New light shed on the early evolution of limb-bone growth plate and bone marrow
- Department of Organismal Biology, Evolution and Development, Uppsala University, Sweden
- European Synchrotron Radiation Facility, France
- Flinders University, College of Science and Engineering, Australia
- Comenius University in Bratislava, Faculty of Natural Sciences, Department of Ecology, Slovakia
Figures
Figure 1
Schematic drawing of the long-bone epiphyses of extant amniotes (A) and amphibians (B).
Four conditions are figured here. They are separated by yellow dashed lines: A1, condition in crocodiles (interpreted from Haines, 1938); A2, condition in mammals at an early developmental stage …
Figure 2
Juvenile specimen of Apateon caducus, GPIM-N 1297.
(A) Skeleton. (a) Right limb. (B) Epiphyseal and metaphyseal histology of the proximal end of the humerus. (C) Epiphyseal and metaphyseal histology of the proximal end of the radius (c2-3) and ulna …
Figure 3
Adult specimen of Apateon caducus, GPIM-N 1572.
(A) Skeleton. (a) Right limb. (B) Epiphyseal and metaphyseal histology of the proximal end of the radius (b1) and ulna (b2). Abbreviations: c.b., cortical bone; c.m., cartilage matrix; dia., …
Figure 4
Adult specimen of Apateon pedestris, SMNS 54981.
(A) Skeleton. (a) Right limb. (B) Epiphyseal and metaphyseal histology of the distal end of the humerus. (C) Epiphyseal and metaphyseal histology of the proximal end of the radius (c2) and ulna (c1).…
Figure 5
Adult specimen of Apateon pedestris, SMNS 54988.
(A) Skeleton. (a) Right limb. (B) Epiphyseal and metaphyseal histology of the distal end of the humerus. (C) Epiphyseal and metaphyseal histology of the proximal end of the radius and ulna. …
Figure 6
Left humerus of a (sub-)adult specimen of Metoposaurus sp., MUZ PGI OS-220/171 imaged using PPC-SRµCT.
(A) Frontal view. (a1) Longitudinal virtual thin section (40 µm thick) and (a2) longitudinal virtual thin section of the segmented model of the bone (50 µm thick). The longitudinally-oriented …
Figure 7
Left humerus of a juvenile specimen of Seymouria sanjuanensis, MNG 7747 imaged using PPC-SRµCT.
(A) Frontal view. (a1) Longitudinal virtual thin section (40 µm thick), the darker part is an artefact in the original data due to electron reinjection in the synchrotron storage ring (refilling) …
Figure 8 with 1 supplement
Right humerus of an adult Seymouria sanjuanensis, CM 28597 imaged using PPC-SRµCT.
(A) Frontal view. (a1) Longitudinal virtual thin section (40 µm thick) and (a2) longitudinal section of the segmented model of the bone (450 µm thick). The longitudinally-oriented trabeculae …
Figure 8—figure supplement 1
Humeral microanatomical architecture of the stem amniote Seymouria sanjuanensis (CM 28597) and the tortoise Centrochelys sulcata.
(A) Radiography of the humerus of S. sanjuanensis in anterior view (on the left) and ventral view (on the right). The red arrows show the presence of a resting surface both in the proximal and …
Figure 9
Right humerus of a subadult Discosauriscus austriacus, SNM Z 15568 imaged using PPC-SRµCT.
Due to processing to convert the scan data into a stack of images, the images have been flipped, thereby resulting in a flipped 3D model. (A) Frontal view. (a1) Longitudinal virtual thin section (40 …
Figure 10 with 1 supplement
Longitudinal virtual sections and three-dimensional (3D) segmentation from PPC-SRµCT of marrow processes and marrow cavities in the humeral proximal ends of: A, Metoposaurus sp.
(MUZ PGI OS-220/171); B, Seymouria sanjuanensis (MNG 7747); C, S. sanjuanensis (CM 28597); D, Discosauriscus austriacus (SNM Z 15568). (a1, b1, c1, d1) Longitudinal virtual thin section (60 µm …
Figure 10—figure supplement 1
Longitudinal virtual sections and three-dimensional (3D) segmentation from PPC-SRµCT of marrow processes in the humeral proximal end of (A) Andrias sp.
(MNHN-ZA-AC-2005–72, Museum national d’Histoire naturelle, Paris, France). (a1) Longitudinal virtual thin section (60 µm thick), (a2) marrow processes segmented, (a3) 3D model of the segmentation and…
Figure 11
Evolution of growth-plate patterns and metaphyseal organisations of the long bones of the studied taxa in a phylogenetic context (e.g., Ruta and Coates, 2007; Schoch, 2019).
Hypothesis on haematopoietic activity is herein contextualised. Black silhouettes represent the taxa studied. Crosses (†) have been attributed to fossil taxa.
Figure 12
Longitudinal virtual thin sections of the right humerus of an adult Seymouria sanjuanensis (CM 28597).
(A) Tomogram showing low frequency artefacts resulting in an image divided into a darker and brighter part, (B) image processed with a filter for tomographic texture enhancement to remove low …
Tables
Table 1
Table summarising the material used.
Skull length measurements and ontogenetic stages determined by Berman et al., 1987b; Sanchez et al., 2008; Sanchez et al., 2010a and Klembara et al., 2006.
| Species | Collection number | Skull length (cm) | Ontogenetic stage | Bone |
|---|---|---|---|---|
| Apateon caducus | GPIM-N 1297 | 1.52 | Juvenile | Humerus |
| Radius | ||||
| Ulna | ||||
| GPIM-N 1572 | Estimated to 1.60 | Adult | Radius | |
| Ulna | ||||
| Apateon pedestris | SMNS 54981 | 0.86 | Adult | Humerus |
| Radius | ||||
| Ulna | ||||
| SMNS 54988 | 1.06 | Adult | Humerus | |
| Radius | ||||
| Ulna | ||||
| Seymouria sanjuanensis | MNG 7747 | 5.6 | Juvenile | Humerus |
| CM 28597 | 8.8 | Adult | Humerus | |
| Discosauriscus austriacus | SNM Z 15568 | 6.2 | Subadult | Humerus |
| Metoposaurus sp. | MUZ PGI OS-220/171 | - | Subadult or adult | Humerus |
Table 2
Microanatomical measurements made on the samples using VGStudio MAX (version 3.2, Volume Graphics Inc, Germany).
The protocol details are provided by Estefa et al., 2020.
| Species | Thickness of the trabeculae (µm) | Diameter of the marrow processes (µm) | |
|---|---|---|---|
| Diaphysis | Metaphysis | Metaphysis | |
| Metoposaurus sp. (Subadult or Adult, MUZ PGI OS-220/171) | 131 | 117 | 248 |
| Seymouria sanjuanensis (Juvenile, MNG 7747) | 94 | 25 | 100 |
| S. sanjuanensis (Adult, CM 28597) | 79 | 30 | 100 |
| Discosauriscus austriacus (Subadult, SNM Z 15568) | 80 | 54 | 111 |
