The Fabrosaur Heresies

A Triassic scene from the Meyers Konversations-Lexikon, a 19th-20th Century German publication (4th edition, 1885). In the public domain. Modified from the original retrieved from Wikimedia Commons.

What would your reaction be if I told you that there was a dinosaur family... that never existed? If you have much familiarity with the science of classifying organisms, then you shouldn't be very surprised at all. Our taxonomies are, after all, ephemeral little things, at best only convenient labels for the diversity we see in the natural world, and never a perfect reflection of reality. It often turns out, especially when considering long-extinct taxa like non-avian dinosaurs, that even important or well-known groups eventually turn out to be hopelessly poly- or paraphyletic, or else to be based on such little solid material that they end up being scientifically useless. With these prospects in mind, same as the last time we talked about murky archosaurian taxonomy, we'll be delving back into the Triassic, that most complicated of time periods. There we'll consider just one such problem - that there's something wrong with our fabrosaurs...

From the start of modern science's efforts to understand the Triassic period (252 - 201 Ma), unraveling the mystery surrounding the origin of dinosaurs has been a singular obsession of many researchers. Somewhere in the space of the Middle and Late Triassic, the first true dinosaurs split away from the other archosaurs, and quickly began to diversify into the familiar clades which would soon come to dominate the remainder of the Mesozoic. Among many other examples, true sauropods first emerged toward the end of this period, and it's likely that tetanuran theropods (the "advanced theropods", that is, all theropods closer to birds than to ceratosaurs) did as well.

The deepest division within Dinosauria, and the one which is the least well understood, is that between the saurischians and ornithischians, which must have occurred deep in the Middle Triassic. Despite the numerous saurischian dinosaurs known from the Triassic, however, ornithischians are comparatively sparse, which makes deciphering their early history difficult. Here and there, however, fossils from the Late Triassic and Early Jurassic have turned up to give us a glimpse at the base of the ornithischian tree. Most of these were found during the course of the 20th Century as dinosaur research began to pick up once more after the Second World War, and so it is this period which, until recently, shaped our understanding of the ornithischians' earliest days. In an era of palaeontology when it was still fashionable to call more or less any small ornithopod a hypsilophodontid, it was tempting to find a place for these basal ornithischians in the dinosaurian scheme, and what better way than to slot them into a convenient, family-level grouping?

Enter the Fabrosaurs

A replica of the Lesothosaurus diagnosticus holotype, housed at the Royal Belgian Institute of Natural Sciences, Brussels and photographed by Wikimedia user "Ghedoghedo". Original retrieved from Wikimedia Commons.

Happily, in 1972, just the right label came along. Named principally for the scrappy remains of a South African dinosaur called Fabrosaurus (after Jean Fabre, the French palaeontologist whose efforts uncovered the holotype), Fabrosauridae eventually expanded from a somewhat redundant single-species family grouping to a rather popular label for further ornithischians found from Late Triassic and Early Jurassic strata. For a long time, Lesothosaurus, from the same general time and place as Fabrosaurus (199-189 Ma, Early Jurassic), was also held to be a member of this clan. Known from much more substantial remains than the scant Fabrosaurus, Lesothosaurus informed many a Triassic diorama of scampering "fabrosaurs", running and leaping across the landscape of the imagination. Agilisaurus from the Middle Jurassic of China joined the ensemble as a late-surviving member when it was originally described as a fabrosaurid, and a smattering of suspiciously ornithischian-like teeth from the Late Triassic of North America which received the moniker Revueltosaurus claimed new ground for the group. On all fronts, geographical and temporal, the mighty Fabrosaur Empire seemed to be expanding, joining Triassic dioramas everywhere as a forerunner of sorts to the later, more advanced ornithischian groups which would populate scenes of the Jurassic and Cretaceous. Alas...

The Fall of the Fabrosaur Empire

The incriminating teeth of Revueltosaurus callenderi. Originally photographed by the (American) National Park Service and retrieved from Wikimedia Commons.

From the start, there were problems. The only fabrosaur with remains worth writing home about was Lesothosaurus, which placed the diagnosis of the grouping on a pretty shaky foundation. It was therefore easy (and tempting) to assign any tiny scraps of ornithischian from the first half of the Mesozoic to Fabrosauridae, making the group seem less a mighty empire, and more a kingdom of bits and pieces. As early as the beginning of the 1990s, as the Dinosaur Renaissance entered full swing, palaeontologists were already expressing doubts about the validity of the family as a whole, given the uncertain validity of Fabrosaurus itself. Bit by bit, pieces of fabrosaur material ended up being reassessed as belonging to heterodontosaurs (on which more another time) or even as prosauropods. Most incriminatingly, the ever-important Revueltosaurus material expanded to several skeletons, betraying its shocking identity as not even a dinosaur, but a crocodile-line archosaur close to aetosaurs. As a killing blow of sorts, more complex cladistic analyses after the turn of the century split up what was left, leaving Lesothosaurus as perhaps the sister taxon to thyreophorans (the "armored dinosaurs", ankylosaurs and stegosaurs), and Agilisaurus as closer to the base of the ornithopods and marginocephalians. The sun, it seemed, had set on the fabrosaurs.

Will the Fabrosaurs Rise Again?

Lesothosaurus diagnosticus. Illustrated by Jack Wood and retrieved from Wikimedia Commons.

Well, no, probably not - at the very least, not in the same way that they were before. "Fabrosauridae" is defined around its type species, Fabrosaurus australis, which most researchers now consider a dubious taxon. Even if more complete and diagnostic material of the same animal turned up, it would be difficult to assign it to Fabrosaurus with confidence given how little there already is to work with. However, all is not lost, for the Triassic ornithischians are not altogether gone. Pisanosaurus from the Late Triassic of Argentina and the slightly younger Eocursor of South Africa still firmly place the ornithischians within the Triassic period. However, the loss of Revueltosaurus means that these two taxa, plus some unnamed heterodontosaurid remains also from Argentina, are the only confirmed ornithischian remains from the Triassic period, and all are localized to a small part of the then-extant supercontinent of Gondwana. Since the earliest saurischian dinosaurs are also known from South America, it is not surprising that the ornithischians, too, found their origins in the same place. The question of why ornithischians seem to be so scarce in the northern continents during this time when compared with saurischians is, as of yet, unanswered, but more Triassic ornithischians surely remain undiscovered, and it's wholly possible that some will turn up from Laurasia and make us reconsider the early history of the ornithischians all over again.

And, who knows? Perhaps some very close relatives of Lesothosaurus, the last true fabrosaur, will turn up in Africa or elsewhere in the future. The lesothosaurs could well rise from the ashes of the fallen empire and shake off the dust to scamper anew across our Triassic scenery and feed a new generation of over-ravenous theropods. It's nice to dream...

For more confusing Triassic business:

• The Curious Case of Crurotarsi

For more ornithischians:

• The 'Duckbill' Stomp

Sources:

• Bonaparte, J. F. "Pisanosaurus mertii Casamiquela and the Origin of the Ornithischia." Journal of Paleontology 50, 5. 1976.
• Butler, Richard J., Roger M. H. Smith, and David B. Norman. "A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia." Proceedings of the Royal Society B 274. 2007.
• Butler, Richard J., Paul Upchurch, and David B. Norman. "The phylogeny of the ornithischian dinosaurs." Journal of Systematic Palaeontology 5. 2008.
• Irmis, Randall B., William G. Parker, Sterling J. Nesbitt, and Jun Liu. "Early ornithischian dinosaurs: the Triassic record." Historical Biology 19(1). 2007.
• Parker, William G., Randall B. Irmis, Sterling J. Nesbitt, Jeffrey W. Martz, and Lori S. Browne. "The Late Triassic pseudosuchian Revueltosaurus callenderi and its implications for the diversity of early ornithischian dinosaurs." Proceedings of the Royal Society B 272. 2005.
• Sereno, Paul C. "Lesothosaurus, “Fabrosaurids,” and the early evolution of Ornithischia." Journal of Vertebrate Paleontology 11. 1991.

Lost Solitaires of the Hawaiian Islands

Three Hawaiian solitaires. Top to bottom: Kāma'o (Myadestes myadestinus), Oloma'o (M. lanaiensis), and Ōma'o (M. obscurus). Illustrated by John Gerrard Keulemans between 1893 and 1900. Retrieved via Wikimedia Commons.

In terms of the world's most biodiverse regions, the Hawaiian islands of the central Pacific have had a spectacularly bad run of luck over the past ten centuries. As with many of the world's oceanic islands, the Hawaiian Archipelago, some 2,500 miles (4,000 km) away from the nearest continental landmass, is home to numerous endemic species, including plants, invertebrates, and birds. With hunting and the introduced Polynesian rat (Rattus exulans) arriving on the archipelago with the first human settlement (between about 500 and 1300 CE), a number of ground-dwelling birds with vulnerable nesting sites, such as the massive moa-nalo waterbirds, disappeared. Later European exploration, conquest, and settlement on the islands brought a host of introduced Old World and New World species alike, which visited further devastation still on Hawaii's endemic species. Mammals like mongooses, pigs, and cats (and the Toxoplasma bacteria carried by the latter, which alone has devastated many native species) have wreaked untold havoc, especially on the native bird life. Only six passerine lineages seem to have made it to Hawaii in its history. Of these, one (Mohoidae, the Hawaiian honeyeaters) is now entirely extinct, the only avian family to have become so in the modern era. Another, Hawaii's sole native corvid, the Hawaiian crow or 'alalā, is currently extinct in the wild and persists only in captivity. Of Hawaii's two sylviids ("Old World warblers") one is extinct and another critically endangered. Even out of the largest of the endemic passerine groups, the Hawaiian honeycreepers (fringillid finches of the subfamily Carduelinae), a great number of species are either extinct or in danger of extinction. Hawaii's three monarch flycatcher species (Monarchidae) seem to have fared the best, by contrast, but on the whole it wouldn't be too great an exaggeration to say that all of Hawaii's native songbirds are in dire straits indeed. But more on these other groups another day - the sixth lineage is comprised of Hawaii's five thrushes, which will be the focus of today's post.

For a long time, the Hawaiian thrushes were grouped together in the unique genus Phaeornis, but closer analysis has instead borne out the conclusion that they are nested within Myadestes, the solitaires. American readers might be familiar with this genus in the form of Townsend's solitaire (M. townsendi), or Mexican readers with the brown-backed solitaire (M. occidentalis). Other members of this clade are found in the Caribbean, Central America, and into South America as far south as Bolivia. The solitaires' closest relatives are the bluebirds (Sialia) and, more distantly, West African thrushes in the genus Neocossyphus. It seems likely that Neocossyphus thrushes disseminated across the Atlantic Ocean from within the ancestral Neocossyphus-Myadestes-Sialia clade, given that the Myadestes solitaires crossed the Pacific to Hawaii in a similar fashion. Thrushes at large seem to have emerged sometime in the late Miocene epoch (most likely between 11.6 - 7.5 Ma) when they diverged from the Old World flycatchers and kin, Muscicapidae. This seems to imply that thrushes are ancestrally an Old World lineage and, if so, that they invaded the Americas on three separate occasions - the solitaires and bluebirds, Catharus and allies, and several species of Turdus and relatives. (And, further, that if the assumption about Neocossyphus crossing the Atlantic is correct, that the thrushes emerged in Afro-Eurasia, migrated to the Americas... and then migrated to Afro-Eurasia again.)

Relationships between the solitaires of Mexico, Central America, the Caribbean, and Hawaii - two interpretations. After Klicka et al. (2005).

From whichever stock they arose, the solitaires of Myadestes disseminated rapidly across the Americas, if genetic data is any indication. The various species of Myadestes diverged from one another perhaps as much as 7 Ma, not very long after the origin of Turdidae itself. The Hawaiian solitaires in particular seem to be closest to the Mesoamerican and Caribbean species, and very possibly are closest to the brown-backed solitaire (M. occidentalis). They dispersed to the Hawaiian islands, apparently by wing, at least 4 Ma. Although no phylogenetic study has been made of these five Hawaiian species together, their broad similarities and the difficulty of transit between Mexico and Hawaii for medium-sized passerines like these probably means that they are one another's closest relatives and arrived as the result of a single dispersal event. Today, three of these species are probably extinct, but all of them persisted into the historical era, leaving behind enough information to draw some conclusions about the whole group.

The first of Hawaii's solitaires to vanish from the islands was a cryptic bird known as the 'āmaui, a shortening of the Hawaiian manu a Māui, "bird of Māui", after a Hawaiian folk hero. In fact, all the thrushes which ranged onto Oahu, Maui, Moloka'i, and Lāna'i (those latter three originally one island, 'Maui Nui', which was partially submerged in recent geological history) were originally known by this same name, but only this bird, M. woahensis, seems to have retained it. Known only from a single holotype, collected by Andrew Bloxam in 1825, as well as some subfossilized bones, what little we know about this species is owed to guesswork based on other solitaires. Abundant in the early 19th Century, it vanished without trace or record by about 1860, thus marking the disappearance of Myadestes from the island of Oahu.

The remaining species have had the fortune to persist for much longer, with two vanishing late in the 20th Century and two more remaining extant to the present day. Each of these shares a common predilection for fruit, feasting occasionally on insects instead during the breeding season, and can be recognized by their calls, which are said to resemble a policeman's whistle. The oloma'o (M. lanaiensis) of Maui, Moloka'i, and Lāna'i, though still officially listed as Critically Endangered, was last definitively spotted in 1980 and is feared to be extinct. A reclusive bird, it was often seen to sit motionless, hunched in the underbrush in between bursts of song.

Illustration of the kāma'o (Myadestes myadestinus) by Frederick William Frohawk from between 1890 and 1899. Retrieved via Wikimedia Commons.

The kāma'o (M. myadestinus) similarly disappeared during the course of the 1980s, last being seen in the Alaka'i Swamp in 1989. The largest of the Hawaiian solitaires at 20 cm (7.8 inches) in length, it was endemic to the island of Kaua'i. It was noted for its habit of suddenly bursting into the air from the underbrush and singing a few notes, and then falling back into cover, a behavior unknown in other solitaires. As early as the 1960s the kāma'o had become very uncommon, retreating into higher altitudes, and was often seen with lesions around its mouth and feet. These are a telltale sign of avian malaria, introduced by mosquitoes breeding in the sties of invasive pigs. This disease must have devastated the kāma'o's population, and has taken its toll on countless other endemic bird species as well. Alaka'i was hit by a succession of hurricanes in the 1980s and 1990s which must have had a terrible effect on the small range of these birds, With no sightings in the last 25 years, even in the face of detailed surveys of Alaka'i and its avian life, it has to be assumed that the kāma'o is extinct.

Puaiohi (Myadestes palmeri). Taken by Eike Wulfmayer at an avian conservation center in Volcano, HI, 2002. Retrieved via Wikimedia Commons.

Another Kaua'i solitaire, however, has happily avoided the kāma'o's fate. The puaiohi (M. palmeri) currently resides in craggy areas above 1,000 meters or so in altitude (3,280 feet) in Alaka'i Wilderness Preserve, in the same area as the kāma'o's last haunts. Unlike its only living relative amongst the Hawaiian solitaires, the 'ōma'o, the puaiohi typically nests in cliff faces. This is a bit odd for a thrush, since most species prefer to nest in branches, cavities, or in a few cases, on the ground. Its particular environmental needs doubtless put additional pressure on this species, which seems to number at most at only 200 individuals in the wild.

'Ōma'o (Myadestes obscurus) as portrayed by Joseph Smit, 1869. Retrieved via Wikimedia Commons.

The 'ōma'o (M. obscurus) of the big island, Hawai'i, seems to be doing somewhat better, with perhaps as many as 200,000 individuals living in the wild on the eastern and southern slopes of Mauna Kea. Efforts to maintain its shrinking habitat on the island are underway in the form of aggressive reduction of the range of feral pigs and other invasive mammals. The puaiohi is under the careful watch of conservationists as well, with captive breeding programs seeing considerable success in reintroducing birds to the wild. The future is brighter for these two birds than for their vanished kin, but introduced mammals which predate upon the solitaires, invasive birds like laughingthrushes which compete with them for food and space, and foreign plants which threaten to reshape what little habitat they have left, continue to endanger the 'ōma'o and puaiohi. In addition, climatic events such as El Niño imperil the species by shortening their breeding seasons with the droughts they often bring to the islands. As we enter another El Niño period in early 2016, it can only be hoped that man-made climate change doesn't doom this unique lineage of thrushes to permanent extinction like the Hawaiian honeyeaters before them.

For another extinct island-endemic bird:

• Red Rail

Sources:

• BirdLife International (2016) Species factsheet: Myadestes lanaiensis. Downloaded from BirdLife on 25/01/2016.
• BirdLife International (2016) Species factsheet: Myadestes myadestinus. Downloaded from BirdLife on 25/01/2016.
• BirdLife International (2016) Species factsheet: Myadestes obscurus. Downloaded from BirdLife on 24/01/2016.
• BirdLife International (2016) Species factsheet: Myadestes palmeri. Downloaded from BirdLife on 25/01/2016.
• BirdLife International (2016) Species factsheet: Myadestes woahensis. Downloaded from BirdLife on 24/01/2016.
• Klicka, John, Gary Voelker, and Garth M. Spellman. "A molecular analysis of the 'true thrushes' (Aves: Turdidae)." Molecular Phylogenetics and Evolution 34. 2005.
• Miller, Matthew J., Eldredge Bermingham, and Robert E. Ricklefs. "Historical biogeography of the New World solitaires (Myadestes spp)." The Auk 124. 2007.
• United States Fish and Wildlife Service: "Draft Revised Recovery Plan For Hawaiian Forest Birds." 2003.

I suppose some introductions are in order?

Male Andean condor (Vultur gryphus) photographed at the Cincinnati Zoo by Greg Hume. Retrieved via Wikimedia Commons.

Normally hitting a champagne bottle against the hull is customary for a christening - but since this is a blog and not a boat, this crummy post will just need to do the job! My name is Val. I'm a college student from the American Midwest, where I previously studied evolution and ecology (for about two semesters...) and am now studying sociology. Despite the change in major, zoology and palaeontology have been, and remain, a favorite hobby and area of personal study for me. For the past two years I've been running a blog under this same name on Tumblr. This has been a rewarding experience for me, but sometimes going a bit more in-depth is necessary, something for which Tumblr's particular format is not especially well-equipped.

Accordingly, I've decided to launch this Blogspot site as a companion to the Archosaurophilia Tumblr blog, As this blog goes forward, I hope to catalog my continued attempts to learn more about that most wondrous group of amniotes, the archosaurs, and to share what I learn through a series of posts cataloging archosaurian evolution, behavior, history, and conservation.

But what are archosaurs, any way?

Archosauria is a clade (that is, a natural, evolutionary group of organisms) made up of crocodilians, modern birds, their last common ancestor, and all descendants of that ancestor. This branching category, centered on that single, ancestral node, encompasses a number of widely successful animal groups - including extinct dinosaurs, pterosaurs, and relatives of crocodilians - which flourished during the Mesozoic Era (approx. 252 to 66 Ma) and have continued to do so through our own Cenozoic (66 Ma to present). By most traditional reckonings, Archosauria’s definition would qualify it as a subset of Reptilia, but the inclusion of birds makes traditional, Linnaean taxonomy a bit problematic. The hierarchical rankings Linnaeus created in the 18th Century have been forced to adapt, as evolutionary science and palaeontology have painted a complex picture of the history of life and uncovered a theretofore unimagined diversity of animals which don’t fit into neatly-arranged Classes and Orders in an orderly and convenient way.

I hope to do this diversity justice over the coming months, and I hope that whoever chooses to stop by and read the articles enjoys it as well. Bonsoir!

Red Rail (Aphanapteryx bonasia) - A Lost Rail From Mauritius

Above: a plate by Frederick William Frohawk (1861 - 1946), wildlife artist; retrieved via Wikimedia Commons. Below: sketch of a hunted specimen ca. 1601, attributed to one Joris Joostensz Laerle; retrieved via Wikimedia Commons.

Modified from the original posted on the Archosaurophilia Tumblr on January 1, 2016.

The red rail (Aphanapteryx bonasia) was the largest of Mauritius’ rails and certainly the strangest in appearance. Similarly to the dodo and many other birds native to the Mascarene islands, it was completely flightless, and its small wings would have been concealed in life beneath its shaggy, reddish-brown plumage. The only physical remains known from this species are its pelvis and leg bones, which makes it difficult to gauge its full size in life, but contemporary accounts compare it in size to a large hen. Within the rail family, its closest relative seems to be the Rodrigues rail (Erythromachus leguati), also extinct. More distantly, it is allied with the white-throated rail (Dryolimnas cuvieri) of Madagascar, the Seychelles, and Comoros, which today appears to be the only endemic flightless bird remaining on the Indian Ocean’s islands.

Its slender, vaguely ibis-like bill suggests a cursorial foraging lifestyle, preying on small invertebrates. The now-extinct land snail Tropidophora carinata, also endemic to Mauritius, appears to have been one such prey item, as some subfossilized shells belonging to this species carry blunt damage marks consistent with this bird’s beak.

Sadly, very little is known for sure about the red rail, since like many other flightless birds of the world’s oceanic islands, it became extinct a short time after humans colonized its home. The tropical forests of Mauritius began to shrink after the island was claimed by the Dutch East India Company in the 17th Century, spelling doom for this rail, the dodo, and many others, as overhunting and deforestation disrupted their habitat. By 1700, the Red rail had disappeared forever.

Puzzling over this flightless rail and the dodo, centuries before Darwin’s On the Origin of Species, English adventurer Peter Mundy observed:

“Of these 2 sorts off fowl afforementionede, For oughtt wee yett know, Not any to bee Found out of this Iland, which lyeth aboutt 100 leagues From St. Lawrence. A question may bee demaunded how they should bee here and Not elcewhere, beeing soe Farer From other land and can Neither fly or swymme; whither by Mixture off kindes producing straunge and Monstrous formes, or the Nature of the Climate, ayer and earth in alltring the First shapes in long tyme, or how.”

Coloborhynchus - The Maimed Beak

Coloborhynchus piscator by John Conway. Retrieved via Wikimedia Commons.

Modified from the original posted on the Archosaurophilia Tumblr on July 1, 2015.

Coloborhynchus (”maimed beak”) was an ornithocheirid pterosaur that lived during the Albian age of the Cretaceous Period (approx. 98 Ma). Although at one time or another as many as eight species have been assigned to this genus, many are considered of dubious taxonomic validity, and others (such as Uktenadactylus wadleighi) have been split off into other genera. This may mean that as little as only a single species, the type (C. clavirostris [Owen, 1874]), actually belongs to the genus.

To further complicate matters, some experts have suggested an affinity with the Moroccan pterosaur Siroccopteryx, although that genus was described as an anhanguerid. (The taxonomic row over Anhangueridae and Ornithocheiridae is perhaps better glossed over for now.)

The fossil material for which it was named was found in the UK in the 19th Century, the primary element of which is a weathered jaw tip (hence the genus’ name).

Like other ornithocheirids, Coloborhynchus was probably well-suited not only for flight over marine habitats, but bobbing or even swimming in the sea as well. Its diet probably consisted primarily of fish.

Further Reading

Imperial Woodpecker (Campephilus imperialis) - A Forgotten Giant

Video clip from the Macaulay Library, Cornell Lab of Ornithology.

Modified from the original posted on the Archosaurophilia Tumblr on April 9, 2015.

Although the sad tale of its cousin the Ivory-billed Woodpecker is well-known, the existence of another giant woodpecker which once resided on the same continent, spanning the Sierra Madre ranges of Mexico, is less well remembered. The Imperial Woodpecker (Campephilus imperialis) is, or at least was, the largest woodpecker in the world, a huge and stately bird of the mountains with a prominent crest. Habitat degradation of the forests in which it lived doomed this uncommon species to decline, and ultimately to disappear entirely. The dangerous situation involving cartel violence in the parts of that country which the woodpecker called home have prevented any large-scale investigations into its last haunts, leaving the possibility of its extinction ultimately a mystery.

The footage here was filmed by a Dr. William Rhein in Durango in 1956, and represents the last documented sighting of this species, and the only footage or photographic evidence. It shows a female crawling slowly up the trunk of a pine tree before flying away, never to be seen again.

House Sparrow (Passer domesticus) - The Globetrotter

"Wróbel zwyczajny - Passer domesticus - samiec", a house sparrow in Poland, taken by Alina Zienowicz. Retrieved via Wikimedia Commons.

Modified from the original posted on the Archosaurophilia Tumblr on November 21, 2014.

The house sparrow (Passer domesticus) is a ubiquitous passerid Old World sparrow, native to Eurasia and North Africa, but also found in introduced populations across three other continents, including the Americas, Sub-Saharan Africa, and Australasia. It owes its phenomenal success in part to its ability to adapt to areas of human habitation in wildly varying habitats and climate zones. The house sparrow was among the first species granted a binomial name by Carl Linnaeus, owing to its ubiquity in the European gardens which that scholar so often saw, and it is consequently sometimes treated as the archetypical bird (and perhaps, by extension, the archetypical dinosaur).

House sparrows will feed happily on seeds and grains from plants such as corn or wheat, as well as wild grasses and feed left out by humans. They will also hunt insects on occasion. They can be seen hopping around in gardens, on trees, or on rooftops in inhabited areas, almost never occurring in the wilderness in their introduced range. They commonly congregate in flocks in which males keep a firm hierarchy over the female birds through the winter and fall months, but it is more poorly crystallized in the spring and summer when the females seem to be more assertive. They are naked and helpless upon hatching from a clutch of anywhere between one and eight eggs, and will live for as much as almost sixteen years.

Due to their cosmopolitan distribution and adaptability, the House sparrow is ranked as a Least Concern species by the IUCN, though sub-populations in certain areas, such as the Indian subcontinent, are threatened.

Demoiselle Crane (Anthropoides virgo) - The Little Goliath

"Demoiselle Cranes at Tal Chappar" by Sumeet Moghe, taken on February 1, 2014. Retrieved via Wikimedia Commons.

Modified from the original posted on the Archosaurophilia Tumblr on October 5, 2014.

Demoiselle cranes (Anthropoides virgo) are avian migrants par excellence. The smallest crane in the world, standing at a mere 76 cm (30 inches), the Demoiselle still achieves the most goliath task in the avian world every year. In August and September, tens of thousands of the birds take wing to avoid the icy winters of Central Asia, passing over the Himalayas on their way to the warmer climes of India. The way is arduous, with intense attrition rates from inclement weather and predation by eagles. All the same, they are resilient fliers, capable of traveling hundreds or thousands of miles without needing to land or to eat, and most of the birds surmount this monumental obstacle for years on end.

While some western populations winter in northern Africa instead, it is in India that the demoiselle is best known. In fact, the people of Rajasthan, who call the Demoiselle the koonj, revere the crane for its historic place in Indian literature and mythology. Demoiselles typically mate for life in monogamous pairs, and care for hatchlings for about two months until they fledge. Unlike most cranes, the demoiselle is not a bird of the wetlands, instead preferring upland regions, where it feeds upon a wide array of both plant and animal matter.

The Curious Case of Crurotarsi

Redondasaurus at the Carnegie Museum, Pittsburgh, by the author

Modified from the original posted on the Archosaurophilia Tumblr on August 29, 2014.

Rutiodon validus by Dmitry Bogdanov. Retrieved via Wikimedia Commons.

You’ll see them in countless dinosaur books—at least for a page or two. Pseudo-crocodilian shapes undulating through the waters of some Triassic swampland; reptilian eyes glaring balefully at some scampering segisaur or lumbering aetosaur; sometimes opening its maw to show off a dazzling array of fangs—only to slip beneath the water and off the page, exiting stage-right for the dinosaurs evidently destined to take up the rest of the book. The phytosaurs are animals seen rather than heard in these Triassic dioramas, but in the actual science of vertebrate palaeontology, they are a bit better appreciated. Found on five continents (six if you consider that India was still separate from Asia at the time), phytosaur elements are common in almost all Triassic strata, and so are useful in the craft of biozonation. What this means is that phytosaur elements are so ubiquitous and distinctive throughout the four land vertebrate ages (LVAs) of the Late Triassic, that they can be used to determine the age of particular rocks. This is likely due to their preference for the sort of wet, lowland habitats so conducive to fossil formation.

Mystriosuchus by S.W. Williston, 1914. In the public domain.

Phytosaurs have been known to science for almost two-hundred years, the first known specimen having been described by a scientist named Jaeger in 1828, in the form of some fragmentary skull and mandibular elements. This he named “Phytosaurus cylindricodon”, the ‘cylindrically-toothed plant lizard’. This rather unfortunate name springs from the presence of mud fillings in the jaws of the animal which Jaeger mistook for the teeth of an herbivore. This mistake was eventually addressed, and the fragmentary nature of this original specimen has led to “Phytosaurus” being considered an invalid taxon. Nonetheless, the name has stuck, and Phytosauria has thence been used most commonly to describe these Triassic animals.* This name was eventually contested by the inimitable Thomas Huxley in 1875, who coined 'Parasuchia’ for this group. Meaning 'parallel to crocodiles’, this more accurately reflects these animals for their general resemblance to modern crocodilians. But it also reflects the close relationship then imagined to exist between phytosaurs and crocodiles, an issue which (in the roundabout sort of way in which I’ve gotten to it) is at the crux (or crus?) of this post.

Once more complete specimens than Jaeger’s began to emerge and provide a fuller image of what the phytosaurs were, the similarities to modern crocodilians were striking. These were semi-aquatic predators of a similar nature to those modern-day archosaurs, low-slung and long-snouted. They came, broadly, in three morphological 'types’ that (though they don’t appear to correlate in any meaningful way to the group’s internal classification) show us the wide variety of lifestyles these animals practiced during their Triassic reign: “high-snouted” altirostral phytosaurs, generalists of a kind not unlike alligatorids today; “short-snouted” brachyrostral phytosaurs, with massive heads that must have made quick work of small tetrapod prey; and “long-snouted” dolichorostral phytosaurs, piscivores that eerily recall the modern gharial. The dorsal scutes sheathing their backs and their probable lifestyle seem perfectly 'parasuchian’, but in other ways they greatly diverged from crocodiles. Phytosaur nostrils were placed above the eyes, rather than at the tip of the snout; their tails were held off of the ground in a semi-erect posture, rather than dragging as those of crocodilians do; and, most damningly, their ankles were far more primitive in structure than those of any archosaur.

Smilosuchus by Nobu Tamura. Retrieved via Wikimedia Commons.

Despite these important details, phytosaurs were long placed deep within Archosauria as a sister taxa to Suchia, in what would traditionally have been called Pseudosuchia, the crocodile-line archosaurs. However, by the late 20th Century, 'Pseudosuchia’ carried outdated connotations from the days of Owen, originally having been applied to a vast, paraphyletic smattering of “almost-crocodiles”, or “thecodonts” from the Triassic. Thus, in 1990, Sereno and Arcucci erected Crurotarsi—from crus and tarsus, relating to the articulation of the leg bones—based off of a subtly different definition from Pseudosuchia: the last common ancestor of the phytosaurs and the modern crocodiles, and all of its descendants. This neatly applied the Crurotarsi label to roughly the same group, and all was well for a couple of decades. Ultimately, it would be Sterling J. Nesbitt’s sweeping 2011 reassessment of archosaurian cladistics that changed the situation—based on the uniquely phytosaurian features mentioned in the last paragraph, Nesbitt found that phytosaurs were no closer to crocodilians than they were to birds, and instead evolved before the bird-croc split—and thus before the emergence of the crown-archosaurs. Pinned by its definition on phytosaurs as it was, this dragged Crurotarsi along with the phytosaurs to include them, as well as the entirety of Archosauria! This rather dramatic change has had its detractors, but for now Pseudosuchia has resumed its place at the helm of the croc-line archosaurs—it is a pretty lousy name, I agree, but it’s just the way of the business.

So is there really a magical, important distinction between the crown-group and the rest, when a whole group could easily belong on either side of the divide? Should an archosaur blog restrict itself to the croc-bird node? Are phytosaurs “archosaurish” enough?

Well… they’re definitely crurotarsans.

* Reports of phytosaurs from the earliest Jurassic of Morocco have, thus far, proved unfounded, but it remains possible that they lived past the T-J boundary.

Kagu (Rhynochetos jubatus) - New Caledonia's Avian Mystery

Taken at the Walsrode Bird Park, Germany, by Wikimedia Commons user Quartl.

Modified from the original posted on the Archosaurophilia Tumblr on August 7, 2014.

The Kagu (Rhynochetos jubatus) is a curious bird native to the montane forests of the the island of New Caledonia, a French overseas collectivity in the southwest Pacific Ocean. Its placement among the avian family tree has been complicated since the time of its discovery. Once thought to be an ardeid like egrets and herons, it was considered in more recent times to be a gruiform. Of late, it's usually been allied to the sunbittern of Central and South America, suggesting that the two species may be part of an ancient bird lineage distantly related to the tropicbirds (Phaethontiformes).

It's average-sized so far as ground-dwelling birds go, averaging at around 55 cm long. Strictly carnivorous, its diet consists mostly of invertebrates and small reptiles from the forest floor. Its generic name ('rhyno' = nose and 'chetos' = corn) stems from the 'nasal corns', a pair of flaps over the nostrils unique to the Kagu among all birds. It is the heraldic bird of New Caledonia, and despite pressure from introduced mammals which has reduced its range on the island, it is the focus of a number of dedicated conservation efforts which have seen considerable success.

The 'Duckbill' Stomp

By the late Zdenek Burian. In the public domain - I think?

Modified from the original posted on the Archosaurophilia Tumblr on July 15, 2014.

Nothing tickles me more when I leaf through old dinosaur books than wimpy, gangly hadrosaurs baring their necks for a tyrannosaur's waiting jaws, seemingly without a fight. I guess it's easy to mistake them for easy prey, being that they generally lack obvious weapons of self-defense, like the flashy horns, armor, or spikes of some of their fellow ornithischians. The fact that size in and of itself can be a means of defense seems to be ill-appreciated. The largest of hadrosaurs were beefy creatures indeed - for example, Shantungosaurus from the Campanian of China, which measured up to as much as 16.6 meters in length (54 feet), larger than any theropod and doubtlessly much heavier.

Figure from the Magnapaulia description paper, Prieto-Márquez et al. (2012). Retrieved via Wikimedia Commons.

Magnapaulia laticaudus (née "Lambeosaurus" laticaudus) is another such colossal hadrosaur (though if we use D&D's metric, it's more accurately Gargantuan) from the Campanian of northern Mexico, around 73 Ma. Its most unique physical feature was surely its unusually deep tail profile, lending to its image as that of a very impressive animal indeed—it measured in somewhere between 12.5 and 16.5 meters in length (41 to 54 feet) and may have weighed in excess of 20 metric tons (22 short tons). Size alone would have been an adequate defense for something like Magnapaulia—given the opportunity, it could well have just trampled a large theropod to death. It also seems to have sported a series of large, irregular scales which may represent some kind of osteoderms, offering it a thick hide as well.

Magnapaulia's sister taxon Velafrons and an indeterminate saurolophine from the same general region also represent atypically large hadrosaurs, but the reason for this abnormal size is, as of yet, unclear. Whatever the case, far from being a land of noodly, amphibious 'duck-bills', the Baja in the Upper Cretaceous must have been a tyrannosaur's nightmare.

"Edmontosaurus pounding Albertosaurus" by Durbed. Retrieved via Wikimedia Commons.