Marrolithus

Marrolithus; Temporal range:
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Clade:	†Artiopoda
Class:	†Trilobita
Order:	†Asaphida
Family:	†Trinucleidae
Genus:	†Marrolithus; Bancroft, 1929
Species
	Marrolithus bureaui Oehlert, 1895 Marrolithus orthogonius Dean, 1967

Marrolithus is an extinct genus of trinucleid trilobite that lived during the Ordovician period.¹

Palaeobiology

Ontogeny

During the meraspid period of ontogeny, the glabella of Marrolithus bureaui became compressed. During this ontogenetic stage, the species also developed a pronounced sub-quadrangular cephalic outline. The alae disappeared later on in development.²

References

"Marrolithus". Paleobiology Database. Retrieved 11 June 2026.
Delabroye, Aurelien; Cronier, Catherine (July 2008). "Ontogeny of an Ordovician Trinucleid (Trilobita) from Armorica, France: A Morphometric Approach". Journal of Paleontology. 82 (4): 800–810. doi:10.1666/07-084.1. ISSN 0022-3360. Retrieved 11 June 2026 – via Cambridge Core.

[1] "Marrolithus". Paleobiology Database. Retrieved 11 June 2026.

[2] Delabroye, Aurelien; Cronier, Catherine (July 2008). "Ontogeny of an Ordovician Trinucleid (Trilobita) from Armorica, France: A Morphometric Approach". Journal of Paleontology. 82 (4): 800–810. doi:10.1666/07-084.1. ISSN 0022-3360. Retrieved 11 June 2026 – via Cambridge Core.

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