Hydroids of the BANZARE expeditions, 1929 – 1931: the family Haleciidae (Hydrozoa, Leptothecata) from the Australian Antarctic Territory

2008·8.1 MB·English

by  Jeanette E Watson

MemoirsofMuseumVictoria65: 165-178(2008)
ISSN 1447-2546(Print) 1447-2554(On-line)
http://www.museum.vic.gov.au/memoirs/index.asp
Hydroids ofthe BANZARE expeditions, 1929 - 1931: the family Haleciidae
(Hydrozoa, Leptothecata) from the Australian Antarctic Territory
JeanetteE. Watson
HonoraryResearchAssociate,MarineBiology,MuseumVictoria,GPOBox666E,Melbourne3001,Victoria,Australia
([email protected])
Abstract Watson,J.E.2008.HydroidsoftheBANZAREexpeditions,1929-1931:thefamilyHaleciidae(Hydrozoa,Leptothecata)
fromtheAustralianAntarcticTerritory.MemoirsofMuseumVictoria65: 165-178.
The BANZARE Expeditions (British,Australian, New Zealand,Antarctic Research Expeditions) 1929 - 1931
sampledthemarinebenthosintheSouthernOcean,attheKerguelenIslands,HeardIsland,MacquarieIsland,andsouth-
westofTasmaniaandalongthecoastoftheAustralianAntarcticTerritory.Fortysixstationsatdepthsof2-640mwere
occupiedalongtheAustralianAntarcticTerritorycoast.EightspeciesofHaleciumincludingfivenewandHydrodendron
arboreumwerefoundandrecordedfromeightstations.
Keywords BANZAREExpeditions(1929-1931),AustralianAntarcticTerritory,familyHaleciidae.
Introduction senttotheNationalMuseumofVictoria(nowMuseumVictoria)
TheBANZAREExpeditions(British,Australian,NewZealand, BinMMNelHbourne for identification. A difficulty arising from the
reference numbering system has been determining
AntarcticResearchExpeditions) 1929-1931,ledbySirDouglas whether several microslides fromthe same station but labelled
Mawson,mademajorcollectionsbydredgingsfromtheresearch with differentBMNHreference numbers arefromthe same, or
vesselDiscoveryinseveralgeographicallocalities:theSouthern from different colonies. As no information on allocation of
Ocean from SouthAfrica to WesternAustralia, the Kerguelen referencenumberswasprovidedbytheBMNH,itisassumedin
Islands,HeardIsland,MacquarieIsland,south-westofTasmania this reportthat species with consecutive reference numbers but
andalongthecoastoftheAustralianAntarcticTerritory. under the same station number relate to the same colony. To
Forty six stations were occupied along the Australian reduceconfusiontheBMNHreferencenumbershavethusbeen
AntarcticTerritory coastand samples collectedusingvarious abandoned andthe material describedinthis reportis provided
tmraadwlesitnosdheapltlhosw6w4a0temr;2smomedeecpo.asTtahlechoylldercotiidoncsoltloecwteiroenawlasso withSaomMeusoefuthmeVpircetsoeriraverdegmiastterratiiaolninsunmobwerfr(agNilMe;VfFu)r.thermore,
originally deposited in the British Museum, Natural History many ofthe microslides prepared by the BMNH were treated
(BMNH), London. There, preserved material was sorted with a stain which, over the years, has darkened to almost
during the 1960s and microslide mounts prepared. A small opaque green. Re-mounting of this opaque material has not
amountofmaterialleftoverfromtheearlierAAE(Australian beenundertakenbeingtootime-consumingandlikelytodestroy
Antarctic Expedition) 1911-1914 was also incorporated into alreadyfragilespecimens.Forthisstudydescriptionshavebeen
theBANZAREcollectionas StationNo. 1785(seeTable 1). made from those BMNH microslides in good condition and
The entire BANZARE hydroid collection comprises more from preserved material in temporary glycerol mounts and
than 200 jars and vials of preserved material and some 1500 stainedwithBengalRose.
microslides.Foreaseofstudythecollectionwasdividedintothe This paper examines the Antarctic Family Haleciidae
major geographical localities mentioned above. The Antarctic collected from the coast of the Australian Antarctic Territory.
partofthecollectioncomprisessome32jarsofbulksamples,83 EightspeciesofHalecium(includingfivenew) andonespecies
tubesofpreservedmaterialandsome250microslidepreparations ofHydrodendronaredescribed.The greatestnumberofrecords
SampleswereoriginallyprovidedwithaBANZAREfieldstation oftheHaleciidaewerefromstationsoffPrincessElizabethLand
number (eg. Station 105) by the expedition and later at the from60°-80°E(Figure 1,Table 1).Themostabundantspeciesin
BMNHareferencenumberwasadded(eg. Station 105,BMNH thecollectionwereHaleciumbanzaresp.nov.andHydrodendron
Hydr.No.711/6).Afewprovisionalidentificationsweremadeat arboreum, eachofwhichoccurredatfourstations,followedby
the time by Dr W. J. Rees in the BMNH but no reports were Halecium delicatulum, recorded from three stations. All other
prepared.In 1970stheentireBANZAREhydroidcollectionwas specieswererecoveredfromonlyoneortwostations.
166 JeanetteE.Watson
Table 1.StationRecordsofHaleciidae
StationNo. Lat.South Long.East Depthm Dredgetype RemarksinDiscovery’sLog
34 66° 21' 58° 50' 603 DRL Noinformation
40 66° 12' 49°37' 300 TML Goodhaul
41 65°48' 53° 16' 209 TML Abundanthaul;heavypackice
88 67° 00' 142°36' 4-13 DRS CommonwealthBay;amongkelp
97 65° 10' o00o to 474 DRL Noinformation
98 65° 07' 107° 29' 502 DRL Noinformation
103 67° 03' 74° 29' 437 DRL Noinformation
105 67°46' 67° 03' 163 DRL Nearglacier,MacRobertsonLand
107 66°45' 62° 03' 210 DRL AdjacenttolargeIcebergs
17851 - - 45 unknown Noinformation
Note1: Station 1785wasoccupiedinCommonwealthBayduringtheAustralianAntarcticExpedition,1911 - 1914. Station88was
occupiedatCapeDenisoninCommonwealthBayduringthe 1931 partoftheBANZAREexpedition.
HaleciumantarcticumVanhoffen, 1910
CT
Figure2A-C
Halecium antarcticum Vanhoffen, 1910: 317, fig. 34.- Billard,
1914:7,fig.5.-Totton, 1930: 144,fig.4.-Broch, 1948,28:7.-Naumov
andStepanjants, 1958:57-Blanco, 1984: 294,figs8-13,pis.4-5.
Material examined. NMV F147447, Station 107, two microslides
NMV
displaying branch fragments and a preserved fertile colony.
F147448, Station 107, one microslide displaying branch fragments.
NMV
F147449, Station 1785, one microslide displaying two small
branchfragments.
mm
Description. Fertile colony originally at least 40 high.
Hydrorhizareptanton sponge; stolonstubular, rugose, loosely
adherenttosubstrate.
Shorterstemsmonosiphonic;stemsbeginningwithseveral
broadbasalannulationsabovejunctionwithhydrorhiza;taller
stem branched, lightly fascicled with several wide, tangled
tubes running almost to tip of colony and along primary
Figure 1. Map ofthe Antarctic showing BANZARE stations from branches. Branching irregular and disorderly, branches bent
whichHaleciumisrecorded,station 1785,CommonwealthBay,from outwardsatvariousanglesfrommainstem,ultimatebranches
theAAE1911 - 1914expedition. short, straight, monosiphonic. Monosiphonic branch
internodesfairlywide,cylindrical,wallssmooth,nodesdeep,
FamilyHaleciidaeHincks, 1868 oblique, sloping away from hydrophore, a tumescence and
often one or several deep corrugations in perisarc above
Thecate hydroids with shallow, saucer- or basin-shaped
node.
hydrothecae. Hydrotheca radially symmetrical, usually with Primaryhydrophoresalternateonstem,onedistaloneach
diaphragm;marginentire,withoutoperculum.Hydranthlarge internode,cylindrical,lengthvariablebuttypicallymoderately
and usually not completely retractable into hydrotheca, with long, abcauline wall curving smoothly away from internode,
conical hypostome and one circlet of filiform tentacles. adcaulinewallmoreorlessstraight.Hydrothecabowl-shaped,
Nematophorespresentorabsent. Gonophoresinformoffixed expandingfromdiaphragmtomargin,rimevertedandalittle
sporosacsorrarely,freedasmedusae. outrolled. Diaphragmfairlydistinct,afewdesmocytesabove.
)
HydroidsoftheBANZAREexpeditions, 1929-1931 167
undamaged, only two showing a flattened apex. As only the
spadixandsometissueremainsinmostgonothecae,sexcould
notbedetermined.
As dimensions ofthe present material fitreasonably well
with Vanhoffen’s (1910) and Totton’s (1930) descriptions of
Halecium antarcticum, the material is assigned to this
species.
Distribution.Haleciumantacticumisrecordedfromdepthsof
256minMcMurdoSound,290mintheRossSeaand385mat
Gauss Station.
Haleciumbanzaresp.nov.
Figure 2. A - C. Haleciumantarcticumfrom Station 107. A, fertile Figure3A-F
branch with well defined internodes and mature and developing
gonothecae. B, hydrophores and hydrothecae with desmocytes. C, HolotypeNMVF147450,Station41,threemicroslidesdisplaying
branchwithlinearregenerationofhydrophores. Scalebar:A,2mm; branch fragments; also preserved male colony. Paratypes NMV
B,0.3mm;C,0.5mm. F147451, Station 34, one microslide displaying one branch. NMV
F147452, Station 107, one microslide displaying small branch
mm
fragment;preservedfragmentedfemalestemorbranch70 long.
NMV
F147479, Station 107, onemicroslide displaying small branch
fragment. NMV F147455, Station 107, two microslides displaying
Hydrophorestypicallyregeneratedinlinearseriesofupto branch fragments; a small fragmented preserved colony. NMV
five; successive hydrophores variable in length, each arising F147479,onemicroslidedisplayingsmallbranchfragment.
from diaphragm of preceding hydrotheca; hydrophores with mm
Diagnosis. Colonies originally 80 - 140 high, the tallest
broadbasalkinksandupto 10closecorrugations.
stemarisingfromatuftedhydrorhizaofthin,tangled, shining
Gonothecae probably male, inserted in hydrophore on
stolons. Stem thick, brittle, branched, heavily fascicled;
distal monosiphonic branches; shape variable from flattened
polysiphonic tubes parallel, running almost to top of stem,
clavatetoovoidwithalowapicaldomewithflattenedtop. along primary branches and along some secondary branches.
Perisarc of stem, branches and hydrothecae rather thick,
Primary branches long, held out stiffly more or less in plane
verythinongonothecae.
almostperpendicularto stem, succeedingbranchesinthreeor
Colour (preservedmaterial deep honey brown, paler on fourorders;newbranchesgivenofffromahydrophoreorfrom
monosiphonicbranches; gonothecacolourless.
within a hydrotheca, typically long, monosiphonic, thin and
Measurements(pm) flaccidwithonetothreedeepbasalannulations.Monosiphonic
branchinternodes moderatelylong, cylindrical, walls smooth,
Branchinternode widening distally to hydrophore, nodes deeply indented,
length 419-514 obliquetotransverse,typically oneortwo constrictions above
andbelownode.
widthatnode 176-216 Hydrophores alternate, distal on internode and directed
Hydrophore outwards, projecting above level of node, walls cylindrical,
smooth, abcauline wall oftenfaintly bulging, adcauline wall
lengthtodiaphragm, adcaulinewall 196-274 slightly concave, often an internal thickening in perisarc
Hydrotheca abouttwothirdsdistanceupwall,joiningabcaulinewallwith
depth,margintodiaphragm 71-87 aexpfaanindtingdiaaglointatlle flrionem diinappherriasgamrct.o mHayrdgriont;herciam csihraclulloawr,,
diameteratmargin 277-316 weakly everted. Diaphragm distinct, transverse, a row of
desmocytes just above. Secondary hydrophores common,
diameteratdiaphragm 174- 237 arising from diaphragm of hydrotheca, a transverse
Gonotheca constriction in perisarc of secondary hydrophorejust above
length 1,176- 1,568 rimofhydrotheca.
Gonothecae of both sexes inverted conical, compressed,
maximumwidth 882-910 borne prolifically on younger branches, inserted without
distinct pedicel in wall of hydrophore or lower down on
Remarks. The taller stem is notable for its untidy habit of internode; male gonothecawithaminuteapical peak(visible
growthandthickeningofthepolysiphonictubesatoriginofthe onlyinsideview),femalesimilarinshapetomale,gonophore
primary branches. Several short monosiphonic branches are containinglargescatteredova;gonophoresofbothsexeswith
incipiently anastomosed, two showing reversal of growth so anapicalpadoftissue. Novisibleapertureineithersex.
thatthehydrophoresnowfacebackwardstowardsthestem. Perisarc of fascicled stem and branches firm, thinner on
The gonothecal perisarc is very fragile, few being monosiphonicbranches,verythinongonotheca.
168 JeanetteE.Watson
Figure3.A-F.Haleciumbanzaresp.nov.A,branchfromholotype.B,partofbranchfromholotype.C,D,hydrophoresfromparatype.E,male
gonothecafromholotype.F,(NMVF147452)femalegonotheca.Scalebar:A,50mm.B, 1mm.C,0.3mm.D-F,0,.5mm.
Colour oflower stem pale honey-brown, becoming paler Remarks. Although now much fragmented, the colonies were
distally,apexofstemandmonosiphonicbranchescolourless. probably tall and sparsely branched, arising from a thick,
mattedhydrorhiza.Internalthickeningoftheperisarcispresent
Measurements(pm)
in many hydrophores. The ova are scattered, not clustered
Branchinternode around the spadix ofthe gonophore. Both sexes appearto be
length 706-882 nearmaturity butas none ofthe gonothecae show any signof
anapertureitseemslikelythatreproductivematerialisreleased
widthatnode 113 - 176 byruptureoftheverythinperisarc.
Hydrophore The outwardly directed hydrophores and hydrothecae are
structurally similar to those of Halecium antarcticum
lengthofadcaulinewall ofprimaryto 150- 183 Vanhoffen (1910). However, according to Totton (1930),
diaphragm colonies ofthat species from McMurdo Sound were only 30
mm
Hydrotheca high, straggling, lightlyfascicled, andwith anastomoses,
depth, diaphragmtomargin 39-47 udinsltiiknecttihoen risobtuhsetmhuabciht osfhaHl.lowbearnzhayrder.otAhefcuartihnerH.imbpaonrztaarnet
diameteratrim 137- 164 whichisonlyhalfasdeepasthatofH. antarcticum.
widthatdiaphragm 125- 140 Etymology. The speciesname commemoratestheBANZARE
Gonotheca expedition.
length 1,027 Haleciumbrevithecumsp.nov.
maximumwidth 948
Figure4A-C
HydroidsoftheBANZAREexpeditions, 1929-1931 169
Holotype NMV F147457, Station 41, one microslide displaying Measurements(pm)
NMV
three branch fragments. Paratypes, F147458, Station 40, one
microslidedisplayingtwobranchfragments. NMVF147478, Station Monosiphonicbranchinternode
98, onemicroslide displaying onebranchfragment; somepreserved length 520 - 800
material.
widthatnode 200-240
Diagnosis.Infertilestemorbranchfragmentsofapresumably Hydrophore,length 220-240
larger colony. Stem (branch) fascicled, polysiphonic tubes
varyingfromknottedtoparallel.Branchingirregular,ultimate Hydrotheca
branches monosiphonic, given offfrom side ofahydrophore; diameteratmargin 220 - 240
branches beginning with three to five deeply indented
transversenodes,internodesthereaftermoderatelylong,walls depth, diaphragmtomargin 20-32
smooth, abaxial wall expanding smoothly into hydrophore;
Remarks. Unfortunately the material is meagre and infertile
nodes transverse to weakly oblique, deeply incised into
andthepermanentlymountedspecimenspoorlydisplayed.The
perisarc, a faint tumescence in internode above and below
species is remarkable for the shallowness of the hydrotheca
node. which provides minimal support for the hydranth. There is
Hydrophoresindistinct,adcaudalwalladnatetointernode, indicationofdesmocytes abovethediaphragmbuttheinterior
becoming free (although this scarcely visible) just below of most hydrothecae is obscured by tissue and adventitious
hydrotheca. Hydrotheca distal on internode, adcaudal wall material. There is an indication of incipient anastomosing of
adnate to internode; margin tilted at an obtuse angle away theultimatebranches.
from internode; hydrotheca very shallow, expanding Species withvery shallow adnatehydrothecae considered
imperceptibly to rim; rim not quite reaching node, walls of were: Halecium beanii (Johnston, 1838), Halecium sessile
hydrotheca thin; diaphragm transverse, strong. No marginal Norman, 1866,HaleciumralphaeWatsonandVervoort,2001
replications orlinearseriesofhydrophores. andHaleciumsp. 1 VervoortandWatson,2003.Thediameter
Gonothecaabsent. of the hydrotheca of Halecium brevithecum is, however,
greaterthaninthese species.
Etymology. The species is named for the remarkably short
hydrotheca.
HaleciumdelicatulumCoughtrey, 1876
Figure5A-B
HaleciumdelicatulumCoughtrey, 1876a: 299.-Coughtrey 1876b:
26, pi. 3, figs 4-5.- Stechow, 1913a: 144.- Stechow, 1913b: 9, 79.-
Stechow, 1923b: 5.-Bale, 1924: 235.-Ralph, 1958:334,figs lie,h-n,
12a-p.-Pennycuik,1959: 173.-Yamada,1959:31.-Leloup, 1960:218,
fig. 1.- Naumov and Stepanjants, 1962: 94, figs 16-17.- Rees and
Thursfield, 1965: 106.- Millard, 1966a: 464, fig. 10L.- Ralph, 1966:
158.- Blanco, 1968; 203, pi. 1, figs 14-18, pi. 2, figs 1-3.- Millard,
1968:253,256.-Dayetal,. 1970: 12.-Patriti,1970:23,fig.21.-Blanco
andBelluscideMiralles, 1972:7,figs3-5.-NaumovandStepanjants,
1972: 34,52.- Stepanjants, 1972: 72.-Vervoort, 1972a: 27, figs4-5.-
Vervoort, 1972b: 341, fig. 2a.- Morton and Miller, 1973: 152, fig.
54.10.-Watson, 1973: 166.-Leloup, 1974: 10.-Millard, 1975: 145,fig.
47F-L.- Watson, 1975: 159.- Gordon and Ballantine, 1977: 100.-
Millard, 1977a: 7, fig. 1C-D.- Stepanjants, 1979: 105, pi. 20, fig.
4A-V.- Watson, 1979: 234.- Hirohito, 1983: 5, 11.- Rho and Park,
1983:41,pi.2,figs 1-3.-Blanco, 1984c:262,figs 1-6.-Blanco1984d:
271,figs3-5.-ReesandVervoort,1987:25,fig.5.-StaplesandWatson,
1987: 218.-Ramil,BlancoandIglesiasDiaz, 1988: 72,fig. 2.-Giliet
al., 1989:78,fig.7B.-AltunaandGarciaCarrascosa,1990:54etseq.-
Genzano, 1990: 38, figs 2-5.- El Beshbeeshy, 1991: 32, figs4a,4b.-
Park, 1991:544.-Rocaetal., 1991:70.-GenzanoandZamponi, 1992:
40, fig. 17.- Park, 1992: 286.- Ramil and Vervoort, 1992a: 82, fig.
20a-c.- BranchandWilliams, 1993: 11.-Watson, 1994a: 66.-Altuna
Prados, 1995: 54.-Bouillonetal., 1995:45.-Hirohito, 1995: 20,text-
Figure4.A-C.Haleciumbrevithecumsp.nov.Holotype.A,branch. fig. 5a-c,pi. 1,fig. C.-Park, 1995: 10.- Genzano, 1996a: 290 etseq.-
B, branchinternodes. C, hydrophore and shallow hydrotheca. Scale Medel and Vervoort, 2000: 12 (cum yyn.).- Vervoort and Watson,
bar:A, 1mm,B,0.5mm.C,0.3mm. 2003:88,fig.16A-E.
170 JeanetteE.Watson
HaleciumflexileAllman, 1888: 11,pi.5,figs2,2a. Hydrophores arisingupto fivelinearinseries; variablein
HaleciumgracileBale, 1888: 759,pi. 14,figs 1-3 (notHalecium length,eacharisingfromdiaphragmofprecedinghydrotheca,
gracileVerrill, 1873:729). typicallybecomingshorteralongtheseries;proximalwallsof
HaleciumparvulumBale, 1888:760,pi. 14,figs4-5. youngerhydrophoresoftenweaklyundulated.
Material examined. NMV F147459, Station 97, one microslide Colonies dioecious; gonotheca inserted without distinct
displaying a branch fragment; some preserved material. NMV pedicel in intemode or hydrophore; immature gonothecae of
F147460 Station 98, one microslide displaying two branches. NMV bothsexesballoon-shaped,compressed,developinggonophores
F147461, Station 103, eleven microslides displaying branches from inall samplesimmature,surmountedbyanapicalpadoftissue.
mmiaclreoscloildoeny;dissopmlaeypirngesearvberdamnacthe.riaNl.MNVMFV14F71447776,2,tSwtoatimoincr1o0s7l,iodnees PHeyrdirsaanrtchwoifthcs.t2e4mstentmaocdleesr.ately thick, thinner on
displayingbranchfragments.
gonothecae.
mm
Description. Stems to 10 long, taller stems fascicled, Measurements(pm)
arising from tangled tubular hydrorhizal stolons. Younger
stems monosiphonic, flexuous. Basal cauline internodes with Internode
several deep proximal corrugations, internodes thereafter length 941 - 1,078
smoother, long, cylindrical, tending to become sympodial in
olderstems; nodes distinct, obliquetotransverse, onetothree widthatnode 74-111
shallow annulations in perisarc above and below node. Hydrophore
Hydrophores alternate, one distal on each primary cauline
internode sloping outwards from node, contiguous with length(abcauline) ofprimary 198-988
direction of internode; hydrophores variable in length, walls lengthofsucceedinghydrophores 78-387
cylindrical, smooth; branches when present, given off from
Hydrotheca
belowprimaryhydrophore.
Hydrothecae moderately deep, walls outwardly curved, depth,marginto diaphragm 43-82
margin circular, wide, rim strongly outrolled; margins not
replicated. Diaphragm distinct, transverse to shallow funnel- diameteratmargin 179-211
shaped,usuallyadistinctrowofdesmocytesabove. diameterofdiaphragm 94-129
Gonotheca
Length 537-672
Apical (maximum) width 435-577
Remarks.Thegonophoresinmostsamplesareimmature,those
ononlyonestemshowingdevelopingova.
Distribution. Circumglobalintropical, subtropical,andboreal
waters. Recorded at all depths to 2,250 m. It is sometimes
consideredconspecificwithHaleciumantarcticumVanhoffen,
1910,andwithH.mediterraneanWeismann, 1883,theformer
reportedfromisolatedAntarctic localities andthe latterfrom
many Mediterranean Sea localities (Vervoort and Watson
2003). Suchwidelatitudinal andbathymetricdistributionmay
indicate that several morphologically similar species are
possiblylumpedtogetherasH.delicatulum.
Haleciumelegantulumsp.nov.
Figure6A-C
HolotypeNMVF147463,Station103,twomicroslidesdisplaying
NMV
several infertile stems. Paratypes F147464, Station 103, two
NMV
microslides displaying stems. F147476, Station 103, one
microslidedisplayingasmallcolony.Allmaterialprobablyfromsame
colonyonsertulariidhydroid.
Diagnosis. Stems arising from a creeping hydrorhiza; stolons
Figure 5. A - B. Halecium delicatulum. A, fertile branch with tubular, smoothto crumpled. Hydrocaulus minute,variable in
developinggonothecae.B,hydrophoresinlinearseries.Scalebar:A, length, simple,unbranched,wallscylindrical,narrow, smooth,
2mm.B,0.3mm. without nodes but with occasional shallow constrictions
;
HydroidsoftheBANZAREexpeditions, 1929-1931 171
marking zones ofregrowth afterbreakage. Hydrocaulus with Remarks. As there are few clearly visible diaphragms and
eitherasingleterminalhydrothecaoralinearseriesofuptosix concave pseudo-diaphragms are visible in some hydrothecae.
hydrophores each arising from diaphragm of preceding In most instances the depth from rim to diaphragm has been
hydrotheca; base of hydophore swollen above supporting estimated as the distance from the base of secondary
diaphragm. hydrophorestotherimofthesupportinghydrotheca.
Hydrotheca moderately deep, trumpet-shaped, expanding The few remaining hydranths are too decomposed for
strongly from diaphragm to margin; rim circular, weakly descriptionbutseemtohavebeenverylongandextensile. No
outrolled; no replication of margin. Diaphragm delicate, desmocytes were seenbutthe interiorofmosthydrothecaeis
obscuredbyadventitiousmatter.
transversetoconcave,nodesmocytesvisible.
Two small, closely related species were considered:
Perisarcthickestinproximalstemregion,thinningdistally
Halecium tenellum Hincks, 1861 and Halecium fragile
verythinonhydrotheca.
Hodgson, 1950. Although most measurements of Halecium
Gonothecaabsent.
elegantulum fall within the range given by Cornelius (1995)
Measurements(pm) forH. tenellumfromtheNorthAtlanticandbyWatson(2003)
forH.tenellumfromthesubantarctic,bothofthesespeciesare
Hydrocaulus branchedwhereasallmaterialofH.elegantulumisunbranched
lengthoverall 1,764-4,840 showing no evidence of branching. Furthermore, the
hydrotheca ofH. elegantulum is elongated, not shallow as in
lengthofbasal segmenttonode 1,372 -4,840 H.fragile.
lengthofsucceedinghydrophores 95-593 Etymology. The name refers to the elegantly simple
diameterofhydrophore 43-70 hydrocaulus.
Hydrotheca
HaleciuminterpolatumRitchie, 1907
diameteratdiaphragm 59-78 Figure7A,B
depthrimtodiaphragm 20-28
HaleciuminterpolatumRitchie, 1907: 526,pi. 1, fig3,pi. 2,fig.
diameteratmargin 113-117 3.-Rees and Thursfield, 1965: 107, 197.- Smaldon et al, 1976: 17-
Stepanjants, 1979: 103, pi. 16, fig. 7.- Blanco, 1994a:156.- Blanco,
1994b: 186.
Material examined. NMV F147466, Station 88, two microslides
displayingsmallbranchfragments;apreservedmalecolony.
Description. Colonies branched, reaching aheight of30 mm.
Hydrorhiza a mass of corrugated tubular stolons. Stems
fascicled, lower stem region a loose aggregation of, stolons
becomingpolysiphonictubes,passingalonglowerbranchesto
mid-regionofcolony;stemsthereafterprofuselyandirregularly
branched.
Youngerbranchesmonosiphonic,typicallyasinglebranch
givenofffromageniculationofhydrophorebelowahydrotheca,
sometimes a second branch given off on opposite side of
hydrophore;branchesrugosetodeeplycorrugatedandjointed
but lacking true nodes; joints transverse to weakly oblique.
Hydrophores variable in length, often corrugated, typically a
shortmoreorless smoothsegmentbelowhydrotheca.
Hydrotheca deep bowl-shaped, expanding strongly from
diaphragmtomargin;margincircular,rimstronglyoutrolled.
Diaphragm distinct, some secondary and succeeding
hydrophores arising in a linear series from diaphragm of
preceding hydrotheca; hydrophores fairly short, typically
deeplycorrugated.
Hydranthswithc. 20-24ratherstubbytentacles,notwell
preserved.
Male gonotheca ovoid to balloon-shaped, flattened,
inserted on a very short narrow pedicel in an axil or in a
Figure 6. A - C. Halecium elegantulum sp. nov. NMV F147463, hydrotheca, a minute apical protuberance visible in some
holotype. A, whole stem. B, hydrophore. C, replicated hydrothecae. gonothecae. Gonophores near maturity, almost filling cavity
Scalebar:A,0.5mm.B,C,0.1mm. ofgonotheca.
172 JeanetteE.Watson
Perisarc of stems and branches very thick, thinner on Inmanyrespectsthepresentmaterialfallswithintherangeof
hydrothecaandgonotheca. dimensions of H. ovatum Totton, 1930 and measurements
Colour (preserved material), pale honey brown, youngest deducedfromRitchie’sdescription.Althoughthehydrocauliof
branchesyellowish, gonophoresdarkerbrown. thetwospeciesaresuperficiallyalike,theovoidtoquadrangular
Measurements(pm) gonotheca of H. ovatum is considerably smaller than the
lenticulargonothecaofH. interpolatum. Itherefore assignthe
Branch presentmaterialtoH. interpolatum.
distancebetweenhydrothecaeon 745- 1470 Distribution. South Orkneys. This is the first record of the
branch speciesfromAntarctica.
widthofsmoothsectionofbranch 134-158
HaleciumovatumTotton, 1930
Hydrotheca
Figure8A,B
diameteratdiaphragm 134- 150
diameteratmargin 269-300 fig. 1H.a-lSetecpiaunmjaontvsa,tu19m79T:ot1t0o3n,,p1i.93200:fi1g4.3,laf-igg..-3P.-enVaerCvaonotretr,o,1917929:1:33498,,
depth,margintodiaphragm 95- 134 pi. 2, figs g-h.- Blanco, 1994: 160: 156.- Blanco, 1994: 187.- Pena
Cantero and GarciaCarrascosa, 1996: 12, fig. 2G-H.- PenaCantero
Gonotheca andGarciaCarrasocosa,1999:63:212etseq.-Watson,2003: 166,fig.
length,includingpedicel 869-909 15D,E.-VervoortandWatson,2003: 86.
maximumwidth 474-553 Notes and supplementary description from holotype. To
establish the identity of Halecium interpolatum it became
Remarks. Ritchie’s material ofH. interpolatum was infertile, necessary to examine type material of Halecium ovatum.
his descriptionwas general andlackedimportantdimensions. Although Totton provided an adequate description and
dimensionsofHaleciumovatumhisfigureswerepoor,andthe
gonotheca was not figured. I have compared the BANZARE
materialwiththeholotype(alcohol-preservedcolony)andfour
paratype microslide preparations ofHalecium ovatum loaned
bytheNaturalHistoryMuseum,London.Abriefsupplementary
description of the important diagnostic characters from the
holotype(glycerol-mounted)ofHaleciumovatumis given.
The holotype colony (BMNH No.29.10.10.1) comprises a
densetuftoflongandshortstemsgrowingonanotherhydroid.
Hydrocauliarisefromatangledadherentmeshworkoftubular
stolonsentwinedwithhydrorhizaeoftheotherhydroid.
Shorterstemsmonosiphonic,tallerstemsfascicledwithup
to 10 polysiphonictubes; stems arborescently branchedin all
directions up to two thirds oftheirlength, ultimate branches
monosiphonic.
Maturefemale gonothecae small,borne abundantly onall
but distalmost branches, inserted on a short pedicel in a
hydrotheca typically situated in a fork between two or three
branches but hydrotheca often overgrown by polysiphonic
tubes; body of gonotheca ovoid to subquadrangular with a
verythin, smoothperisarc; apertureterminal, small, circular,
surroundedby averylowfragile collar; immature gonotheca
kidney-shapedasdescribedbyTotton.
Nematocysts in tentacles undischarged ?anisorhizas
capsuleoval, 11-12x6-7 pm.
Measurements(pm)ofgonothecaofHaleciumovatum
Lengthofpedicel ofgonotheca 80
Lengthofgonotheca 784-1176
Figure 7. A, B. Halecium interpolatum. A, fertile monosiphonic Widthofgonotheca 588-901
Ab,ra0n.c3hmwmi.thBn,ea0r.l5ymmma.turemalegonotheca.B,hydrotheca.Scalebar: Diameteroforifice 80
HydroidsoftheBANZAREexpeditions, 1929-1931 173
diaphragm)ofperisarcpassingdiagonallythroughhydrophore
from near junction of diaphragm with abcauline wall to
adcaulinewall.
Hydranthslargewithc. 24tentacles,poorlypreserved.
Secondary hydrophores rare but when present, arising
fromdiaphragmofhydrotheca;hydrophoretypicallybecoming
anewbranchbeginningwithtwotofourdeepirregulartwists,
increasinginnumberwithageto 10deepcorrugations.
Gonothecaeabundantonmonosiphonicbranches,inserted
without distinct pedicel on hydrophore or in hydrotheca;
gonotheca sub-ovoid to almost triangular, strongly
compressed, apex with minute twin peaks and no apparent
aperture; gonophore oval,withclearly definedcentral spadix
and apical pad of tissue armed with an array of large
nematocysts.
Nematocysts of two morphological categories, none
discharged:
- large bean-shaped isorhizas, 19-24 x 7-9 pm, abundant in
apical pad of gonophore and throughout coenosarc of
branches.
- leaf-shaped nematocysts (category indeterminate) in
tentacles,8x2 pm.
Perisarcofhydrocladia,hydrothecae andgonothecaevery
Figure8.A,B.Haleciumovatum,holotypecolony,BMNHReg.No. thin;thickerandrobustinolderpartsofcolony.
29.10.10.1.A,partofstem.B,emptyfemaleovoidandsubquadrangular Colour of thickest branches (preserved material) dark
gonothecae.Scalebar:A, 10mm.B, 1mm. brownfadingtohoneybrowninyoungerparts,monosiphonic
branches pale creamy white to transparent, gonophores
brown.
Measurements(pm)
Haleciummacrocaulussp.nov.
Monosiphonicbranch
Figure9A-F
NMV lengthofapophysis, abcauline side 237-395
Holotype F147467,Station107,onemicroslidedisplayinga
branch; also alarge preservedfragmented colony. Paratypes NMV lengthofproximal (corrugated) 882- 1,568
F147468,Station107,onemicroslidedisplayingtwobranchfragments. internode
NMV F147469, Station 107, two microslides displaying branch
fragments. lengthofsucceeding (hydrophorate) 703-798
mm internodes
Diagnosis.Thickestfragments(stemormajorbranches)6
wide at base and 200 mm long; branching profuse and widthatnode 182-237
irregular, originally all around stem. Stem and branches Hydrotheca
heavily fascicled by numerous thin, almost parallel tubes;
tubesbecomingfeweronyoungerbranches,ultimatebranches diameteratdiaphragm 198-221
(hydrocladia) monosiphonic; several monosiphonic branches depth,marginto diaphragm 59-66
also given off from lower fascicled stem region. Branching
sub-dichotomous,forksarisingfromwithinahydrotheca;base diameteratmargin 215-254
of branch typically heavily corrugated, walls becoming Gonotheca
smoothdistally. lengthoverall 882- 1,431
Ultimatebranchesstraight,flaccid,internodesfairlyshort,
walls smooth, nodes oblique, tilted away from hydrotheca, maximumwidth 588- 1,078
wall of internode expanding distally to accommodate
hydrophore; hydrophore short, cylindrical, very close butnot Remarks. It is uncertain whether the material originally
adnatetointernode. consisted of a large colony, now broken, or several smaller
Hydrotheca shallow, adcauline wall closely adpressed to colonies. Despite the apparent robustness of the colony the
internode; walls expanding only slightly from diaphragm to hydrocladialperisarcisverythin,possiblyhavingdeteriorated
margin; rim circular, tilted at 50 - 55° to axis of internode, duringpreservation.
very weakly everted. Diaphragm distinct, a row of minute Theadcaulinewallofthehydrothecaissocloselyadpressed
thorn-shaped desmocytes closely above; a septum (false to the internode that the gap is only obvious on close
174 JeanetteE.Watson
Figure9.A-F.Haleciummacrocaulussp.nov.fromholotypeandparatype.A.fertilebranch.B,monosiphonicpartofbranchwithgonotheca.
C,D,branchinternodes.E,hydrothecawithfalsediaphgarmanddesmocytes.F,viewofgonothecashowingapicalprotuberances.Scalebar:A,
15mm.B,2mm.C,D,0.5mm.E,F.0.3mm.
examination. A diagonal septum (false diaphragm) belowthe Etymology.Thespeciesisnamedforthelargesizeofthecolony.
transversediaphragmoccursinmanyhydrothecae;itisusually
obscured by tissue and visible only in cleared mounts. The Haleciumtubatumsp.nov.
cdleossmeoctyottehseadreiaaplhsroadgimf.ficNuolttroepsleiec,atbieoinngofvehryydrsomtahlelcaaendwsaest Figure 10A,B
NMV
found. Holotype, F147470, Station 105, three microslides
The numerous gonothecae are quite small compared with displayingseveralstems.ParatypesNMVF147471,Station 105,four
NMV
tghoenotshiezeca,ofsutghgeestcionlgonnieeasr.-maTthueritgyo.nAosphtohrereeiaslnmoosetvifdiellnscethoef mdiiscprloasyliindgescodliosnpyl.ayiNNnMgMVVcolFony1.47477, StaFt1i4o7n47928,, oonnee mmiiccrroosslliiddee
anaperture,thecontentsareprobablyreleasedbyruptureofthe displaying colony. NMV F147480, Station 90, one microslide
verythinperisarc. Thenematocysts are abundantinthe apical displaying colony. F147481, Station 107, one microslide
displayingcolony.
pad above the gonophore and inthe coenosarc ofthe colony;
theyareverylargeandvisibleevenatlowmagnification. Diagnosis. Hydrorhiza reptant on hydroid host, stolons thin,
Large arborescent species of Halecium with closely tubular, rugose to smooth. Hydrocauli fragile, variable in
adpressed hydrophores considered were: Halecium beanii length, to 4 mm, unbranched; hydrocaulus above hydrorhiza
(Johnston, 1838), Halecium halecinum (Linnaeus, 1758), weaklyrugoseorwithuptofourdeepannulations;hydrocaulus
Halecium sessile Norman, 1867 and Haleciumjaederholmi (pedicel) thereafter cylindrical, straight or weakly curved,
Vervoort, 1972. H. beanii was rejected because the colonies walls smooth.
andhydrothecaldimensionsaresmallerthanthoseofHalecium Pedicel bearing a single terminal hydrotheca; hydrotheca
macrocaulus H. halecinum and H. sessile were discounted wide,bowl-shaped,wallsflaringmarkedlyfromdiaphragmto
;
because of differences in colony morphology. Vervoort’s rim; rim circular, smooth, strongly outrolled, a row of
(1972) description of H. jaederholmi is of a much smaller desmocytesabouthalfwaybetweendiaphragmandrim.Afew
specieswithcompletelyadnateanddeeperhydrothecae. secondary and succeeding hydrophores in linear row from