Elachistelmis sipaliwiniensis, Maier, Crystal A., 2012

Maier, Crystal A., 2012, Elachistelmis gen. n. (Coleoptera: Elmidae: Elminae) from Suriname, with description of two new species, Zootaxa 3500, pp. 61-69 : 66-69

Elachistelmis sipaliwiniensis sp. n.

( Figs. 7–8 , 12–14 , 22–25)

Type material. Holotype male: “ SURINAME: Sipaliwini District/ 2°10.973’N, 56°47.235’W, 210m / Camp 2, on Sipaliwini River/ leg. A.E.Z. Short; UV-light/ 27.viii–1.ix.2010; SR10–0827–LT2” Holotype deposited in the NZCS.

Paratypes: 10 specimens, same data as holotype. Paratypes will be deposited in: 1 in NZCS, 1 in NMW, 1 in BMNH, 6 in SEMC (three mounted on SEM stub and gold-coated), and 1 in USNM.

Diagnosis. This species can be distinguished from all other described species of Elmidae by the small size (ca. 1.0 mm) pronotum with sublateral carinae and lacking depressions ( Fig. 13 ), and the presence of a narrow band of plastron setae on the lateral edge of each elytron. This species can be separated from its congener by the pentamerous tarsi (Fig. 23), hind wings without setal fringe, the rounded apex of the prosternal process (Fig. 23), and the uniformly testaceous coloration, with slightly lighter elytral humeri.

Description. Holotype Male. Body elongate, subparallel, dorsum moderately convex ( Fig. 13 ). Length, 1.0 mm; greatest width 0.5 mm. Dorsal surface sparsely setose. All appendages testaceous. Body entirely testaceous, elytra becoming slightly lighter near humeri ( Fig. 12 ).

Head microreticulate. Eye hemispherical, separated by a distance 2.5 times the radius of eye. Antenna with sparse, short setae, apical antennomere spindle-shaped (Fig. 24). Clypeus explanate laterally. Labrum rounded apically; surface with fine punctation and covered with sparse, golden setae. Lacinia and galea long; apical palpomere of maxillary palpus spindle-shaped. Labium apically with a brush short hair-like setae. Labial palpus set into a furrow at base of labium. Apical palpomere of labial palpus cylindrical, bearing a patch of sensilla at apex (Fig. 24).

FIGURES. 22–25. Elachistelmis sipaliwiniensis , n. sp.: 22. Abdominal ventrites; 23. Prosternum; 24. Head, ventral view 25. Metatarsus.

Pronotum 0.3 mm long, 0.3 mm wide, apex wider than base, widest point at apex, sides parallel in apical 2/3, narrowed in basal 1/3, with two complete, sublateral carinae; anterolateral angles acute, slightly explanate and slightly depressed behind each angle; posterolateral angles acute, slightly explanate;, surface covered with very sparse setae and fine, dense, shallow punctures, punctures more dense anteriorly, discal area free from impressions ( Fig. 13 ).

Prosternum very long in front of procoxae approximately two times as long as prosternal process; with sparse setae, coarsely microreticulate without sculpturing medially, with strong sinuate longitudinal carinae extending anterior of procoxae. Prosternal process expanded posterior to procoxae, forming a rounded diamond-shaped projection; lateral margins concave, with curve for reception of procoxae; apex rounded (Fig. 24). Mesoventrite with with sparse setae, coarsely microreticulate. Metaventrite coarsely microreticulate posterior to mesocoxae, densely setose laterally, with long flattened setae, glabrous at center line; disc with distinct, deep, longitudinal groove medially ( Fig. 14 ). Procoxae and metacoxae moderately widely separated; mesocoxae slightly more widely separated. Legs long and slender. Femora glabrous. Protibiae, mesotibiae, and metatibiae with apical cleaning fringe ( Fig. 14 ). Tarsi pentamerous on all legs, claws long and stout (Fig. 25).

Elytron with seven rows of weak, shallow punctures; punctures separated by a distance roughly six times the diameter of the puncture; intervals with fine, very sparse setae, smooth and without sculpturing ( Fig. 13 ); elytron with two weak carinae, lateral carina reaching elytral apex, sublateral carina in apical 0.65, with dense setae of plastron lateral of lateral carina; elytral plastron setae long (ca. 0.2 mm), with short lateral projections on the entire length of the seta. Hind wing lacking long setal fringe.

Abdomen with five ventrites; cuticle densely covered with setae, with glabrous patch medially ( Fig. 14 ). First ventrite with intercoxal process broadly, shallowly depressed and distinctly carinate adjacent to metacoxae; carinae extending longitudinally behind metacoxae for half the length of ventrite; area posterior to metacoxae coarsely microreticulate. Second ventrite of males with two ventrally produced sensilla medially (Fig. 22). Last visible ventrite broadly rounded, with lateral hook-like projections.

Aedeagus as illustrated, elateriform, median lobe of aedeagus pointed apically, 1.2 times as long as wide ( Fig. 7 ).

Female. Externally identical to male (tend to be larger in size), lacking two ventrally produced tubercles medially on second abdominal ventrite. Gonostylus with row of stout teeth laterally ( Fig. 8 ).

Intraspecific Variation. All specimens from this locality were testaceous in color, though this may be a result of them being teneral adults, in which case the true color of adults of this species is not known. The species also varies in size, from 1.0– 1.2 mm long.

Etymology. The specific epithet, “ sipaliwiniensis ” is a reference to the type locality of the Sipaliwini District and River in the South American country of Suriname.

Habitat. The habitat for this species is unknown, as they were collected at a UV light approximately 30 m from the Sipaliwini River ( Short and Kadosoe 2011). The specimens were collected in a blacklight trap along with several hundred other elmids comprising seven different genera, as well as specimens of the type species, E. tetramera . This species, though, is far more rare than the type species in the sample, with only ten individuals collected.

Figures

FIGURES 5 – 8. Elachistelmis tetramera, n. sp.: 5. Male genitalia, ventral view 6. Female genitalia, ventral view. Elachistelmis sipaliwiniensis, n. sp.: 7. Male genitalia, ventral view 8. Female genitalia, ventral view. Scale bar = 0.1 mm.

FIGURES 9 – 14. Elachistelmis tetramera, n. sp.: 9. Habitus, dorsal view, showing coloration; 10. Habitus, dorsal view, SEM; 11. Habitus, ventral view. Scale bar = 0.5 mm. Elachistelmis tetramera, n. sp.: 12. Habitus, dorsal view, showing coloration; 13. Habitus, dorsal view SEM; 14. Habitus, ventral view. Scale bar = 0.6 mm.