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Holotrachelus
Classification
Phylum:
Arthropoda
Subphylum:
Trilobitomorpha
Class:
Trilobita
Order:
Ptychopariida
Suborder:
Illaenina
Superfamily:
Holotrachelacea
Family:
Holotrachelidae
Formal Genus Name and Reference:
Holotrachelus Linnarsson in TÖRNQUIST, 1919
Type Species:
Homalonotus punctillosus TÖRNQUIST, 1884
Images
(Click to enlarge in a new window)
Fig. 289. *H. punctillostrs (Törnquist), a, c, ceph., dorsal, ventral, x1.5, b, 8th thoracic seg. and pyg., x4.5, d, hypostoma, x1.5 (489)"
Synonyms
Geographic Distribution
N. Eu. (Ire.-Eng.-Swed.)-Sib. (KuznetskKirghiz)-N.Am.(Que.
Age Range
Beginning Stage in Treatise Usage:
U. Ord.
Beginning International Stage:
Sandbian
Fraction Up In Beginning Stage:
0
Beginning Date:
458.18
Ending Stage in Treatise Usage:
U. Ord.
Ending International Stage:
Hirnantian
Fraction Up In Ending Stage:
100
Ending Date:
443.07
Description
Super-family/Family characteristics (mono-genus!) = Cephalon large, surrounded by distinct border; cephalic axis long, rather strongly convex, narrowing forward, smooth, without glabellar or occipital furrows; facial sutures opisthoparian. Rostral shield wide (tr.) anteriorly, strongly narrowing backward, hindmost part forming a very short rostral doublure; hypostoma with strong lateral and middle furrows, posterior lobe with prominent rounded boss, anterior wings triangular. Thorax with 8 segments (in type genus); pleurae with distinct diagonal pleural furrows and well-developed facets. Pygidium (in type genus) with gently convex axis, composed of 3 rings and terminal; pleural fields without border, bearing 4 pairs of flattened tergites, anterior pairs carrying pleural furrows, boundaries between pygidial tergites sharp and suturelike. Surface ornamented by terrace lines and small pits. [Assignment to Illaenina is very uncertain.]
References
Museum or Author Information
Classification
Phylum:
Arthropoda
Subphylum:
Trilobitomorpha
Class:
Trilobita
Order:
Ptychopariida
Suborder:
Illaenina
Superfamily:
Holotrachelacea
Family:
Holotrachelidae
Formal Genus Name and Reference:
Holotrachelus Linnarsson in TÖRNQUIST, 1919
Type Species:
Homalonotus punctillosus TÖRNQUIST, 1884
Images
(Click to enlarge in a new window)
Fig. 289. *H. punctillostrs (Törnquist), a, c, ceph., dorsal, ventral, x1.5, b, 8th thoracic seg. and pyg., x4.5, d, hypostoma, x1.5 (489)"
Synonyms
Geographic Distribution
N. Eu. (Ire.-Eng.-Swed.)-Sib. (KuznetskKirghiz)-N.Am.(Que.
Age Range
Beginning Stage in Treatise Usage:
U. Ord.
Beginning International Stage:
Sandbian
Fraction Up In Beginning Stage:
0
Beginning Date:
458.18
Ending Stage in Treatise Usage:
U. Ord.
Ending International Stage:
Hirnantian
Fraction Up In Ending Stage:
100
Ending Date:
443.07
Description
Super-family/Family characteristics (mono-genus!) = Cephalon large, surrounded by distinct border; cephalic axis long, rather strongly convex, narrowing forward, smooth, without glabellar or occipital furrows; facial sutures opisthoparian. Rostral shield wide (tr.) anteriorly, strongly narrowing backward, hindmost part forming a very short rostral doublure; hypostoma with strong lateral and middle furrows, posterior lobe with prominent rounded boss, anterior wings triangular. Thorax with 8 segments (in type genus); pleurae with distinct diagonal pleural furrows and well-developed facets. Pygidium (in type genus) with gently convex axis, composed of 3 rings and terminal; pleural fields without border, bearing 4 pairs of flattened tergites, anterior pairs carrying pleural furrows, boundaries between pygidial tergites sharp and suturelike. Surface ornamented by terrace lines and small pits. [Assignment to Illaenina is very uncertain.]