Corynexochida

Blackwelderia sp. 1

Order Corynexochida / Suborder Leiostegiina / Superfamily Dameselloidea / Family Damesellidae / Subfamily Damesellinae

Guzhangian (Miaolingian, Cambrian)Shandong, Liaoning and other parts of North China
Blackwelderia sp. 1 — photo 1
Photo 1 · specimens Early literature specimen (Shandong; Walcott Pygidium specimen Librigenae and pleural spines 1913) (Shandong; Baishui) with denticles (enlarged detail below) Complete dorsal exoskeleton Enrolled dorsal exoskeleton (Shandong; Yicheng) (Shandong; Huakai Fugui) Dorsal exoskeleton lacking pygidium, with denticles Complete dorsal exoskeleton preserved on the pleural spines (Shandong; Yicheng) (Shandong; Yimeng Shanren)
Blackwelderia sp. 1 — photo 2
Photo 2 · specimens Early literature specimen (Shandong; Walcott Pygidium specimen Librigenae and pleural spines 1913) (Shandong; Baishui) with denticles (enlarged detail below) Complete dorsal exoskeleton Enrolled dorsal exoskeleton (Shandong; Yicheng) (Shandong; Huakai Fugui) Dorsal exoskeleton lacking pygidium, with denticles Complete dorsal exoskeleton preserved on the pleural spines (Shandong; Yicheng) (Shandong; Yimeng Shanren)
Blackwelderia sp. 1 — photo 3
Photo 3 · specimens Early literature specimen (Shandong; Walcott Pygidium specimen Librigenae and pleural spines 1913) (Shandong; Baishui) with denticles (enlarged detail below) Complete dorsal exoskeleton Enrolled dorsal exoskeleton (Shandong; Yicheng) (Shandong; Huakai Fugui) Dorsal exoskeleton lacking pygidium, with denticles Complete dorsal exoskeleton preserved on the pleural spines (Shandong; Yicheng) (Shandong; Yimeng Shanren)
Blackwelderia sp. 1 — photo 4
Photo 4 · specimens Early literature specimen (Shandong; Walcott Pygidium specimen Librigenae and pleural spines 1913) (Shandong; Baishui) with denticles (enlarged detail below) Complete dorsal exoskeleton Enrolled dorsal exoskeleton (Shandong; Yicheng) (Shandong; Huakai Fugui) Dorsal exoskeleton lacking pygidium, with denticles Complete dorsal exoskeleton preserved on the pleural spines (Shandong; Yicheng) (Shandong; Yimeng Shanren)
Blackwelderia sp. 1 — photo 5
Photo 5 · specimens Early literature specimen (Shandong; Walcott Pygidium specimen Librigenae and pleural spines 1913) (Shandong; Baishui) with denticles (enlarged detail below) Complete dorsal exoskeleton Enrolled dorsal exoskeleton (Shandong; Yicheng) (Shandong; Huakai Fugui) Dorsal exoskeleton lacking pygidium, with denticles Complete dorsal exoskeleton preserved on the pleural spines (Shandong; Yicheng) (Shandong; Yimeng Shanren)
Blackwelderia sp. 1 — photo 6
Photo 6 · specimens Early literature specimen (Shandong; Walcott Pygidium specimen Librigenae and pleural spines 1913) (Shandong; Baishui) with denticles (enlarged detail below) Complete dorsal exoskeleton Enrolled dorsal exoskeleton (Shandong; Yicheng) (Shandong; Huakai Fugui) Dorsal exoskeleton lacking pygidium, with denticles Complete dorsal exoskeleton preserved on the pleural spines (Shandong; Yicheng) (Shandong; Yimeng Shanren)
Blackwelderia sp. 1 — photo 7
Photo 7 · specimens Early literature specimen (Shandong; Walcott Pygidium specimen Librigenae and pleural spines 1913) (Shandong; Baishui) with denticles (enlarged detail below) Complete dorsal exoskeleton Enrolled dorsal exoskeleton (Shandong; Yicheng) (Shandong; Huakai Fugui) Dorsal exoskeleton lacking pygidium, with denticles Complete dorsal exoskeleton preserved on the pleural spines (Shandong; Yicheng) (Shandong; Yimeng Shanren)
Blackwelderia sp. 1 — photo 8
Photo 8 · specimens Early literature specimen (Shandong; Walcott Pygidium specimen Librigenae and pleural spines 1913) (Shandong; Baishui) with denticles (enlarged detail below) Complete dorsal exoskeleton Enrolled dorsal exoskeleton (Shandong; Yicheng) (Shandong; Huakai Fugui) Dorsal exoskeleton lacking pygidium, with denticles Complete dorsal exoskeleton preserved on the pleural spines (Shandong; Yicheng) (Shandong; Yimeng Shanren)
Blackwelderia sp. 1 — photo 9
Photo 9 · specimens Early literature specimen (Shandong; Walcott Pygidium specimen Librigenae and pleural spines 1913) (Shandong; Baishui) with denticles (enlarged detail below) Complete dorsal exoskeleton Enrolled dorsal exoskeleton (Shandong; Yicheng) (Shandong; Huakai Fugui) Dorsal exoskeleton lacking pygidium, with denticles Complete dorsal exoskeleton preserved on the pleural spines (Shandong; Yicheng) (Shandong; Yimeng Shanren)
Blackwelderia sp. 1 — photo 10
Photo 10 · specimens Early literature specimen (Shandong; Walcott Pygidium specimen Librigenae and pleural spines 1913) (Shandong; Baishui) with denticles (enlarged detail below) Complete dorsal exoskeleton Enrolled dorsal exoskeleton (Shandong; Yicheng) (Shandong; Huakai Fugui) Dorsal exoskeleton lacking pygidium, with denticles Complete dorsal exoskeleton preserved on the pleural spines (Shandong; Yicheng) (Shandong; Yimeng Shanren)
Classification
Order Corynexochida / Suborder Leiostegiina / Superfamily Dameselloidea / Family Damesellidae / Subfamily Damesellinae
Genus
Blackwelderia Walcott, 1906
Genus author
Walcott C. D.
Genus etymology
Blackwelder, a surname, referring to E. Blackwelder, an early-20th-century collector of North China trilobite
Species
Blackwelderia sp. 1
Species author
/
Species etymology
/
Age
Guzhangian (Miaolingian, Cambrian)
Distribution
Shandong, Liaoning and other parts of North China
Diagnosis
Dorsal shield verrucose. Cranidium wide; glabella truncate-conical with four pairs of glabellar furrows, L1 inverted V-shaped; occipital ring with a median node; fixigenae strongly convex; palpebral lobes raised above the glabella; preglabellar field depressed; anterior border erect; posterior margin of fixigenae denticulate; librigenae with rather long genal spines bearing denticles. Thorax of 12 segments; axis narrower than pleurae; pleural furrows transverse, pleural spines long with denticles. Pygidial axis long-conical; border narrow with 7 pairs of spines, the first pair large and long. Since Walcott 1913 this species has long been misidentified as Blackwelderia sinensis. The main differences are:
Remarks
the posterior margin of the cephalon bears many spines, the anterior border is narrower, the palpebral area is more elevated, the glabella has an inverted V-shaped L1, the genal and pleural spines are densely covered with small denticles, and the first pair of pygidial spines is exceptionally large.