Article · Wikipedia archive · Last revised Jul 18, 2026

Fremontella

Fremontella is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the part of the Toyonian stage. This faunal stage was part of the Cambrian Period. Fremontella shares with the other genera of the Bristoliinae subfamily, Lochmanolenellus and Bristolia conspicuous and long curved spines on the headshield. These reach back equal to 4–5 thorax segments. The furrows that separate border, eye ridges, glabella and its lobes are distinct. The area outside of the axis of the third segment of the thorax is enlarged, and carries large trailing spine on each side.

Last revised
Jul 18, 2026
Read time
≈ 1 min
Length
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Fremontella
Temporal range:
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Arthropoda
Clade: †Artiopoda
Class: †Trilobita
Order: †Redlichiida
Family: †Biceratopsidae
Subfamily: †Bristoliinae
Genus: †Fremontella
Harrington, 1956
Species:
†F. halli
Binomial name
†Fremontella halli
(Walcott, 1910)
Synonyms
  • Wanneria halli
  • Olenellus halli
  • Olenellus alabamensis

Fremontella is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the part of the Toyonian stage. This faunal stage was part of the Cambrian Period. Fremontella shares with the other genera of the Bristoliinae subfamily, Lochmanolenellus and Bristolia conspicuous and long curved spines (called genal spines) on the headshield (or cephalon). These reach back equal to 4–5 thorax segments (measured parallel to the midline). The furrows that separate border, eye ridges, glabella and its lobes are distinct (unlike in the Biceratopsinae). The area outside of the axis (or pleural lobes) of the third segment of the thorax is enlarged, and carries large trailing spine on each side.1

Distribution

Fremontella halli has been collected in the Upper Olenellus-zone of Alabama, USA (Rome Formation, North-East of Helena).1

References

References

  1. Lieberman, B.S. (1999). "Systematic revision of the Olenelloidea (Trilobita, Cambrian)". Bulletin of the Peabody Museum of Natural History. 45: 1–150.