Oosternum pecki, 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 pecki sp. n. Figs 15-16 26 33 46 49 52 59 61

Type-locality.

Dominican Republic, Barahona: 17°59 ’06.85” N, 71°12 ’57.29” W, 7 Km NW Paraiso, 200 m.

Type-specimens

(19 spec.). Holotype male, dry mounted, with genitalia mounted in Euparal on a microslide pinned below the specimen. Original label: "DOM REP: Barahona: 7 Km NW Paraiso, 27.xi/04.xii.1991, Masner & Peck, elevation 200 m, rainforest remnant, intercept tp. [printed] / Holotype, Oosternum pecki sp. n., Deler-Hernández & Fikáček det. 2013 [red, printed]" (CNC). Paratypes: DOMINICAN REPUBLIC: Barahona: same data as holotype (18 spec., CNC, NMPC, BSC-E, CMN, SEMC).

Diagnosis.

Body widest ca at midlength. Lateral margin of pronotum angulate. Pronotal punctation double-sized, dense consisting of moderately large round and rasp-like punctures. Pronotal interstices without microsculpture. Mesal part of prosternum not divided from lateral portions. Lateral margin of antennal grooves rounded. 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 wide, subrhomboid, 2.1 × longer than wide, largely overlapping over metaventrite. Interstices of median part of metaventrite without microsculpture. Anterolateral ridges of metaventrite not meeting together mesally. Parameres 1.1 × longer than phallobase, bearing two long setae apically. Median lobe ca. as long as parameres, nearly parallel-sided basally, narrowing apicad in apical 0.2, apex rounded. Membranous lateral projections of median lobe absent.

Description.

Habitus. Body elongate oval, gradually narrowing posteriad; total lenght/total width ratio = 1.6. Length: 1.45-1.5 mm, length of holotype: 1.41 mm; width: 0.89-0.97 mm, width of holotype: 0.89 mm.

Coloration. Coloration of dorsal side reddish brown. Ventral side brown to reddish brown. Femora, tibiae and antennal club pale reddish brown, tarsi and antennomeres 1-6 yellowish.

Head. Clypeus with sparse punctation consisting of fine punctures, each puncture bearing fine decumbent seta; setae pale; interstices without microsculpture; anterior margin of clypeus truncate. Frons with dense punctation consisting of small punctures of same shape medially and laterally; interstices without microsculpture. Eyes moderately large. Mentum 1.9 × wider than long, anterior margin slightly emarginate; anteromedian part not distinctly impressed; with sparse punctation, punctation consisting of minute, 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.

Prothorax. Pronotum evenly convex, forming continuous curve with elytra in lateral view. Lateral margin of pronotum angulate, with narrow marginal bead. Pronotal punctation double-sized, dense, slightly denser than on frons, consisting of transverse punctures anteriorly and large round punctures posteriorly; all punctures bearing long setae; interstices without microsculpture. Median portion of prosternum not elevated and demarcated from lateral portions, 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. Postero-mesal projection with deep notch. Antenal grooves moderately large. Lateral margin of antennal grooves rounded.

Mesothorax. Scutellar shield bearing a few small rasp-like punctures; interstices without microsculpture. Elytral series 1-5 and 8 arising basally, series 6-7 and 9 joint subbasally. 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, intervals 5, 7 and 9 distinctly higher than adjacent intervals. Elytral interstices shiny, without microsculpture. Preepisternal plate wide, subrhomboid, 2.1 × longer than wide, widely attached to metaventrite; posterior part of preepisternal elevation much overlapping over anterior margin of metaventrite; median part flat; bearing densely arranged, large, shallow setiferous punctures; interstices without microsculpture.

Metathorax. Metaventrite distinctly shorter than preepisternal elevation of mesothorax, median portion markedly differing from lateral portion in punctation and microsculpture; punctation of median portion sparse, consisting of small rounded punctures, interstices without microsculpture, shiny. Anterolateral ridges bent posteriad along lateral margin of metaventrite, concave laterally, not meeting together mesally. Anterior margin of metaventrite not crenulate. Lateral margin with additional slightly concave ridge.

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

Male genitalia. Aedeagus 0.57 mm long, parameres 1.1 × longer than phallobase. Parameres continuously narrowing apicad, bearing two long setae apically. Phallobase wide, 1.6 × longer than wide. Median lobe ca. as long as parameres, nearly parallel-sided basally, narrowing apicad in apical 0.2, apex rounded. Membranous lateral projections of median lobe absent. Gonopore present.

Etymology.

The new species is dedicated to Professor Stuart Peck (Carleton University, Canada) whose collecting trips accumulated a huge material of the West Indian Hydrophilidae , including many Oosternum specimens used for this study.

Distribution.

Oosternum pecki sp. n. is a Hispaniolan endemic species currently known only from the type locality situated in the southern part of the Dominican Republic (Barahona province) ( Fig. 61 ).

Habitat.

Based on the label data, the type specimens were collected in a remnant of the rain forest using a flight intercept 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 13 - 18. Habitus of Oosternum from West Indies. 13 - 14. Oosternum megnai sp. n., lenght = 1.49 mm (13. dorsal view, 14. lateral view). 15 - 16. Oosternum pecki sp. n., lenght = 1.50 mm (15. dorsal view, 16. lateral view). 17 - 18. Oosternum sharpi Hansen, 1999, length = 1.37 mm (17. dorsal view, 18. 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 45 - 48. Meso- and metaventrite plate. 45. Oosternum megnai 46. Oosternum pecki 47. Oosternum sharpi 48. Oosternum sp.

Figures 49 - 52. Additional diagnostic characters of West Indian Oosterum. (49) Pronotal punctation of Oosternum pecki. (50 - 52) Apical portion of elytra 50. Oosternum cercyonoides 51. Oosternum megnai 49, 52. Oosternum pecki.

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.