#xenerodiops

Xenerodiops mycter was an unusual heron from the Oligocene (~30 million years ago) of what is now Egypt.

Known only from a partial skull and an arm bone, it's estimated to have stood around 70cm tall (~2'4") and was probably fairly similar in overall appearance to modern night herons. Its beak was powerfully built and had a distinctive downwards curve, shaped more like some types of stork than other herons – suggesting it may have had a convergently stork-like lifestyle, slowly walking through its marshy habitat probing around for prey and snapping up whatever its beak came into contact with.

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During the Late Eocene and Early Oligocene, the environment of Jebel Qatrani formation of Faiyum, Egypt was as lush as you could imagine, with tropical forests, and a vast system of wetlands, lakes and rivers connecting to the warm Tethys Sea. As you would expect, such a place was teeming with birds. The birds living here would have no idea that 30 million years later, the Sahara desert would bury all this greenery. But for now, it is an oasis where birds of a feather flock together.

Goliathia: One of the earliest known relatives of the shoebill, arguably one of the most awesome birds alive today.

Nycticorax: An early member of the modern night-heron genus. It is not named, but can be assigned to the genus thanks to the shape of its limb bones.

Xenerodiops: An early member of the stork family with a short, recurved beak. It probably fed like modern wood storks, probing the water with the beak open, snapping it shut on passing fish.

Nuphranassa: A member of the modern jacana group, but much larger than any living species at about the size of a chicken.

Janipes: Another large jacana. Not as large as Nuphranassa, but still larger than any modern jacana. One must wonder what these guys were walking on.

Palaeoephippiorhynchus: An early stork well known from this period. It closely resembles the saddle-billed and black-necked storks, but was markedly smaller in size.

By Ripley Cook

Etymology: The strangely appearing Heron

First Described By: Rasmussen et al., 1987

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Averaptora, Avialae, Euavialae, Avebrevicauda, Pygostaylia, Ornithothoraces, Euornithes, Ornithuromorpha, Ornithurae, Neornithes, Neognathae, Neoaves, Aequorlitornithes, Ardeae, Aequornithes, Pelecaniformes

Status: Extinct

Time and Place: Between 30.2 and 29.5 million years ago, in the Rupelian of the Oligocene 

Xenerodiops is known from the Jebel Qatrani Formation of Egypt 

Physical Description: Xenerodiops is a strange intermediate bird, slightly smaller than the smallest living stork - probably no longer than 70 centimeters or so. Still, it was larger than most living species of herons - so this wasn’t a small bird. It was fairly similar to storks too, in terms of the shapes of the known bones, so it seems likely that Xenerodiops was a precursor to that modern dinosaur group. It had a very strong, pointed bill, though, more like herons than storks - adapted for biting and even stabbing prey, rather than snapping up food trapped in vegetation. This weirdly short, heavy bill was also curved downwards, so different from living herons and somewhat similar to living storks. Its wings were heavy and robust, and in general, this was a very sturdy sort of bird. 

Diet: Xenerodiops probably fed on animals and, if it is a heron-stork like thing as supposed, it is logical to assume these animals were found in bodies of water.

Behavior: Without more fossils of Xenerodiops, it is difficult to piece together how it would have looked - especially without legs, which would point to whether or not this bird waded in the water as those birds it seems to be closely related to do. Still, for now, that is the simplest explanation for its general lifestyle. Its large beak would have been useful in reaching out into bodies of water and grabbing food sharply, possibly even stabbing it; being curved downwards, it could have been used similar to living stork bills in probing for food in the water. It is possible, then, that Xenerodiops did similar things, going into the water and grabbing as much food with its strong beak as possible, sensing food where it could not see. With its strong, robust wings, Xenerodiops would have been a powerful flier, able to gain a lot of movement from very few flaps of their wings. As with other dinosaurs, Xenerodiops would have probably taken care of its young; whether or not it did so in large colonies or in isolated nests is difficult to tell at this point. 

Creatures of the Jebel Qatrani by Stanton F. Fink, CC By-SA 2.5

Ecosystem: The Jebel Qatrani Formation is a fairly famous ecosystem from the Oligocene, a time when the weird creatures of the Eocene and Paleocene were beginning to transition into animals similar to those we see today. In addition to almost-modern forms, of course, there were also the fun offshoots, which is probably where Xenerodiops lies. Jebel Qatrani is famous for its transitional fossils, especially among mammals. It was a thick swamp ecosystem, extremely warm and wet - a tropical wetland, filled with animals taking advantage of the lush plantlife. This place was filled with a variety of mammals - dugong relatives like Eosiren, a transitional primate Aegyptopithecus, a weird pointy heavyset mammal Arsinoitherium, the slightly more hippo-esque but still weird Bothriogenys, giant hyraxes, the lemur-like Plesiopithecus, the false ungulate Herodotius, the strange carnivores Ptolemaia and Qarunavus, a marsupial Peratherium, hyaenodonts like Metapterodon, and an alarming number of rodents. Turtles and crocodilians and other reptiles were plentiful too, like the turtle Albertwoodemys, the crocodile Crocodylus megarhinus, a gharial Eogavialis, and the snake Pterosphenus. As for fish, there were a variety of tetras, snakeheads, and catfish.

Xenerodiops wasn’t the only dinosaur in this environment, either. Many other weird birds were found here, some just as odd and unplaceable as Xenerodiops. For example, Eremopezus lived here - it was some sort of large, flightless bird. Beyond that, we have no idea. There was also the (iconic and large) swimming flamingo, Palaelodus. An even larger sort of shoebill than the living one, Goliathia, prowled the swamps. A giant true stork, Palaeoephippiorhynchus, was a major fixture of the landscape. There were Jacanas like Nuphranassa and Janipes, turacos like Crinifer, and even birds of prey. In a lot of ways, therefore, the birds of the area were even weirder than the mammals - and Xenerodiops was just one of many. 

By José Carlos Cortés

Other: What exactly Xenerodiops is remains a mystery. Its weird combination of characteristics points to it being in the group of dinosaurs including a large number of living water birds - and both storks and herons. However, research has shown that storks and herons are actually somewhat removed from each other, with herons being more closely related to pelicans, shoebills, ibises, and even boobies than to storks. Is Xenerodiops, then, a weird, transitional, extinct member of this group of dinosaurs? Is it another evolutionary experiment altogether, with traits of many members of this group? Something else entirely? Only more fossils will help us to make the picture clearer. Some of these traits are shared in other weird waterbirds of the Paleogene (such as Mangystania), and it is entirely possible that there is an extinct clade of these animals, separate from all living members of the group.

~ By Meig Dickson

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