Order: CORYNEXOCHIDA Kobayashi, 1935
Family: STYGINIDAE Vogdes, 1890
Subfamily: SCUTELLUINAE Richter and Richter, 1955
Genus: PARALEJURUS Hawle and Corda, 1847
Diagnosis
The body of Paralejurus is strongly vaulted. The glabella reaches the frontal border. There are shallow glabellar furrows and the fixigenae are narrow. The axis is wider than the pleural field. On the pygidium the median rib is bifurcate.
Occurence
There are many species of Paralejurus. We will discuss the ones who occur in Morocco below. Paralejurus occurs in the Pragian and Emsian.
Recognizing Paralejurus species
Used with permission:
Feist, R., Lerosey-Aubril, R., Johnson, R., 2010
Paralejurus brongniarti
Barande, 1846 (Pragian – Plain north-northeast of Mdouer-el-Kebir, southeast of Foum Zguid, Morocco)
Used with permission: Schraut and Feist, 2004
Paralejurus bohemicus
Šnajdr, 1960 (Pragian – Jebel Issoumour, Mäder, south-southeast of Alnif, Morocco)
P. bohemicus has no genal spines.
The pygidium is domed without edge.
Very typical for this form is the triangual formed pygidial axis.
Schraut (2000) described Paralejurus elayounensis. This one is very similar to P. bohemicus. It may be different because it does not have the granular structure like P. bohemicus. The outline is also a bit narrower, but P. bohemicus tends to become narrower when growing. So this species (and relationship) is still open for discussion.
Used with permission: Schraut and Feist, 2004
Paralejurus spatuliformis
Schraut & Feist, 2004 (Pragian – Jbel Oufatène, Mäder, Morocco)
P. spatuliformis is different from the other Paralejurus forms because of its tongue like pygidium. The other forms have a pygidium that is much more vaulted.
Used with permission: Schraut and Feist, 2004
Paralejurus rehamnanus
G. Alberti, 1970 (upper Emsian – Jebel Oufatène, Mäder, Morocco)
The glabellar edge of P. rehamnanus is straigher than in other species.
The genal spines are strong
The pygidial axis is almost non existant.
Used with permission: Schraut and Feist, 2004
Paralejurus tenuistriatus
Schraut & Feist, 2004 (Pragian – Jbel Oufatène, Mäder, Morocco)
P. tenuistriatus has strong genal spines
Unlike P. rehamnanus it has a more curved glabellar edge
The pygidial axis is trapezoidal in form.
References
Feist, R., Lerosey-Aubril, R., Johnson, R., 2010. Coaptative devices, enrollment, and life habits in Paralejurus, a particular case in scutelluid trilobites. Palaeobiodiversity and Palaeoenvironments 90(2):125-137
Schraut, G., Feist, R., 2004. The Devonian styginid trilobite Paralejurus, with new data from Spain and Morocco. Journal of Paleontology 78(4):709-722