Kevin Stevens

The oldest articulated bony fish from the early Silurian period - Nature A tiny, articulated, near-complete osteichthyan from the early Silurian Chongqing Lagerstätte, represents the oldest osteichthyan occurrence including microfossils, and the earliest articulated remain...

The second reports a tiny (~3 cm) articulated fish from the early Silurian. The material is challenging, but it is unquestionably a bony fish. Fittingly named Eosteus, it co-occurs with the oldest articulated jawed fishes and cements the antiquity of osteichthyans.
www.nature.com/articles/s41...

Largest Silurian fish illuminates the origin of osteichthyan characters - Nature New findings from articulated head and trunk material of Megamastax amblyodus yield previously unseen morphological details of a Silurian stem osteichthyan.

The first revisits Megamastax, a late Silurian fish described in 2014 as a sarcopt based on isolated jaws. Remarkable new cranial material shows it is a stem osteichthyan, providing our most detailed picture of a bony fish branching before the sarcopt/actinopt split. www.nature.com/articles/s41...

Cover of the journal Nature, featuring the head of a large fish with its mouth open. A smaller fish is swimming into its mouth. The cover reads "Caught in Time: Early fossils shed light on the origins of bony fish."

Osteichthyans--the bony fishes--are by far the most diverse group of living jawed vertebrates. Two papers out today in @nature.com feature remarkable new Chinese fossils that paint a picture of substantial morphological diversity among stem osteichthyans.

As Peter Moyle wrote: "Humans are not the pinnacle of evolutionary progress but only an aberrant side branch of fish evolution."

Description of the type specimen of Cheirodopsis geikiei, a Carboniferous ray-finned fish, calling it "Imperfect fish, wanting paired and caudal fins"

Calling myself an imperfect fish from now on....

Poposaurus running simulations starting to get better than utterly ridiculous. Now just ridiculous.

New paper out from @hoehna.bsky.social Lab, led by the brilliant @bjorntko.bsky.social! We applied the Pesto software (Kopperud & Höhna, 2025) to look at lineage-specific shifts in diversification rate on large, densely-sampled phylogenies across the Tree of Life doi.org/10.1093/evle...

Snails have this really cool structure called a radula that they used to scrape hard surfaces for food. It's quite entertaining to watch 😅

Aracana - Wikipedia

Yes, male Aracana are incredibly impressive-looking.

A map shows the locations of BTO satellite tagged Cuckoos in Africa. The headshots of four Cuckoos appear in circular frames around the map, alongside the wording: First Cuckoo Update for 2026.

1/ And they’re off! 📢 Our BTO satellite-tagged Cuckoos are on the move! 🌍

Follow their migrations via our interactive map ➡️ www.bto.org/cuckoos #Ornithology 🪶

Coral City after dark stays beefin with these two French grunts mouthing off 😮😮 #frenchgrunts #grunt #mouthfight #coralcityafterdark #coralcitycamera

Short video of this pair with the male in breeding dress. 🐟 #fishkeeping

Congo Tetras can be an aggressive species, especially the males. I'll forgive them when they have this nice color.

#aquariumfish #fish #fishtanksofinstagram #aquariumlife #aquariumhobby #aquarium #animal #animalphotography #animallovers #shrimp #shrimptank

A fish swimming in front of a reef. It has large scales with an orange belly, and the green scales on its back have dark blue centres. The upper face is green with pink lines; the bottom of its head is light blue, with dark blue diagonal lines on the lower gill cover. There is a bright green patch on the tail although it's hard to see the shape as the tail is folded. #UnderwaterPhotography #WildlifePhotography #Wildlife

Wrasses can be surprisingly hard to identify. You'd think the distinctive colours would make it straightforward... but there are a LOT of them, and some are fairly similar, and their colours can vary.

This is (I think) a Linedcheek Wrasse (Oxycheilinus digramma). Pic from Anilao.

#MarineLife 🐟🌿

YouTube video by Smithsonian's National Museum of Natural History Fantastical fishes from the 1700s, Leslie Overstreet, Curator of Natural History Rare Books

While the French were establishing a settlement in New Orleans and Blackbeard was killed off the Outer Banks of NC in 1718, a printer and bookseller in Amsterdam was producing a wondrous book on Indonesian fishes of which only 16 known copies survive today. 🐠 #SciArt

Sharks as apex predators in the Late Cretaceous Western Interior Seaway empirically revealed by zinc isotope analyses Food web structures and trophic interactions among Late Cretaceous marine taxa remain largely ambiguous due to the challenges in reconstructing ecolog…

www.sciencedirect.com/science/arti...

Lead by Jeremy McCormack of @goetheuni.bsky.social, and with a miniscule contribution from me, we present geochemical evidence that sharks were marine apex predators since at least the Late Cretaceous. 🐟🦈🧪 #paleobiology #geochemistry

Round two of the striped parrotfish kiss off #stripedparrotfish #parrotfishjungle #parrotfishcapitaloftheworld #coralcitycamera #kissoff

Sharks as apex predators in the Late Cretaceous Western Interior Seaway empirically revealed by zinc isotope analyses Food web structures and trophic interactions among Late Cretaceous marine taxa remain largely ambiguous due to the challenges in reconstructing ecolog…

www.sciencedirect.com/science/arti...

Lead by Jeremy McCormack of @goetheuni.bsky.social, and with a miniscule contribution from me, we present geochemical evidence that sharks were marine apex predators since at least the Late Cretaceous. 🐟🦈🧪 #paleobiology #geochemistry

Ink sketch of some of the fish that can be let through with the Vishdeurbel. Shown are Bleak, Eel, Common roach, Perch, White bream, and Pike-perch.

Since it’s back tomorrow, #SundayFishSketch this week is some of the fish you can answer the Vishdeurbel for 🛎️🛎️ they all look very polite

This project is amazing by the way:
visdeurbel.nl/en/

Damn, first acanthomorphs in the Early Cretaceous now „chromide revival“, I just updated my cichlid origins article last year….

🐟🧪

Graphical abstract shows phylogeny of Pholidichthys

The origin of cichlids: The controversial phylogenomics of the convict fish, Pholidichthys leucotaenia

Very interesting. Will have to read in more detail later.
"... previous claims of a close evolutionary relationship between Pholidichthys and cichlids, while possible, are premature and warrant re-evaluation..."
doi.org/10.1016/j.ym...

Helsinki just went a full year without a single traffic death The capital city is Finnish’ed with car-related fatalities.

“Helsinki hasn’t registered a single traffic-related fatality in the past year…Citing data that shows the risk of pedestrian fatality is cut in half by reducing a car’s speed from 40 to 30km/hr, city officials imposed the lower limit in most of Helsinki’s residential areas and city center in 2021.”

photos from an excellent study by Cohen et al (2021) of a cerambycid beetle just straight up doing it with the flower of Disa forficaria, in a classic example of a ~sexual mimicry pollination system~

the humiliation of going on a hot date then finding out she wasn't even in the same PHYLUM (then someone writes a whole paper about it, with photos of your wiener)

A yellow cichlid with red cheeks a Blue Head and blue cheeks, Seen from the side. It has Three yellow spots in its anal fin.

Rock-dwelling cichlids like this Paralabidochromis sauvagei are known as Mbipi at the southern shore of Lake Victoria. 🐟 #photography #fishkeeping

Paramblypterus, early Permian ganoid fish

Watercolor painting of a Green Chromis, Chromis viridis. Schools of these shy damsel fish hide in acropora coral in the Indo-Pacific. The similar Caribbean fish is the Blue Chromis. This post is part of a bigger project. I’ll be painting reef fish for the next 100 days 🐠 Colors, behaviors, weirdness, and wonder included.

100 Days of Reef Fish
Iconic Fish 7/10: Green Chromis, Chromis viridis. Schools of these shy damsel fish hide in acropora coral in the Indo-Pacific. The similar Caribbean fish is the Blue Chromis.

#sciart #marinelife #coralreefs #dothe100daysproject

A chain of salps, which are mostly translucent except for the organ at the bottom (I don't know what that is). There are two orange octopuses with white tentacles on the left and lower middle of the picture. There's a blurred thing which is probably a crustacean of some kind in the middle, and a small fish to the right of that. All of the passengers are either on or inside the salps - it's hard to tell which since they're almost completely transparent. #UnderwaterPhotography #Macro #Photography #MacroPhotography #Wildlife #WildlifePhotography

Salps serve as shelter for many other critters. This is part of a much longer chain of salps; there's two octopuses, a juvenile fish and what I think is an amphipod in this photo from a blackwater dive in Balayan Bay, Anilao

🦑🐟🌿 #invertebrates

Looking forward to Utah Paleontological License Plates supporting paleo research in Utah. mail.google.com/mail/u/0/#in...
@utahpaleo-ufop.bsky.social @nhmu.bsky.social