Swiss Journal of Geosciences

, Volume 103, Issue 3, pp 475–494

Size distribution of the Late Devonian ammonoid Prolobites: indication for possible mass spawning events

  • Sonny Alexander Walton
  • Dieter Korn
  • Christian Klug

DOI: 10.1007/s00015-010-0036-y

Cite this article as:
Walton, S.A., Korn, D. & Klug, C. Swiss J Geosci (2010) 103: 475. doi:10.1007/s00015-010-0036-y


Worldwide, the ammonoid genus Prolobites is only known from a few localities, and from these fossil beds almost all of the specimens are adults as shown by the presence of a terminal growth stage. This is in marked contrast to the co-occurring ammonoid genera such as Sporadoceras, Prionoceras, and Platyclymenia. Size distribution of specimens of Prolobites from three studied localities show that, unlike in the co-occurring ammonoid species, most of the material belongs to adult individuals. The morphometric analysis of Prolobites delphinus (Sandberger & Sandberger 1851) demonstrates the intraspecific variability including variants with elliptical coiling and that dimorphism is not detectable. The Prolobites material shows close resemblance to spawning populations of Recent coleoids such as the squid Todarodes filippovae Adam1975. Possible mass spawning events are discussed in the context of the size distribution and limited geographic range of Prolobites. Finally, the potential fecundity and brooding behaviour of Prolobites is hypothesized using the examples of post spawning egg care in Recent coleoids.


Ammonoidea Coleoidea Morphometry Late Devonian Famennian Spawning 



Senckenberg Museum, Frankfurt a. M., Germany


Cephalopod collection of the Museum für Naturkunde Berlin (the collections of Franz Ademmer, Werner Bottke, and Harald Simon are incorporated here)

Copyright information

© Swiss Geological Society 2010

Authors and Affiliations

  • Sonny Alexander Walton
    • 1
  • Dieter Korn
    • 1
  • Christian Klug
    • 2
  1. 1.Museum für NaturkundeLeibniz Institute, Humboldt University BerlinBerlinGermany
  2. 2.Paläontologisches Institut und Museum der Universität ZürichZürichSwitzerland

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