Table 1.
Institutional abbreviations.
Figure 1.
Original block containing new partial, semi-articulated foot of Notharctus tenebrosus AMNH 143612.
Shown here as when found in collections at American Museum of Natural History. Two views are rotated 90 degrees around a vertical axis with respect to one another. Inset on left labels some of the bones visible on the surface, indicating potential for more below. Abbreviations: Ent, entocuneiform; Mt, metatarsal; pp, proximal phalanx. Numbers refer to digit rays.
Figure 2.
Mandible of Notharctus tenebrosus AMNH 143611 associated with AMNH 143612.
Photographs are paired with voltex renderings generated from microCT scan data of this mandible. The scan was acquired at 0.05672105 millimeter resolution (cubic voxels) at the AMNH microCT scanning facility. A, Occlusal view. B, Buccal view. C, Buccal view of microCT rendering showing steps and positioning in preparation for viewing cross-sections through long-axis of mandibular symphysis. D, Series of cross-sections through mandibular symphysis, ranging from most ventral (left-most) to most dorsal (right-most), showing symphyseal fusion. E, Distal view showing spatulate nature of vertical incisors, and fused symphysis.
Figure 3.
Labeled ct reconstruction of in situ elements.
Left vs. right images are the same specimen rotated 90 degrees with respect to one another. Top vs. bottom images are rendered to show low density tufaceous matrix and to exclude it, respectively. Prior to preparation, all blocks catalogued as AMNH 143612 and AMNH 143640 were CT scanned at Stony Brook University Medical Center. The resulting images allowed us to determine which blocks contained pedal material and where it lay. Surprisingly, only two blocks (one depicted here, the same as in figure 1) contained identifiable foot material. As elements were removed, they were labeled with a unique number which is indicated for each bone visible in the bottom images. These numbers were recorded in a 3D pdf files containing images of the in situ bones, like that shown here, as physical preparation was undertaken (Appendix S2, S3). Only pedal elements have been physically removed at this time. Ribs, tibia, fibula, and fragments of an innominate remain embedded.
Figure 4.
Pedal elements after preparation.
After physical preparation of the foot was completed, all bones were scanned with microCT at resolutions ranging from 0.013–0.031 millimeter voxels. High resolution surface files were created from these images. One set of images was overlaid on the original CT scan shown in Fig. 3 to allow easier viewing and study of the in situ elements (top row). Another set of 3D surface images were articulated in a “closest packed” arrangement to get a better sense of what the foot looked like in the living animal (bottom row).
Figure 5.
Standard views of all preserved pedal elements for AMNH 143612 and AMNH 143640.
Standard views were captured in Avizo 6.3 as represented using the voltex view feature. Top rows of each element, from left to right depict lateral, plantar/volar, dorsal, and medial views. Bottom rows depict distal on the left and proximal on the right. Left most column shows bones of digit ray I, followed by ray II to the right, and so on.
Table 2.
Basic measurements of AMNH 143612 & 143640, Notharctus tenebrosus.
Figure 6.
Notharctus tenebrosus AMNH 143612-03, pedal distal phalanx of digit two.
Views are dorsal (top row), medial (second row), ventral (third row), and proximal (bottom row). Left two images are stereopair photographs. Right side images are virtual reconstructions from a microCT scan taken at 0.013 mm resolution.
Figure 7.
Notharctus tenebrosus AMNH 143612-02, pedal distal phalanx of digit three.
Views are dorsal (top row), medial (second row), ventral (third row), and proximal (bottom row). Left two images are stereopair photographs. Right side images are virtual reconstructions from a microCT scan taken at 0.013 mm resolution.
Figure 8.
Notharctus tenebrosus AMNH 143612-04, pedal distal phalanx of digit four.
Views are dorsal (top row), medial (second row), ventral (third row), and proximal (bottom row). Left two images are stereopair photographs. Right side images are virtual reconstructions from a microCT scan taken at 0.013 mm resolution.
Figure 9.
Comparison of fossil and extant distal phalanges.
MicroCT images of distal phalanges are displayed in two views: lateral (above) and dorsal (below). Fossil unguals are shown in comparison to extant specimens that bear different unguis forms: falculae (claws), grooming claws, tegulae, and ungulae (nails).
Table 3.
Basic measurements of Notharctus distal phalanges.
Figure 10.
Principle components analysis of distal phalanx morphology.
The first two components of a principal components analysis of ungual morphology are plotted. Notharctus tenebrosus specimens are represented by black dots. Specimens illustrated along the axes represent the extreme points along each axis: x axis, Nycticebus coucang (dp2) and Galeopterus variegatus; y axis, Nycticebus coucang (dp3) and Hylobates sp. Variables which are most strongly correlated with each component are also listed along the axes. See Table 3 and Materials and Methods for abbreviations and measurement descriptions.
Figure 11.
Boxplot of angle formed between distal phalanx proximal articular facet and shaft.
Facet-Shaft Angle (FSA, the angle between the two segments) is demonstrated using illustrations of specimens scaled to the same length and oriented such that the superior and inferior margins of the articular facet are within the same plane. The median specimen from each extant group is illustrated: Suricata suricatta represents the falculae group; Callithrix sp., tegulae; Hapalemur griseus, grooming claws; and Galago senegalensis, ungulae. See Materials and Methods for measurement description.
Table 4.
Principal component loadings from an analysis of distal phalanx shape.
Table 5.
ANOVAs and post hoc tests of distal phalanx variables.
Figure 12.
Boxplot of volar feature length scaled to total distal phalanx length.
Raw values of volar feature length (VFL) are divided by total phalanx length (TPL). VFL and TPL are demonstrated using illustrations of specimens scaled to the same length and oriented according to their long axes. The median specimen from each extant group is illustrated: Galeopterus vareigatus represents the falculae group; Leontopithecus sp., tegulae; Lemur catta, grooming claws; and Galago senegalensis, ungulae. See Materials and Methods for measurement descriptions.
Figure 13.
Boxplot of distal phalanx distal shaft width scaled to total phalanx length.
Raw values of shaft width taken at ¾ of the length of the shaft (SW-3/4) are divided by total phalanx length (TPL). SW-3/4 and TPL are demonstrated using illustrations of specimens scaled to the same length. The median specimen from each extant group is illustrated: Tupaia glis represents the falculae group; Callithrix sp., tegulae; Galago senegalensis, grooming claws; and Saimiri sp., ungulae. See Materials and Methods for measurement descriptions.
Figure 14.
Boxplot of ratio of distal phalanx proximal shaft height to distal shaft height.
Proximal height (SH¼) is measured at a point along the shaft of the phalanx that is ¼ of the distance from the proximal end to the tip, distal height (SH¾) at ¾ the distance. The median specimen from each extant group is illustrated: falculae - Phalanger orientalis; tegulae - Callithrix sp.; grooming phalanges - Nycticebus coucang; ungulae - Chlorocebus aethiops. See Materials and Methods for measurement descriptions.
Table 6.
T-tests comparing Notharctus distal phalanx morphology to extant primate ungular and grooming phalanges.
Figure 15.
Boxplots of pedal proportions.
Abbreviations: Pp, proximal phalanx; Mt, metatarsal. Statistical treatment of their data is given in Table 7. See Materials and Methods for further information.
Table 7.
T-tests comparing foot proportions.
Figure 16.
Plots of pp2 length/pp5 length and pp3 length/pp4.
A, Bivariate plot of pp2/pp5 length and pp3/pp4 length: closed circles (anthropoids); closed triangles (tarsiiforms); closed diamonds (lorises); open diamonds (galagos); open circles (lemuroids); closed octagon (Notharctus); closed star (Darwinius). Abbreviations: Pp, proximal phalanx; Mt, metatarsal. B, Univariate boxplots of pp2/pp5 length. C, univariate boxplots of pp3/pp4 length. Dashed lines in A and B show position of fossils relative to extant groups.
Table 8.
Analyses of proximal phalanx indices.
Table 9.
Code and coding scheme changes to matrix of Gingerich et al. [8].
Table 10.
Characters added to corrected matrix of Gingerich et al. [8].
Figure 17.
Trees resulting from analysis of corrected matrix of Gingerich et al. (2011).
A, Single most parsimonious tree including extant taxa and Darwinius only. This tree topology was produced from an exhaustive search using the corrected version of the Gingerich et al. [8] matrix (corrections noted in Table 9;see also Appendix S1, section 10 for nexus file). This topology was also produced by analysis of the corrected matrix with additional characters noted in Table 10 (see Appendix S1, section 17 for nexus file). These trees differ only in statistics such as length, CI, HI, RI, and RC. See Results. B, Single most parsimonious tree resulting from analysis of the corrected matrix with additional fossil taxa added (see SI Appendix S1, sections 14–16 for nexus files).
Figure 18.
Majority rule consensus tree of extant taxa, Darwinius, Notharctus, and Catopithecus.
Majority rule consensus tree of four equally most parsimonious trees resulting from analysis of the matrix of Gingerich et al. [8] subsequent to modifications listed in Tables 8–9, and the addition of codings for Notharctus and Catopithecus (see Appendix S1 section 4–18 for nexus files).