Morphological Differences between Larvae of the Ciona intestinalis Species Complex: Hints for a Valid Taxonomic Definition of Distinct Species

• DOI: 10.1371/journal.pone.0122879
• Publication Date: 2015-05-08T18:05:14Z
• Authors: Roberta Pennati; Gentile Francesco...; Riccardo Brunetti; Federico Caicci; Fabio Gasparini; Francesca Griggio; Atsuko Sato; Thomas Stach; Sabrina Kaul-Stre...; Carmela Gissi; Lucia Manni
• Keywords: Morphological Analysis; Body plan; Discriminant function analysis; Taxonomic rank

The cosmopolitan ascidian Ciona intestinalis is the most common model species of Tunicata, sister-group Vertebrata, and widely used in developmental biology, genomics evolutionary studies. Recently, molecular studies suggested presence cryptic hidden within C. species, namely type A B. So far, no substantial morphological differences have been identified between individuals belonging to two types. Here we present morphometric, immunohistochemical, histological analyses, as well 3-D reconstructions, late larvae obtained by cross-fertilization experiments molecularly determined B adults, sampled different seasons four localities. Our data point quantitative qualitative trunk shape In particular, exhibit a longer pre-oral lobe, relatively narrower total body length, shorter ocellus-tail distance than larvae. All these were found be statistically significant Discriminant Analysis. Depending on number analyzed parameters, discriminant function was able correctly classify > 93% larvae, with remaining misclassified attributable existence intra-type seasonal variability. No larval observed at level histology immunohistochemical localization peripheral sensory neurons. We conclude that are distinct can distinguished basis morphology data. Since appear valid diagnostic characters, suggest raise both types rank assign them names.