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Sister species within Triops cancriformis • M. Korn et al.

Fig. 5 A–D. Quantification of a selection of the morphological variability of Triops cancriformis haplotype groups, whereby these were defined as
subgroups of sequences sharing diagnostic sites, without consideration of singletons (the population from Girona, northern Spain, is treated as
a separate haplotype group here to investigate a nonconcordance in the present classification of this population as T. c. simplex and genetic data,
which suggests its affiliation to T. c. cancriformis). For details on haplotype groups see Table 1 and Appendix 1. The present nomenclature is
indicated in the graphs, above the data points. Note the different scales. Error bars: 95% confidence intervals. —A. The ratio of furcal spine
length to total telson length (including the spine). —B. The number of apodous segments in females. —C, D. The square root transformed
0.5
numbers (x ) of dorsal carina spines of —C. A subset of haplotype groups used for statistics —D. All haplotype groups included.
Abbreviations: T.c.s, Triops c. simplex; T.c.c, T. c. cancriformis; T.c.m, T. c. mauritanicus; n.d., not defined (unusual combination of key
morphological characters).

of the populations studied (such a reduction was never to four spines in Moroccan T. c. simplex, resulting in mean
observed in Iberian T. c. mauritanicus specimens). Thus, care values not markedly different to that of the northern Spanish
should be taken that the counts of dorsal carina spines will population (Fig. 5C,D). The intermediate population from
not simply be a function of quality or magnification of the Tunisia was found to have 0–28 carinal spines, a number also
microscope used. within the range we found for typical T. c. cancriformis. In this
In Tunisia, Sicily and on Ustica Island we found three population, spines are arranged in a regular row in front of
apparently male-less populations of T. cancriformis (‘Sicilian’ the terminal spine, which is typical for T. c. mauritanicus, but
haplotype) that almost completely lack carina spines. Only most of the spines are very small, even smaller than the most
5% of these specimens (n = 57) had dorsal carina spines and reduced forms found among Moroccan T. c. mauritanicus.
in one case, the single spine present was almost completely
reduced. Most surprisingly, the morphological reinvestiga- Number of apodous abdominal segments in females. This character
tion of northern Spanish material revealed that there is a clearly separates typical T. c. cancriformis from T. c. simplex, the
rather high percentage of specimens with spines in this intermediate form and the northern Spanish population
population (50%, n = 22), although the spines are mostly very (P < 0.05, Tukey post-hoc test, see Appendix 2A), the latter
small. Spines are arranged at irregular distances, all close to showing the highest values (Fig. 5B). Most of the T. c. mauri-
the terminal spine. According to descriptions given in the tanicus haplotype groups have intermediate mean values.
literature, T. c. simplex is diagnosed as lacking these carinal There are no clear differences in the number of apodous
spines completely (Ghigi 1921; Longhurst 1955). In the segments among populations of T. c. mauritanicus (Fig. 5B),
northern Spanish population, the number of spines was but in Moroccan haplotype groups, there seems to be a
found to range from 0 to 14, which is well within the range tendency towards a higher number of apodous segments
we found for typical T. c. cancriformis. towards haplotype groups found in the south. The values for
We even found specimens with up to seven very small carina T. c. mauritanicus also almost completely encompass those of
spines in a sample of typical T. c. simplex from Tunisia, and up the other two subspecies.

312 Zoologica Scripta, 35, 4, July 2006, pp301–322 • © 2006 The Authors. Journal compilation © 2006 The Norwegian Academy of Science and Letters