Intertidal and shallow water hydroids from Fiji. 2. Plumulariidae and Aglaopheniidae

36 Pages·1991·9.5 MB·English

by  J S Ryland

INTERTIDALAND SHALLOW WATER HYDROIDS FROM
FIJI. 11.
PLUMULARIIDAE AND AGLAOPHENIIDAE
J.S. RYLAND AND M.J. GIBBONS
Ryland, J.S. and Gibbons, M.J. 1991 08 01: Intertidal and shallow water hydroids from
Fiji. 11. Plumulariidae and Aglaopheniidae. Memoirs ofthe Queensland Museum 30(3):
525-560. Brisbane. ISSN0079-8835.
Nineteen species of Hydroida Plumulariidae and Aglaopheniidae were obtained from
intertidal reefs and shallow waters in Fiji. The generic name Monotheca Nutting is used
for species of Plumularia (s. lat.) having a single hydrotheca per hydrocladium, for
example, M. obliqua (Saunders in Johnston); and Lytocarpia Kirchenpauer and Macro-
rhynchia Kirchenpauerare preferred to theirbetter knownjuniorsynonyms,respectively
Thecocarpus Nutting and LytocarpusAllman.Lytocarpia bathyalis sp.nov., L. nicpenni
sp.nov. and L. vitiensissp.nov. are erected. All species are illustrated with line drawings
madeusingacameralucida,andsubstantialvariabilityisfiguredforGymnangiumeximium
(Allman) andLytocarpiaphyteuma (Kirchenpauer). IfJHydroida, taxonomy. Pacific, Fiji,
coralreefs, intertidal, shallowwater.
J.S.RylandandM.J.Gibbons,DepartmentofZoology(nowSchoolofBiologicalSciences),
University College of Swansea, Singleton Park, Swansea, SA2 8PP, Wales, U.K.;
M.J.G. present address, Department ofZoology, UniversityofCape Town, Rondebosch
7700, RepublicofSouthAfrica; 20August, 1990.
Thispaperconstitutesthesecondandfinalpart nematolhecae; terminatedby ahingejoint. Stem
ofour account ofhydroids collected by the first thecate distally, with alternate thecate and athe-
authorin Fiji during 1978-80,anddealswiththe cate internodes separated by almost transverse
Plumulariidae (in the broad sense). All the non- and very oblique nodes respectively. Athecate
plumulariidhydroidsweredescribedbyGibbons internodesofvariablelength,usuallylongerthan
and Ryland (1989) whose account should be thecate internodes; one or two nematothecae;
consulted for a general introduction and for without internodal septa. Thecate internodes
details ofthe stations. with four nematothecae: one medio-inferior, not
reaching base of hydrotheca, a pair of laterals
SYSTEMATICS
which rarely overlap the thecal margin, and one
small medio-superiornematothecainaxilimme-
Family PLUMULARIIDAE diatelybehindfreeadcaulinewallofhydrotheca;
internodal septa absent.
Antennella Allman, 1877 Hydrothecae cup-shaped, adnate for one-half
to two-thirdsvertical height, with sides more or
A. secundaria (Gmelin, 1791) less straight and parallel, flaring to margin; or
(Fig. 1) abcauline wall convex in lower region before
expanding to margin above; variably thickened.
SertulariasecundariaGmelin, 1791: 3854 Margin smooth and oblique, at 45-55*’ to axis.
Antennellasecundaria{GmeVin, 1791):Millard,1975: Basal hydrothecae broader and more squat than
332; Vervoort and Vasseur, 1977: 64 those distally.
Medio-inferior nematotheca two-chambered
Description butofvariable length and mobility; distalcham-
Colony typically comprising erect, un- ber scoop-like, adcauline wall much lower than
branched stems without hydrocladia (but see abcauline. Lateral nematothecae pedicellate,
Variations),reaching 10 mm. Stemconsistingof arising near top ofadnate region of hydrolheca;
basal athecate and distal hydrotheca-bearing infundibulariform, the distal chamberbroadand
regions. The formerofvariable length, with one shallow, with rim sloping gently mesiad from
or more transverse nodes proximally; only its outeredge. Medio-superiornematothecaofvari-
distalmost internode bearing mesial able size; minute and one-chambered or larger
526 MEMOIRS OFTHE QUEENSLAND MUSEUM
FIG. \.Antennellasecundaria. A, partofcolony. B, hydrothecae and nematothecae. C, female gonotheca. D,
male gonotheca. A,C,D, QMGL1029L Joske’s Reef. B, QMGL10292,GreatAstrolabe Reef.
and two-chambered, distal chamberwith almost on the posterioror postero-lateral surface ofthe
non-existent adcauline wall. basal internode. While A. secundaria and M.
Colony hermaphrodite. Gonothecaeborne im- quadridensare very similar, Millard (1975) has
mediately below hydrothccae, often male and pointedouttheycanbedifferentiatedbyexamin-
female from below same hydrotheca. Both with ingthe main colony axis. Ifthis isformedby the
pedicel of two segments, curved and pear- firsthydrocladiumthenthespecimenisA.secun-
shaped, taperingproximadand roundeddistally, daria: if it is formed by the bases ofsuccessive
with operculate aperture; bearing 2-3 two- hydrocladia then M. quadridens. Vervoort and
chambered nematothecae basally. Male Vasseur (1977) have given very good descrip-
gonotheca smaller and less truncated distally. tions ofthe two forms.
VariationsandRemarks Measurements (|xm)
Unbranchedcoloniesarecommoneverywhere Measurements for unbranched and branched
around Fiji. However, branched forms, which coloniesrespectively.Hydrocladium;thecatein-
tend to resemble Monastaechas quadridens ternode 105-240, 130-170; athecate internode
(McCrady, 1857) in colony structure and 300-420, 280-410. Hydrotheca: abcauiine
helicoid sympodial branching, are also present. length 160-190, 140-180; adnate adcauline
In these, an apophysisispresenton theposterior length 105-145, 135-140; free adcauline length
surfaceofthe basal athecate internode, immedi- 70-115, 110-125; marginal diameter 165-225,
atelybelowtheterminal hinge-joint.Thisin turn 160-200. Gonotheca (seen only on unbranched
gives rise to another athecate internode ofvari- colonies; presumed S and 9 respectively): ver-
able length, with a variable number of tical height 324-432, 396-450; opercular
nematothecae,terminalhinge-jointandposterior diameter 72-90, 144-162; maximum width
apophysis, etc. Each branch, therefore, arises 191-210, 252-238.
fromanapophysisontheposteriorsurfaceofthe
previousone. Colonieswithmorethanfoursuch OccurrenceinFiji
branches rare; occasional colonies have two Common andwidespread, usually undercoral
hydrocladial apophysesarisingat thesame level boulders, once on Thyroscyphus fruticosus;
HYDROIDS FROM
FIJI II 527
FIG.2.Halopterisbuskii. A,partofcolony. B,partofhydrocladium.C,gonotheca.OMGL10293,SuvaBarrier
Reef.
sometimessupportingHebellaparasitica (Suva Description
barrier reef). Ndeumba, 20 Aug 78 (BM Colony with erect stemsarisingfrom a hydro-
1984.5.17.38); with gonothecae 24 Jun 78 and rhiza, reaching 9 mm; consisting of basal athe-
18 Sep 78 (QM GLI0291; BM 1984.5.17.39). cate and distal thecate, hydrocladia-bearing
Alsocollected atTanaea,Tarawaatoll, Kiribati, parts, the two separated by a hinge-joint.
11 Feb 79. Proximal part may be subdivided by transverse
nodes; uppermost internode bearing anterior
WorldDistribution nematothecae in two longitudinal series. Distal
Cosmopolitan. Type locality; Mediterranean. part divided by oblique hinge-like nodes into
thecate internodes, each with one hydrotheca
Halopteris Allman, 1877 and up to six nematothecae: one medio-inferior,
one or two pairs lateral, and up to three medio-
Halopteris buskii (Bale, 1884) superior, in two longitudinal scries (either alter-
(Fig. 2) nate oropposite each other). One ortwo pairs of
subopposite hydrocladia arising on short
Plumulariabuskii 1884: 125 apophyses from sidesoffirst one or two cauline
Plumulariabuskii: Billard, 1913: 21 hydrothccae; thereafter, arrangement alternate,
Heterothecabuskii(Ba\e): Hirohilo, 1974: 30 one hydrocladium per internode. An athecate
Halopterisbuskii(Bale, 1884):VervoortandVasseur, internode may occur immediately above a
1977: 72 hydrotheca, in which case bearing one or more
528 MEMOIRS OFTHE QUEENSLAND MUSEUM
of the superior nematolhecae from internode Variations
below. A second pairoflateral nematolhecae may be
Hydrocladia, bearing hydrothecae on upper present per cauline hydrotheca, mesial to and
surface, consisting firstofashort athecate inter- much smallerthan normal pair. Likewise on the
node without nematothecae and septa, ter- hydrocladium. two medio-superior
minated by slightly oblique node; thereafter nematothecae are often present behind the free
athecate and thecate internodes alternate, their adcauline wall ofthe hydrotheca.
terminal nodes respectively oblique and almost
Remarks
transverse. Thecate internodes 1.5-2 times
See Remarks under//.polymorpha.
length of athecate internodes, without septa;
withfournematothecae:onemedio-inferior,one OccurrenceINFiji
pairlateral,andone medio-superior,small,inthe Suva barrierreef, 7Jul 78 (QMGL10293; BM
axil immediately behind free adcauline wall of 1984.5.17.40); Joske’s reef, on coral rock, with
hydrolheca. Athecate inlernodes without septa, gonothecae, 18 Sep 78.
with one nematotheca.
Hydrothecac cupshaped, taller than wide, ad- WorldDistribution
nate for one-third to one-halfofvertical height, Eastern Indian Ocean and western Pacific,
with w'alls almost straight, flaring slightly to north to Japan (Sagami Bay, Honshu), south to
margin;adcaulineedgeofmarginapproximately Great Barrier Reef.
one-half way up distal athecate internode;
without intrathecal septum. Marginoblique,45- Halopterisdiaphana (Heller, 1868)
55*' to axis. (Fig. 3)
Medio-inferior nematothecae rarely reaching
baseofhydrotheca; two-chamberedandimmov- Anisocalyxdiaphana Heller. 1868: 42
Plumulariadiaphana (Heller): Fraser.1944: 342
able, distal chamber short and scoop-like,
Aniennella diaphana diaphana (Heller, 1868): van
without adcauline w-all, proximal chamber not Gemerden-Hoogeveen, 965:49
sharply demarcated from internode. Lateral Halopteris diaphana diap1hana (Heller, 1868): Ver-
nematothecae on finger-like pedicel, reaching voon, 1968; 58
more or less to thecal margin, two-chambered
and movable, narrowly obconica! with distal Description
chamber shallow, broad and often quite deeply Colony comprising erect stems arising from \
emarginated on mesial side. Medio-superior creeping hydrorhiza; stems reaching 21 mm;
nematotheca small but distinctly two-cham- athecatebasally,thecateandpinnatedistally;the
bered; distal chamber without adcauline wall. two regions separated by a very oblique hinge-
Gonothecae on stem, immediately below type node. Basal internodes of variable length,
hydrothecae; on pedicel oftwo segments; elon- with up to five transverse, slightly annulated
gate and pear-shaped, curving upwards; with nodes; uppermost internodebearinga numberof
two two-chambered nematothecae near base. irregularly arranged nematolhecae. Distal part
Aperture circular, broad andoperculate. dividedbyobliquenodesintothecateinternodes, '
each with one hydrotheca near base and up to
Measurements ((xm) five nematothecae; one medio-inferior, one pair i
Measurements made on BM1988.11.10.6-7 lateral, andoneortw'omedio-superior. Firstpair
QM or two pairs ofhydrocladia subopposite, arising j
and GL10293 respectively. Stem: internode
from short apophyses at sidesoffirst one ortwo
length 360-380, 265-325. Hydrocladium; the- hydrothecac; thereafter, strictly alternating, one
cale internodc 190—240, 175-230; athecate in- per inlernode. Extra short, athecate internodes
ternode 130-140, 100-150. Hydrotheca; may occur sporadically, these having a basal
abcauline length 175—210, 150-180; adnate ad- transverse node and single nematotheca.
caulinelength 140-160, 140-160;freeadcauline Hydrocladia with hydrothecac on upper sur-
length 100-130, 100-120; marginal diameter face; consisting, first, of a very short athecate
160-180, 160-185.Gonotheca(presumed <5 and internode, without nematolhecae or septa, ter- j
9 respectively):operculardiamcter45-54, 162— minated by an oblique node; thereafter, athecate
1
234; vertical height 450-612, 558-738; maxi- and thecate internodes alternate, terminated
mum width 216—234, 252—360. respectively by oblique and transverse nodes.
HYDROIDS FROM
FIJI II 529
FIG. 3. Halopterisdiaphana. A, partofcolony. B, part ofstem and hydrocladia. C, hydrocladium in profile.
D, gonotheca from B. E, gonotheca. A, QMGL10294, Mba. B-D, QMGL10295, Joske's Reef.
Athecate internodes typically longer than the- ing proximad and truncated or, more normally,
cate, without septa but each with a proximal rounded distally. Aperturesmall andoperculate;
nemalotheca. Thecate internodes with three one two-chambered ncmatotheca near the base.
nematothecae: one mcdio-inferior, one pair
lateral; alsowithout septa.
Hydrothecac cup-shaped, tallerthan wide, ad- Measurements(ixm)
Stem: internode length 430-700.
nateforone-halfto two-thirdsofvertical height,
with walls more or less straight, flaring slightly Hydrocladia: thecate internode length 160-225;
j to margin, without intrathecal septum. Margin athecate internode length 170-325.
I oblique, at 45-50° to axis. Hydrothecac: abcaulinc length 200-225; adnate
adcauline length 180-210; free adcauline length
Mcdio-inferior ncmatotheca never reaching
75-115; marginal diameter 190-210.
base of hydrotheca; immovable, two-cham-
bered; distal chamber short and scoop-like, Gmoanxoitmhuecmaewi(d?tihmm1a4t4-u1r6e2m.ale); length324-346;
without adcauline wall. Lateral nematothecae
shortly pedicellate, rarely reaching or overtop-
ping thecal margin; movable and two-cham- Variations
bered; distal chamberobconical, the mesial side Branched colonies rare; branches of same
slightly lower than outer. structureasmainstem,athecateproximally,with
Gonothecae (in our material probably imma- hydrothecae and hydrocladia distally, arising
ture male) on hydrocladia, each immediately from short apophyses on basal part of stem. In
below a hydrotheca; shortly cylindrical; on some colonies, especially the fertile material
pedicel oftwo segments;curvingupward, taper- from Joske’s Reef, athecate internodes of
530 MEMOIRS OFTHE QUEENSLAND MUSEUM
hydrocladia are not longer than thecate inter- consisting of basal athecate and distal thecate,
nodes. hydrocladia-bearingparts: the two separated by
an oblique joint. Basal part variable in length,
Remarks entire or subdivided proximally by one or more
This species appears variable in internode transverse nodes; the uppermostinternode bear-
length, and arrangement and structure of ing anterior nematothecae in two longitudinal
nematothecae. Caribbean material has been series. Distal part divided by oblique nodes into
described by van Gemerden-Hoogeveen (1965) thecateinlernodes,eachwithahydrothecabasal-
and Vervoort (1968). Most of our specimens ly and up to eight nematothecae: one medio-in-
agree with those of van Gemerden-Hoogeveen ferior, one pair lateral and up to five medio-
in having long athecate internodes on the superior, in two longitudinal series. One or two
hydrocladia. However, they lack the superior pairs ofopposite hydrocladia arising from short
nemalotheca in the axil immediately behind the apophyses at sides of the first one or two
free adcauline wall of the hydrotheca, and the hydrothecae; thereafter hydrocladia alternate,
lateralnematothecaedonothavesuchscoop-like oneperinternode.Caulineinternodesmayincor-
>
distal chambers; in these respects our material porate adistal transverse node, forming an athe-
resembles that described by Vervoort (1968) cate internode bearing most of the superior ,
i
from Puerto-Colombia, except that he recog- nematothecae. '
nized a nematotheca in the axil of the hydro- Hydrocladiaconsistingfirstofashortathecate
cladium, absent from our specimens. Other of internode lacking nematothecae and internodal |'
our material, from Joske’s Reef, has short athe- septa, terminated by a more or less transverse
cate internodes and agrees very well with node; thereafter,athecate and thecate internodes
t
Vervoort’s (1968) description, apart from the alternate, ended respectively by oblique and
absence of a nematotheca in the hydrocladia! transverse nodes. Athecate internodes much the |
axil. No axillary nematotheca was indicated by longer, withoutsepta butwith upto three mesial
Nutting (1900) in West Indian material (as nematothecae. Thecate internodes also without
Plumulariaalternata Nutting, 1900) though one internodal septa and generally with three
waslaterdescribedbyFraser(1944).Wheniden- nematothecae: one medio-inferior, not reaching
tifying this as H, diaphana, we have taken ac- base of hydrotheca, and a lateral pair, more or
count of the great variability (we have been less reaching (but not overtopping) the thecal
comparing Pacific and Atlantic material) ap- margin.
parently exhibited by this species: the regular Hydrothecae cup-shaped, squat and shallow,
thecate cauline internodes have been useful to adnate for between one-half to two-thirds of
separate this species from H, constricta Totton, vertical height; with walls more or less straight,
1930, with which it might otherwise be con- widening gradually to margin; not flared.
fused. Withoutintrathecal septum. Margin at45-50°to
axis.
OccurrenceinFiji Medio-inferior nematotheca two-chambered:
Yarawa reef, offMba, underboulder, 8Jul 78 proximal chamber long and probably immov-
(QM GL10294; BM 1984.5.17.41); reproduc- able, distal one short and scoop-like, without an
tive, Joske’s Reef, 18 Sep 78 (QM GL10295). adcauline wall. Lateral nematothecae on short,
finger-like pedicel: two-chambered and mov-
WorldDistribution able, obconical, with distal chamber shallow,
Widely distributed in tropical and warm broad, and only slightly emarginate on mesial
temperate waters. side.
Gonothecae (probably female) on stem, each
Halopteris polymorpha (Billard, 1913) immediately below a hydrotheca: pyriform-
(Fig. 4) ovoid, on pedicel of one segment, curving up-
wards, tapering proximad and rounded distally;
Plumulariapolymorpha Billard, 1913: 24 with two two-chambered nematothecae near
Halopteris polymorpha (Billard, 1913): Millard, base. Aperture circular and operculate.
1975:354
Description Variations
Colony comprisingerectstemsarisingfrom a The hydrocladial hydrothecae may have a
creeping hydrorhiza; stem reaching 12.5 mm; minute one-chambered medio-superior
HYDROIDS FROM
FIJI 11 531
FIG. 4. Halopteris polymorpha. A, part of stem with hydrocladia. B, hydrolhecae and nematothecae. C,
gonotheca. QMGL10296, Suva BarrierReef.
nematotheca located immediately behind the of H. buskii have shorter internodes than pre-
free adcauline wall. viously described and do not have the abcauline
“marginal tooth”depictedby VervoortandVas-
Measurements (p-m) seur. In termsofnematothecal arrangementthey
Measurements are from QM GL10296 and resemble those described by Billard (1913) and
Siboga Sta. 80 (Billard, 1913) respectively. Hirohito (1974) in often having two pairs of
Stem: internode length475-570,-. Hydrocladia: lateral nematothecae; their structure, however,
thecate internode 140-200, 340-380; athecate differs from Billard’sdescription in thatthe dis-
internode 230-280, 380-470. Hydrotheca: ab- tal chamber is not goblet-like and deeply emar-
cauline length 110^140, 135-160; adnate ad- ginate, yet it is not deep and even rimmed as
cauline length 135-150, free adcauline length shown by Vervoort and Vasseur (1977, fig.
d7G72i5o0a-n;m9oe0tmt,heae-rx;ciamam2r(u1gp6mir-no2adbl3ia4abdm.lieyatmeferetme-a,rl3e1)47;25——4l2e12n40g;,tho2p0-e0,r-c52u91l45a.-r 3died0feCin)nt.iitfeOy,iutnrhgsoouaugrrhegmrbaatrdeouraaidla,lamnaesdsi/as/.lhaeplmolalorywgmionbarulptihoasnh.woIewn
havebeen influencedby Billard'sdescriptionof
Remarks specimens from Siboga Sta. 80 (1913, fig. 14A)
Both H, buskii (Billard, 1913; Vervoort and in terms of cup shape and relative internode
Vasseur, 1977) and H. polymorpha (Billard, lengths and by the fact that gonothecae have a
1913; Millard, 1975) are extremely variable in one-segment pedicel, while those of H. buskii
terms of internode length, shape and size of have two segments. The lateral nematothecae,
hydrothecae, and number, arrangement and used by Billard to separate the two species, are
structure of nematothecae. Moreover, they too variable to provide a good diagnostic char-
resembleeachotherveryclosely.Ourspecimens acter. No record ofa two-chambered medio-su-
532 MEMOIRS OFTHEQUEENSLAND MUSEUM
periornematotheca,axillarytoahydrotheca,has prominent swelling, not reaching base of
yet been made for H. polymorpha; they are al- hydrotheca, and two lateral on indistinct projec-
ways minute and single chambered (cf. H. bus- tions, overtopping the thecal margin. Typically
kii). Itseemstousthatthesetwonominal species without internodal septa but with up to five
require comprehensive investigation. perisarcal pegs on the hydrothecal side capable
of so developing: two pegs basally (one below
OccurrencetnFiji and one above papilla of medio-inferior
Among sponge, forereef slope, Suva barrier nematotheca), one distally, and one or two in
reef, 0-20 m, with gonothecae, 19 Feb 80 (QM between.
GL10296). Hydrothecae adnate for more or less entire
vertical height, tubular, wideninga little to mar-
WorldDistributton gin; abcauline wall more or less parallel to
neRoeBdanSke,a,RoAtftrii)c,a,NeSewycChaelleldeosn,iaI.ndonesia (Bor- hIyntdrraotchleacdailalseapxtius,m tahbesemnta.rgin orthogonal to it.
Nematothecae all two-chambered, movable:
Plumularia Lamarck, 1816 distal chamber nearly as deep as proximal one,
funnel-shaped andslightlyemarginateon mesial
Plumularia habereri Stechow, 1909 or adcauline side: not scoop-like.
(Fig. 5) Gonothecae not observed; described as bag-
shaped, smooth, tapering proximally and
PlumulariaHabereri Stechow, 1909: 77 rounded distally; borne at base ofhydrocladium
Plumularia habereri Stechow (1909): Billard, 1913: (Stechow,1909).
42
Plumularia habereriStechow, 1909: van Gemerden- Measurements(fxm)
Hoogeveen, 1965: 60 Stem: internode length 380-1240.
Hydrocladium: internode length 270-360.
Description Hydrotheca: marginal diameter 70-85; ab-
Colony comprising erect stems arising from a cauline height 155-195; adnate adcauline wall
mass of hydrorhizal fibres; stems thick, 140-165; free adcauline wall 10-25.
polysiphonic; reaching 82 mm; branching alter-
nate and in one plane distally, though irregular Variations
and in many planes basally (branches arising Thehydrothecae atthebaseofhydrocladiaare
from both peripheral and axial lubes of stem). usuallyshorterandwiderthanthosedistally.The
Branches polysiphonic to a variable degree athecateinternodesoccurringsporadicallyalong
basallybutmonosiphonicdistally.Axialtubesof the hydrocladium rarely bear a nematotheca.
stem and branches divided by slightly oblique
nodes into internodes of irregular length, each Remarks
with avariable numberofalternate hydrocladial This species has been redescribed in many
apophyses and nematothecae. Apophyses borne varieties by Billard (1913) and van Gemerden-
laterally, each typically with two latero-axillary Hoogeveen (1965). Our material does not agree
nematothecae and one small mamclon on upper with the latter’s description of that from the
surface: occasionally also a superior nemato- Caribbean in that it lacks the short adcauline
theca. In the polysiphonic region of stem and intrathecal septum at the base of the lateral
branches, irregularly scattered nematothecae nematothecae and, moreover, the adcauline cup
occur on peripheral tubes. margin is not developed into upwardly pointing
Hydrocladiatypicallydivided intoregularthe- cusps. Of the forms designated by Billard, f.
cate internodes by slightly oblique nodes; subarmataandf.mediolineatacanbeeliminated
hydrothecaeon uppersurface. Nobasal athecate on account of their excessive development of
internode. Distal region of thecate internodes internodal septa, thebroad internodes,andovoid
occasionally (especially distally) cut offby par- hydrothecae; the latter form also has an ab-
tial or complete nodes into one or more short caulineintrathecal peg: f.mucronatahastoofew
athecateinternodes; thesewithoutnematothecae internodal septa, and the lateral nematothecae
but with an internal, peg-like thickening of the are in distinct cup-like embayments; however,
perisarc, on the hydrothecal side, which may the medio-inferior nematotheca is supported on
develop into a septum. Thecate internodes with a prominent basal swelling. The differences be-
three nematothecae: one medio-inferior on a tween f. attenuata and f. elongata are less clear
HYDROIDS FROM
FIJI II 533
FIG.5.Plumulariahabereri. A,colony.B,partofstem withhydrocladia. C,partofB,enlarged. D, hydrotheca
and nematolhecae,furtherenlarged.OMGL10297, Great Astrolabe Reef.
and, though both are illustrated as having Plumulariapennycuikae Millard and Bouillon, 1973:
numerous internodal septa, a note was made of 85
their absence in younger colonies. In our PlumulariapennycuikaeMillard and Bouillon, 1973:
material the hydrothecae do not narrow distad Millard, 1975: 398
and the margin is not angled as in f.elongata. F.
attenuala was described as being much shorter Description
andperhapsthereforeyoungerthanourmaterial, Colony comprising erect stems arising from
but it still showed internodal septa. Differences stolonale hydrorhiza; stems monosiphonic,
shown byourmaterial areinsufficienttowarrant reaching 8.5 mm, unbranched but bearing alter-
a new form, sowe assign it to f.attenuata. nate hydrocladia inoneplane; basal partwithout
hydrocladia or nematolhecae, very short and
OccurrenceinFiji subdividedproximallybyoneormoretransverse
HeraldPass,GreatAstrolabereef,27m,24Jun nodes, without nematolhecae. Thereafter, stem
78 (QM GL10297; BM 1984.5.17.42). divided by transverse nodes into regular inter-
nodes, each bearing one long hydrocladial
World Distribution apophysis dislally and up to four nematolhecae:
two axillary (one anterior, one posterior), one
Japan (Sagami Bay), Indonesia, Caribbean
inferior and one inferior-opposite; a small
(Curasao). mamelon present on the upper surface of the
apophysis. Internodal septa absent.
Plumularia pennycuikae Millard and Hydrocladia, bearing hydrothecae on upper
Bouillon, 1973 surface, consisting firstofa short basal athecate
(Fig. 6) internode, lacking nematolhecae but with
proximal and distal internodal septa, terminated
Plumularia sp. Pennycuik, 1959: 183 by a very oblique hinge-like joint. Thereafter,
534 MEMOIRS OFTHEQUEENSLAND MUSEUM
FIG. 6. Plumulariapennycuikae. A, part ofcolony. B, partofstem and hydrocladia. C, part ofhydrocladium
in profile. QMGL10298, Ngaloa.
thecate and athecate internodes alternate, ter- onfinger-likeprocess;withshallow,broaddistal
minated respectively by transverse and oblique chamber, slightly loweron mesial side.
nodes. Athecate internodesshorterandwithone Gonothecae not observed but female ovoid to
nematotheca at mid-length; usually with spherical and bearing one egg, borne on
proximal and distal internodal septa, though hydrocladial apophysesofstem (Millard, 1975);
these may be represented by internal peg-like male unknown.
thickenings of the perisarc of the upper wall.
Thecate internodes with three nematothecae:
Measurements(|xm)
onemedio-inferior,reachingabouttothebaseof
Stem: internodelength225-275. Hydrocladia:
hydrotheca,andonepairlateral,notovertopping
thecate internode 165-180; athecate internode
thecal margin; septapresentornot. 125-175. Hydrothecae: abcauline length 115-
Hydrothecae cup-shaped, adnate for ap-
125; adnate adcauline length 90-116; free ad-
proximately one-half vertical height; abcauline cauline length 60-85; marginal diameter
wall straight and free; adcauline wall concave, 115-120.
flaredtomargin; intrathecalseptumabsent.Mar-
gin at45-60'* to hydrocladial axis.
All nematothecae two-chambered and mov- Variations
able. Medio-inferior and cauline nematothecae Some specimens have been observed to have
each with long proximal chamber and short, the first one or two basal internodes with op-
scoop-like distal one. Lateral nematothecae not posite hydrocladia.