Papers by Lauren Halenar-Price
American Journal of Physical Anthropology, 2019
Objectives: Fossils have been linked to Alouatta based on shared cranial morphology and small bra... more Objectives: Fossils have been linked to Alouatta based on shared cranial morphology and small brain size. However, the relationship between endocranial volume and cranial shape is unclear; it is possible that any platyrrhine with a small brain may exhibit "Alouatta-like" features due to being "de-encephalized." We test two hypotheses: (a) there are aspects of cranial shape related to encephalization common to all platyrrhines; (b) it is these cranial traits that unite the small-brained "Alouatta-like" fossils. Materials and methods: Three-dimensional cranial shape and endocranial volume (ECV) were measured on 350+ extant platyrrhine crania, Cartelles, Paralouatta, and Antillothrix. Encephaliza-tion quotient (EQ) was calculated using regressions of ECV on cranial centroid size. Multivariate regressions were performed using the shape coordinates and EQ and shape changes associated with EQ were visualized. Cranial shape was predicted for a hypothetical primate with an EQ matching the fossils and this shape was compared to the Alouatta mean. Results: There is a significant proportion of cranial shape variation explained by EQ in some taxa. The aspects of shape that are correlated with EQ are shared by several taxa and some have parallel regression vectors, but there is no overall pattern of shape change common to all platyrrhines. However, all taxa look more similar to Alouatta when their EQ is decreased, particularly Pithecia. Discussion: Given that a decrease in encephalization can cause a more Alouatta-like cranial shape in many extant platyrrhines, it should not be automatically assumed that Alouatta-like cranial traits in a small-brained fossil are evidence of a phylogenetic link to the alouattin clade. K E Y W O R D S
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Recent paleontological collection in submerged caves in the eastern Dominican Republic has yielde... more Recent paleontological collection in submerged caves in the eastern Dominican Republic has yielded new specimens of Antillothrix bernensis. Here we describe a complete cranium of an adult individual (MHD 20) and provide phenetic comparisons to other endemic Caribbean taxa and extant mainland platyrrhines using three-dimensional geometric morphometric methods (3DGM). Qualitative and quantitative comparisons support conclusions based on other recently described fossil material: Antillothrix has a dentition lacking clear dietary specialization, an elongated brain case with strong temporal lines, and a vertically oriented nuchal plane. MHD 20 shares a combination of traits with a previously published subadult specimen (MHD 01) including a deep depression at glabella, dorsoventrally elongated orbits, and a relatively large face. This shared morphology reinforces the taxonomic affinity of the two specimens , with differences between the two likely reflecting the younger ontogenetic age of MHD 01. Comparisons to the extant platyrrhines paint a complicated picture as the results of between-group principal components analyses (bgPCA) indicate that Antillothrix does not share a suite of morphological features exclusively with any one genus. Depending on which bgPC axes are visualized, and which subset of landmarks is included (i.e., only those describing the shape of the face/palate for inclusion of Xenothrix), MHD 20 is most similar in shape to the atelids, Alouatta, Lagothrix, and Brachyteles, or an otherwise " empty " region of shape space. It groups neither with Cebus nor Callicebus, two taxa that Antillothrix has been associated with in previous studies based on much less complete material. The Antillothrix cranium does not exhibit any of the derived characters classically used to diagnose or define any single clade; rather its morphology shares features with multiple platyrrhine groups. This is consistent with the interpretation that Antillothrix preserves a primitive morphology, which accords with the hypothesis positing an early arrival of platyrrhines in the Caribbean.
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The Anatomical Record: Advances in Integrative …, Jan 1, 2011
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The Anatomical Record: Advances in Integrative …, Jan 1, 2011
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The Anatomical Record: …, Jan 1, 2011
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Recent paleontological collection in submerged caves in the eastern Dominican Republic has yielde... more Recent paleontological collection in submerged caves in the eastern Dominican Republic has yielded new specimens of Antillothrix bernensis. Here we describe a complete cranium of an adult individual (MHD 20) and provide phenetic comparisons to other endemic Caribbean taxa and extant mainland platyrrhines using three-dimensional geometric morphometric methods (3DGM). Qualitative and quantitative comparisons support conclusions based on other recently described fossil material: Antillothrix has a dentition lacking clear dietary specialization, an elongated brain case with strong temporal lines, and a vertically oriented nuchal plane. MHD 20 shares a combination of traits with a previously published subadult specimen (MHD 01) including a deep depression at glabella, dorsoventrally elongated orbits, and a relatively large face. This shared morphology reinforces the taxonomic affinity of the two specimens , with differences between the two likely reflecting the younger ontogenetic age of MHD 01. Comparisons to the extant platyrrhines paint a complicated picture as the results of between-group principal components analyses (bgPCA) indicate that Antillothrix does not share a suite of morphological features exclusively with any one genus. Depending on which bgPC axes are visualized, and which subset of landmarks is included (i.e., only those describing the shape of the face/palate for inclusion of Xenothrix), MHD 20 is most similar in shape to the atelids, Alouatta, Lagothrix, and Brachyteles, or an otherwise "empty" region of shape space. It groups neither with Cebus nor Callicebus, two taxa that Antillothrix has been associated with in previous studies based on much less complete material. The Antillothrix cranium does not exhibit any of the derived characters classically used to diagnose or define any single clade; rather its morphology shares features with multiple platyrrhine groups. This is consistent with the interpretation that Antillothrix preserves a primitive morphology, which accords with the hypothesis positing an early arrival of platyrrhines in the Caribbean.
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In this study, we assess the precision, accuracy, and repeatability of craniodental landmarks (Ty... more In this study, we assess the precision, accuracy, and repeatability of craniodental landmarks (Types I, II, and III, plus curves of semilandmarks) on a single macaque cranium digitally reconstructed with three different surface scanners and a microCT scanner. Nine researchers with varying degrees of osteological and geometric morphometric knowledge land-marked ten iterations of each scan (40 total) to test the effects of scan quality, researcher experience, and landmark type on levels of intra-and interobserver error. Two researchers additionally landmarked ten specimens from seven different macaque species using the same landmark protocol to test the effects of the previously listed variables relative to species level morphological differences (i.e., observer variance versus real biological variance). Error rates within and among researchers by scan type were calculated to determine whether or not data collected by different individuals or on different digitally rendered crania are consistent enough to be used in a single dataset. Results indicate that scan type does not impact rate of intra-or interobserver error. Interobserver error is far greater than intraob-server error among all individuals, and is similar in variance to that found among different macaque species. Additionally, experience with osteology and morphometrics both positively contribute to precision in multiple landmarking sessions, even where less experienced researchers have been trained in point acquisition. Individual training increases precision (although not necessarily accuracy), and is highly recommended in any situation where multiple researchers will be collecting data for a single project. PLOS ONE | https://doi.org/10.1371/journal.pone.
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Anatomical Record, 2011
"Among living New World monkeys, Howlers and Muriquis are by far
the most folivorous. We examine... more "Among living New World monkeys, Howlers and Muriquis are by far
the most folivorous. We examine how well the morphology and behavior of
Alouatta and Brachyteles conform to leaf-eating adaptational models
derived from other studies. Both genera match these expectations
unevenly, which suggests a broader conception of primate folivory is in
order. Hence the notion of ‘‘semifolivory.’’ While their dentitions prove
highly sensitive to selection for leaf-eating, core features relating to body
size, brain size, ranging behavior and presumed energy budgets are less
predictable corollaries. Leaf-eating in atelines and colobines may have
evolved from a preadaptive reliance on seed-eating, which would have
necessitated comparable gastric adaptations. Fossils suggest semifolivory
in the low-energy Howler lineage may have begun with an increase in
body size, a relatively small brain and, possibly, a concomitantly enlarged
gut, followed by dental adaptations. It may have advanced via body-size
reduction, part of a pioneering adaptation in marginal ecologies on the
periphery of rich Amazonian habitats or as a strategy to minimize
competition among an abundance of frugivores within the lowland forest—
perhaps not as a fallback scheme. In the high-energy Muriqui, semifolivory
may have evolved in more intensely seasonal, low-yield forests where
frugivores were constrained and rare, a model more consistent with the
fallback paradigm. The seed-to-leaves evolutionary pathway hypothesized
for anthropoid leaf-eaters may be a widespread phenomenon in primates.
We propose it is ultimately rooted in a pre-euprimate reliance on the seeds
and seed coats of primitive angiosperms before the latter evolved attractive
sugary fruits to coax primates into becoming dispersers of seeds, instead
consumers."
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Book Chapters by Lauren Halenar-Price
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Phylogeny, Molecular Population Genetics, 2016
The extant radiation of Neotropical primates, the platyrrhines, occupy
a great variety of ecologi... more The extant radiation of Neotropical primates, the platyrrhines, occupy
a great variety of ecological niches in the tropical forests of Central and
South America. This diversity includes large-bodied suspensory ripe fruit
specialists such as Ateles, mid-canopy dwelling seed consuming pitheciids,
the predominantly folivorous genera Alouatta and Brachyteles, the very
small-bodied insect- and sap-consuming pygmy marmoset as well as the
only nocturnal anthropoid, Aotus or the Owl Monkey, among many others.
Though this radiation is incredibly diverse today, at the terminal
Pleistocene, there were several species unlike any extant forms; these
included the very large-bodied (20 kg) Brazilian atelids and several species
of endemic Caribbean primates with unique morphological adaptations. In
this chapter, we review the history of the discovery of the Brazilian and
Caribbean extinct primates, discuss their major morphological adaptations
including their unique cranial, postcranial, and dental morphologies, and
review possible extinction scenarios. Though the exact timing of their
extinction is unclear, these primates seem to have disappeared from their
respective environments after the arrival of human beings. Finally, we
discuss the ecological impact that these extinctions may have had and the
ways that paleontologists can contribute to understanding extinction
processes today.
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Howler Monkeys, 2014
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Springer Science+Business Media New York 2015 133 M.M. Kowalewski et al. (eds.), Howler Monkeys, Developments in Primatology: Progress and Prospects, 2015
Recognition of a particularly derived eco-behavioral strategy for the
genus Alouatta has been cru... more Recognition of a particularly derived eco-behavioral strategy for the
genus Alouatta has been crucial for studying and understanding its equally derived
cranial and postcranial morphology. The unique architecture of the skull and mandible
has very likely evolved in relation to both masticatory correlates associated
with an increasingly folivorous diet as well as the use of vocal communication associated
with social behavior and an energy-minimizing strategy. Comparisons of cranial
morphology using three-dimensional geometric morphometrics have
highlighted signifi cant interspecifi c shape differences. Alouatta seniculus is the
most divergent in both cranial and hyoid morphology and exhibits the most pronounced
levels of sexual dimorphism in those areas. Cranial variability is expressed
in facial prognathism and airorhynchy, basicranial fl exure, and zygomatic height.
Inter- and intraspecifi c differences based on these axes of variation are very likely
linked to interspecifi c variations in diet, behavior, and life history. This is further
evident in the dental anatomy of the genus, indicating adaptations to a shift to a
more folivorous diet. In addition, recent studies provide further evidence for signifi -
cant inter- and intraspecifi c variations in hyoid size and shape. Alouatta seniculus
possesses the largest and most infl ated hyoid bulla, and the species that occupy distributional
extremes ( A. palliata , A. caraya ) are differentiated by highly distinct hyoid
shapes. These data indicate a complex relationship between morphology and behavior,
with possible biogeographic implications. In terms of postcranial morphology,the forelimb bears a mixture of features that favor quadrupedalism with restricted
abduction and overhead extension, providing stable contact and support along
branches. In contrast, the hind limb appears to allow for a wider range of movement
in all joints, with an emphasis on thigh extension and abduction, leg rotation, and
powerful grasping with a habitually inverted foot. Interspecifi c variation reveals
traits that can be ultimately related to subtle differences in the frequency of use of
different positional modes, associated with variable eco-social factors. These
results, deriving from different anatomical regions, provide evidence for understanding
morphological variation across howler species in terms of morphofunctional
adaptations, environmental pressure, and niche partitioning.
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Papers by Lauren Halenar-Price
the most folivorous. We examine how well the morphology and behavior of
Alouatta and Brachyteles conform to leaf-eating adaptational models
derived from other studies. Both genera match these expectations
unevenly, which suggests a broader conception of primate folivory is in
order. Hence the notion of ‘‘semifolivory.’’ While their dentitions prove
highly sensitive to selection for leaf-eating, core features relating to body
size, brain size, ranging behavior and presumed energy budgets are less
predictable corollaries. Leaf-eating in atelines and colobines may have
evolved from a preadaptive reliance on seed-eating, which would have
necessitated comparable gastric adaptations. Fossils suggest semifolivory
in the low-energy Howler lineage may have begun with an increase in
body size, a relatively small brain and, possibly, a concomitantly enlarged
gut, followed by dental adaptations. It may have advanced via body-size
reduction, part of a pioneering adaptation in marginal ecologies on the
periphery of rich Amazonian habitats or as a strategy to minimize
competition among an abundance of frugivores within the lowland forest—
perhaps not as a fallback scheme. In the high-energy Muriqui, semifolivory
may have evolved in more intensely seasonal, low-yield forests where
frugivores were constrained and rare, a model more consistent with the
fallback paradigm. The seed-to-leaves evolutionary pathway hypothesized
for anthropoid leaf-eaters may be a widespread phenomenon in primates.
We propose it is ultimately rooted in a pre-euprimate reliance on the seeds
and seed coats of primitive angiosperms before the latter evolved attractive
sugary fruits to coax primates into becoming dispersers of seeds, instead
consumers."
Book Chapters by Lauren Halenar-Price
a great variety of ecological niches in the tropical forests of Central and
South America. This diversity includes large-bodied suspensory ripe fruit
specialists such as Ateles, mid-canopy dwelling seed consuming pitheciids,
the predominantly folivorous genera Alouatta and Brachyteles, the very
small-bodied insect- and sap-consuming pygmy marmoset as well as the
only nocturnal anthropoid, Aotus or the Owl Monkey, among many others.
Though this radiation is incredibly diverse today, at the terminal
Pleistocene, there were several species unlike any extant forms; these
included the very large-bodied (20 kg) Brazilian atelids and several species
of endemic Caribbean primates with unique morphological adaptations. In
this chapter, we review the history of the discovery of the Brazilian and
Caribbean extinct primates, discuss their major morphological adaptations
including their unique cranial, postcranial, and dental morphologies, and
review possible extinction scenarios. Though the exact timing of their
extinction is unclear, these primates seem to have disappeared from their
respective environments after the arrival of human beings. Finally, we
discuss the ecological impact that these extinctions may have had and the
ways that paleontologists can contribute to understanding extinction
processes today.
genus Alouatta has been crucial for studying and understanding its equally derived
cranial and postcranial morphology. The unique architecture of the skull and mandible
has very likely evolved in relation to both masticatory correlates associated
with an increasingly folivorous diet as well as the use of vocal communication associated
with social behavior and an energy-minimizing strategy. Comparisons of cranial
morphology using three-dimensional geometric morphometrics have
highlighted signifi cant interspecifi c shape differences. Alouatta seniculus is the
most divergent in both cranial and hyoid morphology and exhibits the most pronounced
levels of sexual dimorphism in those areas. Cranial variability is expressed
in facial prognathism and airorhynchy, basicranial fl exure, and zygomatic height.
Inter- and intraspecifi c differences based on these axes of variation are very likely
linked to interspecifi c variations in diet, behavior, and life history. This is further
evident in the dental anatomy of the genus, indicating adaptations to a shift to a
more folivorous diet. In addition, recent studies provide further evidence for signifi -
cant inter- and intraspecifi c variations in hyoid size and shape. Alouatta seniculus
possesses the largest and most infl ated hyoid bulla, and the species that occupy distributional
extremes ( A. palliata , A. caraya ) are differentiated by highly distinct hyoid
shapes. These data indicate a complex relationship between morphology and behavior,
with possible biogeographic implications. In terms of postcranial morphology,the forelimb bears a mixture of features that favor quadrupedalism with restricted
abduction and overhead extension, providing stable contact and support along
branches. In contrast, the hind limb appears to allow for a wider range of movement
in all joints, with an emphasis on thigh extension and abduction, leg rotation, and
powerful grasping with a habitually inverted foot. Interspecifi c variation reveals
traits that can be ultimately related to subtle differences in the frequency of use of
different positional modes, associated with variable eco-social factors. These
results, deriving from different anatomical regions, provide evidence for understanding
morphological variation across howler species in terms of morphofunctional
adaptations, environmental pressure, and niche partitioning.
the most folivorous. We examine how well the morphology and behavior of
Alouatta and Brachyteles conform to leaf-eating adaptational models
derived from other studies. Both genera match these expectations
unevenly, which suggests a broader conception of primate folivory is in
order. Hence the notion of ‘‘semifolivory.’’ While their dentitions prove
highly sensitive to selection for leaf-eating, core features relating to body
size, brain size, ranging behavior and presumed energy budgets are less
predictable corollaries. Leaf-eating in atelines and colobines may have
evolved from a preadaptive reliance on seed-eating, which would have
necessitated comparable gastric adaptations. Fossils suggest semifolivory
in the low-energy Howler lineage may have begun with an increase in
body size, a relatively small brain and, possibly, a concomitantly enlarged
gut, followed by dental adaptations. It may have advanced via body-size
reduction, part of a pioneering adaptation in marginal ecologies on the
periphery of rich Amazonian habitats or as a strategy to minimize
competition among an abundance of frugivores within the lowland forest—
perhaps not as a fallback scheme. In the high-energy Muriqui, semifolivory
may have evolved in more intensely seasonal, low-yield forests where
frugivores were constrained and rare, a model more consistent with the
fallback paradigm. The seed-to-leaves evolutionary pathway hypothesized
for anthropoid leaf-eaters may be a widespread phenomenon in primates.
We propose it is ultimately rooted in a pre-euprimate reliance on the seeds
and seed coats of primitive angiosperms before the latter evolved attractive
sugary fruits to coax primates into becoming dispersers of seeds, instead
consumers."
a great variety of ecological niches in the tropical forests of Central and
South America. This diversity includes large-bodied suspensory ripe fruit
specialists such as Ateles, mid-canopy dwelling seed consuming pitheciids,
the predominantly folivorous genera Alouatta and Brachyteles, the very
small-bodied insect- and sap-consuming pygmy marmoset as well as the
only nocturnal anthropoid, Aotus or the Owl Monkey, among many others.
Though this radiation is incredibly diverse today, at the terminal
Pleistocene, there were several species unlike any extant forms; these
included the very large-bodied (20 kg) Brazilian atelids and several species
of endemic Caribbean primates with unique morphological adaptations. In
this chapter, we review the history of the discovery of the Brazilian and
Caribbean extinct primates, discuss their major morphological adaptations
including their unique cranial, postcranial, and dental morphologies, and
review possible extinction scenarios. Though the exact timing of their
extinction is unclear, these primates seem to have disappeared from their
respective environments after the arrival of human beings. Finally, we
discuss the ecological impact that these extinctions may have had and the
ways that paleontologists can contribute to understanding extinction
processes today.
genus Alouatta has been crucial for studying and understanding its equally derived
cranial and postcranial morphology. The unique architecture of the skull and mandible
has very likely evolved in relation to both masticatory correlates associated
with an increasingly folivorous diet as well as the use of vocal communication associated
with social behavior and an energy-minimizing strategy. Comparisons of cranial
morphology using three-dimensional geometric morphometrics have
highlighted signifi cant interspecifi c shape differences. Alouatta seniculus is the
most divergent in both cranial and hyoid morphology and exhibits the most pronounced
levels of sexual dimorphism in those areas. Cranial variability is expressed
in facial prognathism and airorhynchy, basicranial fl exure, and zygomatic height.
Inter- and intraspecifi c differences based on these axes of variation are very likely
linked to interspecifi c variations in diet, behavior, and life history. This is further
evident in the dental anatomy of the genus, indicating adaptations to a shift to a
more folivorous diet. In addition, recent studies provide further evidence for signifi -
cant inter- and intraspecifi c variations in hyoid size and shape. Alouatta seniculus
possesses the largest and most infl ated hyoid bulla, and the species that occupy distributional
extremes ( A. palliata , A. caraya ) are differentiated by highly distinct hyoid
shapes. These data indicate a complex relationship between morphology and behavior,
with possible biogeographic implications. In terms of postcranial morphology,the forelimb bears a mixture of features that favor quadrupedalism with restricted
abduction and overhead extension, providing stable contact and support along
branches. In contrast, the hind limb appears to allow for a wider range of movement
in all joints, with an emphasis on thigh extension and abduction, leg rotation, and
powerful grasping with a habitually inverted foot. Interspecifi c variation reveals
traits that can be ultimately related to subtle differences in the frequency of use of
different positional modes, associated with variable eco-social factors. These
results, deriving from different anatomical regions, provide evidence for understanding
morphological variation across howler species in terms of morphofunctional
adaptations, environmental pressure, and niche partitioning.