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

Sekwicyathus Sekwicyathus nahanniensis HANDFIELD specimen GSC 69260 Botoman, Gataga River, British Columbia, Canada Transverse section (DEBRENNE, A. ZHURAVLEV & KRUSE, 2002)

Sekwicyathus Sekwicyathus nahanniensis HANDFIELD holotype GSC 25137 Botoman, Mackenzie Mountains, Canada Oblique longitudinal section (DEBRENNE, A. ZHURAVLEV & KRUSE, 2002)

Sekwicyathus Sekwicyathus nahanniensis HANDFIELD specimen GSC 90132 Botoman, Mackenzie Mountains, Canada Longitudinal section (DEBRENNE, A. ZHURAVLEV & KRUSE, 2002)

Outer wall

• Structure of outer carcass wall (OW/SW) : Carcass wall well defined
• Carcass perforations: outer wall or single wall (OW/SW) : Canals
• Shape of carcass canals (OW/SW) : Curved
• Direction of carcass canals (OW/SW) : Upwardly opening ; Horizontal opening
  (horizontal to upwardly opening)
• Origin of carcass canals (OW/SW) : Within the intervallum
• Relationship between carcass canals and intersept (OW/SW) : Several rows of canals per intersept
• Carcass bumps: outer wall or single wall (OW/SW) : None
• Carcass external plates: outer wall or single wall (OW/SW) : None
• Stipules : Present on outer carcass wall
• Type of morphological tubes (OW/SW) : Inverted-V shaped
• Additional sheath : None ; Present on outer wall (or single wall)
• Type of additional sheath (OW/SW) : Sieve formed by protrusions
• Repartition of bracts on additional sheath (OW/SW) : No bract on additional sheath
• Type of shieve (OW/SW) : Protrusions aren't completely connected
• Repartition of micropores (OW/SW) : Irregular

Inner wall

• Structure of inner carcass wall (IW) : Carcass wall well defined
• Stipules : Present on outer carcass wall
• Carcass perforations: inner wall (IW) : Pores
• Type of carcass pores (IW) : Simple
• Relationship between rows of carcass pores and intersept (IW) : More than 2
• Relationship between rows of carcass pores and tabulae (IW) : No tabula
• Building of carcass perforations (IW) : Without participation of vertical structures
• Carcass external plates: inner carcass wall (IW) : None (external plates and/or inner wall)
• Type of morphological tubes (IW) : None
• Additional sheath : None ; Present on outer wall (or single wall)

Intervallum

• Vertical intervallar structures : Present
• Type of vertical intervallar structures : Septa
• Repartition of vertical intervallar structures pores : Aporous ; Sparsely porous
• Porosity of vertical intervallar structures : Aporous ; Finely porous
• Pores of vertical intervallar structures : Aporous ; Circular pores
• Link between vertical intervallar structures : None
• Intervallar cells : None
• Tabulae : none

Others informations

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

Systematic

• Orders : Ajacicyathida
• Suborders inside the Ajacicyathida : Ajacicyathina
• Superfamillies inside the Ajacicyathina : Ethmophylloidea
• Famillies inside the Ajacicyathina : Fallocyathidae

External view

• Cup shapes : Cylindrical-conical
• 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
• Habitus : Solitary ; Modular
• Type of modularity : Branching by longitudinal subdivisions ; Catenulate
• Carcass bumps: outer wall or single wall (OW/SW) : None
• Carcass external plates: outer wall or single wall (OW/SW) : None
• Carcass external plates: inner carcass wall (IW) : None (external plates and/or inner wall)
• Additional sheath : None ; Present on outer wall (or single wall)
• Type of additional sheath (OW/SW) : Sieve formed by protrusions
• Repartition of bracts on additional sheath (OW/SW) : No bract on additional sheath
• Type of shieve (OW/SW) : Protrusions aren't completely connected
• Repartition of micropores (OW/SW) : Irregular
• Thorny corolla : None

Transverse section

• Shape of cup bulges : None
• Number of walls : 2
• Structure of outer carcass wall (OW/SW) : Carcass wall well defined
• Structure of inner carcass wall (IW) : Carcass wall well defined
• Habitus : Solitary ; Modular
• Central Cavity (or internal if one wall) : Empty
• Carcass perforations: outer wall or single wall (OW/SW) : Canals
• Relationship between carcass canals and intersept (OW/SW) : Several rows of canals per intersept
• Carcass bumps: outer wall or single wall (OW/SW) : None
• Carcass external plates: outer wall or single wall (OW/SW) : None
• Carcass perforations: inner wall (IW) : Pores
• Building of carcass perforations (IW) : Without participation of vertical structures
• Carcass external plates: inner carcass wall (IW) : None (external plates and/or inner wall)
• Additional sheath : None ; Present on outer wall (or single wall)
• Thorny corolla : None
• Vertical intervallar structures : Present
• Type of vertical intervallar structures : Septa
• Repartition of vertical intervallar structures pores : Aporous ; Sparsely porous
• Link between vertical intervallar structures : None
• Intervallar cells : None
• Tabulae : none
• Other aquiferous unit : None

Longitudinal section

• Shape of cup bulges : None
• Number of walls : 2
• Structure of outer carcass wall (OW/SW) : Carcass wall well defined
• Structure of inner carcass wall (IW) : Carcass wall well defined
• Habitus : Solitary ; Modular
• Type of modularity : Branching by longitudinal subdivisions ; Catenulate
• Central Cavity (or internal if one wall) : Empty
• Carcass perforations: outer wall or single wall (OW/SW) : Canals
• Shape of carcass canals (OW/SW) : Curved
• Direction of carcass canals (OW/SW) : Upwardly opening ; Horizontal opening
  (horizontal to upwardly opening)
• Origin of carcass canals (OW/SW) : Within the intervallum
• Relationship between carcass canals and intersept (OW/SW) : Several rows of canals per intersept
• Carcass bumps: outer wall or single wall (OW/SW) : None
• Carcass external plates: outer wall or single wall (OW/SW) : None
• Stipules : Present on outer carcass wall
• Type of morphological tubes (OW/SW) : Inverted-V shaped
• Carcass perforations: inner wall (IW) : Pores
• Relationship between rows of carcass pores and tabulae (IW) : No tabula
• Carcass external plates: inner carcass wall (IW) : None (external plates and/or inner wall)
• Type of morphological tubes (IW) : None
• Additional sheath : None ; Present on outer wall (or single wall)
• Type of additional sheath (OW/SW) : Sieve formed by protrusions
• Repartition of bracts on additional sheath (OW/SW) : No bract on additional sheath
• Thorny corolla : None
• Vertical intervallar structures : Present
• Type of vertical intervallar structures : Septa
• Repartition of vertical intervallar structures pores : Aporous ; Sparsely porous
• Porosity of vertical intervallar structures : Aporous ; Finely porous
• Pores of vertical intervallar structures : Aporous ; Circular pores
• Link between vertical intervallar structures : None
• Intervallar cells : None
• Tabulae : none
• Chambers : None
• Other aquiferous unit : None

Oblique section

• Shape of cup bulges : None
• Number of walls : 2
• Structure of outer carcass wall (OW/SW) : Carcass wall well defined
• Structure of inner carcass wall (IW) : Carcass wall well defined
• Habitus : Solitary ; Modular
• Central Cavity (or internal if one wall) : Empty
• Carcass perforations: outer wall or single wall (OW/SW) : Canals
• Shape of carcass canals (OW/SW) : Curved
• Direction of carcass canals (OW/SW) : Upwardly opening ; Horizontal opening
  (horizontal to upwardly opening)
• Origin of carcass canals (OW/SW) : Within the intervallum
• Relationship between carcass canals and intersept (OW/SW) : Several rows of canals per intersept
• Carcass bumps: outer wall or single wall (OW/SW) : None
• Carcass external plates: outer wall or single wall (OW/SW) : None
• Stipules : Present on outer carcass wall
• Type of morphological tubes (OW/SW) : Inverted-V shaped
• Carcass perforations: inner wall (IW) : Pores
• Relationship between rows of carcass pores and intersept (IW) : More than 2
• Relationship between rows of carcass pores and tabulae (IW) : No tabula
• Building of carcass perforations (IW) : Without participation of vertical structures
• Carcass external plates: inner carcass wall (IW) : None (external plates and/or inner wall)
• Type of morphological tubes (IW) : None
• Additional sheath : None ; Present on outer wall (or single wall)
• Type of additional sheath (OW/SW) : Sieve formed by protrusions
• Repartition of bracts on additional sheath (OW/SW) : No bract on additional sheath
• Type of shieve (OW/SW) : Protrusions aren't completely connected
• Thorny corolla : None
• Vertical intervallar structures : Present
• Type of vertical intervallar structures : Septa
• Repartition of vertical intervallar structures pores : Aporous ; Sparsely porous
• Porosity of vertical intervallar structures : Aporous ; Finely porous
• Pores of vertical intervallar structures : Aporous ; Circular pores
• Link between vertical intervallar structures : None
• Intervallar cells : None
• Tabulae : none
• Chambers : None
• Other aquiferous unit : None

Tangential section

• Type of carcass pores (IW) : Simple
• Repartition of bracts on additional sheath (OW/SW) : No bract on additional sheath
• Type of shieve (OW/SW) : Protrusions aren't completely connected
• Repartition of micropores (OW/SW) : Irregular
• Thorny corolla : None
• Repartition of vertical intervallar structures pores : Aporous ; Sparsely porous
• Porosity of vertical intervallar structures : Aporous ; Finely porous
• Pores of vertical intervallar structures : Aporous ; Circular pores