3d render of Paramecium caudatum

Ceci n'est pas une (Pantoffel-)diertje.

3d render of Paramecium caudatum
#sciart

A pencil drawing of a Velociraptor sitting and looking back.

Forgot to post this yesterday for Velociraptor Awareness Day.

#dinosaur #paleoart #sciart #art

#みんなでつくるBluesky古生物図鑑
ユタカリス オリオン
Utahcaris orion
カンブリア紀 Wuliuan
アメリカ（Spence Shale）
全長約8.7cm
海産
節足動物 Arthropoda
ステム鋏角類 Stem Chelicerata
ハベリア目 Habeliida
サンクタカリス科 Sanctacarididae

This californian spider, like the other species of its Western U.S.A. genus, lives in a trapdoor burrow. This lifestyle allows it to endure the harsh conditions of its environment. Size: 2-ish max cm of body length Time period: Holocene (present day) Conservation status: Least concern/Near threatened The animal drawn is a brown spider with heaver short legs, a strong body and a raised occular region near the body front

What time is it? It’s #Cheliceratime & #spidersaturday !
And today's entry is a ground based mygalomorph spider, Aliatypus californicus!

All the basic infos are here but if you want to learn more, there’s more in the thread below!⬇️🧵

#spider #arachnid #california #sciart #bugsky #invert

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Been a pro-Superman for almost half of my life, couldn't have said better^^

Superman is one of the best characters, supporting cast, and narrative setups in comics. Love that guy. Can't wait until he's fully back in the public domain where he belongs

Illustration of Supergirl walking across a starscape, reaching out to touch a nearby falling star

Happy #Supergirl Day! :D

Spiders of the Aliatypus genus don’t spin any web and all live at ground level, where they build a vertical burrow whose walls are covered by silk threads. These spiders can sometimes cluster densely in more favorable living areas like ravines. The burrow entrance can be open or closed at will thanks to a thin, wafer-like trapdoor, a feature kinda unique among antrodiaetids since genera like Antrodiaetus rather have a disposable loose silk collar. Such trap-door, making them a bit similar to the true trap-door spiders, allows Aliatypus species to keep lower temperatures and humidity inside their burrows, making it a important feature to ensure survival in the desertic hot & dry landscapes of California. This in turn lets these spiders have an ecological niche of their own, without competition from relatives that couldn’t handle such extreme conditions.

California houses many species of the Aliatypus genus and has shaped the evolution & distribution of these spiders at least since the last Ice Age. Due to the mountainous terrains of this North American state, many animal species can end up isolated in small pockets, creating in Aliatypus case a wide patch up of many roughly similar species filling the same ecological niche in close but isolated environments A. erebus & A. janus living in several parts of California where they never encounter A. californicus. Due to the limited dispersal abilities of these abundant arthropods in California, such a situation is of great interest for studying their evolutionary history, biogeography being a major factor to take into account.

Is this drawing accurate Not that much to say, I think it encompasses pretty well what this spider looks like! Did my best on the raised ophthalmic region, not 100% satisfied but it works. The relictual tergite isn’t well defined, maybe sould have used some marker for it. The pedipalps’ base is hidden due to the walking legs position. On pictures you’ll see legs can be a bit translucent sometimes.

REFERENCES • Bradley R.A., 2012. Common Spiders of North America. University of California Press, 624 pp. · Coyle, F.A., 1974. Systematics of the Trapdoor Spider Genus Aliatypus (Araneae: Antrodiaetidae). Psyche: A Journal of Entomology 81, 431–500. · Coyle F.A., & Icenogle W.R.. 1994. Natural History of the Californian Trapdoor Spider Genus Aliatypus (Araneae, Antrodiaetidae). The Journal of Arachnology 22(3): p. 225-255. · Hedin M., Derkarabetian S., Alfaro A., Ramírez M.J. & Bond J.E., 2019. Phylogenomic analysis and revised classification of atypoid mygalomorph spiders (Araneae, Mygalomorphae), with notes on arachnid ultraconserved element loci. PeerJ 7, e6864, 24 pp. · Kulkarni S., Wood H.M. & Hormiga G., 2023. Advances in the reconstruction of the spider tree of life: A roadmap for spider systematics and comparative studies. Cladistics 39, p. 479–532. · Satler J.D., Starrett J., Hayashi C.Y. & Hedin M., 2011. Inferring Species Trees from Gene Trees in a Radiation of California Trapdoor Spiders (Araneae, Antrodiaetidae, Aliatypus). PLoS ONE 6, e25355, 13 pp. INaturalist, 2026. Aliatypus californicus. Online at https://www.inaturalist.org/taxa/491597-Aliatypus-californicus Aliatypus californicus - World Spider Catalog https://wsc.nmbe.ch/spec-data/8442

Aliatypus spiders are interesting species due to their differences with other antrodiaetids & how biogeography shaped their distribution across Western North America (and of course the usual drawing autofeedback and some refs).

Thank you for reading & I’ll see you on the next #Cheliceratime!
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Aliatypus californicus is a rather large species of folding trapdoor spider, and has a bulky body with short strong legs, leg-like pedipalps and large chelicerae. It has 8 small eyes, clustered in a small group at the prosoma’s front, and the whole ophthalmic is on an elevated spot at the body’s front. The fovea (depression at the middle of the dorsal prosomal carapace) is a pit. Rare enough for a tarantula to be mentioned, the Aliatypus genus has 3 pairs of spinnerets, while many families only have 1 or 2 pairs.

Males & females differ on several details. First, males are smaller (3,5-12 mm*) than their females counterparts (12,5-23 mm*). Sexual dimorphism is mostly visible when looking at the prosoma and chelicerae. Females have more robust chelicerae and both sexes retain a bit of external segmentation on their opisthosoma with the presence for females of 1 relictual tergite (dorsal part of a body segment among arthropods) near the opisthosoma’s front while males have 3 of them, a rare feature for a non-mesothele spider.

As its name implies, this spider is native to California, and is divided into several populations occurring across this western coastal state of the U.S.A. . One of these populations lives in the San Francisco Bay region in various forests characterised by high tree density. Like many tarantulas, this species has a longer life span than araneomorph spiders. Females can be observed all year round. Males are mostly seen during autumn when they are wandering in the open searching for a mate.

Aliatypus californicus is a species of antrodiaetid spider, a family part of the main 2 sub-groups of mygalomorphae (=tarantula broad sense), called Atypoids. These tarantulas are mostly of heavy build, with short stubby legs, and live most of the time underground in made-up burrows, like the long sock of silk spinned by purseweb spiders. Aliatypus is one of the 4 known genera of antrodiaetids, alongside Antrodiaetus, Atypoides & Hexura. The slide also comprises a phylogenetic tree showing Antrodiaetids as close relatives to Megahexura fulva rather than the more famous purseweb spiders from the atypid family

You know the drill, let's talk about its morphology, distribution & phylogeny first to meet this spider.

#Cheliceratime
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This californian spider, like the other species of its Western U.S.A. genus, lives in a trapdoor burrow. This lifestyle allows it to endure the harsh conditions of its environment. Size: 2-ish max cm of body length Time period: Holocene (present day) Conservation status: Least concern/Near threatened The animal drawn is a brown spider with heaver short legs, a strong body and a raised occular region near the body front

What time is it? It’s #Cheliceratime & #spidersaturday !
And today's entry is a ground based mygalomorph spider, Aliatypus californicus!

All the basic infos are here but if you want to learn more, there’s more in the thread below!⬇️🧵

#spider #arachnid #california #sciart #bugsky #invert

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A pic of me in cosplay as Supergirl with another cosplayer dressed as batman

A pic of me in cosplay as Supergirl blocking a sith light saber, mimicking the iconic Alex Ross's panel from the DC x Satr wars crossover in which Superman does the same thing

A pic of me in cosplay as Supergirl under a giant inflatable Spider-Man

And that's all folks, thanks again to my dear @artemisplume.bsky.social, it was one of the best days ever 💚

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A pic of me in cosplay as Supergirl shaking hands with grogu/baby yoda

A pic of me in cosplay as Supergirl with another cosplayer dressed as cat noir (miraculous)

A pic of me in cosplay as Supergirl mimicking a facing off with another cosplayer dressed as omni-man (invincible)

A pic of me in cosplay as Supergirl with another cosplayer dressed as superman

Not gonna lie, this con felt like a multiversal crossover when I look at the pics, from Star wars to Miraculous, Invicincible and other DC's folks xD

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A pic of me in cosplay as Supergirl taking off to fly in the sky

A pic of me in cosplay as Supergirl

A pic of me in cosplay as Supergirl doing the "superhero landing" pose

A pic of me in cosplay as Supergirl running

that truth, love, hope, compassion, action and kindness are the real power. And it meant everything as a closeted trans girl, it ultimately defined who I am today. Thanks to all authors who impacted so many lives like mine since 1938 by giving us this beacon of hope, long live Superman💙 ❤️ 💛

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A pic of me in cosplay as Supergirl taking off to fly in the sky

A pic of me in cosplay as supergirl with 3 Spider-Men

A pic of me in cosplay as Supergirl shaking hands with grogu/baby yoda

A pic of me in cosplay as Supergirl blocking darth vader light saber, mimicking the iconic Alex Ross's panel from the DC x Satr wars crossover in which Superman does the same things

Today's the 88th anniversary of #Superman, couldn't be a better time to post my last con pics captured by the wonderful @artemisplume.bsky.social 💚

And happy anniversary Clark. You changed everything in my life almost 13 years ago. You showed me that I was right from the start to believe...

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Pour le premier mai Sébastien Lecornu appelle a enfreindre la loi mais je suppose que si on décide de faire des blocages de commerces ouverts il y aura des sanctions ?

Un truc avec tout cette séquence médiatique qu'on vient d'avoir, c'est que c'est pas illégal de travailler le premier mai. Mais c'est illégal de faire travailler quelqu'un, c'est pour ça que les bourges veulent autant s'en débarrasser, ce jour férié il est à nous et pas à eux

Maybe just me, but my one weird feeling about arachnid is the actual mouth location was way off than what I sometime expected. The location of chelicerae are more like a big nose or horns instead of jaws (make sense since they're homologous to antennae and the name is literally pincer horns).

J'adore celle là tellement elle met l'antarctique au centre de l'océan mondial, c'est une des projections les plus représentatives de la planète je trouve

Yeah people like T. rex. People like Coldplay or U2 or Smash Mouth too.

We gotta be out there cultivating the next generation of dinosaur hipsters before this all dissolves into a boring basic hellscape of overly toothy murderbirds!

Is this paleoart accurate? I think I did a good job on this one, be aware if you search for refs most of them are still labelled as “Euproops rotundatus”. The greenish parts are a nod to the close association this species had with terrestrial environments and plants. The cardio-ophthalmic region is based on the 1996's representation of Filipiak & Krawczyński. As it’s often the case with horseshoe crabs, legs are hidden under the cephalothorax.

REFERENCES • Bicknell R.D.C. & Pates S., 2020. Pictorial Atlas of Fossil and Extant Horseshoe Crabs, With Focus on Xiphosurida. Frontiers in Earth Science 8, Article 98, 60 pp. · Foucault A., Raoult J.-F., Cecca F. & Platevoet B., 2014. Dictionnaire de Géologie, 8° edition, DUNOD, 416 pp. · Filipiak P. & Krawczyński W. 1996. Westphalian xiphosurans (Chelicerata) from the Upper Silesia Coal Basin of Sosnowiec, Poland. Acta Palaeontologica Polonica 41(4), p. 413-425. · Fisher D.C., 1979. EVIDENCE FOR SUBAERIAL ACTIVITY OF EUPROOPS DANAE (MEROSTOMATA, XIPHOSURIDA). Mazon Creek Fossils, Academic Press, p.379-447. • Lamsdell J.C., 2020. The phylogeny and systematics of Xiphosura. PeerJ 8, article e10431, 45 pp. · Lamsdell J.C. & Ocon S.B., 2025. Segmentation in early Xiphosura and the evolution of the thoracetron. Journal of Paleontology 99, p. 524–543. Colorado Plateau Geosystems Inc., 2026. Global Series. In DeepTimeMaps. Online at https://deeptimemaps.com/map-lists-thumbnails/global-series/ Dunlop J. A., Penney D. & Jekel D. 2023. A summary list of fossil spiders and their relatives. In World Spider Catalog. Natural History Museum Bern, online at http://wsc.nmbe.ch, version 23.5. The ICS international chronostratigraphic chart 2025. Episodes 2025. Online at https://stratigraphy.org/chart PaleoBiology DataBase, 2026. Prestwichianella rotundata. Online at https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=429835&is_real_user=1

And of course: the usual drawing auto-feedback & some references, thank you for reading I’ll see you on the next #Cheliceratime!

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Prestwichianella rotundata lived 318 to 314 million years ago, during the transition between the Bashkirian and Moscovian stages. At that time, the lands of the supercontinent Pangea just finished their reunion, putting what would become Europe in the Southern Hemisphere, right in the Variscan orogeny, a gigantic mountain range running at the center of Pangea. Unlike modern horseshoe crabs, P. rotundata lived in rather continental watercourses. The Carboniferous is the golden age of freshwater horseshoe crabs, as they are frequently found in past European & North American watercourses from this time.

Prestwichianella rotundata and its genus belong to the belinurines, one of the 2 suborders of xiphosurans. This large group of Paleozoic-only horseshoe crabs contains a large number of species of various sizes, all contained in one family, the belinurids. They are all characterized by having clear external segmentation on their thoracetron, prominent spiny lateral extensions of said segments, and often have wider cephalothorax and smaller eyes than limulines. The slide also comprises a phylogenetic tree showing belinurids as the sister group to limulines, both groups forming the xiphosurida order among the xiphosura group

Among belinurids, Prestwichianella rotundata counts among the most derived species, and is closely associated to a group of paedomorphic species (species with juvenile features retained to adulthood, like how us humans keep a skull shape of baby ape even when we’re adults). The question of if the genus Prestwichianella is monophyletic is still sometimes debated, as it’s often the case for many extinct horseshoe crab genera. The slide also showcases a phylogenetic tree in which the genus Prestwichianella sits next to the paedomorphic belinurids in a derived position, not close to Euproops and far from genera like Belinurus

Like modern horseshoe crabs, this species was most likely a scavenger or ate small animals. However, due to its continental environment, P. rotundata lifestyle diverged quite a bit from its modern relatives. Belinurids have long been assumed to be capable of venturing out of water like today’s marine limulids do, but given their increased proximity to terrestrial habitats, it’s often hypothesized they walked on land on a more regular basis. A significant enough number of belinurids have been discovered in sub-aerial sediments rather than aquatic ones to provide some support to this possibility. A 1979 paper also pointed to some gross similarities between P. rotundata and a trigonotarbid called Maiocercus celticus, raising the question of possible mimetism on a terrestrial chelicerate.

Belinurids like Prestwichianella rotundata are an important part of horseshoe crabs' evolution, showing how this group is far from being "living fossils" but have a complex history from which our current species aren't that much representative.

#Cheliceratime
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Prestwichianella rotundata is an extinct freshwater horseshoe crab known by numerous specimens from England, Ireland, Wales & Poland. They are found in a relatively narrow window of time of European regional stratigraphy, during the A & B subdivisions of Westphalian, a regional geological stage mainly pertinent when talking about the European Carboniferous. This species’ first mentions can be traced back to 1840, but how it has been called changed A LOT through history. It was at first called “Limulus rotundatus” in 1840, and then “Belinurus rotundus” in 1863.

This name latter stabilized more recently to “Euproops rotundatus”, and is the name you’ll find more often on the Internet. However, Euproops became time after time some sort of waste basket taxon, and was recently redefine, excluding in the process our horseshoe crab of the day. In the end, the name Prestwichianella rotundata, giving homage to Joseph Prestwich, who studied this animal first 186 years ago, was kept, and is still the one in use up to today.

Although looking a bit like today’s horseshoe crabs, P. rotundata morphology diverges from its current relative on several key points. The cephalothorax bears large noticeable spines: on the sides, the genal spines are elongated & narrow, while 2 thin & long spines extend forward from the base of the ophthalmic ridges all the way upon the thoracetron. The median region is elevated with a cardiac lobe in the shape of a large triangle, making it clearly distinct from Euproops. The eyes are small.

As it’s the norm among xiphosurans, the legs were hidden under the cephalothorax. The thoracetron is short, wide and well segmented. The axial part of these segments’ bears on some parts more or less large bumps, especially at the body end, while the segments lateral edges form spiny projections. The body ends with a sword-like telson rather short compared to horseshoe crab average.

First, let's talk a bit about its discovery, naming history and morphology, both of these topics being intertwined.

#Cheliceratime
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Previously called “Euproops rotundatus”, it was one of the many freshwater horseshoe crabs that roamed continental watercourses during the Paleozoic, and may have spent a significant amount of time on terrestrial substrates. Size : 10-15-ish cm of body length Time period : Late Carboniferous Paleoart speculativometer : Few missing details The animal drawn is a brown horseshoe crab, with a wide spiny first body part and a long sword-like ending to its body

What time is it? It’s #Cheliceratime !
A extinct freshwater horseshoe crab for this entry, Prestwichianella rotundata!

All the basic infos are here but if you want to learn more, there’s more below!⬇️🧵

#horseshoecrab #carboniferous #arthropod #paleoart #sciart #bugsky #invert
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A photo of a fossilized trilobite. It is oblong in shape, brown in color, and has a multi-segmented body.

It's Trilobite Tuesday! Trimerus is among the planet’s most widely dispersed trilobite genera. The specimen pictured here is from England’s Wren’s Nest locale. Though complete specimens of Trimerus are a rare find, fully-articulated examples measuring ~7.1 in (18 cm) in length have been uncovered.

A photo of the front cover of the comics "Superman, Up in the sky"

Been a long since I read this one, it was a blast and the final is still super emotional, made me tear up a bit

Clearly in my "this is Superman" list❤️

“Let’s be Friends!” digital oil painting now properly finished. Painted with @angrymikko.bsky.social Fast tilt (and in a few places Fast Draw) brushes. Respectfully submitted for the next edition of the #invertefest digital art book.
#art #artist #sciart #inverteart #invertebrates #illustration

If the Liberals passed this into law in 2018, Ontario students would’ve been unable to organize protests against Doug Ford’s sex-ed curriculum change

15 yr old Greta Thunberg would have been banned from posting about climate change

Teenagers actually participate in our democracy, believe it or not

This turkish eurypterid, despite its relatively generic look, is of great importance in the understanding of how these animals evolved before their Silurian golden age, both when looking at species relationships, paleobiogeography & science’s history. Size : a bit more than 10cm of body length Time period : Late Ordovician Paleoart speculativometer : Mostly based on another taxon The animal drawn looks a bit like a scorpion but without claws, short spiny legs at the front, a last pair of legs enlarged and used as fins, and a long sword-like telson in place on the sting

What time is it? It’s #Cheliceratime & #Fossilfriday!
Today, one of my favourite eurypterids for all it represents, Paraeurypterus anatoliensis!
All the basic infos are here but if you want to learn more, there’s more below!⬇️🧵

#eurypterid #ordovician #turkey #paleoart #sciart #bugsky #invert
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Donc, on perd un jour férié et le plus symbolique de tous : autant dire que tous les suivants vont tomber.
Mais c'est "librement" qu'on obéira à la consigne de l'employeur d'aller bosser, bien entendu.

The case of Paraeurypterus anatoliensis is far from being unique. Paleontology historically benefited a lot from colonialism (which used it in turn for cultural soft power), a dynamic that led to underrepresented of interest & works on non-European or non-North American fossils & people. The discoveries from Africa, South Africa, Asia & Oceania, made these last decades more & more by people from these areas unraveled ground breaking advances, like, in today’s case, for eurypterids. The entire old vision of the group, now false due to bias from historical & political choices, has led to analytical errors and ignorance of potential fossil-rich localities, and it’ll take time to recover from it & rebalance north & south knowledge.

Is this paleoart accurate ? This one is a blend of the holotype & phylogenetic bracketing, I drew it with the goal to give it a basal dolichopteroid vibe. The prosoma & mesosoma are taken straight from the original description, including for the lil’ scales on the mesosoma. Since the appendages are unknown, I chose to go with a classic Dolichopterus-like look, but still made the paddles relatively small & slender since it’s a basal species. The metasoma & telson I chose to add are of the most generic type possible for a semi-derived eurypterine, with a sword-like telson and basic segments bearing epimeres on their sides.

REFERENCES • Lamsdell J.C, 2025. Codex Eurypterida: A Revised Taxonomy Based on Concordant Parsimony and Bayesian Phylogenetic Analyses. Bulletin of the American Museum of Natural History 473, 195 pp. · Lamsdell J.C., Hoşgör I., Selden P.A., 2013. A new Ordovician eurypterid (Arthropoda: Chelicerata) from southeast Turkey: Evidence for a cryptic Ordovician record of Eurypterida. Gondwana Research 23, p. 354–366. · Monarrez P.M., Zimmt J.B., Clement A.M., Gearty W., Jacisin J.J., Jenkins K.M., Kusnerik K.M., Poust A.W., Robson S.V., Sclafani J.A., Stilson K.T., Tennakoon S.D. & Thompson C.M., 2022. Our past creates our present: a brief overview of racism and colonialism in Western paleontology. Paleobiology 48, p. 173–185. · Perinçek D., Duran O., Bozdoğan N. & Çoruh T., 1992. Stratigraphy and Paleogeographical Evolution of the Autochthonous Sedimentary Rocks in Southeast Turkey. Ozan Sungurlu Symposium, Proceedings. Tectonics and Hydrocarbon Potential of Anatolia and Surrounding Regions. Turkish Petroleum Corporation - Turkish Association of Petroleum Geologists, p. 274-305. The ICS international chronostratigraphic chart 2025. Episodes 2025. Online at https://stratigraphy.org/chart Colorado Plateau Geosystems Inc., 2026. Global Series. In DeepTimeMaps. Online at https://deeptimemaps.com/map-lists-thumbnails/global-series/ Dunlop J. A., Penney D. & Jekel D. 2023. A summary list of fossil spiders and their relatives. In World Spider Catalog. Natural History Museum Bern, online at http://wsc.nmbe.ch, version 23.5.

I wanted to talk about this species a lot also because it was one of my awakenings of how occidental dominance & colonialism affected paleontology's history, and how we're still recovering from it (+drawing feedback & refs).

Thank you for reading & I’ll see you on the next #Cheliceratime!
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