Sternopriscus tasmanicus
Ordo: Coleoptera
Familia: Dytiscidae
Genus: Sternopriscus
Name
Sternopriscus tasmanicus Sharp, 1882
Type locality
Tasmania
Type material
Holotype male: "Tasmania", "Holotype", "Tasmania 1134 Tasmania", "Sternopriscus tasmanicus Sharp Type" (BMNH).
DNA Sequences
European Nucleotide Archive (ENA)
Description
Measurements: Specimens from mainland Australia. Males: TL = 2.68 - 2.86 mm, TL-H = 2.40 - 2.60 mm; width = 1.32 - 1.36 mm. Females: TL = 2.48 - 2.72 mm, TL-H = 2.28 - 2.52 mm; width = 1.28 - 1.40 mm. Specimens from Tasmania. Males: TL = 2.92 - 3.08 mm, TL-H = 2.68 - 2.80 mm; width = 1.40 - 1.44 mm. Females: TL = 2.72 - 2.76 mm, TL-H = 2.40 - 2.60 mm; width = 1.30 - 1.40 mm.
Colour: Head black, front margin and a basal spot testaceous; pronotum black, broadly testaceous at sides; elytron mottled dark brown and testaceous; ventral surface dark brown to black, sides of prosternum and appendages lighter, antenna darker apically.
Sculpture: Head with very strong reticulation and moderately dense, shallow punctures, rest of body reticulate and strongly and closely rugose-punctate. Pronotal plicae well marked, reaching to about half way along pronotum, with well-marked depression between them. Prothoracic process robust, subparallel, strongly punctate, not reaching metasternum. Metacoxal lines raised, moderately diverging anteriorly.
Male: Larger. Antenna stout, segments 7 - 10 a little expanded, apical segment greatly expanded, its inner edge straight, outer edge curved, apex pointed. Protarsus greatly expanded; protibia expanded, curved, with a small basal indentation on inside; profemur slightly ridged on inside near base. Mesotarsus robust a little expanded and a little elongate; mesotibia a little curved. Median lobe of aedeagus simple, parallel-sided, slightly bulbous towards apex.
Female: Smaller. Edge of pronotum a little sinuate; antenna relatively stout, segments simple; basal segments of pro- and mesotarsi moderately expanded.
Affinities
A member of the S. tasmanicus complex. From S. alpinus it differs in having extensive testaceous areas on the pronotum and the medial lobe of the aedeagus somewhat bulbous apically rather than flat as in S. alpinus. It is more difficult to distinguish from S. wehnckei but the more pointed shape of the apical segment of the antennae will separate them. Specimens from Tasmania appear, on average, to be larger and possibly more strongly sculptured but otherwise differ little from mainland specimens. As in most of the S. tarsalis group the extent of testaceous colour on the head and pronotum is highly variable.
Habitat
Found mainly in open ponds (Fig. 2), coastal swamps and farm dams, only occasionally at the edges of creeks and rivers. Tolerates slightly saline water.
Distribution
Southeastern coastal Australia, southern Gulfs, lower altituides up to sea level of Tasmania, South Australia and Victoria (Watts 1978, Lawrence et al. 1987).
Images
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References
- Hendrich, L.; Watts, C.H.S. 2004: Taxonomic revision of the Australian genus Sternopriscus Sharp, 1882 (Coleoptera: Dytiscidae, Hydroporinae). Koleopterologische Rundschau, 74: 75–142.
