ISSN 1063-0740, Russian Journal of Marine Biology, 2007, Vol. 33, No. 1, pp. 61–66. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © E.N. Temereva, V.A. Kulikova, 2007, published in Biologiya Morya.
Phoronids are exclusively marine animals with sed-
entary mode of life; they inhabit tubes which they pro-
duce in sand or in a column of stones and mollusk
shells. Almost all known species of phoronids have a
plankton larva, the actinotroch (
). The act-
inotroch was described earlier than the adult forms,
under the species name
The adults, inhabiting the bottom, were revealed and
described later, under the generic name
). The relationships between actinotrochs and adult
phoronids were revealed in 1867 by the Russian scien-
tist Kovalevskii .
Between the description of the ﬁrst phoronid larva
and the studies of Kovalevskii other larvae of phoronids
were described under different species names. At the
same time, new adult forms were also described under
different species names. The relationships between
phoronid larvae and the respective adult animals have
been revealed, for most species, only in the second half
of the 20th century. This is the reason that the species
names of the larvae do not agree with the species names
of the respective adult forms for the taxonomy of
phoronids at the present time. For example,
, the larva described by Mueller ,
corresponds to the adult animal
which was described later by Selys-Longchamps .
Roule, 1896 is the larva of the
Cori, 1889; etc.
Phoronids are distributed worldwide and in some
areas of the World Ocean they exhibit great population
density, reaching 5000 specimens/m
. The larvae of
phoronids live in plankton for 1 to 3 months and also
exhibit great densities in the Black Sea, the Sea of
Japan and the Sea of Okhotsk [1, 2, 5, 9]. The great den-
sity of the larvae makes them important objects during
various plankton studies; therefore, we need to be able
to identify them down to the species level.
During examination of plankton samples collected
in Terpeniya Bay in 2003, we found phoronid larvae
belonging to the species
with the larvae of other species, the larvae of
have been studied in the most detail. However, no
description is available for different stages of larval
The target of this study was to describe the larval
from Terpeniya Bay, Sea
of Okhotsk, and to compare the results with the infor-
mation available from literature.
MATERIAL AND METHODS
During this study we examined plankton samples
collected in Terpeniya Bay (northern coast), in August
2003, with a Juday net, from the surface water layer.
The samples were ﬁxed with a 4% formalin. The larvae
of phoronids revealed in the samples were rinsed from
the ﬁxative in distilled water and stored in 70% alcohol.
Larvae of Phoronids (Phoronida) from Terpeniya Bay
E. N. Temereva
and V. A. Kulikova
Moscow State University, Moscow, 119992 Russia
Institute of Marine Biology, Far East Division, Russian Academy of Sciences, Vladivostok, 690014 Russia
Received September 21, 2006
—Phoronid larvae were found in planktonic samples from the northern coast of Terpeniya Bay. In
some samples, their density was up to 220 specimens/m
. Larval stages having 10, 12, 16, 20, and 22 tentacles
are described. Larvae were identiﬁed as
and belong to the species
Selys-Longchamps, 1903. However, unlike the
larvae described in the literature, the larvae we
found are smaller (not more than 900
m) before metamorphosis and have fewer tentacles (24). They lack
paired vacuolated diverticula of the stomach, which are characteristic of
larvae. However, judging
by all other characters, namely transparency, the absence of coelomic cylinder in the preoral lobe, and the pres-
ence of adult tentacle primordia, one pair of blood cell aggregations, and a pyriform organ, these larvae are sim-
ilar to the previously described larvae of
Adult forms of
were previously found in
Terpeniya Bay and described by Mamkaev (1962) and Emig (1984).
Actinotrocha branchiata, Phoronis muelleri
, Terpeniya Bay.