Agnostida

Trinodus tardus

Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Metagnostidae

Ordovician, Late Ordovician KatianHubei, Yunnan; Czech Republic

Trinodus tardus — photo 1 — Photo 1 · Neotype specimen NML16534 (Czech Republic; Budil et al., Reconstruction (Budil et al., Muscle scars preserved (Czech 2011) 2011) Republic; Budil et al., 2011) Longitudinally compressed Complete dorsal shield Complete dorsal shield specimen (Yunnan; Lixia) (Yunnan; Tang Shi) (Yunnan; Baishui)

Trinodus tardus — photo 2 — Photo 2 · Neotype specimen NML16534 (Czech Republic; Budil et al., Reconstruction (Budil et al., Muscle scars preserved (Czech 2011) 2011) Republic; Budil et al., 2011) Longitudinally compressed Complete dorsal shield Complete dorsal shield specimen (Yunnan; Lixia) (Yunnan; Tang Shi) (Yunnan; Baishui)

Trinodus tardus — photo 3 — Photo 3 · Neotype specimen NML16534 (Czech Republic; Budil et al., Reconstruction (Budil et al., Muscle scars preserved (Czech 2011) 2011) Republic; Budil et al., 2011) Longitudinally compressed Complete dorsal shield Complete dorsal shield specimen (Yunnan; Lixia) (Yunnan; Tang Shi) (Yunnan; Baishui)

Trinodus tardus — photo 4 — Photo 4 · Neotype specimen NML16534 (Czech Republic; Budil et al., Reconstruction (Budil et al., Muscle scars preserved (Czech 2011) 2011) Republic; Budil et al., 2011) Longitudinally compressed Complete dorsal shield Complete dorsal shield specimen (Yunnan; Lixia) (Yunnan; Tang Shi) (Yunnan; Baishui)

Trinodus tardus — photo 5 — Photo 5 · Neotype specimen NML16534 (Czech Republic; Budil et al., Reconstruction (Budil et al., Muscle scars preserved (Czech 2011) 2011) Republic; Budil et al., 2011) Longitudinally compressed Complete dorsal shield Complete dorsal shield specimen (Yunnan; Lixia) (Yunnan; Tang Shi) (Yunnan; Baishui)

Trinodus tardus — photo 6 — Photo 6 · Neotype specimen NML16534 (Czech Republic; Budil et al., Reconstruction (Budil et al., Muscle scars preserved (Czech 2011) 2011) Republic; Budil et al., 2011) Longitudinally compressed Complete dorsal shield Complete dorsal shield specimen (Yunnan; Lixia) (Yunnan; Tang Shi) (Yunnan; Baishui)

Classification

Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Metagnostidae

Genus

Trinodus

Genus author

M'Coy F.

Genus etymology

tri-, three; nodus, Latin, node, joint.

Species

T. tardus (Barrande, 1846)

Species author

Barrande J.

Species etymology

tardus, slow, sluggish.

Age

Ordovician, Late Ordovician Katian

Distribution

Hubei, Yunnan; Czech Republic

Synonyms

Battus tardus; Agnostus glabratus; Agnostus tardus; Agnostus(Arthrorhachis)tardus; Arthrorhachis tarda; Trinodus subtardus; Trinodus corrugatus; Trinodus insuetus

Diagnosis

Cephalon semicircular; glabellar furrows almost effaced, slightly constricted medially, with small glabellar node at the anterior third; basal lobe small; dorsal furrow broad and deep; border narrow; border furrow broad and deep. Pygidium subsquare; pygidial axis short, divided into three rings, with a long axial node dividing the first two rings into three parts; postaxial field long.