page_title: Living fossil
section_title: Animals
hierarchical_section_title: Living fossil / Examples / Animals
caption_attribution_description: Opisthocomidae: Opisthocomus hoazin Found along the Rio Napo, Orellana, Ecuador
context_page_description: A living fossil is an extant taxon that closely resembles organisms otherwise known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossils commonly are of species-poor lineages, but they need not be.
  Living fossils exhibit stasis over geologically long time scales. Popular literature may wrongly claim that a "living fossil" has undergone no significant evolution since fossil times, with practically no molecular evolution or morphological changes. Scientific investigations have repeatedly discredited such claims.
  The minimal superficial changes to living fossils are mistakenly declared the absence of evolution, but they are examples of stabilizing selection, which is an evolutionary process—and perhaps the dominant process of morphological evolution.
context_section_description: Vertebrates
   
  Mammals
  Aardvark (Orycteropus afer)
  Amami rabbit (Pentalagus furnessi)
  Chevrotain (Tragulidae)
  Elephant shrew (Macroscelidea)
  Laotian rock rat (Laonastes aenigmamus)
  Monito del monte (Dromiciops gliroides)
  Monotremes (the platypus and echidna)
  Mountain beaver (Aplodontia rufa)
  Okapi (Okapia johnstoni)
  Opossums (Didelphidae)
  Capybara (Hydrochoerus hydrochaeris)
  Red panda (Ailurus fulgens)
  Solenodon (Solenodon cubanus and Solenodon paradoxus)
  Shrew opossum (Caenolestidae)
  Spectacled bear (Tremarctos ornatus)
  False killer whale (Pseudorca crassidens)
  Pygmy right whale (Caperea marginata)
  Birds
  Pelicans (Pelecanus) – form has been virtually unchanged since the Eocene, and is noted to have been even more conserved across the Cenozoic than that of crocodiles.
  Acanthisittidae (New Zealand "wrens") – 2 living species, a few more recently extinct. Distinct lineage of Passeriformes.
  Broad-billed sapayoa (Sapayoa aenigma) – One living species. Distinct lineage of Tyranni.
  Bearded reedling (Panurus biarmicus) – One living species. Distinct lineage of Passerida or Sylvioidea.
  Coliiformes (mousebirds) – 6 living species in 2 genera. Distinct lineage of Neoaves.
  Hoatzin (Ophisthocomus hoazin) – One living species. Distinct lineage of Neoaves.
  Magpie goose (Anseranas semipalmata) – One living species. Distinct lineage of Anseriformes.
  Seriema (Cariamidae) – 2 living species. Distinct lineage of Cariamae.
  Tinamiformes (tinamous) 50 living species. Distinct lineage of Palaeognathae.
  Reptiles
  Alligator snapping turtle (Macrochelys temminckii)
  Crocodilia (crocodiles, gavials, caimans and alligators)
  Pig-nosed turtle (Carettochelys insculpta)
  Snapping turtle (Chelydra serpentina)
  Tuatara (Sphenodon punctatus and Sphenodon guntheri)
  Amphibians
  Giant salamanders (Cryptobranchus and Andrias)
  Hula painted frog (Latonia nigriventer)
  Purple frog (Nasikabatrachus sahyadrensis)
   
  Jawless fish
  Hagfish (Myxinidae) Family
  Lamprey (Petromyzontiformes)
  Bony fish
  Arowana and arapaima (Osteoglossidae)
  Bowfin (Amia calva)
  Coelacanth (the lobed-finned Latimeria menadoensis and Latimeria chalumnae)
  Gar (Lepisosteidae)
  Queensland lungfish (Neoceratodus fosteri)
  African lungfish (Protopterus sp.)
  Sturgeons and paddlefish (Acipenseriformes)
  Bichir (family Polypteridae)
  Protanguilla palau
  Mudskipper (Oxudercinae)
  Sharks
  Blind shark (Brachaelurus waddi)
  Bullhead shark (Heterodontus sp.)
  Cow shark (sixgill sharks and relatives) (Hexanchidae)
  Elephant shark (Callorhinchus milii)
  Frilled shark (Chlamydoselachus sp.)
  Goblin shark (Mitsukurina owstoni)
  Gulper shark (Centrophorus sp.)
  Invertebrates
  Insects
  Mantophasmatodea (gladiators; a few living species)
  Meropeidae (3 living species, 4 extinct)
  Micromalthus debilis (a beetle)
  Mymarommatid wasps (10 living species in genus Palaeomymar)
  Nevrorthidae (3 species-poor genera)
  Nothomyrmecia (known as the 'dinosaur ant')
  Notiothauma reedi (a scorpionfly relative)
  Orussidae (parasitic wood wasps; about 70 living species in 16 genera)
  Peloridiidae (peloridiid bugs; fewer than 30 living species in 13 genera)
  Rhinorhipid beetles (1 living species, Triassic origin)
  Rotoitid wasps (2 living species, 14 extinct)
  Sikhotealinia zhiltzovae (a jurodid beetle)
  Syntexis libocedrii (Anaxyelidae cedar wood wasp)
  Crustaceans
  Glypheoidea (2 living species: Neoglyphea inopinata and Laurentaeglyphea neocaledonica)
  Stomatopods (mantis shrimp)
  Triops cancriformis  (also known as tadpole shrimp; a notostracan crustacean)
  Molluscs
  Nautilina (e.g., Nautilus pompilius)
  Neopilina - Monoplacophoran
  Slit snail (e.g., Entemnotrochus rumphii)
  Vampyroteuthis infernalis – the vampire squid
  Other invertebrates
  Crinoids
  Horseshoe crabs (only 4 living species of the class Xiphosura, family Limulidae)
  Lingula anatina (an inarticulate brachiopod)
  Liphistiidae (trapdoor spiders)
  Onychophorans (velvet worms)
  Valdiviathyris quenstedti (a craniforman brachiopod)
  Paleodictyon nodosum (unknown)
caption: Hoatzin are born with two visible claws on their wings, but the claws fall out once the birds reach maturity.
exif: {"Image Make": "NIKON CORPORATION", "Image Model": "NIKON D40X", "Image Orientation": "Horizontal (normal)", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Ver.1.00", "Image DateTime": "2010:10:13 08:45:05", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "216", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "300", "Thumbnail YResolution": "300", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "29344", "Thumbnail JPEGInterchangeFormatLength": "9078", "Thumbnail YCbCrPositioning": "Co-sited", "EXIF ExposureTime": "1/100", "EXIF FNumber": "8", "EXIF ExposureProgram": "Manual", "EXIF ISOSpeedRatings": "200", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2010:10:13 08:45:05", "EXIF DateTimeDigitized": "2010:10:13 08:45:05", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "4", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "24/5", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire", "EXIF FocalLength": "210", "EXIF SubSecTime": "00", "EXIF SubSecTimeOriginal": "00", "EXIF SubSecTimeDigitized": "00", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "3872", "EXIF ExifImageLength": "2592", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "29206", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CVAPattern": "[0, 2, 0, 2, 1, 2, 0, 1]", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Manual Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF FocalLengthIn35mmFilm": "315", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF SubjectDistanceRange": "0"}