#Everglades Trip -- Consider the #HorseshoeCrab... 🙂
#HorseshoeCrabs (Limulus polyphemus) evolved some 250 million years ago and they have no close living relatives. They are true #LivingFossils and generally fascinating.
First, they are not crabs—but remotely related to spiders.
They have nine eyes, two underneath near the legs.
They have twelve legs, including specializations for pushing, feeding, and mating (males).
They breathe and excrete using book gills just behind their legs.
And here's the best part: 👉 They chew with their knees!👈
https://en.wikipedia.org/wiki/Horseshoe_crab#General_body_plan
https://richard.mdpaths.com/travel/everglades/everglades_2026/index.html
Plea to Aussie drivers as rainfall awakens 'living fossils' hiding underground https://au.news.yahoo.com/plea-to-aussie-drivers-as-rainfall-awakens-living-fossils-hiding-underground-212717684.html
Shield shrimp are widespread across inland Australia. Their eggs can remain dormant underground for years.
Everything evolves, even if it's not obvious in morphology.
#evolution #livingfossils #adaptation #morphology #genetics #immunesystems #evolutionaryhistory #evolutionarybiology
Living Fossils Revealed: The Hidden Evolution of These 4 Ancient Species | Discover Magazine https://www.discovermagazine.com/planet-earth/living-fossils-revealed-the-hidden-evolution-of-these-4-ancient-species?utm_source=pocket-newtab-en-us
Ito & Saski have taken many coevolving species of living fossils as flows over a trait space, and developed a new equation to show that living fossils are inevitable byproducts of innovation-driven taxonomic turnovers. Read now for free ahead of print!
https://www.journals.uchicago.edu/doi/10.1086/727046
#coevolving #species #livingFossils #traitSpace #taxonomicTurnovers
#NewPaper #Paleontology #Evolution #LivingFossils
Olivier Rieppel (2023)
“Living fossils” and the mosaic evolution of characters.
Frontiers in Ecology and Evolution 11: 1119418.
doi: https://doi.org/10.3389/fevo.2023.1119418
https://www.frontiersin.org/articles/10.3389/fevo.2023.1119418/full
The modern discussion of living fossils turns mostly on the persistence of archaic, or ancestral, traits in extant organisms. Prime examples mentioned by Darwin already—who also coined the term “living fossil”—include the platypus and the extant lungfishes. However, the identification of archaic traits in extant organisms requires a basis of comparison, i.e., it requires an estimate of the phylogenetic interrelationships of the living fossil in question. Phylogenetic relationships are determined not on the basis of the persistence of archaic traits, but on the basis of shared derived characters. The identification of persistent traits in an organism requires the same organism to also exhibit advanced, or specialized traits that allow its proper classification. The occurrence of such a mixture of primitive (plesiomorphic) or derived (apomorphic) traits in an organism, or species, is called the heterobathmy of characters. Willi Hennig recognized the heterobathmy of characters as quite a universal phenomenon, and made it the basis of his phylogenetic systematics.
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