Phacopida

Walliserops trifurcatus

Order Phacopida / Suborder Phacopina / Superfamily Acastoidea / Family Acastidae / Subfamily Asteropyginae

Emsian (Early Devonian)Morocco
Walliserops trifurcatus — photo 1
Photo 1 · providing specimens; ops, Greek, eye Front of the cephalon extended into a willow-leaf-shaped trident spine with a slender shaft; three pairs of glabellar furrows; anterior glabellar lobe inflated with a distinct median furrow; occipital ring and palpebral lobes with vertical backward-curved spinules; pro- parian facial sutures; librigenae medium-wide with wide borders; fixigenae with stout genal spines and a pair of small spinules on the posterior border. Thorax of 11 segments; axial and pleural spines from segment 3 onward; pleural furrows distinct, pleural spines long. Pygidium large; 7 spined axial rings; all five pairs of pygidial pleural segments with vertical spinules; 11 long lateral pygidial spines. Holotype (Morocco; Morzadec 2001) UA13447 (Morocco; Chatterton et al., 2006) Complete dorsal exoskeleton (Morocco; Mr. Heiyanquan) Complete dorsal exoskeleton Complete dorsal exoskeleton (Morocco; Yuzhao) (Morocco; Ting Richu)
Walliserops trifurcatus — photo 2
Photo 2 · providing specimens; ops, Greek, eye Front of the cephalon extended into a willow-leaf-shaped trident spine with a slender shaft; three pairs of glabellar furrows; anterior glabellar lobe inflated with a distinct median furrow; occipital ring and palpebral lobes with vertical backward-curved spinules; pro- parian facial sutures; librigenae medium-wide with wide borders; fixigenae with stout genal spines and a pair of small spinules on the posterior border. Thorax of 11 segments; axial and pleural spines from segment 3 onward; pleural furrows distinct, pleural spines long. Pygidium large; 7 spined axial rings; all five pairs of pygidial pleural segments with vertical spinules; 11 long lateral pygidial spines. Holotype (Morocco; Morzadec 2001) UA13447 (Morocco; Chatterton et al., 2006) Complete dorsal exoskeleton (Morocco; Mr. Heiyanquan) Complete dorsal exoskeleton Complete dorsal exoskeleton (Morocco; Yuzhao) (Morocco; Ting Richu)
Walliserops trifurcatus — photo 3
Photo 3 · providing specimens; ops, Greek, eye Front of the cephalon extended into a willow-leaf-shaped trident spine with a slender shaft; three pairs of glabellar furrows; anterior glabellar lobe inflated with a distinct median furrow; occipital ring and palpebral lobes with vertical backward-curved spinules; pro- parian facial sutures; librigenae medium-wide with wide borders; fixigenae with stout genal spines and a pair of small spinules on the posterior border. Thorax of 11 segments; axial and pleural spines from segment 3 onward; pleural furrows distinct, pleural spines long. Pygidium large; 7 spined axial rings; all five pairs of pygidial pleural segments with vertical spinules; 11 long lateral pygidial spines. Holotype (Morocco; Morzadec 2001) UA13447 (Morocco; Chatterton et al., 2006) Complete dorsal exoskeleton (Morocco; Mr. Heiyanquan) Complete dorsal exoskeleton Complete dorsal exoskeleton (Morocco; Yuzhao) (Morocco; Ting Richu)
Walliserops trifurcatus — photo 4
Photo 4 · providing specimens; ops, Greek, eye Front of the cephalon extended into a willow-leaf-shaped trident spine with a slender shaft; three pairs of glabellar furrows; anterior glabellar lobe inflated with a distinct median furrow; occipital ring and palpebral lobes with vertical backward-curved spinules; pro- parian facial sutures; librigenae medium-wide with wide borders; fixigenae with stout genal spines and a pair of small spinules on the posterior border. Thorax of 11 segments; axial and pleural spines from segment 3 onward; pleural furrows distinct, pleural spines long. Pygidium large; 7 spined axial rings; all five pairs of pygidial pleural segments with vertical spinules; 11 long lateral pygidial spines. Holotype (Morocco; Morzadec 2001) UA13447 (Morocco; Chatterton et al., 2006) Complete dorsal exoskeleton (Morocco; Mr. Heiyanquan) Complete dorsal exoskeleton Complete dorsal exoskeleton (Morocco; Yuzhao) (Morocco; Ting Richu)
Walliserops trifurcatus — photo 5
Photo 5 · providing specimens; ops, Greek, eye Front of the cephalon extended into a willow-leaf-shaped trident spine with a slender shaft; three pairs of glabellar furrows; anterior glabellar lobe inflated with a distinct median furrow; occipital ring and palpebral lobes with vertical backward-curved spinules; pro- parian facial sutures; librigenae medium-wide with wide borders; fixigenae with stout genal spines and a pair of small spinules on the posterior border. Thorax of 11 segments; axial and pleural spines from segment 3 onward; pleural furrows distinct, pleural spines long. Pygidium large; 7 spined axial rings; all five pairs of pygidial pleural segments with vertical spinules; 11 long lateral pygidial spines. Holotype (Morocco; Morzadec 2001) UA13447 (Morocco; Chatterton et al., 2006) Complete dorsal exoskeleton (Morocco; Mr. Heiyanquan) Complete dorsal exoskeleton Complete dorsal exoskeleton (Morocco; Yuzhao) (Morocco; Ting Richu)
Classification
Order Phacopida / Suborder Phacopina / Superfamily Acastoidea / Family Acastidae / Subfamily Asteropyginae
Genus
Walliserops Morzadec, 2001
Genus author
Morzadec P.
Genus etymology
O. Walliser, professor at Göttingen University, in gratitude for his research on the Moroccan Devonian and for
Species
W. trifurcatus Morzadec, 2001
Species author
Morzadec P.
Species etymology
trifurcatus, three-forked, three-branched, describing the trident shape of the cephalic spine
Age
Emsian (Early Devonian)
Distribution
Morocco
Remarks
This species is the type species of the genus Walliserops, commonly known as the "long-trident trilobite" or "sea-god trilobite". The long trident spine may be a male sexual characteristic.