CULEOLUS HERDMANI SLUITER, 1904 (ASCIDIACEA, TUNICATA) FROM THE NORTHWESTERN AUSTRALIAN CONTINENTAL SLOPE WITH AN OVERVIEW OF THE GENUS

1 Pages·2003·0.34 MB·

by  Patricia Kott

Recordsofthe WesternAustralianMuseum21: 63-70 (2002).
Culeolus herdmani Sluiter, 1904 (Ascidiacea, Tunicata) from the
northwestern Australian continental slope with an overview of the genus
PatriciaKott
QueenslandMuseum,POBox3300,SouthBrisbaneQueensland4101,Australia
Abstract-ThirteenspecimensofCuleolusherdmaniSluiter, 1904 (Ascidiacea,
Tunicata) taken at 3 locations on the northwestern Australian continental
slope (between 408m and 550m and 14°16.8'S and 16°09.5'S) are the first
recordsofthisgenusfromAustralianwaters.Thespeciesisoneof7Culeolus
spp. recorded at depths of 1800m or less. The newly recorded specimens
generallyresemblethetypespecimenandothersfromthePhilippines,Japan
and New Caledonia, although there are some differences in the number of
branchial folds,length ofstalk, presenceofa longventral branchial tentacle
and mid-ventral papillary crest and interruption of the postero-lateral
papillarycrest overthe dorsal mid-line. Included in this accountisa key to
the species of the genus and a table summarising their distribution and
characters
INTRODUCTION on species relationships can be obtained from the
The genus Culeolus (Pyuridae, Stolidobranchia) gonads,althoughinsomecasesthesehavenotbeen
waserectedbyHerdman (1881) for5species taken described;andbecauserelativelyfewspecimensare
by HMS Challenger from depths of4000 to 5798 m available in most of the known taxa, variations in
inthePacific(offJapan,inthetropicsandtheSouth the number and arrangement of the gonads and
Pacific) and the Atlantic Oceans. The genus is theirsubdivisionsarenotwelldocumented.
characteristic of abyssal ascidians, having an open Unlike most abyssal species, Culeolus spp.
meshworkoflongitudinalandtransversevesselsin generallyhave arelatively restricted known range,
thebranchial sac and lacking stigmata. All species with few exceptions being known from either the
have a narrow stalk that most often is long and northernorsouthernAtlanticorPacificOceans, the
wiryandisattachedattheanteriorendofthebody tropicalPacific orthe SouthernOcean. The present
as in other stalked forms (see Kott 1989). The speciesisknownmainlyfromthecontinentalslopes
branchial aperture is antero-dorsal and the atrial in the western Pacific. The only other species
aperture alarge transversepostero-dorsalopening. recorded only from slope locations are C. gigas
Most of the species in the genus have a crest of Sluiter, 1904, C. quadrula Sluiter, 1904, and C.
enlarged papillae around the posterior end of the thysanotus Sluiter, 1904 from Indonesia; C. caudatus
body,sometimesenclosingtheatrialaperturebutin Monniot&Monniot, 1991 fromoffNewCaledonia;
other species interrupted over the dorsal surface C. xuyville-thomsoni Herdman, 1881 from the South
and terminatingeachsideofthe atrialaperture. As Pacific; and C. sluiteri Ritter, 1913 from off the
inotherPyuridae,branchialtentaclesarebranched, Aleutians. Allotherspeciesofthe21 knowninthis
thebranchialsachas5to7folds and thegutforms genus are recorded from 2000m or more (up to
the usual loop and has liver lobules in the pyloric 7000m in the Kurile Trench: C. robustus
region. Gonads arerelativelylong,sometimes with Vinogradova,1970).
thetestisfolliclesdividedintoclumpsonthemesial
surface of the ovarian tube but occasionally the TAXONOMY
wholegonaddividedintohermaphroditeblocks as
in Pyura and Microcosmus. There are seldom more
than3gonadsperside.Occasionallyoneormoreof CuleolusherdmaniSluiter,1904
the gonads on the left side ofthebody are outside Culeolus herdmani Sluiter, 1904: 105. Van Name,
the gut loop. Antero-posteriorly flattened languets 1918: 83. Tokioka, 1953: 289. Millar, 1975: 319.
are at thejimctions of the transverse vessels along Monniot&Monniot,1991:421.
thedorsalmid-line.
Thespeciesinthisgenusarerelativelyuniformin Distribution
externalappearance.Distinctionsoftenarebasedon
the form ofpapillaeboth on the surface and in the NewRecords
postero-lateral papillary crest. Useful information WesternAustralian (NW ofCollier Bay, 14°7.5'S;