Craniodental Variables Research Articles

Correction to: Morphological and genetic characterization of Mount Kenya brush-furred rats (Lophuromys Peters 1874); relevance to taxonomy and ecology

Brush-furred rats (Lophuromys Peters 1874) are the most abundant and widely distributed small mammals on Mount Kenya. However, their ecology is poorly known and their taxonomic status is questionable. This study investigates whether or not the morphology and genetics of the Mt. Kenya Lophuromys correspond with elevation, vegetation, and climate variables. We also investigate the taxonomic relationship of the Mt. Kenya Lophuromys to the Aberdare Range and Mt. Kilimanjaro populations using genetic and craniodental data. Specimens were captured along Mt. Kenya’s western and eastern slopes, and other specimens (from Aberdare and Mt. Kilimanjaro) were obtained from Museum collections. The datasets were analyzed using multivariate and univariate statistics, discriminant function analysis, and phylogenetic analyses. The results show that Mt. Kenya Lophuromys specimens from different habitats and elevations are significantly differentiated by external morphology but not craniodental variables, and have low genetic variation and no population genetic structure, supporting the entire population is consistent with a single species model. In addition, Mt. Kenya and Aberdare Lophuromys cluster separately from Mt. Kilimanjaro Lophuromys based on craniodental analyses while phylogenetic and haplotype analyses also support the Mt. Kenya and Aberdare Lophuromys as evolutionarily isolated from Mt. Kilimanjaro’s population. These results contradict recent studies that hypothesized the distribution of Lophuromys margarettae in lower elevations of Mt. Kenya with Lophuromys zena restricted to the higher elevations.

Molecular and morphological evidence of the diversification in the gray mouse opossum, Tlacuatzin canescens (Didelphimorphia), with description of a new species

The gray mouse opossum (Tlacuatzin canescens) is a poorly studied marsupial endemic to Mexico. Phylogenetic or phylogeographic information on this species and its evolutionary history is scarce and scattered. We investigated the origin and the diversification of this taxon using molecular and morphological data. We examined mitochondrial (cytochrome-b) and nuclear (interphotoreceptor retinoid-binding protein) sequences to test species monophyly and assess phylogenetic relationships within the species. We also used multivariate statistical analyses of 13 craniodental variables to assess the phenotypic distinctiveness of mitochondrial haplotypic clades. Phylogenetic analyses revealed that T. canescens is a monophyletic group divided into 5 well-differentiated clades. Genetic divergence among clades was 3.1–8.9%, while the intragroup divergence was 0.5–3.7%. Our molecular clock estimates indicate that the diversification of this taxon occurred during the Pleistocene, which suggests that climatic changes and the presence of geographical barriers influenced the genetic differentiation of its populations. Morphological analyses also showed that there are cranial differences among these clades. Our results suggest the recognition of T. gaumeri, T. insularis, and T. sinaloae as valid species, and the recognition of 1 clade that we describe here as a new species.

The conundrum of subspecies: morphological diversity among desert populations of the California vole (Microtus californicus, Cricetidae)

Author(s): Patton, JL; Conroy, CJ | Abstract: We examined geographic trends in 4 morphological data sets (both craniodental and colorimetric measurements and scores of cranial foramina and qualitative craniodental variables) within and among 5 subspecies of the California vole, Microtus californicus, that occur within or adjacent to the Mojave Desert in eastern California. These analyses are corollary to those previously published on the same samples using both mitochondrial and nuclear gene sequences and microsatellite loci. The morphological and molecular data sets are generally concordant in supporting the existing infraspecific taxonomy, although important conflicts are evident. With the combination of data sets, we are able to assign previously unknown samples to these infraspecific taxa. We define and provide an emended diagnosis of each subspecies using the criteria established by Willi Hennig in his 1966 assessment of the qualities and characteristics of infraspecific taxa, which he understood to be fundamentally different than the hierarchical phylogenetic system he established as the conceptual framework for taxa at the species level and above. Hennig's views are contrary to how the subspecies concept has been applied in much of recent mammalian taxonomy.

Morphometric patterns in assemblages of Cricetid rodents from the Central and Western Cordilleras of Colombia

The mechanisms that mediate the formation and coexistence of species assemblages have been a historical issue in evolutionary ecology, raising the question of whether these assemblages are shaped at random or are influenced by biotic and abiotic processes. An increasingly popular hypothesis points out that certain patterns or rules determine coexistence patterns within assemblages at a regional or continental scale. Thus, morphological and ecological similarities could influence the degree and intensity of competition between species. Considering the morphology of organisms within an environmental framework, we could assess the morphology and understand the ecological role of a given species within the assemblage. This study assesses the similarities and differences of Andean rodents within local assemblages through a Principal Component Analysis (PCA), using craniodental characters of these species to establish whether the relationships between morphometry and coexistence provide evidence to explain assemblage structure patterns. We measured rodent specimens deposited in the Coleccion Teriologica of the University of Antioquia, collected from the Western and Central cordilleras of Colombia. We recorded 15 craniodental variables from all specimens, which were analyzed with a PCA to search for a general organization pattern within assemblages. Afterwards, we plotted the scores for principal components 1 and 2 to evidence the separation or clustering of specimens in an Euclidean space. We recorded 424 specimens from 10 genera and 18 species of the family Cricetidae, with the genera Nephelomys and Thomasomys showing the largest number of specimens. In the overall PCA, the first three components account for 85.1 % of the variation, with 63.9 % for PC1. The variables with the greatest contributions to PC1 were APZ, AA and AFM; to PC2, LFI, APZ and AFM; and to PC3, LFI, LO and LHM. We detected some overlapping and scattering patterns among species at the morphospace defined by PC1 and PC2. We recovered an arrangement of species that shows differences in size and shape between them (as a function of their morphology), as evidenced in the scatter plots for the regional and local analyses. Besides, we did not find a general pattern for the load of variables, although some of these accounted for a larger part of the variation in the overall and local analyses (APZ, AFM, LFI, LHM and AR), indicating the segregation among species. Although the local analyses revealed a similar pattern with these loads changing from site to site, five variables account for the largest variation, what we interpret as a key role to determine the morphometric and/or ecological segregation among species. We believe this first approximation shows the value of ecomorphological studies in understanding patterns of diversity and geographic replacement of species; these patterns should be integrated with analyses of ecological aspects to understand the coexistence of species within local assemblages.

Morphofunctional segregation in Molossid bats (Chiroptera: Molossidae) from the South American southern cone

Molossid bats exhibit a great diversity of size and skull morphology which likely reflect a trophic function and may be indicative of the degree of resource partitioning and overlap. We explored the morphofunctional variation of the skull in molossid species from Argentina, where 18 species had been recorded, and are representative of the vast South American Southern Cone region. We measured 18 craniodental variables in 377 specimens representing all 18 species. We performed a multivariate analysis using craniodental variables, and we used a comparative phylogenetic method, to determine the importance of phylogeny in morphofunctional variation. The specimens distribution in morphospace showed a clear segregation between species on the basis of skull size and morphological differences related with prey selection, and associated with other important factors such as echolocation and flight. We show that the morphological pattern observed was determined principally by the evolutionary history of the family, we identified major events of expansion of occupied morphospace with the origination of large species such as those in Eumops as well as small species of Molossops and Cynomops . We believe that the joint effects of history, size and functional morphology busted the evolution of Neotropical molossids and facilitated the coexistence of related species.

Cryptic diversity in Hipposideros commersoni sensu stricto (Chiroptera: Hipposideridae) in the western portion of Madagascar

BackgroundThe Commerson’s leaf-nosed bat, Hipposideros commersoni sensu stricto, is endemic to Madagascar and is relatively common in the western portion of the island, where it is found in areas, including forested zones, from sea level to 1325 m. A previous study on morphological patterns of geographic variation within the species highlighted the presence of two distinct morphotypes; larger individuals in the north portion of the island and smaller individuals in the south. The main aim of this study was to use a combination of craniodental morphology and molecular data (mitochondrial and nuclear) to test previous hypotheses based on morphology and clarify the evolutionary history of the species group.MethodsWe sequenced mitochondrial and nuclear genes from Hipposideros commersoni obtained from the western portion of Madagascar, and compared them with other African species as outgroups. We analyzed the sequence data using Maximum Likelihood and Bayesian phylogenetic inference. Divergence dates were estimated using Bayesian molecular clock approach. Variation in craniodental variables was also assessed from sequenced individuals.ResultsThe molecular analyses suggest that H. commersoni is not monophyletic, with strong support for the presence of several independently evolving lineages. Two individuals amongst those sequenced from Isalo (south central) and Itampolo (southwest) form a separate clade (Clade A), distinct from other H. commersoni, and sister to continental African H. vittatus and H. gigas. Within the H. commersoni clade, the molecular data support two geographically distributed clades; one from the south (Clade B) and the other from the north (Clade C), which diverged approximately 3.38 million years ago. Morphometric data were consistent with the molecular analyses, suggesting a north–south break within H. commersoni. However, at some localities, animals from both clades occurred in sympatry and these individuals could not be differentiated based on external and craniodental measurements.ConclusionsUsing a combination of molecular and morphological characters, this study presents evidence of cryptic diversity in H. commersoni on Madagascar. Further fine-scale phylogeographic studies are needed to fully resolve the systematics of H. commersoni. This study highlights the utility of the combined approach in employing both morphological and molecular data to provide insights into the evolutionary history of Malagasy population currently assigned to H. commersoni.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0510-2) contains supplementary material, which is available to authorized users.

Characterizing cryptic species: A morphometric analysis of craniodental characters in the dwarf galago genus Galagoides.

The true dwarf galagos of the genus Galagoides, G. demidoff and G. thomasi, are difficult to distinguish morphologically at a specific or subspecific level, and most taxonomic designations are based primarily on geographic localities. We used morphometrics to investigate the morphological diversity of the genus. We conducted statistical analyses of 12 linear measurements on 290 Galagoides skulls housed in museums worldwide, and assembled body weights for 71 wild caught specimens. We examined sexual dimorphism and specific and subspecific distinctiveness using MANOVA, ANOVA, principle components analysis and canonical variate analysis. We distinguished skulls identified as Galagoides demidoff and G. thomasi with ∼70% reliability, and demonstrated consistently different patterns of static allometry in craniodental variables. Variables supporting specific distinction included M1 width, palate width at P2 , palate (snout) length, length of premaxillary tube, width across mastoids, and total skull length. The type specimens of G. orinus and G. rondoensis were significantly different from G. demidoff and G. thomasi, but grouped with them in a CVA including G. zanzibaricus and G. granti, although molecular studies indicate that their true affiliation is with the latter species. Subspecies within G. demidoff could not be distinguished using craniodental morphometrics. Galagoides demidoff and G. thomasi can be distinguished relatively reliably, and are broadly sympatric across western and central Africa. Neither species showed evidence of sexual dimorphism in craniodental size or shape. Size variation has a greater influence on skull morphology in G. demidoff than it has on G. thomasi. Am J Phys Anthropol 158:288-299, 2015. © 2015 Wiley Periodicals, Inc.

Primer registro de Anoura aequatoris (Lömberg, 1921) (Chiroptera: Phyllostomidae) para Bolivia

Herein we introduce the first Bolivian record of the phyllostomid nectar feeding bat Anoura aequatoris collected at Chijchijpa, La Paz, Bolivia. The new record represents a substantial latitudinal extension in the distribution of the species of 04°25’ with respect to the southernmost known record from Pasco, Oxapampa, Peru. The phenetic variation of the herein presented new record of A. aequatoris is investigated through a principal components analysis performed on nine craniodental variables including all recognized species in the A. caudifer complex. Finally, comments on the taxonomy of the group are also presented.

A new uintan horned brontothere from Wyoming and the evolution of canine size and sexual dimorphism in the Brontotheriidae (Perissodactyla: Mammalia)

ABSTRACT Diplacodon gigan is a new species of uintan brontothere recognized from an exquisitely preserved skull from the Wiggins Formation, Hot Springs County, Wyoming. Close affinity to Protitanotherium emarginatum has been suggested based on similarities of canine size and horn shape. However, evidence suggests that canine size and horn morphology were sexually dimorphic among brontotheres, and differences in these traits between single specimens or very small samples of specimens are suspect. Analysis of coefficients of variation of canines and other craniodental variables in brontotheres demonstrates a marked increase in the intraspecific variability of canines among horned brontotheres and closely related hornless species. The evolution of sexual dimorphism in the Brontotheriidae follows a pattern repeated in the evolutionary histories of other ungulates, including ruminants and rhinoceroses, where the evolution of sexually dimorphic canines or canine-like incisors commonly precedes the evolution of horns or horn-like cranial appendages. A phylogenetic analysis, which incorporates new character data on horn size, horn shape, canine size, and canine dimorphism, places D. gigan as the sister of D. elatus, and is the basis for the referral of this new species to Diplacodon. Phylogenetic analysis demonstrates that similarities between P. emarginatum and D. gigan, particularly with respect to canine and horn morphology, are plesiomorphic traits shared with basal horned brontotheres, such as Protitan. The shared nasal bone morphology of D. elatus and D. gigan, where the lateral margins of the nasal bone are angled markedly dorsalward, is a synapomorphy of the genus Diplacodon and is not observed in other brontotheres.

Morphofunctional and geographic segregation among species of lasiurine bats (Chiroptera: Vespertilionidae) from the South American Southern Cone

Four morphologically similar species of insectivorous bats in the genus Lasiurus (Chiroptera: Vespertilionidae) regularly occur in the American Southern Cone. Three of them ( Lasiurus cinereus , L. blossevillii and L. ega ) are sympatric over many regions, whereas the remaining species ( L. varius , closely related to L. blossevillii ) is allopatric, occurring in the Patagonian Temperate Rainforest. A multivariate analysis of 14 craniodental variables for 99 specimens from the four species confirmed size separating two small species from two large ones, and revealed morphofunctional aspects of mastication segregating the two large species on the basis of differences in temporal muscle function (coronoid process height and length of rostrum). We predict ecological (trophic) differences among these lasiurines consistent with their segregation in the morphofunctional space and in combination with the sympatric vs. allopatric condition of species pairs or triads.

Morphofunctional patterns in Neotropical felids: species co-existence and historical assembly

Extant felids are morphologically homogeneous, probably as a result of recent radiation and constraints from their predatory specializations. The Neotropical assemblage comprises 12 of the 41 extant felid species, which occupy all habitats available, with many species coexisting locally. We studied this assemblage on the basis of 31 craniodental variables reflecting morphofunctional variation, measured from 229 specimens representing all 12 species. Multivariate patterns were summarized allowing for phylogenetic covariation. Additional factors (geographical distribution, use of habitat and stratum, and activity pattern) were coded for each species. As expected, body size accounted for most variation, covarying with membership to three deep clades and, to a lesser extent, with large-scale geographic variation. The species tend to segregate in morphospace plus one or more factors (e.g. habits) that make interspecific overlap in niche space minimal. Using dated phylogenies, biogeographic history, and the fossil record, we reconstructed the historical assembly of the Neotropical felid guild. We found a pattern of successive invasions and speciation in which new lineages occupied previously vacant areas of morphospace, or new species occupied overlapping areas but with contrasting habits. This may be general among antagonistic species of historically structured guilds, and we predict similar patterns in other continents. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 711–724.

Demythologizing Arctodus simus, the ‘short-faced’ long-legged and predaceous bear that never was

ABSTRACT In this study, we review the previous evidence on the paleobiology of the giant, ‘short-faced’ bear Arctodus simus (Mammalia: Carnivora: Ursidae) and contribute new ecomorphological inferences on the paleobiology of this enigmatic species. Craniodental variables are used in a comparative morphometric study across the families Felidae, Hyaenidae, Canidae, and Ursidae. Principal components analyses (PCAs) do not show an ecomorphological adaptation towards bone-cracking or hypercarnivory in the ‘short-faced’ bear. In contrast, PCAs and discriminant analyses restricted to the craniodental data set of ursids suggest close morphological resemblance between A. simus and the extant omnivorous bears. In addition, the scaling of snout length on neurocranial length in bears indicates that the face of A. simus was not particularly short. Body mass estimates obtained from major limb bone measurements reveal that A. simus specimens of around 1000 kilograms were more common than previously suspected. Scaling relationships in extant bears of limb lengths on the least width of the femoral shaft (the variable best correlated with body mass) indicate that A. simus was not as relatively long-legged as previously thought. For these reasons, although the isotopic signature of A. simus has been interpreted as evidencing that it consumed large amounts of flesh relative to some contemporary populations of Ursus arctos, our results do not support the previous views of A. simus as a fast-running super-predator or as a specialized scavenger. In contrast, the picture that emerges from this study is one of a colossal omnivorous bear whose diet probably varied according to resource availability.

Morphological Differentiation among Three Species of Flying Squirrels (Genus Hylopetes) from Southeast Asia

The genus Hylopetes consists of 8 or 9 species of small flying squirrels. There has been much nomenclatural confusion over 3 of these species: H. platyurus (the gray-cheeked flying squirrel), H. spadiceus (the red-cheeked flying squirrel), and H. lepidus (the pink-cheeked flying squirrel). To address this taxonomic problem, we examined museum specimens and quantified pelage coloration, tail shape, and a number of craniodental characters. A discriminant analysis of craniodental variables discriminated among the 3 species and allocated all specimens correctly (P < 0.00001). We found that simple ratios of craniodental measurements coupled with pelage coloration characters can assist in the identification of these problematic species, although tail shape was not useful for discrimination. Based on our results as well as historical accounts and what is known about the biogeographical patterns of the region, we provide a description and discussion of the distributions for these species.

Estimating body mass in New World “monkeys” (Platyrrhini, Primates), with a consideration of the Miocene platyrrhine, Chilecebus carrascoensis

Well-constrained estimates of adult body mass for species of fossil platyrrhines (New World “monkeys”) are essential for resolving numerous paleobiological questions. However, no consensus exists as to which craniodental measures best correlate with body mass among extant taxa in this clade. In this analysis, we analyze 80 craniodental variables and generate predictive equations applicable to fossil taxa, including the early platyrrhine Chilecebus carrascoensis.We find mandibular length to be the best craniodental predictor of body mass. There is no significant difference in predictive value between osteological and dental measures. Variables associated with the mandible and lower dentition do significantly outperform the cranium and upper dentition. Additionally, we demonstrate that modern platyrrhines differ, morphometrically, from early fossil forms. Chilecebus possesses unusual cranial proportions in several key features, as well as proportionally narrow upper incisors and wide upper cheek teeth. These variables yield widely divergent body mass estimates for Chilecebus, implying that the correlations observed in a crown group cannot be assumed a priori for early diverging fossils. Variables allometrically consistent with those in extant forms yield a body mass estimate of slightly less than 600 grams for Chilecebus, nearly a factor of two smaller than prior preliminary estimates.Scaled to body mass, the brain of Chilecebus is markedly smaller than those of modern anthropoids, despite its lowered body mass estimate advocated here. This finding, in conjunction with a similar pattern exhibited by fossil catarrhines, suggests that increased encephalization arose independently in the two extant subgroups of anthropoids (platyrrhines and catarrhines).

On the distinctiveness of the Cape lion ( Panthera leo melanochaita Smith, 1842), and a possible new specimen from the Zoological Museum, Copenhagen

The Cape lion was a population of lions that probably inhabited the western part of the Cape Province of South Africa until their extermination by man in the mid-19th century. Only a few skeletal remains are known, making every specimen valuable. In this paper, I report on a possible new male specimen CN1570 from the Zoological Museum in Copenhagen. A multivariate discriminant analysis on 27 craniodental variables provided clear separation between four of the five lion subspecies ( Panthera leo krugeri, nubica, persica, senegalensis) that were included, whereas P. l. bleyenberghi showed some overlap with P. l. senegalensis and P. l. krugeri. The only two undisputed Cape lion males grouped separately from all other lions. CN1570 also grouped separately from other lions, and towards the two Cape lions. The external morphology of the Cape lion is often cited as having been different from other sub-Saharan lions, but phenotypic plasticity argues for caution in placing emphasis on mane morphology as a distinguishing character among lion subspecies. Skull morphology, however, appears to clearly distinguish male Cape lions from other African lions.

Characterizing complex craniodental patterns related to feeding behaviour in ungulates: a multivariate approach

AbstractThis work examines whether stepwise discriminant function analysis of a suite of craniodental variables enables feeding behaviour and habitat preferences to be identified in fossil ungulates. There are several morphological features of the ungulate skull, mandible and dentition that are well correlated with dietary adaptations, and thus can be used for estimating the feeding ecology of extinct taxa. However, most studies have followed an univariate approach for characterizing the relationship between diet and craniodental structure in extant ungulates (but see Pérez‐Barberia &amp; Gordon, 2001), even though such a relationship has been revealed to be complex because of functional, phylogenetic and biomechanical constraints. In this paper a multivariate perspective is followed, developing quadratic discriminant functions for pairwise comparisons of dietary/habitat groups in modern species. Given that the stepwise method for selecting the morphological variables to be included in the algorithms was used, alternative discriminant functions are provided. Results obtained show that these algorithms reclassify correctly the species according to their feeding and habitat ecology, and thus may be useful for obtaining reliable palaeoautecological inferences (i.e. those related to the life style of extinct species, such as feeding ecology and habitat preferences) when applied to extinct ungulate taxa.

Prediction of marsupial body mass

Cranio-dental variables are correlated with body mass in marsupials, using a species data-set derived from extant australidelphian representatives, to predict body mass in fossil species. Thirty-eight extant australidelphian species, including 10 dasyuromorphians, 22 diprotodontians, 1 notoryctomorphian and 5 peramelemorphians, were analysed. Where sexual dimorphism was prominent, genders were evaluated separately. Twenty-nine cranio-dental variables were measured for each specimen and species averages calculated. Body masses were taken as recorded for each specimen or as published species averages. The cranio-dental measures for each morpho-species were then regressed against average body mass in four distinct data-sets: (1) the entire species sample, (2) only dasyuromorphian taxa, (3) only diprotodontians, and (4) all species excluding dasyuromorphians. Each cranio-dental variable was then ranked according to various error statistics and correlation coefficients. Results suggest that predictors of body size in eutherians (such as first lower molar area), commonly used to estimate body mass in marsupials may not be reliable or accurate indicators. Significant differences in the usefulness of predictor variables between taxonomic data-sets were also observed. Total jaw length is the most reliable predictor for diprotodontians, as well as for all species combined, whereas lower molar row length appears to be more appropriate for dasyuromorphians. Multiple variable regressions variably offer more precision than those derived from individual parameters. On the basis of these data, body mass estimations are provided for a number of extinct marsupial taxa.

Taxonomy and distribution of the sigmodontine rodents of genus Necromys in central Argentina and Uruguay

The taxonomic status of the species of Necromys Ameghino, 1889 (= Bolomys Thomas, part), inhabiting the pampean region of Argentina and southern Uruguay is not clear. The two most recent systematic hypotheses both distinguish two species. Massoia and Fornes (1967) recognized Necromys obscurus (Waterhouse, 1837) with allopatric populations in southern Uruguay and southeastern Buenos Aires Province (Argentina), and N. benefactus (Thomas, 1919) distributed in a strip across northwestern -southwestern Buenos Aires Province. Reig (1987) argued that the populations of Uruguay and northwestern Buenos Aires Province belong to N. obscurus (including N. benef actus as a subspecies), while those of the southeast and southwest are referred to an unnamed taxon. To solve this problem, 152 specimens from Argentina and Uruguay were studied using morphometric data and qualitative characters. Craniodental variables were measured in 97 adult specimens of both sexes. Discriminant-function analysis among preestablished geographic groups and cluster analysis using Mahalanobis distances revealed the presence of two groups with contrasting morphological characteristics. The first group, which corresponds to N. benefactus, includes the populations from northern La Pampa, southern Santa Fe, and northwestern, centralwest, and southwestern Buenos Aires Province (Argentina). The second group, N. obscurus, includes the populations from Uruguay (N. obscurus obscurus) and from southeastern Buenos Aires Province (a new subspecies).

The relationship between forelimb morphology and behaviour in North American carnivores (Carnivora)

We tested the validity of previously described relationships between forelimb structure and behaviour in mammals by measuring the forelimbs of 22 species of North American carnivores. Nine ratios were calculated from these measurements and made independent of the effects of allometry and phylogeny through the use of log-transformed regressions and independent contrasts analysis. The ratios were then directly compared with two behavioural traits: arboreal locomotion and vertebrate predation. Only five of the nine ratios exhibited a significant relationship with arboreal locomotion and three with vertebrate predation. It was concluded that the brachial index, relative size of the olecranon process, and total forelimb robusticity may be reliable predictors of arboreal locomotion, and that the brachial index, relative size of the olecranon process, and radial robusticity may be accurate predictors of vertebrate predation. The data also suggest that the morphology of the lower forelimb may be an important indicator of prey-capture and feeding behaviour in carnivores and could be used in conjunction with craniodental variables to extrapolate predatory behaviour of extinct species.

Body size in mammalian paleobiology: estimation and biological implications

1. Introduction J. Damuth and B. MacFadden Part I. The Biological Significance of Mammalian Body Size: 2. The physiological significance of body size B. K. McNab 3. The behavioral/ecological significance of body size J. F. Eisenberg 4. The functional anatomy of body weight T. Grand 5. Evolutionary strategies and body size in a guild of mammals V. C. Maiorana 6. The cotton rat model R. A. Martin Part II. The Estimation of Mammalian Body Mass: 7. Methods and problems in estimating body size in fossil primates W. Jungers 8. Structural allometry of the lower limb bones in the Anthropoidea C. Ruff 9. Skeletal and dental predictors of body weight in carnivores B. Van Valkenburgh 10. Estimates of body size for insular dwarf mammoths V. L. Roth 11. Skeletal dimensions of ungulates as predictors of body weight K. M. Scott 12. Correlation of body weight in ungulates with cranio-dental variables C. Janis 13. Problems with using tooth size to estimate the body size of fossil mammals M. Fortelius 14. Problems in estimating body masses of archaic fossil ungulates using dental measurements J. Damuth 15. Body-size estimates and size distribution of ungulates (Mammalia) from the Late Miocene Love Bone Bed, Florida B. J. MacFadden and R. C. Hulbert 16. Summary: discussion and recommendations for body-mass estimation J. Damuth and B. J. MacFadden Appendices: data and equations for body-mass estimation.