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Chris Mah

@echinoblog

The "starfish guy"(but also a little about a lot of marine invertebrates, #echinoday #echinoderms. Kaiju, comics enthusiast. Marine scientist, taxonomist, deep-sea researcher. Statements/posts made here are my own & DO NOT REPRESENT HOST organizations

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Latest posts by Chris Mah @echinoblog

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Agaricocrinus is a common Mississippian crinoid, but very beautiful. This specimen is from the Edwardsville Fm of Indiana near Crawfordsville. Each arm has delicate pinnules that would filter water for food.

#FossilFriday

06.03.2026 19:19 πŸ‘ 32 πŸ” 10 πŸ’¬ 1 πŸ“Œ 0
beige Limestone with an embedded Small Crustacean fossil (bit similar to a Shrimp) with track  marks to the right lower angle
Top left a 1€ coin for scale

beige Limestone with an embedded Small Crustacean fossil (bit similar to a Shrimp) with track marks to the right lower angle Top left a 1€ coin for scale

#Fossilfriday
long armed Crustacean with track marks, Mecochirus sp.
1€ coin for scale

Upper Jurassic (lower thitonian) Location EichstΓ€tt

From the Jura-Museum EichstΓ€tt
(Visit higly recommended)

www.jura-museum.de (in german)

06.03.2026 15:37 πŸ‘ 11 πŸ” 3 πŸ’¬ 0 πŸ“Œ 0
Two solitary rugose corals (one is only partially visible at the bottom left of the image). The scale shows that the larger specimen is around 2 cm long. The stalk by which the animals would have been attached to the substrate is in both cases pointing towards the top right.

Two solitary rugose corals (one is only partially visible at the bottom left of the image). The scale shows that the larger specimen is around 2 cm long. The stalk by which the animals would have been attached to the substrate is in both cases pointing towards the top right.

#FossilFriday

Greetings from the Paleozoic Era! These are two rugose corals from the Ordovician of Sweden, then part of the continent of Baltica!

Rugosa is an entirely extinct group of corals that disappeared during the catastrophic mass extinction at the end of the Permian.

06.03.2026 17:10 πŸ‘ 6 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
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This Ectenocrinus simplex from the Ordovician Whetstone Gulf formation of New York is pyritized or replaced with fool's gold.

#FossilFriday

06.03.2026 16:44 πŸ‘ 18 πŸ” 4 πŸ’¬ 0 πŸ“Œ 0

Seeing this post about felt nudibranchs reminded me of my daughter's assignment for freshman-level art class: a watercolor painting of an animal you'd find in Monterey Bay. She picked my favorite nudi, the Hopkins Rose. πŸ¦‘

05.03.2026 21:04 πŸ‘ 52 πŸ” 8 πŸ’¬ 7 πŸ“Œ 0

#wormwednesday

06.03.2026 16:47 πŸ‘ 4 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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This curious worm uprooted itself from the sand like a carrot being pulled up by an invisible person, and rolled around in the current for a bit before starting to dig itself back in. You can see the sand grains slowly traveling over some mucous layer as it slowly reverses into the sand.

05.03.2026 23:21 πŸ‘ 26 πŸ” 8 πŸ’¬ 0 πŸ“Œ 5
Big beauties at low tide

Big beauties at low tide

Hanging out with mollusks

Hanging out with mollusks

Meal in hand

Meal in hand

A lone star

A lone star

More seastars! The abundance of them is such a joy as they are making a great comeback on the Oregon coast!

#seastars #starfish #marinelife #tidepools #oregoncoast #photography

06.03.2026 02:17 πŸ‘ 61 πŸ” 13 πŸ’¬ 12 πŸ“Œ 0
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#FossilFriday Verbeekiella australis, among the last of the Palaeozoic β€˜horn corals’ belonging to the class Rugosa, from the Permian of Timor. The function of the unusual axial structure is unclear according to my colleague Brian Rosen.

06.03.2026 06:53 πŸ‘ 78 πŸ” 19 πŸ’¬ 3 πŸ“Œ 1
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#invertebrates

06.03.2026 10:29 πŸ‘ 188 πŸ” 39 πŸ’¬ 2 πŸ“Œ 3
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It’s the Cambrian trilobite genus Olenellus from the Kinzer formation of Lancaster County, PA. There’s a surprising amount of Cambrian goodies from that formation but it’s hard to find outcrops. #fossilfriday

06.03.2026 12:57 πŸ‘ 42 πŸ” 8 πŸ’¬ 0 πŸ“Œ 0
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Patients say measles 'worse than expected' as Utah hits 350+ infections, doctors say Health officials plead with residents to vaccinate against measles as Utah hits 358 infections.

Over 120 people have been hospitalized due to measles in Utah alone. "It is, at this time a real threat in our state and something we can do to stop it," said Dr. Leisha Nolen, state epidemiologist… pleading for people to get themselves and their children vaccinated.” @jackiantonovich.bsky.social

06.03.2026 13:18 πŸ‘ 597 πŸ” 309 πŸ’¬ 6 πŸ“Œ 105
Gary Williams: Gulf of Farallones | California Academy of Sciences
Gary Williams: Gulf of Farallones | California Academy of Sciences YouTube video by California Academy of Sciences

More of Gary Williams' video feature on his work in the Gulf of the Farallons #octocoralFriday youtu.be/8miKI_tPwXw?...

06.03.2026 16:37 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Gary Williams: Chat with an Academy Scientist | California Academy of Sciences
Gary Williams: Chat with an Academy Scientist | California Academy of Sciences YouTube video by California Academy of Sciences

More Gary Williams interviews by @calacademy.bsky.social on his softcoral research. He will be missed. #octocoralFriday youtu.be/p_jANeccyOc?...

06.03.2026 16:35 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Gary Williams: Deep Sea Corals | California Academy of Sciences
Gary Williams: Deep Sea Corals | California Academy of Sciences YouTube video by California Academy of Sciences

short video about Gary Williams research #octocoralFriday youtu.be/_GPmXh18S7Q?...

06.03.2026 16:34 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

#okeanos

06.03.2026 16:32 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
stalked colonial animal with multiple polyps extended on white sediment

stalked colonial animal with multiple polyps extended on white sediment

stalked colonial animal with multiple polyps extended on white sediment

stalked colonial animal with multiple polyps extended on white sediment

A #deepsea sea pen, Acanthoptilum from French Frigate Shoals,

06.03.2026 16:32 πŸ‘ 7 πŸ” 2 πŸ’¬ 1 πŸ“Œ 0
deep-sea soft coral animal with multiple feeding polyps on a stalk.

deep-sea soft coral animal with multiple feeding polyps on a stalk.

deep-sea soft coral animal with multiple feeding polyps on a stalk.  closeup

deep-sea soft coral animal with multiple feeding polyps on a stalk. closeup

UMBELLULA! deep-sea sea pen from 1600m Gardner Terrace in the North Pacific #octocoralFriday #okeanow

06.03.2026 16:29 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
stalked sea pen with tentacled head

stalked sea pen with tentacled head

Deep-sea pen-UBELULLA! 1514 m #okeanos #saveNOAA Valador seamount #octocoralFriday

14.04.2025 22:49 πŸ‘ 9 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0
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Umbellula lindahli Umbellula lindahli from Cascadia Basin West 1026B on September 1, 2009 at 08:16 AM by Ocean Networks Canada

Lovely Umbellula from the North Pacific! #octocoralFriday www.inaturalist.org/observations...

06.03.2026 16:24 πŸ‘ 5 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Renilla koellikeri Renilla koellikeri from San Diego County, CA, USA on January 23, 2022 at 08:16 AM by Zach Berghorst. With a striped nudibranch looking for a snack.

Sorry Renilla! this striped nudibranch is looking for a snack! #octocoralfriday www.inaturalist.org/observations...

06.03.2026 16:20 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Sea Pen (Veretillum cynomorium) Sea Pen from Troia, Setubal, Portugal on May 19, 2012 at 03:07 PM by JoΓ£o Pedro Silva

An almost picture perfect reason why sea pens are octocorals! 8 pinnate tentacles around the central mouth! #octocoralfriday www.inaturalist.org/observations...

06.03.2026 16:18 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Scytalium tentaculatum Scytalium tentaculatum from Karang Asem, Bali, Indonesia on August 17, 2015 at 12:04 PM by Mark Rosenstein

More sea pen "friends" a commensal gobie! playing the "long game" on this Scytalium #octocoralfriday www.inaturalist.org/observations...

06.03.2026 16:17 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Scytalium tentaculatum Scytalium tentaculatum from Puerto Galera, Oriental Mindoro, Philippines on May 25, 2018 at 09:09 AM by Mark Rosenstein

Sea pens are also home to numerous commensals! Such as this crab and other small critters! #octocoralFriday www.inaturalist.org/observations...

06.03.2026 16:16 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Sclerobelemnon burgeri Sclerobelemnon burgeri from Bitung, ID-SW, ID on September 15, 2019 at 08:50 AM by Jim Greenfield

oooo! Indonesian Sclerobelemnon! #octocoralFriday www.inaturalist.org/observations...

06.03.2026 16:15 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Cavernularia pusilla Cavernularia pusilla from Prom. des Anglais, Nice, France on June 6, 2020 at 11:52 PM by Julien Renoult

A very fancy (or perhaps a juvenile) Cavernularia-of course it is from France! #octocoralFriday! www.inaturalist.org/observations...

06.03.2026 16:14 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Pacific Sea Pen (Ptilosarcus undulatus) Pacific Sea Pen from Puerto Vallarta, Jal., MΓ©xico on May 1, 2021 at 11:20 AM by Sian Ka an. #bioamigos

A lovely Ptilosarcus from Mexico! #octocoralFriday www.inaturalist.org/observations...

06.03.2026 16:13 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Umbellula encrinus Umbellula encrinus on September 22, 2023 at 03:42 PM by Claude Nozères. Observed on a survey by the Greenland Institute of Natural Resources.

Somewhere in the Atlantic, this sea pen ... #octocoralFriday Umbelulla! www.inaturalist.org/observations...

06.03.2026 16:11 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Great Sea Pen (Sarcoptilus grandis) Great Sea Pen from Pt Stanvac old Jetty, Australia on February 17, 2024 at 12:57 PM by Wayne Leifert (scubawayne). I saw 3 separate sea pens on this dive

A lovely flomfy Sarcoptilus! #octocoralFriday www.inaturalist.org/observations...

06.03.2026 16:08 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Renilla koellikeri Renilla koellikeri from Cove St, Newport Beach, CA, US on December 2, 2024 at 05:31 PM by Kerckhoff Marine Laboratory. Found this washed on shore in China Cove, Ca.

oh! never seen such a festive sea pansy! and all the polyps areo out! Renilla koellikeri! #octocoralFriday www.inaturalist.org/observations...

06.03.2026 16:07 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0