Evolution of Larval Feeding
Evolution of Larval Feeding
1. GW ROUSE (2000a) Bias? What bias? Gain and loss of downstream larval-feeding in animals. Zoologica Scripta 29: 213-236.
2. GW ROUSE (2000b) The epitome of hand waving? Larval feeding and hypotheses of metazoan phylogeny. Evolution and Development 2: 222-233.
3. GW ROUSE (2000c) Polychaetes have evolved feeding larvae several times. Bulletin Marine Science: 67: 391-409.
These three papers present different perspectives resulting from cladistic analyses, based on morphological structures of adults and larva, found in Rouse (1999). The first paper concerns the overall transitions to and from larval feeding in a large group of animals. The second paper discusses how this result affects recent hypotheses of the evolution of animals and the third paper focuses on the evolution of larvae of polychaete annelids.
A classical feeding trochophore larvae from a serpulid polychaete. The results of these papers suggest that this and other kinds of feeding trochophores have evolved a number of times, contrary to traditional thinking.
These three papers use the same set of matrices.
Some changes in terms of homology arguments, and hence scoring in both matrices, from Rouse (1999) are:
A. The character ‘Neurotroch’ was mis-scored for Spionidae and Poecilochaetidae. There is no evidence of a neurotroch in either of these taxa and they are changed from present to absent. Goniadidae was mis-scored as absent for the character 'Telotroch'. Cazaux (1972) clearly shows a telotroch in the larvae of Goniadida emerita.
B. The character Nuchal organs in Rouse and Fauchald (1997) had several mis-scores that are now corrected. Glyceridae, Goniadidae and Paralacydoniidae were all scored 'absent' for nuchal organs by Rouse and Fauchald (1997). In fact nuchal organs are present in glycerids (Whittle and Zahid 1974) and may be present in goniadids. Nuchal organs have also been noted in Paralacydoniidae (Pleijel pers. comm.). The scoring was thus changed to present for the Glyceridae and Paralacydoniidae and to '?' for the Goniadidae.
C. The character ‘Opposed-band larval feeding’ has been removed and is replaced here with a more general character ‘Downstream larval-feeding’. This is scored as a binary character (with a weight of 1) and taxa scored as absent either are lecithotrophic or, in a few cases outlined in the main text, use another form of planktotrophy.
The various matrices can be downloaded from TreeBase. Search for Greg Rouse under author and it is listed as Bias? What bias?
