Hebediscidae

Hebediscidae is a family of trilobites belonging to the order Agnostida that lived during the Lower Cambrian (Atdabanian to Toyonian). They are small or very small, and have a thorax of two or three segments. The Hebediscidae include five genera (see box).

Hebediscidae Temporal range: Lower Cambrian PreꞒ Ꞓ O S D C P T J K Pg N
Tchernyshevioides ninae
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Clade:	†Artiopoda
Class:	†Trilobita (?)
Order:	†Agnostida
Suborder:	†Eodiscina
Superfamily:	†Eodiscoidea
Family:	†Hebediscidae Kobayashi, 1944
Genera[1]
Delgadella Dicerodiscus Hebediscus Luvsanodiscus Limbadiscus Neopagetina Parapagetia Tchernyshevioides
Synonyms
Delgadoiinae Pagetiellinae Dicerodiscinae

Taxonomy

The Hebediscidae probably descended from the Tsunyidiscidae and gave rise to the Weymouthiidae.^[2]

Description

Like all Agnostida, the Hebediscidae are diminutive and the headshield (or cephalon) and tailshield (or pygidium) are of approximately the same size (or isopygous) and outline. In the Hebediscidae, the central raised area of the cephalon (or glabella) is wide at its rear end, has parallel sides or tapers forward, and without transverse glabellar furrows, although the lobes may be apparent if they are expanded. A three segment thorax is known in Hebediscus, Delgadella and Tchernyshevioides. The pygidium has a wide, tapering axis of more than four segments.^[1]