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@amypteride.bsky.social Sep 23, 2026, 4:05 PM

And of course: some references, thank you for reading I’ll see you on the next #Cheliceratime!

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REFERENCES

• Bicknell R.D.C., Kimmig J., Goodman A., Turner t. & Smith P.M., 2026. New exceptionally preserved arthropod from the Furongian of Canada. BMC Biology 24 (119).

• 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.

• Caster K.E. & Brooks H.K., 1956. New fossils from the Canadian–Chazan (Ordovician) hiatus in Tennessee. Bulletins of American Paleontology 36, p. 157–199.

· Hu S., Feldmann R.M., Schweitzer C.E., Benton M.J., Huang J., Wen W., Min X., Zhang Q., Zhou C. & Ma Z., 2022. A new horseshoe crab from the Permian-Triassic transition of South China: Xiphosurids as key components of post-extinction trophic webs. Palaeogeography, Palaeoclimatology, Palaeoecology 602, 111178.

• Jocqué R. & Dippenaar-Schoeman A.S., 2007. Spider Families of the World. 2° Edition, Royal Museum of Central Africa, 336 pp.

· Krantz G.W. & Walter D.E., 2009. A Manual of Acarology. 3° Edition, Texas Tech University Press, 816 pp.

ICZN, 2026. ICZN code. Online at https://www.iczn.org/the-code/the-code-online/

@amypteride.bsky.social Sep 23, 2026, 4:05 PM

Let's dive more in the topic in these slides with 4 examples of reccuring suffixes in names of old paleozoic chelicerates, horseshoe crabs, spiders & mites

#Cheliceratime
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-aspis, the shields of the past

Lunataspis => Moon-shaped shield
Chasmataspis => Dam shield
Diploaspis => Double shield
Magnicornaspis => Shield with a noticeable horn

Several paleozoic marine chelicerates contain in their name the suffix aspis, as do in fact many paleozoic crustaceans and extinct aquatic vertebrates (especially the numerous lineages of ostracoderms & placoderms). This common root is often used due to its meaning of shield, describing quickly the sorts of hard external armors many paleozoic animals possessed, like many ancestral chelicerates had a prosoma covered by a domed shield.

-limulus, a horseshoe crab’s crest

Limulus =>Horseshoe crab
Guangyuanolimulus => Horseshoe crab from Guangyuan
Austrolimulidae => Southern horseshoe crabs

Horseshoe crabs’ diversity is mainly made up of extinct species, more than half of them having names derived from the suffix limulus (honorable mention to the Belinurus name used for several other names). This is due to the fact that the first horseshoe crab that received a scientific name was Limulus polyphemus. With time, limulus deviated from its original meaning of “oblique” to become associated with horseshoe crabs, and is now a basic choice when naming a new species, often by adding with it a geographical or morphological feature.

-thelae, a tale of spiders’ spinnerets

Mesothelae => Spinnerets on the mid-underside
Opisthothelae => Spinnerets at the body end

Spinnerets, thanks to their silk thread production & posterior position breaking the smooth outline of the opisthosoma, are an important feature to identify spiders, as it can sometimes serve to classify them. This transpired into several words ending by thelae and other derivatives, which means teat and is used in this context to describe spinnerets. Such naming had quite the impact on spiders’ classification since the main split of the order is based on this feature, the mesotheles having their spinnerets in the middle of the opisthosoma, while the opisthotheles have theirs at the end of the opisthosoma. Several tarantulas’ families also exhibit noticeable spinnerets, justifying their names to reflect this feature.

-stigmata, the breath of the mites

Endeostigmata => Internalized stigmata
Prostigmata => Stigmata usually on pushed forward
Mesostigmata => Stigmata usually on mid-body length
Astigmatina => No stigmata

Mites are some of the most diverse animals on the planet, and their classification passed through many methods depending on the decades you’re focusing on. Even tho molecular analyses are now the norm, the first classification attempts were all made on a morphological basis: this makes now several groups irrelevant in the light of today’s methods, but several really large groups, coined in reference to the relative position of the breathing openings on the body, called stigmata, are still in use due to being either valid and/or practical.

@amypteride.bsky.social Sep 23, 2026, 4:05 PM

First, a bit of context on how animals & groups are given scientific names, and why certain suffixes can stick around when it comes to give names to new species

#Cheliceratime
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Naming organisms 101

Although scientific names of organisms can seem weird sometimes (one of my personal favourites being the the wasp Aha ha), every single one of them need to have an meaning explicited in the publication first mentioning said name. Numerous rules, listed in the International Commission on Zoological Nomenclature for animals, rule how species & genera can be named in detail, while upper ranks often have greater flexibility (even tho families & sub/super ranks derived from it all have designated suffix). A species’ name is always binomial, having first the genus name, and then the species’ specific part.

Naming organisms 101

Each given name is derived from pre-existing words (traditionaly latin and greek were often used but science is becoming more and more accepting of other linguistic origins to reflect science’s plurality), often chose to depict morphology, age, locality or particular feature. It can sometimes be a derivation of another species’ scientific name (like how the dinosaur genus Parasaurolophus was at first derived from another hadrosaurid dinosaur called Saurolophus), or be an hommage to someone’s name, as in Heteropoda davidbowie. However, it often happens that some suffixes are found in numerous related species’ names.

Kokomopterus longicaudatus => “the fin of Kokomo with a long tail”

Why use similar etymological roots?

These similarities often reflect science history, as many groups were built on a species from which names of others were derived. They can also reflect past hypothesis (making scientific name an absolute treasure of knowledge in science history), like how Megarachne and Basilosaurus, both thought to be a spider and a reptile at first, are now respectively an eurypterid and a cetacean. The use of shared etymological roots is often an unsaid naming convention to give a group an identity of its own just with names. They can also be relevant to follow the methodology behind species’ identification, as numerous insects’ names are related to wing morphology and extinct mammals’ ones derived from teeth morphology.

-arachne => Arachnida
=> Arachnopulmonata
=> Douglassarachne
=> Megarachne

Why use similar etymological roots?

Another butterfly effect is to sometimes ease the comprehension of scientific names by non-biology nerds: the recurrence of certain etymological roots, especially ones similar to common names, can be a huge help to understand quicker what an animal is just by looking at its name. As a science communicator (yup I’m gonna put my own thoughts here), it can be really helpful when talking to people about extinct and/or weird species, as it gives them mental checkpoints to understand at their pace new knowledge.

-scorpio => Scorpion (common name)
=> Sardoscorpius/Gigantoscorpio/Pulmonoscorpius/Heteroscorpion (scientific names)

@amypteride.bsky.social Sep 23, 2026, 4:05 PM

What time is it? It’s #Cheliceratime!

Today a special thematic post about some chelicerates' names and why they can sometimes sound a bit similar!

All the basic infos are here but there’s more in the thread below!⬇️🧵

#arachnid #arthropod #etymology #invert #bugsky
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WHY DO SEVERAL CHELICERATES' NAMES SOUND SIMILAR?

HORSESHOE CRABS
Limulus
Guangyuanolimulus
Limulitella
Austrolimulidae
root "limulus" for "horseshoe crab"

PALEOZOIC AQUATIC CHELICERATES
Lunataspis
Chasmataspis
Diploaspis
Magnicornaspis
root "aspis" for "shield"

MITES
Endeostigmata
Prostigmata
Mesostigmata
Astigmatina
root "stigmata" for "breathing opening"

SPIDERS
Mesothelae
Opisthothelae
Hexathelidae
Macrothelidae
root "thelae" for spinneret

@amypteride.bsky.social Sep 18, 2026, 3:31 PM

Austrolimulids are a interesting case of how horseshoe crab being "living fossils" is far from their real history, showing how different they were then.

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

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Horseshoe crabs are often called living fossils, like they wouldn’t have changed since their first appearance. However, these arthropods were heavily impacted by the Great Dying. Most paleozoic groups went extinct, and in the wake of this giant mess the remaining xiphosurids underwent one of the largest evolutionnary radiation of the whole group’s history.

The Early Triassic was a strange world from our modern POV, in which horseshoe crabs could be found here and there, and would have been important predators in the fragile aquatic environments, both in fresh & salt water.

The discovery of P. zaleziankensis is the first occurrence of austrolimulids in Poland, confirming even more the extremely wide distribution of this family that went from polar regions up to northern tropics, with a presence circling all of Pangea.

This could be the signs of a post-extinction diversification that went way quicker than previously thought, in less than a million year, and/or that austrolimulids endured the Great Dying better than some of their more primitive relatives, surviving in several refuge areas from where they quickly bounced back.

Is this paleoart accurate?
It’s directly inspired from the reconstruction included in the original description, so nothing to say since it’s only a few months old.

I think I could have done better to convey depth here

It’s not really traditionnal as a color for a horseshoe crab, but heck I like to draw my austrolimulids colorful

REFERENCES

• Audycki J., Bicknell R., Niedźwiedzki G. & De Baets K., 2026. A new Triassic austrolimulid from Poland presents insight into xiphosurid evolution and palaeobiogeography at the dawn of the Mesozoic. PeerJ 14, e20950, 33 pp.

• 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.

· Feng X., Chen Z.-Q., Benton M.J., Bottjer D.J., Cribb A.T., Su L., Zhao L., Jiang Y., Zhao H., Yan P. & Huang Y., 2026. Predator-prey interactions in the Early Triassic ocean. Geological Society of America Bulletin 2026, 12 pp.

• 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/

The ICS international chronostratigraphic chart 2025. Episodes 2025. Online at https://stratigraphy.org/chart

@amypteride.bsky.social Sep 18, 2026, 3:31 PM

Let's discover this new horseshoe crab through its discovery, paleoenvironment, morphology and phylogeny, and it's worth noting it's not in the same family as modern horseshoe crabs, but it belongs to the austrolimulids, very successful extinct horseshoe crabs!

#Cheliceratime
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@amypteride.bsky.social Sep 18, 2026, 3:31 PM

What time is it? It’s #Cheliceratime & #FossilFriday!
For this entry we're talking about a recently named polish horseshoe crab!

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

#horseshoecrab #triassic #paleoart #poland #sciart #bugsky
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This species, with its super enlarged genal spines, is the oldest horseshoe crab found in Poland, and is another piece in the puzzle of how these animals were extremely successful after the Permian-Triassic mass extinction.

Size : 10-ish cm of body length
Time period : Early Triassic
Paleoart speculativometer : Few missing details

The animal drawn is a horseshoe crab but with super large and narrow elongations of its head part on its sides

@amypteride.bsky.social Sep 16, 2026, 4:04 PM

A lil' word about Hubbardia species and schizomids phylogeny and it's already time to end this post with the usual drawing autofeedback and some refs.

Thank you for reading & I’ll see you on the next #Cheliceratime!
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The genus Hubbardia contains as of now (September 2026) 9 species, all of them living only in California, making this genus endemic to Western North America. Due to being the oldest described species of the bunch, some reports of H. pentapeltis have been made outside of this area like in Florida, but are now seen as incorrect. H. pentapeltis and its relatives are ground dwellers, living in leaf litter and can withstand pretty extreme situations, some specimens having been recorded surviving 5 months without food.

Schizomids are close to vinegaroons, and they both were seen as a single order a century ago. H. pentapeltis is a basal member of the sub-family Hubbardiinae, which houses species both in the Americas and in Asia. American ones form a grade in which Hubbardia pentapeltis takes part, said grade from which emerged Asian species. Like several other arachnid orders, the phylogeny of schizomids shows a clear split between old & new world species and seems to have been heavily impacted by Pangea break up.

The slide also comprise a phylogenetic tree showing the american Hubardiidae forming a large grade from which the asian species descended.

Is this drawing accurate?
It looks a bit thin for a specimen of this species, but apart from that it looks fine to me.

The colors are a bit flat, maybe a lil’ bit of supplementary shading would have helped.

I wanted to give some movement to the drawing by raising this leg but it didn’t come out as well as I wanted.

I chose to draw a male for once, in order to highlight the modified flagellum of male schizomids

REFERENCES

· Clouse R.M., Branstetter M.G., Buenavente P., Crowley L.M., Czekanski‐Moir J., General D.E.M., Giribet G., Harvey M.S., Janies D.A., Mohagan A.B., Mohagan D.P., Sharma P.P. & Wheeler W.C., 2017. First global molecular phylogeny and biogeographical analysis of two arachnid orders (Schizomida and Uropygi) supports a tropical Pangean origin and mid‐Cretaceous diversification. Journal of Biogeography 44, p. 2660–2672.

• Cook O.F., 1899. Hubbardia, a new genus of Pedipalpi. Proceedings of the Entomological Society of Washington 4, p. 249–261.

• Dunlop J.A. & Penney D., 2012. Fossil Arachnids. Monograph Series Vol.2, Siri Scientific Press. 192 pp.

• Reddell J.R. & Cokendolpher J.C., 1995. Catalogue, bibliography, and generic revision of the order Schizomida (Arachnida). Texas Memorial Museum, Speleological Monographs 4, 170 pp.

Hubbardia pentapeltis - World Schizomid Catalog
https://wac.nmbe.ch/order/schizomida/speciesdata/5688#

@amypteride.bsky.social Sep 16, 2026, 4:04 PM

You know the drill, let's first talk about this species naming history, morphology, distribution and life cycle of this schizomid.

#Cheliceratime
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Hubbardia pentapeltis is one of the first schizomid species to have received a scientific name. It was given by Orator Fuller Cook Jr., an American entomologist, in 1899, 46 years before the name Schizomida was coined.

This species has also received other names through decades of research, having been housed sometimes under the genera Trithyreus or Schizomus. However, due to zoological naming rules, Hubbardia remained the preferred genus to name this animal.

Hubbardia pentapeltis is a 1-ish cm long arachnid, and as one of the first schizomids to have received a name, is often used as a classic template of the schizomid body plan. The animal is eyeless, with elongated antennae-like first legs, 6 walking legs and an opisthosoma ending with a short flagellum, looking almost like a miniature eyeless vinegaroon.

The similarities stop here however, the flagellum of schizomid being rather short, pedipals opening in an up-and-down move (while vinegaroons open their pedipalps to their side) and the prosoma’s carapace is divided into 3 sub-parts, all these features being observable on H. pentapeltis.

This species is also a good example of how sexual dimorphism works among schizomids, males having a kinda triangular broad, fused and enlarged flagellum (not looking so much like a flagellum in this case tho) whome females preserve a more simple flagellum.

Hubbardia pentapeltis is endemic to California, the first described specimen coming precisely from Montenery County in the Los Padres National Forest, at the South of Los Angeles.

Observations related to this species can be a bit scarced (and no particular distinction between males & females can be noted), but most of the available data highlight a decrease in activity during Northern Summer.

@amypteride.bsky.social Sep 16, 2026, 4:04 PM

What time is it? It’s #Cheliceratime !

Today's entry is about a Californian only species of schizomid!

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

#schizomid #arachnid #arthropod #sciart #bugsky #invert

This ground-based arachnid is endemic to Southern California, just like the other species of this genus. It was one of the first schizomids to receive a scientific name 127 years ago.

Size : around 10mm of body length
Time period : Holocene (Present day)
Conservation status : Least concern/Near threatened

The animal drawn is a schizomid, an eyeless arachnid walking on 6 legs and using its first legs as antennae

@amypteride.bsky.social Sep 11, 2026, 3:31 PM

What time is it? It’s #Cheliceratime & #Fossilfriday !

Today I wanted to talk about how pseudoscorpions use larger animals as taxis, and that this behavior is known from multiple fossil examples!

Thanks for watching and I'll see you in the next Cheliceratime!

#arachnid #amber #pseudoscorpion

@amypteride.bsky.social Sep 9, 2026, 4:04 PM

And to end today's topic, the usual drawing auto-feedback and refs!

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

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Is this drawing accurate ?
I think the perspective may be a bit off, but apart from that it looks good in regard to what’s known of this mite when fully grown.

I may have simplified a bit the setae coverage compared to what it would precisely look like.

The drawing is a combination of several references since not all of them had the same level of detail.

This specimen could either be male or female since both sexes look identical in dorsal view.

REFERENCES

• Block W., 1976. Oxygen Uptake by Nanorchestes antarcticus (Acari). Oikos 27(2), p. 320–323.

· Klimov P.B., OConnor B.M., Chetverikov P.E., Bolton S.J., Pepato A.R., Mortazavi A.L., Tolstikov A.V., Bauchan G.R. & Ochoa R., 2018. Comprehensive phylogeny of acariform mites (Acariformes) provides insights on the origin of the four-legged mites (Eriophyoidea), a long branch. Molecular Phylogenetics and Evolution 119, p. 105-117.

· Krantz G.W. & Walter D.E., 2009. A Manual of Acarology. 3° Edition, Texas Tech University Press, 816 pp.

· Lindsay K.L. 1972. Nanorchestes antarcticus Strandtmann; a taxonomic description of the instars. Acarologia 13(4), p. 593–606.

· Makol J. & Felska M., 2024. New records of Collembola and Acarina in Antarctica. Pacific Insects 6(3), p. 522-523.

• Sharma P.P. & Gavish-Regev E., 2025. The Evolutionary Biology of Chelicerata. Annual Review of Entomology 70, p. 143–163.

GBIF - Nanorchestes antarcticus
https://www.gbif.org/taxon/45N88

@amypteride.bsky.social Sep 9, 2026, 4:04 PM

Let's dive more in details on this mite, from its morphology, life cycle, distribution, phylogeny and adaptation to face cold, since it's the most southern mite ever recorded!

#Cheliceratime
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@amypteride.bsky.social Sep 9, 2026, 4:04 PM

What time is it? It’s #Cheliceratime !
Today's entry is on Nanorchestes antarcticus, and yes like its name implies, it's a mite native from Antarctica!

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

#mite #arachnid #antarctica #sciart #bugsky
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