Saturday, December 9, 2017

The Avian Gizzard

The feeding of birds in winter is a favorite pastime of mine. It not only provides birds with the food they need to survive dangerously cold nights, it allows people like myself a convenient way to observe bird behavior at a relatively close range.

But I’m not the only one who appreciates these small winter gatherings. Sharp-shinned Hawks eagerly await the dawn arrival of finches, sparrows and doves to the feeding station, hoping to satisfy their own survival needs.

Accipiter Hawk
Photo Credit: Paul Cianfaglione
avianmusing.blogspot.com/
Even the glimpse of a distant accipiter can send feeder birds into turmoil, which sometimes ends with an individual striking a window or other object. When this happens, I tend to use the specimen as a learning tool, rather than burying it in a compost pile or throwing it back into the woods.

The Dark-eyed Junco (Junco hyemalis) I found resting near my homes foundation became the ideal specimen for dissection. It was a freshly dead bird, no decomposition whatsoever, which means it had to be opened up and examined immediately.

I removed feathers from the upper breast, lower breast and abdomen, pinned the wings to artist foamboard, then carefully sliced open the chest cavity. I cut away the large pectoral muscles from the sternum, lifted the sternum to reveal the innards.

Deceased Dark-eyed Junco
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/

Deceased Dark-eyed Junco
Photo Credit: Paul Cianfaglione
avianmusing.blogspot.com/
I separated a few of the organs to allow for pictures; these included the heart, liver, pancreas, duodenum and gizzard. Of all the organs, the gizzard, with its larger size and unique structure, drew most of my attention and then further study.  

Deceased Dark-eyed Junco
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
Pictured below is the juncos globular-shaped gizzard and part of the proventriculus.

Dark-eyed Junco Gizzard and Proventriculus
Photo Credit: Paul Cianfaglione
avianmusing.blogspot.com/
Birds have a much more complex and efficient stomach than their reptilian ancestors, but the avian stomach differs markedly in structure from the typical mammalian stomach. Birds have evolved a complex, two-part stomach that is a considerable improvement over the simple reptilian gizzard-like stomach. The first stomach area, the proventriculus, is a soft-walled glandular tube. The epithetlial cells of the gastric mucosa in the proventriculus secrete strong hydrochloric acids (pH 0.7 to 2.3), digestive peptic enzymes, and mucus and start the process of breaking down the structure of the food material. The food then passes to the second part of the stomach, the gizzard, a disk-shaped section posterior to the proventriculus with thick muscular walls and a hard, sandpaper-like inner surface. 

Avian Gizzard
Photo Credit: Paul Cianfaglione
Manual of Ornithology; Proctor
The gizzard performs the function of mammalian teeth, grinding and disassembling the food to allow the digestive enzymes a maximum of surface area to attack. In most birds the gizzard contains sand grains or small rocks to aid the grinding process. The gizzard is amazingly strong: it has been reported that the gizzard of turkeys can completely crush twenty-four walnuts (in the shell) in under four hours and turn surgical lancet blades into grit in less than sixteen hours (Streseman 1927-34). The gizzards of carnivorous birds can crush large bones, although most birds of prey regurgitate the bones, hair, scales and feathers of their prey in the form of pellets that are often found under or near their roosts (Source: Manual of Ornithology, Proctor N.S. 1993).

Avian digestive system
Image Credit: John Anderson; Ohio State University
http://avianmusing.blogspot.com/

After reading about the avian gizzard and taking a few close-up images, I decided to go a little further into my examination and cut directly into the organ. As it was just mentioned, the gizzard is amazingly strong, making it quite difficult to dissect, even with new scalpels

Once open, the gizzard revealed the juncos last meal of sunflower hearts, millet and husks. 

Dark-eyed Junco Gizzard
Photo Credit: Paul Cianfaglione
avianmusing.blogspot.com/
But not all birds need a powerful grinding gizzard, and birds that specialize in soft, easily digestible foods such as fruits and berries may have a gizzard that is substantially reduced in size and importance. Fruits and berries are rich in simple sugars, require little digestion, and pass rapidly through the avian alimentary canal. In fruit-eating euphonias, such as the Blue-hooded Euphonia, the gizzard may be reduced to a tiny nub of flesh on a stomach composed almost entirely of glandular proventriculus (Van Tyne and Berger 1959). 

Blue-hooded Euphonia Gizzard
Photo Credit: Paul Cianfaglione
From; Manual of Ornithology, Noble Proctor

Wednesday, December 6, 2017

A possible Lithornis vulturinus nodule from the London Clay Formation on the Isle of Sheppey, UK

It is extremely uncommon for a bird's fossilized bones to be preserved in its entire state, which makes it a challenge for any scientist to know exactly which species provided the skeleton. However, researchers can sometimes narrow down the identity of a potential candidate by comparing the bones of partial specimens to other well-known fossils, and of course extant birds.  

But when ancient birds are found fully articulated, or remarkably preserved in a three-dimensional form, interest in these fossils jump exponentially.

This was the case with Lithornis vulturinus (MGUH 26770), from the Lower Eocene of Denmark, which was initially described in 2005, and then more thoroughly examined in 2015.
Lithornis vulturinus MGUH 26770
Photo Property of Estelle Bourdon
http://avianmusing.blogspot.com/
Lithornis is a genus of extinct paleognathous birds; Paleocene-Eocene, 56–40 Ma. Lithornis were able to fly well, but are closely related to today's tinamous (which are poor flyers) and ratites (which are flightless birds) (Source: Wikipedia).

Knowledge of this astonishing fossil (MGUH 26770) was first brought to my attention two years ago, shortly after acquiring my own purported Lithornis fossil bird. No, this wasn’t a new and exceptionally well-preserved specimen, but a clay nodule of sorts, a rolled-up mass of bird bones.

Possible Lithornis vulturinus
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
Recovered from the London Clay Formation on the Isle of Sheppey, UK (Lower Eocene Epoch), this fossil nevertheless offered a number of details including a few complete bones. The London Clay, well known for its fossil content, is a stiff bluish clay which becomes brown when weathered.

Possible Lithornis vulturinus
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/

"Lithornis" is from ancient Greek for "stone bird", as it is one of the first fossil birds to become widely discussed. L. vulturinus was described as a vulture by Owen (1840) from the holotype fossil 955 738 - TM 024 717. The fossil was collected from Early Eocene London Clay deposits on the Isle of Sheppey, Kent, England by J. Hunter before 1793. This fossil was destroyed by bombing in World War II. Numerous isolated fossil bones of Lithornis vulturinus were incorrectly described anew, such as Parvigyps praecox and Promusophaga magnifica - the supposed earliest vulture and turaco, while others were referred to existing families of neognathous birds. A neotype (BMNH A 5204) was erected to replace the holotype in 1988 by Houde, who for the first time diagnosed it as a paleognath based on complete three-dimensional skulls and skeletons of congeners from North America. (Source: Wikipedia).

Lithornis vulturinus paleoart
Image credit: Wikipedia
http://avianmusing.blogspot.com/
In this post, I would like to present photos of my alleged Lithornis nodule, and go over some of the pertinent information presented in the 2015 paper, A redescription of Lithornis vulturinus (Aves, Palaeognathae) from the Early Eocene Fur Formation of Denmark (Bourdon, Lindow). It is with this detailed re-description that I hope to learn more about this recent acquisition.  

Let’s start with the abstract of the 2015 paper and part of the introduction, before moving into the gleaning process and comparative bone study. Please refer to Baumel and Witmer for further inquiries;


Abstract;

The extinct Lithornithidae include several genera and species of flying palaeognathous birds of controversial affinities known from the Early Paleogene of North America and Europe. An almost complete, articulated skeleton from the Early Eocene marine deposits of the Fur Formation (Denmark) was recently assigned to Lithornis vulturinus Owen, 1840. This study provides a detailed redescription and comparison of this three-dimensionally preserved specimen (MGUH 26770), which is one of the best-preserved representatives of the Lithornithidae yet known. We suggest that some new features might be diagnostic of Lithornis vulturinus, including a pterygoid fossa shallower than in other species of Lithornis and the presence of a small caudal process on the os palatinum. We propose that Lithornis nasi (Harrison, 1984) is a junior synonym of Lithornis vulturinus and we interpret minor differences in size and shape among the specimens as intraspecific variation. To date, Lithornis vulturinus is known with certainty from the latest Paleocene—earliest Eocene to Early Eocene of the North Sea Basin (Ølst, Fur and London Clay Formations). Among the four species of the genus Lithornis, the possibility that Lithornis plebius Houde, 1988 (Early Eocene of Wyoming) is conspecific with either Lithornis vulturinus or Lithornis promiscuus Houde, 1988 (Early Eocene of Wyoming) is discussed. The presence of closely related species of Lithornis on either side of the North Atlantic in the Early Eocene reflects the existence of a high-latitude land connection between Europe and North America at that time.

Introduction;

The extinct Lithornithidae are chicken-sized flying palaeognathous birds that were an important and diverse component of the Northern hemisphere avifaunas in the Paleocene and Eocene (60 to 48 million years ago). The only other flying palaeognaths are the Tinamidae (tinamous), which appear in the fossil record in the Early Miocene (Bertelli et al. 2014) and are represented today by 47 species inhabiting Central and South America (del Hoyo et al. 1992). The lithornithids had slender beaks equipped with foveae for sensory corpuscles that they probably used to probe along bodies of water (Houde 1988). Morphology of the wing bones, shoulder girdle and sternum suggest that lithornithids may have been better flyers than the Tinamidae (Houde 1988). The long hallux and curved claws of the lithornithids also suggest perching abilities (Houde 1988). Although Richard Owen described the first lithornithid species, Lithornis vulturinus Owen, 1840, in the nineteenth century (Owen 1840, 1841, 1846), Lithornithidae were not recognized as palaeognaths until the 1980s (Houde & Olson 1981; Houde 1986, 1988). Isolated bones of these enigmatic birds are superficially more similar to a number of neognaths than they are to any modern palaeognath group. Thus, their true identity has confounded taxonomists for over a century (Houde 1988).

As I mentioned earlier, the nodule held a number of bones, some of which I have tentatively identified as a partial humerus, pelvis, furcula, radius, highly degraded femur (?) and possible skull fragments. The more complete bones include one scapula, synsacrum and a cervical.

The paper describes the corpus scapulae as slender, poorly curved and narrow. In MGUH 26770, the acromion is remarkably elongated, with a pointed tip that projects cranially. The acromion is not preserved in the neotype of L. vulturinus. In MGUH 26770, the acromion shows a pneumatic foramen on its lateral face and a small tubercle on its dorsal face. The facies articularis humeralis is narrow and separated from the acromion by a deep notch. The prominent acromion is a salient characteristic of the Lithornithidae (Houde 1988).

Possible Lithornis vulturinus scapula
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
After reading this passage, I quickly realized that the scapula was not a complete bone, but missing most of the acromion as well as the facies articularis humeralis. However, the slender, poorly curved and narrow nature of the bone was still evident. The description also states that the length of the MGUH 26770 scapula as 67.0 mm, as opposed to my fossil, which at best measures 35.0 mm. Should I chalk this size discrepancy up as an example of intraspecific variation?

Oddly, the structural description of the scapula seems to contrast with the initial account of L. vulturinus below (MGUH 26770) in 2005;  


The glenoid facet of the proximal scapula is turned medially where it articulates with the coracoid (itself relatively narrow in MGUH 26770 and separated from the acromion by a deep notch). The blade of this element is markedly curved along its entire length and tapers to a point proximally, similar to some of the larger specimens described by Houde (1988); curvature of the scapula is not seen in smaller Lithornithidae, which have long, straight, and narrow blades.

The synsacrum is remarkably preserved in the clay nodule, and similarly described (below) in the 2015 paper. Photos in both the 2005 and 2015 research papers seem to support structural similarities with MGUH 26770.

The synsacrum is broken in its caudal end. It is not fused to the ilium (i.e. there is no sutura iliosynsacralis). The first vertebra synsacralis shows foveae costales. The synsacrum is narrow in its cranial part, and shows a prominent crista spinosa synsacri. Caudal to the three cranial most vertebrae synsacrales, the synsacrum widens considerably and the crista spinosa synsacri lowers and widens. Two rows of small foramina intertransversaria are preserved on either side of the synsacrum. No vertebrae caudales are preserved.

Possible Lithornis vulturinus synsacrum
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
Below is a description of the unusual two rows of small foramina intertransversaria in Baumel & Witmer. See my blogs listing of favorite sites for convenient access to Baumel & Witmer.   

Lamina transversa notarii/synsacri. During skeletal maturation the transverse processes of the notarial and synsacral vertebrae become coalesced, producing on each side a continuous transverse lamina. In mature birds the lateral border of each Lamina of the synsacrum becomes firmly ankylosed with the hip bone (as coxae) of its side. In instances where the fusion between the transverse processes is incomplete, the persistent windows are known as Fenestrae intertransversariae. The fenestrae as well as smaller foramina are traversed by nerves and vessels.

Do the windows (fenestrae) observed in my synsacrum indicate an immature bird?

Features of the pictured cervical; see Baumel & Witmer again for a detailed diagram.

Possible Lithornis vulturinus cervical
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
The zygapophyses of the vertebrae cervicales are slender and their facies articulares are longer than wide. Lacuna interzygapophysialis; Lacuna is the V-shaped or often broadly V-shaped indentation of the Lamina dorsalis of the vertebral arch, located between the right and left zygapophyses (Fig. 4.8C) at each end of a vertebra. Vertebrae from the cranial and intermediate series bear processus costales, which are elongated and spine-like in C4 to C11. The corpus vertebrae are bilaterally constricted in C4 to C12. The narrow corpus occurs in other lithornithid species (Houde 1988).

There also appears to be two sections of the cranium in the nodule. These sections include, in my opinion, the frontal and the parietal, with a clear sutura frontoparietalis visible.

Cranium. The cranium of MGUH 26770 is partially hidden by matrix, and is visible in occipital (Fig. 2), ventral (Fig. 3) and right lateral views (Fig. 4). Only the caudolateral part of the os frontale is visible. The sutura frontoparietalis and sutura laterosphenofrontalis remain completely open despite the specimen belongs to an adult individual, as in the neotype of Lithornis vulturinus (NHMUK A5204). The sutura frontoparietalis and sutura laterosphenofrontalis also remain open in adulthood in other lithornithids (Houde 1988) and tinamous (Elzanowski & Galton, 1991). (Source; A redescription of Lithornis vulturinus (Aves, Palaeognathae) from the Early Eocene Fur Formation of Denmark (Bourdon, Lindow).

Possible Lithornis vulturinus cranium
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
I also found a research paper called Cranial osteology in Tinamidae (Birds: Tinamiformes), with systematic considerations (Luís Fábio SilveiraI; Elizabeth Höfling II) in Portuguese. Though I was not able to translate the paper to English, the images provided were a tremendous help with comparative examples.




The remainder of bones in the nodule were unfortunately too incomplete, and lacking key features, for further scrutiny.

Prior to the acquisition, it was mentioned that the fossil bird may be a member of the extinct Lithornithidea.

How they (paleontologist/collector) came to that conclusion, I believe, would be through the identification of the skull fragments and synsacrum. If that’s the case, I concur.

Lastly, I would like to go back and offer a brief parting thought about the woodcut of the L. vulturinus holotype.  
Woodcut of the L. vulturinus holotype
Image credit: Wikipedia
http://avianmusing.blogspot.com/
L. vulturinus was described as a vulture by Owen (1840) from the holotype fossil 955 738 - TM 024 717. The fossil was collected from Early Eocene London Clay deposits on the Isle of Sheppey, Kent, England by J. Hunter before 1793. This fossil was destroyed by bombing in World War II (Source; Wikipedia).

If I had to pick one unique or special feature about this particular fossil, it would have to be its likeness to the L. vulturinus holotype. One has to wonder, is this clay nodule similar to the one Professor Owen once held in his hands before erecting this new species to science? For me, it’s kind of a romantic thought.

Thursday, November 30, 2017

Rapidly evolving bird beaks

In case you missed it, an article worthy of more attention; 

New York Times Article by DOUGLAS QUENQUA NOV. 28, 2017In 

Things Looked Bleak Until These Birds Rapidly Evolved Bigger Beaks

Conservationists have been sounding the alarm over invasive species for years, warning of the damage they can cause to habitats and native animals. But in Florida, an invasive snail might be helping an endangered bird species come back from the brink, researchers say.

The population of North American snail kites — birds that use curved beaks and long claws to dine on small apple snails in the Florida Everglades — had been dwindling for years, from 3,500 in 2000 to just 700 in 2007. Things began to look particularly bleak in 2004, when a portion of the Everglades was invaded by a species of larger snail that the birds had historically struggled to eat. Ornithologists assumed the shift would hasten the snail kite’s decline.

A North American snail kite in Florida. Researchers say the bird species has rapidly evolved larger beaks and bodies to eat a larger, invasive snail.
 Credit Robert Fletcher/University of Florida 
http://avianmusing.blogspot.com/
But the number of snail kites in the Everglades grew over the decade following the invasion of the larger snails. The reason, according to a study published Monday in Nature Ecology and Evolution, is that the snail kites have rapidly evolved larger beaks and bodies to handle the bulkier snails.

“We were very surprised,” said Robert Fletcher, Jr., an ecologist at the University of Florida and an author of the study. “We often assume these large-bodied animals can’t keep up with changes to the system, like invasions or climate change, because their generation times are too long. And yet we are seeing this incredibly rapid change in beak size of this bird.”

Dr. Fletcher and his colleagues analyzed 11 years of morphological data they had collected on the birds. Because snail kites can live to the relatively old age of 8, that time period represented fewer than two generations for the birds.

Nonetheless, the researchers found that beak and body sizes had grown substantially (about 8 percent on average, and up to 12 percent) in the years since the invasion.

Exactly how the birds are pulling off this evolutionary trick is not clear, but natural selection does appear to play a part. Young snail kites with larger bills were more likely to survive their first year than snail kites with smaller bills, presumably because the large-billed birds were better able to eat the invasive snails.

The invasive snails are two to five times larger than the native species, and young kites with larger bills that were able to feed on them were more likely to survive their first year.

Robert Fletcher/University of Florida
http://avianmusing.blogspot.com/
Young birds eating the invasive snails, which are two to five times larger than the native ones, were also growing faster than birds weaned on the smaller ones, which may account for the increase in overall body size.

But the researchers found suggestions of a genetic component to the changes, as well. By tracking the birds’ pedigrees, they found that large-beaked parents gave birth to large-beaked offspring, setting the stage for large-scale evolutionary change.

Thirteen years after the larger snails invaded, the population of the birds has nearly tripled, to “well over 2,000,” Dr. Fletcher said. “It’s been a major development for the recovery of this species.” Outside of Florida, related snail kites are found in parts of South America, Central America and the Caribbean, where they are not considered endangered.

Overall, the findings are good news for animals squaring off against invasive species or other rapid habitat change, including global warming. “This work illustrates very clearly that these large top predators can respond to invasions at a rate much quicker than most people have ever imagined,” Dr. Fletcher said.

Saturday, November 25, 2017

Avian sternum evolution and developmental strategies

Finding answers to my peculiar scientific questions can sometimes be frustrating, especially when it pertains to a bird that has not fully developed yet. The bird I’m eluding to, whose weathered bones were found sitting at the bottom of a small cup nest, was juvenile in nature. Despite its very early age, many of the small bones were surprisingly familiar to me.

Salvaged from the nest were a tibiotarsus, ulna, carpometacarpus, and even a femur. Some of the bones uncovered were still in the process of development, like an unfused tarsometatarsus.
Juvenile bird bones
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
As excited as I was about these discoveries, there were other bones that were flat-out unfamiliar. One bone in particular was quite large, in comparison to the rest, and oddly shaped like a fossilized shark tooth. Where did this puzzle piece go?


Possible juvenile bird sternum
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
After some gritty research, and with much consideration, I came to a tentative conclusion that this bone was most likely part of the sternum. Was I correct? Granted, there isn’t much material out there regarding immature bird sternum identification, but I did manage to find a scientific paper with excellent information and possible clues.

Titled; “Insight into the early evolution of the avian sternum from juvenile enantiornithines”, the paper describes several new specimens of exceptionally well-preserved early juvenile enantiornithines fossils that, together with previously described specimens, show how the sternum, like in living birds, is a complex bone formed by several elements.


Sternal complexity comparable to living birds (for example, caudally extending processes, ventrally projecting carina) only appears in Ornithothoraces, the clade that includes the above mentioned Enantiornithes, the dominant group during the Cretaceous, and Ornithuromorpha, the group that includes living taxa (Neornithes).

However, the question still remained; could this paper provide enough information to support my claim?

Below are some excerpts from the paleontological study that I felt were pertinent to my investigation.  

To be clear, I believe this bone may well be part of the mesial caudal process, as depicted in the book; Avian Osteology by Gilbert, Martin and Savage, 1996. 
Mesial caudal process of sternum
Book photo credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
*The sternum of IVPP V15564 (institution where fossil is housed and catalog number) preserves three ossifications. The largest is caudally located and vertically symmetrical. Proximally, it forms a fan-shaped body with a convex rostral margin; distally it forms a long xiphoid process that always exceeds the rostral body in length. A slight ridge is present on the midline of this ossification, restricted to the caudal half; we infer this to be an early stage in the development of the osseous keel (Fig. 2e). This ossification has been previously observed in juvenile enantiornithines.


Figure 2, Enantiornithines sternal region
Photo Credit: http://www.nature.com/articles/ncomms2104
My thoughts after reading that were; could this juvenile bird bone be part of the caudal region, with the start of a long xiphoid process? During an early stage of growth, did sternal ossification in extant bird’s mirror enantiornithine development in any close way, prior to becoming surrounded by bone?


*Basal ornithuromorphs and enantiornithines show similar sternal morphologies, which suggests the fully modern sternum evolved only among more derived members of Ornithuromorpha, the Ornithurae. Unfortunately, no early juvenile ornithurines are recognized; however, given the derived appearance of the sternum we infer that development may have proceeded similarly to that of living birds. This is supported by the ossification of the sternum from a single pair of plates in most paleognaths indicating the plesiomorphic dinosaurian condition was retained in the lineage leading to modern birds. Enantiornithines are already known to have a developmental strategy different from most living birds in which they grew slowly for many years and spent extended periods of time as subadults, as evidenced from the large number of juvenile and subadult specimens uncovered. These specimens reveal early ontogenetic stages that allow us to understand the skeletal development of the clade. What has become apparent from this study is that, despite its superficially similar appearance, the enantiornithine sternum formed very differently from that of non-avian dinosaurs and living birds.

Again, the same question keeps coming to mind; in spite of its differing formation, would it be possible to use fossilized enantiornithine sternums in comparative studies with extant bird sternums, especially at an early ontogenetic stage? We can certainly do this with the tarsometatarsus, which is unfused and clearly mirrors the dinosaurian condition. Although treated as a single bone, the tarsometatarsus is actually formed by synostoses; in living birds, metatarsals IIIV start to fuse at the mid-shaft and fusion proceeds proximally and distally.

Juvenile bird tarsometatarsus
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
*As in living birds, the basal bird sternum was incompletely ossified in juveniles. The sternum of enantiornithines developed from four to six ossifications (Fig. 3). As in the morphological description, the sternal ossifications of enantiornithines will be referred to by their positions: proximal, caudal, lateral (paired) and craniolateral (paired, variably present). Although we will attempt to correlate these with ossification centers observed in living birds, the apparent lack of homology causes us to refrain from naming these ossifications according to previous literature. Given the diversity in the number of ossification centers in living taxa (two to seven), it would not be unexpected that there is similar diversity within Enantiornithes.

Figure 3, Interpretive drawing of the development of the enantiornithine sternum
Image credit: http://www.nature.com/articles/ncomms2104
*Ossification proceeds from the caudal half proximally, which is opposite to the direction of sternal development in living birds. The main body of the sternum in enantiornithines is formed by two ossifications, as in birds and non-avian dinosaurs, but instead of a bilaterally symmetrical pair, they are two proximo-distally arranged vertically symmetrical ossifications of very different morphology.

The researchers attempt to correlate sternal ossifications of enantiornithines, with ossification centers observed in living birds, vaguely reminds me my own similar efforts to unlock this unusually shaped bone’s true identification, though in a layman’s way of course. 
Possible juvenile bird sternum
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
The last two paragraphs also contradict my initial thoughts about the sternal development of this juvenile bone, leaving me once again frustrated.

I finally turned to a couple of wood warbler specimens that I have currently stored in my own collection. The one that held the most promise for side-by-side comparison was the Yellow Warbler (Setophaga petechia), which was not only my best-preserved specimen, but whose discovered nest matched perfectly to the species preferred breeding habitat and site location where it was found.  

Pinpointed under the microscope were two prospective sites. The first returned my attention to the mesial caudal region, where it looks as if the bone once again may be part of the sternum, and the initial formation of the sternal crest or keel.

Yellow Warbler (Setophaga petechial) sternum
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
Another possibility is the skull, more precisely the nasal-frontal region (Proctor; Manual of Ornithology. 1993). I feel less strongly about this option, but it is similar in shape and has to be considered.

Yellow Warbler (Setophaga petechial) nasal-frontal region
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
Then there is the chance that I am completely overlooking another location for this bone.

As I mention earlier in this post, there really isn’t much information out there regarding this topic, and when it is, it’s usually long outdated. For instance, some of the information cited in the paleontology paper date from 1868, 1939, 1960 and 1980. Images were also very hard to come by.    

Even though this may have been a futile attempt at scientific inquiry, I did foster a new-found appreciation for the development of the avian sternum. This study also helped satisfy my continuous need to learn more about the close relationship between birds and dinosaurs.

Saturday, November 11, 2017

Archaeopteryx toy figures; how scientifically accurate are they??

As a follow-up to my pictorial book review of Archaeopteryx; The Icon of Evolution by Dr. Peter Wellnhofer (see November 1st, 2017), I thought it would be interesting, and fun, to see how Archaeopteryx’s scientific restoration of its skeletal and outer appearance in life, compares with todays mass-produced toy figures. 


Archaeopteryx, The Icon of Evolution
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/

Toy figures, which are often sold in Natural History Museums, have a pretty strong following. So strong, that companies such as CollectA, Papo, Safari Ltd, Carnegie and Schleich continue to produce new figures, just to keep up with the public’s demand. These toys are not only manufactured for kids, but are now the target of more serious adult collectors. 

This has led to the creation of online communities dedicated solely to the discussion of prehistoric animal collectibles, paleoart, pop culture, and paleontology.


It is in these forums that eagerly awaited models are introduced and critiqued for their scientific accuracy and artistic originality. 

I will be evaluating five Archaeopteryx figures today for accurate feather placement, teeth, wing claws and overall shape. Another important feature is plumage coloration. 


Archaeopteryx Toy Figures
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
In 2011, graduate student Ryan Carney and colleagues performed the first color study on an Archaeopteryx specimen. Using scanning electron microscopy technology, the team was able to detect the structure of melanosomes in the single-feather specimen described in 1861 (Source: Wikipedia). The resultant structure was then compared to that of 87 modern bird species and was determined with a highest likelihood to be black.

At the conclusion of each evaluation, I will rate the figure from 1 through 10, based on the key features mentioned above. I will also take a more thorough look at the first figure, letting the reader revert back to this evaluation for further reference. 

Wild Safari by Safari Ltd. 

Since I just touched on the topic of Archaeopteryx’s recently discovered black coloration, it only seems right that I start with an actual black-colored figure. Wild Safari’s toy figure offers consumers the best of both worlds. It not only has the ability to inspire young kids, but satisfy the pickiest of adult collectors.

The black colored plumage with iridescent sheen is beautifully done, as well as scientifically accurate. In many places the finer structures of the feathers can be determined, especially the barbs branching off the shafts. The feathered lower leg corresponds well with preserved feathers in the Berlin specimen. In general, the feathers throughout the figure are positioned correctly.


Wild Safari Archaeopteryx
Photo credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
The figures structure is proportionally sound. I like the way you can see the curves of the body, long s-shaped neck, chest, even leg musculature. The skull is the appropriate size and shape, with a nicely done eye. Teeth are fully present. 

A couple downfalls of the Wild Safari Archaeopteryx figure include the exaggerated hyper-extensible sickle-clawed second toe. Though its supported by some researchers, Wellnhofer states that such a function would appear to be quite impossible, the more so as the ungual and its keratinous claw of the second toe is of normal size. It is obvious that a greater extension of the second toe was possible in Archaeopteryx, but there is no evidence as to which special function this toe should have been adapted (Wellnhofer; 2009). 

The fingers of the hand, according to the book, are also incorrectly reconstructed. The first should be sticking out freely, while the second and third digits only the claws are protruding. Speaking of claws, I don’t understand the blunt-ended nature of both the finger and toes. It looks a little unusual.  

My final problem with the figure involves the feathers of the wing. The fact that all flight feathers in the wing were preserved in their natural position (fossil specimens), and not separated from the bone, is indirect evidence for their firm connection. With that being said, the long humerus is devoid of feathers. This suggests that there was a gap in the plumage between the inner wing (secondaries) and the body (Wellnhofer; 2009). There is no sign of a gap between the secondaries and body on this figure.

Even with these faults, the Wild Safari Archaeopteryx is a well- researched and an almost perfect reconstruction. Rating: 8

Papo Archaeopteryx

At first glance, you may mistake this figure for another feathered raptor, like the Bullyland Velociraptor. Despite being similar to other famous raptors on the market, the Papo Archaeopteryx does offer some unique attributes of its own.

The feathers for one appear individually crafted, with a layered look, and feel that is rarely found on other toys today. Very well done. A gap in the plumage between the inner wing (secondaries) and the body is not present, however the tertials are noticeably shorter (partial credit for this).  

The tail on the Papo Archaeopteryx is spot-on according to the Wellnhofer book. Rectrices on the figure correspond well with the Berlin and London specimens, including the rounded feathers at its distal end. 


Papo Archaeopteryx
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
The artist choice for a brownish/cream color scheme is tastefully done.

The hand and toe claws are noticably sharp on this Archaeopteryx model.

The evenly-spaced teeth are another nice feature of this toy. Paleontologists and collectors alike will certainly recognize the importance of Archaeopteryx’s evenly-spaced teeth. In between the mandibular teeth interdental plates are developed, as documented in the Munich specimen for the first time (Wellnhofer. 2009). Except for Archaeopteryx, in no other toothed bird are interdental plates known.


Papo Archaeopteryx
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
Like all toy figures, there are some obvious discrepancies. The legs on the Papo Archaeopteryx are unfortunately a little off course. Their short-bulky appearance is reminiscent of body-builder’s physique. Also, the placement of the crural feathers extend further down onto the metatarsals than I would like to see, rather than ending on the tibiotarsus as preserved on the Berlin specimen. 

The fingers of the hand, according to the book, are also incorrectly reconstructed. The first should be sticking out freely, while the second and third digits only the claws are protruding.

The snout also seems to be a bit too robust, and more dromaeosaur-like. 

The most striking feature on this figure is located along its crown. Eighteen red quill-like feathers (or are they fleshy horns (lappets), create an unnecessary eye-sore on an otherwise nice toy figure. Was its inspiration taken from a Temminck's tragopan? Rating: 6


Temminck's Tragopan Taxidermy
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
Kinto Favorite Collection soft models Archaeopteryx

Here is another high-quality toy figure from the company, Kinto Favorite Collection soft models. The only Archaeopteryx figure to feature its own pedestal. 


Kinto Favorite Archaeopteryx
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
It is with this pedestal that the Kinto Archaeopteryx is able to be positioned in a running pose, which is in contrast to most figures that appear to be just ‘standing around’. This position also allows the collector to gauge the proportion of this model, which seems accurate.  

The feathers on this figure are adequately formed. They are detailed; however, it takes a microscope to find that out. The choice of colors is easy on the eyes. Dark, medium and light gray’s is about as close to scientifically accurate as you can get, without going there.   

The crural feathers are quite evident and corresponds well with preserved feathers in the Berlin specimen, especially on the extended leg. 

The tail on the Kinto Archaeopteryx is nearly perfect according to the Wellnhofer book. Rectrices on the figure correspond well with the Berlin and London specimens, including the rounded feathers at its distal end. I also like the constriction at the base of the tail which is consistent with the fossil evidence.

The wing and toe claws barely pass for acceptable, showing a slight sharpness to them. The hyper-extensible sickle-clawed second toe is discernable, but not in your face like Wild Safari’s.

The problems with this model include the fingers of the hand, which according to the book, are also incorrectly reconstructed. The first should be sticking out freely, while the second and third digits only the claws are protruding.

The gap in the plumage between the inner wing (secondaries) and the body is not present, with no effort to do so. 

I like the detail on the skull of this Archaeopteryx, however the design of the teeth left much to be desired, which is unfortunate. They are entirely missing on the lower mandible. Rating: 7


Kinto Favorite Archaeopteryx
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/

Archaeopteryx from PNSO

Even though the PNSO Archaeopteryx is not positioned on a stand-alone pedestal like the Kinto model, it still presents the toy in a highly unusual pose. As if caught in the act of a mating display, the PNSO Archaeopteryx features outstretched forelimbs, a tucked in leg and raised tail. This posture will allow for a more thorough examination of this figures details. 


PNSO Archaeopteryx
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
In many areas the finer structures of the feathers can be determined, especially the barbs branching off the shafts. Wing coverts have a layered look and feel to them, not an easy feature to get right on such a small replica. The feathered lower leg corresponds well with preserved feathers in the Berlin specimen. Overall, the feathers throughout this Archaeopteryx are positioned accurately. 

The brown and gray color scheme is an appealing and a safe choice, but mirrors the Kinto model almost to a tee. 

The figure, in general, appears properly proportioned.  

The fingers of the hand, according to the book Archaeopteryx; The Icon of Evolution, are correctly reconstructed. The first is sticking out freely, while the second and third digits only the claws are protruding. But there are imperfections. The claws on the fingers are blunt and one is painted over gray, not greenish-yellow like the other two. The claws on the toes are also rounded. 

The tail and its feathers are distally narrow, a possible necessity to keep this model balanced.

The gap in the plumage between the inner wing (secondaries) and the body is not present. 

Since the jaw is closed shut, it is hard to judge, or even see the teeth on this figure. However, it does show some similarities (under the microscope) to the Eichstatt specimen of Archaeopteryx showing a slight overbite, premaxillary and maxillary with teeth. Downfall, they are not painted and are virtually invisible. Rating: 6  

Bullyland Archaeopteryx (blue morph)

This will be my final review of Archaeopteryx toy figures. With its feet firmly secured to a small baseplate, the Bullyland Archaeopteryx features a forward leaning posture which allows its tail to be lifted to near horizontal plane. Curiously, this posture contrasts sharply with all the other Archaeopteryx figures which show tripod, wing and pedestal support. 

There are feathers located throughout the body on this figure, but only on the wing does one find feathers individually sculpted. Beyond that, there is no other finer details.  The feathers on the lower leg do not correspond with preserved feathers in the Berlin specimen.

The tail on the Bullyland Archaeopteryx appears too short, lending to an already front-end heavy appearance. Rectrices on the figure correspond well with the Berlin and London specimens, including the rounded feathers at its distal end. 

Clearly the most accurate feature on this Archaeopteryx figure is the gap in the plumage between the inner wing (secondaries) and the body. Finally, I can state that yes, the gap is present! 


Bullyland Archaeopteryx
Photo Credit: Paul Cianfaglione
http://avianmusing.blogspot.com/
Plumage coloration itself is adequate at best. 

The fingers of the hand are all incorrectly reconstructed. All three digits protrude beyond the feathering. Claws on the fingers are curved and barely pass for sharp. Same goes for the toe claws.

The skull has a long, bizarre look to it. This Archaeopteryx looks as if its grinning, showing off its horribly designed teeth. Ranking: 4