Sternopriscus marginatus
Ordo: Coleoptera
Familia: Dytiscidae
Genus: Sternopriscus
Name
Sternopriscus marginatus Watts, 1978
Type locality
Margaret River, Western Australia.
Type material
Holotype: male, "Margaret River Oct’31 S.W.A.", "Australia Harvard Exped. Darlington", "Museum of Comparative Zoology", "Holotype" (ANIC). Paratypes: 6 specimens with the same data as holotype [4 exs. in ANIC, 2 exs. in MCZ (WATTS 1978)]; 1 male and 1 female, "Bridgetown, SW Aust Nov 9.1931", "Australia Harvard Exped. Darlington", "Museum of Comparative Zoology" [2 exs. with same data in MCZ (Watts 1978)] (SAMA); 1 male, "Pemberton, W.A., Oct’ 31, Australia Harvard Exped. Darlington", "Museum of Comparative Zoology" (SAMA). Syntype: male, "Bridgetown, SW Aust Nov 9.193", "Australia Harvard Exped. Darlington", "Museum of Comparative Zoology" (SAMA).
DNA Sequences
European Nucleotide Archive (ENA)
Description
Measurements: Males: TL = 3.40 - 3.52 mm, TL-H = 3.08 - 3.52 mm; width = 1.76 - 1.84 mm. Females: TL = 3.08 - 3.28 mm, TL-H = 2.76 - 3.00 mm; width = 1.60 - 1.68 mm.
Colour: Head testaceous, hind angles brown; pronotum testaceous, front and rear edges diffusely darker in middle; elytron diffusely mottled testaceous and brown; ventral surface brown with darker and lighter patches, appendages lighter except segments 5 - 7 of antenna which are darker.
Sculpture: Reticulate. Punctures on head well marked, of moderate size and density, rest of body moderately strongly rugose-punctate. Pronotal plicae almost straight, well marked, reaching to about two thirds way along pronotum. Midline of metasternum strongly keeled but not raised in front to meet prothoracic process. Prothoracic process robust, subparallel, rugose-punctate, keeled, curved in lateral view, reaching metasternum. Metacoxal lines raised to metasternum, weakly diverging towards front.
Male: Larger. Antennal segment 7 moderately expanded, segments 8 - 11 progressively less so, segments 7 and 8 same length, segments 7 - 10 concave and spongose beneath, apical segment same width but longer than penultimate. Apical segment of labial palpus thick moderately bifid. Basal three segments of protarsus moderately expanded; protibia weakly notched near base; profemur simple; protrochanter with sharp ridge at apex. Mesotarsi moderately expanded; mesotibia almost straight; mesofemur elongate, relatively dense moderately long setae along inner edges, mesotrochanter with similar setae. Median lobe of aedeagus elongate, thin, tip expanded, spoon-shaped, tip weakly bifid [illustration in Watts 1978 is of a damaged specimen].
Female: Smaller. Appendages simple, labial palpus weaker; pronotum a little constricted behind.
Affinities
A western Australian species, readily separable from all other Sternopriscus by the broadly flanged elytra in both sexes. Males can be separated from the more common and slightly smaller S. browni by the simple mesotarsi and simply modified antennae.
Habitat
A rheophilic species which inhabits, small creeks, clear, slow moving rivers and pools of intermittent forest streams, usually in places with little submerged vegetation and sandy or gravely bottom.
Distribution
Southwestern coastal Australia, Western Australia (Watts 1978, Lawrence et al. 1987). South and southwest of a line from Bunbury to the Stirling Ranges.
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.
