I Know Dino Podcast Present Notes: Microraptor (Episode 69)

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Episode 69 is all about Microraptor, a crow-sized dinosaur with 4 wings.

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On this episode, we talk about:

The dinosaur of the day: Microraptor

Microraptor means “small thief”

Lived within the Cretaceous, and fossils present in Liaoning, China

Three speices: Microraptor zhaoianus, Microraptor gui, Microraptor hanqingi
Some scientists suppose they’re all one species, Microraptor zhaoianus

Synonym for Microraptor: Cryptovolans, one other four-winged dinosaur
Named Bb Xu Xing et al‭ ‬in‭ ‬2000.
Microraptor‘s naming was controversial, when it was revealed the primary specimen described was truly tail of a Microraptor, higher physique of Yanornis and a 3rd species that was put collectively in China and smuggled into the US on the market. When Xu Xing from Beijing’s Institute of Vertebrate Paleontology and Paleoanthropology revealed it was a forgery, Storrs Olson, the chook curator on the Nationwide Museum of Pure Historical past Smithsonian, wrote an outline of the tail, naming it Archaeoraptor liaoningensis. Later, Xu Xing discovered the remainder of Microraptor (to go along with the tail, which was Microraptor) and officialy described it with the identify Microraptor zhaoianus

For the reason that identify Archaeoraptor liaoningensis and Microraptor zhaoianus confer with the identical specimen, usually Microraptor zhaoianus could be a junior synonym of Archaeoraptor, because it was formally named afterwards.
Archaeoraptor was revealed to be pretend earlier than it was formally named. Olson tried to assign the identify Archaeoraptor liaoningensis to the tail a part of Microraptor to take away the taint

Archaeoraptor was named (tail) as a lectotype, a reputation from a bunch of specimens with the identical identify. However since Archaeoraptor wasn’t formally named, (solely within the media, not within the scientific world), the identify didn’t depend, and is why the identify Microraptor prevailed

In December 2015, U.S. Immigration and Customs Enforcement officers mentioned they had been returning a Microraptor fossil to China
Cryptovolans pauli (named means “hidden flying” and species identify honors Gregory S. Paul, was described in 2002. Additionally present in Liaoning, China, lived concurrently Microraptor. The scientists who described Cryptovolans thought it was a chook as a result of it had major feathers, which had been on the arm and leg. Later research discovered that it was similar to Microraptor (had an extended tail, however had different options in widespread). In 2004, Phil Senter and colleagues prompt Cryptovolans pauli and Microraptor gui had been junior synonyms of Microraptor zhaoianus. Different scientists have supported this.
Stephen Czerkas mentioned, when describing Cryptovolans, that Microraptor might have been a greater flier than Archaeopteryx, and that Dromaeosauridae could also be a basal chook group and that basal dromaeosaurs had been small, lived in bushes, and will a minimum of glide (later discoveries of extra primitive dromaeosaurids with quick forelimbs meant they couldn’t all glide)

Over 300 specimens of Microraptor have been discovered (very plentiful of their ecosystem)
Much like Sinovenator, a basal troodontid, most likely as a result of they’re each primitive members of two teams which might be carefully associated, and are near the cut up between dromaeosaurids and troodontids

Small, had 4 wings

Crow-sized

Grownup Microraptor was 1.4-2.7 ft (42-83 cm) lengthy and weighed as much as 2.2 lb (1 kg)
In 2012, Benson estimated it was 3.9 ft (1.2 m) lengthy

One of many smallest non-avian dinosaurs, that we all know of
First non-avian dinosaurs discovered with impressions of feathers and wings
Exhibits the evolution between birds and dinosaurs

Physique coated in feathers, with a diamond-shaped fan on the tip of the tail
Had lengthy feathers on arms, tail, and legs. In 2003 Xu Xing described the primary Microraptor specimen as having 4 wings and mentioned it might have been capable of glide. There’s been debate over whether or not or not it Microraptor may additionally fly.

Had lengthy flight feathers on legs in addition to wings (one of many few dinosaurs recognized to have this)

Had 4 wings, one every forelimb and hindlimb

Had major (feathers on the hand and foot) and secondary (feathers on the arm and legs)
In 1915, William Beebe mentioned that birds might have had 4 wings in some unspecified time in the future.

At first scientists thought Microraptor saved its legs and arms stage when flying, or they overlapped one another, however in 2005 Sankar Chattererjee mentioned this was not doable and as a substitute the legs had been on a distinct stage however parallel to the arms, in order that from the entrance it appeared prefer it had two pairs of wings
Sankar Chatterjee mentioned in 2005 that as a way to glide, Microraptor launched from a perch, swooped down right into a U-shaped curve after which lifted once more, touchdown on one other tree. Utilizing laptop algorithms, Sankar additionally discovered that Microraptor would have been capable of fly a minimum of every so often, along with gliding
Not all scientists agree with this technique (known as “biplane” technique); Microraptor might had had a number of methods of gliding or flying

Unclear whether or not Microraptor held its legs instantly underneath its physique, or if its legs had been splayed to the facet when within the air. Understanding this can assist scientists perceive the way it flew/glided, however usually its hips and higher leg fossils are discovered crushed, so arduous to say

In 2013, researchers from the College of Southampton created a Microraptor mannequin to experiment positions it held inside a wind tunnel. They discovered that it labored greatest “when the limbs had been within the straight-down poster…[and the] tail operated as a lift-generating construction”
For the wind tunnel research, scientists made a poseable scale mannequin of Microraptor, with feathers from geese and pigeons

Examined Microraptor with sprawling limbs, limbs projecting downwards, and with out hindlimbs
From the Scientific American weblog publish that described the experiment in 2013: “The tail operated as a lift-generating construction, that means that Microraptor can precisely be described as a five-winged flier, not only a four-winged one.”
They discovered it may glide simply however flying would have been troublesome (an excessive amount of drag)

In line with the publish, “It was effectively capable of glide it doesn’t matter what the feather or wing configuration: the truth is, we concluded that each one Microraptor wanted as a way to glide successfully was a flat wing floor – feather asymmetry, anatomy and configuration didn’t make that a lot distinction (Dyke et al. 2013), a discovery which helps the view that the evolution of theropod wing and feather anatomy didn’t happen inside an aerodynamic context.”
So most likely solely generally glided, didn’t specialise in it

Not all scientists suppose Microraptor may have flown or glided. Some research discovered it’s shoulder socket confronted downward and backward, which meant it couldn’t elevate it’s arm vertically and flap. Some scientists mentioned that the shoulder girdle is curved so the ought to joing it excessive on the again, permitting Microraptor to boost its arms vertically

In 2013 Dyke and others carried out wind experiments that confirmed Microraptor may glide between low elevations.

The lengthy wing feathers on Microraptor‘s arms would even have made it arduous for Microraptor to run or transfer on the bottom, as a result of they might have dragged on the bottom. And its feathers would have dragged when its arms had been in a impartial place, so Microraptor couldn’t use its clawed forelimbs to go after prey or transfer objects, with out damaging its wings
Couldn’t take off from the bottom, since it will have broken the flight feathers on its ft

Some scientists suppose the feathers on its ft would have made it troublesome for Microraptor to run. As a substitute, it lived in bushes and doubtless glided
Analysis in 2012 discovered that Microraptor had nice management over its hind wings (helped enhance “its price of flip by 33 to 50 %, in comparison with utilizing solely the entrance wings,” in accordance with Michael Habib from the College of Southern California, who co-presented analysis over Microraptor‘s motion on the Society of Vertebrate Paleontology in 2012
Hind wings might have created drag, more durable to fly or glide.

Microraptor‘s tail feathers, which had been like a fan, would assist right the hind wings’ pitch, in order that it will not nostril dive within the air
Unsure if Microraptor was arboreal or terrestrial, however it spent a minimum of a while in bushes

Utilizing hind wings to extend turning pace might give some perception into fashionable birds that hunt, like eagles

Not sufficient fossilized feathers discovered to show how dinosaurs developed into birds, however Microraptor helps to fill a spot

Not all scientists are satisfied of the research. Some say that it solely appears at how a hindlimb impacts an animal that glides, not animals that flap their wings. And gliding is just not essentially a part of the evolution of flight
Debate over the evolution of flight. Was it the bottom up (quick runners turned airborne) or tree down (arboreal animals that might glide changed into fliers)
Archaeopteryx solely had one set of wings on entrance limbs; Microraptor was first to have wings on entrance and rear limbs

Microraptor lived 20-25 million years after Archaeopteryx, which exhibits that flight began evolving greater than as soon as within the Mesozoic (although just one lineage continues to be round)
Due to lengthy leg feathers discovered on Microraptor, in addition to different raptors and Archaeopteryx, birds might have developed from having 4 wings to having two entrance wings
As a result of Microraptor is in the identical household as Velociraptor and Deinonychus, which lived later (dromaeosaurs), these raptors had been most likely secondarily flightless. Meaning they developed from flying ancestors. Not everybody believes this although, and a few suppose Microraptor is distantly associated to different raptors

Had quick, downy tail feathers
Had some darkish and light-weight coloured feathers, some had been iridescent black, like a crow’s

In 2012 Quanguo Li and a staff analyzed Microraptor and discovered what colour it was. They examined melanosomes and in contrast them to fashionable birds. They discovered it was in line with birds with black, iridescent colours (shiny coat), which can have been used for speaking or for show

Predominantly iridescent feathers

One research discovered Microraptor might have flashed its tail feathers like a peacock
Tail most likely used for courtship

Tail most likely not useful for flight (not very aerodynamic)
Microraptor might have eaten lizards. In 2010 scientists discovered preserved intestine contents in a Microraptor zhaoianus, of mammal bones (doable cranium, limb, and an entire foot)
In 2011 scientists formally described a Microraptor with chook bones in its stomach, which appears to point out it swallowed an entire chook (one which perched in bushes, based mostly on its foot)

In 2013 scientists described fish scales discovered within the stomach of a Microraptor, which exhibits it was an “opportunistic feeder” and ate prey in arboreal and aquatic habitats
Unclear whether or not Microraptor scavenged or caught fish

Might have swooped down on the fish, however undecided

Had tooth most likely good for catching fish. Small tooth with a ahead angle (like a crocodile’s), serrated on one edge (so the fish wouldn’t be ripped aside whereas attempting to get away)
Microraptor‘s scleral ring in its eye made scientists suppose it hunted at night time, but when that’s the case it’s not clear why it had shiny, iridescent feathers
Lived in a forested, freshwater lake habitat

May additionally climb, and ate fish
Dromaeosaurids are carnivorous theropods carefully phylogenetically associated to Aves (a clade that features birds)

Most likely originated earlier than the Late Jurassic, however fossil document thus far is barely of Cretaceous

Lived all around the world, however there will not be that many fossils

Dromaeosaurids from the Late Cretaceous in North America have a poor fossil document, principally recognized from remoted tooth
In North America, solely 8 species named, based mostly on incomplete fossil stays

Also known as raptors (due to Jurassic Park)
Dromaeosaurids had S-curved necks, lengthy arms and enormous fingers with giant claws
Toes had a recurved claw on the second toe (sickle claw)

Claw might have been used for slashing, climbing, and even clawing via insect nests
A minimum of some might have lived in teams

Most, if not all, had feathers

Bipedal, however held their second toe off the bottom when strolling

Had lengthy tails, which will have been used to assist counterbalance when working or within the air
Typically small to medium sized (although Utahraptor was giant)

Some may fly or glide (like Changyuraptor yangi)
Very birdlike (habits and having feathers)
Enjoyable reality: Fukuivenator has listening to extra much like birds however what can birds hear? Not as huge of a spread as individuals. We will hear about 20Hz-20KHz, however birds (though there’s a honest quantity of variability) are extra within the few hundred Hz to 10KHz vary. Which is why “ultrasonic” repellers don’t work on birds, and doubtless wouldn’t work on dinosaurs both. Robert Dooling on the College of Maryland from the Middle for Comparative and Evolutionary Biology of Listening to defined that bigger animals have a tendency to listen to decrease frequencies, so dinosaurs might not have heard above 3KHz. So (with electronics a minimum of) people may talk with out dinosaurs listening to us…

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