Continuous characters analyzed as such

By Pablo A. Goloboff, C. Mattoni, A. S. Quinteros. Cladistics, 2006

376 citations recorded by the source corpus.

Quantitative and continuous characters have rarely been included in cladistic analyses of morphological data; when included, they have always been discretized, using a variety of ad hoc methods. As continuous characters are typically additive, they can be optimized with well known algorithms, so that with a proper implementation they could be easily analyzed without discretization. The program TNT has recently incorporated algorithms for analysis of continuous characters. One of the problems that has been pointed out with existing methods for discretization is that they can attribute different states to terminals that do not differ significantly—or vice versa. With the implementation in TNT, this problem is diminished (or avoided entirely) by simply assigning to each terminal a range that goes from the mean minus one (or two) SE to the mean plus one (or two) SE; given normal distributions, terminals that do not overlap thus differ significantly (more significantly if using more than 1 SE). Three real data sets (for scorpions, spiders and lizards) comprising both discrete and quantitative characters are analyzed to study the performance of continuous characters. One of the matrices has a reduced number of continuous characters, and thus continuous characters analyzed by themselves produce only poorly resolved trees; the support for many of the groups supported by the discrete characters alone, however, is increased when the continuous characters are added to the analysis. The other two matrices have larger numbers of continuous characters, so that the results of separate analyses for the discrete and the continuous characters can be more meaningfully compared. In both cases, the continuous characters (analyzed alone) result in trees that are relatively similar to the trees produced by the discrete characters alone. These results suggest that continuous characters carry indeed phylogenetic information, and that (if they have been observed) there is no real reason to exclude them from the analysis.

Subfields: Global and Planetary Change, Paleontology

View Paper: https://www.semanticscholar.org/paper/fe7a59e2c3c58e8ab13ade4895af45999094b734

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Citations in the corpus

Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms (2013, methodology): “All tree searches, identification of ‘wild card’ taxa, and tests of topological robustness were carried out in TNT (Goloboff et al., 2008).”
Morphology, phylogeny and taxonomy of South American bothropoid pitvipers (Serpentes, Viperidae) (2012, methodology): “We followed Goloboff et al. (2006), who demonstrated that when continuous characters are treated as simply additive characters, they can be optimised with algorithms such as Farris (1970), implemented in TNT program (Goloboff et al. 2008a), and analysed without discretisation.”
Phylogenetic Relationships of Oryzomine Rodents (Muroidea: Sigmodontinae): Separate and Combined Analyses of Morphological and Molecular Data (2006, methodology): “Lengths, ratios, and other quantitative traits were not included because no proper method is currently available for coding continuous characters in a parsimonyanalytic context (but see Goloboff et al., 2004).”
A comprehensive taxonomic revision of Dicynodon (Therapsida, Anomodontia) and its implications for dicynodont phylogeny, biogeography, and biostratigraphy (2011, methodology): “…1984; Thorpe, 1984; Archie, 1985; Baum, 1988; Felsenstein, 1988, 2002; Goldman, 1988; Chappill, 1989; Thiele, 1993; Miller and Coyle, 1996; Straight et al., 1996; Sosa and De Luna, 1998; Swiderski et al., 1998; Wiens, 2001; Guerrero et al., 2003; Garcia-Cruz and Sosa, 2006; Goloboff et al., 2006).”
TNT version 1.5, including a full implementation of phylogenetic morphometrics (2016, background): “Mongiardino Koch et al. (2014) showed that, although the use of implied weighting decreases the effect of differences in scaling (as ﬁrst proposed by Goloboff et al., 2006), the use of a uniform scaling is more effective at making the contributions of different characters more even.”
TNT, a free program for phylogenetic analysis (2008, background): “Despite the fact that continuous characters are so common in morphological data sets, all other programs for phylogenetic analysis require that continuous characters be forced into characters with discrete states; TNT instead optimizes continuous characters as such (Goloboff et al., 2006).”
The Morphology And Phylogeny Of Dionychan Spiders (Araneae: Araneomorphae) (2014, background): “’’ This cost regime follows all the methodological literature on continuous characters (e.g., Wiens, 2001; Goloboff et al., 2006).”