322-02A" (12, SEMC); " 04°42.480'N, 56°13.159'W, 24 m/ Raleighfallen Nature Reserve, trail/ to Raleighfallen; creek margins/ leg. Short, McIntosh, & Kadosoe/ 27.vii.2012; SR012-0727-03A" (1, SEMC); same data as holotype (89, NZCS, SEMC, MALUZ). VENEZUELA: Amazonas: "Cerro de la Neblina, basecamp 140m./ 0°50'N, 66°10'W / 18 February 1985// Berlese of leaf packs/ among rocks in small/ stream in rainforest/ P.J. & P.M. Spangler, R. Faitoute, W. Steiner" (16, USNM, MIZA); same, except "rainforest at black light/ 21.ii.1985; leg. Spangler et al." (1, USNM).

Differential diagnosis.

Crucisternum ouboteri is very similar to C. vanessae and C. queneyi in the sharpness of the punctation (compare Fig. 2A-D to 2E-H and Fig. 1E-H ). It is nearly indistinguishable from C. toboganensis based on external characters beyond coloration (uniform along the body in C. toboganensis , paler pronotum in C. ouboteri ). Crucisternum ouboteri can be recognized by the fusiform aedeagus, with the apical third of the parameres parallel-sided with sinuate outer margins (Fig. 6A, B ).

Description.

Body length 2.0-2.4 mm, width 1.2-1.4 mm. General coloration dark brown on elytra, slightly paler on pronotum and head (Fig. 2A ). Elytra with punctures rather sharply marked. Aedeagus fusiform, widest near mid length; median lobe gradually narrowing from basal fifth towards apical region; gonopore usually presented longitudinally on apical region of median lobe; apical third of parameres parallel-sided, with sinuate outer margins (Fig. 6A, B ).

Etymology.

Named in honor of Dr. Paul Ouboter, director of the National Zoological Collection of Suriname and leading authority on the biodiversity of Suriname. Dr. Ouboter’s assistance has been invaluable in our efforts to document the water beetle fauna of the country.

Distribution.

French Guiana, Guyana, Suriname, and Venezuela (Amazonas). See Fig. 7 . Collected at 24 - 462 m elevation.

Biology.

This species is known from densely forested streams throughout much of the Guiana Shield region of South America (e.g., Fig. 8A-C ). One specimen was collected at a UV light in southern Venezuela.

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 2. Habitus of Crucisternum spp.: A-D Crucisternum ouboteri: A dorsal view, B lateral view C ventral view, D head E-H Crucisternum vanessae: E dorsal view F lateral view G ventral view H head. Scale bars: 1 mm.

Figure 4. Thorax and abdomen of Crucisternum ouboteri: A ventral view of mesoventrite (white arrow pointing longitudinal carina and transverse ridge); B posterior view of metafurca: (at) anterior tendon, (c) crux, (ds) dorsal sheath, (fa) furcal arm, (h) hemiductus, (ls) lateral sheath, (s) stalk; C fifth abdominal ventrite.

Figure 5. SEM images of thorax and abdomen: A-B Crucisternum ouboteri: A meso- and metaventrite B apex of fifth abdominal ventrite; C-D Nanosaphes tricolor C meso- and metaventrite D apex of fifth abdominal ventrite.

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.