Walliserops hammi Trilobite

Description: This trilobite is a member of the Order Phacopida, Family Acastidae from the Devonian deposits of Ziguilma, Morocco known commercially as the Short Fork Trident Comura. The Chatterton and Brett had erected the genus Parabolops, with the long-forked trident being Parabolops neptunis and the short-forked Parabolops hammi (see my other examples for a fine long-forked example), but the genus remains Waliiserops at present. Some think the differences may be the result of sexual dimorphism. Radical differences between the sexes are common in Arthropods (see some of the scarab beetles, for example). However, there are some half dozen known variants, so unless trilobites had a panoply of sexes the theory does not hold up to scrutiny. Whatever you call it, this is a spectacular example. Other than the distinctive trident and the genals ALL spines have been prepared freestanding on the cephalon as well as those on the axial lobes, making for a dramatic display with OVER FIFTY freestanding spines (I apologize for the less-than-esthetic photography while still in the shipping container, but discretion was the better part of valor with all the spines). The color variation is natural and due to differential absorption of minerals during diagenesis. See my other specimens for an example prepared totally freestanding.

Reference: Palaeontograhica Canadiana, No 25, 2006, pp 33-36