Family Phacopidae
Subfamilies: Phacopinae
Genera: Geesops, Hypsipariops, Liolophops, Nyterops, Omegops, Pedinopariops, Phacops.
Phacopids are chief components of the Belgian Middle Devonian trilobite fauna. They have been lumped in the past with Phacops latifrons and sometimes with Phacops potieri. In the 1970s the late Wolfgang Struve (then Senckenberg Museum Frankfurt) commenced a series of noteworthy contributions to the knowledge of Phacopidae mainly in the Ardennes-Eifel region and Morocco, essentially erecting genera that are close to Phacops (e.g. Pedinopariops, Geesops, Nyterops, Liolophops, Hypsipariops, Cultrops, Burtonops, Teichertops). After thirty years, it appears that Struve's concept probably has some weak aspects but that it is generally well-defined and can be followed (at least) for many Rhenish taxa. In the Ardennes, Geesops and Pedinopariops are probably commonest in the lower and middle Eifelian while Nyterops dominates in the upper Eifelian and Lower Givetian.
Key to telling phacopids apart is to have specimens which are not tectonically deformed. The extent to which the cephalon is vaulted, tubercles, granules, size and position of eyes, number of lenses in the eyes, presence or absence of a border ridge, are all indicators of the genus and species that they belong to.
List of species
Pragian
- Phacopinae gen. & sp. indet.
Eifelian
- Geesops sp.
- Geesops sparsinodosus gallicus STRUVE, 1982
- Phacops sartenaeri STRUVE, 1985
- Phacops cf. imitator STRUVE, 1970
- Nyterops hollandi VAN VIERSEN, 2007
- Hypsipariops spp.
- Liolophops sp.
- Pedinopariops spp.
Givetian
- Nyterops cf. hollandi VAN VIERSEN, 2007