View source for Sternopriscus balkei

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==Taxonavigation==
Ordo: [http://species.wikimedia.org/wiki/Coleoptera Coleoptera]<br />
Familia: [[Dytiscidae]] <br />
Genus: ''[[Sternopriscus]]''


==Name==
''Sternopriscus balkei'' {{aut|Hendrich & Watts, 2004}}

==Type locality==
Intermittent creek near Mount Borradaile, Northern Territory, Australia.

==Type material==
Holotype: male, "N.T. 5 km SE Mt. Borradaile stn 8/10/98/ C. Watts" (SAMA). - Paratypes: Northern Territory: 4 male and 10 female with the same data as holotype; 6 male and 6 female, "Australia N.T./ Kakadu N.P., Jim Jim District, Jim Jim Falls Camping Area, Jim Jim Creek, 60 m, 26. & 27.10. 1996 S 13°16. 218' E 132°49. 276', L. Hendrich leg. / Lok. 2." (CLH, NMW); 2 male and 1 female, "Australia, N.T./ Kakadu N.P., Mary River District, 3 km ESE Gunlom Camping Area. South Alligator River, 50 m, 2.11.1996 S 13°27. 276' E 132°26. 268', L. Hendrich leg. / Lok. 14." (CLH); 1 female, "12.25'S 132.56'E Red Lilly Lagoon, N.T. 3.xi.72, edge of water in billabong, E Britton" (ANIC); 1 female, "12.23'S 132.56'E 7 km NW. by N. of Mt. Cahills Crossing, East Alligator River, N.T. 9.vi.73, Upton & Feehan" (ANIC); 1 male "Nourlangie ck. 20 km SSW Jabiru N.T. 11/10/98 C. Watts" (SAMA); 1 female "6 km SE Mt Borradaile N.T. 8/19/98 C. Watts" (SAMA); 1 male, "NT 1 km W Gubara Kakadu NP 29/1/99 C. Watts" (SAMA). Western Australia: 6 exs., "AUSTRALIA/ WA/ East Kimberley, East Gibb River Road, Barnett River Gorge, 450 m, 19.6.1999, Hendrich leg./coll. Loc.17/ 117" (CLH); 3 exs., "AUSTRALIA/ WA/ East Kimberley, Mitchell Plateau, Surveyors Pool, 150 m, 17.6.1999, Hendrich leg./coll. Loc. 12/ 112" (CLH); 1 ex., "AUSTRALIA/ WA/ East Kimberley, East Gibb River Road, Galvans Gorge, 420 m, 21.6.1999, Hendrich leg./coll. Loc. 19/ 119" (CLH).

==DNA Sequences==
[http://www.ebi.ac.uk/ena/data/view/CBY46374 European Nucleotide Archive (ENA)]

==Description==
Measurements: Holotype, male: TL = 3.20 mm, TL-H = 2.80 mm; width = 1.60 mm. Paratypes, males: TL = 2.92 - 3.20 mm, TL-H = 2.60 - 2.80 mm; width = 1.48 - 1.60 mm; females: 2.60 - 2.92 mm, TL-H = 2.36 - 2.60 mm; width = 1.32 - 1.60 mm.

Colour: Dark brown to black with only occasional lighter areas on dorsal surface, appendages dark testaceous, antennal segments 5 - 7 bit darker than others, tips of palpi darker. 

Sculpture: Strongly reticulate, punctures relatively strong, evenly spaced, close, those on head small but well marked. Edge of elytron quite strongly serrate towards apex, elytron slightly widened towards apex, abruptly narrowing near apex, apex moderately acuminate. Pronotal plica well marked, reaching to about half way along pronotum. Pronotal process robust, subparallel, reaching metasternum, curved in lateral view. Midline of metasternum ridged anteriorly; metacoxal lines strongly raised, moderately separated, weakly divergent in front half.

Male: Larger. Antennal segment 6 weakly expanded, segment 7 strongly expanded, segment 8 not quite as wide and about half length of segment 7, segments 9 and 10 normal, apical segment same width as segment 10 a little shorter than segments 9 and 10 combined. Pro- and mesotrochanters with sharp thin ridge near apex. Protarsus moderately expanded; protibia curved; profemur with small spine on front edge towards base. Mesofemur with small peg-like spine at base adjacent to raised ridge on mesotrochantera; basal three segments of mesotarsi moderately asymmetrically expanded. Median lobe of aedeagus broad in apical half, narrowing towards base, tip complex, with well develop finger-like ventral piece.

Female: Smaller. Appendages simple, tarsi moderately expanded, somewhat less so than in male, symmetrical.

==Affinities==
A member of the ''S. hansardi'' group. Dorsal surface black except for one or two small lateral testaceous spots on elytron, strongly punctate, pronotal plicae strong, antennae in male with the three apical segments little modified, well developed finger-like ventral extension to the median lobe of the aedeagus.

==Habitat==
A rheophilic species. In the Northern Territory the species was collected in exposed, deep (60 - 100cm), broad (up to 6 m), low-gradient parts of rivers with bottoms consisting of stones, gravel and sand, and with a thin layer of organic debris. The riverine forest was dominated by Swamp Bloodwood or Anbamberre. Most of the specimens were collected in mats of floating grass and roots along the edge of the water. A few were obtained from small, semi-shaded, flood-zone pools with coarse sand and gravel and the bottom covered with a few decaying leaves in an otherwise mostly dry area of the Jim Jim Creek river bed. At Gunlom the species was collected among leaf litter in protected, shallow, shaded (Giant Bamboo, ''Eucalyptus'') embayments along the sandy bank of the South Alligator River. At Gubara the species was collected in small, shaded pools in the flood-zone of a monsoon rainforest stream dominated by Native Nutmeg, ''Calophyllum'', ''Horsfieldia'' and Antwolbon Trees. The water was clear, up to 20 cm deep, the bottom gravely and sandy with a thick layer of decaying leaves. In the dry season the Black Jungle Spring is a spring fed, slow flowing, shallow (up to 30 cm deep) stream, rich in organic debris and partly shaded by ''Pandanus'' trees with a bottom of gravel and coarse sand, partly covered with a thick layer of dark organic silt. At Mt. Borradaile the species was collected from small, shallow, semi-shaded rock-pools in a river bed with a substrate of sand and decaying leaves.

==Etymology==
Dedicated to Dr. Michael Balke.

==Distribution==
Northern coastal Australia (Kimberley Region, Kakadu National Park and Alligator Rivers).

==Images==
{{Gallery | lines=2 | width=400

|1= File:Sternopriscus balkei Northern Territory Litchfield NP creek near Wanggi Falls.JPG
|2= '''Figure 1.''' Habitat of ''Sternopriscus balkei''. Australia, Northern Territory, Litchfield Nationalpark, creek near Wanggi Falls. (Photo: Lars Hendrich)
}}

==References==
* {{aut|Hendrich, L.}}; {{aut|Watts, C.H.S.}} 2004: Taxonomic revision of the Australian genus ''Sternopriscus'' Sharp, 1882 (Coleoptera: Dytiscidae, Hydroporinae). ''Koleopterologische Rundschau'', '''74''': 75–142.

==Online resources==