Large beetle by pond for ID

[djeyewater]

I saw this large beetle (about 4-5cm) on the edge of a pond in some gardens I visited last week. Unfortunately when I went to photograph it, it buried its head in some rocks on the edge of the pond amongst all the algae. Any ideas on a possible ID?



Thanks

Dave

[Dogghound]

Its Dytiscus marginalis .

[Matt Smith]

It is one of the 4 UK species on Dytiscus with a yellow line at the rear of the thorax. D.marginalis is the commonest of these 4, but without a look at the bases of the hind legs it is impossible to get a definative ID from these photos.

[djeyewater]

Thanks for the help!

Dave

[Ukwildlifeo]

Cant help witht he species but with Dytiscus marginalis the ridges on the wing cases mean its a feamle, which may be so for other species of the genus too.