Archaeocyathan knowledge base (Cambrian)

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Sekwicyathus

Sekwicyathus HANDFIELD, 1971

Specimen-type: Sekwicyathus nahanniensis holotype, HANDFIELD, 1971, p. 34 , pl. 2, fig. 5

Systematics:
Order: AJACICYATHIDA R. Bedford& J. Bedford, 1939
Suborder: AJACICYATHINA R. Bedford& J. Bedford, 1939
Superfamily: ETHMOPHYLLOIDEA Okulitch, 1937
Family: FALLOCYATHIDAE Rozanov, 1969

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Outer wall

• Shape of carcass perforations openings (OW/SW) : ?
• Direction of carcass canals tubes (OW/SW) : Horizontal to upwardly opening
• Presence of carcass external plates: outer wall or single wall (OW/SW) : None
• Origin of carcass canals (OW/SW) : Within the intervallum
• Type of carcass perforations: outer wall or single wall (OW/SW) : Canals
• Presence of carcass bumps: outer wall or single wall (OW/SW) : None
• Presence of stipules (OW/SW) : Present
• Shape of morphological tubes (OW/SW) : Inverted-V shaped
• Structure of outer carcass wall (OW/SW) : Carcass wall well defined
• Shape of carcass canals tubes (OW/SW) : Curved
• Type of additional sheath (OW/SW) : None
• Rows number of carcass perforations per intersept (OW/SW) : More than 2 rows per intersept only
• Subdivision of carcass perforations openings (OW/SW) : Without subdivision ; Incipient pore subdivision

Inner wall

• Shape of carcass perforations openings (IW) : Simple
• Rows number of carcass pores per intertabula (IW) : No tabula
• Type of carcass perforations: inner wall (IW) : Pores
• Building of carcass perforations (IW) : Without participation of vertical structures
• Presence of carcass external plates: inner carcass wall (IW) : None (external plates and/or inner wall)
• Shape of morphological tubes (IW) : None
• Structure of inner carcass wall (IW) : Carcass wall well defined
• Type of additional sheath (IW) : None
• Presence of stipules (IW) : None
• Rows number of carcass perforations per intersept (IW) : More than 2 rows per intersept only
• Subdivision of carcass perforations openings (IW) : Without subdivision

Intervallum

• Presence of intervallar cells : None
• Type of links between intervallar structures : None
• Presence of vertical intervallar structures : Present
• Presence of tabulae : none
• Type of vertical intervallar structures : Septa
• Repartition of vertical intervallar structures pores : Sparsely porous
• Porosity type of vertical intervallar structures : Finely porous
• Pores shape of vertical intervallar structures : Circular pores

Others informations

• Number of walls : 2
• Stratigraphical extension : Botoman
• Geographical repartition : Canada ; Europe ; Russia ; USA
• Shape of cup bulges : None
• Presence of chambers : None
• Type of habitus : Solitary ; Modular
• Structure of central Cavity (or internal if one wall) : Empty
• Presence of thorny corolla : None
• Europe : Iberia
• Russia : Altay Sayan
• Botoman : 1 ; 2
• Type of modularity : Branching by longitudinal subdivisions ; Catenulate
• Cup shapes : Cylindrical-conical
• Type of other aquiferous unit : None

Systematic

• Orders : Ajacicyathida
• Superfamillies inside the Ajacicyathina : Ethmophylloidea
• Famillies inside the Ajacicyathina : Fallocyathidae
• Shape of carcass perforations openings (OW/SW) : ?
• Cup shapes : Cylindrical-conical
• Suborders inside the Ajacicyathida : Ajacicyathina

External view

• Cup shapes : Cylindrical-conical
• Shape of cup bulges : None
• Structure of outer carcass wall (OW/SW) : Carcass wall well defined
• Type of modularity : Branching by longitudinal subdivisions ; Catenulate
• Type of habitus : Solitary ; Modular
• Presence of carcass bumps: outer wall or single wall (OW/SW) : None
• Presence of carcass external plates: outer wall or single wall (OW/SW) : None
• Presence of carcass external plates: inner carcass wall (IW) : None (external plates and/or inner wall)
• Presence of thorny corolla : None
• Type of additional sheath (OW/SW) : None
• Type of additional sheath (IW) : None
• Shape of carcass perforations openings (OW/SW) : ?
• Presence of chambers : None
• Type of other aquiferous unit : None
• Subdivision of carcass perforations openings (OW/SW) : Without subdivision ; Incipient pore subdivision
• Number of walls : 2

Transverse section

• Shape of cup bulges : None
• Structure of outer carcass wall (OW/SW) : Carcass wall well defined
• Structure of inner carcass wall (IW) : Carcass wall well defined
• Number of walls : 2
• Type of habitus : Solitary ; Modular
• Type of carcass perforations: outer wall or single wall (OW/SW) : Canals
• Presence of carcass bumps: outer wall or single wall (OW/SW) : None
• Building of carcass perforations (IW) : Without participation of vertical structures
• Type of carcass perforations: inner wall (IW) : Pores
• Structure of central Cavity (or internal if one wall) : Empty
• Type of vertical intervallar structures : Septa
• Presence of vertical intervallar structures : Present
• Presence of thorny corolla : None
• Type of links between intervallar structures : None
• Presence of intervallar cells : None
• Presence of tabulae : none
• Type of other aquiferous unit : None
• Presence of carcass external plates: outer wall or single wall (OW/SW) : None
• Presence of carcass external plates: inner carcass wall (IW) : None (external plates and/or inner wall)
• Rows number of carcass perforations per intersept (OW/SW) : More than 2 rows per intersept only
• Rows number of carcass perforations per intersept (IW) : More than 2 rows per intersept only
• Porosity of vertical intervallar structures : Aporous ; Multiperforate

Longitudinal section

• Shape of cup bulges : None
• Structure of outer carcass wall (OW/SW) : Carcass wall well defined
• Structure of inner carcass wall (IW) : Carcass wall well defined
• Number of walls : 2
• Type of modularity : Branching by longitudinal subdivisions ; Catenulate
• Type of habitus : Solitary ; Modular
• Direction of carcass canals tubes (OW/SW) : Horizontal to upwardly opening
• Origin of carcass canals (OW/SW) : Within the intervallum
• Type of carcass perforations: outer wall or single wall (OW/SW) : Canals
• Presence of carcass bumps: outer wall or single wall (OW/SW) : None
• Presence of carcass external plates: outer wall or single wall (OW/SW) : None
• Cup shapes : Cylindrical-conical
• Type of carcass perforations: inner wall (IW) : Pores
• Structure of central Cavity (or internal if one wall) : Empty
• Presence of carcass external plates: inner carcass wall (IW) : None (external plates and/or inner wall)
• Shape of morphological tubes (IW) : None
• Type of vertical intervallar structures : Septa
• Repartition of vertical intervallar structures pores : Sparsely porous
• Porosity type of vertical intervallar structures : Finely porous
• Pores shape of vertical intervallar structures : Circular pores
• Presence of vertical intervallar structures : Present
• Presence of thorny corolla : None
• Type of links between intervallar structures : None
• Presence of intervallar cells : None
• Presence of tabulae : none
• Type of other aquiferous unit : None
• Presence of chambers : None
• Shape of carcass canals tubes (OW/SW) : Curved
• Type of additional sheath (OW/SW) : None
• Type of additional sheath (IW) : None
• Presence of stipules (IW) : None
• Shape of morphological tubes (OW/SW) : Inverted-V shaped
• Rows number of carcass pores per intertabula (IW) : No tabula
• Porosity of vertical intervallar structures : Aporous ; Multiperforate

Oblique section

• Shape of cup bulges : None
• Structure of outer carcass wall (OW/SW) : Carcass wall well defined
• Structure of inner carcass wall (IW) : Carcass wall well defined
• Number of walls : 2
• Type of habitus : Solitary ; Modular
• Direction of carcass canals tubes (OW/SW) : Horizontal to upwardly opening
• Origin of carcass canals (OW/SW) : Within the intervallum
• Type of carcass perforations: outer wall or single wall (OW/SW) : Canals
• Presence of carcass bumps: outer wall or single wall (OW/SW) : None
• Presence of stipules (OW/SW) : Present
• Shape of morphological tubes (OW/SW) : Inverted-V shaped
• Rows number of carcass pores per intertabula (IW) : No tabula
• Cup shapes : Cylindrical-conical
• Building of carcass perforations (IW) : Without participation of vertical structures
• Type of carcass perforations: inner wall (IW) : Pores
• Structure of central Cavity (or internal if one wall) : Empty
• Shape of morphological tubes (IW) : None
• Type of vertical intervallar structures : Septa
• Repartition of vertical intervallar structures pores : Sparsely porous
• Porosity type of vertical intervallar structures : Finely porous
• Pores shape of vertical intervallar structures : Circular pores
• Presence of vertical intervallar structures : Present
• Presence of thorny corolla : None
• Presence of intervallar cells : None
• Presence of tabulae : none
• Presence of chambers : None
• Type of other aquiferous unit : None
• Presence of carcass external plates: outer wall or single wall (OW/SW) : None
• Presence of carcass external plates: inner carcass wall (IW) : None (external plates and/or inner wall)
• Shape of carcass canals tubes (OW/SW) : Curved
• Type of additional sheath (OW/SW) : None
• Type of additional sheath (IW) : None
• Presence of stipules (IW) : None
• Rows number of carcass perforations per intersept (OW/SW) : More than 2 rows per intersept only
• Rows number of carcass perforations per intersept (IW) : More than 2 rows per intersept only
• Shape of carcass perforations openings (IW) : Simple
• Porosity of vertical intervallar structures : Aporous ; Multiperforate
• Type of links between intervallar structures : None
• Shape of carcass perforations openings (OW/SW) : ?
• Subdivision of carcass perforations openings (OW/SW) : Without subdivision ; Incipient pore subdivision
• Subdivision of carcass perforations openings (IW) : Without subdivision

Tangential section

• Shape of carcass perforations openings (OW/SW) : ?
• Shape of carcass perforations openings (IW) : Simple
• Presence of thorny corolla : None
• Repartition of vertical intervallar structures pores : Sparsely porous
• Porosity type of vertical intervallar structures : Finely porous
• Pores shape of vertical intervallar structures : Circular pores
• Subdivision of carcass perforations openings (OW/SW) : Without subdivision ; Incipient pore subdivision
• Subdivision of carcass perforations openings (IW) : Without subdivision

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Base mise à jour le 11 mars 2014 | Page générée avec Xper2 le 11 mars 2014