Hydraena tobogan, Perkins, Philip D., 2011

Perkins, Philip D., 2011, New records and description of fifty-four new species of aquatic beetles in the genus Hydraena Kugelann from South America (Coleoptera: Hydraenidae), Zootaxa 3074, pp. 1-198 : 33-34

Hydraena tobogan , new species

Figs. 49 (habitus), 51 (aedeagus), 187 (spermatheca), 197 (map)

Type Material. Holotype (male): Venezuela : Amazonas, Puerto Ayacucho (40 km S.), at Tobogan , sandy margins, colln. #10, 23 ii 1986, P. J. Spangler. Deposited in the MIZA. Paratypes (105): Venezuela : Amazonas, Road between Puerto Ayacucho and Samariapo, small stream, gravel/rock substrate, elev. 60 m, 5° 16.639' N, 67° 48.044' W, 6 i 2006, Short (AS-06-012) (14 SEMC); S. Puerto Ayacucho, El Tobogan de la Selva, isolated rock pools in shaded floodplain, elev. 125 m, 5° 23.207' N, 67° 36.922' W, 5 i 2006, Short, Torres (AS-06-011c) (3 SEMC); As above (AS-06-011e) (3 SEMC); As above (AS-06-011f) (3 SEMC); S. Samariapo, on Rio Sipapo, Communidad Cano Gato, sandy forest stream, elev. 100 m, 4° 58.845' N, 67° 44.345' W, 7 i 2006, Short, Torres (AS-06-016) (1 SEMC); Territorio Federal Amazonas, Puerto Ayacucho (40 km S.), at Tobogan , 22 i 1985, P. J. & P. M. Spangler, R. A. Faitoute, W. E. Steiner (3 USNM); same locality, 23 ii 1986, P. J. Spangler (colln. #11) (1 USNM); Puerto Ayacucho (40 km S.), at Tobogan , collected by pouring water over streambank and washing riparian insects into seine, colln. #11, 17 xi 1987, P. J. Spangler & R. A. Faitoute (2 USNM); Puerto Ayacucho (40 km S.), at Tobogan , collected by pouring water over streambank & washing riparian insects into seine, 18 xi 1987, P. J. Spangler & R. A. Faitoute (colln. #13) (12 USNM); Puerto Ayacucho (40 km S.), at Tobogan , from mat of rootlets at shore edge, colln. #14, 25 ii 1986, P. J. Spangler (7 USNM); Puerto Ayacucho (40 km S.), at Tobogan , rootlets at shore edge, 26 ii 1986, P. J. Spangler (colln. #19) (1 USNM); Puerto Ayacucho (40 km S.), at Tobogan , sandy margins, colln. #10, 23 ii 1986, P. J. Spangler (33 USNM); Puerto Ayacucho (40 km S.), El Tobogan , Cano Coromoto, berlesed damp leaves, ditch edge, 24 i 1989, P. J. Spangler, R. Faitoute, C. B. Barr (4 USNM); Puerto Ayacucho (40 km S.), El Tobogan , Cano Coromoto, seep at upper shelter, 23 i 1989, P. J. Spangler, R. Faitoute, C. B. Barr (1 USNM); Puerto Ayacucho (40 km S.), El Tobogan , Cano Coromoto, stream edge at upper shelter, 26 i 1989, P. J. Spangler, R. Faitoute, C. B. Barr (16 USNM).

Differential Diagnosis. A very distinctive species, with rather coarse and dense dorsal punctation, relatively deep pronotal foveae, and a distinct scintilla. Pronotal fovea PF1 is T-shaped, with a median posterior extension that attains the space between foveae PF2. The elytral punctures are deep and closely spaced, interstices only about 0.5–1xpd. Similar in size and metaventral plaques, and somewhat similar in dorsal habitus to H. reverberata ( Figs. 49 , 52 ); differing therefrom by the more impressed pronotal foveae, the T-shaped PF1, and having fewer random punctures on the elytra. The aedeagi of the two species differ markedly ( Figs. 51, 54); the aedeagus of H. tobogan might be more favorably compared with that of H. scintillamima ( Fig. 37), but again the differences are great.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.24/0.54; head 0.22/0.31; pronotum 0.32/0.44, PA 0.34, PB 0.39; elytra 0.73/0.54. Dorsum of head dark brown to piceous; pronotum brown around subrectangular dark brown macula, ratios of color bands, as measured in midline, ca. 7/10/5; elytra dark brown; legs brown; maxillary palpi testaceous, tip not darker.

Frons punctures ca. 2xef, denser near eyes than medially; interstices laterally microreticulate, dull, ca. 0.5– 1xpd, medially weakly shining, ca. 1–2xpd. Clypeus microreticulate, dull, very finely sparsely punctulate medially. Mentum and postmentum microreticulate, finely punctulate, dull. Genae raised dull, with very low, narrow, illdefined posterior ridge.

Pronotum moderately arcuate laterally; anterior margin straight behind eyes, emarginate behind frons except slightly produced at distinct scintilla; punctures on disc much larger and deeper than those on frons, interstices weakly shining, 0.5–1xpd on disc, punctures larger and denser at anterior and posterior, often separated by narrow walls; PF1 moderately deep, T-shaped, with median posterior extension that attains space between PF2; PF2 deep; PF3 very deep; PF4 moderately deep; PF3 and PF4 shallowly confluent; low, indistinct ridge between PF3 and margin.

Elytra moderately arcuate laterally, broadly arcuate posteriorly; summit of posterior declivity at about midlength; lateral explanate margins wide; on basal 1/3 punctures slightly smaller than largest pronotal punctures, punctures becoming slightly smaller and more widely spaced toward posterior. Intervals not raised, effacedly microreticulate, very weakly shining, on basal 1/3 ca. 0.5–1xpd, as are interstices between punctures of a row, a few punctures subserial. Apices in dorsal aspect conjointly broadly rounded, in posterior aspect margins forming strong angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/0.5/3/4. P1 laminate; median carina sinuate in profile. P2 l/w ca. 2/1, sides slightly diverging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques very narrow, carinate lines, straight, slightly converging toward one another anteriorly, located at sides of median depression. Metaventrite with very small point on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at straight posterior margin ca. 2x P2. All legs rather short, robust. Protibia with prominent tooth on medial margin slightly past midlength, tooth bearing few short setae, medial margin excavate between tooth and apex of tibia. Meso- and metatibia straight. Male abdominal apex very slightly asymmetrical; last tergite with very small apicomedian notch. Female (microslide mount, n=1): last tergite broadly rounded, without apicomedian notch, ca. 14 sharply pointed, moderately closely spaced hooked setae; gonocoxite not midlongitudinally divided, setae rather long, apical margin sharply rounded, no transverse ridge evident at border of microreticulation; spermatheca type C1, very small.

Etymology. Named in reference to the now rather famous (in the water beetle world) type locality, and the Tshaped pronotal fovea PF1.

Distribution. Currently known from the type locality and a few nearby sites ( Fig. 197).

Figures

FIGURE 49. Hydraena tobogan, holotype, dorsal and lateral habitus, and venter.

FIGURE 52. Hydraena reverberata, holotype, dorsal and lateral habitus, and venter.