Orthorhachia

## Taxonomy

Polypodia

Tetrabrachia

Acanthopodia

**Orthorhachia**

Orthorhachia (lit. "straight spine") is a benthic clade of Acanthopodia, analogous to bony fish on Earth.

## Description

Orthorhachia were one of the first lineages of Acanthopods, diverging from the Hadrorhachia around 4060ma.

The first Orthorhachids were anguilliform swimmers, swimming in a matter similar to eels, lampreys and some species of knifefish. The slower yet more maneuverable form of swimming led to most pelagic Orthorhachids going extinct, having been outcompeted by the faster Hadrorhachids. However, the remaining species have flourished in Anthostome reefs, which their maneuverability is more suited for.

Modern Orthorhachids have coloration designed to help them blend into their surroundings.

### Descendants

There are two branches of the Orthorhachid tree:

* **Tanypterida:** Anguilliform swimmers
* **Remipterida:** Median-paired fin swimmers

* **Anthostoma**
	+ Archeanthostoma
	+ Gastrozoa
		- Eugastrozoa
		- Tentaclostoma
			* Lithostraca
				+ Eulithostraca
				+ Anostraca
			* Neostoma
				+ Myzostoma
					- *Pelonomus thomi*
				+ Lophostoma
					- Diplostoma
						* Placostraca
							+ Archaeoplacostraca†
							+ Euplacostraca
								- Euplacostracidae
									* Euplacostracine
									* Echinostracinae†
								- Xerostraca
						* Stenostraca
							+ Eustenostraca
								- Desmostraca
									* Archaeodesmostraca†
										+ Archedesmostracidae†
										+ Notoformes†
											- Archenotoformes†
											- Neonotoformes†
												* Thyreostraca†
												* Campylospondyli†
													+ *Erythrerpeton lequiori*†
									* Eudesmostraca
										+ Eudesmostracidae
											- Eudesmostracinae
											- Myxobolidae
										+ Dolichostraca
											- Pronocanthidae†
												* Eupronocanthidae†
												* Phylactocanthidae†
											- Eudolichostraca
												* Eudolichostracidae
												* Nothocanthidae†
							+ Coleostraca
								- Archaeocoleostraca†
								- Elastospondyli
									* Archelastospondyli
										+ Archelastospondylidae
										+ Kentrodontia
											- Eukentrodontia
												* Archekentrodontia
													+ Archekentrodontidae
													+ Neokentrodontia
														- Trypophora
														- Deinoglossidae
												* Phyllophora†
											- Aspidontia†
												* *Kremarapax mckinleyi*†
									* Opisthoptera
										+ *Eopteryx emmetti*
										+ Archeopisthoptera
											- Latoptera
												* Eulatoptera
												* Pipiodontia
													+ *Corvimimus corvusamousi*
													+ Archepipiodontia
													+ Pterolophidae
											- Picoptera
												* *Gyriphagus oelespi*
										+ Neopisthoptera†
											- Sphenoptera†
												* *Velocialatus alexani*†
											- Magnoptera†
												* Eumagnoptera†
													+ *Skotalatus rauli*†
												* Dyptopterida†
													+ *Tachynectes jocomoli*†
					- Malacoformes
						* Echinostoma
						* Eumalacoformes
							+ *unspecified*
								- Ctenognatha
									* Euctenognatha
									* Necroformes
								- *unspecified*
									* Barognatha
									* Aciculognatha
										+ Euaciculognatha
										+ Chlorodermata
							+ *unspecified*
								- *unspecified*
									* Onychognatha
									* Mastigognatha
								- Isognatha
									* Myzognatha
										+ *Vitapatatoria aspiana*
									* Euisognatha
										+ Archeisognatha
										+ Cyanodermata

* **Polypodia**
	+ Tetrabrachia
		- Tachypodia
		- Acanthopodia
			* **Orthorhachia**
				+ Tanypterida
				+ Remipterida
					- Arheremipterida
					- Synopteridae
			* Hadrorhachia
				+ Ptilopoda†
					- *Bathytitan vendari*
				+ Euhadrorhachia
					- Diplocirridae
						* Archediplocirridae
						* Astrapophora
					- Teleopterida
						* Dorypoda
							+ *Kamakivenator cosmici*
							+ Archedorypoda
							+ Xiphopoda
						* Temnopoda†
							+ *Teratodectes iasoni*
	+ Sarcopodia
		- Coelopoda
			* Eucoelopoda
			* Trichopoda
				+ *Prionorostrum aegisari*
		- Neopoda
			* Metaxypoda†
				+ *Argyroderma piacentini*
			* Osteopoda
				+ Polyschia
					- Platydontia
						* Archeplatydontia
							+ Archeplatydontidae
								- *unspecified*
									* Archeplatydontinae
										+ *Dendronomus vasquezi*
									* Xenodontia†
										+ Brachiocephalia†
										+ Euxenodontia†
											- Streptotarsi†
											- Archexenodontia†
								- Neoplatydontia
									* Pleuroptera
										+ Archepleuroptera
											- Archepleuropteridae†
												* *Anthonomos qbelocki*†
											- Platyptera
												* *Sphenorhynchus sullivanae*
												* Euplatyptera
												* Dermatopoda
													+ Archedermatopoda
													+ Neodermatopoda
														- Rhabdopoda
															* Colobathristes borchmori
														- Compsopoda
										+ Theroptera†
											- Eutheroptera†
												* *Melanopteryx alexanderi*†
											- Chlamyptera†
												* Hypsirhynchidae†
												* Archechlamyptera†
													+ Temnorhynchidae†
														- *Charcharonyx mackrethi*†
													+ Archechlamypteridae†
									* Neoplatydontidae
										+ Scandopoda
											- *Carpophagus xeni*
											- Archescandopoda
											- Neoscandopoda
												* Pholcoscelida
												* Brachyscelida
										+ Harpactopoda†
											- Euharpactopoda†
											- Tanybrachidae†
												* *Cephalocarcinus elvari*†
							+ Copetarsi†
								- *Potamodyptes andrewi*†
						* Edaphotheria
							+ Leptopoda
								- Archeleptopoda
									* Euleptopoda†
										+ Euleptopodidae†
										+ Neoleptopoda†
											- Hoplopoda†
											- Camptopoda†
												* Eucamptopoda†
												* Sphenocerata†
									* Amblypoda
								- Thylacopoda†
									* Archethylacopoda†
										+ *Pycnothrix dicksoni*†
									* Allobrachidae†
										+ Euallobrachidae†
											- Corythobrachidae†
												* Archecorythobrachidae†
												* Camarabrachidae†
													+ *Cyanolophus mcgyveri*†
											- Archeallobrachidae†
												* Archeallobrachinae†
													+ *Melanothrix oneiropolos*†
												* Ceratobrachidae†
													+ *Thyreocephalus cryarchon*†
										+ Teleobrachidae†
											- *Therizinyx elliotti†*
							+ Eurycheridae
								- Archeurycheridae†
									* Archeurycheirinae†
										+ *Prolestes solysti*†
									* *Teratocheirus*†
										+ *Teratocheuirus philipi*†
								- Lystrocheiridae
									* Lystrocheirinae
										+ *Psammonyx deschaini*
									* Trypanocheiridae
										+ Archetrypanocheiridae†
										+ Rhamphodontia
											- Eurhamphodontia
												* Archeramphodontia
													+ Apodomorpha
													+ Archeramphodontidae
														- Archeramphodontinae
														- Coryphodontia
															* Archecoryphodontia
															* Septentrioformes
																+ Phractoformes
																+ Cryptonychidae
																	- Archecryptonychidae
																	- Neocryptonychidae
																		* Theristobrachidae
																		* Glyphonychidae
																			+ Archeglyphonychidae
																			+ Archonychidae
												* Acrocheiridae
													+ Euacrocheiridae
														- Archeacrocheiridae
														- Neoacrocheiridae
															* Heterognatha
																+ Distropheognatha
																	- Archedistropheognatha
																	- Neodistropheognatha
																		* Hadronychidae
																		* Daptodontia
																			+ Dryptognatha
																			+ Flagellifera
																+ Procaecoformes
																	- Oligopoda
																	- Euprocaecoformes
																		* Euprocaecoformidae
																		* Megantroformes
															* Panhylotheria
																+ Hylotheria
																	- Thaumatotheriidae
																	- Euhylotheria
																		* Gyrinotheria
																		* Euhylotheriidae
																			+ Euhylotheriinae
																			+ Pelecodontidae
																+ Thrinaxorhynchidae
																	- Archethrinaxorhynchidae
																	- Dictyorhynchidae
													+ Apatocheiridae†
											- Oryctocheiridae
					- Dromaeopoda
						* Archedromaepoda†
							+ *Rhomaleopus*†
							+ Archedromaeopodidae†
								- *Dromovenator setnovi*†
						* Onychodontia
							+ Euonychodontia†
								- Euonychodontidae†
									* Ensidontia†
										+ Euensidontia†
										+ Prionodontia†
									* Euonychodontinae†
										+ Archeonychodontidae†
										+ Cryptodontia†
											- *Raptonyx junae*†
											- Tachydontia†
											- Eucryptodontia†
								- Hadrodontia†
							+ Allodontia
								- Euallodontia†
									* Archallodontia†
									* Eriotherinae†
								- Thecopoda
									* Euthecopoda†
										+ *Leucothrix caliburi*†
									* Amphidontia
										+ Archeamphidontia†
										+ Xenopsidae
											- *polylophodon thomasi*
											- Archexenopsidae
												* Archexenopsinae
												* Euxenopsidae
													+ Ankistrobrachidae
													+ Neoxenopsidae
														- Teleopsidae
														- Chelaphora
															* Stenochelaphora
															* Pachychelaphora
											- Stenopsidae
												* File:StenopsidaeEvo.pngArchestenopsidae
												* Neostenopsidae
													+ Peloropsidae
														- Archepeloropsidae
														- Anaxotheriidae
													+ Ceratodontia
														- Archeceratodontia
														- Neoceratodontia
															* Aratrodontia
															* Isodontia
																+ Kophodontidae
																+ Elaphrodontia
																	- Archelaphrodontia
																	- Neoelaphrodontia
																		* Spathodontia
																		* Xyrodontia
				+ Synischia
					- Megalobrachidae†
						* Archemegalobrachia†
							+ Archemegalobrachidae†
							+ Prenobrachidae†
						* Titanopoda†
							+ Procerapoda†
								- Euprocerapoda†
									* *Megaphagus matti*†
								- Stylopoda†
									* *Hybotitan bluenoti*†
							+ Baropoda†
								- Eubaropoda†
									* *Nanopus proximensis*†
									* Eubaropodidae†
								- Pachypoda†
					- Deinognatha
						* Eudeinognatha†
							+ Eudeinognathidae†
								- *Euoplos gulielmi*†
							+ Malleognatha†
						* Odontognatha
							+ Trachygnatha†
								- *Telmarchos krisi*†
							+ Dolichognatha
								- Eudolichognatha
									* Archedolichognatha†
									* Hybognatha
								- Pelagotheria†
									* Actatheria†
										+ *Eurypus geberi*†
									* Thalattotheria†
										+ Isopterygia†
										+ Anisopterygia†
											- *Pontodrakon nicholsi*†

* **Chemophyta**
	+ Archaeophyta
	+ Xenophyta
		- Caulophyta
			* Neocaulophyta
				+ Eucaulophyta
					- Eucaulophytaceae
						* Eucaulophytoideae
						* Nothodendrales†
					- Reptophyta
				+ Brachyphyta
					- Archebrachyphyta
						* Eubrachyphyta
							+ Eubrachyphytaceae
							+ Desmophyta
								- Carnophyta†
								- Chromatophyta
									* Archechromatophyta
										+ Archechromatophytacea
										+ Aphyllophyta
									* Zygophyta
										+ Zygophytacea
											- Zygodendrales
											- Archezygophytacea
										+ Harpactophyta†
						* Tylophyta
					- Cryptophyta
						* Eucryptophyta
						* Pagophyta
			* Necrophyta
		- Xylophyta
			* Euxylophyta
				+ Archexylophyta
					- Archexylophytacaea
					- Coelophyta
				+ Nodophyta
			* Altiphyta†
				+ *Trilobophyllus axidenti*†

 † = Extinct