5 Character optimizations

This page summarises character optimizations by showing the number of character state changes inferred at each node in a summary tree.

All character changes are mapped onto a single consensus tree. Logically coherent changes are marked in blue; logically impossible changes (which are nevertheless reconstructed by the Fitch algorithm) are marked in red. Orange denotes nodes at which homoplasy due to additional regions is mapped.

Click on a node to see the characters associated with it.

Click on the numbers by a node for details

Steps incurred at node 49:

25Body organization: Serial repetition178Sclerites: Ornament: Concentric ornament182Sclerites: Composition: Mineralogy

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 50:

96Digestive tract: Anus: Location100Sclerites: Periodically shed and replaced101Sclerites: Prominent major valves103Sclerites: Accessory sclerites: Arrangement104Sclerites: Accessory sclerites: Symmetry182Sclerites: Composition: Mineralogy187Sclerites: Composition: Microstructure: Format194Sclerites: Structure: External polygonal ornament

118Sclerites: Bivalved: Hinge line shape139Sclerites: Dorsal valve: Growth direction140Sclerites: Dorsal valve: Aspect188Sclerites: Structure: Stratiform lamellae expressed at surface189Sclerites: Structure: Stratiform laminae separated190Sclerites: Structure: Stratiform laminae with polygonal ornament

108Sclerites: Posterior valves: Serially repeated140Sclerites: Dorsal valve: Aspect159Sclerites: Ventral valve: Growth direction160Sclerites: Ventral valve: Relative size175Sclerites: Ventral valve: Umbonal perforation: Shape182Sclerites: Composition: Mineralogy190Sclerites: Structure: Stratiform laminae with polygonal ornament

Steps incurred at node 51:

10Adult setae25Body organization: Serial repetition29Body organization: Pedal groove: Foot30Body organization: Coelom31Body organization: Coelomoducts: Number34Body organization: Circulatory system55Perioral apparatus: Origin57Perioral apparatus: Musculature60Perioral apparatus: Innervation70Perioral apparatus: Tentacles: Filter system96Digestive tract: Anus: Location97Digestive tract: Anus: Migration: Within ring of tentacles99Sclerites: Present in adult (excluding setae)182Sclerites: Composition: Mineralogy186Sclerites: Composition: Microstructure: Number of distinct layers191Sclerites: Structure: Canals201Gametes: Gonocoel202Gametes: Gonad position205Gametes: Asexual reproduction206Gametes: Sexes207Gametes: Fertilization208Gametes: Egg: Size209Gametes: Egg: Protective membrane214Gametes: Spermatozoa: Anterior nuclear fossa215Gametes: Spermatozoa: Acrosome217Gametes: Spermatozoa: Acrosome: Differentiated internally220Gametes: Spermatozoa: Mid-piece221Gametes: Spermatozoa: Mid-piece: Mitochondrial location225Gametes: Spermatozoa: Mitochondria: Shape226Gametes: Spermatozoa: Mitochondria: Cristae: Configuration227Gametes: Spermatozoa: Mitochondria: Midpiece228Embryo: Micromere size230Embryo: Cleavage: Cross pattern231Embryo: Cleavage: Polar lobe formation232Embryo: Cleavage: Spiral235Larva: Apical organ: Serotonergic cells236Larva: Apical organ: Develops into adult brain238Larva: Origin of body cavity249Muscles: Dorsoventral muscles: Medioventral intercrossing250Larva: Foot251Larva: Foot: Pedal gland252Larva: Foot: Pedal gland: Retained to adulthood253Larva: Coelom: Paired258Larva: Cilia: Ciliated food groove259Larva: Cilia: Ciliary bands: Downstream264Ciliary ultrastructure: Aggregation of granules below basal plate265Ciliary ultrastructure: Basal foot: Radiating tubular fibres266Ciliary ultrastructure: Basal plate267Ciliary ultrastructure: Brush border of microvilli268Ciliary ultrastructure: Centriolar triplet derivative in basal body269Ciliary ultrastructure: Ciliary necklace with connecting strands271Ciliary ultrastructure: Compound cilia: Presence272Ciliary ultrastructure: Compound cilia: Origin274Ciliary ultrastructure: Microvilli on epidermal surface: Branched276Ciliary ultrastructure: Vertical ciliary rootlet: Shape277Ciliary ultrastructure: Secondary ciliary rootlet: Presence280Nephridia: Podocytes282Nephridia: Serve as excretory organs284Nephridia: Protonephridia286Cuticle: Layers287Cuticle: Composition288Cuticle: Fibrous layer with thick fibrils290Cuticle: Resilience291Cuticle: Microvilli293Muscles: Circular muscles300Nervous system: Glial system304Nervous system: Buccal nerve ring305Nervous system: Anterior nerve loop308Nervous system: Formation of ganglia315Nervous system: Nerve cords317Nervous system: Ventral longitudinal nerves318Nervous system: Ventral cord location333MicroRNA: mir-1989334MicroRNA: mir-1990335MicroRNA: mir-1991336MicroRNA: mir-1994

11Adult setae: Secretion12Adult setae: Secretion: Microvillar diameter13Adult setae: Secretion: Microvillar canal aspect14Adult setae: Composition: Organic constituent17Adult setae: Distribution19Adult setae: Internal constitution98Digestive tract: Anus: Migration: Position188Sclerites: Structure: Stratiform lamellae expressed at surface189Sclerites: Structure: Stratiform laminae separated190Sclerites: Structure: Stratiform laminae with polygonal ornament

13Adult setae: Secretion: Microvillar canal aspect102Sclerites: Accessory sclerites: Reduced107Sclerites: Prominent major valves: Additional valves: Nature165Sclerites: Ventral valve: Posterior surface: Extent170Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover: Extent171Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover: Identity175Sclerites: Ventral valve: Umbonal perforation: Shape178Sclerites: Ornament: Concentric ornament182Sclerites: Composition: Mineralogy186Sclerites: Composition: Microstructure: Number of distinct layers188Sclerites: Structure: Stratiform lamellae expressed at surface189Sclerites: Structure: Stratiform laminae separated190Sclerites: Structure: Stratiform laminae with polygonal ornament

Steps incurred at node 52:

12Adult setae: Secretion: Microvillar diameter16Adult setae: Composition: Mineralized core17Adult setae: Distribution26Body organization: Annulae27Body organization: Subdivided head28Body organization: Pedal groove32Body organization: Gills34Body organization: Circulatory system44Mantle cavity: Presence54Perioral apparatus: Presence71Radula84Digestive tract: Prominent pharynx88Digestive tract: Oesophageal folds89Digestive tract: Oral sphincter91Digestive tract: Paired pharyngeal diverticulae92Digestive tract: Foregut: Locomotory cilia93Digestive tract: Midgut: Subdivisions94Digestive tract: Midgut: Glands202Gametes: Gonad position203Gametes: Ovary wall saccular204Gametes: Testis wall saccular210Gametes: Egg: Site of maturation211Gametes: Spermatozoa: Nucleus: Aspect216Gametes: Spermatozoa: Acrosome: Shape218Gametes: Spermatozoa: Acrosome: Subacrosomal basal plate221Gametes: Spermatozoa: Mid-piece: Mitochondrial location224Gametes: Spermatozoa: Satellite fibre complex229Embryo: Cleavage: Equal230Embryo: Cleavage: Cross pattern239Larva: Formation of coelomoducts251Larva: Foot: Pedal gland254Larva: Coelom: Paried: Includes pericardium256Larva: Cilia: Metatroch257Larva: Cilia: Telotroch281Nephridia: Rhogocytes285Nephridia: Metanephridia287Cuticle: Composition288Cuticle: Fibrous layer with thick fibrils289Cuticle: Homogeneous layer297Muscles: Cytology298Muscles: Histology301Nervous system: Dorso-terminal sense organ303Nervous system: Nuchal organs306Nervous system: Suprarectal commissure310Nervous system: Cerebral gangila: Fused311Nervous system: Cerebral ganglia: Transverse commissures315Nervous system: Nerve cords337MicroRNA: mir-1995338MicroRNA: mir-1996339MicroRNA: mir-1997342MicroRNA: mir-2000344MicroRNA: mir-2685348MicroRNA: mir-2689350MicroRNA: mir-2691353MicroRNA: mir-2722

33Body organization: Gills: Ctenidia46Mantle cavity: Open face72Radula: Extent77Radula: Teeth: Heterodonty85Digestive tract: Buccal organ: Eversible183Sclerites: Composition: Carbonate nucleation site312Nervous system: Cerebral ganglia: Transverse commissures: Number

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 53:

1Brephic shell: Embryonic shell11Adult setae: Secretion16Adult setae: Composition: Mineralized core17Adult setae: Distribution19Adult setae: Internal constitution20Adult setae: Distinct shaft25Body organization: Serial repetition28Body organization: Pedal groove29Body organization: Pedal groove: Foot33Body organization: Gills: Ctenidia45Mantle cavity: Reduced46Mantle cavity: Open face47Mantle cavity: Sac opening71Radula72Radula: Extent73Radula: Subradular membrane74Radula: Alary processes75Radula: Bolster vesicles76Radula: Subradular organ77Radula: Teeth: Heterodonty79Radula: Teeth: More teeth per row in larger individuals80Radula: Teeth: Lateral tooth base81Radula: Teeth: Lateral tooth head82Radula: Teeth: Apatite83Radula: Teeth: Magnetite87Digestive tract: Salivary glands90Digestive tract: Oral sphincter: Reduced93Digestive tract: Midgut: Subdivisions94Digestive tract: Midgut: Glands96Digestive tract: Anus: Location99Sclerites: Present in adult (excluding setae)101Sclerites: Prominent major valves106Sclerites: Prominent major valves: Additional major valves110Sclerites: Posterior valves: Apophyses116Sclerites: Posterior valves: Differentiated intermediate shell fields139Sclerites: Dorsal valve: Growth direction140Sclerites: Dorsal valve: Aspect146Sclerites: Dorsal valve: Posterior surface: Differentiated147Sclerites: Dorsal valve: Differentiated posterior surface: Morphology178Sclerites: Ornament: Concentric ornament180Sclerites: Ornament: Radial ornament183Sclerites: Composition: Carbonate nucleation site195Sclerites: Structure: Aesthete canals200Sclerites: Structure: Articulamentum206Gametes: Sexes207Gametes: Fertilization209Gametes: Egg: Protective membrane211Gametes: Spermatozoa: Nucleus: Aspect212Gametes: Spermatozoa: Nucleus: Shape216Gametes: Spermatozoa: Acrosome: Shape217Gametes: Spermatozoa: Acrosome: Differentiated internally219Gametes: Spermatozoa: Acrosome: Subacrosomal basal plate: Basal granule221Gametes: Spermatozoa: Mid-piece: Mitochondrial location225Gametes: Spermatozoa: Mitochondria: Shape227Gametes: Spermatozoa: Mitochondria: Midpiece228Embryo: Micromere size229Embryo: Cleavage: Equal230Embryo: Cleavage: Cross pattern231Embryo: Cleavage: Polar lobe formation234Larva: Apical organ: Muscles extending to the hyposphere235Larva: Apical organ: Serotonergic cells242Larva: Enrolling muscle244Larva: Rectus muscle245Muscles: Rectus muscle246Larva: Ventrolateral muscle247Larva: Ventromedian muscle249Muscles: Dorsoventral muscles: Medioventral intercrossing251Larva: Foot: Pedal gland252Larva: Foot: Pedal gland: Retained to adulthood257Larva: Cilia: Telotroch260Larva: Cilia: Ciliary bands: Upstream266Ciliary ultrastructure: Basal plate267Ciliary ultrastructure: Brush border of microvilli273Ciliary ultrastructure: Glycocalyx ultrastructure274Ciliary ultrastructure: Microvilli on epidermal surface: Branched278Ciliary ultrastructure: Secondary ciliary rootlet: Length279Ciliary ultrastructure: Secondary ciliary rootlet: Shape292Muscles: Longitudinal muscle bands293Muscles: Circular muscles295Muscles: Exposed visceral sac with transverse musculature299Nervous system: Orthogonal302Nervous system: Statocysts304Nervous system: Buccal nerve ring306Nervous system: Suprarectal commissure307Nervous system: Suprarectal commissure: Ganglionated308Nervous system: Formation of ganglia310Nervous system: Cerebral gangila: Fused311Nervous system: Cerebral ganglia: Transverse commissures321MicroRNA: mir-36323MicroRNA: mir-124324MicroRNA: mir-190325MicroRNA: mir-219326MicroRNA: mir-242328MicroRNA: mir-1984329MicroRNA: mir-1985330MicroRNA: mir-1986332MicroRNA: mir-1988333MicroRNA: mir-1989

2Brephic shell: Morphology3Brephic shell: Embryonic shell extended in larvae4Brephic shell: Surface ornament5Brephic shell: Larval attachment structure18Adult setae: Distribution: Present on anteriormost segment47Mantle cavity: Sac opening78Radula: Teeth: Bending plane79Radula: Teeth: More teeth per row in larger individuals102Sclerites: Accessory sclerites: Reduced105Sclerites: Prominent major valves: Side slope shape107Sclerites: Prominent major valves: Additional valves: Nature108Sclerites: Posterior valves: Serially repeated109Sclerites: Posterior valves: Number116Sclerites: Posterior valves: Differentiated intermediate shell fields117Sclerites: Posterior valves: Laterally divided shell fields118Sclerites: Bivalved: Hinge line shape138Sclerites: Dorsal valve: Coiling direction139Sclerites: Dorsal valve: Growth direction140Sclerites: Dorsal valve: Aspect178Sclerites: Ornament: Concentric ornament179Sclerites: Ornament: Concentric ornament: Symmetry182Sclerites: Composition: Mineralogy186Sclerites: Composition: Microstructure: Number of distinct layers187Sclerites: Composition: Microstructure: Format196Sclerites: Structure: Aesthete canals: Orientation197Sclerites: Structure: Aesthete canals: Size variation198Sclerites: Structure: Aesthete canals: Megalaesthete bulbs312Nervous system: Cerebral ganglia: Transverse commissures: Number

47Mantle cavity: Sac opening140Sclerites: Dorsal valve: Aspect175Sclerites: Ventral valve: Umbonal perforation: Shape179Sclerites: Ornament: Concentric ornament: Symmetry187Sclerites: Composition: Microstructure: Format

Steps incurred at node 54:

2Brephic shell: Morphology10Adult setae48Mantle cavity: Pallial line138Sclerites: Dorsal valve: Coiling direction139Sclerites: Dorsal valve: Growth direction141Sclerites: Dorsal valve: Anterior projection143Sclerites: Dorsal valve: Posterior projection148Sclerites: Dorsal valve: Posterior surface: Medial groove187Sclerites: Composition: Microstructure: Format

142Sclerites: Dorsal valve: Anterior projection: Angle

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 55:

1Brephic shell: Embryonic shell2Brephic shell: Morphology25Body organization: Serial repetition33Body organization: Gills: Ctenidia46Mantle cavity: Open face48Mantle cavity: Pallial line71Radula74Radula: Alary processes75Radula: Bolster vesicles76Radula: Subradular organ78Radula: Teeth: Bending plane80Radula: Teeth: Lateral tooth base87Digestive tract: Salivary glands88Digestive tract: Oesophageal folds90Digestive tract: Oral sphincter: Reduced96Digestive tract: Anus: Location138Sclerites: Dorsal valve: Coiling direction139Sclerites: Dorsal valve: Growth direction141Sclerites: Dorsal valve: Anterior projection142Sclerites: Dorsal valve: Anterior projection: Angle143Sclerites: Dorsal valve: Posterior projection144Sclerites: Dorsal valve: Rostrum145Sclerites: Dorsal valve: Ligament146Sclerites: Dorsal valve: Posterior surface: Differentiated147Sclerites: Dorsal valve: Differentiated posterior surface: Morphology148Sclerites: Dorsal valve: Posterior surface: Medial groove178Sclerites: Ornament: Concentric ornament180Sclerites: Ornament: Radial ornament183Sclerites: Composition: Carbonate nucleation site186Sclerites: Composition: Microstructure: Number of distinct layers202Gametes: Gonad position203Gametes: Ovary wall saccular204Gametes: Testis wall saccular207Gametes: Fertilization208Gametes: Egg: Size211Gametes: Spermatozoa: Nucleus: Aspect214Gametes: Spermatozoa: Anterior nuclear fossa217Gametes: Spermatozoa: Acrosome: Differentiated internally218Gametes: Spermatozoa: Acrosome: Subacrosomal basal plate221Gametes: Spermatozoa: Mid-piece: Mitochondrial location223Gametes: Spermatozoa: Centrioles: Fusion229Embryo: Cleavage: Equal230Embryo: Cleavage: Cross pattern235Larva: Apical organ: Serotonergic cells240Larva: Retractor muscles241Larva: Velum muscle ring243Muscles: Enrolling muscle257Larva: Cilia: Telotroch267Ciliary ultrastructure: Brush border of microvilli274Ciliary ultrastructure: Microvilli on epidermal surface: Branched277Ciliary ultrastructure: Secondary ciliary rootlet: Presence283Nephridia: Serially repeated284Nephridia: Protonephridia290Cuticle: Resilience294Muscles: Hydrostatic muscular system295Muscles: Exposed visceral sac with transverse musculature296Muscles: Cephalic retractors299Nervous system: Orthogonal301Nervous system: Dorso-terminal sense organ305Nervous system: Anterior nerve loop310Nervous system: Cerebral gangila: Fused311Nervous system: Cerebral ganglia: Transverse commissures314Nervous system: Serially repeated segmental nerves316Nervous system: Nerve cords: Medulla317Nervous system: Ventral longitudinal nerves

47Mantle cavity: Sac opening179Sclerites: Ornament: Concentric ornament: Symmetry184Sclerites: Composition: Cuticle or organic matrix

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 56:

111Sclerites: Posterior valves: Jugal ridges162Sclerites: Ventral valve: Posterior surface: Differentiated

159Sclerites: Ventral valve: Growth direction160Sclerites: Ventral valve: Relative size163Sclerites: Ventral valve: Posterior surface: Growth direction

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 57:

14Adult setae: Composition: Organic constituent16Adult setae: Composition: Mineralized core112Sclerites: Posterior valves: Insertion plates116Sclerites: Posterior valves: Differentiated intermediate shell fields160Sclerites: Ventral valve: Relative size178Sclerites: Ornament: Concentric ornament197Sclerites: Structure: Aesthete canals: Size variation213Gametes: Spermatozoa: Nucleus: Nuclear filament216Gametes: Spermatozoa: Acrosome: Shape217Gametes: Spermatozoa: Acrosome: Differentiated internally219Gametes: Spermatozoa: Acrosome: Subacrosomal basal plate: Basal granule221Gametes: Spermatozoa: Mid-piece: Mitochondrial location223Gametes: Spermatozoa: Centrioles: Fusion225Gametes: Spermatozoa: Mitochondria: Shape

115Sclerites: Posterior valves: Insertion plates: Pectinate

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 58:

102Sclerites: Accessory sclerites: Reduced103Sclerites: Accessory sclerites: Arrangement104Sclerites: Accessory sclerites: Symmetry109Sclerites: Posterior valves: Number113Sclerites: Posterior valves: Insertion plates: Slit115Sclerites: Posterior valves: Insertion plates: Pectinate117Sclerites: Posterior valves: Laterally divided shell fields139Sclerites: Dorsal valve: Growth direction146Sclerites: Dorsal valve: Posterior surface: Differentiated147Sclerites: Dorsal valve: Differentiated posterior surface: Morphology162Sclerites: Ventral valve: Posterior surface: Differentiated166Sclerites: Ventral valve: Posterior surface: Delthyrium180Sclerites: Ornament: Radial ornament182Sclerites: Composition: Mineralogy198Sclerites: Structure: Aesthete canals: Megalaesthete bulbs

114Sclerites: Posterior valves: Insertion plates: Slit: Nature165Sclerites: Ventral valve: Posterior surface: Extent167Sclerites: Ventral valve: Posterior surface: Delthyrium: Shape169Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover170Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover: Extent171Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover: Identity

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 59:

20Adult setae: Distinct shaft111Sclerites: Posterior valves: Jugal ridges116Sclerites: Posterior valves: Differentiated intermediate shell fields124Sclerites: Bivalved: Apophyses139Sclerites: Dorsal valve: Growth direction147Sclerites: Dorsal valve: Differentiated posterior surface: Morphology149Sclerites: Dorsal valve: Posterior surface: Notothyrium197Sclerites: Structure: Aesthete canals: Size variation211Gametes: Spermatozoa: Nucleus: Aspect218Gametes: Spermatozoa: Acrosome: Subacrosomal basal plate

125Sclerites: Bivalved: Apophyses: Morphology150Sclerites: Dorsal valve: Posterior surface: Notothyrium: Shape151Sclerites: Dorsal valve: Posterior surface: Notothyrium: Chilidial plates

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 60:

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 61:

28Body organization: Pedal groove47Mantle cavity: Sac opening109Sclerites: Posterior valves: Number146Sclerites: Dorsal valve: Posterior surface: Differentiated147Sclerites: Dorsal valve: Differentiated posterior surface: Morphology

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 62:

9Larval setae: Paired bundles11Adult setae: Secretion14Adult setae: Composition: Organic constituent19Adult setae: Internal constitution23Adult setae: Projecting knobs31Body organization: Coelomoducts: Number34Body organization: Circulatory system62Perioral apparatus: Tentacles: Disposition69Perioral apparatus: Tentacles: Vascular system85Digestive tract: Buccal organ: Eversible96Digestive tract: Anus: Location214Gametes: Spermatozoa: Anterior nuclear fossa223Gametes: Spermatozoa: Centrioles: Fusion226Gametes: Spermatozoa: Mitochondria: Cristae: Configuration235Larva: Apical organ: Serotonergic cells238Larva: Origin of body cavity259Larva: Cilia: Ciliary bands: Downstream263Ciliary ultrastructure: Accessory centriole264Ciliary ultrastructure: Aggregation of granules below basal plate267Ciliary ultrastructure: Brush border of microvilli268Ciliary ultrastructure: Centriolar triplet derivative in basal body269Ciliary ultrastructure: Ciliary necklace with connecting strands273Ciliary ultrastructure: Glycocalyx ultrastructure274Ciliary ultrastructure: Microvilli on epidermal surface: Branched278Ciliary ultrastructure: Secondary ciliary rootlet: Length283Nephridia: Serially repeated284Nephridia: Protonephridia291Cuticle: Microvilli312Nervous system: Cerebral ganglia: Transverse commissures: Number313Nervous system: Serially repeated ganglia314Nervous system: Serially repeated segmental nerves319Nervous system: Ventral cord commissures321MicroRNA: mir-36322MicroRNA: mir-76323MicroRNA: mir-124326MicroRNA: mir-242327MicroRNA: mir-278331MicroRNA: mir-1987334MicroRNA: mir-1990335MicroRNA: mir-1991340MicroRNA: mir-1998341MicroRNA: mir-1999345MicroRNA: mir-2686346MicroRNA: mir-2687347MicroRNA: mir-2688349MicroRNA: mir-2690351MicroRNA: mir-2693352MicroRNA: mir-2693

18Adult setae: Distribution: Present on anteriormost segment98Digestive tract: Anus: Migration: Position

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 63:

18Adult setae: Distribution: Present on anteriormost segment20Adult setae: Distinct shaft21Adult setae: Hooks22Adult setae: Capitium26Body organization: Annulae27Body organization: Subdivided head32Body organization: Gills61Perioral apparatus: Tentaculate

33Body organization: Gills: Ctenidia

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 64:

15Adult setae: Composition: Enamel23Adult setae: Projecting knobs34Body organization: Circulatory system54Perioral apparatus: Presence84Digestive tract: Prominent pharynx86Digestive tract: Buccal organ: Papillae207Gametes: Fertilization208Gametes: Egg: Size211Gametes: Spermatozoa: Nucleus: Aspect216Gametes: Spermatozoa: Acrosome: Shape217Gametes: Spermatozoa: Acrosome: Differentiated internally220Gametes: Spermatozoa: Mid-piece222Gametes: Spermatozoa: Centrioles: Orientation225Gametes: Spermatozoa: Mitochondria: Shape227Gametes: Spermatozoa: Mitochondria: Midpiece256Larva: Cilia: Metatroch257Larva: Cilia: Telotroch258Larva: Cilia: Ciliated food groove312Nervous system: Cerebral ganglia: Transverse commissures: Number

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 65:

67Perioral apparatus: Tentacles: Inner nerve ring68Perioral apparatus: Tentacles: Outer nerve ring69Perioral apparatus: Tentacles: Vascular system88Digestive tract: Oesophageal folds98Digestive tract: Anus: Migration: Position210Gametes: Egg: Site of maturation211Gametes: Spermatozoa: Nucleus: Aspect214Gametes: Spermatozoa: Anterior nuclear fossa216Gametes: Spermatozoa: Acrosome: Shape222Gametes: Spermatozoa: Centrioles: Orientation223Gametes: Spermatozoa: Centrioles: Fusion229Embryo: Cleavage: Equal233Embryo: Origin of mesoderm234Larva: Apical organ: Muscles extending to the hyposphere237Larva: Brain persists into adulthood255Larva: Feeding256Larva: Cilia: Metatroch260Larva: Cilia: Ciliary bands: Upstream261Larva: Cilia: Adoral ciliary band263Ciliary ultrastructure: Accessory centriole270Ciliary ultrastructure: Monociliate epidermal cells278Ciliary ultrastructure: Secondary ciliary rootlet: Length282Nephridia: Serve as excretory organs285Nephridia: Metanephridia289Cuticle: Homogeneous layer297Muscles: Cytology299Nervous system: Orthogonal300Nervous system: Glial system308Nervous system: Formation of ganglia

184Sclerites: Composition: Cuticle or organic matrix

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 66:

1Brephic shell: Embryonic shell55Perioral apparatus: Origin56Perioral apparatus: Forms closed loop62Perioral apparatus: Tentacles: Disposition66Perioral apparatus: Tentacles: Site of addition84Digestive tract: Prominent pharynx99Sclerites: Present in adult (excluding setae)101Sclerites: Prominent major valves106Sclerites: Prominent major valves: Additional major valves129Sclerites: Bivalved: Muscle scars: Ventral 146Sclerites: Dorsal valve: Posterior surface: Differentiated147Sclerites: Dorsal valve: Differentiated posterior surface: Morphology162Sclerites: Ventral valve: Posterior surface: Differentiated184Sclerites: Composition: Cuticle or organic matrix185Sclerites: Composition: Incorporation of sedimentary particles201Gametes: Gonocoel205Gametes: Asexual reproduction206Gametes: Sexes207Gametes: Fertilization208Gametes: Egg: Size210Gametes: Egg: Site of maturation225Gametes: Spermatozoa: Mitochondria: Shape227Gametes: Spermatozoa: Mitochondria: Midpiece232Embryo: Cleavage: Spiral241Larva: Velum muscle ring258Larva: Cilia: Ciliated food groove262Larva: Cilia: Nerve ring underlying ciliated larval swimming organ267Ciliary ultrastructure: Brush border of microvilli271Ciliary ultrastructure: Compound cilia: Presence280Nephridia: Podocytes284Nephridia: Protonephridia288Cuticle: Fibrous layer with thick fibrils291Cuticle: Microvilli297Muscles: Cytology309Nervous system: Cerebral ganglia: Presence320MicroRNA: Brachiopod candidate 1354MicroRNA: mir-5045

2Brephic shell: Morphology3Brephic shell: Embryonic shell extended in larvae4Brephic shell: Surface ornament5Brephic shell: Larval attachment structure102Sclerites: Accessory sclerites: Reduced105Sclerites: Prominent major valves: Side slope shape107Sclerites: Prominent major valves: Additional valves: Nature118Sclerites: Bivalved: Hinge line shape130Sclerites: Bivalved: Muscle scars: Ventral: Position132Sclerites: Bivalved: Muscle scars: Dorsal adductors138Sclerites: Dorsal valve: Coiling direction139Sclerites: Dorsal valve: Growth direction140Sclerites: Dorsal valve: Aspect159Sclerites: Ventral valve: Growth direction160Sclerites: Ventral valve: Relative size163Sclerites: Ventral valve: Posterior surface: Growth direction165Sclerites: Ventral valve: Posterior surface: Extent178Sclerites: Ornament: Concentric ornament179Sclerites: Ornament: Concentric ornament: Symmetry182Sclerites: Composition: Mineralogy186Sclerites: Composition: Microstructure: Number of distinct layers187Sclerites: Composition: Microstructure: Format188Sclerites: Structure: Stratiform lamellae expressed at surface189Sclerites: Structure: Stratiform laminae separated190Sclerites: Structure: Stratiform laminae with polygonal ornament

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 67:

9Larval setae: Paired bundles10Adult setae15Adult setae: Composition: Enamel35Pedicle: Presence64Perioral apparatus: Tentacles: Rows per side in post-trocholophe stage98Digestive tract: Anus: Migration: Position119Sclerites: Bivalved: Enclosing filtration chamber154Sclerites: Dorsal valve: Cardinal shield155Sclerites: Dorsal valve: Cardinal processes157Sclerites: Dorsal valve: Clavicles159Sclerites: Ventral valve: Growth direction164Sclerites: Ventral valve: Posterior surface: Planar166Sclerites: Ventral valve: Posterior surface: Delthyrium179Sclerites: Ornament: Concentric ornament: Symmetry182Sclerites: Composition: Mineralogy

11Adult setae: Secretion12Adult setae: Secretion: Microvillar diameter13Adult setae: Secretion: Microvillar canal aspect14Adult setae: Composition: Organic constituent19Adult setae: Internal constitution37Pedicle: Biomineralization158Sclerites: Dorsal valve: Clavicles: Type of clavicles167Sclerites: Ventral valve: Posterior surface: Delthyrium: Shape169Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover170Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover: Extent171Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover: Identity172Sclerites: Ventral valve: Posterior surface: Delthyrium: Pseudodeltidium: Shape

122Sclerites: Bivalved: Commissure: Circular123Sclerites: Bivalved: Commissure: Lateral margins175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 68:

2Brephic shell: Morphology4Brephic shell: Surface ornament5Brephic shell: Larval attachment structure6Brephic shell: Setulose7Brephic shell: Setal sacs49Mantle canals: Presence51Mantle canals: vascula lateralia52Mantle canals: vascula media102Sclerites: Accessory sclerites: Reduced104Sclerites: Accessory sclerites: Symmetry140Sclerites: Dorsal valve: Aspect147Sclerites: Dorsal valve: Differentiated posterior surface: Morphology191Sclerites: Structure: Canals192Sclerites: Structure: Punctae

8Brephic shell: Setal sacs: Number17Adult setae: Distribution50Mantle canals: Morphology53Mantle canals: vascula terminalia

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 69:

8Brephic shell: Setal sacs: Number119Sclerites: Bivalved: Enclosing filtration chamber120Sclerites: Bivalved: Commissure: Exact correspondence of valve margins124Sclerites: Bivalved: Apophyses139Sclerites: Dorsal valve: Growth direction165Sclerites: Ventral valve: Posterior surface: Extent170Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover: Extent188Sclerites: Structure: Stratiform lamellae expressed at surface189Sclerites: Structure: Stratiform laminae separated190Sclerites: Structure: Stratiform laminae with polygonal ornament

121Sclerites: Bivalved: Commissure: Sulcate122Sclerites: Bivalved: Commissure: Circular125Sclerites: Bivalved: Apophyses: Morphology

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 70:

2Brephic shell: Morphology17Adult setae: Distribution56Perioral apparatus: Forms closed loop58Perioral apparatus: Coiling direction118Sclerites: Bivalved: Hinge line shape132Sclerites: Bivalved: Muscle scars: Dorsal adductors136Sclerites: Bivalved: Muscle scars: Dorsal diductor146Sclerites: Dorsal valve: Posterior surface: Differentiated179Sclerites: Ornament: Concentric ornament: Symmetry191Sclerites: Structure: Canals

133Sclerites: Bivalved: Muscle scars: Adductors: Position137Sclerites: Bivalved: Muscle scars: Dorsal diductor: Position

168Sclerites: Ventral valve: Posterior surface: Delthyrium: Shape: Aspect of rounded opening175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 71:

4Brephic shell: Surface ornament8Brephic shell: Setal sacs: Number23Adult setae: Projecting knobs50Mantle canals: Morphology59Perioral apparatus: Adjustor muscle62Perioral apparatus: Tentacles: Disposition65Perioral apparatus: Tentacles: Median tentacle in early development95Digestive tract: Anus: Presence98Digestive tract: Anus: Migration: Position139Sclerites: Dorsal valve: Growth direction153Sclerites: Dorsal valve: Medial septum159Sclerites: Ventral valve: Growth direction160Sclerites: Ventral valve: Relative size162Sclerites: Ventral valve: Posterior surface: Differentiated164Sclerites: Ventral valve: Posterior surface: Planar166Sclerites: Ventral valve: Posterior surface: Delthyrium167Sclerites: Ventral valve: Posterior surface: Delthyrium: Shape177Sclerites: Ventral valve: Median septum180Sclerites: Ornament: Radial ornament192Sclerites: Structure: Punctae214Gametes: Spermatozoa: Anterior nuclear fossa216Gametes: Spermatozoa: Acrosome: Shape217Gametes: Spermatozoa: Acrosome: Differentiated internally220Gametes: Spermatozoa: Mid-piece222Gametes: Spermatozoa: Centrioles: Orientation235Larva: Apical organ: Serotonergic cells256Larva: Cilia: Metatroch276Ciliary ultrastructure: Vertical ciliary rootlet: Shape278Ciliary ultrastructure: Secondary ciliary rootlet: Length289Cuticle: Homogeneous layer299Nervous system: Orthogonal

41Pedicle: Coelomic region123Sclerites: Bivalved: Commissure: Lateral margins175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 72:

1Brephic shell: Embryonic shell122Sclerites: Bivalved: Commissure: Circular127Sclerites: Bivalved: Sockets130Sclerites: Bivalved: Muscle scars: Ventral: Position147Sclerites: Dorsal valve: Differentiated posterior surface: Morphology160Sclerites: Ventral valve: Relative size172Sclerites: Ventral valve: Posterior surface: Delthyrium: Pseudodeltidium: Shape182Sclerites: Composition: Mineralogy186Sclerites: Composition: Microstructure: Number of distinct layers

123Sclerites: Bivalved: Commissure: Lateral margins

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 73:

35Pedicle: Presence38Pedicle: Bulb39Pedicle: Distal rootlets124Sclerites: Bivalved: Apophyses128Sclerites: Bivalved: Socket ridges131Sclerites: Bivalved: Muscle scars: Adjustor132Sclerites: Bivalved: Muscle scars: Dorsal adductors133Sclerites: Bivalved: Muscle scars: Adductors: Position137Sclerites: Bivalved: Muscle scars: Dorsal diductor: Position146Sclerites: Dorsal valve: Posterior surface: Differentiated155Sclerites: Dorsal valve: Cardinal processes170Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover: Extent171Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover: Identity177Sclerites: Ventral valve: Median septum178Sclerites: Ornament: Concentric ornament182Sclerites: Composition: Mineralogy187Sclerites: Composition: Microstructure: Format

36Pedicle: Constitution40Pedicle: Tapering41Pedicle: Coelomic region42Pedicle: Surface ornament125Sclerites: Bivalved: Apophyses: Morphology

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 74:

50Mantle canals: Morphology118Sclerites: Bivalved: Hinge line shape125Sclerites: Bivalved: Apophyses: Morphology126Sclerites: Bivalved: Apophyses: Dental plates147Sclerites: Dorsal valve: Differentiated posterior surface: Morphology149Sclerites: Dorsal valve: Posterior surface: Notothyrium152Sclerites: Dorsal valve: Notothyrial platform153Sclerites: Dorsal valve: Medial septum169Sclerites: Ventral valve: Posterior surface: Delthyrium: Cover180Sclerites: Ornament: Radial ornament192Sclerites: Structure: Punctae

150Sclerites: Dorsal valve: Posterior surface: Notothyrium: Shape151Sclerites: Dorsal valve: Posterior surface: Notothyrium: Chilidial plates

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 75:

1Brephic shell: Embryonic shell10Adult setae15Adult setae: Composition: Enamel35Pedicle: Presence43Pedicle: Nerve impression50Mantle canals: Morphology53Mantle canals: vascula terminalia63Perioral apparatus: Tentacles: Rows per side in trocholophe stage96Digestive tract: Anus: Location118Sclerites: Bivalved: Hinge line shape134Sclerites: Bivalved: Muscle scars: Dermal muscles135Sclerites: Bivalved: Muscle scars: Unpaired median (levator ani)136Sclerites: Bivalved: Muscle scars: Dorsal diductor140Sclerites: Dorsal valve: Aspect178Sclerites: Ornament: Concentric ornament182Sclerites: Composition: Mineralogy184Sclerites: Composition: Cuticle or organic matrix208Gametes: Egg: Size210Gametes: Egg: Site of maturation216Gametes: Spermatozoa: Acrosome: Shape235Larva: Apical organ: Serotonergic cells302Nervous system: Statocysts

36Pedicle: Constitution40Pedicle: Tapering41Pedicle: Coelomic region42Pedicle: Surface ornament

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 76:

3Brephic shell: Embryonic shell extended in larvae7Brephic shell: Setal sacs23Adult setae: Projecting knobs24Adult setae: Circling coronae38Pedicle: Bulb40Pedicle: Tapering52Mantle canals: vascula media56Perioral apparatus: Forms closed loop59Perioral apparatus: Adjustor muscle84Digestive tract: Prominent pharynx97Digestive tract: Anus: Migration: Within ring of tentacles98Digestive tract: Anus: Migration: Position122Sclerites: Bivalved: Commissure: Circular132Sclerites: Bivalved: Muscle scars: Dorsal adductors139Sclerites: Dorsal valve: Growth direction140Sclerites: Dorsal valve: Aspect146Sclerites: Dorsal valve: Posterior surface: Differentiated148Sclerites: Dorsal valve: Posterior surface: Medial groove153Sclerites: Dorsal valve: Medial septum159Sclerites: Ventral valve: Growth direction160Sclerites: Ventral valve: Relative size162Sclerites: Ventral valve: Posterior surface: Differentiated166Sclerites: Ventral valve: Posterior surface: Delthyrium177Sclerites: Ventral valve: Median septum191Sclerites: Structure: Canals192Sclerites: Structure: Punctae299Nervous system: Orthogonal

123Sclerites: Bivalved: Commissure: Lateral margins168Sclerites: Ventral valve: Posterior surface: Delthyrium: Shape: Aspect of rounded opening

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 77:

35Pedicle: Presence129Sclerites: Bivalved: Muscle scars: Ventral 153Sclerites: Dorsal valve: Medial septum159Sclerites: Ventral valve: Growth direction166Sclerites: Ventral valve: Posterior surface: Delthyrium180Sclerites: Ornament: Radial ornament

168Sclerites: Ventral valve: Posterior surface: Delthyrium: Shape: Aspect of rounded opening

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 78:

2Brephic shell: Morphology120Sclerites: Bivalved: Commissure: Exact correspondence of valve margins161Sclerites: Ventral valve: Ligula174Sclerites: Ventral valve: Umbonal perforation

121Sclerites: Bivalved: Commissure: Sulcate122Sclerites: Bivalved: Commissure: Circular123Sclerites: Bivalved: Commissure: Lateral margins

175Sclerites: Ventral valve: Umbonal perforation: Shape

Steps incurred at node 79:

106Sclerites: Prominent major valves: Additional major valves146Sclerites: Dorsal valve: Posterior surface: Differentiated147Sclerites: Dorsal valve: Differentiated posterior surface: Morphology162Sclerites: Ventral valve: Posterior surface: Differentiated164Sclerites: Ventral valve: Posterior surface: Planar

107Sclerites: Prominent major valves: Additional valves: Nature108Sclerites: Posterior valves: Serially repeated117Sclerites: Posterior valves: Laterally divided shell fields159Sclerites: Ventral valve: Growth direction160Sclerites: Ventral valve: Relative size163Sclerites: Ventral valve: Posterior surface: Growth direction165Sclerites: Ventral valve: Posterior surface: Extent

175Sclerites: Ventral valve: Umbonal perforation: Shape