PhD Arthur Decae 2010 - Ghent Ecology - Universiteit Gent

TNT-analysis of reduced data-set (64 taxa, 27 characters, appendix Table 6)
Four runs of cladistic analyses (against four different reference groups, see above) on a
reduced data-matrix (Appendix Table 5) using the TNT-program confirmed our MDS results
by showing a basic division of Nemesia in two distinct sub-generic clades (Appendix Figs.18-
21). Detailed information on parameter settings for TNT-analysis and results produced are
summarized in Table 2.
For convenience, and based on Simon’s 1914 terminology for subdividing Nemesia, the two
sub-generic lineages are provisionally named Pronemesia and Holonemesia (Holonemesia for
Simon’s rather impractical term Nemesia sensu stricto). Morphologically the two sub-generic
groups are primarily distinguished on characters of the PMS; characters 14, 15, 16, 17,
(Appendix Character List 1) in our data-matrix Table 4 (see also Figs. 3, 15, 16). The species
composition of Pronemesia and Holonemesia found was to be constant in all four TNT-runs
(see Appendix Table 6). The distribution of Pronemesia and Holonemesia, as far as it can be
read from the limited information in our data-set, is shown in Fig. 5. Pronemesia appears to
have its centre of distribution on the Iberian Peninsula and around the western Mediterranean.
Holonemesia seems primarily distributed in the Central Mediterranean extending both far to
the East into Greece and to the West into southeastern Spain. Although not fully resolved, all
four cladograms studied (Figs. 18-21 give strict consensus cladograms of 10 to 40 shortest
trees retained by the program) show further subdivisions of Pronemesia and Holonemesia in
several distinct and coherent clades.
Outgroup Best
Hit
Total
Rearrangements
TBR
Score
Tree
Length
Random
Seed
n.Min
Steps
n.Max
Steps
I. machadoi 1x 12173886 7.772315 93 7252 24 303
B. denieri 4x 9461300 8.07192 97 195 26 304
Hypothetical 000 7x 1288030 7.66961 93 2491 26 303
Hypothetical 111 1x 13764388 8.99643 100 18487 24 310
Table 4 Score results of traditional search analysis (TNT) using implied weighting (default
settings) on four different reference groups and variable basic parameters settings.
Pronemesia Simon 1914 (Figs. 3, 4, 5, 7, 8 & 16)
The subgenus Pronemesia is reestablished on the basis of characteristic spinneret morphology
(Figs. 3 & 16) after Simon (1914: pg. 3). Simon used spine-patters and characters of the
scopulae, embolus and burrow structure to arrive at a more restricted characterization of
Pronemesia that pertained only to the Caementaria-Group (see below). As diagnosed here
Pronemesia relates to a highly diverse subgenus of Nemesia occurring around the western
Mediterranean only.
Within Pronemesia two coherent supra-specific groups appear to be consistently present in all
four cladograms (Fig. 4, see also Appendix figs. 18-21). One apparently stable group of four
species (terminals) is present in all analysis results. The clade is here denoted as the Algeria-
Group. The key, and supposedly apomorphic, character defining the Algeria-Group
(Character List 1, char. [5]) is the presence of two serrated ridges placed on opposite sites on
the embolus (Figs. 5 & 7). The fact that no discriminating characters were found between N.
sp.bejaia and N. sp.boumerdes might indicate that these are conspecific and that the Algeria-
Group in our sample is present with three species.