Ptychopariida

Acrocephalina sp.

Order Ptychopariida / Suborder Ptychopariina / Superfamily Ptychoparioidea / Family Dokimocephalidae

Stage 10 (Furongian, Cambrian) to Tremadocian (Early Ordovician)Hunan

Acrocephalina sp. — photo 1 — Photo 1 · Complete dorsal exoskeleton with enlargements of various sclerites (Hunan; Weidingzhong Guchong) Specimen co-occurring with an Asian olenid (Hunan; Complete dorsal exoskeleton Y.W) (Hunan; Lixia)

Acrocephalina sp. — photo 2 — Photo 2 · Complete dorsal exoskeleton with enlargements of various sclerites (Hunan; Weidingzhong Guchong) Specimen co-occurring with an Asian olenid (Hunan; Complete dorsal exoskeleton Y.W) (Hunan; Lixia)

Acrocephalina sp. — photo 3 — Photo 3 · Complete dorsal exoskeleton with enlargements of various sclerites (Hunan; Weidingzhong Guchong) Specimen co-occurring with an Asian olenid (Hunan; Complete dorsal exoskeleton Y.W) (Hunan; Lixia)

Classification

Order Ptychopariida / Suborder Ptychopariina / Superfamily Ptychoparioidea / Family Dokimocephalidae

Genus

Acrocephalina Troedsson, 1937

Genus author

Troedsson C. T.

Genus etymology

acro, Greek, extreme, tip; cephal-, head

Species

Acrocephalina sp.

Species author

Species etymology

Age

Stage 10 (Furongian, Cambrian) to Tremadocian (Early Ordovician)

Distribution

Hunan

Diagnosis

Cephalon with fine tubercles, semi-elliptical apart from the spine-like structures; anterior part of the cranidium protruding into a long anterior spine; glabella subtrapezoidal with two oblique glabellar furrows, of which S1 connects the dorsal and occipital (S0) furrows; occipital spine present; eyes relatively small; eye ridges distinct; librigenae narrow and long with knife-point genal angles, a genal spine arising from the mid-lower part of the border, first inclined upward then curving downward, reaching more than twice the body length. Thorax of 10 segments; axis narrow; pleural lobes wide with wide deep pleural furrows, pleural ends changing from pointed to blunt posteriorly, upper and lower margins of pleurae nodose; from segment 5 onward, each pleural segment bears a distinctly raised ridge-like structure running in an arc from the margin through the pygidium to the pygidial axis. Pygidium small, semi-elliptical; border wide.