Oosternum andersoni, 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 andersoni sp. n. Figs 1-2 19 29 39 53 61

Type-locality.

Cuba, Santiago de Cuba Province: Santiago Municipality, 20.011°N, 75.673°W, 550 m, Km 7 of the road to Gran Piedra.

Type-specimens

(144 spec.). Holotype male, dry mounted, with genitalia mounted in Euparal on a microslide pinned below the specimen. Original label: "CUBA: Santiago de Cuba: Km 7 of the road to Gran Piedra, 26.i.2012, R. Anderson leg., 20.011°N, 75.673°W, elevation 550 m [printed] / Holotype, Oosternum andersoni sp. n., Deler-Hernández & Fikáček det. 2013 [red, printed]" (NMPC). Paratypes: CUBA: Pinar del Río province, Sierra del Rosario, Rangel, ca. 15 Km S. Cinco Pesos, 30.v.1990, M. A. Ivie leg., berlese from deep log and leaf litter (2 spec., WIFP). Cienfuegos province: Cumanayagua municipality, 2 Km E of Mayarí, ca. 842 m a.s.l., 21.96651°N, 80.11497°W, 18.v.2013, R. Anderson leg (2013-017) (29 spec., NMPC); Cumanayagua municipality, uphill road to Pico San Juan, ca. 1086 m a.s.l., 21.9881°N, 80.1464°W, 19.v.2013, R. Anderson leg (2013-022) (37 spec., NMPC); Cumanayagua municipality, Aguacate, Gruta Mengoa, near of Río Cabagan, ca. 620 m a.s.l., 21°55 ’52.43” N, 80°5 ’4.60” W, 20.v.2013, R. Anderson & A. Deler-Hernández leg (CF6) (53 spec., NMPC, CMN, BMNH, SEMC, SBPC). Holguín province: Mayarí municipality, Pinarito, PN La Mensura-Piloto, ca. 410 m a.s.l., 20.41598°N, 75.82008°W, 12.v.2013, R. Anderson leg (13 spec., NMPC). Santiago de Cuba province: Km 7 of the road to Gran Piedra, ca. 550 m a.s.l., 20.011°N, 75.673°W, 26.i.2012, R. Anderson leg. (2012-007) (5 spec., BSC-E, NMPC); 23.v.2013, R. Anderson leg. (2013-031) (4 spec., NMPC).

Differential diagnosis.

Body widest ca at midlength. Lateral margin of pronotum weakly sinuate. Pronotal punctation uniform in size, moderately dense, consisting of small, 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, drop-like, 2 × longer than wide. Interstices of median part of metaventrite without microsculpture. Anterolateral ridges of metaventrite not meeting together mesally. Parameres 1.2 × longer than phallobase, bearing two short setae apically. Median lobe shorter than parameres, widely oval in shape, acute at apex. Membranous lateral projections of median lobe absent.

Description.

Habitus. Body elongate oval, gradually narrowing posteriad; total leght/total width ratio = 1.7. Length: 1.25-1.29 mm, length of holotype: 1.37 mm; width: 0.73-0.77 mm, width of holotype: 0.75 mm.

Coloration. Coloration of dorsal side brown to dark brown, elytra darker than pronotum, head dark brown. Ventral side brown. Femora and tibiae brown, tarsi, antennomeres 1-6 and mouthparts yellowish, antennal club pale reddish brown.

Head. Clypeus with sparse punctation consisting of fine rounded punctures, each puncture bearing fine decumbent seta; setae pale; interstices without microsculpture; anterior margin of clypeus slightly concave. Frons with dense punctation consisting of coarse rounded punctures, punctures of same shape medially and laterally; interstices with fine mesh-like microsculpture. Eyes moderately large. Mentum 1.8 × 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 very fine microsculpture, opaque. Submentum without poriferous disc-like fields. Maxillary palpus with palpomeres 2 and 4 ca. 1.5 × 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 weakly sinuate; with narrow marginal bead. Pronotal punctation uniform in size, moderately dense; slightly sparser than that on frons, consisting of small, rasp-like punctures, slightly sparser laterally than medially; all punctures bearing long setae; interstices without microsculpture. Transverse row of punctures on posterior margin of pronotum absent. 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. Antennal groves moderately large. Lateral margin of antennal grooves rounded.

Mesothorax. Scutellar shield bearing a few small punctures; interstices without microsculpture. Elytral series 1-5 arising basally, series 6-9 joint subbasally. Serial punctures small, transverse, sparsely arranged, with minute setae (indistinct under binocular microscope). 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, drop-like, 2 × longer than wide, widely attached to metaventrite; posterior part of preepisternal elevation slightly overlapping over anterior margin of metaventrite; median part flat; bearing sparsely arranged shallow setiferous punctures; interstices without microsculpture.

Metathorax. Metaventrite distinctly longer than preepisternal elevation of mesothorax, median portion markedly differing from lateral portion in punctation and microsculpture; punctation of median portion consisting of small rounded punctures, interstices without microsculpture, shiny. Anterolateral ridges bent posteriad along lateral margin of metaventrite, concave laterally, not meeting together and bent posteriad 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 0.5 mm long, parameres 1.2 × longer than phallobase. Parameres continuously narrowing apicad, bearing two short setae apically. Phallobase wide, 1.4 × longer than wide. Median lobe slightly shorter than parameres, widely oval in shape, slightly narrowing at apex. Membranous lateral projections of median lobe absent. Gonopore absent.

Etymology.

The new species is dedicated to our friend Robert S. Anderson (Canadian Museum of Nature, Ottawa), a very enthusiastic entomologist and collector of the type specimens.

Distribution.

Oosternum andersoni sp. n. is a Cuban endemic species currently known from the western, central and eastern parts of the island ( Fig. 61 ).

Habitat.

Most specimens were sifted from wet leaf litter in evergreen montane forests.

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.