Carabus splendens is one of the more spectacularly coloured ground beetles of southern france. Most of the specimens are usually greenish to reddish-coppery coloured. This is a more strikingly reddish coloured individual, which was photographed at the Forêt de Sare. Seen from a lower angle, as on this image, the green colour is more prominent.
This forest is also home to the Carabus lineatus, a closely related species. Generally 'lineatus' has more pronounced blackish elytral lines, but some specimens are almost indistinguishable in the field from Carabus splendens. The only exclusive features are the longer 'wing membranes' (found under the elytral shield) from lineatus, where 'splendens' has shorter triangular reduced 'wing membranes'. The penis of the male can also reveal with certainty the species. Generally there are only few carabus species that are very difficult to distinguish in the field. The main reason for this case is that Carabus lineatus is considered as an old 'genetic fusion' between Carabus lateralis (a more southern species found in Portugal and Spain) and Carabus splendens (found in the north of Spain and southern France). Carabus lineatus has a distribution in between these two species. It reaches it's northern edge in the French Pyrenees Atlantiques. Especially in this oevrlapping range with 'splendens', lineatus shows often strongly reduced elytral lines, which makes sometimes almost indistinguishable in the field from 'splendens'.