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3. A previously unreported form of dorsal rib pneumaticity in Apatosaurus (Dinosauria: Sauropoda) and implications for pneumatic variation among diplodocid dorsal ribsCitation for this article: King, J. L., Mchugh, J. B., Wedel, M. J., & Curtice, B. (2024) A previously unreported form of dorsal rib pneumaticity in Apatosaurus (Dinosauria: Sauropoda) and its implication for pneumatic variation among diplodocid dorsal ribs. Journal of Vertebrate Paleontology . https://doi.org/10.1080/02724634.2024.2316665

Author

Logan King, J., primary, McHugh, Julia B., additional, Wedel, Mathew J., additional, and Curtice, Brian, additional

Published
2024
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5. Star Crossed.

Author

Wedel, Mathew

Subjects
*STARS, *SOLAR system, *VARIABLE stars, *SMALL magellanic cloud, *OPEN clusters of stars, *RR Lyrae stars, *GLOBULAR clusters
Abstract

The article "Star Crossed" offers a comprehensive guide to celestial events and phenomena visible in the sky during October 2024. It covers various topics such as the zodiacal light, the positions of celestial bodies like the Moon, Venus, Saturn, and Jupiter, and the Orionid meteor shower. The article also provides a lunar almanac and a sky chart specifically designed for the northern hemisphere. Furthermore, it offers insights into observing the carbon star TX Piscium in the constellation Pisces, known for its striking red color and variable brightness. The article suggests using binoculars to locate the star near the Circlet of Pisces and provides a nearby asterism for comparison. Lastly, the text includes a Southern Hemisphere sky chart featuring the constellation Indus. [Extracted from the article]

Published
2024

8. Postcranial pneumaticity in dinosaurs and the origin of the avian lung

Author

Wedel, Mathew John

Subjects
Quantitative Biology - Tissues and Organs, Quantitative Biology - Populations and Evolution
Abstract

In birds, diverticula of the lungs and air sacs pneumatize specific regions of the postcranial skeleton. Relationships among pulmonary components and skeletal regions they pneumatize allow inferences about pulmonary anatomy in non-avian dinosaurs. Fossae, foramina and chambers in the postcranial skeletons of pterosaurs and saurischian dinosaurs are diagnostic for pneumaticity. In basal saurischians only the cervical skeleton is pneumatized, by cervical air sacs. In more derived saurischians pneumatization of posterior dorsal, sacral, and caudal vertebrae indicates abdominal air sacs. Abdominal air sacs in sauropods are also indicated by a pneumatic hiatus (a gap in vertebral pneumatization) in Haplocanthosaurus. Minimally, saurischians had dorsally attached diverticular lungs plus anterior and posterior air sacs, and all the pulmonary prerequisites for flow-through lung ventilation like that of birds. Pneumaticity reduced skeletal mass in saurischians. I propose the Air Space Proportion (ASP) as a measure of proportional volume of air in pneumatic bones. The mean ASP of a sample of sauropod and theropod vertebrae is 0.61, so on average, air occupied more than half the volume of these vertebrae. In Diplodocus, pneumatization lightened the living animal by 7-10 percent, and that does not include extraskeletal diverticula, air sacs, lungs, or trachea. If all these air reservoirs included, the specific gravity of Diplodocus is 0.80, higher than published values for birds but lower than those for squamates and crocodilians. Pneumatization of cervical vertebrae facilitated evolution of long necks in sauropods. Necks longer than nine meters evolved at least four times, in mamenchisaurs, diplodocids, brachiosaurids, and titanosaurs. Increases in the number of cervical vertebrae, their proportional lengths, and their internal complexity occurred in parallel in most of these lineages., Comment: PhD dissertation, University of California, Berkeley, Department of Integrative Biology, May 2007, 303 pages

Published
2013

9. Why sauropods had long necks; and why giraffes have short necks

Author

Taylor, Michael P. and Wedel, Mathew J.

Subjects
Quantitative Biology - Tissues and Organs, Quantitative Biology - Populations and Evolution
Abstract

The necks of the sauropod dinosaurs reached 15 m in length: six times longer than that of the world record giraffe and five times longer than those of all other terrestrial animals. Several anatomical features enabled this extreme elongation, including: absolutely large body size and quadrupedal stance providing a stable platform for a long neck; a small, light head that did not orally process food; cervical vertebrae that were both numerous and individually elongate; an efficient air-sac-based respiratory system; and distinctive cervical architecture. Relevant features of sauropod cervical vertebrae include: pneumatic chambers that enabled the bone to be positioned in a mechanically efficient way within the envelope; and muscular attachments of varying importance to the neural spines, epipophyses and cervical ribs. Other long-necked tetrapods lacked important features of sauropods, preventing the evolution of longer necks: for example, giraffes have relatively small torsos and large, heavy heads, share the usual mammalian constraint of only seven cervical vertebrae, and lack an air-sac system and pneumatic bones. Among non-sauropods, their saurischian relatives the theropod dinosaurs seem to have been best placed to evolve long necks, and indeed they probably surpassed those of giraffes. But 150 million years of evolution did not suffice for them to exceed a relatively modest 2.5 m., Comment: 39 pages, 11 figures, 3 tables

Published
2012
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12. Where Secrets Are Kept.

Author

Wedel, Mathew

Subjects
*SMALL magellanic cloud, *OPEN clusters of stars, *RR Lyrae stars, *PLANETARY nebulae, *LARGE magellanic cloud, *VARIABLE stars, *GLOBULAR clusters
Abstract

This publication from Sky & Telescope titled "Where Secrets Are Kept" provides a lunar almanac for September 2024, including moon phases, distances, and favorable librations. The author also discusses the heart asterism in the constellation Cygnus, with its center star Sadr. They express their fascination with the beauty and mystery of the night sky and their eagerness to continue exploring it. The article further explores the constellation Pavo, also known as the Peacock, which contains the bright star Alpha Pavonis and the globular star cluster NGC 6752. It also provides information on various celestial objects such as galaxies, variable stars, open clusters, diffuse nebulae, globular clusters, and planetary nebulae. [Extracted from the article]

Published
2024

14. Living on the Edge.

Author

Wedel, Mathew

Subjects
*MAIN sequence (Astronomy), *STARS, *LUNAR eclipses, *OPEN clusters of stars, *SMALL magellanic cloud
Abstract

The article titled "Living on the Edge" provides information on various celestial events that can be observed in May 2024. It mentions the positions of the Moon, Saturn, and Mars in the sky, as well as the peak of the Eta Aquariids meteor shower. The article also provides details on the positions of the Moon and various stars throughout the month. The article is a useful resource for individuals interested in observing celestial phenomena during May 2024. Additionally, it briefly mentions the constellation Musca, which is named after a fly and contains a few notable stars. [Extracted from the article]

Published
2024

15. Whirlpool Time Machine.

Author

Wedel, Mathew

Subjects
*OPEN clusters of stars, *SMALL magellanic cloud, *RR Lyrae stars, *LARGE magellanic cloud, *TOTAL solar eclipses, *VENUS (Planet)
Abstract

This article from Sky & Telescope offers a comprehensive guide to celestial events and observations in April 2024. It covers various topics such as the position of the Moon, meteor showers, solar eclipses, and the movements of planets like Mars and Saturn. The article includes a lunar almanac and a sky chart specifically designed for the Northern Hemisphere. It is a valuable resource for individuals interested in astronomy and stargazing. Additionally, the article discusses the observation of Messier 51, also known as the Whirlpool Galaxy, located in the constellation Canes Venatici. The author provides instructions on how to locate the galaxy using the Big Dipper asterism in Ursa Major. While visible in binoculars, larger binoculars or telescopes are needed to see its details. The article also mentions that the Whirlpool Galaxy is approximately 30 million light-years away. The author reflects on the perspective gained from observing distant objects in the night sky and the connection to our own history. Lastly, the article briefly mentions the constellation Vela in the southern sky and highlights some interesting stars within it. [Extracted from the article]

Published
2024

16. The Hot New Thing.

Author

Wedel, Mathew

Subjects
*STARS, *SMALL magellanic cloud, *STELLAR winds, *LARGE magellanic cloud, *EARLY stars, *VARIABLE stars, *GLOBULAR clusters
Abstract

"The Hot New Thing" is a document that provides a lunar almanac and sky charts for January 2025. It offers information on moon phases, distances, and favorable librations, as well as highlighting observing targets like Orion's Belt. The article encourages readers to explore the beauty and significance of observing celestial objects. It also provides information about the constellation Dorado, which is named after the mahi-mahi or dolphinfish, and contains the Large Magellanic Cloud (LMC) and the Tarantula Nebula. Dorado has two notable stars, Alpha Doradus and Beta, with contrasting colors and varying magnitudes. [Extracted from the article]

Published
2025

17. A well-preserved vertebra provides new insights into rebbachisaurid sauropod caudal anatomical and pneumatic features.

Author

WINDHOLZ, GUILLERMO J., PORFIRI, JUAN D., SANTOS, DOMENICA DOS, BELLARDINI, FLAVIO, and WEDEL, MATHEW J.

Subjects
VERTEBRAE, COMPUTED tomography, DINOSAURS, AIR-supported structures, SAURISCHIA
Abstract

Rebbachisauridae is a clade of sauropod dinosaurs whose maximum diversification and abundance are known from the Cretaceous of South America. We describe an anterior caudal vertebra, MDPA-Pv 007, from the Upper Cretaceous of Argentine Patagonia, whose characters allow it to be referred to this clade. Also, two phylogenetic analyses reinforce the referral of the new material more exclusively to Rebbachisaurinae. We analyze pneumatic structures using the first CT scans of a caudal element of a rebbachisaurid. The excellent preservation of MDPA-Pv 007, combined with CT images, allows us to document external fossae and foramina that connect to larger internal chambers, constituting unambiguous evidence of pneumaticity. The centrum of MDPA-Pv 007 is camerate, with large interconnected internal chambers; this is accompanied by a neural arch with wide and deep fossae. Caudal pneumaticity has a complex phylogenetic distribution among neosauropods. This feature may have evolved independently in diplodocoids and titanosauriforms, or it could be ancestral for Neosauropoda but secondarily lost in a few lineages. Future investigations, taking advantage of new technologies, will provide insights into the phylogenetic distribution and paleobiological implications of pneumaticity in sauropod dinosaurs and other fossil archosaurs. [ABSTRACT FROM AUTHOR]

Published
2024
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18. In the Mouth of the Dragon.

Author

Wedel, Mathew

Subjects
*ASTRONOMERS, *SMALL magellanic cloud, *OPEN clusters of stars, *RR Lyrae stars, *VARIABLE stars, *VENUS (Planet)
Abstract

The article "In the Mouth of the Dragon" discusses the observation of the double star Nu Draconis in the Draco constellation. This star system consists of two equally bright white A-type dwarfs that are currently about 1 arcminute apart. Observing Nu Draconis can be a test of binocular resolving power and grip steadiness. The article also mentions the globular star cluster Omega Centauri (NGC 5139), which is visible in the southern sky. Omega Centauri is the largest bright nebula in the southern hemisphere and can be seen with the naked eye. Some astronomers believe it is the core of a disrupted dwarf galaxy, with a size of approximately 150 light-years and a mass of about 4 million Suns. [Extracted from the article]

Published
2024

20. Novel pneumatic features in the ribs of the sauropod dinosaur Brachiosaurus altithorax.

Author

TAYLOR, MICHAEL P. and WEDEL, MATHEW J.

Subjects
*DINOSAURS, *TWENTIETH century, *SAURISCHIA
Abstract

Pneumatic dorsal ribs are known for many sauropods, but to date costal pneumaticity has received relatively little attention. In particular, the pneumatic ribs of the holotype specimen of Brachiosaurus altithorax have been largely overlooked, although they present a unique configuration of pneumatic features. One rib, with a pneumatic foramen some distance down the shaft, was briefly described and illustrated in the early 20th century by Elmer S. Riggs. A second rib with a pneumatic foramen in the tuberculum of the rib has not previously been described or illustrated. This previously undescribed foramen is similar in location to those in some dorsal ribs of Brontosaurus excelsus and Giraffatitan brancai, but differs from them in both size and shape. The contrasting sites of costal pneumaticity in the holotype individual of Brachiosaurus altithorax emphasize the generally opportunistic mode of postcranial pneumatization, in both sauropods and other ornithodirans, but conform to models of pneumatization following vascularization. [ABSTRACT FROM AUTHOR]

Published
2023
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21. A Previously Unreported form of Dorsal Rib Pneumaticity in Apatosaurus (Dinosauria: Sauropoda) and Implications for Pneumatic Variation among Diplodocid Dorsal Ribs.

Author

King, J. Logan, Mchugh, Julia B., Wedel, Mathew J., and Curtice, Brian

Abstract

Postcranial pneumaticity is interpreted as a weight saving adaptation in sauropod dinosaurs, especially in the vertebral column. In some derived sauropods pneumatic features also occur on vertebral ribs. While pneumatic ribs are considered diagnostic of the clade Titanosauriformes, they are also infrequently found in diplodocid sauropods. Here, we describe a partial dorsal rib IV or V referable to Apatosaurus sp. that exhibits a series of superficial pneumatic fossae along its posterior surface. These fossae differ from the morphology found in other pneumatic dorsal ribs of diplodocids, including other apatosaurines and Supersaurus. Moreover, the pneumatic features of this rib are more distally located from the capitulum and tuberculum than in other diplodocids and titanosaurs. Based on our findings, we propose that rib pneumaticity among apatosaurine sauropods (and potentially all diplodocids) is individually variable, in addition to being a function of ontogeny. More broadly, we conclude that rib pneumaticity among diplodocids is morphologically variable when present and individually expressed rather than being ubiquitous throughout the clade. Our findings are consistent with the hypothesis that pneumatic ribs evolved independently between Diplodocidae and Titanosauriformes and make for poor clade-level characters among diplodocids. [ABSTRACT FROM AUTHOR]

Published
2023
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22. What do we mean by the directions 'cranial' and 'caudal' on a vertebra?

Author

Taylor, Michael P and Wedel, Mathew

Subjects
vertebra, orientation, cranial, caudal, horizontal, neural canal
Abstract

When describing and illustrating vertebrae, it is important to consistently depict their orientation, so we can objectively assess and compare the slope of the neural arch, neural canal, or articular surfaces. However, differing vertebral shapes across taxa and across regions of the spinal column make it difficult to maintain consistency, or even define what we mean by the directions “cranial” and “caudal”. Consequently, characters such as “Neural arch slopes cranially 30° relative to the vertical” are disputable rather than objective measurements. Cranial and caudal are defined as directed along the horizontal axis, but several different definitions of “horizontal” are possible:1. Long axis of centrum is horizontal. This is appealing for elongate vertebrae such as sauropod cervicals, but is not always well defined, and is difficult to determine for craniocaudally short vertebrae such as most caudals.2. Articular surfaces of centrum are vertical. Difficult to determine when dealing with facets that are concave or (worse) convex; and ambiguous for “keystoned” vertebrae in which the facets are not parallel.3. Neural canal is horizontal. Anatomically informative, but difficult to determine in vertebrae that have not been fully prepared or CT-scanned, and impossible to see in lateral view. Ambiguous for vertebrae where the dorsal and ventral margins of the canal are not straight or not parallel.4. Similarity in articulation (“horizontal” is defined as a line joining the same point on two similarly oriented copies of the same vertebra when optimally articulated). This is less intuitive than definitions 1–3, but takes the entire vertebra into account.We advocate explicitly stating a definition and using it consistently. In most cases, definition 3 (“Neural canal is horizontal”) best reflects anatomical and developmental realities, and it is therefore preferred. Low-tech methods can be used to determine neural canal orientation with adequate precision for most purposes.

Published
2022

25. Eves of the dragon: look the fiery beast in the face as you track down these binocular doubles in Draco

Author

Wedel, Mathew

Subjects
Observational astronomy -- Methods, Binary stars -- Observations -- Natural history, Draco (Constellation) -- Natural history -- Observations, Astronomy
Abstract

Observing double stars with binoculars might seem like a crazy pursuit. Many double star observers like to challenge themselves by splitting tight doubles; however, the low magnifications of binoculars put [...]

Published
2017

26. Easy and hard

Author

Wedel, Mathew

Subjects
Stars -- Open clusters, Observational astronomy -- Methods, Binoculars -- Usage, Perseus (Constellation) -- Observations, Astronomy
Abstract

Here's a fun field with which to push your observing abilities. Starting at Alpha (α) Persei (Mirfak), the brightest star in the constellation Perseus, follow the J-shaped chain of stars [...]

Published
2017

29. Unresolved Matter.

Author

Wedel, Mathew

Subjects
*STARS, *OPEN clusters of stars, *RR Lyrae stars, *LUNAR phases, *PLANETARY nebulae, *VARIABLE stars
Abstract

The article titled "Unresolved Matter" provides information on observing the Triangulum Galaxy (M33) using binoculars. M33 is the third-largest galaxy in the Local Group and is known for its nearly face-on orientation. However, its faint surface brightness can make it challenging to observe, especially in areas with light pollution or thin clouds. The author recommends finding dark skies and using 7x50 binoculars to enhance visibility. Despite the lack of resolution, observing galaxies with binoculars allows for a unique experience of seeing stars as a faint fog of light. [Extracted from the article]

Published
2024

31. Big Sky Country

Author

Wedel, Mathew

Subjects
Open clusters -- Observations, Astronomy -- Observations, Astronomical rotation -- Observations, Planets -- Observations, Astronomy
Abstract

When I first got into amateur astronomy in the fall of 2007, Cassiopeia was my first constellation. In the era before smartphones and astronomy apps, I learned the sky the [...]

Published
2017

33. Binocular holiday: take a guided tour of the Milky Way's top attractions

Author

Wedel, Mathew

Subjects
Milky Way -- Observations, Observational astronomy -- Methods, Constellations -- Observations, Astronomy
Abstract

IN THE CRISP WINTER SKIES, the Milky Way seems to bend slightly closer to the Earth, inviting us to a deeper appreciation of its glittering starfields. Plus, it's usually darned [...]

Published
2015

36. Heroes Across Time.

Author

Wedel, Mathew

Subjects
*RR Lyrae stars, *LUNAR phases, *PLANETARY nebulae, *NEW moon, *BINARY stars, *VARIABLE stars, *OPEN clusters of stars
Abstract

The article titled "Heroes Across Time" discusses the Alpha Persei Association, also known as the open cluster Melotte 20, located in the constellation Perseus. The cluster is the largest and brightest deep-sky object in Perseus and spans approximately 3 degrees. It contains stars ranging in magnitude from 1.8 to the limit of the observer's instrument, as well as binocular doubles and chains and loops of stars. The article also mentions the presence of the 8th-magnitude open cluster NGC 1245, located southwest of Alpha Persei. [Extracted from the article]

Published
2024

37. Drifting Apart.

Author

Wedel, Mathew

Subjects
*OPEN clusters of stars, *RR Lyrae stars, *ASTRONOMERS, *LUNAR phases, *VARIABLE stars, *PLANETARY nebulae
Abstract

The article titled "Drifting Apart" discusses the open cluster Collinder 359, also known as Melotte 186. The cluster is located near Gamma (γ) Ophiuchi in the constellation Ophiuchus. It can be observed using binoculars, with 7x50 or 10x50 binoculars providing the best view. Collinder 359 is similar in distance and proper motion to the nearby open cluster IC 4665, but the stars in Collinder 359 have started to drift apart, highlighting the process of galactic evolution. [Extracted from the article]

Published
2024

43. The past, present and future of Jensens 'Big Three' sauropods

Author

Taylor, Michael P and Wedel, Mathew J

Abstract

In the 1970s, Jim Jensen excavated multiple gigantic sauropod dinosaurs from Dry Mesa Quarry (DMQ), Colorado. In 1985, he formally named Supersaurus , Ultrasaurus (later Ultrasauros ), and Dystylosaurus based on these specimens. Later, Brian Curtice and coauthors referred the holotype vertebrae of Ultrasauros and Dystylosaurus to Supersaurus , and the referred scapulocoracoid of Ultrasauros to Brachiosaurus . In 2016, we determined that a large cervical vertebra referred to Supersaurus in fact belongs to Barosaurus . Either Supersaurus is synonymous with Barosaurus , or it is distinct but some Barosaurus material has been incorrectly referred. The holotype of Dystylosaurus , an anterior dorsal vertebra, cannot belong to Barosaurus due to its unsplit neural spine, but no shared apomorphies support its referral to Supersaurus and the convenient referral of all large diplodocid material from DMQ to Supersaurus is no longer supportable in light of the Barosaurus cervical. Nomenclatural issues pertaining to Supersaurus must be resolved by reference to its holotype scapulocoracoid. Jensen assigned two scapulocoracoids to Supersaurus , but his vague descriptions, and pervasive confusion around published specimen numbers, make it uncertain which of the two is the type. The two elements have subtle differences and may not belong to the same animal. This is unfortunate, since Supersaurus is the most complete, phylogenetically informative, and nomenclaturally stable of the “Big Three” Dry Mesa sauropods — or at least it was until now. Finally, while the scapulocoracoid referred to Ultrasauros is probably from a titanosauriform, its coracoid does not closely resemble that of the holotype of Brachiosaurus , nor its scapulae those of Giraffatitan . In summary, the DMQ material includes at least three giant sauropods: a titanosauriform that may not be Brachiosaurus , and two diplodocids: Barosaurus and Supersaurus – but the diagnosis of the latter is muddied both by possible confusion with Barosaurus , and by definite confusion regarding the holotype.

Published
2019
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44. Neural canal ridges: A novel osteological correlate of post-cranial neurology in dinosaurs

Author

Atterholt, Jessie and Wedel, Mathew J

Subjects
musculoskeletal diseases, medicine.medical_specialty, medicine.anatomical_structure, Neurology, Osteology, medicine, Anatomy, Denticulate ligaments, Neural Canal, Biology, Spinal cord, musculoskeletal system
Abstract

Bony ridges occur on the walls of the neural canal in caudal vertebrae of numerous sauropod dinosaurs. These neural canal ridges (NCRs) are anteroposteriorly elongated but do not extend to the ends of the canal. To date, we have observed NCRs in caudal vertebrae of Alamosaurus, Apatosaurus, Astrophocaudia,Brontomerus, Camarasaurus, and Diplodocus. Numerous similar structures occur in extant vertebrates: (1) Neurocentral joints are ventral to NCRs in sauropod caudal vertebrae, and NCRs occur in unfused juvenile arches. Hypothesis rejected. (2) Attachment scars from ligamentum flavum occur at the ends of the dorsal roof of the canal, not the midpoint of the lateral edges, and this mammalian ligament was probably absent in dinosaurs. Hypothesis rejected. (3) Smooth ridges separate the spinal cord from the dorsal spinal vein and paramedullary airways in some crocodilians and birds, respectively. However, these septa persist to the ends of the canal, giving it an 8-shape, unlike the discrete NCRs of dinosaurs. Hypothesis rejected. (4) Bony attachments for denticulate ligaments occur in some non-mammalian vertebrates. The dura mater around the spinal cord fuses to the periosteum of the neural canal in non-mammals, so the denticulate ligaments that support the spinal cord can leave ossified attachment scars. These spinal cord supports have been identified in teleosts, salamanders, and a juvenile lizard, and they are the best match for the morphology of the NCRs in sauropod vertebrae. Functions of NCRs remain obscure. Denticulate ligaments are largest in regions of the vertebral column that experience strong lateral flexion. The hypothesis that NCRs supported the spinal cord of sauropods during lateral tail-whipping is attractive, but inconsistent with our recent discovery of NCRs in a hadrosaur caudal. NCRs are a new osteological correlate of the peripheral nervous system in dinosaurs, and highlight the need for more study in this area.

Published
2019
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46. A CT-based survey of supramedullary diverticula in extant birds

Author

Atterholt, Jessie and Wedel, Mathew J

Subjects
medicine.anatomical_structure, medicine.diagnostic_test, Extant taxon, business.industry, Medicine, Computed tomography, Anatomy, Neural Canal, business, Spinal cord, digestive system, digestive system diseases
Abstract

Birds are unique among extant tetrapods in having pneumatic diverticula of the lungs and air sacs that pass among the viscera and muscles, under the skin, and into the skeleton. In addition, some birds also have supramedullary diverticula inside the neural canal, adjacent to the spinal cord. The anatomy of the supramedullary diverticula has only been documented in a handful of birds to date. Using CT scans, we surveyed the morphology of the supramedullary diverticula in a phylogenetically broad sample of extant birds. Although supramedullary diverticula are present in some small-bodied taxa such as hummingbirds and pigeons, the diverticula are typically larger and more complex in large forms such as ostriches and pelicans. Absence of these diverticula in loons and grebes is consistent with the lack of skeletal pneumatization in diving birds. Other absences, for example in the kestrel, are less explicable. When present, the supramedullary diverticula are best developed in presacral vertebrae, but only occasionally present in the synsacrum, and rarely present in caudal vertebrae. In most taxa we have surveyed, the diverticula are not continuous craniocaudally, but exist as separate segments extending fore and aft from each intervertebral joint, as documented by Müller for the pigeon. Occasionally supramedullary diverticula communicate with interosseous diverticula through foramina in the wall or roof of the neural canal. These foramina are osteological correlates of supramedullary diverticula and allow the presence of these diverticula to be inferred in dry skeletal material and fossil organisms.

Published
2018

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