Oosternum luciae, Deler-Hernández & Cala-Riquelme & Fikáček, 2014

Deler-Hernandez, Albert, Cala-Riquelme, Franklyn & Fikacek, Martin, 2014, A review of the genus Oosternum Sharp of the West Indies (Coleoptera: Hydrophilidae: Sphaeridiinae), Deutsche Entomologische Zeitschrift 61 (1), pp. 43-63 : 43

Oosternum luciae sp. n. Figs 11-12 24 37 44 57 61

Type-locality.

Saint Lucia, Barre de L´Isle: 13.9368°N, 60.9593°W, 340 m.

Type-specimens

(1 spec.). Holotype male, dry mounted, with genitalia mounted in Euparal on a microslide pinned below the specimen. Original label: "ST LUCIA: Barre de L´Isle, 25/28.v.2009, E. A. Ivie, 13.9368°N, 60.9593°W, elevation 340 m, [printed] / Holotype, Oosternum luciae sp. n., Deler-Hernández & Fikáček det. 2013 [red, printed]" (WIFP).

Diagnosis.

Body widest ca at midlength. Lateral margin of pronotum weakly sinuate. Pronotal punctation uniform in size, moderately dense consisting of small, transverse punctures. Pronotal interstices with microsculpture. Mesal part of prosternum divided from lateral portions by oblique sharp ridges. Lateral margin of antennal grooves with acute projection. Elytral interval 2 narrower than interval 3, lower than intervals 1 and 3, reaching elytral apex. Elytral intervals 5, 7 and 9 distinctly higher than adjacent intervals. Elytral interstices shiny, without microsculpture. Preepisternal plate narrow, drop-like, 2.6 × longer than wide. Interstices of median portion of metaventrite with strong mesh-like microsculpture on the whole surface. Anterolateral ridges of metaventrite not meeting together mesally. Parameres 1.2 × longer than phallobase, bearing two short setae apically. Median lobe slightly longer than parameres, nearly parallel-sided basally, narrowing apicad in apical 0.4. Membranous lateral projections of median lobe present, with series of long setae on each side.

Description.

Habitus. Body widely oval, strongly narrowing posteriad; total leght /total width ratio = 1.3. Length: 1.41 mm; width: 0.87 mm.

Coloration. Coloration of dorsal side of head, pronotum and elytra dark brown. Ventral side brown.

Head. Clypeus with sparse punctation consisting of fine, each puncture bearing fine decumbent seta; setae pale; interstices with fine microsculpture; anterior margin of clypeus slightly concave. Frons with moderately dense punctation consisting of small, shallowly impressed rounded to slightly transverse punctures, punctures of same shape medially and laterally; interstices with fine mesh-like microsculpture. Eyes moderately large. Mentum 1.9 × wider than long, anterior margin slightly emarginate; anteromedian part deeply impressed in contrast to lateral portions; with sparse punctation, punctation consisting of small, nearly indistinct punctures bearing minute setae; interstices with fine microsculpture consisting of transverse ridges. Submentum without poriferous disc-like fields. Maxillary palpus with palpomeres 2 and 4 ca. 1.2 × longer than palpomere 3. Antenna with 9 antennomeres; scapus shorter than antennomeres 2-6 combined. Evenly convex.

Prothorax. Pronotum forming continuous curve with elytra in lateral view; lateral margin weakly sinuate, with narrow marginal bead. Pronotal punctation uniform in size, moderately dense, as dense as that on frons consisting of small, transverse punctures similar on whole surface of pronotum; punctures with minute setae intermixed among those bearing long setae; interstices with microsculpture. Transverse row of punctures on posterior margin of pronotum absent. Median portion of prosterum elevated and demarcated from lateral portins; median carina of prosternum narrow, projecting more anteriad mesally than anterior margin of median portion, with anterior portion elevated into small tooth in lateral view. Median portion of prosternum 1.8 × wider than long, postero-mesal projection with shallow notch. Pair of deep pits next to ridge delimiting median portion of prosternum present. Antennal grooves moderately large. Lateral margin of antennal grooves with acute projection.

Mesothorax. Scutellar shield bearing few minute rounded punctures; interstices without microsculpture. Elytral punctures coarse, shallowly impressed rounded to slightly transverse. Serial punctures small; transverse; sparsely arranged, with minute setae (indistinct under binocular microscope). Elytral interval 2 narrower than interval 3, lower than intervals 1 and 3, reaching elytral apex. Elytral intervals 5, 7 and 9 distinctly higher than adjacent intervals. Elytral interstices shiny, without microsculpture. Preepisternal plate narrow, drop-like, 2.6 × longer than wide, widely attached to metaventrite; posterior part of preepisternal elevation slightly overlapping over anterior margin of metaventrite, median part flat, bearing densely arranged, large, shallow setiferous punctures; interstices with very fine microsculpture, opaque.

Metathorax. Metaventrite ca. as long as preepisternal elevation of mesothorax, median portion markedly differing from lateral portion in punctation and microsculpture; punctation of median portion moderately dense, consisting of large, sharply impressed round setiferous punctures, interstices with strong mesh-like microsculpture on the whole surface. Anterolateral ridges bent posteriad along lateral margin of metaventrite, concave, laterally not meeting together mesally. Anterior margin of metaventrite not crenulate.

Abdomen. Ventrite 1 with additional longitudinal ridges laterally. Ventrites 2-5 without longitudinal ridges; posterior margin of all ventrites lacking denticles.

Male genitalia. Aedeagus 0.44 mm long, parameres 1.2 × longer than phallobase. Parameres continuously narrowing apicad, bearing two short setae apically. Phallobase narrow, 1.9 × longer than wide. Median lobe slightly longer than parameres, nearly parallel-sided basally, narrowing apicad in apical 0.4. Membranous lateral projections of median lobe present. Gonopore present.

Etymology.

The species name is derived from the woman’s name Lucia, referring to the presence of this species in the Saint Lucia island.

Distribution.

Oosternum luciae sp. n. is an endemic of Saint Lucia island and currently known only from the type locality ( Fig. 61 ).

Habitat.

Based on the label data, the type specimen was collected using an UV light trap.

Figures

Figure 61. Distribution of the representatives of the Oosternum from West Indies. Shape of the symbols indicate the species group which the respective species belongs to (see the Discussion for details).

Figures 1 - 12. Habitus of Oosternum from West Indies. 1 - 2. Oosternum andersoni sp. n., lenght = 1.25 mm (1. dorsal view, 2. lateral view). 3 - 4. Oosternum bacharenge sp. n., lenght = 1.40 mm (3. dorsal view, 4. lateral view). 5 - 6. Oosternum cercyonoides sp. n., lenght = 1.95 mm (5. dorsal view, 6. lateral view). 7 - 8. Oosternum insulare sp. n., lenght = 1.40 mm (7. dorsal view, 8. lateral view). 9 - 10. Oosternum latum Fikacek, Hebauer & Hansen, 2009, lenght = 1.50 mm (9. dorsal view, 10. lateral view). 11 - 12. Oosternum luciae sp. n., lenght = 1.41 mm (11. dorsal view, 22. lateral view).

Figures 19 - 28. Pronotal punctation and microsculpture. 19. Oosternum andersoni 20. Oosternum bacharenge 21. Oosternum cercyonoides 22. Oosternum insulare 23. Oosternum latum 24. Oosternum luciae 25. Oosternum megnai 26. Oosternum pecki 27. Oosternum sharpi 28. Oosternum sp. (Bahamas).

Figures 29 - 38. Median portion of prosternum. 29. Oosternum andersoni 30. Oosternum bacharenge 31. Oosternum cercyonoides 32. Oosternum megnai 33. Oosternum pecki 34. Oosternum sp. (Bahamas) 35. Oosternum insulare 36. Oosternum latum 37. Oosternum luciae 38. Oosternum sharpi.

Figures 39 - 44. Meso- and metaventrite plate. 39. Oosternum andersoni 40. Oosternum bacharenge 41. Oosternum cercyonoides 42. Oosternum insulare 43. Oosternum latum 44. Oosternum luciae.

Figures 53 - 60. Aedeagus. 53. Oosternum andersoni 54. Oosternum bacharenge 55. Oosternum insulare 56. Oosternum latum 57. Oosternum luciae 58. Oosternum megna i 59. Oosternum pecki 60. Oosternum sharpi.