Tropisternus (Pristoternus) surinamensis Spangler & Short

Spangler, Paul J. & Short, Andrew Edward Z., 2008, Three new species of Neotropical Tropisternus Solier (Coleoptera: Hydrophilidae), Zootaxa 1917, pp. 65-68 : 67-68

Tropisternus (Pristoternus) surinamensis Spangler & Short , sp. n.

Type material: Holotype (female): “ SURINAM; Krakka/ Phedra road, x-25-62 / tiny forest pool/ Borys Malkin” ( NMNH).

Diagnosis: This species is similar to T. robustus Sharp, 1883 , but T. surinamensis may be distinguished from T. robustus and other closely related species by the large trapezoidal basal pubescent area of the hind femur rather than the triangular basal pubescent area of the hind femur of the other species of the group. In addition, T. surinamensis is the only known species in the genus with microreticulate sculpture between the punctures on the mentum.

Description: Body length 12.7 mm; greatest body width 6.4 mm. Color: Dorsal surface of head, pronotum, and elytra black with greenish tinge. Labrum reddish brown. Basal 6 antennal segments testaceous, remainder dark reddish brown. Labial and maxillary palpus testaceous but apices slightly darker. Ventral surface black except inflexed portion of pronotum, epipleura, trochanter, sternal keel between forecoxae, femoral apices, and outer margins of tibiae and tarsi reddish brown. Head: Finely, densely punctate except an interocular series of 24 to 28 coarse, setigerous punctures and an anterolateral series of 12 to 15 coarse, setigerous punctures. Labrum finely, moderately densely punctate basally; more densely punctate apically. Mentum alutaceous and coarsely, moderately densely punctate; punctures separated by a distance about equal to their width. Submentum more finely alutaceous; punctures slightly smaller than those on mentum and sparse laterally. Thorax: Pronotum feebly sinuate laterally, bisinuate basally; slightly narrower at base than base of elytra; posterolateral angles obtuse, rounded; finely densely punctate similarly to head; finer punctures separated by a distance twice their width; mediolateral series of 13 to 16 coarse, setigerous punctures; anterolateral series of 12 to 15 coarse, setigerous coalesced punctures forming a single setigerous pit. Elytron very fine, moderately densely punctate; with 9 series of very fine punctures, 3 series of coarse, setigerous punctures and, adjacent to epipleuron, a row of dense, moderately coarse punctures; epipleuron with moderately coarse punctures from base to apex; apex acute. Sternal keel attaining middle of second abdominal ventrite. Mesoventral portion of keel moderately wide, widest in basal threefourths; feebly convex; with few coarse, setigerous punctures laterally and medially; punctures denser apically. Metaventral portion of keel densely, coarsely punctate; punctures aciculate and setigerous; canaliculate medially; tapering to a stout, acute spine. Metafemur broad, convex, arcuate; densely, coarsely punctate on apical half; pubescent area large, trapezoidal, extending a distance one-half length of trochanter. Metatibia almost parallel sided in apical half, subcylindrical, without fringed groove on upper surface. Inner mesotarsal and metatarsal claws robust, without teeth. Abdomen: Apical margin of fifth abdominal ventrite with long, slender spine with few golden hairs on apex.

Etymology: Named for the country from which the species was collected.

Bionomics: The single specimen of T. surinamensis was collected from a "tiny forest pool."

Distribution: Only the type specimen from Suriname is known.