Transitions Leading Up To The Archontan And Euprimate Locomotor Strategies And
I will not belabor the platitude that the postcranial record of Mesozoic eutherian or other mammals is still relatively poor, and that such a state of affairs makes for very tentative conclusions regarding locomotor adaptations in the stems of various higher taxa within the Eutheria, Metatheria, and Theria the latter restricted here to the concept of monophyletically tri-bosphenic mammals . There is certainly overwhelming evidence that the extant Metatheria had a specifically arboreal ancestry,...
JawMuscle EMG and Jaw Morphology in Treeshrews and Primates
Belanger's treeshrews, greater galagos and ring-tailed lemurs are more similar to each other in jaw-muscle EMG activity patterns as compared to this anthropoid sample. Given this broad resemblance, we find it worthwhile to ask whether treeshrew jaw morphology is also more similar to strepsirrhines than anthropoids. If so, then we can extend the associations among jaw-muscle activity patterns, inferentially internal jaw forces, and jaw form observed in comparisons of the primate suborders to...
Evolution of Lysozymes in Colobine Monkeys
Lysozyme is a ubiquitous bacteriolytic enzyme found in virtually all animals. Its function is to cleave the P 14 glycosidic bonds between N-acetyl glu-cosamine and C-acetyl muramic acid in the cell walls of bacteria. As it is present in body fluids, such as saliva, serum, tears, etc., it is often the first line of defense against foreign bacteria. In foregut fermenters, which are animals whose anterior part of the stomach functions as a chamber for bacterial fermentation of ingested plant...
Critical Primate Adaptations
Neglecting the petrosal bulla and a few other pedantries of uncertain adaptive significance, there is widespread agreement that some of the most important shared primate attributes reflecting something about the adaptive context of primate origins include the following 1 grasping hands and feet with nails rather than claws, and locomotion utilizing diagonal footfall patterns, 2 notable development of functional stereoscopy through orbital convergence, 3 large brain relative to body size, and 4...
Likelihood Versus Bayesian Results
Given that Bayesian methods are relatively new in phylogenetics, it is reassuring that independent Bayesian runs with the full data set resulted in trees that are topologically identical to each other and to the maximum likelihood tree when analyses were performed under the GTR r I model of sequence evolution. Maximum likelihood bootstrap percentages were generally lower than Bayesian posterior probabilities. The observation that bootstrap support proportions are lower than Bayesian posterior...
Primate Superior Colliculus In Attention And Action
With the cortical projections to the superior colliculus, this account of primate brain specializations comes full circle. The SC, an ancient structure involved in the control of eye, head, and forelimb movements through its descending projections, is also the linchpin of the highly derived forebrain systems of primates involved in visuospatial attention and vision for action. As we have seen, the SC is in a critical position to influence a wide array of cortical areas by means of its ascending...
Dorsal Pulvinar And Related Cortical Networks
The largest component of the thalamus in anthropoid primates is called the pulvinar, a structure composed of several major divisions, usually termed the inferior, lateral, medial, and oral anterior pulvinar nuclei Gutierrez et al., 2000 . This terminology is generally not used in nonprimate mammals, although it is clear that at least some components of the primate pulvinar have homologues in other mammals. The anterior pulvinar of primates is related to the somatosensory system, and may be...
Eye Shape Measures
On the basis of the dioptric principles outlined in the Introduction, visually dependent nocturnal animals are predicted to have large pupils relative to focal length, and visually dependent diurnal animals are predicted to have small pupil diameters for their focal lengths. These dimensions cannot be measured accurately in preserved eyes and are known for only a small number of vertebrates e.g., Arrese, 2002 Hughes, 1977 Martin, 1999 . Here, we use the axial diameter of the eye as a surrogate...
Skull Characters and Conclusion
The study of paromomyid skulls underscores the difficulty of interpreting partial and distorted specimens. Studying a crushed skull of Phenacolemur jepseni showing parts of the middle ear, Szalay 1972 inferred the presence of a petrosal bulla, in agreement with his hypothesis of a petrosal bulla in Plesiadapis Szalay, 1969 . He also tentatively suggested that the base of a ridge on the promontorium continuous with a longitudinal septum could house a bony canal for a promontory artery Szalay,...
Derived Features Of The Mrca
There are a number of characteristics of the postcranium that are hypothesized to distinguish the MRCA of primates from other mammals even though most have been modified in some groups of primates , and most importantly from the most likely sister taxon of Primates, whether that be some member of the Plesiadapiformes, the Scandentia, or the Dermoptera. A partial list of these characters, their presumed mechanical implications and probable biological roles is given in Table 1. As noted by many...
Miniature Flower Specialists
Sussman 1991, 1995, 1999 suggested that the key ecological factor leading to the origin of primates was adaptation to the utilization of angiosperm products fruit and flowers at the tips of terminal branches. There is still some question as to whether one particular food item was crucial in the evolution of the earliest primates, or whether primate adaptations are better seen as related to a general exploitation of terminal branch resources. The presence in Australasia of several independent...
Likelihood and Bayesian Analyses with the Full Data Set
Figure 1 shows a maximum likelihood cladogram -ln likelihood 211,110.54 for the 16.4 kb data set under the GTR r I model of sequence evolution. Caniform Pangolin Flying fox Rousette fruit bat Rhinolophoid bat Phyllostomid microbat Free-tailed bat Hedgehog Shrew Mole Mouse Rat Hystricid Caviomorph Sciurid Rabbit Pika Flying lemur Tree shrew Strepsirrhine Human Sloth Anteater Armadillo Tenrec Golden mole s. e. elephant shrew l. e. elephant shrew Aardvark Sirenian Hyrax Elephant Opossum...
Taxonomy
The order Scandentia is represented by the single family Tupaiidae, which includes the subfamilies Ptilocercinae and Tupaiinae Table 1 . Ptilocercinae is represented only by Ptilocercus lowii, while Tupaiinae consists of Tupaia 14 species , Dendrogale 2 species , Urogale everetti, and Anathana ellioti see Table 1 Wilson, 1993 . Differences in postcranial morphology are often split down the subfamilial line, as Ptilocercus' postcranium is adapted for arboreal locomotion, while that of the...
Section I Supraordinal Relationships of Primates and Their Time of Origin
Despite new fossil discoveries, new sources of data, and new methods of analysis, several important issues concerning the origin and phylogeny of Primates remain unresolved. One currently controversial issue is the time of origin of the Order Primates. Both the analysis of molecular data Springer et al. and mathematical modeling Soligo et al. suggest a time of origin in the middle of the Cretaceous period 80-90 MYA , while the earliest fossil record of primates is only 55 MYA. The fossil record...
References Oww
Bader, R, and Hall, J., 1960, Osteometric variation and function in bats, Evol. 14 8-17. Beard, K. C., 1990, Gliding behaviour and palaeoecology of the alleged primate family Paromomyidae Mammalia, Dermoptera . Nature 345 340-341. Beard, K. C., 1993, Phylogenetic systematics of the Primatomorpha, with special reference to Dermoptera, in F. Szalay, M. Novacek, and M. McKenna, eds., Mammal Phylogeny Placentals, Springer-Verlag, New York, pp. 129-150. Beard, K. C., Qi, T., Dawson, M. R., Wang, B.,...
Form
The Nocturnal Visual Predation Hypothesis NVPH argues that in the first modern primates, a shift to nocturnal visual predation on small invertebrates and vertebrates necessitated more anteriorly directed and medially approximated orbital apertures and eyeballs Figure 6A Cartmill, 1970, 1972, 1974, 1992 also Collins, 1921 . This increased orbital convergence in turn results in a larger binocular field for greater stereoscopic vision, as well as an exceptionally clear retinal image during...
Metabolic Variation in Strepsirrhines and Haplorhines
Metabolic rates in the strepsirrhines are significantly lower than those predicted by the Kleiber scaling relationship, averaging 38.6 4.7 below the norm Table 1 . The range of predicted values for strepsirrhines is from -1.52 to -69.22 below those predicted by the Kleiber scaling relationship, and 14 of the 17 strepsirrhine species are hypometabolic by criteria described above i.e., gt 20 below predicted by Kleiber scaling relationship . Euoticus elegan-tulus, Galago moholi, and Galago...
Primate Taxonomy Plesiadapiforms and Approaches to Primate Origins Silcox M T
Problems with Combining Cladistics and Linnean Taxonomy Phylogenetic Taxonomy's Solutions to the Problems Posed by Linnean Taxonomy Other Taxonomic Priorities Previous Definitions and Diagnoses of Primates The Phylogenetic Position of Plesiadapiformes Background A More Comprehensive Analysis Taxonomic Implications of the Current Analysis Primate Taxonomy and the Study of Euprimate Origins Conclusions Acknowledgments References
Nocturnal Visual Predation and the Evolution of Orbit Orientation and the
The interspecific analyses indicate that the presence of a postorbital bar is correlated with greater orbital convergence in herpestids and pteropodids, and with increased orbital frontation in felids and herpestids. Therefore, moderate support is provided for the NVPH's prediction about orbital convergence, as well as our suggestion regarding the influence of orbital frontation. As both orbital parameters increase during euprimate origins Cartmill, 1970, 1972, 1974, 1992 Fleagle, 1999 Martin,...
Micromomyid Skeleton An Example from a Late Paleocene Limestone
We are in the process of preparing a block, originally 20 kg in mass, of fossil-iferous limestone from the last zone of the Clarkforkian land-mammal age Cf-3, locality SC-327 see Bloch and Boyer, 2001 for locality information . One amazing aspect of this rather large block is that all of the exposed skeletons, representing at least 11 individuals, are articulated 80-100 complete see Bloch and Boyer, 2001, Figure 5 . At least one of the individuals is a new genus and species of micromomyid...
Contributors
Jonathan I. Bloch, Florida Museum of Natural History, University of Florida, Gainesville, FL 32611-7800 Douglas M. Boyer, Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-8081 Matt Cartmill, Department of Biological Anthropology and Anatomy, Duke University Medical Center, Durham, NC 27710 Marian Dagosto, Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611-3008, and Department of Zoology Mammals...
Introduction Vyn
Due to the wide range of morphological variability within and among major primate clades, the circumorbital region has long been the focus of functional and phylogenetic investigations. As is well known, all euprimates differ from their putative ancestors in having the more derived character state of a bony postorbital bar along the lateral orbital margins extending between the frontal and jugal bones Cartmill, 1970, 1972, 1974, 1992 Fleagle, 1999 Matthew J. Ravosa Department of Cell and...
Data Sets
The synthetic treatment of very large data sets by Simmons 1993 and Silcox 2001 is very interesting. Simmons searched for all possible morphological characters studied in the literature, established in 10 presumably mono-phyletic units Scandentia, Strepsirhini, Tarsiiformes, Anthropoidea, Galeopithecidae, Megachiroptera, Microchiroptera, Plesiadapidae, Paromomyidae, and Micromomyidae . The most striking result of her analysis is that, in partitioning the data set into six different subsets...
Treeshrew Feeding Ecology and Jaw MorphologyA Reasonable Early Primate Model
Treeshrews represent an enigmatic group of small mammals that have bewildered primatologists for over a century. This confusion persists in part because of our poor understanding of treeshrew ecology. Emmons 2000 has provided a much-needed field study of treeshrew behavioral ecology. Emmons 2000 emphasizes that the ecological diversity among treeshrew species makes it difficult to summarize the behavioral ecology of the order. Among treeshrews there are nocturnal and diurnal species, montane-...
Problems with Combining Cladistics and Linnean Taxonomy
The Linnean system of taxonomy is based on hierarchically internested sets of ranks. Common membership in a group indicated by a particular taxonomic name is shown by common usage of that name for the members of the group therefore, all mammals are included in Mammalia. Although this may seem trivial, the result is that the taxonomy communicates a hypothesis about common group membership and, in an evolutionary context, common descent. The result is that Linnean taxonomic names can and often do...
Returning To Tupaiidae
When Luckett's 1980a book on tree shrews was published, plesiadapiforms were considered by all the contributors primitive primates. This was a relatively broad, though not unanimous, consensus. It is very interesting to examine how the elimination of the Plesiadapiformes from primates affects our interpretation of certain characters. Surprisingly, this elimination renders a whole series of derived characters possible synapomorphies of tupaiids and primates. Figure 5 illustrates how the...
Primate Origins Role Of Autopod Evolution
Studies of primate skeletal remains from the Eocene epoch of North America and Europe have brought to light several derived features of the autopod that distinguish primates from their close relatives the plesiadapiforms, der-mopterans, and tree shrews. This discussion of derived autopod features is restricted to the digital rays and does not include a discussion of the carpus and tarsus, as the morphology of these bones in early primates has been dealt with elsewhere e.g., Dagosto, 1988 Gebo,...
Molecular Classification For The Living Orders Of Placental Mammals
The well-resolved molecular tree that we present provides a basis for classifying the living orders of placental mammals Table 5 . Following McKenna and Bell 1997 , we used mirorder, grandorder, superorder, magnorder, cohort, supercohort, and infralegion as successively more inclusive taxonomic ranks above the rank of order. Our classification includes clades that have been recognized in previous classifications, although in many cases these have not been recognized with formal Linnaean ranks....
Phylogenetic Influences on Strepsirrhine Hypometabolism Comparative Metabolic
From our previous analyses, it appears that proximate ecological factors do not provide a full explanation for strepsirrhine hypometabolism. Consequently, we next considered whether the distinctive metabolic pattern of strepsirrhines is a primitive trait that is shared with other closely related mammalian species. To evaluate this explanation, we considered metabolic data for selected nonprimate species Figure 3 . In the two studies of RMR in tree shrews that were conducted under standardized...
Methods
As described above, several possible neural mechanisms exist to correct for minor eye displacements. These mechanisms, when combined with voluntary and reflexive eye and head movements in a conscious subject, pose problems for measuring eye movements due to masticatory muscle contractions. We attempted to circumvent these difficulties by measuring eye movements in anesthetized subjects. The Institutional Animal Care and Use Committee at Stony Brook University approved animal procedures. The...
Ds Walking And Arboreal Locomotion
When the hindfoot strikes down in a typical DS gait, it lands just behind the forefoot on the same side Figure 3B, no. 6 which is why the unilateral bipod of support is so small Figure 3B, no. 7 . In a tree that hindlimb will be landing on the same support as the forefoot. The animal has already put weight on its forefoot on this support, and so it knows that the support is safe. If the next foot to descend namely, the diagonally opposite forefoot Figure 3B, no. 8 lands on an insecure support...
Peculiarities Of Primate Gaits
The order Primates in the strict sense Euprimates or primates of modern aspect is defined by a familiar suite of synapomorphies. Some of these may represent adaptively neutral contingencies for example, the formation of the auditory bulla by an outgrowth from the petrosal, rather than by a separate entotympanic bone . However, others appear to be telling us things about the basal adaptations of the order. Compared to primitive placental mammals, primates have a reduced sense of smell and an...
Plesiadapiforms as ClawClimbing Arborealists
Plesiadapiform taxa included in the families Carpolestidae, Micromomyidae, Paromomyidae, and Plesiadapidae are similar to each other in many postcranial Figure 2. A Composite drawing of micromomyid plesiadapiform skull and skeleton UM 41870 with numbers on bones corresponding to those of anatomical layout. Scale 1 cm. Figure 2. A Composite drawing of micromomyid plesiadapiform skull and skeleton UM 41870 with numbers on bones corresponding to those of anatomical layout. Scale 1 cm. Figure 2....
Important Tarsal Characters
A series of tupaiid tarsal characters were interpreted by Szalay and Drawhorn 1980 as derived as opposed to primitive archontan retentions astragalus with the groove for the tendon of M. flexor digitorum fibularis aligned parallel to the long axis and located upon a ventrally projecting medial body length of the astragalus relatively large in contrast to the squat bones in Paleogene archontans sulcus astragalus not approaching the trochlear groove for the tendon of M. flexor fibularis this may...
Carpolestidae
Insights into the behavior of the Carpolestidae are derived primarily from a single specimen of the Late Paleocene taxon, Carpolestes simpsoni Bloch and Gingerich, 1998 . The specimen is fairly complete Figure 3C and the dental associations are well documented Bloch and Boyer, 2001, 2002b . Carpolestes is unique among plesiadapiforms in having a foot that is better adapted for powerfully and precisely grasping small diameter supports, a UAJ that reflects even more freedom of motion, a humerus...
Orbital Convergence
Primates have long been noted to have more convergent orbital apertures than most other mammals. Early explanations related convergence to arbore-ality Elliot Smith, 1924 Le Gros Clark, 1959 Wood Jones, 1916 . However, comparisons with other animals suggested to Cartmill 1970, 1972 that convergent orbits facilitated visual predation on insects in the fine branches of the shrub layer of tropical rainforests. Cartmill argued that Stereoptic integration of the two visual fields improves the...
SPECIALIZATIONS OF THE VISUAL SYSTEM Overview
Discussion of visual system evolution requires a very brief review of the anatomy of the visual system for more details, see especially Kaas and Huerta, 1988 Kaas et al., 1978 . Visual information reaches the brain by way of projections from the ganglion cells of the retina. Retinal ganglion cells are of several types, with different morphologies and physiological properties. Currently, three main classes of ganglion cells are distinguished, usually called M, P, and K cells in primates. This...
Reproductive Strategies and Primate Evolution
Research has indicated that one primary input to the encephalization levels observed in primates and other mammals relates to reproductive and life history strategies. It is necessary to review our general understanding of these mammalian and primate reproductive strategies prior to assessing these associations with encephalization, however. Building directly on previous work by Adolf Portmann 1939, 1965 , Martin 1972, 1973, 1975a,b noted that mammalian reproductive strategies could be...
Preservational Bias In The Fossil Record
There are several reasons why the preservation rates calculated by Foote et al. 1999 are likely to be overestimated. These all relate to the problem of circularity when interpreting the completeness of the fossil record through analysis of the fossil record alone. First, methods for assessing the completeness of the fossil record based exclusively on the fossil record can only account for gaps that occur within known lineages. They are insensitive to the existence of larger gaps, both...
Dorsolateral Prefrontal Cortex
By convention, neuroscientists recognize two broad divisions of primate frontal cortex, the motor zone, which consists of the primary motor area M1 and a variety of premotor areas, and the prefrontal zone, which comprises the remainder of the frontal cortex. The prefrontal zone can be divided into a medial region consisting mainly of anterior cingulate cortex , an orbital region, and a dorsolateral region. The dorsolateral prefrontal cortex DLPFC has long been a region of special interest to...
Fossils Methods and Primate Origins
In any attempt at deciphering primate origins within archontans, we should never forget the significance of 1 the divergence of skull form in paro-momyids, plesiadapids carpolestids and 2 a divergent, cross specialized, and continuous record of dentitions, which further eliminates plesiadapiforms from any ancestral role in primate origins. The primatomorph hypothesis is dentally impossible, and cranially very unlikely. The carpolestid hypothesis Bloch and Boyer, 2002 is as dentally impossible...
Orbit Size And Shape
Small-bodied nocturnal primates have long been noted to have larger orbital apertures than small-bodied primates of the same skull length Kay and Cartmill, 1977 Heesy and Ross, 2001 Kay and Kirk, 2000 Walker, 1967 . These differences in orbital aperture dimensions may reflect several aspects of eye size and shape Kirk, 2004 Ross, 2000 . The dioptric principles underlying the relationship between eye shape and activity pattern are illustrated in Figure 3. Nocturnal animals live in scotopic, or...
Encephalization in Extinct Primates
Are the primates of the Paleogene the period of the Early Tertiary comprising Paleocene, Eocene, and Oligocene epochs also generally highly encephalized This question must be addressed in relative fashion as well. Almost all mammalian lineages with substantial fossil records show varying degrees of progressive increase in encephalization throughout the Tertiary Gould, 1975a Jerison, 1973 therefore, any determination of relative brain size in extinct early primates must of necessity be rooted in...
Functional Morphology of the Primate Masticatory Apparatus
What we know about how primates chew and the relationship between form and function of their masticatory apparatus comes from three seemingly disparate research agendas. The earliest and hence most enduring efforts have been made by scientists, dentists, and physicians focused on advancing applied dentistry and related medical fields e.g., Ahlgren, 1966 Bennett, 1908 Carlsoo, 1952 DuBrul, 1988 Gibbs et al., 1971 Lindblom, 1960 Linden, 1998 Moller, 1966 . A second group of researchers have...
Plesiadapiform Specializations A Diversity of Arboreal Behaviors
Despite the large amount of similarity between the four groups of plesiadapiforms considered here, each is also unique in its own way. In some cases, morphological differences are probably engendered by size extremes that change the nature of the arboreal milieu experienced by a given taxon. In other cases, these features truly represent specialized behaviors beyond clinging and claw climbing on large diameter vertical supports and the ability to grasp smaller supports with the hands and feet....
References Mvg
Anemone, R. L., 1993, Functional anatomy of the hip and thigh among Primates, in Postcranial Adaptation in Nonhuman Primates, D. Gebo, ed., Northern Illinois University Press, pp. 150-174. Beard, K. C., 1989, Postcranial Anatomy, Locomotor Adaptations, and Paleoecology of Early Cenozoic Plesiadapidae, Paromomyidae, and Micromomyidae Eutheria, Dermoptera , Ph.D. dissertation, Johns Hopkins University School of Medicine, Baltimore. Beard, K. C., 1990, Gliding behavior and paleoecology of the...
Major Clades of Placental Mammals
Our analyses extend studies with the Murphy et al. 2001b data set and provide robust support for four major clades of placental mammals Afrotheria, Xenarthra, Euarchontoglires, Laurasiatheria . We also find robust support for a Euarchontoglires Laurasiatheria clade i.e., Boreoeutheria Springer and de Jong, 2001 . Sequences for a 1.3 kb segment of the apolipoprotein B gene also recover these clades Amrine-Madsen et al., 2003 . In addition, Waddell et al. 2001 argued for these clades based on...
Summary Qvs
These preceding discussions may be summarized through the development of a four-input framework, which accounts for the key elements and variance in relative brain size within the primates, and between primates as a whole and other mammalian groups. This framework is summarized schematically in Figure 10. First, there is the grade shift linked to strong precociality and small body size in early primate evolution Figure 10, arrow 1 . Second is the primate-wide phylogenetic trajectory, exceeding...
Interpretations of the Masticatory Apparatus in the First Primates
The topic of primate origins has a long history of discussion. We will not review this vast literature. Readers interested in such an appraisal should direct their attention to both earlier publications and recent reviews that consider the origin of primates in their appropriate historical context e.g., Cartmill, 1974 Cartmill, 1992 Jones, 1917 Kay and Cartmill, 1977 Le Gros Clark, 1959a,b Martin, 1993 McKenna, 1966 Smith, 1924 Sussman, 1991 Szalay, 1968 . Instead, we will review references to...
Overview Of Phalangeroid Phylogeny
Until recently all marsupials were usually classified in the indisputably mono-phyletic order Marsupialia, but scientific certainty being what it is to taxono-mists, this tidy order has now been cleaved into a controversial array of ordinal level classifications some of which utilize more than a half dozen orders Aplin and Archer, 1987 Archer, 1984 Ride, 1964 Szalay, 1993, 1994 . A currently popular ordinal designation for the particular marsupials under consideration in this paper is...