Archaeocyathan knowledge base (Cambrian)

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Rectannulus

Rectannulus DEBRENNE, 1977a

Specimen-type: Rectannulus willefertae holotype, DEBRENNE, 1977a, pl. 6, fig. 2-3

Systematics:
Order: AJACICYATHIDA R. Bedford& J. Bedford, 1939
Suborder: AJACICYATHINA R. Bedford& J. Bedford, 1939
Superfamily: BRONCHOCYATHOIDEA R. Bedford& J. Bedford, 1936
Family: DENSOCYATHIDAE Vologdin, 1937

Note:
Scales may be fused into pseudo annuli.

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Outer wall

• Shape of carcass perforations openings (OW/SW) : Simple only
• Presence of carcass external plates: outer wall or single wall (OW/SW) : None
• Size of carcass pores (OW/SW) : Uniform size
• Repartition of carcass pores (OW/SW) : Homogeneous repartition
• Type of carcass perforations: outer wall or single wall (OW/SW) : Pores
• Presence of carcass bumps: outer wall or single wall (OW/SW) : None
• Presence of stipules (OW/SW) : None
• Shape of morphological tubes (OW/SW) : None
• Structure of outer carcass wall (OW/SW) : Carcass wall well defined
• Repartition types of carcass pores (OW/SW) : Straight rows of pores
• Type of additional sheath (OW/SW) : None
• Rows number of carcass perforations per intersept (OW/SW) : 2 AND more than 2 rows per intersept
• Subdivision of carcass perforations openings (OW/SW) : Without 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) : With participation of vertical intervallar structures
• Localization of carcass annuli according tabulae (IW) : No tabula
• Presence of carcass external plates: inner carcass wall (IW) : Present
• Shape of morphological tubes (IW) : None
• Shape of carcass external plates (IW) : Arcuate ; Waved only
• Structure of inner carcass wall (IW) : Carcass wall well defined
• Type of carcass external plates (IW) : Scales ; Scales AND fused scales
• Direction of carcass external plates (IW) : Horizontal to upwardly projecting
• Type of additional sheath (IW) : None
• Presence of stipules (IW) : None
• Rows number of carcass perforations per intersept (IW) : Stirrup perforations only
• Shape of the interlocking of successive carcass annuli (IW) : Simple
• Rims of carcass external plates (IW) : Smooth
• 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 to completely 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 : Atdabanian ; Botoman
• Geographical repartition : Morocco
• 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
• Botoman : 1
• Atdabanian : 4
• 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 : Bronchocyathoidea
• Famillies inside the Ajacicyathina : Densocyathidae
• Shape of carcass perforations openings (OW/SW) : Simple only
• 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
• Size of carcass pores (OW/SW) : Uniform size
• 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
• Localization of carcass annuli according tabulae (IW) : No tabula
• Shape of carcass external plates (IW) : Arcuate ; Waved only
• Direction of carcass external plates (IW) : Horizontal to upwardly projecting
• Presence of carcass external plates: inner carcass wall (IW) : Present
• Presence of thorny corolla : None
• Type of carcass external plates (IW) : Scales ; Scales AND fused scales
• Type of additional sheath (OW/SW) : None
• Type of additional sheath (IW) : None
• Repartition of carcass pores (OW/SW) : Homogeneous repartition
• Repartition types of carcass pores (OW/SW) : Straight rows of pores
• Shape of carcass perforations openings (OW/SW) : Simple only
• Rims of carcass external plates (IW) : Smooth
• Presence of chambers : None
• Type of other aquiferous unit : None
• Subdivision of carcass perforations openings (OW/SW) : Without 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) : Pores
• Presence of carcass bumps: outer wall or single wall (OW/SW) : None
• Building of carcass perforations (IW) : With participation of vertical intervallar 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) : Present
• Rows number of carcass perforations per intersept (OW/SW) : 2 AND more than 2 rows per intersept
• Rows number of carcass perforations per intersept (IW) : Stirrup perforations only
• Rims of carcass external plates (IW) : Smooth
• Porosity of vertical intervallar structures : 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
• Type of carcass perforations: outer wall or single wall (OW/SW) : Pores
• 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
• Localization of carcass annuli according tabulae (IW) : No tabula
• Shape of carcass external plates (IW) : Arcuate ; Waved only
• Direction of carcass external plates (IW) : Horizontal to upwardly projecting
• Presence of carcass external plates: inner carcass wall (IW) : Present
• Shape of morphological tubes (IW) : None
• Type of vertical intervallar structures : Septa
• Repartition of vertical intervallar structures pores : Sparsely to completely 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
• Type of additional sheath (OW/SW) : None
• Type of additional sheath (IW) : None
• Presence of stipules (IW) : None
• Shape of the interlocking of successive carcass annuli (IW) : Simple
• Rims of carcass external plates (IW) : Smooth
• Shape of morphological tubes (OW/SW) : None
• Rows number of carcass pores per intertabula (IW) : No tabula
• Porosity of vertical intervallar structures : 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
• Size of carcass pores (OW/SW) : Uniform size
• Type of carcass perforations: outer wall or single wall (OW/SW) : Pores
• Presence of carcass bumps: outer wall or single wall (OW/SW) : None
• Presence of stipules (OW/SW) : None
• Shape of morphological tubes (OW/SW) : None
• Rows number of carcass pores per intertabula (IW) : No tabula
• Cup shapes : Cylindrical-conical
• Building of carcass perforations (IW) : With participation of vertical intervallar 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 to completely 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) : Present
• 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) : 2 AND more than 2 rows per intersept
• Rows number of carcass perforations per intersept (IW) : Stirrup perforations only
• Shape of the interlocking of successive carcass annuli (IW) : Simple
• Rims of carcass external plates (IW) : Smooth
• Shape of carcass perforations openings (IW) : Simple
• Type of carcass external plates (IW) : Scales ; Scales AND fused scales
• Shape of carcass external plates (IW) : Arcuate ; Waved only
• Direction of carcass external plates (IW) : Horizontal to upwardly projecting
• Porosity of vertical intervallar structures : Multiperforate
• Type of links between intervallar structures : None
• Shape of carcass perforations openings (OW/SW) : Simple only
• Subdivision of carcass perforations openings (OW/SW) : Without subdivision
• Subdivision of carcass perforations openings (IW) : Without subdivision

Tangential section

• Shape of carcass perforations openings (OW/SW) : Simple only
• Size of carcass pores (OW/SW) : Uniform size
• Repartition of carcass pores (OW/SW) : Homogeneous repartition
• Shape of carcass perforations openings (IW) : Simple
• Presence of thorny corolla : None
• Repartition of vertical intervallar structures pores : Sparsely to completely porous
• Porosity type of vertical intervallar structures : Finely porous
• Pores shape of vertical intervallar structures : Circular pores
• Repartition types of carcass pores (OW/SW) : Straight rows of pores
• Subdivision of carcass perforations openings (OW/SW) : Without 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