• Corpus ID: 62885928

Connecting ring structure and its significance for classification of the orthoceratid cephalopods

  title={Connecting ring structure and its significance for classification of the orthoceratid cephalopods},
  author={Harry Mutvei},
  journal={Acta Palaeontologica Polonica},
  • H. Mutvei
  • Published 2002
  • Geology
  • Acta Palaeontologica Polonica
The connecting ring in orthoceratids is composed of two calcified layers: an outer spherulitic-prismatic and an inner calcified-perforate. The spherulitic-prismatic layer is a direct continuation of that layer in the septal neck, whereas the calcified-perforate layer is a structurally modified continuation of the nacreous layer of the septal neck. The latter layer is traversed by numerous pores which are oriented either transversally to the siphuncular surface, or have a somewhat irregularly… 

Siphuncular structures in Calciosiphonate nautiloid orders Actinocerida, Orthocerida and Barrandeocerida (Cephalopoda)

Abstract The calciosiphonate type of the connecting ring was probably present in the oldest known nautiloid cephalopods, plectronocerids, from the Late Cambrian. This type also occurs in the

Siphuncular structure in Silurian discosorid and ascocerid nautiloids (Cephalopoda) from Gotland, Sweden: implications for interpretation of mode of life and phylogeny

The connecting ring structure is studied in the discosorids Phragmoceras and Trimeroceras, as well as in the ascocerid Choanoceras. These taxa have the Nautilus type of connecting rings, composed of

Siphuncular structure in the orders Tarphycerida and Barrandeocerida (Cephalopoda: Nautiloidea)

Abstract:  The siphuncular structure is described in two Silurian taxa, Boionautilus tyrannus and Cumingsoceras complanatus, currently placed in the Tarpycerida. Tarphycerids have the Nautilus type

Siphuncular structure in the Jurassic belemnitid Megateuthis (Cephalopoda: Coleoidea)

Each septum of the phragmocone in the Jurassic belemnitid Magateuthis is composed of a thick, lamello-fibrillar, nacreous layer and a thin, chitinous layer, here termed the additional chitinous

Siphuncular structure in the Recent Nautilus, compared with that in Mesozoic nautilids and ammonoids from Madagascar

The connecting ring in the Recent Nautilus is composed of two layers: a fibrous, organic inner layer, and a porous, spherulitic-prismatic outer layer. The organic layer is an uncalcified continuation


Abstract:  Numerous plectronocerid nautiloids appear in the Upper Cambrian of China. We have restudied their siphuncular structure, first described some 20 years ago. The siphuncle is characterized

Characterization of two new superorders Nautilosiphonata and Calciosiphonata and a new order Cyrtocerinida of the subclass Nautiloidea; siphuncular structure in the Ordovician nautiloid Bathmoceras (Cephalopoda)

The structure of the siphuncular ridges in Bathmoceras is compared with that of the actinosiphonate lamellae in the Silurian oncocerid nautiloid Octamerella.

The size of the siphuncle in cephalopod evolution

It is shown that cephalopods with very high si developed strong de-coupling spaces between the outer surface of the siphuncular epithelium and the open space of the phragmocone chambers and the general trend since the end of the Palaeozoic is clearly towards a more energy efficient buoyancy regulation.

Characterization of nautiloid orders Ellesmerocerida, Oncocerida, Tarphycerida, Discosorida and Ascocerida: new superorder Multiceratoidea

On the basis of the presence of multiple muscle scars and the Nautilus type of connecting ring, the ellesmerocerids, oncocerIDS, discosorids and ascocerid orders are included in the new superorder Multiceratoidea, still unclear whether tarphycerids also belong to this superorder.



Characterization of actinoceratoid cephalopods by their siphuncular structure

The described structural type of the connecting rings, together with well-developed annular endosiphuncular deposits, are here considered as characteristic for actinoceratoids.

Siphuncular structure in Ordovician endocerid cephalopods

Exceptionally well-preserved shells of the endocerids Dideroceras wahlenbergi (Foord, 1887), Anthoceras vaginatum (Schlotheim, 1820), and Suecoceras barrandei (Dewitz, 1880) from phosphatized Early

Siphuncular structure in a Silurian narthecoceratid nautiloid cephalopod from the Island of Gotland

Abstract The material of Donacoceras gotlandense n.sp. (Ortho-cerida, Fam. Narthecoceratidae), embedded in the Llandoverian Lower Visby mudstone on the Island of Gotland, Sweden, consists mainly of

Muscle-attachment impressions in some Paleozoic nautiloid cephalopods

Muscle-attachment impressions are described for the first time from representatives of the nautiloid suborders Oncoceratina (Oncoceras sp., Beloitoceras sp., Diestoceras sp.) Ascoceratina

Conch Ultrastructure and Septal Neck Ontogeny of the Belemnite Conobelus (Duvaliidae) from the Valanginian of the Crimea (Black Sea)

Several exceptionally well-preserved phragmocones of the belemnite Conobelus, with approximately 20 chambers preserved, were collected from the Valanginian of the Crimean Peninsula (Black Sea). The

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.

Attachment of the Body to the Shell in Ammonoids

One of the most intriguing paleobiological problems in ammonoids is to interpret the organization of their muscular system in order to obtain a better understanding of their locomotion and,

Muscles and attachment of the body to the shell in embryos and adults of Nautilus belauensis (Cephalopoda). American Museum novitates ; no. 3059

There are two pairs of retractor muscles in Nautilus, the cephalic and hyponome retractors, which correspond to the two pairsOfephridia, gills, and atria, suggesting that Nauts may retain some evidence of metamerism.

A Review of Volkhovian and Kundan (Arenig-Llanvirn) Nautiloids from Sweden

Well preserved nautiloid cephalopods dominate diverse macrofossil assemblages in early and mid Ordovician platform carbonates across Sweden (the so-called ‘Orthoceratite Limestone’ lithofacies).

Topotactic reaction of aragonite to hydroxyapatite

The orthorhombic aragonite structure can be described by a pseudohexagonal cell with a = 9.38, c = 5.74 Ä and y = 117°, the base of which resembles tha t of apat i te (a = 9.43, c = 6.88, y = 120°)