Megalobrachidae

**Megalobrachidae** (lit. "big arms") is an extinct clade of megafaunal synischians.

## Taxonomy

Polypodia

Sarcopodia

Neopoda

Osteopoda

Synischia

**†Megalobrachidae**

## Immediate subtaxa

†Titanopoda

†Archemegalobrachidae

## Description

Megalobrachids were herbivorous, with the majority of species serving as browsers. Their pedipalps were equipped with hooked claws used to reach for vegetation, and they developed expanded foreguts to aid in digesting foliage, resulting in a larger cephalothorax compared to other osteopods. The Megalobrachid branch boasted the largest terrestrial animals prior to the mass extinction, with the smallest species measuring 1.5m in height and the largest at 4m.

## Evolution and Extinction

Megalobrachids first evolved around the year 4205ma, driving many large Placostracans to extinction in the process. Following the emergence of the steppe, the titanopods diverged from the main branch, although the more basal species remained in the forests.

While derived megalobrachids like the titanopods initially flourished, they quickly began to lose ground to more derived herbivores like the allobrachids. Many of the basal archemegalobrachids did not adapt for life outside forested areas, or in the case of the prenobrachids, the primeval swamps where they first evolved. Ultimately, the remaining species of megalobrachids were wiped out entirely by the mass extinction.

### Branches

* **Archemegalobrachidae**: The earliest branch, found in the forests and equatorial swamps
* **Titanopoda**: A later branch, found along the steppe

## Navigation

* **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