#livingfossils — Public Fediverse posts

🔍 Why it matters: Xiphosurids (horseshoe crabs) are often called “living fossils” for their apparent #morphological #conservatism. But early forms like 𝘗𝘰𝘭𝘰𝘯𝘰𝘭𝘪𝘮𝘶𝘭𝘶𝘴 had #extreme features—hypertrophied genal spines and reduced thoracetrons—previously hypothesized as #adaptations to non-marine habitats. #LivingFossils

#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

#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

#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

#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

#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

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

#FinishedReading a fascinating look at #LivingFossils, animals and plants still with us who've maintained their biology since ancient times with few obvious changes. New Zealand features a lot of course, with e.g. #tuatara #totara #rimu #rifleman and of course the wonderfully bizarre #velvetworm of the title.