. Bonner zoologische Monographien. Zoology. 42. A B C : Logically possible phylogenetic inteiTelationship of the three presumably mono- phyletic higher taxa of the Chordata. A - No author favoured this possibility, although Salvini-Plawen (1998) claims that light sensitive organs of tunicate larvae are homologous to eyes of craniates, but not to eye structures of cephalochordates (but see Lacalli 1996). B - Atriozoa-Hypothesis (see text). C - Currently favoured phylogeny of the chordates (see and text). 1999 for a conflicting interpretation). With the assumed monophyly of the Chor
. Bonner zoologische Monographien. Zoology. 42. A B C : Logically possible phylogenetic inteiTelationship of the three presumably mono- phyletic higher taxa of the Chordata. A - No author favoured this possibility, although Salvini-Plawen (1998) claims that light sensitive organs of tunicate larvae are homologous to eyes of craniates, but not to eye structures of cephalochordates (but see Lacalli 1996). B - Atriozoa-Hypothesis (see text). C - Currently favoured phylogeny of the chordates (see and text). 1999 for a conflicting interpretation). With the assumed monophyly of the Chordata and of the three subgroups within the Chordata, i. e., the Tunicata, the Cephalochordata, and the Craniata, only three possibilities for the interrelations- hips between these taxa exist (). Since a phylogenetic framework is crucial for the interpretation of evolutionary changes, I provide a short summary of the argumentation supporting the current- ly favored hypothesis () based primarily on morphological data. It is obvious that all conflicting hypotheses have to account for the shared similarities discussed below between the Cephalochordata and Craniata. Although Hennig (1984) is not an original publication on the subject of chordate phylogeny it is cited because of its phylogenetic perspective on previously des- cribed characters and its consistent phylogenetic interpretation of these characters. • The most obvious and superficially visible features common to cephalochorda- tes and craniates are the segmentally arranged muscle blocks of the trunk. It has been debated whether the muscular band of miniature muscle cells in the tail of tunicates represents a segmental arrangement comparable to that found in the Notochordata (e. g., Berril 1955, Jollie 1973). In any case, repeated lateral myo- meres separated by connective tissue with a dorsal anterior angle ("chevron shape") are unique to the Notochordata and can, in combination with the other evid
Size: 2938px × 851px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjectzoology