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Zheng X, Bailleul AM, Li Z, Wang X, Zhou Z. Nuclear preservation in the cartilage of the Jehol dinosaur Caudipteryx. Commun Biol 2021; 4:1125. [PMID: 34561538 PMCID: PMC8463611 DOI: 10.1038/s42003-021-02627-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 08/31/2021] [Indexed: 11/23/2022] Open
Abstract
Previous findings on dinosaur cartilage material from the Late Cretaceous of Montana suggested that cartilage is a vertebrate tissue with unique characteristics that favor nuclear preservation. Here, we analyze additional dinosaur cartilage in Caudipteryx (STM4-3) from the Early Cretaceous Jehol biota of Northeast China. The cartilage fragment is highly diagenetically altered when observed in ground-sections but shows exquisite preservation after demineralization. It reveals transparent, alumino-silicified chondrocytes and brown, ironized chondrocytes. The histochemical stain Hematoxylin and Eosin (that stains the nucleus and cytoplasm in extant cells) was applied to both the demineralized cartilage of Caudipteryx and that of a chicken. The two specimens reacted identically, and one dinosaur chondrocyte revealed a nucleus with fossilized threads of chromatin. This is the second example of fossilized chromatin threads in a vertebrate material. These data show that some of the original nuclear biochemistry is preserved in this dinosaur cartilage material and further support the hypothesis that cartilage is very prone to nuclear fossilization and a perfect candidate to further understand DNA preservation in deep time.
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Affiliation(s)
- Xiaoting Zheng
- Institute of Geology and Paleontology, Linyi University, Linyi City, Shandong, 276005, China
- Shandong Tianyu Museum of Nature, Pingyi, Shandong, 273300, China
| | - Alida M Bailleul
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, 142 Xizhimenwai dajie, Beijing, 100044, China.
- CAS Center for Excellence in Life and Paleoenvironment, Beijing, 100044, China.
| | - Zhiheng Li
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, 142 Xizhimenwai dajie, Beijing, 100044, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing, 100044, China
| | - Xiaoli Wang
- Institute of Geology and Paleontology, Linyi University, Linyi City, Shandong, 276005, China
- Shandong Tianyu Museum of Nature, Pingyi, Shandong, 273300, China
| | - Zhonghe Zhou
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, 142 Xizhimenwai dajie, Beijing, 100044, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing, 100044, China
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Bailleul AM, Lu J, Li Z. DiceCT applied to fossilized hard tissues: A preliminary case study using a miocene bird. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2021; 336:364-375. [PMID: 33666331 DOI: 10.1002/jez.b.23037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/02/2021] [Accepted: 02/14/2021] [Indexed: 11/12/2022]
Abstract
Iodine-based contrasting agents for computed tomography (CT) have been used for decades in medicine. Agents like Lugol's iodine enhance the contrasts between soft tissues and mineralized (skeletal) tissues. Because a recent study on extant avian heads showed that iodine-ethanol (I2 E) is a better contrast enhancer overall than the standard Lugol's iodine, here, we tested if I2 E could also enhance the CT contrasts of two fossilized skeletal tissues: bone and calcified cartilage. For this, we used a partial ankle joint from an extinct pheasant from the Late Miocene of Northwest China (Linxia Basin). The pre-staining CT scans showed no microstructural details of the sample. After being immersed into a solution of 1% I2 E for 8 days and scanned a second time, the contrasts were drastically enhanced between the mineralized tissues (bony trabeculae and calcified cartilage) and the sediments and minerals inside vascular spaces. After three other staining-scanning cycles in 2%, 3%, and 6% I2 E solutions, the best contrasts were obtained after immersion in 6% I2 E for 7 days. Energy Dispersive Spectroscopy showed that iodine was preferentially absorbed by the mineralized tissues and the minerals in the vascular spaces, but not by the sediments. This method not only effectively increased the contrasts of two different fossilized skeletal tissues, it was also non-destructive and reversible because part of the fossil was successfully de-stained after a few days in pure ethanol. These preliminary results indicate that iodine-ethanol has the potential to be used widely in vertebrate paleontology to improve CT imaging of fossilized tissues.
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Affiliation(s)
- Alida M Bailleul
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China.,CAS Center for Excellence in Life and Paleoenvironment, Beijing, China
| | - Jing Lu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China.,CAS Center for Excellence in Life and Paleoenvironment, Beijing, China
| | - Zhiheng Li
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China.,CAS Center for Excellence in Life and Paleoenvironment, Beijing, China
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Bell A, Chiappe LM. Anatomy of Parahesperornis: Evolutionary Mosaicism in the Cretaceous Hesperornithiformes (Aves). Life (Basel) 2020; 10:life10050062. [PMID: 32422986 PMCID: PMC7281208 DOI: 10.3390/life10050062] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/09/2020] [Accepted: 05/11/2020] [Indexed: 12/21/2022] Open
Abstract
The Hesperornithiformes constitute the first known avian lineage to secondarily lose flight in exchange for the evolution of a highly derived foot-propelled diving lifestyle, thus representing the first lineage of truly aquatic birds. First unearthed in the 19th century, and today known from numerous Late Cretaceous (Cenomanian-Maastrichtian) sites distributed across the northern hemisphere, these toothed birds have become icons of early avian evolution. Initially erected as a taxon in 1984 by L. D. Martin, Parahesperornis alexi is known from the two most complete hesperornithiform specimens discovered to date and has yet to be fully described. P. alexi thus contributes significantly to our understanding of hesperornithiform birds, despite often being neglected in favor of the iconic Hesperornis. Here, we present a full anatomical description of P. alexi based upon the two nearly complete specimens in the collections of the University of Kansas Natural History Museum, as well as an extensive comparison to other hesperornithiform taxa. This study reveals P. alexi to possess a mosaic of basal and derived traits found among other hesperornithiform taxa, indicating a transitional form in the evolution of these foot-propelled diving birds. This study describes broad evolutionary patterns within the Hesperornithiformes, highlighting the significance of these birds as not only an incredible example of the evolution of ecological specializations, but also for understanding modern bird evolution, as they are the last known divergence of pre-modern bird diversification.
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Hummingbird-sized dinosaur from the Cretaceous period of Myanmar. Nature 2020; 579:245-249. [PMID: 32161388 DOI: 10.1038/s41586-020-2068-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/22/2020] [Indexed: 11/08/2022]
Abstract
Skeletal inclusions in approximately 99-million-year-old amber from northern Myanmar provide unprecedented insights into the soft tissue and skeletal anatomy of minute fauna, which are not typically preserved in other depositional environments1-3. Among a diversity of vertebrates, seven specimens that preserve the skeletal remains of enantiornithine birds have previously been described1,4-8, all of which (including at least one seemingly mature specimen) are smaller than specimens recovered from lithic materials. Here we describe an exceptionally well-preserved and diminutive bird-like skull that documents a new species, which we name Oculudentavis khaungraae gen. et sp. nov. The find appears to represent the smallest known dinosaur of the Mesozoic era, rivalling the bee hummingbird (Mellisuga helenae)-the smallest living bird-in size. The O. khaungraae specimen preserves features that hint at miniaturization constraints, including a unique pattern of cranial fusion and an autapomorphic ocular morphology9 that resembles the eyes of lizards. The conically arranged scleral ossicles define a small pupil, indicative of diurnal activity. Miniaturization most commonly arises in isolated environments, and the diminutive size of Oculudentavis is therefore consistent with previous suggestions that this amber formed on an island within the Trans-Tethyan arc10. The size and morphology of this species suggest a previously unknown bauplan, and a previously undetected ecology. This discovery highlights the potential of amber deposits to reveal the lowest limits of vertebrate body size.
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Bailleul AM, Zheng W, Horner JR, Hall BK, Holliday CM, Schweitzer MH. Evidence of proteins, chromosomes and chemical markers of DNA in exceptionally preserved dinosaur cartilage. Natl Sci Rev 2020; 7:815-822. [PMID: 34692099 PMCID: PMC8289162 DOI: 10.1093/nsr/nwz206] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 01/13/2023] Open
Abstract
A histological ground-section from a duck-billed dinosaur nestling (Hypacrosaurus stebingeri) revealed microstructures morphologically consistent with nuclei and chromosomes in cells within calcified cartilage. We hypothesized that this exceptional cellular preservation extended to the molecular level and had molecular features in common with extant avian cartilage. Histochemical and immunological evidence supports in situ preservation of extracellular matrix components found in extant cartilage, including glycosaminoglycans and collagen type II. Furthermore, isolated Hypacrosaurus chondrocytes react positively with two DNA intercalating stains. Specific DNA staining is only observed inside the isolated cells, suggesting endogenous nuclear material survived fossilization. Our data support the hypothesis that calcified cartilage is preserved at the molecular level in this Mesozoic material, and suggest that remnants of once-living chondrocytes, including their DNA, may preserve for millions of years.
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Affiliation(s)
- Alida M Bailleul
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
| | - Wenxia Zheng
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - John R Horner
- Honors Program, Chapman University, Orange, CA 92866, USA
| | - Brian K Hall
- Department of Biology, Dalhousie University, Halifax, B3H 4R2, Canada
| | - Casey M Holliday
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Mary H Schweitzer
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
- North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA
- Department of Geology, University of Lund, 22362, Sweden
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