Description Of Eunice Weintraubi And E-Wui, Two New Species Of Eunicid Polychaetes From Northern Gulf Of Mexico

11 Pages·1998·3.1 MB·English

by  H Lu

PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
lll(l):230-240. 1998.
Description ofEunice weintraubi and E. wui, two new species of
eunicid polychaetes from northern GulfofMexico
HuaLu and KristianFauchald
(HL,FK)DepartmentofInvertebrateZoology,NationalMuseumofNaturalHistory,Smithsonian
Institution,Washington,DC20560,USA. (HL)DepartmentofBiologicalSciences,theGeorge
WashingtonUniversity,Washington,DC20052(USA).
—
Abstract. Eunice weintraubi and Eunice wui are described from shallow
waters of the Gulf of Mexico and variability of morphological characters is
discussed. Becauselargenumbersofspecimensareavailable, somefeaturesof
the ontogeny ofEunice wui are also noted. The morphological characters of
two related species, Eunicefauchaldi and Eunice multicylindri are compared
to each other andtoEunice wui.
Eunicid polychaetes from the Gulf of arepaireddorsallips.Thisfindinghascon-
Mexico were studied by Gathof (1984) sequences forourunderstanding oftheeu-
based on benthic surveys offFlorida, Lou- nicid prostomium. The anterior end ofthe
isianaandTexas.Thespecimensfromthese headineunicidsisusuallynotchedorbifid.
surveysandother, similarsurveyswerede- Positionally, this notch corresponds to the
posited in the Smithsonian Institution. A cleft between the dorsal lips of the onu-
study intended to verify the accuracy of phids. If the cleft portion of the eunicid
identificationsshowedthatmanyofthepre- headcorrespondstotheonuphiddorsallips,
vious identifications were inaccurate at the the position ofthe antennae can no longer
species level. The specimens here studied beconsideredoccipital. Insteadtheeunicid
were in part those reported by Gathof antennaebecomelocatedinmuchthesame
(1984), butmuchofthematerialhasnever position as in other polychaetes (e.g., he-
before been reported in a systematic study. sionids, syllids and scale-worms). The eu-
The morphological terminology was de- nicid prostomial appendages are here re-
fined in Fauchald (1992) except for inter- named to include a median and pairedlat-
pretation of the prostomial appendages. eral antennae and a pair of palps usually
Traditionallythesehavebeenconsideredas found lateral to and in front of the lateral
one to five occipital antennae; terms such antennae.
asouterlateral,innerlateralandmedianan- All the specimens were observed under
tennaehavebeenused(Fauchald 1992used stereo and compound light microscopes;
theabbreviationsAI-AIII)fortheantennae, sketchesfortheillustrationsweremadeus-
and other terms may be found in the liter- ing cameralucida.
ature(Fauvel 1923, Hartman 1944).Orrhage
(1995),basedoninnervation,demonstrated Euniceweintraubi, new species
tmhoaltotghoeuosutweirtlhatpearallpsanitnenontaheer(=poAlIy)chaareetheos-. Materials exFaimgisn,edl.a—-h,Ho2lotype: USNM
Consequently, the eunicids have three an- 090037,offPanamaCity,Florida,MAFLA,
tennae: amedianantennaandpairedlateral 37m,STAV-2528,29°54'59"N,86°04'59"W,
antennae. Orrhage also suggested that the Feb. 1978. Paratype: USNM 090037 (n =
so-calledfrontalantennae(Fauchald1982a) 1, STA v-2528); USNM 090039 (« = 3,
orfrontal palps (Paxton 1986) ofonuphids STA 2528).
VOLUME 111,NUMBER 1 231
0.1mr
Fig. 1. Euniceweintraubi,newspecies: a,anteriorend(ParatypeUSNM090039),lateralview;b,limbate
chaeta; c, pectinate chaeta; d, compound falciger; e, hammer-headed aciculae, 30th chaetiger; f. subacicular
hook.25thparapodia;g,25thparapodium,anteriorview;h,maxillae(ParatypeUSNM090039).
»
PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
26- o
o Br
a Hk
24-
G
CD
-£Q22-
-1—
§5 20- G
E
WCD
18- O O A A
AAA
16-
1 1 1 1 1 1 1
1.2 1.4 1.6 1.8 2.0 2.2
mm
Body width, (include parapodia;
Fig. 2. Thesize-dependentvariationoftheendingpositionofchaetigerwithbranchiae(Br)andthestart
positionofsubacicularhook(Hk)intypespecimensofEuniceweintraubi,newspecies.
—
Description. The holotype (Fig. la) is palps reachfirstchaetiger. Lateralantennae
acompletespecimenwith74chaetigers,the with ten articulations and reaching third
total length is 13.5 mm; the first 10 chae- chaetiger. Median antenna with 14 articu-
tigersmeasure 1.8mminlength,thewidest lations, it reaching chaetiger 6. Anterior
part measures 1.6 mm without parapodia ringofperistomiumabout%totallengthof
(2.1 mmwithparapodia).Aspreserved,the peristomium; separation between first and
specimen ispalewithoutdistinctcolorpat- second ring is clear dorsally and ventrally.
terns. Peristomial cirri with several articulations,
Distalendofprostomiumclearlynotched reachingposteriorendofprostomium.
(i.e., a sulcus present, butvery short). Pro- Anterior notopodial cirri finger-shaped,
stomiumshorterandnarrowerthanperisto- alwayslongerthanventralcirri, withindis-
mium, a little less than halfthe length of tinctarticulations. Firsttwopairsofventral
peristomium. Onepairlargeblackeyes sit- cirri slender; ventral cirri with ovate base
uated outside lateral antennae behind the from thirdparapodiumto middleregionof
palps. Palps and antennae evenly spaced. the body, becoming digiti-form towardthe
Palps a little thinner than antennae. Styles posterior.
ofantennae and palps with moniliform ar- Branchiae first appearfrom fourth chae-
ticulations thatbecome drop-shaped distal- tiger; end on chaetiger 26. Where best de-
ly. Palpostyles have four articulations and veloped, around chaetiger 10, pectinate
VOLUME 111,NUMBER
branchiae with fourfilaments, first andlast revision of the genus Eunice by Fauchald
several (Fig. lg) branchiae with single fil- (1992), these specimens differfromE. an-
ament. Both branchiae and individual fila- tennata in the following characters: Bran-
ment shorterthannotopodial cirri. chiae are present from chaetiger 4 in E.
Limbatechaetae(Fig. lb)marginallyser- weintraubi and not until chaetiger 7 in E.
rated. Pectinate setae (Fig. lc) with 6-9 antennata;theyarepresentonlessthanhalf
teeth, one outer tooth slightly longer than ofthe total chaetigers inE. weintraubiand
other teeth. Compound falcigers (Fig. Id) are present to near the posterior end in E.
withtwoteeth; distaltooth stronglycurved antennata. Furthermore, the limbate setae
andpointingin same direction asproximal are marginally serrated in E. weintraubi,
tooth. Proximal tooth slightly larger than ratherthan smooth as inE. antennata.
distalone. Guardslackmucros,butdistally Eunice weintraubiresemblesEunicepa-
asymmetrically bluntly pointed andbasally peetensis Chamberlin from Tahiti and Eu-
serrated. Shaftsofcompoundfalcigersmar- nice pellucida Kinberg from the West In-
ginally serrated, with adistinct core. Pseu- dies. It differs from E. papeetensis in that
docompound falcigers and compound spi- ithaspectinatebranchiae;inE.papeetensis
nigersabsent. Neuropodiausuallywithtwo the branchiae are palmate. E. weintraubi
yellow aciculae; they blunt-tipped anteri- has branchiae from chaetiger 4; E. papee-
orly, becoming hammer-headed (Fig. le) tensis has branchiae from chaetiger 6. Eu-
from about chaetiger 20, becoming blunt- niceweintraubidiffersfromE.pellucidain
tipped or pointed in last few chaetigers. that eyes are present rather than absent.
Subacicular hooks (Fig. If) present from Branchiae always appear from chaetiger 4
chaetiger 18; always single, yellowandtri- inE. weintraubiratherthanfromchaetigers
dentatewithdistincthoods. Theteethform 5-6asinE.pellucida.Themaximumnum-
acrestandincreaseinsizefromdistaltooth berofbranchialfilamentsisonlyfourinE.
to proximal tooth. weintraubi, rather than eight as in E. pel-
Two pairs of anal cirri present; dorsal lucida, in similarly sized specimens. Final-
pair long and finger-shaped and as long as ly, the median antennal style has up to 30
last seven chaetigers; ventral pair only % rings in E. pellucida and only 14 in E.
length ofdorsalpair. weintraubi. —
Maxillae not examined in holotype; in Etymology. The species is named for
paratype(USNM090039,fig. lh),maxillae the late Dr. Robert Weintraub, formerPro-
formula: 1 + 1, 8 + 6, 7 + 0, 11 + 8, 1 fessorofZoology,GeorgeWashingtonUni-
+ 1. versity, for his contribution to systematic
Variat—ion of morphological characters zoology.
(Fig. 2). In all five specimens examined,
the starting position ofthe branchiae is al- Eunicewui, new species
ways chaetiger 4; but the ending position Figs. 3a-h, 4-6
appearssize-dependent,varyingfromchae- —
tiger 18 to 26. The maximum number of Materials examined. Holotype: USNM
branchialfilamentsisthreeorfour.Thefirst 129729,offFlorida,GulfofMexico,SOFLA,
occurrence of subacicular hooks also ap- 14m,STA52,25°17'48"N,81°39'48"W, 10
pearssize-dependent,startingfromchaetig- Dec. 1982. Paratypes: GulfofMexico, off
eirnc1l6udiinngap1a.r4apmomdi-a,w)idsepe(catimtehnewtoidcehsatetpiagretr, F2l4ormi,da,STSAOF2)L,AU:SUNSMN1M1201900303(n2 =(n2=, 186,
18Diinscaus2s.i1onm.m—-Twhiedespsepecciimmeenns.ofE. wein- mm,, SSTTAA 4532)),, UUSSNNMM 112299777279 ((nn == 4302,, 1144
trauhistudiedbyGathof(1984)wereiden- m, STA 52), USNM 130071 (n = 17, 14
tifiedasEuniceantennata.Accordingtothe m, STA 52), USNM 130126 (n = 5, 14m,
PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
Fig.3. Eunicewui,newspecies:a,anteriorend(ParatypeUSNM129729),lateralview,b,32rdparapodium,
anteriorview;c.limbatechaeta;d,pectinatechaeta;e,compoundfalciger;f,aciculae;g,subacicularhook,32rd
parapodium;h,maxillae,(paratypeUSNM 129729).
» 1
VOLUME 111,NUMBER 1
40- g EWh A
^A A
a EWb AA A
A
35- A
AA
30 AA
CD
-Q
E
C3 ?5 O O (DOO G O
O O O
«C*— O
AA O G
CD 20 O G
E OG G
G G
D)
CD GG
CO 15 A
2 * o
CD
10 t
- --
-I
1
20 40 60 80 100 120
Segment number of complete specimen
Fig.4. Relationshipsbetweenthefirstoccurrenceofthesubacicularhook(EWh),theendingpositionofthe
branchiaedchaetiger(EWb)andthenumberofchaetigersinEunicewui.
STA 52), USNM 130185 (n = 1, 14 m, widestpart 1.1 mm withoutparapodia(1.8
STA52),USNM 130254(n=5 14m,STA mmwithparapodia).
52), USNM 130330 (n = 21, 14 m, STA Prostomium anteriorly rounded; median
52),USNM 130424(n = 3, 14m,STA52), sulcus very shallow dorsally butforming a
USNM 130515 (n = 5, 14 m, STA 52), deep groove on ventral side. Prostomium
USNM 130551 (n = 11, 10 m, STA 50; slightly narrower than peristomium, about
Gulf of Mexico, Texas, Southern Bank, same length and about Vi depth ofperisto-
STOCS:USNM090033(n= 1,82m,STA mium; small specimens with relatively
SB3, 27°26'06"N, 096°31'47"W, Dec. thickerprostomia.Onepaireyespresentbe-
1976), USNM 090034 (n = 1, 75 m, STA hind palps. Palps and antennae similar in
HR1), USNM 090035 (n = 1, 75 m, STA thickness;palpsandlateralantennaeslight-
HR1), USNM 090036 (n = 6, 75 m, STA lyclosertoeachotherthanlateralantennae
HR1). — are to median antenna. All styles with cy-
Description. Holotype specimen (Fig. lindrical rings. Palps with six rings and
3a) complete, with 110chaetigers,tapering reachingmiddleofsecondperistomialring.
abruptly from the posterior part. Length is Lateralantennaewithnineringsandreach-
about 25 mm; first ten chaetigers 2.3 mm; ingposteriorendofchaetiger4.Medianan-
» 1
PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
o EWbr
CD
-Q A EFbr
E
V EMbr
O GO O O
-ci—
CD
CO 4 © AAA
CD
CO
!oc O g£/SO/A /PhA x>
c
CO
i—
-Q
OGD GKDO A v^ V
E
E
x 0©O A
(D
CO
--
"T"
I
20 40 60 80 100 120
Segment number of complete specimen
Fig.5. Relationshipsbetweenthemaximumnumberofbranchiaefilamentnumberandthenumberofchae-
tigersforEunicewui,newspecies(EWbr),E.fauchaldi(EFbr)andE.multicylindri(EMbr).
tenna with 11 rings andreaching chaetiger arrangement from chaetigers 14 to 23.
7. Firstperistomialringisapproximately% Branchiae present on approximately % of
totallengthofperistomium.Peristomialcir- total numberofchaetigers. Mostbranchiae
ri small, with about six articulations and (stem + filament) slightly longerthan dor-
reachingmiddleofprostomium. salcirriexceptonfirstseveral andlastfew
Dorsalcirrilongdigiti-form, alwayslon- branchiatedchaetigers.
ger than ventral cirri; become slender in Limbatechaetae(Fig.3c)marginallyser-
posteriorend ofbody. Anteriordorsalcirri rated. Pectinate chaetae (Fig. 3d) with one
with irregular articulations. Ventral cirri lateral tooth much longer and thickerthan
withovateinflatedbasesinanterior-median otherteeth;numberofteethvariesfrom5-
parapodia; inflatedbases decreasinginsize 8. Compound chaetae (Fig. 3e) yellowand
from about chaetiger 30 (Fig. 3b). Ventral bidentate;guardswithshortbluntlypointed
cirridigiti-formposteriorly. heads andbasallyserrated,lackingmucros;
Branchiae begin on chaetiger 3, end at edge of shaft also serrated. Pseudocom-
chaetiger38.Firstfourandlastbranchiated pound falciger and compound spiniger ab-
chaetigers withonlyone filament, allother sent.Aciculum(Fig. 3f)alwayspaired;dis-
branchiae with at leasttwo filaments anda tally bluntly pointed, some with a pointed
maximum of five filaments in a pectinate sheath. Subacicularhooks (Fig. 3g) startin
»
VOLUME 111 NUMBER 1
2.4-1
O EWr
2.2- A EFr
V EMr
2.0-
o
o
05 1.8- v Zk
D-•— 0°o 00 t& AA V
> 1.6- A
A
/A
<0
1.4-
C
CD ° ° ©0 o o
1.2- O O o O
O
GO
1.0-
-r~
1 1 1
20 40 60 80 100 120
Segment number of complete specimen
Fig.6. RelationshipsbetweentheLength/WidthratioandthenumberofchaetigersinEunicewuinewspecies
(EWr),E.fauchaldi(EFr)andE.multicylindri(EMr).
chaetiger25;yellowandtridentate;teethin tainontogeneticpatterns.Thesepatternsin-
a crest increasing in size from distal to clude the following:
proximal tooth. Subacicular hooks always Palps: In USNM 129777, there are two
single except where replacement hooks completejuvenileswith26 and27 chaetig-
have formed; stouterthan aciculae. ers respectively; both of these have three
Twopairsanalcirripresent;largerdorsal antennae but lack palps. In the same lot,
pairisaslongaslastfivechaetigers,ventral there are two complete specimens, with37
paironlyVt, lengthofdorsal one. and38chaetigersrespectively,inwhichthe
Maxillaenotexaminedinholotype;max- palps are present. Similarly, in USNM
illae ofparatype (USNM 129729, Fig. 3h) 129972 a 34-chaetiger specimen has the
poorly sclerotinized, nearly transparent; threeantennaeandthepalps.Consequently,
with formula: 1 + 1, 11 + 9, + 8, 11 + it appears that palps of E. wui do not
9, 1 + 1. emerge until they have reached more than
Va—riation in morphological charac- 27, butfewerthan 34 chaetigers.
ters. 168 specimensexamined,with36of Peristomial cirri: Specimenswith26and
these complete, including both juveniles 27chaetigers(USNM 129777)lackperisto-
andadults. Itisthuspossibletodelimitcer- mial cirri; apairofvery shortcirri ispres-
PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
ent in specimens with 34, 37 and 38 chae- creasessteadilyasmorechaetigersareadd-
tigers. The development ofthe peristomial ed. For example, the length ratio is about
cirri appears to be simultaneous with that 1.45 for a 26-chaetiger specimen, 2.08 for
ofthe palps. The length ofthe cirri varies a51-chaetigerspecimen,and 1.25fora116
from a small protuberance in specimens chaetiger one. Thus, before a specimen of
withlessthan34chaetigers,toreachingthe E. wuireaches 50 chaetigers, its lengthin-
first peristomial ring in specimens with 65 creases relatively faster than the width;
chaetigers,whilereachingthemiddleofthe thereafter,itswidthincreasesrelativelyfast-
prostomium in specimens with more than erthanthelength.
100 chaetigers. Basedontheinformationaboutvariation
Eyes: Eyes are present in all specimens, in morphological patterns, we believe it
but change in colorfromlightredinjuve- maybeuseful torecognizethree stages:
niles toblackinlarge specimens. Early juvenile stage, from metatrocho-
Branchial pattern: Branchiae are always phore stage until thejuveniles reach about
present from the third chaetiger indepen- 30 chaetigers. Characteristic of this stage
dentofthe sizeofthe specimen. Thenum- are absence ofpalps and peristomial cirri,
bersofpairsofbranchiaeandthemaximum branchiaewithonly singlefilamentandthe
number of filaments are size-dependent body length growing relatively faster than
(Figs. 4, 5). Forexample, ina26-chaetiger thewidth.
juvenile,branchiaearepresentinchaetigers Latejuvenile stage, fromabout30chae-
3 through 9, all having only a single fila- tigers to about 50 chaetigers. Thejuvenile
ment; ontheotherhand,ina 116-chaetiger retains the branchial pattern and growth
specimen,branchiaearepresentfromchae- patternoftheearlyjuvenile,buthasatthis
tigers 3 through 39, with a maximum of stage developed both palps and peristomi-
five filaments. Usually, E. wuihas amaxi- um cirri.
mumoftwobranchialfilamentsbythetime Adult stage, in which the specimen has
they reach 50 chaetigers, a maximum of atleast50chaetigers. Characteristicofthis
threefilamentsatabout75-80chaetigers,a stage is branchiae with two or more bran-
maximum of four filaments at 90 chaetig- chial filaments and body width increases
ers, andamaximumoffiveoreven sixfil- relativelymore—rapidlythanbody length.
aments whenthey reach 100 chaetigers. Discussion. This species was listed as
Subacicular hooks: Subacicular hooks Eunice vittata (Fauvel 1923, Fauchald
are always single, yellow and tridentate. 1992) by Gathof(1984). It differs fromE.
Thestartingposition(Fig. 4)issize-depen- vittata most notably in that subacicular
dent. They appear from chaetiger 10 in a hooks are always single, notmultiple asin
26-chaetigerjuvenile,butfromchaetiger25 E. vittata. Furthermore, in specimens with
in a 116-chaetigeradult. similar chaetiger counts, the maximum
FromFigs. 4 & 5, the approximatetotal number ofbranchial filaments is strikingly
chaetiger number of an incomplete speci- different:Ina75-chaetigerE.vittataamax-
mencanbeestimatedeitherbythenumbers imum of 12 filaments is present, but in a
ofpairsofbranchiaeorthestartingposition specimenofE. wui,withasimilarchaetiger
ofsubacicularhooks, orbyacombinedes- count, only threefilaments arepresent.
timateusing the abovefactors. Eunice wui resembles Eunicefauchaldi
Length/widthratio:FromFig. 6,itisob- MiurafromJapanandEunicemulticylindri
vious that the length/width ratio ofE. wui ShiskofromtheCaliforniancoast.Paratype
changes during its development. The ratio material ofboth species (20 specimens of
increases with the increasing number of E.fauchaldi, ofwhich 13 are complete; 7
chaetigers, itreaches apeakfora50-chae- specimens of E. multicylindri, of which
tiger specimen. From there the ratio de- three are complete) were available for ex-
VOLUME 111,NUMBER 239
42-
o o
40- O
<D
CO o
!occ 38- oo GO o
2 o
_Q
36-
.C
>-i—i
-C-» 34- A
(ED i
D) 32-
(1)
0)
30- A o EF
(0
_l A EM
28- A
i 1 1 1 ' i I 1 i
85 90 95 100 105 110 115
Segment number ofcomplete specimen
Fig. 7. RelationshipbetweenthenumbersofpairsofbranchiaeandthenumberofchaetigersforEunice
fauchaldi(EF)andE.multicylindri(EM).
amination. Variations in morphological that ofE.fauchaldi (n = 10) is 1.60, and
characters were comparedwith those ofE. E. multicylindri(n = 1, 116chaetigers)has
wui. Figs. 5 and6 show thatE. wuidiffers aratioof 1.71.
fromthesetwospeciesinthefollowingfea- InbothE.fauchaldiandE. multicylindri
tures: in similarly sized (samewidth) spec- branchiaestartonchaetiger3,butthenum-
imens,E. wuihasahighernumberofbran- bersofpairsofbranchiaearedifferent(Fig.
chial filaments than the other two species 7). For example, a 115-chaetiger E. fau-
(Fig. 5). For example, at 100-116 chaetig- chaldi specimen has branchiae from chae-
ers, the average maximum number offila- tigers3through42,butinaspecimenofE.
ments ofE. wui (n = 7) is 5.1; in E.fau- multicylindriwith asimilarchaetiger-count
chaldi (n = 10) it is 3.3, and in E. multi- (116chaetigers),branchiaearepresentfrom
cylindri(onlyonespecimenwith 116chae- chaetigers 3 through 34 only.
tigers) only 3 filaments. The length/width Morphometric studies on polychaete
ratio is different (Fig. 6). For a similarly worms have already been conducted by
sized specimen, the new species appears many workers, including Fauchald (1982b,
stouter than the others. For example, at 1991),Mackie(1984),andSigvaldadottir&
100-116 chaetigers, the averagemaximum Mackie (1986). Thoseprevious papers and
length/widthratioofE. wui(n = 7)is 1.17, thecurrentstudyindicatedthatcertainmor-