Black rhinoceroses ("Diceros bicornis") develop iron overload. These are referred to a separate subspecies ("Diceros bicornis ladoensis") by some authorities. The biggest threat towards the subspecies "Diceros bicornis occidentalis" is illegal poaching. Even heavier prey, such as black rhinoceros ("Diceros bicornis"), have been killed by crocodiles. This subspecies was named "Diceros bicornis longipes" by Ludwig Zukowsky in 1949. The south-central black rhinoceros ("Diceros bicornis minor") is a subspecies of the black rhinoceros.