Abstract
39
How did the last common
ancestor of the hypotrichs (Ciliophora, Spirotricha) look like?
BERGER Helmut; Consulting
Engineering Office for Ecology, Radetzkystraße 10, 5020
Salzburg, Austria; E-mail: office@protozoology.com
The Hypotricha Stein (= Stichotrichia
Small & Lynn) are a major group of the spirotrichs. The knowledge
of the ground-pattern (= ground-plan) of an evolutionary unit
is of fundamental importance for the establishment of a phylogenetic
system. This pattern is the combination of all features (e.g.,
morphological, ontogenetic, ecological, molecular) of the last
common ancestor (stem-species) from which a monophylum evolved,
that is, it is summary of apomorphies and more or less young
plesiomorphies. Some supposed apomorphies of the Hypotricha are:
(1) 18 frontal-ventral-transverse cirri; (2) three dorsal kineties;
(3) parental somatic ciliature completely replaced during cell
division. Some plesiomorphies of the hypotrichs are: (1) cirri
present; (2) body dorsoventrally flattened; (3) body flexible;
(4) frontal-ventral-transverse cirri originate from six anlagen;
(5) caudal cirri present; (6) cortical granules present; (7)
lack of kinetodesmal fibres in interphasic specimens; (8) benthic;
(9) telomeric repeat sequence TTTTGGGG. For details, see Monographs
of hypotrichs by Berger (1999; Monographiae Biol. 78:1-1080;
oxytrichids),
Berger (2006; Monographiae Biol. 85: 1-1303; urostyloids), and Berger (2008; Monographiae
Biol., in press; amphisiellids).
The financial support of the Austrian Science Fund (FWF; Project P-20569-B17) is greatly acknowledged.
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Keywords: Alveolata, apomorphy, Ciliophora, ciliates,
evolution, ground pattern, Grundmuster, Hypotrichia, Hypotrichida,
letzter gemeinsamer, molecular biology, phylogeny, plesiomorphy,
review, Spirotricha, spirotricha, stem line, Vorfahre
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Dr Helmut BERGER
Consulting Engineering
Office for Ecology - Technisches Büro für Ökologie
Radetzkystrasse 10, 5020
Salzburg, Austria, Europe
Phone +43-(0)662-432538; Fax +43-(0)662-443139; email office@protozoology.com;
http://www.protozoology.com |