L. unguispinus is roughly long. Its frontal appendages are short with a large first endite bearing several spines and alternating endites thereafter. The neck is prominent with four segments. The first flap pair is hypertrophied and paddle-shaped, with the following pairs decreasing sharply in size and a tail fan composed of three blade-like flap pairs. Remarkably, the nervous system of
L. unguispinus is preserved in detail, showing that radiodont frontal appendages are protocerebral like the antennae of
velvet worms, showing the two structures derive from the same source. In addition, as the
labrum also seems to be protocerebral, it also likely derives from the same structures, providing a possible answer to the
arthropod head problem. The first flap in this species is not much wider than the rest, unlike in
L. unguispinus, alongside the flaps having transverse lines interpreted as strengthening rays, another trait unique to this species. The trunk is divided into three lobes (giving this species its name) by prominent furrows, with the central region being more raised than the lateral ones. == Etymology ==