Ptychopariida

Euloma orientalis

Order Ptychopariida / Suborder Ptychopariina / Superfamily Ptychoparioidea / Family Eulomidae

Tremadocian (Early Ordovician)Hunan

Euloma orientalis — photo 1 — Photo 1 · Type specimen figures (Hunan; Liu Yiren Pygidium and hypostome specimens 1982) (Hunan; Peng 1990) Form with axial spine (Hunan; Peng 1990) Form without axial Complete dorsal exoskeleton spine (Hunan; (Hunan; Guodong) Peng 1990)

Euloma orientalis — photo 2 — Photo 2 · Type specimen figures (Hunan; Liu Yiren Pygidium and hypostome specimens 1982) (Hunan; Peng 1990) Form with axial spine (Hunan; Peng 1990) Form without axial Complete dorsal exoskeleton spine (Hunan; (Hunan; Guodong) Peng 1990)

Euloma orientalis — photo 3 — Photo 3 · Type specimen figures (Hunan; Liu Yiren Pygidium and hypostome specimens 1982) (Hunan; Peng 1990) Form with axial spine (Hunan; Peng 1990) Form without axial Complete dorsal exoskeleton spine (Hunan; (Hunan; Guodong) Peng 1990)

Euloma orientalis — photo 4 — Photo 4 · Type specimen figures (Hunan; Liu Yiren Pygidium and hypostome specimens 1982) (Hunan; Peng 1990) Form with axial spine (Hunan; Peng 1990) Form without axial Complete dorsal exoskeleton spine (Hunan; (Hunan; Guodong) Peng 1990)

Euloma orientalis — photo 5 — Photo 5 · Type specimen figures (Hunan; Liu Yiren Pygidium and hypostome specimens 1982) (Hunan; Peng 1990) Form with axial spine (Hunan; Peng 1990) Form without axial Complete dorsal exoskeleton spine (Hunan; (Hunan; Guodong) Peng 1990)

Euloma orientalis — photo 6 — Photo 6 · Type specimen figures (Hunan; Liu Yiren Pygidium and hypostome specimens 1982) (Hunan; Peng 1990) Form with axial spine (Hunan; Peng 1990) Form without axial Complete dorsal exoskeleton spine (Hunan; (Hunan; Guodong) Peng 1990)

Euloma orientalis — photo 7 — Photo 7 · Type specimen figures (Hunan; Liu Yiren Pygidium and hypostome specimens 1982) (Hunan; Peng 1990) Form with axial spine (Hunan; Peng 1990) Form without axial Complete dorsal exoskeleton spine (Hunan; (Hunan; Guodong) Peng 1990)

Euloma orientalis — photo 8 — Photo 8 · Type specimen figures (Hunan; Liu Yiren Pygidium and hypostome specimens 1982) (Hunan; Peng 1990) Form with axial spine (Hunan; Peng 1990) Form without axial Complete dorsal exoskeleton spine (Hunan; (Hunan; Guodong) Peng 1990)

Euloma orientalis — photo 9 — Photo 9 · Type specimen figures (Hunan; Liu Yiren Pygidium and hypostome specimens 1982) (Hunan; Peng 1990) Form with axial spine (Hunan; Peng 1990) Form without axial Complete dorsal exoskeleton spine (Hunan; (Hunan; Guodong) Peng 1990)

Classification

Order Ptychopariida / Suborder Ptychopariina / Superfamily Ptychoparioidea / Family Eulomidae

Genus

Euloma Angelin, 1854

Genus author

Angelin N. P.

Genus etymology

eu, good, or a shortening of eucallus (beautiful); lom, the border of a robe

Species

E. orientalis Liu in Zhou et al., 1977

Species author

Liu Yiren

Species etymology

orientalis, Latin, oriental, referring to the Chinese locality

Age

Tremadocian (Early Ordovician)

Distribution

Hunan

Diagnosis

Cranidium subquadrate; glabella trapezoidal, slightly constricted anteriorly, with 3 pairs of lateral glabellar furrows; preglabellar field long; eyes large; eye ridges distinct. Thorax of 13 segments; segment 6 with or without an axial spine; pleural furrows wide and deep, pleural spines short. Pygidium small and wide, subrhomboidal; with two axial rings and a terminal piece; the pleural furrow opposite the first axial ring distinct.

Remarks

This species occurs in two forms, with and without an axial spine, possibly representing sexual dimorphism.