Chris Mah
LightNews LightNews
banner
echinoblog.bsky.social
Chris Mah
@echinoblog.bsky.social
4.9K followers 800 following 3.1K posts
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
Posts Replies Media Videos
Pinned
echinoblog.bsky.social
Chris Mah @echinoblog.bsky.social · Nov 17
A recent account of my research in the NYT! by @megadarren.bsky.social ! #echinoday www.nytimes.com/2023/08/04/s...
New Antarctic Starfish Are Doting Parents and Vicious Predators (Published 2023)
A close examination of a collection of starfish in the Smithsonian revealed even more starfish inside those starfish.
www.nytimes.com
Reposted by Chris Mah
nudibranch.bsky.social
Our next to last #Nudivember species is Halgerda brycei

Info: www.seaslugforum.net/showall/halg...
More info: slugsite.us/bow/nudwk289...
Photos: nudipixel.net/photo/00012629
museum.wa.gov.au/online-colle...
November 29, 2025 at 6:20 PM
Reposted by Chris Mah
eruptionchaser.bsky.social
There is, or was, a place in Milford Sound, here in Aotearoa New Zealand, where you could descend steps to an underwater observation chamber, and see (amongst other things), Lingula, in its natural environment.
November 29, 2025 at 6:54 AM
Reposted by Chris Mah
elizabethbeston.bsky.social
An adorable Platyhelminthes! I see that the classification has changed, so this is now subphylum Rhabditophora? Anyhoo, a real cutie!
#marineplankton 🦑
November 28, 2025 at 8:25 PM
Reposted by Chris Mah
cambriancam.bsky.social
Welcome back to #FossilFriday

Here is a piece of limestone with beautiful Rafinesquina trentonensis brachiopods I collected from the Upper Ordovician (Katian) in Jefferson County, Missouri. These rocks are age equivalent to the upper portion of the Cincinnatian Series. Anyone like seafood?
November 28, 2025 at 6:17 PM
Reposted by Chris Mah
beetlemoses.bsky.social
November 28, 2025 at 3:26 PM
Reposted by Chris Mah
daverodland.bsky.social
Ooh, that's a lovely plectolophe!
November 28, 2025 at 2:43 PM
echinoblog.bsky.social
Crossaster papposus, a sun star munching on this brachiopod at 492 m Fjords of Alexander Archipelago, North Pacific #okeanos.. a big paleo controversy in the 90s that stars caused extinction of the brachiopods! living #fossilfriday
8 armed starfish feeding on lamp shell on vertical rock face with other lampshells in background 8 armed starfish feeding on lamp shell on vertical rock face with other lampshells in background
November 28, 2025 at 2:59 PM
Reposted by Chris Mah
echinoblog.bsky.social
BRACHIOPOD! for those have never seen a living one! here ya go, Solide Seamount, 1227 m #okeanos #saveNOAA #fossilfriday
white bivalve animal on rock but with "shells" top and bottom
April 17, 2025 at 9:30 PM
Reposted by Chris Mah
echinoblog.bsky.social
Here was an interesting mystery from 2017! #okeanos on Middle Bank, 313 m North Pacific. I think a brachiopod? but it has these weird white epizoic gelatinous things on it. Tunicate? bryozoan? benthic comb jellies? #mystery I don't think we ever quite figured it out! attn @agcollins.bsky.social
white bivalve shell with gelatinous white globs on surface
April 3, 2025 at 3:25 PM
Reposted by Chris Mah
echinoblog.bsky.social
There is always SOMEONE who has never seen a LIVING BRACHIOPOD! For for that person? Here ya go! with lophophores in view! 735 m from Giacomini Seamount in the North Pacific (Alaska) #Okeanos #fossilfriday
clam like animal with top and bottom valves and feeding swirl in the middle on rock bottom
November 27, 2024 at 4:22 PM
Reposted by Chris Mah
nhmbryozoa.bsky.social
#FossilFriday Cluster of shells of the brachiopod Platystrophia regularis from the Late Ordovician (Hirnantian) of Anticosti Island, Canada.
May 16, 2025 at 5:49 AM
Reposted by Chris Mah
historyofgeology.bsky.social
February 13, 1805, birthday of French lawyer & self-taught geologist Édouard de Verneuil. Interested in Paleozoic fossils he made important contributions to the geological surveys of the US, Russia & Europe.
The Devonian brachiopod Cyrtospirifer verneuili is named after him
February 13, 2025 at 6:31 PM
Reposted by Chris Mah
botanicalbecks.bsky.social
Today is a Fossil Friday kinda day featuring this brachiopod in a rock in the Finger Lakes region of NY :)
An external mold of a brachiopod shell in a rock. A root grows over the rock from the top left of the frame and moss covers the right of the rock.
February 21, 2025 at 9:38 PM
Reposted by Chris Mah
stardusttostarfish.bsky.social
#FossilFriday !!!

Let go of your troubles and worries and appreciate this special little fossil.

Brachiopod in a core sample, tangential cross section, the shell is unfilled, and the lophophore supports (spiralia) are recrystallized.

Middle Devonian, Keg River Formation, Alberta, Canada
February 1, 2025 at 3:33 AM
Reposted by Chris Mah
art-h-ropod.bsky.social
Coming in late for #FossilFriday with a lovely little early #Silurian (~436 MYA) spirifirid #brachiopod, Meristina obtusa. Interior view of dorsal valve showing preserved spiralia on left & partial drusy quartz cement infill. Width of valve = 24 mm. Attawapiskat Fm, #Akimiski Is, #Nunavut 🇨🇦
A view into the interior of a well-preserved brachiopod dorsal valve. The shell remained sediment-free after burial, but was secondarily coated on the inside by tiny quartz crystals. The delicate spiralled lophophore supports (spiralia) have also been "silicified" -- best seen on the left in this image. The valve is 24 mm (just under 1 inch) in width.
May 16, 2025 at 9:49 PM
Reposted by Chris Mah
bookswain.bsky.social
A plate for #FossilFriday from my copy of “A Monograph of the British Fossil Brachiopoda Vol IV, Part III, Supplement to the Permian and Carboniferous” (1890) by British palaeontologist Thomas Davidson.
Coin for scale.
A page with illustrations of fossilized brachiopod species inert fine detail. At the top in all caps it’s labeled “Carboniferous.”
October 10, 2025 at 12:03 PM
echinoblog.bsky.social
#fossilfriday
biodiversitypix.bsky.social Biodiversity Pics @biodiversitypix.bsky.social · Oct 21
🍎 Natural history of New York
Albany, D. Appleton & co. and Wiley & Putnam;1842-94.

[Source]
Illustration of various brachiopod shells from the 19th-century "Natural history of New York." The fossils, labeled with species names and features like "brachial," "pedicel," and "valve," display diverse shell shapes and textures in detailed black-and-white line drawings. The image shows 38 individual shells arranged in rows, highlighting differences in ridges, curves, and openings typical of brachiopods, marine animals with two-part shells. No apples are depicted, despite the keyword. The illustration is scientific, focusing on anatomical details for species identification and comparison. Handwritten annotations add descriptive notes around the shells.
November 28, 2025 at 2:47 PM
Reposted by Chris Mah
daverodland.bsky.social
What's up, butterflies? Is it #FossilFriday yet? ⚒️🧪

Since there was a nice piece on brachiopod encrustation earlier today, I thought we'd revisit an old classic: the D shaped strophomenid Rafinesquina, a common element of late Ordovician assemblages. Its life orientation is somewhat controversial.
Two specimens of Rafinesquina alternata from the Ordovician Richmond Group, Mt. Auburn Ohio. Shaped like a capital D with a straight hinge, the relatively flat valves are concavo-convex: they both curve in the same direction, resembling a single valve of greater thickness. These specimens are presented concave sides up. Two specimens of Rafinesquina alternata from the Ordovician Richmond Group, Mt. Auburn Ohio. Shaped like a capital D with a straight hinge, the relatively flat valves are concavo-convex: they both curve in the same direction, resembling a single valve of greater thickness. These specimens are presented concave sides down.
November 7, 2025 at 9:51 PM
Reposted by Chris Mah
nhmbryozoa.bsky.social
#FossilFriday One extra fossil from Singapore, in the black limestone cladding of the same Prada shop as the rugose coral posted earlier, a brachiopod preserving internally the calcite supports of the two arms of the lophophore visible as rings of dots on the left and right side of the fossil.
November 20, 2025 at 8:50 AM
echinoblog.bsky.social
ooo! that's a nice one from Ormestad! living #fossilfriday brachiopod lophophore www.inaturalist.org/observations...
Terebratulina retusa
Terebratulina retusa from Ormestad, Gullmarn on October 14, 2017 at 11:00 AM by Poul Erik Rasmussen
www.inaturalist.org
November 28, 2025 at 2:46 PM
echinoblog.bsky.social
FANCY French BRACHIOPOD Megathiris! SO MUCH LOPHOPHORE! living #fossilfriday www.inaturalist.org/observations...
Megathiris detruncata
Megathiris detruncata from Ouessant, France on August 16, 2020 at 04:46 PM by Sylvain Le Bris
www.inaturalist.org
November 28, 2025 at 2:44 PM
echinoblog.bsky.social
MOAR Lophophore excite! living #fossilfriday Terebratulina www.inaturalist.org/observations...
Northern Lampshell (Terebratulina septentrionalis)
Northern Lampshell from North Atlantic Ocean, Halifax, NS, CA on September 2, 2023 at 10:51 AM by Hunter Stevens
www.inaturalist.org
November 28, 2025 at 2:43 PM
echinoblog.bsky.social
Living #fossilfriday BRACHIOPOD, Terebratulina showing off its handsome lophophore! www.inaturalist.org/observations...
Northern Lampshell (Terebratulina septentrionalis)
Northern Lampshell from Beverly, MA, USA on June 11, 2023 at 01:46 PM by Alex Shure. A couple of rogue individuals in a protected overhang ≈12m depth
www.inaturalist.org
November 28, 2025 at 2:42 PM
Reposted by Chris Mah
daverodland.bsky.social
There has been some debate historically, with some workers placing them outside of crown group Gastropoda. The general form is dextrally coiled, with one surface flattened and the living chamber expanding upwards as well as outwards during growth. It had an operculum, and movement seems impractical.
Three smaller, white gastropod fossils demonstrating different perspectives on the classic logarithmic spiral, including the flattened ventral surface (the one it would lie on). Label: "Maclurites sp. Chazy limestone, Ordovician Plattsburg, New York "
November 28, 2025 at 2:09 PM
Reposted by Chris Mah
daverodland.bsky.social
When #FossilFriday is also Black Friday, one looks for black fossils ... bonus points if they were apparently purchased from a science supplier like Wards. This on is a large specimen of Maclurites, an Ordovician taxon generally believed to be sedentary, suspension feeding gastropods.
A large black gastropod fossil shaped like the classic logarithmic spiral, except that the ventral surface (the one it would lie on) is flattened and there is no sign of chambers. Label: "Maclurites sp. Chazy limestone, Ordovician Plattsburg, New York "
November 28, 2025 at 2:09 PM