Exquisite engraving from 1898 of Phrynus
tessellatus, a Caribbean species of amblypygid or tailless whip scorpion (public
domain)
Readers of a certain age (i.e. my own or older)
will probably recognise that the main title of this ShukerNature article of mine is
a totally shameless parody of the title from a famous comedy song released in 1938 by the
much-loved British war-time singer Gracie Fields, the song in question being 'It's the Biggest Aspidastra in the World!' (I
know, I know, but it was just too fantastic a pun to let pass!).
And here, just in case you were
wondering what one looked like, is an aspidistra (note correct spelling of name) – although, sadly, it's not
the biggest in the world! (© Frank C. Müller/Wikipedia – CC BY-SA 4.0 licence)
Anyway, aspidistras aside (but see this blog article's epilogue for a short note regarding the odd spelling and pronunciation of their name as featured in Gracie's song but nowhere else), just what are
amblypygids?
Illustration of an amblypygid from C.L. Koch's Die Arachniden (1841) (public domain)
I first learned about them as a child when reading the August 1966
issue of the then-monthly (previously-weekly) British magazine Animals,
which contained an article by naturalist R.C.H. Sweeney memorably entitled
''Monsters' of the Caves'. This proved to be an excerpt from his forthcoming
book The Scurrying Bush, and told of his encountering these ostensibly
unearthly creatures while exploring various large, many-tunnelled caves in Tanzania's Mkulumuzi Gorge. Also known as tailless whip
scorpions, amblypygids are arachnids related to the vinegaroons or tailed whip
scorpions, but they look more like exceedingly long-limbed spiders, albeit of
the kind from which nightmares are spawned. In reality, however, they are
basically harmless, lacking both a sting and venom fangs, though they can give
quite a nasty bite with their chelicerae (the principal, inner jaws of
arachnids) or nip with their pincer-bearing pedipalps (the outer jaws of
arachnids).
A vinegaroon or tailed whip scorpion,
exhibiting its posterior whip-tail or flagellum and its elongated first pair of
limbs or whip-legs (© Glenn Bartolotti/Wikipedia – CC BY-SA 4.0 licence)
Whereas the vinegaroons earn their tailed whip
scorpion appellation primarily from their long whip-like tail or flagellum, the
amblypygids earn their tailless whip scorpion counterpart not just from the
fact that they lack any such tail but also from their specialised first pair of
limbs, which are exceptionally long and slender (as they also are but to a much
lesser extent in vinegaroons), thereby possessing a fanciful resemblance to
whips (even though they are not utilised in any comparable manner to such
implements). Indeed, their 'whip limbs' are so inordinately elongate (even by
normal amblypygid limb standards!) that they can measure up to several times the
length of their entire body, and are so fragile that they readily snap off.
Coupling their whip limbs with these extraordinary
arachnids' spider-like overall outward appearance, amblypygids are
sometimes loosely dubbed whip spiders, but in reality they constitute an
entirely separate taxonomic order of arachnids (Amblypygi) from true spiders
(Araneae), just as tailed whip scorpions (Thelyphonida) do from true scorpions
(Scorpiones) (again, these latter two groups are superficially reminiscent of
one another externally, this time due primarily to the posterior tail-like
flagellum of the tailed whip scorpions recalling the posterior sting of the
true scorpions).
And as if matters of taxonomic identity and
affinity were not confused enough already by now in relation to amblypygids,
they are also often mistakenly thought by laypeople to be allied to insects!
The reason for this ostensibly strange assumption is due to a behavioural quirk
they exhibit that is unique to whip scorpions among arachnids but is a major
characteristic of insects. For whereas virtually all other arachnids move using
all eight limbs, the amblypygids run (very rapidly) and scuttle around only on
six legs (just like insects), with their whip limbs, far too fragile and
lengthy to be able to function as locomotory limbs, held upwards and outwards.
An amblypygid from Togo in western Africa, showing the full extent of its whip
limbs (© Notafly/Wikipedia – CC BY-SA 3.0 licence)
In fact, their whip limbs are actually used as
tactile sensory organs, stretched out fully to make contact with their surroundings
amid the stygian environment in which these arachnids usually live (and in
which eyesight is rendered largely obsolete, despite their possessing eight
simple eyes). This activity provides their amblypygid owners with detailed
information concerning obstacles, the nearness of walls, and the width of
cracks in walls or other surfaces into which they can squeeze their wafer-thin,
dorsoventrally flattened body in order to escape or remain hidden from potential
predators. In short, their whip limbs fulfil a similar function in terms of
gauging distances and widths of potential escape routes to the antennae of
insects, and the whiskers or vibrissae of certain mammals, such as cats and
rodents. They are also used to 'feel' for prey (mostly arthropods, including
other amblypygids occasionally, but also small vertebrates sometimes), which once detected is rapidly seized by their much stouter and more powerful outermost pair of
mouthparts, the pedipalps. These in turn hand the prey to, then hold it firmly in place for, the chelicerae to macerate into
liquid form for sucking into the mouth and thence the gut.
Most fascinating of all, however, is that research
studies conducted at Cornell University in New York, USA, and published in December 2017
have suggested that in some species of amblypygid, adult females may actually
use their whip limbs to communicate with their offspring, which in turn may be
doing the same to communicate not only with their mother but also with their
fellow siblings. If so, this is one of the few examples of social interaction
known among arachnids,
Close-up view of a Togo amblypygid's formidable spine-fringed pedipalps
(© Notafly/Wikipedia – CC BY-SA 3.0 licence)
In amblypygids, their pedipalps are also very long
(albeit far less so than their whips), with a series of thorny spines running
along their inner edge, and each pedipalp bears at its tip a noticeably large,
powerful pincer for firmly grasping hold of prey, similar in basic appearance
to the chela of a large crustacean such as a crab or lobster. Just like theirs,
moreover, these can also inflict a not-insignificant skin-puncturing nip to
unwary, intrusive fingers, or noses, of anything posing a threat to the
amblypygid. When the latter is at rest, however, its pedipalps are held
directly in front of, and at right angles to, its mouth, folded back upon themselves.
An amblypygid at rest, with its
pedipalps characteristically folded back upon themselves (© Psychonaught/Wikipedia – CC BY 3.0 licence)
Over 150 species of living amblypygid have
currently been described (plus various fossil forms dating back as far as the Carboniferous Period, over 300 million years ago), and they collectively occur in many tropical and
subtropical regions of the world including Africa, Asia, Latin America, and
Australia, but due to their reclusive behaviour these arachnids are rarely seen
unless specifically searched for, because they are all nocturnal and also spend
much of their time concealed in leaf litter or inside cracks or crevices within
tree bark or the walls and roof of caves – unless moulting. For during moulting,
which happens several times during their lifetime, amblypygids normally hang
downward from cave roofs or other raised surfaces, shedding their old
exoskeleton down onto the ground and remaining suspended until their new exoskeleton
hardens and darkens.
An amblypygid found in a cave in Lanquin, Guatemala (© Nick Johnson/Wikipedia – CC BY 2.0 licence)
Needless to say, however, anyone encountering at
close range such a bizarre-looking creature within the shadowy gloom of a cave or
other dark abode but unfamiliar with their nature could be forgiven for barely
suppressing a shriek of horror, especially if the amblypygid in question is one
of the more substantial species. Even the normally redoubtable American
zoologist, cryptozoologist, and animal collector Ivan T. Sanderson freely
confessed in his book Animal Treasure (1937), detailing his collecting
of animals in West Africa, that he personally considered these particular
arachnids to be loathsome and nightmarish. As they are certainly frightful in
form, albeit quite innocuous in nature, and given that if encountered unexpectedly
in the wild they are liable with their extended whip limbs to stroke the face
of anyone peering unwarily close to them, it is not difficult to understand his
view.
Beautiful vintage illustration of an
amblypygid showing its whip limbs extended, dating back to 1911-1919 (public
domain)
As for size, just how large are the largest
amblypygids? This question leads us into potentially controversial territory,
because the most sizeable species have sometimes been referred to as the
largest of all living arachnids. However, this claim is by no means as
straightforward as it may initially seem, because 'largeness' is not a
quantifiable property of an object.
An amblypygid from Chorao island, Goa, in India (© Biusch/Wikipedia – CC BY 3.0 licence)
The length of an object can usually be directly
measured, using various systems of unit, including the imperial system (inches,
feet, yards, miles, etc) and the metric system (millimetres, centimetres,
metres, kilometres, etc). So too can an object's weight, via units such as ounces,
pounds, stones, and tons (in the imperial system), and milligrams, grams,
kilograms, and tonnes (in the metric system). The same is also true of its area
and its volume. But how do you measure its largeness – what units of largeness exist?
There are no such units, because largeness is a subjective, abstract concept,
not an objective, quantifiable, measurable property. Consequently, when
something is said to be the largest example of its kind, it is often something
that is both the longest and the heaviest of its kind – but there are many
instances when the longest of its kind is not also the heaviest. So which
is then the largest – the longest of its kind, or the heaviest?
Komodo dragon (left) and Salvadori's
monitor (right) – heavier vs longer, so which is larger, and why? (© Dr Karl
Shuker / public domain)
If the heavier of the two contenders also exhibits
a sizeable length, we tend to favour the heavier when talking about the largest,
simply because visually it is more impressive. This is why, for instance, the
much heavier but shorter Komodo dragon Varanus komodoensis is deemed the
world's largest species of lizard, rather than Salvadori's monitor V.
salvadorii, which is longer but much lighter. But again, there are
exceptions, and if surface area considerations are also taken into account the
situation becomes even more complex (should the African plains elephant Loxodonta
africana really be deemed the largest land mammal, for example,
rather than the much taller and more visually impressive yet much lighter
giraffe Giraffa camelopardalis, and how do their respective surface
areas compare?), thereby making judgements concerning the largest of anything
fraught with difficulties and inconsistencies.
As seen here with this Brazilian
example, the limbs of amblypygids are disproportionately lengthy relative to
their body size (most especially their whip limbs, which can be several times
as long as their body) (© KatzBird/Wikipedia – CC BY 2.0 licence)
So, applying this to arachnids, it can be readily
appreciated that we can easily quantify which is the longest species of living arachnid (India's giant forest scorpion Heterometrus
swammerdami, up to 11.9 in long), and the heaviest species of living arachnid (northern South America's goliath bird-eating spider Theraphosa blondi,
up to 6.2 oz),
but not the largest species of living arachnid. The reason why those particular
amblypygids with the longest, heaviest bodies among such arachnids have also been
called the largest species of all living arachnids is that when their whip limbs are
fully extended laterally, the span from whip-tip to whip-tip is far greater
than the leg span of any other arachnid when its longest legs are similarly
extended laterally.
The amblypygid record-holder in this capacity is Acanthophrynus
coronatus, inhabiting caves in Central and northern South America, with
specimens boasting an extremely impressive fully-extended whip-tip to whip-tip
span of up to 27.6 in, and able to prey upon lizards and frogs
comparable in size to itself – it truly is the biggest amblypygid in the world! It is also famous for stridulating with its chelicerae. However, the body length and especially the body weight even of these most
substantial of amblypygids are still much less than those of the most sizeable
scorpions and spiders.
Another sizeable amblypygid, Damon
[formerly Titanodamon] johnstoni from West Africa (public domain)
All of which leads very conveniently to a question
that I've been asked on more than one occasion by fellow fans of the Harry
Potter series of movies. In Harry Potter and the Goblet of Fire,
bringing to the big screen the eponymous fourth novel in J.K. Rowling's
celebrated Harry Potter heptalogy, during a lesson at Hogwarts in which the
three Unforgivable Spells are being demonstrated, the teacher in question, ostensibly
Alastor 'Mad-Eye' Moody (though in the climax of the book and movie it is
revealed that this is not Moody at all but is in fact Barty Crouch Jr impersonating
him using Polyjuice Potion), applies the spells to what many viewers have
simply assumed to be a made-up, non-existent spider-like monster, but which is
actually an amblypygid. It is also placed on pupil Ron Weasley's head - much to Ron's evident horror! However, this amblypygid is far larger in every way – body length,
body width, and limb length – than even the mighty A. coronatus. How is
that possible? In fact, this very imposing on-screen amblypygid was entirely
computer-generated – during which process the fundamental form of a real
amblypygid was recreated, but with its proportions greatly enlarged in order to
make it look more monstrous.
Screenshot from Harry Potter and
the Goblet of Fire (screenshot obtained here) depicting Ron Weasley (played by Rupert Grint) not
enjoying his exceedingly close encounter with the giant amblypygid (© J.K.
Rowling/Mike Newell/Heyday Films/Patalex IV Productions/Warner Brothers
Pictures – reproduced here on a strictly educational non-commercial Fair Use
basis for the purposes of review only)
Finally: it may come as something of a surprise to
ShukerNature readers who were not previously familiar with amblypygids, but
these somewhat alienesque arachnids can be obtained through the pet trade and
actually make good pets, although the most commonly-kept pet species is Damon
diadema from Tanzania; the much bigger A. coronatus does not fare
well in this capacity and therefore is not generally available commercially. As
long as they are well-fed and suitably housed in large glass enclosures with
all environmental requirements (especially temperature, humidity, substrate, and
hiding places) fully met, amblypygids are generally quite docile, much more so
than any other type of large arachnid.
Having said that: in a video clip that was recently
doing the rounds on social media, a captive amblypygid specimen belonging to
the extremely large Tanzanian species Euphrynichus amanica was being teased
by its presumed owner in order to incite it to extend its lengthy pedipalps and
snap their pincers at the owner's finger for the camera, which the distraught
amblypygid, being forced to adopt a defensive mode, duly did on several
occasions, but backing away whenever possible from what it perceived to be a threat
from the finger. Finally, the owner closed their hand over the amblypygid and
picked it up, and after a few seconds its pedipalps could be seen to move down
onto the owner's little finger, whereupon the owner abruptly and visibly
flinched before swiftly placing the amblypygid back down and looking at their finger.
The pedipalps' movements were too rapid to be absolutely certain of what
happened, but after freezing the relevant frame it looked to me as if the unsettled amblypygid
had pinched its owner's finger with at least one if not both of them – an
action that according to descriptions elsewhere apparently elicits the
sensation of having a thorn piercing the skin. (Incidentally, a version of this
video clip was uploaded onto YouTube on 7 March 2016 and can currently be viewed here,
but I wish to point out that there is no suggestion anywhere that the person
who uploaded it is actually the person featured in it; indeed, what looks like
the same specimen and owner also appear in a different YouTube video clip
uploaded a month earlier by a seemingly different person and viewable here.)
An amblypygid in El Yunque National Forest,
Puerto Rico – as
readily seen here, a nip from amblypygid pedipalps like these, while not
dangerous, is nonetheless not recommended! (© George Gallice/Wikipedia – CC BY 2.0 licence)
And the moral of this incident? Never antagonise an
amblypygid!
Amblypygids make interesting and
docile pets if treated kindly (© Caspar S/Wikipedia – CC BY 2.0 licence)
EPILOGUE: PEDANTS' CORNER
Yes, I am indeed aware that on both the original 78 rpm record and the sheet music to the afore-mentioned Gracie Fields comedy song from 1938, the name of the titular plant was spelt 'Aspidastra', not 'Aspidistra', and that Gracie even pronounced it that way when singing the song. Nevertheless, this spelling and her pronunciation were incorrect, but nowhere have I been able to discover how and why such an error arose, nor why it was perpetuated and never corrected. And as Gracie herself passed away in 1979, it may well remain a mystery indefinitely.
Gracie Fields in 1937, a year before her famous botanically-themed song was released (public domain)
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