A New Species and Two Known Species of Free-Living Marine Nematodes (Nematoda: Monoposthiidae) from Northwest Florida, U.S.A

10 Pages·1994·7.1 MB·English

by  Edwin J Keppner

GuifResearchReports,\ol9,No.1,29^38,1994 ManuscriptreceivedMarch19,1993;acceptedJune1,1993
ANEW SPECIES ANDTWO KNOWN SPECIES OFFREE-LIVING
MARINE NEMATODES (NEMATODA; MONOPOSTHIIDAE)
FROM NORTHWEST FLORIDA, U.S.A.
EDWINJ.KEPPNER
4406GarrisonHoad,PanamaCity,Florida32404
ABSTRACr Twoknownfree-livingmarinenematodes,MonoposthioidesmayriWicserandHopper,1967and
MonoposlhiahexalataChitwood,1936arcredescribedfromsedimentsinSt.AndrewBayandLakePowell,Bay
County,Florida,U.S.A, Onenewspeciesoffree-livingmarinenematode,Monoposthiabaxterin.sp.,isdescribed
fromnonvegetatedsedimentsinStAndrewBay,BayCounty,Florida. Af.baxterin.sp.differsfromtheother
members of the genus in the shape of the gubemaculum which is more similar to that of the species of
MonoposthioidesthanthatofMonoposthia.
Introduction thesettledmaterialandfixedinhotalcohol-formalin-acetic
acidorhot4%formalininseawaterfor24 hours. Speci-
According lo Lorenzen (1981), the family mensweredehydrated'mglycerinebygraduallybringing
Monoposthiidae Filipjev, 1934 contains the genera them1070%ethylalcoholandglycerine(9:1)andallowing
Monoposthia de Man, 1889; Monoposthioides Hopper, the alcohol to evaporate. Specimens were mounted in
xmiNudoraCobh,1920,m6RhinemaCobb,1920. Tlie anhydrous glycerine on Cobb slides. Specimens were
Monoposthiidae are characterized by the presence of a depositedintheFloridaNematodeCollection,University
cuticlewithstrongtransversestriationsformingannuli,and ofFlorida,Gainesville,Florida(UFNC).
a numberof longitudinal cuticular ridgesthatappearas Allmeasurementsaregiven in pm unless otherwise
tVo-sthheaspeesdtrmuacrtkuirnegssa.scVoasntraeeu.sTelheanadmpVhiindcsxa(r1e9c8i9r)curleafrerarnedd sAtbablreedv,iaantdiotnhse;me1a=nilsefnogltlhoowfedbboydythienrannugne.inwpa=renwtihdetshesa.t
aresituatedonthesecondannulus. Thebuccalcavityhas midbody, hd=headdiameteratleveloffirstannulus, cs
awell-developeddorsaltoothandmayhaveoneormore =lengthofcephalicsensilla. ad=widthofamphid. aa=
ventralteethordenticles. anteriorendtoanteriormarginofamphid. be=lengthof
Specimens of two of the four genera of the buccalcavity, nr=anteriorendlonervering, es=length
Monoposthiidae werecollectedfrom estuarine waters in ofesophagus. i=lengthoftail, cw=widthatcloaca, aw
northwestFlorida. Thetwoknownandonenewspeciesof s:widthatanus.av=:anteriorlovulva.a,b,c,V=demanian
frec-hvingmarinenematodesinthegGnemMonoposthioides ratios.
Hopper, 1963andMonoposthiadeMan,1889redescribed
and described, respectively, herein werecollected from
subtidalsedimentsinSt.AndrewBayandLakePowcD,Bay
County,Florida.Thesedimentsfromthecollectionsitesin Taxonomic Account
St. Andrew BayandLakePowellwerenonvegetatedfine
sandandsilt. (AfterLorenzen,1981)
ChromadoridaFUipjev,1929
MonoposthiidaeFilipjev,1934
Materials and Methods
MonoposthioidesHopper,1963
Monoposthioides$nayriWieserandHopper,1967
Sediment samples were obtained with a cylindrical Figures1-12
coresamplerloadepthof4-10cm,dependingonthesite.
Nematodeswereextractedfromthesedimentbyrepeated Description: Body relatively short, broad. Cuticle
decantation. Thesuspendedmaterialfromfourwashings coarselyaimulated;annulioriginateimmediatelyposterior
wasallowedtosettleforl5-20minutes,andthesupernatant to cephalic sensilla; first and second annuli larger than
waterwasdecanted. Nematodeswereremovedalivefrom succeedingannuli. Annuliarecompletelateraltocloaca.
29
30 KHTNOt
Costaein12longitudinalrows;fullydevelopedV-shaped describedashavingasingle,large,dorsaltoothandsmall
costaeoriginatebetweenannuls10and20frDfnanterioroid subventrslprojections. Theseprojectionsarepartofthree
[(38.5(30-56) inmales; 60(50-77)in females). Apexof circlesofsmalldenticlesthatarenoteasilyobserved. The
costaedirectedposleriorlythenreversetoanteriorduection presenceofinnerlabialsensillawasnotmentionedinthe
234.7(218-256)fromantedorendinmales,319.7(301-346) originaldescriptionorfiguredonthedrawings. Themale
infemales. Inmales,lateral,subvential,andventralrows specimensdescribedabovedifferfromtheoriginaldescrip-
ofcostaetermifiateatlevelofclocalopening;remaining tiem ofthemale in that the costae reverse at a greater
rowsterminateimmediatelyposteriortocloacalopening. distancefromtheanteriorend[234.7(218-256)vs.140]and
Infemales,suhventralandventraltowsofcostaetenninate thecephalic sensillaarelonger[22(21-24)vs. 17]. The
atlevelofvulva;remainingrowsterminateposteriortoanal femalespecimensdescribedabovedifferfromtheoriginal
opening.Headwithcircleofsix,$mall,iimerlabialsensiUa descriptionofthefMemalesofM.mayriinthatthe“V”value
immediately adjacent to oral opening. Circle of six islessthanthatof mayri(85-86%vs.9ft;92%)andthe
papilliform outer labial sensill and four long, setiform costaereversesomewhatmoteposteriorlythaninM.mayri
ce{Mic sensilla present. Long cervical, somatic, and (301-346vs.240-250fromtheanteriorend).
caudalscnsillapresentassubdorsalandsubvcncralrowson
eachlateralsuri^ace. Amphidcircular,situatedonsecond
annulus. Buccalcavitywithcyathifoimanteriorchamber MonopostkiadeMan,1889
with circle of 12 small, flap-like structures. Anterior Monopostbiabaxterin.sp.
cliainber of buccal cavity elongate with culicularized, Figures13-21
parallelwalls. Esophaguswithasymmetricalperibuccal
expansion;dorsalsidelarger. Large,muscular,bipartite, Description; Bodyrelativelyshort,broad, (^ticlc
posterior, esophageal bulb present with moderately coarselyannulated;secondannuluswithanteriorbulgeat
cuticuiarizedlumen. Excretoryporenotobserved. Tail locationofamphid. Annuliincompletesubventrallyand
conical,terminalonethirdwithoutannuli; spinneretand ventrallyincloacalregionofmale. Costaeineightlongi-
caudalglandspresent. tudinal rows; dorsal, subdorsal, suhventral, and ventral
Males(a=6); 1=1.15(1.01-1,28). w=40.1(38-43). rowsoriginateontliirdannulus,lateralrowsoriginateon
hd=16(14-17). cs=22(21-24). ad=2.8(2.5-3.n). aa= annulus13-15.Apexofoostnedirectedpostcrioily.reverse
13.8(13-16). be=23.7(19-27). nr=68(61-75). es=144.2 directiononannulus83-88fromameriorend(posteriorto
(125-155), 1=99.8(93406). cw=31<29-34>. a=28.6 esophagealbulb)inmales;costaedidnotreverseinsingle
(26.6-31.6). b = 7.98(7.23-8.53). c = 12,1(10.6-15.3). female examined. In males, laterals, subvenirals, and
Malereproductivesystemdiorehic. Large,non-striated, ventralrowsofcostaetenninateataboutlevelofcloacal
precloat^piocesspresenLSpiculesabsenLSingle,heavily opening; subdorsalsanddorsalrowsofcostaeterminate
cuticuiarizedgubemaculumpresent.46.6(45-48)arc.51(48- posteriortocloacalopening,frifemale.laterals,subvemrals.
56) chord long, arcuate with proximal flange, dorsally andventralrowsofcostaetenninateatvulva;subdorsals
directedprocessofflangelongerthanventmlly directed anddorsalrows terminateimmediatelyposteriortoanal
process. opening. Head withcircle ofsix. setifoim. innerlabial
Females(n=3): 1=1,15(1.11-1.20). w=50(48-51). sensillaimmediatelyadjacenttooralopening.Circleofsix,
hd=16.7(16-18). cs=19.7(19-21). ad=4.0(3.0-5.0). aa setiform, outer labial sensilla and circle of four, long,
= 13.3(1344), be= 25.3(22-27). nr=78(72-82). e5= sedfonncephalicsensillapresent Amphidcircular;situ-
157(144-173). t=94(90-101). aw=25.7(24-27). av= atedonsecondannulus.Longcervical,somatic,andcaudal
979(949-1020). a=22.9(21.8-23.5). b=7.33(6.94-7.85). setifoimsensillapresentassuhventralandsubdorsalrows
c=12,2(11.9-12,6).V=85.3%(85-86).Femalereproduc- on each lateral surface. Buccal cavity with anterior
tivesystemmonodelphic,prodelphic,ovaryreflexed.Vulva cyatfiifonn chamberwith12Qap-likestructures. Large,
withcuticularflap. heavily cuticuiarized, dorsal tooth and three circles of
Specimens: Males. UFNC A157. A158, A159; fe- denticlespresent. Circlesofdenticlesbrokensubdorsally
males,TJFNCA160. anddorsally. Posteriorchamberofbuccalcavityelongate
Locality: St. Andrew Bay, Bay County, Rorida with cuticuiarized, parallel walls. Peribuccal region of
(SODS’SS^N,85'*42M3''W). Nonvegetatedfinesandand esophagus expanded, asymmetrical; dorsal side larger.
sill. Large,muscular,bipartite,esophagealbulbwithwe^y
Remarks;Thespecimensdescribedabovearcconsid- cuiicularizcdlumenprescntposieriorly.Excretoryporenot
eredtobeMonopoithioidesmayribasedontheshapeand observed. Tailconical,terminalonethirdwithoutannuli;
sizeofthegubernaculumofthemale,Iheenlargedsecond Spinneretandcaudalglandspresent.
annulus, and the shape and sizeofthe amphid. In the Males(n=2); 1=1.05(1.04-1.06). w=56(54-58).hd
original descriptionofM. mayri, thebuccal cavity was =22(22-22). cs=26.5(26-27). ad=3.0(3.0-3.0}. aa=
NewandKnownSpeciesofMarineNematodes 31
10(10-10). be = 30.5(29-32). nr = 81(80-82). es = Monoposthikiae. Therefore,thegenus Monoposthioides
157.5(155-160). cw = 36(35-37). l = 55(54-56), a = currently differs from Monoposthia in that the costae
18.8(18.3-19.3). b=6.67(6.50-6.84). c=11.6(11.4-11.8). originatemoreposteriorly,andthegubemaculumisrela-
Reproductive system diorchic. Non-slriated. precloacal tivelylargerandmorearcuateinMonoposthioides.
process present. Spicules absent GubemacuJum large, Monoposthia haxteri n. sp. has characters of both
55(54-56)arc,60(59-61)chordIong,arcuaie,thorn-shaped Monoposthia and Monoposthioides. It is similar to
with inner cuticularization. Distal end expanded with Monoposthiainthat(hecostaebeginonthethirdannulus
ventral process longer than dorsal process. Small teeth andtoMonoposthioidesinthatthegubemaculumisrela-
presentonventralsurfaceofproximaltipofgubemaculnm tively large, arcuate, and the proximal end has a large
inparatypemale,notobservedinholoiypemale. Cuticle ventralprocess.Monoposthiabaxterin.sp.isplacedinthe
inflated in one place on midventral surface anterior to gtnusMonoposthiabasedontheoriginofthecostaeonthe
cloaca. thirdannulus.
Female(n=1): 1= 1.02. w=51. hd= 18. cs=21. Monoposthiabaxterin. sp. isdifferentiated fromall
ad=4. aa=ll. be=29. nr=77. es=144. aw=27. t= othermembersofthegenusMonoposthiaonthebasisofthe
83. av= 914. a=20.0. b=7.08. c= 12.3. V==90%. shapeofthegubemaculum. Itistheonlyspecies witha
Reproductivesystem monodelphic,prodelphic,ovaryre- large,arcuate gubemaculum withanexpanded proximal
flexed. Vulvawithcuticularflap. endwiththeventralproce.s.slongerthanthedorsalproces.s.
Specimens: Male, holotype, UFNC A166; male, Etymology: Monoposthiabaxterin.sp.isnamedfor
paratype,UFNCA168;female,allotype,UFNCA167. Dr. George Baxter, Professor Emeritus, University of
Locality: St. Andrew Bay, Bay County, Florida Wyoming, in recognition of his work and teaching in
(3(>f)833"N,85'^42’43"W). Nonvegeiatcd finesandand aquaticbiology.
silt.
Remarks: Hopper (1963) erected the genus
Monoposthioides to accommodate the species MonoposthiahexataiaChitwoodT1936
Monoposthioides anonoposthia Hopper, 1963 that was Figures22-29
collectedfrom thenortherncoastoftheGulfofMexico.
ThegenusMonoposthioidescanbedifferentiatedfromthe Descriprion; Bodyrelatively short, broad. Cuticle
genera Nudora, Rhinema and Monoposthia in that the coarsely annululated. Second annulus not significantly
costae originate about midlevel of esophagus in largerthan succeedingannulibut withananteriorbulge
Monoposhtioidesratherthanonthesecondorthirdannulus wheretheamphidi.slocated. Annulicompletelaterallyand
asintheotherUireegenera. Inaddition,Monoposthioides ventrallyincloacalregionofmale,buttheseannuliarenot
differs from Nudora and Rhinema hi in the absence of asdistinctasthesurroundingannuli. Costaeinsixlongitu-
spicules. dinal rows; originate on third amiulus. Apex ofcostae
Monoposthioides is most similar to the genus directedposteriorly,reversedirectionimmediatelyposte-
Monoposthia inthat thespiculesareabsentandasingle riortoesophagealbulbinmales,immediatelyanteriorto
well-developedgubemaculum ispresent. Hopper(1963) vulvainfemales. Inmales,subventralandventralrowsof
differenliaiedMonoposthioidesfromMonoposthiaonthe costaeterminateimmediatelyanteriortocloaca;remaining
basis that the costae originate much more posteriorly in rowsterminateposteriortocloaca. Infemales,subventral
Monoposthioides^ the gubemaculum of the male in andventralrowsofcostaelertninatcimmediatelyanterior
Monoposthioidesisrelativelylargerandmorearcuatewith tovulva;remainingrowsterminateatornearlastannulus
a large, ventrally directed process proximally and long ontail. Headwithcircleofsixseiifonninnerlabialsensilla
spinedistally,andthereproductivesystemofthemalein immediatelyadjacenttooralopening.Circleofsixsetiform
Monoposthioidesisdiorchic. Wieserand Hopper(1967) outerlabialsensillaandfourlong,setiform,cephalicsen-
emendedthediagnosisofMonoposthioidestoincludethe sillapresent. Amphidcircular,situatedonsecondannulus.
speciesMonoposthioidesmayriWie-serandHopper,1967. Cervical,somatic,andcaudalsetiformsensillapresentas
InM. mayri,thelong,distalspineofthegubemaculumis subdorsal and subventral rows on each lateral surface.
absentand thedorsal processoftheproximal endofthe Buccalcavity withanteriorcyathiform chamberwith 12
gubemaculumislongerthanthevcnualprocess. flap-likestructures.Anteriorchamberofbuccalcavitywith
Thediorchicmalereproductivesystemcannotbeused single,large,heavilycuticularizeddorsaltoothandpairof
asadifferentiatingcharacterofMonoposthiodes,because small, subventral, denticles; circles ofdenticles not ob-
diorchicmalesofknownspeciesofMonoposthiahavebeen served. Posteriorchamberofbuccalcavityelongatewith
describedbyKilo(1981)andVanreuselandVincx(1989). cuticularized.parallelwalls. Peribuccalregionofesopha-
PlaitandWarwick(1988)usethediorchicconditionofthe gus expanded, asymmetrical; dorsal side larger. Large,
male reproductive system as a character of the family muscular, bipartite, esophageal bulb with weakly
32 Keppner
cuticulaiizedlumenpresentposteriorly.Excretoryporenot KeytotheSpeciesoftheGenusMonoposthiaDeMan,1889
observed. Tailconical;leiminalonethirdwithoutannuli; BasedonMales
spinneretandcaudalglandspresent,
Malea(n=5);1=0.963(0.831-1,06),w=48.4(43-53). Wieser and Hopper (1967) presented a key to the
hd= 18.6(17-19). cs=24,8(22-26). ad=3.1(3.0-3.2). aa species of the genus Monoposthia in which the second
=2104.780.,(481((571.-3713-0-2)12.6.51b)).e. =bcw=25=6..643(762(.266-.2(192)14.-463.)8n.2r).=1=c77=9,26.1(206(.786-0(88-6.9)49.-)1.3c.sa0)==. kanenyuilnucslwudaesddMisotnionpctolsytlhairagetrhtohraankissulcacSecehduilnzg,a1n9n3ul5i.. The
Reproductive system diorchic. Spicules absent. Gcrlach and Ricmiann (1974) listed the species of
Gubemaculumclaw-shaped392(34-43)arc,42.4(36-47) Monoposthia,transferredM.ihorakistatothegenusNudora
chordlong,withproximalexpansionwithdorsallydirected Cobb, 1920,andlistedthefollowingspeciesofthegenus
process, internal cuticularizalion, andarcuatedistal part. MonoposthiaosS2M&. M.arcticaAllgen,1954;M.costata
Singlelarge,subvcntral,papillifoim,precloacalsensiilum (Bastian,1865)DeMan, 1889;M.desmodoroidesAllgen,
presentoneachlateralsurface.Cuticleinflatedmidventially 1959;M.duodecimalataChitwood, 1936;M.falklandiae
intwoplacesanteriortocloaca,particularlyevidentwhen AUgen, 1959; M. grahami AUgen, 1959; M. hexalata
tailisbentventrally.
Female(n=1): 1=0.945. w=67. hd=22. cs=19. Chitwood, 1936: latiannulataPlaiomvA, 1971;M.inielcki
ad=5. aa=11. be=29. nr=80. es=174. aw=26. t= Steiner, 1916;M.mirabilisSchulz, 1932;andAf. miekki
82. av= 788. a=14.1, b=5.43. c=ll.5. V=83%. Steiner, 1916; M. mirabilis Schulz, 1932; and M.
Reproductivesystem monodelphic,prodelphic,ovaryre- paramediteranneaAillgcn, 1959. Thegenusalsoincludes
oflneexefSdep.meacVliueml,evUnasF:wNitCMhalAceus1t6,i5cU,uFlaNrCizA^1fl6a1p.,A162,A163,A164; MonoEpxoasmtihniaatoicotnaloafttahGeaolr’itgsionvaal,d1e9s7c6rifprtoiomntsheofWhthielaebSoevae.
Locality: St. Andrew Bay, Bay County, Florida listed species revealed that the following species of
(3(K)8’33‘'N,8542*43"W)andLakePoweU,BayCounty, Monoposthiashouldbeconsideredspeciesinquirendabe-
Florida(30^16*45"N* 85^*58’50"W). Nonvegetated fine causeonlythefemaleisknownforsomeofthespeciesor,
sandandsilt. ifmalesareknown,probablybelonginthegenusNudora
Remarks:Thespecimensdescribedaboveagreeclosely becauseofthepresenceofspiculesandagubemaculum;M.
withthedescriptiemanddrawingsofM.hexalataprovided arcticaAllgen,1954;M.desmodoroidesAllgen,1959;Af.
intheoriginaldescriptiongivenbyChitwood(1936).They falklandiae Allgcn, 1959; Af. grahami AJlgen, 1959; Af.
differfromtheoriginaldescriptioninthatthereisapairof
paramediterraneaAllgen, 1959.
precloacalpapillaeinthemalesthatwerenotmentione<Ior
figured intheoriginaldescription, CTutwood(1936)de- In the following key to the species of the genus
scribes and figures (Figure 2E) a circle of inner labial Monoposthia,the partofthekeyinvolvingthosespecies
sensillaimmediatelyadjacenttotheoralopeningbutdid withanenlargedsecondannulusismodifiedfromthatgiven
notdescribethecircleofflap-likestructures. byWieserandHopper(1967)toexcludeAf.thorakista.
1. Second annulus distinctly largerthansucceedingannuli 2
Second annulus notdistinctly largerthan succee^gannuli 4
2(1). Cuticle with 12 lon^tudinal rowsofcostae MonoposthiaduodecimalataChitwood, 1936
Cuticle with 6 longitudinal rows ofcostae 3
3(2). Cephalicsensilla less than0.5 head diameter long; amphidsabout0.33 ofcorresponding bodydiameterwide
MonoposthiamiekkiSteiner, 1916
Cephalic sensillaabout l.Oheaddiameterlong; amphidsabout0.17ofcorresponding bodydiameter wide
Monoposthiamirabilis Schulz, 1932
4(1). Cephalic sensillaabsent Monoposthia latiannulata FlsAonovdi, \.91l
Cephalicsensillapresent 5
5(4). Cuticle with 10-20 longitudinal rowsofcoslae Monoposthia costata (Bastian, 1865)
Cuticle with 6or8 longitudinalrowsofcoslae 6
6(5). Cuticle with6longitudinal rowsofcostae Monoposthiahexalata Chitwood, 1936
Cuticle with 8 longitudinal rowsofcostae 7
7(6). Cephalic sensilla less than 1.0 head diameter long; gubemaculum 35.1 pm long, broad, almost straight with
curved distal part and dorsallydirectedproximal MonoposthiaoctalataGal’lsova, 1976
Cephalicsensillamore than 1.0 headdiameterlong; gubemaculum 54-56pm long, narrow,arcuatedistal pan
and broadproximal partwith ventrallydirected processlongerthan dorsallydirectedprocess
Monoposthia baxterin. sp.

34 Keppner
Figures10-13.Monopostkmidesmayri.Fig.lO.Male»anteriorendwithoriginofcostae,scalebar=10m.Fig.ll.Male,buccal
caifity,scalebar=5m. Fig.12, Male,gubemacubiui,scalebar=10m. Fig,13. Monoposihiabaxierin,sp. Fig.13. Male,
gubemaculum,scalebar=10pm.

36 KEPPNBfl
Figures20-21. Monoposthiabaxteiin.sp. Fig.Hk Mak,toffiicavity,scakbar=5m.Fig.21. Male,amphld»scalebar=5m.
Figures22-23. Monoposthia hexakUa Chirwopd, If34. Fig. 22. Male, baccal cavity, scale bar = 5 m. Fig.23. Male,
guberaaculum,scalebar=10pm.

38 Keppner
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libresdelamerduNordetdelaManche.Mem.Soc.Zool. British Fauna (New Series). No. 38. E. J. Brill/Dr. W.
France2:1-10. Backhuys. 502iq>.
Gerlach,S.A.andF.Riemann. 1974.TheBremerhavenchecklist Vanreusel,A.andM.Vincx. 1989. Free-livingmarinenematodes
of aquatic nematodes. Veroff. Inst. Meeresforsch. fromtheSouthernBightoftheNorthSea.IQ.Speciesofthe
Bremerhaven,Suppl.4:1-736pp. MonoposthiidaeFilipjev,1934. Cah.Biol.Mar.30:69-83.
Lorenzen.S. 1981.BntwurfeinesphylogenetischenSystemsder Wieser,W.andB.E,Hoiq)er. 1967. Marinenematodesofthe
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