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Dryad

Conserved patterns and locomotor-related evolutionary constraints in the hominoid vertebral column

Cite this dataset

Villamil, Catalina I.; Middleton, Emily R. (2024). Conserved patterns and locomotor-related evolutionary constraints in the hominoid vertebral column [Dataset]. Dryad. https://doi.org/10.5061/dryad.v6wwpzh17

Abstract

The evolution of the hominoid lineage is characterized by pervasive homoplasy, notably in regions such as the vertebral column, which plays a central role in body support and locomotion. Few isolated and fewer associated vertebrae are known for most fossil hominoid taxa, but identified specimens indicate potentially high levels of convergence in terms of both form and number. Homoplasy thus complicates attempts to identify the anatomy of the last common ancestor of hominins and other taxa and stymies reconstructions of evolutionary scenarios. One way to clarify the role of homoplasy is by investigating constraints via phenotypic integration, which assesses covariation among traits, shapes evolutionary pathways, and itself evolves in response to selection. We assessed phenotypic integration and evolvability across the subaxial (cervical, thoracic, lumbar, sacral) vertebral column of macaques (n = 96), gibbons (n = 77), chimpanzees (n = 92), and modern humans (n = 151). We found a mid-cervical cluster that may have shifted cranially in hominoids, a persistent thoracic cluster that is most marked in chimpanzees, and an expanded lumbosacral cluster in hominoids that is most expanded in gibbons. Our results highlight the highly conserved nature of the vertebral column. Taxa appear to exploit existing patterns of integration and ontogenetic processes to shift, expand, or reduce cluster boundaries. Gibbons appear to be the most highly derived taxon in our sample, possibly in response to their highly specialized locomotion.

README: Conserved patterns and locomotor-related evolutionary constraints in the hominoid vertebral column

Catalina I. Villamil, Emily R. Middleton

We include four separate files, one for each taxon: homo.csv, pan.csv, hylobates.csv, macaca.csv

Data are provided in CSV files with each row representing one individual. Data are organized by column.

All taxa have 7 cervical elements modally. The modal formula for Homo is 12 thoracic, 5 lumbar, and 5 sacral (12T:5L:5S) elements, for Pan is 13T:4L:6S, for Hylobates is 13T:5L:4S, and for Macaca is 12T:7L:3S. Vertebral IDs for individuals with nonmodal formulae have been adjusted as follows:

  • We removed T7 from analyses for individuals with an extra thoracic segment, and moved subsequent thoracic vertebrae up in the sequence (T8 treated as T7, T9 treated as T8, etc.)
  • We treated T7 as missing for individuals with fewer than the modal number of thoracic elements and moved subsequent elements down in nthe sequeence (T7 treated as T8, T8 treated as T9, etc.)
  • We removed L3 (in Hylobates) or L4 (in Macaca) for individuals with an extra lumbar segment and moved subsequent vertebrae up in the sequence (L5 treated as L4, etc.).
  • We treated L2 as missing in individuals with fewer than modal lumbar segments and moved subsequent elements down in the sequence (L3 treated as L4, etc.). This occurred only in Pan.
  • No adjustments were made to variation in sacral element number.

Human data from the British Museum are anonymized. Human data from the Galloway Collection (Makerere University, College of Health Sciences) and Dart Collection (University of Witwatersrand), which were included in the associated manuscript, are excluded to align with those institution's policies.

Please refer to the associated manuscript for more detailed descriptions of each measurement.

Each measurement name is listed with the element name/number first, as described below:
C+NUMBER Cervical + position (1 through 7, e.g. C3)
T+NUMBER Thoracic + position (1 through 12 or 13, e.g. T9)
L+NUMBER Lumbar + position (1 through 4, 5, or 7, e.g. L3)
S Sacral (whole sacrum)
S1 First sacral element

In the following key, 'vert' stands for each element name/number as described above.

Measurement key:

  • vert_SPINE Spine length, measured cranially from the margin of the laminae to the tip of the spine with the calipers parallel to the spine
  • vert_PREZ Pre-zygapophyseal (cranial articular facets) breadth, measured from the two most lateral points of the pre-zygapophyses
  • vert_POSTZ Post-zygapophyseal (caudal articular facets) breadth, measured from the two most lateral points of the post-zygapophyses
  • vert_PREZPOSTZ Interzygous height, measured from most cranial point of the pre-zygapophysis to the most caudal point of the post-zygapophysis
  • vert_BODY_HEIGHT Ventral craniocaudal body height, measured at midline
  • vert_BODY_BREADTH Caudal transverse body breadth, measured at the greatest breadth
  • vert_BODY_WIDTH Caudal dorsoventral body width, measured at the midline
  • vert_MAX_AUB Maximum transverse breadth at ventral projections of the auricular surfaces
  • vert_CAUD_AU Transverse breadth at the caudal margin of the auricular surface
  • vert_VENTL Ventral length, measured from the midpoint of the promotory of S1 to the midpoint of the most caudal/distal sacral element
  • vert_CCH Craniocaudal height of first sacral element, measured at the ventral midline

ANONID indicates the anonymized ID number for that individual (humans/Homo)
MUSID indicates the museum catalogue number (all other taxa)

Institutions:
CPRCMUS Caribbean Primate Research Center Museum, San Juan, PR, USA
MCZ Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA
AMNH American Museum of Natural History, New York, NY, USA
HTB Hamann-Todd Osteological Collection, Cleveland Museum of Natural History, Cleveland, OH, USA
Powell-Cotton Powell-Cotton Museum, Birchington-on-Sea, England, UK
RG Royal Museum of Central Africa, Tervuren, Belgium
USNM Smithsonian Museum of Natural History (US National Museums), Washington DC, USA

Sex:
F Female
M Male
U Unknown

Methods

This dataset includes linear data from the subaxial vertebral column (cervical, thoracic, lumbar, and sacral) of 96 Macaca mulatta, 76 Hylobates lar, 92 Pan troglodytes, and 29 Homo sapiens individuals. 

Data were collected using a Mitutoyo Digital Caliper accurate to 0.02 mm and are reported in millimeters (mm). "." is used to denote a decimal throughout. Raw linear data are provided for all available elements for each individual. Missing data is noted with 'NA' and indicates the element or trait was missing. Intraobserver error ranges between 1.06-1.28%. 

Not all individuals display the modal formula for that taxon. Vertebral IDs have been adjusted as described in the associated manuscript and README file.

Human data from the British Museum are anonymized.

Usage notes

Files are uploaded as .CSV files.

Funding

Wenner-Gren Foundation, Award: 9110

Wenner-Gren Foundation, Award: 9770

Office of Research Infrastructure Programs, Award: 2-P40- OD012217

American Association for Anatomy

New York University

Leakey Foundation