Diversity and Zoogeography of Rotifera (Monogononta) in a Flood Plain Lake of the Ichilo River, Bolivia, with Notes on Little-Known Species

28 Pages·7.223 MB·English

by  Hendrik Segers Affiliation: Laboratory of Animal Ecology, Zoogeography and Nature Conservation, Department Biology, University of Gent, K. L. Ledeganckstraat 35, B-9000 Gent, Belgium, Niniver L Ferrufino Affiliation: Unidad de Limnología y Recursos Acuáticos, Universidad Mayor de San Simón, Casilla 5263, Cochabamba, Bolivia, Luc de Meester Affiliation: Laboratory of Ecology and Aquaculture, Katholieke Universiteit Leuven, Naamsestraat 59, B-3000 Leuven, Belgium

ROTIFERA FROM AUSTRALIAN INLAND WATERS
VIII. TRICHOCERCIDAE (MONOGONONTA)
BY R. J. SHIEL* & W. KOSTE†
Summary

Diagnostic keys are given to the genera and species of the Australian representatives of the
Rotifera: Monogononta in the family Trichocercidae (Ascomorphella (1 sp.), Elosa (1 sp.) and
Trichocerca (43 spp.)). All species know from Australian waters are described and figured.
Distribution data and ecological information also are given.
KEY WORDS Rotifera, Australia, taxonomic revision, Trichocercidae, Ascomorphella, Elosa,
Trichocerca
Transactions of the Royiil So(,/ety of S. Aust. (1992). ll6(l), 1-27.
ROTIFERA FROM AUSTRALIAN INLAND WATERS
VIII. TRICHOCERCIDAE (MONOGONONTA)
Summary
SHIELR, . J. & KOSTE,W . (1992) Rotifera from Australian inland waters VIII. Trichocercidae (Monogononta).
Trans. R. Soc. S. Aust. 116(1), 1-27, 29 May 1992.
Diagnostic keys are given to the genera and species of the Australian representatives of the Rotifera: Monogononta
in the family Trichocercidae (Ascomorphella (1 sp.), Elosa (1 sp.) and Trichocerca (43 spp.)). All species known
from Australian waters are described and figured. Distribution data and ecological information also are given.
KEY WORDSR otifera, Australia, taxonomic revision, Trichocercidae, Ascomorphella, Elosa, Trichocerca
Introduction Methods of studying Trichocercidae
Taxonomically significant features of trichocercid
There are sporadic systematic references to the
rotifers are detailed in Fig. 1. Preserved (contracted)
occurrence of trichocercid rotifers in Australia (cf.
individuals generally can be identified, however
Shiel & Koste 1979), however a review comparable to
contraction of protruding anterior spines, denticles or
that of Jennings (1903) for North America, or included
folds may vary between individuals. To observe palpar
in Koste (1978) for Europe, is lacking. A thorough
organs and sensors on the corona, living specimens
global revision of the family using modern techniques
are preferable. Trophi examination also is important
(e.g. SEM) is desirable, particularly in view of recent
in species determination (Fig. Ib. c), For example
evidence of species-specificity in rotifer trophi (e.g.
Trichocerca porcellus and T. musculus have similar
Markevitch & Kutikova 1990).
morphology, but differ in trophi. The position of the
Trichocercid rotifers are a common component of
lateral antennae at the front of the striated area is
plankton and littoral microfaunal communities in most
significant. By the addition of Eau de Javelle (KOHCI)
Australian fresh waters. The family includes three
or sodium hypochlorite (NaOCl) the animal is spread
genera: Elosa, recorded from N.S.W. (Murray 1913b);
out and the position of the lateral antenna is
Ascornorphella (A. volvocicola often occurs as an
momentarily clearer; rapid observation is necessary.
inhabitant of Volvox colonies in reservoirs (see Ganf
Important in trophi analysis are the manubria
et al. 1983)) and Trichocerca. Trichocerca is the most
(particularly terminal morphology), direction of the
diverse rotifer genus known from Australia (46 taxa
alulae, number of teeth of unci and rami. Excessive
recorded). Some species may be found in limno- and
exposure to hypochlorite destroys the trophi it can
river plankton, however they reach their greatest -
be neutralised by dilute acetic acid. Toe and body
diversity and abundance in littoral (vegetated) margins,
lengths should be measured. Substyli at the toe bases
especially in billabongs. Up to eight species may
are sometimes stuck together by excretions from foot
coexist in billabongs of the River Murray, where their
glands; in view of apparent variability in number this
morphological andlor behavioural adaptations permit
is unimportant for identification.
effective resource partitioning (Tan & Shiel in press).
Two subgenera of Trichocerca are distinguished on
This paper follows the format of earlier parts (listed
toe morphology. T (Diurella) Bory de St Vincent has
in Koste & Shiel 1990) to review the present status of
toes of similar length or right at least '/3 the length of
the family in Australia, including available ecological
left; T. (s. str.) Lamarck has dissimilar length toes,
information. Where type locality information was not
right never more than '/3 the length of left. We have
available to us, the probable country of origin of the
combined the subgenera in a single dichotomous key,
material is given in parentheses. Very little holotype
but for convenience in comparing figured morphology,
material has been lodged for the Rotifera in general.
the two subgenera are treated separately in the
systematic section. To date 43 species of Trichocerca
have been identified from Australia, most from littoral
vegetation in billabongs or in the open water of
* Murray-Darling Freshwater Research Centre, P.O. Box 921, billabongs or lakes and rivers as incursion species from
Albury, N.S.W., 2640 (to whom reprint requests should marginal vegetation. i? similis occurs commonly in the
be addressed).
t Ludwig-Brill-Strasse 5, Quakenbriick, D-4570, Federal plankton of Murray-Darling reservoirs and rivers (Shiel
Republic of Germany. et al. 1982).