Sternopriscus emmae
Ordo: Coleoptera
Familia: Dytiscidae
Genus: Sternopriscus
Name
Sternopriscus emmae Hendrich & Watts, 2007
Type locality
Limestone Creek, Gregory National Park, Northern Territory, Australia.
Type material
Holotype: male, "AUSTRALIA/NT/Gregory N. P., Bullita Stock Road, Limestone Creek, 40 m, 2.7.1999, Hendrich leg./coll. Loc. 31 / 131" (SAMA). - Paratypes: Northern Territory: 93 specimens (41 male and 52 female ) with same data as holotype (ANIC, BMNH, CLH, NMW, SAMA, ZSM); 2 female, "N.T. Limestone Gorge 16.02 S 130.23 E 23-26 June 1986 m. Malipatil Operation Raleigh 1986" (NTM); Western Australia: 16 specimens (7 male and 9 female): "AUSTRALIA/WA/West Kimberley, Gibb River Road, Saddler Spring, Iminji Aboriginal Community, 350 m, 22.6.1999, Hendrich leg./coll. Loc. 20/120" (CLH).
DNA Sequences
Not yet available.
Description
Measurements: Holotype, male: TL = 3.0 mm, TL-H = 2.8 mm; width = 1.5 mm. Paratypes, males: TL = 3.0 – 3.2 mm, TL-H = 2.7 – 2.9 mm; width = 1.5 mm; females: TL = 2.9 – 3.0 mm, TL-H = 2.6 – 2.7 mm; width = 1.5 – 1.6 mm.
Colour: Head dark brown to black, area between antennal bases and small central spot near rear margin testaceous; pronotum dark brown to black, wide central transverse area and sides in front half, testaceous; elytron dark brown to black with three pairs of small testaceous spots (one lateral and one near suture, in some specimens both basal spots connected), apex testaceous; ventral surface dark testaceous, prosternum lighter. Appendages lighter; antennal segments 3 - 7 or 8 somewhat darker, tips of palpi darker.
Sculpture: Strongly reticulate, punctures relatively large, even, close, those on head weaker but well marked. Pronotal plicae well marked reaching to half way or bit more along pronotum. Edge of elytron weakly serrate, slightly widened towards apex, narrowing abruptly near apex, apex acuminate. Setae on pronotum and elytron well developed. Pronotal process rugose-punctate, ridged, sides subparallel, reaching metasternum. Midline of metasternum raised anteriorly; metacoxal lines strongly raised, weakly diverging in anterior half.
Male: Longer. Antennal segment 6 expanded, segment 7 greatly expanded, segment 8 about as wide as segment 7 but half length, lateral sloped anteriorly, segments 9 and 10 not expanded, apical segment wider than segment 10, same length as segments 9 and 10 combined. Protarsus moderately expanded; protibia bent near apex; profemur with small spine on front edge towards base. Mesotibia very weakly curved; mesotarsi with segments 2 - 3 quite strongly and asymmetrically expanded. Pro - and mesotrochanters with a thin ridge near apex, mesofemur without peg-like structure near base. Median lobe of aedeagus broad in apical half, narrowing towards base, tip complex, with well developed finger-like ventral piece.
Female: Shorter. Antennal segments not expanded; tarsi moderately and symmetrically expanded.
Affinities
Sternopriscus emmae is a member of the S. hansardii group and closely related to S. aquilonaris Hendrich & Watts, 2004, S. balkei Hendrich & Watts, 2004 and S. goldbergi Hendrich & Watts, 2004 but can be separated from these and other members of the S. hansardii group by colour, the form of the median lobe and the male antennae.
Habitat
A rheophilic species living in streams and small rivers. At Saddler Spring it occurs in a slowly flowing, exposed and deep stream, with the bank covered by stands of large Cyperaceae. All water beetles were collected in a shallow (20-30 cm) embayment of 3 sqm, among roots of emergent vegetation and plant debris. In Gregory Park all beetles were collected from two small (4-6 sqm), shallow (up to 25 cm), exposed pools in an almost dry limestone creek (Fig. 1). The bottom consisted of sand and stones, and was covered with dense mats of living and rotting Characeae. Apart from the Sternopriscus, the water beetle coenosis in the limestone creek included the following Dytiscidae: Hyphydrus decemmaculatus Wehncke, Hydroglyphus grammopterus (Zimmermann), H. leai (Guignot), Tiporus centralis (Watts), T. giuliani (Watts), T. undecimmaculatus (Clark), T. georginae Watts, and Laccophilus clarki Sharp.
Etymology
Dedicated to the senior author’s wife Emma Hendrich.
Distribution
Northern coastal Australia (Gregory National Park and Kimberley region).
Images
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References
- Hendrich, L.; Watts, C.H.S. 2007: Update of Australian Sternopriscus Sharp, 1882 with description of three new species (Coleoptera: Dytiscidae, Hydroporinae). Koleopterologische Rundschau, 77: 49–59.
