Browse Items (11 total)

Taxonomy Phylum: Mollusca Class: Cephalopoda Subclass: Ammonoidea Diagnostic features [See labelled diagram above] Aragonite shell Septa Suture (different for goniatites, ceratites and ammonites, see second diagram…

Taxonomy Phylum: Mollusca Class: Cephalopoda Subclass: Coleoidea Cohort: Belemnoidea Diagnostic Features Diagram with labelled features of belemnites 'Bullet' shape Phragmocone: chambers divided by aragonitic septa (often preserved as conical…

Taxonomy Phylum: Mollusca Class: Bivalvia Diagnostic features Palial line/palial sinus Adductor muscle scars Growth lines Dorsoventral symmetry (some exceptions, for example Gryphaea) Two hinged valves Umbo Hinge Gills (rarely…

Taxonomy Phylum: Brachiopoda Diagnostic features Two valves (brachial and pedicle) Bilateral symmetry Growth lines Adductor and ductor muscle scars Pedicle Commissure Gape Teeth and socket (articulates; no teeth or socket in…

Taxonomy Phylum: Cnidaria Class: Anthozoa Diagnostic features Radial or biradial symmetry External skeleton Septa Tabulae Stratigraphic range Ordovician to present Tabulate, rugose: Ordovician to Permian (extinct at P/T extinction) Scleractinian:…

Taxonomy Phylum: Echinodermata Class: Crinoidea Diagnostic Features Crown Stalk Pentaradial symmetry Ossicles Calyx Pinnule Holdfast Way of life Benthic (some pseudoplanktonic) Filter feeders Stratigraphic range Ordovician to present Advanced…

Taxonomy Phylum: Echinodermata Class: Echinoidea Diagnostic features Ambulacra (tube feet) Periproct (opening for anus) Peristome (opening for mouth) Pentaradial symmetry (regular echinoids) Bilateral symmetry imposed upon pentaradial symmetry…

Taxonomy Phylum: Mollusca Class: Gastropoda Diagnostic Features Coiled shell - planispiral or helical - consists of body whorl and spire Mostly aragonitic shell Shell consists of one large chamber (no septa) Aperture Siphonal notch Way of…

Taxonomy Phylum: Hemichordata Class: Graptolithina Diagnostic features Stick-shape (often branched) One or both edges may appear serrated Thecae Rhabdosome Stipes Stratigraphic range Cambrian to Carboniferous (Dendroids) Ordovician to Middle Devonian…

Taxonomy Phylum: Mollusca Class: Cephalopoda Diagnostic features Simple suture Chambers Central siphuncle Straight, curved or coiled shell Stratigraphic range Cambrian to recent Straight forms: Cambrian to Permian Coiled forms: Devonian to…