The Bioclastic Limestones of the “Trochitenkalk” (Upper Muschelkalk) in SW Germany

1968 ◽  
pp. 205-214 ◽  
Author(s):  
Manfred P. Gwinner ◽  
Gerhard Bachmann ◽  
Karlheinz Schäfer ◽  
Klaus Skupin
Keyword(s):  
Upper Muschelkalk

Syzygial brachials from the upper Muschelkalk (Middle Triassic, Ladinian) of Poland and their implication for an early origin of comatulid crinoids

2008 ◽  
Vol 82 (3) ◽  
pp. 634-637 ◽  
Author(s):  
Mariusz A. Salamon ◽  
Michat Zatoń ◽  
Przemysław Gorzelak
Keyword(s):  
Middle Triassic ◽  
Upper Muschelkalk ◽  
Early Origin ◽  
Irregular Arrangement

According to Ubaghs (1978), syzygies are brachial articulations in which radiating ridges and furrows on the two joint faces oppose each other rather than interlock as in symplexies. Cryptosyzygies differ from syzygies by having very short ridges that may be replaced by rows of tubercles or granules, with a tendency toward irregular arrangement and disappearance. Among Triassic crinoids, only representatives of the orders Isocrinida Sieverts-Doreck, 1952 and Comatulida Clark, 1908 had cryptosyzygial or syzygial brachial articulation, respectively. According to Rasmussen (1978), among Isocrinidae the articulations of primibrachial 1 and 2 and secundibrachial 1 and 2 were cryptosyzygial or synarthrial (but see also comments in Simms, 1988a). Among Comatulida, syzygial articulations generally occur between brachials 3 and 4 and in more distal arm parts.

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