cQE: Body Mass Estimates Using Bipedal Correction Factor

Description Usage Arguments Details Value Author(s) References See Also Examples

View source: R/cQE.R

Description

This function presents equations from Campione et al. (2014) for esimating body mass in bipeds using minimum femoral circumference and based on a correction of the quadrupedal equations from Campione and Evans (2012)

Usage

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cQE(FC, equation = "raw", cor = 2, quadratic = FALSE, data = NULL)

Arguments

FC

a value or vector representing femoral circumference (in mm)

equation

desired estimation equation. Two possible choices (See Details)

cor

correction factor to be used (α^2). The default is 2, as per Campione et al. (2014)

quadratic

a logical indicating whether estimates based on the quadratic equation should be used (See Details)

data

an optional object of class = "data.frame" or class = "matrix"

Details

The function includes two different equations. equation = "raw" (default) applies the correction factor derived in Campione et al. (2014) to the raw (non-phylogenetically corrected) bivariate regression equation from Campione and Evans (2012). equation = "phylocor" applies the same correction factor to the phylogenetically corrected equation presented in the same study.

cor = 2 refers to the correction factor (α^2) to be used. The default (cor = 2) refers the initial derivation in Campione et al. (2014), however, this value can be modified based on the level of eccentricity of the femur. A set of values for cor corresponding to set eccentricities can be found in table S2 of Campione et al. (2014).

If quadratic = TRUE, then a second set of estimates will be returned based on a quadratic estimation equation (Campione in review).

If a data object is specified, the mass estiamtes and additional results will be added as columns to the data.frame or matrix within that object.

Value

Eight numeric values or columns are returned if quadratic = TRUE (identified by q):

log.cQE

A numeric value or vector representing the mass estimate(s) in log10 grams

cQE

A numeric value or vector representing the mass estimate(s) in grams

lower.cQE

A numeric value or vector representing the lower prediction error derived for the specific equation in Campione and Evans (2012)

upper.cQE

A numeric value or vector representing the upper prediction error

log.qcQE

A numeric value or vector representing the mass estimate(s) in log10 grams using a quadratic equation

qcQE

A numeric value or vector representing the mass estimate(s) in grams

lower.qcQE

A numeric value or vector representing the lower prediction error derived for the specific equation by Campione (in review)

upper.qcQE

A numeric value or vector representing the upper prediction error

Author(s)

Nicolas E. Campione

References

Campione, N. E. and Evans, D. C. (2012) A universal scaling relationship between body mass and proximal limb bone dimensions in quadrupedal terrestrial tetrapods. BMC Biology, 10, 60.

Campione, N. E., Evans, D. C., Brown, C. M. and Carrano, M. T. (2014) Body mass estimation in non-avian bipeds using a theoretical conversion to quadruped stylopodial proportions. Methods in Ecology and Evolution, 5(9), 913-923.

Campione, N. E. (in review) Extrapolation of a universal scaling relationship for estimating body masses in extinct terrestrial vertebrates.

See Also

QE bipeds AHR1985 CF2004 CM1992

Examples

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##Bipedal dinosaurs
data(dinosbip)

#Estimates for Tyrannosaurus (FMNH PR 2081 "Sue")
sue<-which(dinosbip$Taxon=="TyrannosaurusFMNH2081")
cQE(dinosbip$FC[sue]) #default correction factor
cQE(dinosbip$FC[sue], cor = 1.815) #based on eccentricity of the femur

##Estimates of bipedal dinosaurs using phylogeneteically corrected linear and quadratic equations
cQE(dinosbip$FC, equation = "phylocor", cor = dinosbip$cor, quadratic = TRUE, data = dinosbip)

MASSTIMATE documentation built on May 29, 2017, 4:23 p.m.