#schizomida

My population of Schizomida (parthenogenic tailless whipscorpions) are so happy in their box of dirt. As always, tending a box of dirt is such a good decision and I recommend it.

(Sources - 1, 2, 3, 4)

Order: Schizomida

Common Name: “short-tailed whip-scorpions” or “sprickets”

Families: 2 - Hubbardiidae and Protoschizomidae

Anatomy: cephalothorax is divided into three regions, each covered by plates; abdomen is a smooth oval of 12 segments; large, well-developed, pincer-like pedipalps; first two legs are modified sensory organs and are not used for walking; very short telson consisting of no more than 4 segments (females have 3-4, males have 1); body is relatively soft and unarmored; hind legs are modified for jumping as part of their escape response when threatened; no actual eyes, but a few species have vestigial eyespots capable of telling light from dark

Diet: smaller invertebrates, such as isopods, millipedes, cockroaches, worms, springtails, termites, booklice, zorapterans, and other schizomids

Habitat: tropical and subtropical regions in Southeast Asia, India, Australia, several Pacific Islands, Central and South America, and Africa; additionally, some populations have been found in neighboring temperate regions such as California and Texas in the US, and some can be found in humid greenhouse environments in Europe; they can typically be found in rainforest leaf litter, in the top layer of organic soil, under rocks, in and beneath rotten logs, and in caves

Evolved in: Late Cretaceous

(source)

Propaganda under the cut:

this little lady is Stenochrus portoricensis, collected from nonnative populations in South Florida. like their larger relatives the vinegaroons/whipscorpions, they can spray a defense chemical cocktail that includes acetic acid (vinegar) from the base of their flagellum, but only a tiny droplet of it because of their size!

schizomids are eyeless, using their antenniform legs to feel their way through the cracks between soil particles on the hunt for tiny prey like springtails and mites. even at ~3mm long, they’re precise and effective predators, leaping onto prey with muscular hind legs and seizing it with raptorial pedipalps.

Photos 1-2 - Notozomus ker, female

Photos 3-4 - Notozomus ker, male

Schizomida arachnids (or Shorttailed whipscorpions), identified on iNaturalist as N. ker. using information from Harvey (1992).

For whatever reason there's a lacklustre amount of Australian Schizomida observations on iNaturalist. There's a wide variety of Australian Schizomids out there, with many new species being uncovered fairly recently in Abrams et al. (2019) for example.

Any sort of public record of these arachnids (or just terrestrial arthropods in general) will be very useful, especially since, in general, iNaturalist is lacking observations of Schizomida. Abrams et al. (2019) mentions that there are roughly 350 species of Schizomid out there, but so far, only 23 have been identified on iNaturalist. I feel iNaturalist provides good public records, so the more available on the website, the better.

I'm going to continue flipping over rocks and rotten logs for more Schizomids (and creatures in general), and I implore others to do the same. There's a lot that can be found hiding in the mulch.

*BTW these are not spiders, they're a different Chelicerate entirely.

Sources and further reading:

Harvey, MS 1992 'Schizomida (Chelicerata) of Australia', Invertebrate taxonomy, vol. 6, no. 1, pp. 77-129.

Abrams, KM, Huey, JA, Hillyer, MJ, Humphreys, WF, Didham, RK, Harvey, MS 2019, 'Too hot to handle: Cenozoic aridification drives multiple independent incursions of Schizomida (Hubbardiidae) into hypogean environments', Molecular phylogenetics and evolution, vol. 139, p. 106532.

24/10/23 - Schizomida: Notozomus ker

Whip-spricket (Paradraculoides eremius)

The Short-tailed Whip Scorpion, Hubbardia briggsi, found beneath rocks on a hillside in Fresno, CA, USA.

That is how the Schizomida (short-tailed whip scorpions) do.

Found this nugget-sized leggy arachnid in some pine litter in south Florida where they're native. 🥹