| Title | On the reality and recognisability of asexual organisms: morphological analysis of the masticatory apparatus of bdelloid rotifers |
| Abstract | Species concepts and definitions have been a long-standing debate in evolutionary biology since before Darwin, and almost all proposed solutions are based upon grouping and clustering, with species conceived as somehow biological distinct entities, originated and maintained mainly by reproductive isolation. Lacking reproductive exchange, asexual organisms such as bdelloid rotifers, the best-supported clade of so-called 'ancient asexuals', pose an interesting challenge to debates over the reality of species. However, few data are available on bdelloid rotifers. The only evidence has been that bdelloid species have been more consistently recognised than in their sister sexual group, the monogonont rotifers, across successive taxonomic treatments, but this is confounded by the much lesser degree of taxonomic interest in bdelloids. We applied geometric morphometrics analyses on shape and size of hard masticatory pieces, named trophi, of 1420 bdelloids, belonging to 48 populations of eight traditional species, to test the hypothesis of recognisability of bdelloids. Our morphological analysis confirms that traditional bdelloid species are separated distinct entities, possessing trophi morphologies divided by gaps between taxa, similar to patterns of morphological features in sexually reproducing organisms. In common with most microscopic understudied organisms, bdelloid rotifers harbour much previously undescribed diversity: we found significant differences in trophi morphology within traditional species, revealing the existence of cryptic taxa, similar to those also found in facultatively sexual monogonont rotifers. We confirm that recognisability in bdelloids is not qualitatively different from other small understudied animals such as monogononts, and that sexual versus asexual reproduction does not lead to differences in morphological diversity patterns, as previously suggested based on interpretation of taxonomic revisions. |
| Source | Zoologica scripta 36 (4), pp. 361–370 |
| Journal | Zoologica scripta |
| Editor | Blackwell, Oxford, Regno Unito |
| Year | 2007 |
| Type | Articolo in rivista |
| DOI | 10.1111/j.1463-6409.2007.00281.x |
| Authors | Fontaneto, Diego; Herniou, Elisabeth A.; Barraclough, Timothy G.; Ricci, Claudia; Melone, Giulio |
| Text | 283709 2007 10.1111/j.1463 6409.2007.00281.x ISI Web of Science WOS 000247441100007 On the reality and recognisability of asexual organisms morphological analysis of the masticatory apparatus of bdelloid rotifers Fontaneto, Diego; Herniou, Elisabeth A.; Barraclough, Timothy G.; Ricci, Claudia; Melone, Giulio University of Milan; Imperial College London; Royal Botanic Gardens, Kew Species concepts and definitions have been a long standing debate in evolutionary biology since before Darwin, and almost all proposed solutions are based upon grouping and clustering, with species conceived as somehow biological distinct entities, originated and maintained mainly by reproductive isolation. Lacking reproductive exchange, asexual organisms such as bdelloid rotifers, the best supported clade of so called ancient asexuals , pose an interesting challenge to debates over the reality of species. However, few data are available on bdelloid rotifers. The only evidence has been that bdelloid species have been more consistently recognised than in their sister sexual group, the monogonont rotifers, across successive taxonomic treatments, but this is confounded by the much lesser degree of taxonomic interest in bdelloids. We applied geometric morphometrics analyses on shape and size of hard masticatory pieces, named trophi, of 1420 bdelloids, belonging to 48 populations of eight traditional species, to test the hypothesis of recognisability of bdelloids. Our morphological analysis confirms that traditional bdelloid species are separated distinct entities, possessing trophi morphologies divided by gaps between taxa, similar to patterns of morphological features in sexually reproducing organisms. In common with most microscopic understudied organisms, bdelloid rotifers harbour much previously undescribed diversity we found significant differences in trophi morphology within traditional species, revealing the existence of cryptic taxa, similar to those also found in facultatively sexual monogonont rotifers. We confirm that recognisability in bdelloids is not qualitatively different from other small understudied animals such as monogononts, and that sexual versus asexual reproduction does not lead to differences in morphological diversity patterns, as previously suggested based on interpretation of taxonomic revisions. 36 Articolo in rivista Blackwell 0300 3256 Zoologica scripta Zoologica scripta Zool. scr. Zoologica scripta. diego.fontaneto FONTANETO DIEGO |
