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body or in the oral region ; “overproduction” dur-
ing stomatogenesis appears to be a source of some 
of these supernumeraries (e.g. in the parakinetal
stomatogenesis of Tetrahymena ); in some cases, 
they may be erratic kinetosomes and/or parts of an 
anlage and/or parts of a vestige ; might also include 
cases of intercalated kineties , whole or partial, 
which involve a line or file of several or even many 
additional somatic kinetosomes. 
Supraepiplasmic Microtubules : microtubules, 
single or in ribbons, lying above the epiplasm and 
coursing along parallel to the outer surface of the 
Suture Lines : simply folds or creases in the pel-
licle ; preferably associated with the important 
concept of the secant system , the converging of 
kineties from different areas of the surface of the 
ciliate onto suture lines forming a pattern con-
sistent within a given taxonomic group; see also 
Postoral Suture and Preoral Suture . 
Swarmer : dispersive form in the life cycle of a 
number of ciliates; see Larval Form . 
Symbiont : so-called dependent member or partner, 
except in cases of mutualism , of a pair of organisms 
exhibiting symbiosis , the other being the host ; see 
Commensalism , Mutualism , and Parasitism . 
Symbiosis : the living together, more or less 
intimately and contiguously, of two organisms, 
the host and the symbiont ; see Commensalism , 
Mutualism , and Parasitism.
Symbiotic (adj.): see Symbiosis . 
Symmetrogenic Fission : type of fission , generally 
longitudinal, of a parental form in such a manner 
that the two filial products are, in effect, mirror 
images of one another with respect to principal 
structures; typical of non-ciliate protozoa; compare 
to Homothetogenic Fission (Fig. 2.11Ab). 
Symphoriont : symbiont exhibiting a kind of com-
mensalism in which the host , usually via its 
56 2. Glossary of Terms and Concepts Useful in Ciliate Systematics
integument, appears to serve solely as a convenient 
substratum for attachment of the typically stalked 
sessile ciliate; not always clearly distinguishable 
from other degrees of intimacy between hosts and 
their associated ectocommensals, but it represents 
a convenient term with reference to many peritrich 
and suctorian species; not generally used, by con-
vention, for parasitic ciliates exhibiting a phoront
stage, which, however, can really be functionally 
very similar; see Phoront . 
Symplesiomorphic : shared ancestral homologous 
character ; compare with Synapomorphic . 
Synapomorphic : shared derived homologous 
character or shared apomorphies ; used to unam-
biguously define a clade or monophyletic group. 
Synciliary Ciliature : see Syncilium . 
Syncilium (pl. Syncilia ): a group of closely packed 
somatic cilia forming a special tuft exhibiting 
considerable internal coherence and arising from 
a packet of kinetosomes that are interconnected at 
their proximal ends with other syncilia; character-
istic of entodiniomorphid vestibuliferans , syncilia 
were formerly called membranelles , with recogni-
tion of adoral and dorsal zones ; they also occur as 
part of the caudalia present at the posterior end of 
the body of certain cycloposthiid entodiniomor-
phids ; see Polybrachykinety (Syn, Fig. 2.5Af). 
Syndesmogamy : a conjugation found only in 
 apostomes during which two trophonts encyst 
together and undergo preconjugation division by 
linear palintomy , after which the filial products
fuse and conjugate; also called zygopalintomy. 
Syngamy : fusion of the gametic nuclei during con-
jugation ; also called fertilization or karyogamy. 
Syngen : complex of two or more sexually com-
patible mating types (e.g., in Paramecium or 
Tetrahymena ), formerly known as “ varieties ”; long 
recognized as reproductively isolated biological 
units, hence biological species ; see Variety . 
Synhymenium : single apparent “membrane” 
resulting from an uninterrupted joining of the 
pavés of the frange of some nassophoreans . 
Synkaryon : nucleus formed by fusion of two hap-
loid gametic nuclei or pronuclei in the sexual phe-
nomena of conjugation or autogamy ; its division 
products differentiate into the new diploid micro-
nuclei and the typically polyploid macronuclei ; see 
Zygotic Nucleus . 
Synonym : one or two or more names applied to 
the same organism or taxon; the oldest or earli-
est published is the senior synonym, which name 
usually must prevail; the later or younger of two is 
the junior synonym; an objective synonym is one 
based on study of the same material as the original 
describer, whereas a subjective synonym is based 
on material that is different but alleged to represent 
the original organism or taxon; see Homonym , 
Rule of Priority . 
Système Sécant : see Secant System . 
Systole : see Contractile Vacuole . 
Tactile Cilium (pl. Cilia ): see Sensory Bristle and 
Thigmotactic Cilia . 
Tail : generalized term, variously used in non-
specific ways; a caudal appendage, ranging from 
specialized cilia or mucous filaments to narrow and 
lengthy extensions of the body proper. 
Tangential Fibers : see preferred term, Transverse 
Microtubules . 
Tastcilie (pl. Tastcilien ): see Sensory Bristle(s) . 
Tectin Granules : small, subpellicularly located 
bodies involved in secretion of a substance, prob-
ably mucopolysaccharide in nature, used to con-
struct the lorica in a number of ciliates, especially 
among the sessiline peritrichs . 
Teeth : nonspecific term; but also, perhaps unwisely, 
used to describe the nematodesmal capitula char-
acteristic of some dysteriid cyrtophorines ; see 
Capitulum . 
Tela Corticalis : synonym of lamina corticalis . 
Telokinetal : type of stomatogenesis in which forma-
tion of the new oral structures occurs by direct involve-
ment either of kinetosomes at the anterior extremities 
of all or some of the encircling somatic kineties or of 
kinetosomes comprising the short kinetofragments
available in the vicinity; see Cryptotelokinetal,
Holotelokinetal, Intertelokinetal, Merotelokinetal,
Monotelokinetal , and Pleurotelokinetal (Fig. 
2.11Da, 2.11Db). 
Glossary 57
Teloparakinetal : parakinetal stomatogenesis in 
which the oral anlage originates by proliferation 
of kinetosomes at the anterior ends of postoral 
kinetofragments and at the “broken ends” of bipo-
lar somatic kineties ; found in ophryoglenids . 
Telotroch : migratory free-swimming larval form , 
especially in the life cycle of sessiline peritrichs ; 
trophonts of mobiline peritrichs are sometimes 
thought of as permanent telotrochs exhibiting neo-
teny (Fig. 2.11B). 
TEM : transmission electron microscopy. 
Temporary Conjugation : fusion with subse-
quent separation of the members of the conjugat-
ing pair; the mode of conjugation shown by most 
ciliates except peritrichs , chonotrichs , and some 
 suctorians , which show total conjugation ; see 
Conjugation . 
Tentacle : tubular extension of or projection from 
the surface, of several different and probably non-
homologous kinds, typically supported by micro-
tubular ribbons : (1) suctorial tentacle , the (only) 
ingestatory apparatus in suctorians; (2) prehensile 
tentacle , a non-ingestatory structure present in 
some suctorians , solely for prey capture; (3) the 
short, non-extensible, apical sucking tube of rhyn-
chodids and grossglockneriid colpodeans ; (4) the 
non-suctorial but highly extensible and retractable 
prey-capturing organelle of such unusual hapto-
rians as Actinobolina , composed of microtubular 
arrays often enclosing a prominent toxicyst and 
found in abundance, over the surface of the body; 
and (5) scattered other projections, lobes, or palps, 
and the like, which are or have been occasionally 
referred to by the term “tentacle”, but properly 
excluding any proboscis (Fig. 2.10). 
Tentaculoid : small finger-like extensions of the