Neha Patil (Editor)

Macrocephalites

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Kingdom
  
Rank
  
Genus

Subclass
  
Ammonites

Superfamily
  
Stephanocerataceae

Phylum
  
Order
  
Macrocephalites sp

Similar
  
Ammonites, Oxycerites, Ataxioceras, Orthosphinctes, Ochetoceras

Macrocephalites gracilis by dtl 15


Macrocephalites is a genus of the stephanoceratacean ammonite family Macrocephalitidae, diagnostic of the Callovian stage of the Middle Jurassic. Three subgenera, Dolikephalites, Kamptokephalites, and Pleurocephalite are recognized in addition to Macrocephalites itself, with Indocephalites tentatively included as the fourth.

Contents

Macrocephalites wwwammonitesfrImages0026JPG

Macrocephalites herveyi by dtl 15


Diagnosis Macrocephalites s.s.

Macrocephalites Macrocephalites Kamptokephalites aff cossmani m

Macrocephalites itself has a strongly ribbed, involute, subglobose to discoidal shell with a somewhat small open umbilicus, compressed whorl section, higher than wide, and rounded venter. Early whorls are more strongly ribbed than later, which become smoother, ending with a smooth body chamber. Primary ribs, which emanate radially from the umbilicus, bifurcate and sometimes trifurcate mid flank and cross the venter uninterrupted. Shells grew to be large, even gigantic. Distribution is widespread.

Subgenera

Macrocephalites Stunning Cluster of Macrocephalites Ammonites For Sale 11487

Dolikephalites is similar in general form to Macrocephalites but has fine ribbing that continues to the end and is never large.

Macrocephalites Macrocephalites M verus M

Kamptokephalites is more globose than Macrocephalites' proper, with a depressed whorl section, wider than high, broadly arched venter, coarse plicate ribbing and wider umbilicus.

Macrocephalites MACROCEPHALITES sp jsdammonites

Pleurocephalites also has a broad shell with depressed whorl section and sharp ribbing that continues to the end. Primary ribs on the inner part of the whorls slope dorso-ventrally to the rear.

Indocephalites is broad and coarsely ribbed in early growth stages but becomes smoother and more compressed in the adult.

References

Macrocephalites Wikipedia


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