Minxy Cottonsocks and the evolution of dropgorgons and other winged cats

If anything should be clear from the range of creatures that I write about at Tet Zoo - think caecilians, borhyaenoids, imaginary giant owls and rhynchosaurs - it's that there's an almost infinite amount of technical information on obscure creatures 'locked away' in the technical literature. Among the most remarkable of mammals are, without doubt, the winged cats or pantheropterygines, yet for all their fame and notoriety, most of the information on these creatures has remained widely scattered in the literature and a good synthesis is absent.

Winged cats were first brought to scientific attention in 1891 when Richard Lydekker named Pantheropteryx anglicus for the famous London Zoo specimen. Known to her keepers as Minxy Cottonsocks, she'd been discovered in the Banister, Walton & Co. builder's yard in Trafford Park, Manchester, in 1880, and then sent to London Zoo [Minxy is shown above]. Though Minxy became a popular attraction (well known for her fantastic 15-metre leaps), the deaths of several keepers at her vicious claws made the zoo keen to dispense with her. In 1882 she was purchased by P. T. Barnum at the same time as Barnum obtained Jumbo the elephant; Jumbo and Minxy were actually close friends, and when Jumbo was killed by a train on arrival in New York, Minxy went into mourning and hid for weeks in a pigeon loft. After the sale of Barnum's exotic cat collection in 1889 (Cherrio the famous cherry-coloured cat, Manglox the five-legged leopard and Parsley the vegetarian lion were also included in the lot), Minxy ended up back at London Zoo, and here she lived until her suspicious death in 1890.

P. anglicus specimens had, of course, been known long prior to the publication of Lydekker's paper (Lydekker 1891) - Athanasius Kircher famously illustrated one as early as 1667 [his illustration is shown here] - but they'd generally been dismissed as one-off freaks or even as hoaxes. Well, ha ha ha, how we laugh at those naïve suggestions now. A remarkable succession of fossils, and the discovery that the dropgorgons of ancient Eurasia are members of the pantheropterygine clade, have shown that winged cats are one of the most remarkable and divergent lineages within the carnivoran radiation.

Winged cats have, of course, gotten some attention in the popular media (who can forget the 13-part TV series Skypuss!), but the full story behind the palaeontology, developmental genetics and molecular phylogeny of Pantheropteryginae has gone unreported outside of the technical literature. Karl Shuker has provided a series of extremely useful reviews of winged cat history (e.g., Shuker 2008), but his work is marred by his interpretation of winged cats as normal members of the domestic cat lineage afflicted by a hypothetical condition dubbed feline cutaneous asthenia (FCA) (see also Patterson & Minor 1977). The FCA hypothesis has become the bane of research on extant winged cats, allowing some misguided animal carers to surgically remove the wings of their cats. I'd compare this to snipping the wings off angels and cherubs, except those things don't exist.

Pantheropteryx = surprisingly anachronistic and conservative!

It is rather ironic that P. anglicus was the first winged cat taxon to be discovered, as phylogenetic analyses show that it represents one of the oldest divergences within the winged cat clade (Ramsburger et al. 2001) [simplified version of the Ramsburger et al. phylogeny shown above]. Furthermore, it belongs to a strikingly conservative lineage and seems to have undergone little change over its 30 60 many millions of years (Graur & Martin 2004) of evolution. The discovery of additional pantheropterygines has demonstrated that the wings of Pantheropteryx are proportionally small compared to those of other species, and are only stiffened internally by cartilage. Indeed, P. anglicus is so similar to true cats of the domestic cat lineage that members of its species have (when mutilated or injured) often been mistaken for feral domestic cats.

Some experts even suspect that the type specimen for the domestic cat Felis catus - Carl von Linné's pet moggy Maximilian III - might really be a P. anglicus specimen with cropped wings (for a review of Linné's well documented and rather sickening obsession with cropping the wings off winged cats, see French (1980)) [von Linné and Maximilian III shown in the adjacent image; both pics from wikipedia]. Kitchener (1988) proposed that, if Maximilian III does turn out to be a mistakenly identified P. anglicus specimen, the International Commission on Zoological Nomenclature (ICZN) will be petitioned to elect a new type specimen that actually really does belong to F. catus. Brunet & McGee (1990) argued that it might be quicker to circumvent the slow, tortuous ICZN route, and that both Maximilian III, and the complete published works of Linnaeus, should be discarded in a ceremonial bonfire. An early plan to analyse Maximilian III's DNA was scuppered when Lewis (1999) pointed out that Linné used distilled flying cat oil to embalm his taxiderm specimens. I asked a colleague how widespread the use of flying cat oil was in the 18th century taxidermy business. "Pretty widespread", he said.

Anatomy of a cat wing - - oops, I mean a cat AIDO

For some time the mechanism behind the evolution of what appeared to be a third set of limbs in a tetrapod was regarded as an irresolvable enigmatic mysterious uber-problem. Observations of winged cats in captivity and in the wild show that they do use the wings to glide; they can actually increase the length of a leap by holding the wings outstretched (Femes et al. 1991).

Because the use of the term 'wing' has - to some - implied homology with limbs, some workers have argued that we really should use a different name for the structures. Verbosio (2002) proposed the term aerodynamic integumentary dorsal organs, or AIDOs, for the 'wings', in order to circumvent this issue. Cartilaginous rods within the AIDOs provide stiffness and, combined with the stiff, feather-like organs dubbed feloplumous integumentary structures (or FISs), produce an aerodynamic effect. The wing cartilages represent neomorphs and are known variously as AIDO spar sections or AIDOSSs and neomorphic cartilaginous rods or NCRs. A big question remains: did the AIDOs and their associated FISs evolve first (perhaps for use in display, intimidation or thermoregulation), with the AIDOSSs and NCRs being opportunistic structures that evolved later on (if this is true, then the role of AIDOs as aerodynamic organs could be an exaptation)? Or... were AIDOSSs and/or NCRs there from the start, in which case AIDOSSs, NCRs and FISs drove the evolution of AIDOs all along? There's a load of evo-devo literature on this but it bores me to tears so I don't want to talk about it [P. anglicus AIDO shown in the adjacent image; Dropgorgon AIDO shown below].

Flapperailurus shows that AIDOSSs and NCRs had appeared within the AIDOs by the Pliocene (Verbosio (2002) provided yet another new term - neomorphic ossified rods or NORs - for these), and it's inferred that simple bones like those seen in this taxon became elaborated over time, eventually giving rise to the branched NORs present in the wings of Roflailurus, Slooflirpapuss and the dropgorgonids.

The remarkable dropgorgonids

Without doubt the most remarkable pantheropterygines - and arguably the most remarkable of all mammals - are the dropgorgonids (often just called dropgorgons) of Pliocene and Pleistocene Eurasia and Africa. Of the several known taxa, Tnihevissam of Romania, Chinnychinpuss of China, and Dropgorgon (known from several species that occurred across Europe, Asia, the Middle East and northern Africa) seem to form a morphological sequence in which body size increased, the anterior dentition became hypertrophied, the cranium became increasingly bulbous and the brain more enlarged, and the limbs became more robust (Kurtén 1956). The culmination of this trend was the incredible, facultatively bipedal Dropgorgon, the surreal skull of which was originally assumed to be pathological (Dawkins & Sanford 1869) prior to the discovery of additional specimens [skull shown here, from Dawkins & Sanford (1869)].

Dropgorgon giganteus was a truly formidable beast. A large male would be more than 3 m tall when standing bipedally, 5 m long, have a wingspan exceeding 6 m, and weigh over 200 kg. The frequent occurrence of its remains in caves and steep-sided ravines indicate that it really inhabited such places, and chewed bones found in these dropgorgon 'lairs' show that it ate goats and humans. Dawkins & Sanford (1869) surmised that it dropped down on prey from above in drop-bear-like style, and this inferred behaviour explains the name they chose for it (incidentally, this demonstrates that drop-bears were known to Europeans long prior to the 21st century!). Dawkins & Sanford (1869) included D. giganteus among the felids, but a link with the other pantheropterygines wasn't realised until Chinnychinpuss gansuensis from China and the good Dropgorgon postcranial remains from Turkey were discovered in the 1980s.

Radiocarbon dating has shown that D. giganteus survived in central and eastern Asia well into the Holocene and to as recently as the 5th century. The relatively recent existence of this enormous, monstrous, long-winged predator has not been lost on folklorists and classicists who have drawn attention to the many similarities this animal has with griffons (Griffen 1997). We're never really going to know whether the griffons of mythology really were based on dropgorgons, but I agree that this is a very real possibility. Griffen (1997) also drew attention to the strong similarity that dropgorgons have with various creatures from African folklore, notably the Sasabonsam from Ghana, and the Kikiyaon and Guiafairo of Senegal. If this is correct, it raises the exciting possibility that one or more dropgorgon species awaits discovery in the zooarchaeological record of tropical Africa.

Due to their remarkable morphology and behaviour, dropgorgons and other pantheropterygines have been important animals in the history of zoological discovery, and their story is an incredible one. Where else could you read about a controversial zoo specimen from the 19th century that once belonged to P. T. Barnum, about the evolution of entirely novel wing-like organs, and about obscure monsters from African folklore? Yet I've hardly scratched the surface of the pantheropterygine literature; hopefully this brief introduction has piqued your interest.

Refs - -

Brunet, J. J. & McGee, T. 1990. Thinking the unthinkable: a neat and tidy proposed resolution to an inextricable problem of historical taxonomy concerning the first winged cat. Proceedings of the American Winged Cat Society 67, 45-60.

Dawkins, W. B. & Sanford, W. A. 1869. The British Pleistocene Mammalia. Part III. British Pleistocene Felidae. Palaeontographical Society, London.

Femes, B., Dorchap, E. & Gerwih, H. 1991. They seem to glide. Are there aerodynamic effects in leaping winged cats? Zeitschrift fur Morphologie und Catologie 79, 37-385.

French, G. W. 1980. Carl von Linné was one sick mother: a secret obsession with cat mutilation revealed through pictograms and retrogressive astrology. The Smudgener 1, 5-8.

Graur, D. & Martin, W. 2004. Reading the entrails of chickens: molecular timescales of evolution and the illusion of precision. Trends in Genetics 20, 80-86.

Griffen, M. 1997. The discovery of dropgorgonid cats brings an end to the griffon mystery. Pokemonia 34, 38-46.

Kitchener, B. 1988. What a sodding mess: the status of the type specimen of Pantheropteryx anglicus and why YOU should care. Taxonomy, Taxonomy, sigh, Taxonomy 250, 129-140.

Kurtén, B. 1956. A case of Darwinian selection in dropgorgon flying-cats. Evolution 10, 412-416.

Lewis, O. 1999. Carl von Linné used distilled flying cat oil to embalm his taxiderm specimens. Taxidermy Now 46, 10-12.

Lydekker, R. 1891. On an aeluroid carnivore from the United Kingdom, notable for its wings. That is correct, I said wings. It is a freakin' winged cat for crying out loud. This is one paper that you really should read, you know. Proceedings of the Zoological Society 20, 883-900.

Patterson, D. F. & Minor, R. R. 1977. Hereditary fragility and hyperextensibility of the skin of cats. A defect in collagen fibrillogenesis. Laboratory Investigation 37, 170-179.

Ramsburger, D., Slice'n'dice, M. & Groovy, E. 2001. Holy shit!! A phylogeny for winged cats reveals amazing stuff, hence this two-page paper. Science 308, 1112-1113.

Shuker, K. P. N. 2008. Dr Shuker's Casebook. CZF Press, Bideford.

Verbosio, H. 2002. Patterns of variation in the 'wing' morphology of dropgorgonid carnivorans: developmental constraints, size, and phylogenetic history. Journal of Experimental Zoology (Mol Dev Evol) 303B, 135-147.