Corymorpha rubicincta, a new Hydroid (Hydrozoa, Anthoathecata, Corymorphidae) from Port Phillip, Australia

2008·2.1 MB·

by  Jeanette E Watson

MemoirsofMuseumVictoria65: 185-188(2008)
ISSN 1447-2546(Print) 1447-2554(On-line)
http://www.museum.vic.gov.au/memoirs/index.asp
Corymorpha rubicincta a new Hydroid (Hydrozoa, Anthoathecata,
,
Corymorphidae) from Port Phillip, Australia
JeanetteE. Watson
Honorary ResearchAssociate, Marine Biology Section, Museum Victoria, RO. Box 666 Melbourne, Victoria, 3001,
Australia,[email protected]
Abstract Watson,J.E.2008.Corymorpharubicincta,anewHydroid(Hydrozoa,Anthoathecata,Corymorphidae)fromPortPhillip,
Australia.MemoirsofMuseumVictoria65: 185-188.
Corymorpha rubicincta sp. nov. a solitary hydroid is known only from shallow water silty seabed atthe type
locality in Port Phillip, Victoria,Australia. It is fertile in winter, gonophores are probably cryptomedusoid. The red
hydrocaulinebandisdiagnostic.
Keywords Corymorpharubicincta.PortPhillip,Australia,shallowwatersiltyseabed,redhydrocaulineband,cryptomedusoid.
Introduction collected from 4.5 -6 m depth. Material initially hardened in 5%
formalinthentransferredtoalcohol.
DuringanecologicalsurveyinJune,2002, 1 kmnorth-westof
Point Richards in Port Phillip, Victoria, Australia, solitary Description (from live andpreserved) holotype andparatypes
hydroidswerefoundinanabandoneddredgeexcavation4-6m Hydroidssolitary,hydrocaulusupto4cmhigh,baseofhydrocaulus
deep. The habitat in the excavation is silty sand heavily blunt,embeddedinsedimentandrootedbyathickmass ofsoft,
bioturbated by infaunal polychaetes and bivalve molluscs. In intergrownhair-like filaments adherentto sand grains; filaments
June,2008morespecimenswerecollectedfromtheexcavation slightlythickernearpointofattachmenttohydrocaulus.
and insituunderwaterphotographstaken. Watertemperature Hydrocauluscylindrical,widestatbase,taperinggradually
attimeofcollectionwas 13°C. to a transverse red band about one third to half distance up
Holotype and paratype material is lodged in Museum stem;stemthenofsamediametertobaseofhydranth.Perisarc
Victoria(NMVF). above band thin and becoming almost colourless distally; a
constriction at base ofhydranth; in some stems a second red
FamilyCorymorphidaeAllman, 1872 band atconstriction markingjunction ofstemwith hydranth.
Cauline perisarc below primary band thick and gelatinous
CorymorphaM.Sars, 1835 withnumerousdigitatependulouspapillae;papillaebecoming
shorter with distance up stem, gradually reducing to wavy
Diagnosis (afterBrinckman-Voss (1970), Petersen (1990) and discontinuous internal lines of cream-coloured spots
Bouillonetal(2006). sometimesinterspersedwithredblotches.
Hydroid solitary, hydranth vasiform with one or several Hydranth long, vasiform, capable of great extension and
closelysetwhorlsoforalfiliformtentaclesandaboralwhorlof contractionwithasinglewhorl of20-24long, slenderfiliform
filiform tentacles; hydrocaulus with thin perisarc, with aboral tentacles tapering to a pointed tip; approximately 30
longitudinalperipheralcanals;lowerpartwithpapillaeand/or oraltentacles,muchshorterthanaborals,arrangedinatuftof
long anchoring filaments; parenchymatic diaphragm; two closely set rows, tentacles in each row alternating with
gonophores borne on blastostylesjust above aboral tentacles those above and below. Hypostome conical when closed and
givingrisetofreemedusaorfixedsporosacs. oral tentaclestightly bunched, when hypostome widely open,
Material examined. Holotype NMVF147476, one stem alcohol tentaclesarchedbackwards.
preserved,coll:J.E.Watson,5June2008.Paratypes,NMVF 147477, Gonophoresfixedsporosacs,borneonblastostylessetinone
six stems alcohol preserved, coll: J.E. Watson, 18 June 2002. whorljustabove aboraltentacles, ablastostyleusuallybetween
NMVF147478,sixstemscoll:J.E.Watson,5June2008.Allmaterial eachsecondorthirdtentacle.Blastostyleshort,stout,unbranched,
186 JeanetteE.Watson
straighttobackwardlyrecurved; upto 20 small subsphericalto
knuckle-shaped gonophores clusteredin groups ofthreeto five
without peduncle along one side; gonophores probably
cryptomedusoidwithathickepidermallayerheavilyarmedwith
nematocysts;morematuresporosacspackedwithsmallova.
Colour:rootingfilamentscolourlesstogreenish;lowertwo
thirds of hydrocaulus yellow to reddish, colour gradually
fading distally to primary band; primary band brick red;
papillaebelowbandcream.Bodyofhydranthpaleflesh-colour,
hypostome white to cream, usually a band of red spots just
aboveaboraltentaclesandsimilarspotsonbasesofinnerrow
of oral tentacles; blastostyle and gonophores colourless to
white.Tentaclestranslucentwhite.
Measurements(mm) ofhydrocaulusfromlivespecimens
Hydrocaulus
lengthoverall 20-40
2-3
diameteratbase
diameteratcaulineband 2.2-2.5
diameterbelowhydranth 1.5-2
distancefromredcaulinebandtobaseof 5-12
Figure2.Rootingfilaments,drawnfromparatype.Scalebar5mm.
hydranth
Hydranth
diameteratconstrictionbelowaboraltentacles 1.5-2
lengthoforaltentacle 3.8-45
Nematocysts,measurements(pm)
lengthofaboraltentacle 12-14
Nematocyst Dimensions Aboral Oral Gonophore
Blastostyle(immature)
Tentacle Tentacle
length 0.1 -1.5 Stenotele(i) Absent N A
Cnidome comprising one category (stenotele) of five size capsule 18-19x13-15
classes and three categories ofnematocysts each of one size shaft 13
class (desmoneme, microbasic mastigophore, heterotrichous Stenotele(ii) Absent Absent A
anisorhiza).
capsule 15-17x 14-15
shaft 14
Stenotele(iii) C Absent Absent
capsule 14-16x11-14
shaft 12
Stenotele(iv) A Absent R
capsule 12-13x8-10
shaft 8-10
Stenotele(v) Absent C Absent
capsule 10-11x8-9
shaft 8
Desmonene 7-10x6-8 A A Absent
Microbasic 12-15x4-6 A A C
mastigophore
Heterotrichous R Absent R
anisorhiza
diameter 15-16
Key to abundance: A = abundant, C - common, N - not
Figure 1. Corymorpha rubicincta, fertile hydranth, in situ image, common,R=rare
depth5m.
)
CorymorphaRubicincta,anewHydroid(Hydrozoa,Anthoathecata,Corymorphidae)fromPortPhillip,Australia 187
Aboral, oral tentacles and gonophores with abundant appearto be groups ofzooxanthellae. Papillae arepresenton
stenoteles. Desmonemes absent from gonophores. The the lowerpartofmost stems butare absentfrom some stems
heterotrichous anishorhiza has a very long and spinous and may develop as the hydrocaulus matures; well developed
thread. papillae arelong andfinger-like,becomingbutton-likeupthe
stem, then gradually fading to blotches in the perisarc. The
Remarks distinctive red band part way up the stem is present in all
hydrocauli;onlysomestemshavethesecondary,thinnerband
SimilarspeciesofCorymorphaconsideredwere:Corymorpha
belowthehydranth.
nutansM. Sars, 1835, CorymorphajanuariiSteenstrup, 1854
BlastostyleswereabundantonspecimenscollectedinJune
and Corymorpha forbesii (Mayer, 1894); all were rejected (winter) of 2002 and 2008 but were absent from the few
because they have many more aboral tentacles than
hydrocauli remaining at the locality six weeks later in July,
Corymorpha rubicincta and moreover, all release medusae. 2008. The thick epidermal layer ofthe gonophores obscures
Other Pacific records of Corymorpha are Corymorpha
the internal structures thus preventing accurate diagnosis
symmetrica Hargitt, 1924and Corymorpha tomoensisIkeda,
1910, and Corymorpha sagamina Hirohito, 1988 both of
whicharealsolikelytoproducemedusae.Corymorphacarnea
(Clark, 1876) is about three times larger, has branched
blastostylesandmedusoidgonophores(seeHirohito, 1988).
TheonlypreviousrecordofCorymorphafromAustraliais
thatofStechow(1932)whodescribedCorymorpha(Euphysa
balssi from Shark Bay in Western Australia. His infertile
colony was fromthe carapace ofthe spidercrab Schizophrys
dama,thetypematerialofwhichislodgedintheZoologische
Staatssammlung, Munchen (Ruthensteiner et al. 2008). The
carapace ofacrab (seephotograph, Figure 2E, Ruthensteiner
etal.,2008) seemsanunlikelyhabitatforCorymorphawhich
is usuallyfound onasilty seabed. Ruthensteineretal. (2008)
also give a figure (Figure 7B) of a previously unpublished
illustrationofaspecimenofCorymorphadrawnbyStechow’s
graphicistW.RosslerwhichmaybeStechow’sspecimenofC.
balsii. Examination of the colony on the crab carapace will
settle the question of whether it is indeed a Corymorpha or
more likely, a species of Zyzzyzus. Although I have not
examinedthismaterialandwhilethetrueidentityofStechow’s
material needs to be established, the species is clearly not
Corymorpharubicincta.
The lines passing upwards through the hydrocaulus of
Corymorpharubicinctaareobscuredinthelowerstemregion
bythethickgelatinousperisarc. Underhighmagnificationthe
reddish specks and blotches throughout the hydrocaulus
Figure4.Cnidome,4A,stenotele(i)fromoraltentacles.4B,stenotele
(ii)fromgonophores.4C,stenotele(iii)aboraltentacles.4D,stenotele
(iv)fromaboraltentaclesandgonophores.4E,stenotele(v)fromoral
tentacles.4F,desmonenefromoralandaboraltentacles,4G,microbasic
Figure3Blastostyle,twoviewsshowingdevelopinggonophores.Scale mastigophore. 4H, heterotrichous anisorhiza from aboral tentacles
bar, 1mm. andgonophore.Scalebar,20pm.
188 JeanetteE.Watson
however, they are almost certainly cryptomedusoid. The ova Da Silveira F. and Migotto A. 1992. Rediscovery of Corymorpha
are small, 10-32pmin diameter, although not numerous and januarii Steenstrup, 1864 (Hydrozoa, Corymorphidae) on the
arevisibleonlyunderhighmagnificationwhenthegonophore southeasterncoastsofBrazil.Steenstrupia 18(4):81-89.
iscrushed.Aninsituimage(June2008)showedagroupof35 Sars, M. 1835. Beskrivelser ogjagttagelser over nogle maerkelige
young hydrocauli (some to 6 mm high) grouped around the eller nye i havet ved den Bergenske kyst levende dyr af
baseofaparentstem, suggestingthatfertilizedovamay drop polypernes,acelphermes, radiaternes, annelidermes og
from the gonophore directly to the substrate to commence molluskernes classer, med en kort oversigt over di hidtil af
growthasnewhydrocauli. forfatteren sammestedsfundne arter og deresforekommen. T.
InformationonthecnidomeofthehydroidofCorymorphais Hallager,Bergen,xii,81 p.
from Bouillon (1985), Schuchert (1996) and da Silveira and Bouillon J. 1985a. Essai de classification des Hydropolypes-
Migotto (1992) who list desmonemes, anisorhizas, stenoteles Hydromeduses (Hydrozoa-Cnidaria). Indo-Malayan Zoology 2:
and micro- and macrobasic mastigophores and heterotrichous 29-243.
anisorhizas. With the exception of macrobasic mastigophores BouillonJ., Gravili,C.,Pages,F., GiliJ-M. andF. Boero. 2006. An
Corymorpharubicinctahasthesamecategoriesofnematocysts. Introduction to Hydrozoa Memoires du Museum national
This is the first undoubted record of Corymorpha from d’Histoirenaturelle194:1-591.
Brinckman-Voss A. 1970. Anthomedusae/Athecata (Hydrozoa,
Australia.
Cnidaria)oftheMediterranean. Part 1. Capitata-FaunaeFlora
Ecology. Corymorpha rubicincta occurs on silty substrate in GolfidiNapoli39:1-96,pis 1-11.
quietwaterconditionswithinanarrowdepthrangeof5-6mon Hirohito, Emperor of Japan 1988. The hydroids of Sagami Bay
theslopingsidesofanoldexcavationintheseabed.Therather collected by His Majesty the Emperor of Japan. Biological
flaccid scatteredhydrocauli standmore orless erectabovethe LaboratoryoftheImperialHousehold,Tokyo,pp. 1-179,pis 1-4.
bed.Itmaybeasummerspeciesasintensivesearchatthetype PetersenW. 1990. Evolution andtaxonomy in capitatehydroids and
locality in July (mid-winter) at a water temperature of 10°C medusa. Zoological Journal of the Linnaean Society 100(2):
foundonlytwomoribundstems. 101-231.
Ruthensteiner B., Reinicke, G-B. and Straube, N. 2008. The type
Etymology. The species is named forthe red band encircling material of Hydrozoa described by Eberhard Stechow in the
thehydrocaulus. ZoologischeStaatssammlung,Munchen.Spixiana31(1):3-27.
Schuchert P. 1996. The Marine Fauna of New Zealand: athecate
Acknowledgements hydroids andtheirmedusae (Cnidaria: Hydrozoa). NewZealand
I thank Andrew Newton for underwater photography of the OceanographicInstitute(NIWA)Memoir106: 1-159.
hydroids and Dr Wim Vervoort of the National Museum of Schuchert P. 2001. Hydroids of Greenland and Iceland (Cnidaria,
Natural History, Leiden, The Netherlands, forhelpful advice Hydrozoa).MeddelelseromGr0nland.Bioscience53: 1-184.
and Dr Peter Schuchert of Museum d’Histoire Naturelle, Stechow E. 1932. Neue Hydroiden aus dem Mittelmeer und einige
Pazifischen Ozean, nebst Bermerkungen liber einige wenig
Geneve, Switzerlandforcriticismofthemanuscript.
bekannteFormen.ZoologischerAnzeiger100: 81-92.
Steenstrup J. J. S. 1854. En my og tropisk Art af Smaagoplernes
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