Kendallina

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Phylum:Arthropoda
Clade:Artiopoda
Class:Trilobita
Order:Asaphida
Kendallina
Temporal range: Upper Cambrian, 492.5–488.3 Ma
Kendallina crassitesta, 18 mm
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Arthropoda
Clade: Artiopoda
Class: Trilobita
Order: Asaphida
Family: Parabolinoididae
Genus: Kendallina
Berg, 1953
Species
  • K. eryon (Hall, 1863) (type) = Conocephalites eryon
  • K. biforota Berg, 1953
  • K. crassitesta Westrop, 1963
Synonyms

Kendallia Berg, 1953, non Evermann & Shaw, 1927 (jr. synonym of Hemiculter, a carp)

Kendallina is a genus of parabolinoidid trilobite[1] with an inverted egg-shaped outline, a wide headshield, small eyes, small deflected spines, 12 thorax segments and a small, short tailshield. It lived during the Late Cambrian in what are today Canada and the United States.

The outline of the exoskeleton Kendallina is inverted egg-shaped, with a wide rectangular headshield (or cephalon) about twice as wide as long. The well-defined central raised area (or glabella), excluding the backward occipital ring, is almost as wide as long, moderately convex, truncate-tapering, with 3 pairs of shallow to obsolete lateral furrows. The occipital ring is well defined. The distance between the glabella and the border (or preglabellar field) is ±14× as long as the glabella. Kendallina has small eyes, 18× as long as the cephalon, which are positioned near the front of the glabella and about half as far out as the glabella is wide. The remaining parts of the cephalon, called fixed and free cheeks (or fixigenae and librigenae) are flat. The fracture lines (or sutures) that in moulting separate the librigenae from the fixigenae are divergent just in front of the eyes, becoming parallel near the border furrow and strongly convergent at the margin. From the back of the eyes the sutures are straight, diverging outward and backward at approximately 45°, cutting the posterior margin well within the inner bend of the spine (or opisthoparian sutures). The articulating middle part of the body (or thorax) has 12 segments. The anteriormost segment gradually narrows into a sideward directed point, while further to the back the segments are rounded with a short, outward deflected spine at back of their outer tips. The small tailshield (or pygidium) is about 13× as wide as the cephalon, narrowly transverse about 3× wider than long. Its axis is about the same width as pleural fields to each side, and has up to 3 axial rings and a terminal and almost reaches the margin. Up to 4 pleural segments with obsolete interpleural grooves and shallow pleural furrows. The posterior margin is smooth or has one pair of minute spines. The surface has fine granules or is smooth.[2]

Taxonomy

Distribution

References

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