Scutelluinae

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Scutelluinae
Scheme from Bojoscutellum paliferum (Beyrich, 1845). A) Cephalon B) Hypostome C) Pygidium D) Thickness of the pygidium

Scheme from Bojoscutellum paliferum (Beyrich, 1845).
A) Cephalon B) Hypostome C) Pygidium D) Thickness of the pygidium

Temporal occurrence
Lower Ordovician to Upper Devonian ( Middle Frasnium )
460.9 to 385.3 million years
Locations
  • Worldwide
Systematics
Arthropod (arthropoda)
Trilobites (Trilobita)
Corynexochida
Illaenina
Styginidae
Scutelluinae
Scientific name
Scutelluinae
Richter & Richter , 1955

Scutelluinae is a trilobite subfamily of the styginid trilobites and was first introduced in 1955.

features

Cranidium of the cephalon.
Or: the neck ring (Occipitalring)
SO: neck groove (Occipitalfurche)
ll: Lateral Nackenlobus
L1-L3: Lateral neck lobes
FL: front Glabellalobus
S1-S3: Lateral Gabellafurchen
lfg: Longitudiale Glabellafurche
he: eyes ribs
mn: Middle node in the Glabellafurche
ma: protrusion of Neck ring
fi: Elevation on the fixed cheeks
fs: Dorsally located part of the thorax support

Cephalon : The neck ring can have extensions (ma) into the neck furrow. The first furrow (S1) is semicircular, slightly indented or horseshoe-shaped. There may be a nodule (ma) in this furrow. The second furrow (S2) is very short and not connected to the side. The third furrow (S3) is longer and can be connected to the side. The glabella furrows (S1-S3) can be connected to one another by longitudinal furrows (lgf). On the opposite side of the first lobe (L1) of the glabella there is an elevation (fi) on the fixed cheeks. The surface of the cephalon is very smooth and can be convexly curved.

Thorax : The thorax consists of ten segments. The first segment is supported and smaller than the rest. The furrowless pleuras are concave and end in a tip that is bent backwards.

Pygidium : The spindle on the tail shield has an annular furrow in older species. In older species it is divided into three praises. The tail shield usually has seven and rarely six to eight lateral pairs of ribs and a central rib in the extension of the spindle, which can be divided below. In two genera the ribs end in points and in one genus ( Paralejurus ) the ribs are very weak and fused.

Occurrence

The animals of the Scutelluinae lived from the Lower Ordovician to Upper Devonian . The last documented trilobite of this subfamily lived in the central frasnium . The last trilobite species of this subfamily all belong to the genus Scutellum , which can be detected for around 55 million years.

Genera (selection)

Web links

Commons : Scutelluinae  - collection of images, videos and audio files

Individual evidence

  1. ^ A b c Harry B. Whittington : Siluro-Devonian Scutelluinae (Trilobita) from the Czech Republic; morphology and classification . In: Journal of Paleontology ; May 1999; v. 73; No. 3; Pp. 414-430