Spirula—a window to the embryonic development of ammonoids? Morphological and molecular indications for a palaeontological hypothesis

  title={Spirula—a window to the embryonic development of ammonoids? Morphological and molecular indications for a palaeontological hypothesis},
  author={Kerstin Martina Warnke and Helmut Keupp},
  • K. Warnke, H. Keupp
  • Published 26 May 2005
  • Biology, Geography, Environmental Science
  • Facies
Nautilus is not suitable as a model organism to infer biological functions, embryonic development, or mode of life in ammonoids. A brief review of the available morphological data is given and molecular data are added to discuss the usefulness of Spirula as a biological proxy for ammonoids. Indeed, there are many morphological hints indicating that Spirula could be a useful model organism for approaching the embryonic development of ammonoids. The molecular data seem to support this hypothesis… 

Pelagic palaeoecology: the importance of recent constraints on ammonoid palaeobiology and life history

Various lines of evidence suggest that different groups of ammonoids had quite different ecologies, but shell shape alone can only give upper constraints on ammonoid capabilities, a matter that needs to be considered when interpreting their diversity and evolutionary history.

Homology problems in cephalopod morphology: deceptive (dis)similarities between different types of ‘caecum’

  • D. Fuchs
  • Biology
    Swiss Journal of Palaeontology
  • 2019
To conclude, the spiruloid protoconch (including caecum) has been derived either from a belemnitid or diplobelid protoconh, which is structurally closer to the bactritoid/ammonoid protconch than to the Spirula caecu.

Ammonoid Habitats and Life History

The current knowledge about the ammonoid/habitat relation is reviewed and in part newly interpreted. The autecology of ammonoids, such as ontogeny and habitat, based on morphological and geochemical

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

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, and the potential fecundity and brooding behaviour of prolobites is hypothesized using the examples of post spawning egg care in Recent coleoids.

Cephalopod embryonic shells as a tool to reconstruct reproductive strategies in extinct taxa

An exhaustive study of existing data on the relationship between egg size and maximum size of embryonic shells in 42 species of extant cephalopods demonstrated that these values are approximately

New size data on the enigmatic Spirula spirula (Decabrachia, suborder Spirulina), on a global geographic scale

  • A. Lukeneder
  • Environmental Science, Geography
    Swiss Journal of Palaeontology
  • 2015
Morphologic and geographic data suggest a geographically induced size differentiation within S. spirula, and preliminary findings on conchs mirror the known (from soft parts) existence of two sexual dimorphs in Spirula.

Isotopic analysis of the life history of the enigmatic squid Spirula spirula, with implications for studies of fossil cephalopods

The results of this study have important implications for understanding ancestors of S. spirula, such as belemnites, in terms of the constraints on equilibrium precipitation of shell carbonate, sought in terms in paleoenvironmental studies.

A preliminary estimate of the trophic position of the deep-water ram’s horn squid Spirula spirula based on the nitrogen isotopic composition of amino acids

A new method (amino acid nitrogen isotopic analysis) was applied to estimate the trophic position of S. spirula specimens captured off Suriname, as well as three cuttlefish Sepia species, with a calcified chambered shell from the shallower water.

Traumatic events in the life of the deep-sea cephalopod mollusc, the coleoid Spirula spirula



Analysis of a Carboniferous embryonic ammonoid assemblage implications for ammonoid embryology

An embryonic ammonoid assemblage was discovered in a carbonate concretion recovered from a dysoxic, relatively offshore marine shale of Virgilian (Upper Pennsylvanian) age in Kansas, USA. The

The mode of life in ammonoids

The following structural features clearly indicate that ammonoid shells were adapted to withstand considerably higher hydrostatic pressures thanNautilus shells: (1) the corrugated and marginally

Biology of early life stages in cephalopod molluscs.

Advancing Research on Living and Fossil Cephalopods

also applied to exceptionally preserved Conobelus (Duvaliidae) collected by L.A. Doguzhaeva and collaborators from the Valanginian of the Crimean Peninsula. Their study reveals differences in

Nautilus—a poor model for the function and behavior of ammonoids?

Reexamination of the evidence indicates that static stability should not play a role in the swimming of ammonoids with long body chambers, and functional arguments suggest that a coleoid-like swimming mechanism should have evolved prior to the loss of the body chamber in coleoids.

Major divisions of the Cephalopoda

Factual and theoretical evidence combine to suggest that many of the features of the Dibranchiata may have developed in their ancestors included in the Nautiloidea, and that many in Nautilus are derived, or possibly connected with, crucial changes in mode of life now known to have occurred in its ancestry.

The Position of the Ammonoidea within the Cephalopoda

It is still worth the effort to state more precisely the position of the Ammonoidea within the Coleoidesa clade (= Neocephalopoda) using a cladistic approach.

Juvenile goniatite survival strategies following Devonian extinction events

  • M. House
  • Geography, Environmental Science
    Geological Society, London, Special Publications
  • 1996
Abstract During the Devonian there is a correlation between certain periods of sedimentary perturbations, often associated with hypoxia, and extinction events in the evolution of the goniatite and

A Late Carboniferous Spirulid Coleoid from ahe Southern Mid-Continent (USA)

Ultrastructural study of a longiconic cephalopod, formerly described as B. postremus, reveals that the shell wall, consisting of two prismatic layers and lacking a nacreous layer, differs strongly from that of bactritoids, and is considered to be the earliest known member of the order Spirulida.