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Janiceps
Classification
Phylum:
Brachiopoda
Class:
Rhynchonellata
Order:
Athyridida
Superfamily:
Athyridoidea
Family:
Athyrididae
Formal Genus Name and Reference:
Janiceps FRECH, 1901, p. 551
Type Species:
Spirigera peracuta Stache, 1878, p. 152, SD Schuchert & LEVENE, 1929a, p. 70
Images
(Click to enlarge in a new window)
Fig. 1045, $3 a-t .*$ J. peracuta (Stache), upper Changhsingian, southern Alps, $a-c$, dorsal, ventral, and posterior views, Monte Croce di Cornelico, MGBW 3797-b, Stache Collection, $d-f$, dorsal, ventral, and lateral views, Monte Croce di Cornelico, MGBW 3797-a, Stache Collection, x2$, $g-t$, transverse serial sections 0.50, 1.55, 3.55, 4.50, 4.95, 5.30, 5.55, 5.80, 6.40, $7.45, 10.70, 11.25, 12.55, 14.05 \\mathrm{~mm}$ from ventral umbo, Val Brutta, MDSGF J06 (new, photographs and serial sections courtesy of R. Posenato).’
Synonyms
Geographic Distribution
Italy (southern Alps), Armenia
Age Range
Beginning Stage in Treatise Usage:
Upper Permian (Changhsingian)
Beginning International Stage:
Changhsingian
Fraction Up In Beginning Stage:
0
Beginning Date:
254.24
Ending Stage in Treatise Usage:
Upper Permian (Changhsingian)
Ending International Stage:
Changhsingian
Fraction Up In Ending Stage:
100
Ending Date:
251.9
Description
Medium to large, subequally biconvex, usually triangular shells with maximum width at anterior third of shell, very close to front, more rarely subrhomboidal to pentagonal, each valve usually bearing 2 pair of rounded unequal folds starting at apex and widening moderately anteriorly, ventral cardinal area more or less defined, dental plates thin and short, may be buried in secondary shell material that is strongly developed in umbonal cavities, low dental flanges may support teeth anteriorly, [The outline of some Janiceps species resembles that of young Comelicania (e.g., POSENATO, 1998). But, until better preserved specimens of Janiceps can be studied, this genus is provisionally included in the Spirigerellinae due to its adult external morphology and internal characters. The relationship between Janiceps and Comelicania and their taxonomic position within the Athyrididae requires revision.]
References
Museum or Author Information
Classification
Phylum:
Brachiopoda
Class:
Rhynchonellata
Order:
Athyridida
Superfamily:
Athyridoidea
Family:
Athyrididae
Formal Genus Name and Reference:
Janiceps FRECH, 1901, p. 551
Type Species:
Spirigera peracuta Stache, 1878, p. 152, SD Schuchert & LEVENE, 1929a, p. 70
Images
(Click to enlarge in a new window)
Fig. 1045, $3 a-t .*$ J. peracuta (Stache), upper Changhsingian, southern Alps, $a-c$, dorsal, ventral, and posterior views, Monte Croce di Cornelico, MGBW 3797-b, Stache Collection, $d-f$, dorsal, ventral, and lateral views, Monte Croce di Cornelico, MGBW 3797-a, Stache Collection, x2$, $g-t$, transverse serial sections 0.50, 1.55, 3.55, 4.50, 4.95, 5.30, 5.55, 5.80, 6.40, $7.45, 10.70, 11.25, 12.55, 14.05 \\mathrm{~mm}$ from ventral umbo, Val Brutta, MDSGF J06 (new, photographs and serial sections courtesy of R. Posenato).’
Synonyms
Geographic Distribution
Italy (southern Alps), Armenia
Age Range
Beginning Stage in Treatise Usage:
Upper Permian (Changhsingian)
Beginning International Stage:
Changhsingian
Fraction Up In Beginning Stage:
0
Beginning Date:
254.24
Ending Stage in Treatise Usage:
Upper Permian (Changhsingian)
Ending International Stage:
Changhsingian
Fraction Up In Ending Stage:
100
Ending Date:
251.9
Description
Medium to large, subequally biconvex, usually triangular shells with maximum width at anterior third of shell, very close to front, more rarely subrhomboidal to pentagonal, each valve usually bearing 2 pair of rounded unequal folds starting at apex and widening moderately anteriorly, ventral cardinal area more or less defined, dental plates thin and short, may be buried in secondary shell material that is strongly developed in umbonal cavities, low dental flanges may support teeth anteriorly, [The outline of some Janiceps species resembles that of young Comelicania (e.g., POSENATO, 1998). But, until better preserved specimens of Janiceps can be studied, this genus is provisionally included in the Spirigerellinae due to its adult external morphology and internal characters. The relationship between Janiceps and Comelicania and their taxonomic position within the Athyrididae requires revision.]