New Publication: Vomeronasal and Olfactory Structures in Bats Revealed by DiceCT Clarify Genetic Evidence of Function

3D Bat Vomeronasal Organs
Coronal sections of the posterior region of the nasal cavity comparing diceCT scans and 3D reconstructions in bats (frontoturbinal is light green; interturbinals are dark green, ethmoturbinal I is yellow; ethmoturbinal II is light blue; and ethmoturbinal III is teal; see publication for abbreviations.)

“Bats demonstrate one of the most impressive stories of independent loss of the vomeronasal organ, a specialized nasal pheromone-sensing system in mammals. We were surprised to learn of a loss-of-function mutation in a vomeronasal-specific gene within a clade of Caribbean nectar-feeding bats, as many of their mainland relatives maintain function of the gene and organ—but the morphology was not known for this clade. DiceCT permitted us to peek inside the heads of these bats and characterize the nasal soft tissues, including the first 3D reconstruction of a vomeronasal organ, a structure only thought visible through histology. We discovered that Caribbean nectarivorous bats indeed have lost or reduced the vomeronasal organ and possess more elaborate olfactory turbinals. Complete loss of morphology likely occurred prior to complete genetic loss of function revealing a deeper understanding of the process of vestigalization.”

– co-lead authors, Laurel Yohe (@) & Simone Hoffmann (@)

Head over to Frontiers in Neuroanatomy to read the pub and see more research on Twitter!

Featured Editorial Team: The Anatomical Record

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“The ability to visualize structures in three-dimensional space will revolutionize how we can evaluate biomechanics in a wholly non-destructive approach. In addition, the possibility of algorithmic approaches (like those published recently by Dickinson and colleagues) will improve repeatability, and likely will help us save data collection time.”

– Adam Hartstone-Rose,

Traditional methods get paired with new imaging techniques to advance the study musculoskeletal biomechanics, featured in the February and March 2018 Special Issues of The Anatomical Record edited by Hartstone-Rose and his colleagues Sharlene Santana, Damiano Marchi, & Jeffrey T. Laitman.

New Publication: Assessment of the Hindlimb Membrane Musculature of Bats: Implications for Active Control of the Calcar

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3D diceCT models and histological sections through the calcar of (a) Myotis californicus, (b) Artibeus jamaicensis, (c,d) Molossus molasses. Specimens were stained with Lugol’s iodine for contrast-enhanced X-ray µCT imaging, subsequently destained by leaching in 70% EtOH, and re-stained for histological sectioning using Modified Mayer’s Hematoxylin and Mallory triple connective tissue stains. Abbreviations: Ca, calcar; m.A, additional muscle in M. molossus; m.CC, m. calcaneocutaneous; m.D, m. depressor ossis styliformis; m. DP, m. depressor ossis styliformis profundus; m.DS, m. depressor ossis styliformis superficialis.

“Exploring the detailed muscular anatomy of very small mammals is difficult to do using dissection alone since often the details are damaged before they can be observed properly. Here, we used diceCT to learn more about the musculature associated with the bat calcar — a skeletal novelty found in bat feet. DiceCT combined with standard histology revealed anatomical variation among the calcar musculature of different bat species that quite possibly has functional implications. This could mean that the calcar has functionally diversified among bats. DiceCT is an extremely useful tool for revealing previously-unknown anatomical diversity, especially in small animals.”

 

Lead author, Kathryn Stanchak (@)

See more of this research at the Bat Cave on Twitter, the Santana Lab website, and read the the pub at The Anatomical Record!

New Publication: Specialized specialists and the narrow niche fallacy: a tale of scale-feeding fishes

 

“Lepidophagous fishes, which subsist by picking scales off other fishes, have evolved independently over 30 times. Given the seemingly specialized nature of this dietary niche, we asked the question: are all scale-feeding fishes built in a similar fashion? We used microCT to measure the feeding anatomy in a host of museum specimens, coupled with diceCT to visualize jaw musculature without marring priceless specimens with dissections. Despite living in similar habitats and feeding on presumably similar prey, lepidophagous taxa do not converge on a singular morphotype; rather, there are many ways to be a scale-feeding fish.”

– Lead author, Matt Kolmann (@)

Follow Dr. Kolmann on Twitter, and head over to Royal Society Open Science to read the open access pub!

New Publication: Dynamic Musculoskeletal Functional Morphology: Integrating diceCT and XROMM

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Select macaque hyolingual muscles. (Top) Lateral view of cranium, mandible (transparent), basihyoid, and select hyolingual muscles; (Bottom) Same view as top, showing only the muscles that are hypothesized to produce hyoid elevation. Abbreviations (color): ad, anterior digastric (yellow); bh, basihyoid (tan); gg, genioglossus (dark gray); gh, geniohyoid (blue); hg, hyoglossus (light blue); mh, mylohyoid (red); pd, posterior digastric (purple); pg, palatoglossus (pink); sg, styloglossus (green); sh, stylohyoid (orange); to, tongue (light gray). (The kinematics of these muscles were reconstructed using a combination of XROMM and FMM.)

“Studying muscle functional morphology is often easier said than done because definitively determining muscle function requires measuring many morphological and physiological parameters simultaneously. To advance our studies of the primate hyolingual apparatus, which is composed of dozens of muscles, we developed a pipeline to integrate diceCT and EMG with X-ray Reconstruction of Moving Morphology (XROMM, Brainerd et al. 2010). XROMM obtains the high spatiotemporal resolution kinematics necessary to analyze the three dimensional complexity of hyolingual movement, and incorporating diceCT provides a new method for confirming EMG electrode location and improves the accuracy of muscle and fiber length and orientation measurements. Together, these methods will help scientists to determine how organisms navigate the many ways of tuning organismal performance through musculoskeletal design.”

 

-Lead Author, Courtney Orsbon (@)

Find more methods integration at the Ross Lab website, and read the pub at The Anatomical Record!

New Publication: Comparative Anatomy of Bat Jaw Musculature via Diffusible Iodine-Based Contrast-Enhanced Computed Tomography

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DiceCT scans of a representative noctilionoid bat illustrating the 3D position of M. masseter; from left to right: 3D reconstructions of the M. masseter and the skull showing section planes; coronal sections at the posterior end of the M. masseter; oblique sections at the greatest length of the M. masseter, from diceCT scans of dissected masseters; and axial sections from diceCT scans of dissected masseters.

“Bats exhibit an outstanding diversity of cranial morphologies and diets. However, comparative studies of jaw muscle architecture have been difficult due the small size of most bats. This study used diceCT to provide, for the first time, a detailed characterization of the gross and internal anatomy of the jaw muscles across an ecologically diverse sample of bats. DiceCT allowed me to evaluate interspecific differences in muscle attachments, compartments, and scaling in the context of dietary specialization, and to provide novel anatomical descriptions within the feeding apparatus of bats. By doing so, this study revealed unexplored anatomical diversity that can inform future work in functional and evolutionary morphology.”

-Author, Sharlene Santana (@)

Following more of this research on Twitter and read the study in The Anatomical Record!

New Publication: Non-Destructive Determination of Muscle Architectural Variables Through the Use of DiceCT

 

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3D volumes and fascicular reconstructions of temporalis (top) and superficial masseter (bottom) muscles from a crab-eating macaque, using diceCT image stacks and streamline mapping in ImageXd to model individual muscle fascicles.

“Manual dissection is both inherently destructive to specimens, and reliant upon the use of sampling sites to assess muscle fascicle properties and their distribution. We present the results of a digital technique using diceCT to identify and map whole-muscle fascicle distributions within the jaw-adductor musculature of a primate specimen. Comparing these data to dissection results of the contralateral muscles, we demonstrate an ability to determine architectural variables non-invasively through the use of diceCT. Though muscle complexity may impact the convergence between traditional and digital methods, we conclude that this technique offers great potential for future work of whole-muscle mapping, whilst circumventing specimen loss.”

 

– Lead Author, Edwin Dickinson (@)

Find out more about ImageXd here and read the pub online at The Anatomical Record!

SpiceCT: Contrast Enhancement Before Your Very Eyes

“Is iodine perfusable?”

This is one of the most frequently asked questions by the diceCT community, and the Witmer Lab at Ohio University has answered: “Absolutely!”

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Comparison of diceCT- and spiceCT-imaged cormorants in frontal view—note the drastic difference in staining time for comparable soft-tissue contrast.

SpiceCT (selectively perfusable iodine-based contrast-enhanced CT) is particularly good at staining large specimens very rapidly. Iodine is perfused through the arterial system and across capillary beds, staining soft tissues nearly instantaneously and allowing for targeting regions of interest based on blood supply.

The Witmer lab recently presented their new protocol at the Society for Integrative and Comparative Biology meeting in San Francisco on 4 January 2018 and are now sharing that poster widely on FigShare. Download the poster, and add a new tool to your arsenal!

 

Thank you to authors Witmer, Porter, Cerio, Nassif, Caggiano, Griffin, and Ridgely. Find more of their work on the Witmer Lab homepage and on Twitter.

 

 

New Publication: Parallel Saltational Evolution of Ultrafast Movements in Snapping Shrimp Claws

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3D digital reconstructions of the musculature and joint mechanism in shrimp snapping claws; diceCT models alongside confocal imaging, high-speed video, and kinematic experiments helped to elucidate how the extreme performance of crustacean claws came about.

“Does dramatic functional change depend on dramatic morphological change? Kaji et al. used contrast-enhanced micro-CT and confocal imaging, high-speed video, and kinematic experiments with select 3D-printed models, to reconstruct the evolutionary changes in form and function that yielded spectacular snapping claws from simple pinching claws in two shrimp families.  They discovered that two novel claw-joint types — a slip joint and a torque-reversal joint — preceded the evolution of snapping.  They also found that the evolutionary transitions slip joint ➔ torque-reversal joint ➔ snapping occurred in both shrimp families studied.  These results show how subtle changes in joint-form yielded dramatic changes in claw function (e.g., closing speed) during the evolution of snapping claws.”

– Lead author, Tomonari Kaji (@)

See more of Dr. Kaji’s research online and head over to Current Biology to read the pub!

New Publication: 3-D mammalian tooth development using diceCT

 

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Histology (a, e), 2D diceCT sections with outlines of layers (b, f) and anterior (c, g) and apical (d, h) views of 3D models of enamel knots developing within upper canine (a–d) and lower dp3 (e–h). Scale bars = 100 μm. (See figure legend in the web version of this manuscript for interpretations of colored regions.)

“We applied the diceCT technique to image, in three dimensions, a mammalian tooth development pattern, using embryos and pouch young of the tammar wallaby (Macropus eugenii). This enabled individual tissue layers within developing teeth to be clearly distinguishable and even allowed us to image single-cell layer tissues with higher magnification sub-volume scans. Within the same scan we could 3D-visualise both the soft and hard tissues present at various stages through tooth development, including the primary and secondary dental laminae, as well as first and second generations of teeth. With these contrast-enhanced scans, we produced 3D models of in-situ tooth development, demonstrating the enormous potential to visualise this and other organogenetic patterns using this technique.”

– Authors Qamariya Nasrullah (@), Marilyn Renfree, & Alistar Evans 

Head over to the Archives of Oral Biology to read the pub and the Evans EvoMorph Lab webpage & Twitter to see more!