Distinctive asymmetrical ejecta on Venus
Here is a view of an oblique impact on Venus, with accompaning butterfly ejecta pattern.
It's located at about 6 degrees S, 6 degrees W long. The USGS Venus crater database now refers to it as "Graham" with a "diameter" of 75 km (120 km x 45 km), although it is classified as "irregular".
Please reference http://www.boulder.swri.edu/~bottke/Oblique_craters/oblique.html