Vermiform

Vermiform (pronounced vur-muh-fawrm)

Resembling or having the long, thin, cylindrical shape of a worm; long and slender.

1720-1730: From the Medieval Latin vermiformis, the construct being vermis (worm) + forma (form).  Vermis was from the primitive Indo-European wr̥mis and cognates included the Ancient Greek ῥόμος (rhómos) and the Old English wyrm (worm (which evolved into the Modern English worm)).  Form was from -fōrmis (having the form of), from fōrma (a form, contour, figure, shape, appearance, looks).  The root of the Latin vermis was the primitive Indo-European wer- (to turn, bend), an element most productive, contributing to: adverse; anniversary; avert; awry; controversy; converge; converse (as the adjectival sense of "exact opposite”); convert; diverge; divert; evert; extroversion; extrovert; gaiter; introrse; introvert; invert; inward; malversation; obverse; peevish; pervert; prose; raphe; reverberate; revert; rhabdomancy; rhapsody; rhombus; ribald; sinistrorse; stalwart; subvert; tergiversate; transverse; universe; verbena; verge (as the verb meaning "tend, incline"); vermeil; vermicelli; vermicular; vermiform; vermin; versatile; verse (in the sense of the noun "poetry") version; verst; versus; vertebra; vertex; vertigo; vervain; vortex; -ward; warp; weird; worm; worry; worth (in the adjectival sense of "significant, valuable, of value") worth (as the verb "to come to be"); wrangle; wrap; wrath; wreath; wrench; wrest; wrestle; wriggle; wring; wrinkle; wrist; writhe; wrong; wroth & wry.  Vermiform is an adjective.

Commonly used in medicine to describe the appendix, Modern French also gained the word from Latin as the adjective vermiforme (plural vermiformes), the spelling of the medical use apéndice vermiforme (plural apéndices vermiformes).  The only known derived form in English is the adjective subvermiform, used apparently exclusively in the disciplines of zoology, including entomology.  The meaning was defined in a dictionary from 1898 as “shaped somewhat like a worm” which is surprisingly imprecise for the language of science but that vagueness appears adequate for the purposes to which it’s put.  For whatever reason, vermiform was a word much favored by the US humorist HL Mencken (1880-1956).

The female Eumillipes persephone: 1,306 legs & 330 segments.  

Because the scientific literature has for some time been dominated by COVID-19 and all that flowed the brief, sudden prominence of two vermiform creatures, one ancient, the other more recent, was an amusing distraction.  The younger animal was a new species of millipede which boasted not only more legs than any other creature on the planet but was the first of its kind to live up to its name.    

Since circa 1600, the term millipede has been applied to any of the many elongated arthropods, of the class Diplopoda (a taxonomic subphylum within the phylum Arthropoda (the centipedes, millipedes and similar creepy-crawlies) with cylindrical bodies that have two pairs of legs for each one of their many body segments and, although milliped was long regarded as the correct spelling by scientists who work with myriapods, millipede is by far the most common form in general use (although there’s the odd specialist who insists on millepede).  Millipede was from the Latin millipeda (wood louse), the construct being mille (thousand) + pes (genitive pedis) (foot), from the primitive Indo-European root ped (foot) (probably a loan-translation of Greek khiliopous).  When named, it wasn’t intended as a mathematically precise definition, only to suggest the things had lots of legs though, certainly many fewer than a thousand.  The creature has always possessed a certain comical charm because, despite having usually twice the number of legs as centipedes, the millipede is entirely harmless whereas there are centipedes which can be quite nasty.  For centuries millipede was thought a bit of a misnomer, with no example ever observed with more than 750 legs and that deep-soil dweller was an outlier, most having fewer with a count in two figures quite common.  The new species also lives in the depths: Eumilipes persephone (Persephone, the daughter of Zeus who was taken by Hades to the underworld), a female was found to be sprouting 1,306 legs.  Pale and eyeless, it’s vermiform in the extreme, the body-length almost a hundred times its width and instead of vision, it used a large antennae to navigate through darkness to feed on fungi.

The sheer length of the thing does suggest a long lifespan by the standards of the species, most of which tend not to survive much beyond two years.  The persephone however, based on a count of the body segments which grow predictably in the manner of tree rings, seems likely to live perhaps as long as a decade.  One factor which accounts for the longevity is the absence of predators, the persephone’s natural environment banded iron formations and volcanic rock some 200 feet (60 m) beneath the surface of a remote part of Western Australia.  Entomologists didn’t actually venture that deep to explore, instead using the simple but effective method of lowering buckets of tempting vegetation down shafts drilled by geologists exploring for minerals, returning later to collect whatever creatures had been tempted to explore.

Artist’s impression of an Arthropleura: half a metre wide and perhaps nearly three metres in length, the latter dimension similar to a small car.  

Days after the announcement from the Western Australian desert, livescience.com also announced researchers in the UK found the fossilized exoskeleton of an Arthropleura, the largest arthropod yet known to have lived.  The length of a modern car, the giant millipede-like creatures appear to have done most of their their creeping and crawling during the Carboniferous Period, between 359 million and 299 million years ago.

Although the Arthropleura have long been known from the fossil record, there’d not before been any suggestion they ever grew quite so large and the find was quite serendipitous, discovered on a beach in a block of sandstone which had recently fallen and cracked apart.  The exoskeleton fragment is 30 inches (750 mm) long and 22 inches (550 mm) wide which means the giant millipede would have been around 102 inches (2600 mm) long and weighed around 110 lbs (50 kg)m making it the biggest land animals of the Carboniferous era.  Despite its bulk however, the physics of movement and the need to support its own weight mean the leg count is nowhere near as impressive as its young relation what is now on the other side of the world (what are now the Australian and European land masses were closer together during the Carboniferous) and it’s still not clear if Arthropleura had two legs per segment or every two segments but either way it adds up to much fewer than a hundred.

Ultimately, Arthropleura was a victim of changing conditions.  In its time, it would have been living in a benign equatorial environment but, over millions of years, the equator can shift because of the phenomenon of TPW (true polar wander) in which the outer layer of Earth shifts around the core, tilting the crust relative to the planet’s axis.  This last happened some eighty-four million years ago.  So, the conditions which for so long had been ideal changed and changed suddenly and Arthropleura was unable to adapt, going extinct after having flourished for nearly fifty-million years.  The reasons for their demise are those seen repeatedly in the fossil record: In an abruptly changed environment, there was suddenly more competition for fewer resources and the Arthropleura lost out to animals which were stronger, more efficient and better able to adapt.

The human appendix.

Thousands of years after first being described, the human appendix, a the small blind-ended vermiform structure at the junction of the large and the small bowel remains something of a mystery.  For centuries the medical orthodoxy was it vestigial, a evolutionary dead-end and a mere quirk of human development but the current thinking is it exists as a kind of “safe-house” for the good bacteria resident in the bowel, enabling them to repopulate as required.  However, being blind-ended, although intestinal contents easily can enter, in certain circumstances it can operate as a kind of one-way, non-return valve, making exit impossible which results in inflammation.  This is the medical condition appendicitis and in acute cases, the appendix must surgically be removed.  That's usually fine if undertaken in good time because it's a simple, commonly performed procedure but unfortunately, in a small number of cases, a residual "stump" of the structure may escape the knife and in this inflammation may re-occur, something surgeons resentfully label “stumpitis”.  Apparently the most useless part of the human anatomy, there is noting in the medical literature to suggest anyone has noticed any aspect of their life being changed by not having an appendix.