Tropisternus richmondi

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

Tropisternus (s. str.) richmondi, Spangler & Short sp. n.

Type material: Holotype (male): “Exuma Cays/ Bells Island/ Jan. 14, 1953 ”, “Van Voast–A.M.N.H./ Bahamas Isls. Exped./ Coll. E. B. Hayden & L. Giovannoli” ( AMNH). Paratypes (9): BAHAMA ISLANDS: Same data as holotype, 2 males, 3 females ( AMNH, NMNH, KSEM); Simm's Long Island, vii.1963, 1 female ( MCZ). CUBA: Soledad, Cienfuegos, (22-24). xi.1926, grassy pond, P.J. Darlington, 3 females ( MCZ, KSEM).

Diagnosis: This species resembles T. setiger ( Germar, 1824) sensu d’Orchymont , but T. richmondi may be distinguished by the following characters: pronotal margin wider; posterolateral angles of pronotum acute and produced posteriorly; epipleura impunctate on basal portion; metafemur more robust and arcuate.

Description: Male body length 9.5 mm; greatest body width 5.0 mm. Female body length 8.8 mm; greatest body width 4.2 mm. Color: Dorsal surface of head, pronotum, and elytra black. Labrum dark reddish brown. Basal 6 antennal segments testaceous, remainder dark reddish brown. Labial and maxillary palpi testaceous but apices dark reddish brown. Ventral surface black except inflexed portion of pronotum, epipleura, legs distad of basal pubescent area, and sternal keel reddish brown. Male: Head: Finely, densely punctate except an interocular series of 7 or 8 coarse, setigerous punctures and an anterolateral series of 12 to 15 coarse, setigerous punctures. Labrum finely, sparsely punctate. Last segment of maxillary palpus with sensory region extending from apex a distance one-third as long as segment. Mentum moderately, coarsely punctate. Thorax: Pronotum sinuate laterally, feebly bisinuate basally; posterolateral angles acute, produced posteriorly; finely, sparsely punctate; punctures separated by about twice their width; mediolateral series of 7 or 8 coarse, setigerous punctures; and anterolateral series of 5 or 6 coarse, setigerous punctures coalesced into a single setigerous pit. Elytron finely, sparsely punctate similarly to pronotum but punctures less deeply impressed, larger punctures intermingled and uniformly distributed over elytron; with 4 series of coarse, setigerous punctures; epipleuron impunctate basally, distinctly punctate apically; apex obtuse. Sternal keel attaining middle of second abdominal ventrite. Mesoventral portion of keel moderately wide, widest in basal three-fourths, feebly convex; with coarse, irregularly placed, setigerous punctures. Metaventral portion of keel with very few, fine, aciculate, setigerous punctures; canaliculate medially; tapering to a needlelike spine. Metafemur broad, convex, arcuate; with 8 coarse, setigerous punctures apically; pubescent area triangular, extending from apex of trochanter anteriorly a distance twice as long as trochanter. Metatibia almost parallel sided in apical half, subcylindrical; with fringed groove on upper surface. Inner mesotarsal and metatarsal claws each with a moderate tooth arising submedially. Abdomen: Apical margin of fifth ventrite with feeble median carina with small tuft of golden hairs at apex. Aedeagus as illustrated ( Fig. 2 ). Female: Similar to male except mentum less coarsely and less densely punctate; mesotarsal and metatarsal claws without teeth; mesoventral portion of sternal keel with coarse punctures apically.

Variation: The specimens examined varied very little. However, a minor variation occurred in the length of the sternal keel. In several of the 10 specimens examined, the metaventral spine just attained the hind edge of the first abdominal ventrite; in other specimens, the spine extended to the middle of the second abdominal ventrite. The specimens vary in length and width from 9.0 mm x 5.0 mm to 10.75 x 6.0 mm.

Etymology: A patronym, named for the late E. A. Richmond, whose pioneer work on the hydrophilid larvae contributed extensively to our knowledge of the biology of theses insects.

Bionomics: No ecological information is available for this species.

Distribution: This species is known only from the Bahama Islands and Cuba. The locality data indicate that this species occurs in lowland coastal habitats. Only the specimens included in the type material have been examined.

Figures

FIGURES 1 – 2. Dorsal view of the aedeagus of Tropisternus. 1: T. phyllisae sp. n. (paratype), 2: T. richmondi sp. n. (paratype) Scale bar = 0.5 mm.