Sternopriscus minimus
Ordo: Coleoptera
Familia: Dytiscidae
Genus: Sternopriscus
Name
Sternopriscus minimus Lea, 1898
Type locality
Swan River, southwestern Australia.
Type material
Lectotype, male [herewith designated]: "minimus Lea TYPE Swan R. Donnybrook", "14473 Sternopriscus minimus Lea W. Australia", "LECTOTYPE Sternopriscus minimus Lea Hendrich & Watts des. 99" (SAMA). - Paralectotype, 1 female: "Swan River Donnybrook" (SAMA).
DNA Sequences
European Nucleotide Archive (ENA)
Description
Measurements: Males: TL = 1.96 - 2.00 mm, TL-H = 1.80 - 1.84 mm; width = 1.00 - 1.02 mm. Females: TL = 1.84 - 1.88 mm, TL-H = 1.70 - 1.72 mm; width = 0.96 - 1.00 mm.
Colour: Head dark brown to black with two confluent testaceous spots on front edge; pronotum dark brown to black, widely testaceous at sides and parts of disc; elytron dark brown to black with testaceous markings at side and vague ones elsewhere. Ventral surface dark brown to black, appendages and parts of abdomen testaceous, apical and middle segments of antenna and parts of metatibia darker.
Sculpture: Pronotal plicae weak, reaching to two-thirds way along pronotum, areas immediately inwards from plicae slightly depressed. Moderately strongly reticulate. Head with scattered shallow punctures, more numerous and stronger on rest of body. Prothoracic process narrow, parallel-sided, supported on a central pillar of the mesosternum well below level of metasternum, not reaching metasternum. Midline of metasternum strongly raised in front; metacoxal lines strongly raised, well separated, weakly diverging towards front.
Male: Larger. Antenna stout, segments 7 - 9 weakly expanded. Profemur with a short ridge on inside at base, inside of protibia with a slight excavation just behind middle. Basal segments of pro- and mesotarsi moderately expanded. Median lobe of aedeagus narrow, tip simple and quite broad in lateral view.
Female: Smaller. Antenna simple; basal segments of protarsus a little expanded, mesotarsus less so.
Affinities
The small size and the gap above the prosternal process are distinctive, as is the simple, though quite stout, male antenna.
Habitat
An acidophilic species. In shallow, temporary or summerdry and semi-exposed peatland sedge swamps. Only occasionally at the edge of creeks or rivers. The pool near Northcliffe (Fig. 1) was partly shaded by Melaleuca shrubs and covered with large stands of Juncus L. and dense beds of macrophytes dominated by Triglochin L. and Callitriche L.; depth up to 40 cm. Bottom consisted of sedge-filled peat (pH 5.5) twigs and rotten leaves (Hendrich 2001a, b). Most specimens were obtained from shallow and half-shaded pools in a Melaleuca blackwater swamp with few clumbs of Juncus spp. and extensive beds of macrophytes; depth up to 20 cm. Bottom consisted of sedge-filled peat (pH 5.5), twigs and rotten leaves.
Distribution
Southwestern coastal Australia, Western Australia (Watts 1978, Lawrence et al. 1987). A species only known from the most humid parts of southwestern Australia.
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.
