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Tricrepicephalus
Classification
Phylum:
Arthropoda
Subphylum:
Trilobitomorpha
Class:
Trilobita
Order:
Ptychopariida
Suborder:
Ptychopariina
Superfamily:
Crepicephalacea
Family:
Tricrepicephalidea
Formal Genus Name and Reference:
Tricrepicephalus KOBAYASHI, 1935
Type Species:
Arionellus (Bathyurus) texanus SHUMARD, 1861
Images
(Click to enlarge in a new window)
Fig. 187,4. ·T. texanus (SHUMARD), Tex.; 4a, exoskel., × 0.9, 4b, cran. profile, × 1, 4c, pyg. profile, × 1
Synonyms
Paracrepicephalus
Geographic Distribution
N.Am.-S.Am.
Age Range
Beginning Stage in Treatise Usage:
Low.Upper Cambrian(Dresbach.)
Beginning International Stage:
Guzhangian
Fraction Up In Beginning Stage:
50
Beginning Date:
498.75
Ending Stage in Treatise Usage:
Low.Upper Cambrian(Dresbach.)
Ending International Stage:
Paibian
Fraction Up In Ending Stage:
73.3
Ending Date:
494.95
Description
Eyes behind midlevel of glabella, lateral furrows shallow, with 3 evenly spaced, round or elliptical pits in anterior border furrow, palpebral furrows shallow, eye ridges narrow, with occipital spine or node, fixigenae horizontal, with palpebral area more than 0.5 of glabellar width, posterior area long (tr.). Thorax of 12 segments. Pygidium quadrate, axis convex, wider than pleural regions, more than 0.7 of length, with 3 axial rings, 3 broad, low pleurae forming into a long hollow, rounded spine at posterolateral corners, narrow border along posterior continues under spines along sides (235, 316).
References
Museum or Author Information
Classification
Phylum:
Arthropoda
Subphylum:
Trilobitomorpha
Class:
Trilobita
Order:
Ptychopariida
Suborder:
Ptychopariina
Superfamily:
Crepicephalacea
Family:
Tricrepicephalidea
Formal Genus Name and Reference:
Tricrepicephalus KOBAYASHI, 1935
Type Species:
Arionellus (Bathyurus) texanus SHUMARD, 1861
Images
(Click to enlarge in a new window)
Fig. 187,4. ·T. texanus (SHUMARD), Tex.; 4a, exoskel., × 0.9, 4b, cran. profile, × 1, 4c, pyg. profile, × 1
Synonyms
Paracrepicephalus
Geographic Distribution
N.Am.-S.Am.
Age Range
Beginning Stage in Treatise Usage:
Low.Upper Cambrian(Dresbach.)
Beginning International Stage:
Guzhangian
Fraction Up In Beginning Stage:
50
Beginning Date:
498.75
Ending Stage in Treatise Usage:
Low.Upper Cambrian(Dresbach.)
Ending International Stage:
Paibian
Fraction Up In Ending Stage:
73.3
Ending Date:
494.95
Description
Eyes behind midlevel of glabella, lateral furrows shallow, with 3 evenly spaced, round or elliptical pits in anterior border furrow, palpebral furrows shallow, eye ridges narrow, with occipital spine or node, fixigenae horizontal, with palpebral area more than 0.5 of glabellar width, posterior area long (tr.). Thorax of 12 segments. Pygidium quadrate, axis convex, wider than pleural regions, more than 0.7 of length, with 3 axial rings, 3 broad, low pleurae forming into a long hollow, rounded spine at posterolateral corners, narrow border along posterior continues under spines along sides (235, 316).