First records of the genus Berghia Trinchese, 1877 (Opisthobranchia: Aeolidiidae) from Argentina, with description of a new species

8 Pages·1999·4.5 MB·English

by  Claudia Muniain

Avicennia, 1999, 10/11: 143-150
First records ofthe genusBerghia THnchese, 1877 (Opisthobranchia:
Aeolidiidae) from Argentina, with description ofa new species
Primerregistro delgénero Berghia Trínchese, 1877(Opisthobranchia:
Aeolidiidae)para Argentina, descripción de una nueva especie
Claudia Muniain* and Jesús Ortea**
*MuseoArgentinode CienciasNaturalesBernardinoRivadavia. LaboratoriodeMalacolo-
gíayEcosistemas Costeros. Angel Gallardo470. (1405). BuenosAires, Argentina.
**DepartamentodeBiologíade OrganismosySistemas. Universidadde Oviedo. España.
Abstract
ThereisconsiderableconfusiónamongthespeciesofaeolidnudibranchfromtheWestern
AtlanticassignedtotheEuropeanBerghiacoemlescens(Laurillard, 1830),Berghiaverruci-
cornis (DaCosta, 1867) andSpurillaneapolitana (Delle Chiaje, 1823. The genus Berghia
Trínchese, 1877isrecordedatthefirsttimefromArgentina.Ourmaterialiscomparedanddis-
cussedwithspeciesofBerghiafromtheAtlanticandMediterraneancoasts.Weconsiderthat
B. coemlescensdoes notoccurintheWestAtlantic, while the western ocurrence ofB. ve-
rrucicornis requires further investigation. Berghia rissodominguezi is described as a new
specieswithaWesternAtlanticdistributionfromCaribbeantoNorthPatagonianwaters.The
species Spurilla columbina García-Gómez and Thompson, 1990 is included in the genus
BerghiaanditsdistributionisextendedtotheCanaryIsland.
Resumen
ExisteunagranconfusiónentrelasespeciesdenudibranquiosaeolidáceosdelAtlán-
ticoOesteasignadasalasespecieseuropeasB. coemlescens(Laurillard, 1830),B. verruci-
comis(Costa, 1867)andS. neapolitana(DelleChiaje, 1823).ElgéneroBerghiaTrínchese.
1877escitadoporprimeravezparaArgentina.Nuestromaterialescomparadoydiscutido
conespeciesdeBerghiadelacostaAtlánticayMediterránea. LadistribucióndeB. coem-
lescensparaelAtlánticoOesteesconsideradaincorrecta,mientrasqueladeB. verrucicor-
niscomoespecieanfiatlántica,requieredeinvestigacionesfuturas. Seincluyealaespecie
SpurillacolumbinaGarcía-GómezandThompson, 1990dentrodelgéneroBerghia,exten-
diendosudistribuciónhastalasIslasCanarias.
Palabrasclave: Aeolidiidae,Berghia,newspecies,SouthAtlantic,Argentina.
Keywords: Aeolidiidae,Berghia,nuevaespecie,AtlánticoSur,Argentina.
INTRODUCTION
The validity ofthe nudibranch gastropod genera Spurilla Bergh, 1864 and Berghia
Trínchese, 1877 hasbeen questionedby several authors: Rudman (1982) was the first to
considersynonymisingthem. Hepointsoutthattheonly morphological difference between
these generaistheposteriorornamentation on therhinophores, which are lamellated in Spu-
rilla (Eolisneapolitana Delle Chiaje, 1823, type species by monotypy) and papillated in
Berghia (Eolidia coemlescens (Laurillard, 1830), type species by monotypy). He didnot
considered this sufficient difference to sepárate twogeneraand declared Berghia to be a
júnior synonym ofSpurilla, concluding that the Aeolidiidae genera needed a complete
revisión.
143
MuniainyOrtea
Gosliner (1980, 1985) attempted to clarify the characteristics ofthis family, and he
concluded that these genera should remain distinct until more consistent differences are
discovered. Several authors (CerveraandGarcia-Gomez, 1986; Cerveraetal., 1988;
Garcia-Gomez and Thompson, 1990), however, have not adopted Gosliner's sugges-
tion,buthavefollowedRudman's-synonymywithoutcontributinganyadditionalevidence.
On the other hand, in the Western Atlantic numerous records ofboth genera have
beencitedfromtheBraziliancoast(MacFarland, 1909; Marcus, 1955, 1957, 1976; Ríos,
1994), the Caribbean Sea (Edmunds, 1964; Marcus & Marcus, 1970; Thompson,
1980; Edmunds and Just, 1983) and Florida coasts (Marcus, 1972). All ofthese re-
cords havebeen assignedtothe European speciesBerghia coerulescens,B. verrucicornis
(Da Costa, 1867) and Spurilla neapolitana, which have therefore been considered as
amphiatlantic species. However, there are doubts as to the wisdom ofthis conclusión,
because some reports ofthese species are not consistent with the description given by
Tardy (1962), who demonstrated that in Europe there are in fact two species ofBerg-
hia. In the present paper we compared and discussed the species ofthe genus Berghia
recordedatthefirsttime inArgentinawiththe speciesconsideredamphiatlantic until now.
MATERIALANDMETHODS
ThespecimensstudiedcomefromMuséumNationald'HistoireNaturelle,París(MNHN),ma-
terial conserved in the Laboratorio de Zoología, Universidad de Oviedo (LZUO) and specimens
collectedfromPatagonia(Argentina).
Risso-DomínguezdepositedinMNHN(3March 1963),onespecimenlabelledas holotype:Berg-
hiapuelchana from Mar del Plata Port (Buenos Aires). This nominal species are considered no-
men nudum,becausetheoriginal description hasnotbeenfound. Five specimensofBerghia were
collectedfromGulfofSanJosé(PenínsulaValdés),between 1992/1995.
Wealsoexaminedadditional materialofBerghiafromdifferentlocalitiesdepositedinLZUO.
mm
B. verrucicornis: El Puntal (Asturias) 27 Jan. 1978, 1 specimen 7 preserved length, Coll. J.
mm
Ortea.Melenara(LasPalmas,CanaryIslands) 10Mar. 1981, 1 specimen8 preservedlength,Coll.
mm
R. Castillo. Príncipe Island (GulfofGuinea) 16 Feb. 1990, 1 specimen 7 preserved length,
mm
Coll. X. Fernández.B. coerulescens: PuntaMagenesi (Sicily)5Jun. 1990, 1 specimen 12 pre-
servedlength,Coll.G. Rodríguez. Spurillacolumbina: BarrancoHondo,Tenerife (CanaryIsland)
7 Aug. 1996, 1 specimen 34mmpreservedlength, Coll. L. Moro.
Family AEOLIDIIDAE d'Orbigny 1834
Genus Berghia Trínchese, 1877
Berghiarissodominguezi new species
(Fig. 1-2,Píate 1)
Berghiacoerulescens(Laurillard, 1830): Marcus, 1957: 477, figs. 237-246; Edmunds, 1964:
29-30;Marcus, 1976: 9.
Berghiaverrucicornis(Costa, 1864): Marcus, 1972: 304-305; Marcus, 1977: 16;Thompson,
1980: 97; Ríos, 1994: 220,fig. 1090,pl. 76.
?Berghiasp. (A,C)Edmunds, 1968: 213-217, fig. 8-9.
Material examined: Mardel Plata (38°2'11"S, 57°31'37"W, Buenos Aires) intertidal zone,
18Jan. 1961, 1 specimen50mm long inlife (MNHN), Coll. C. RissoDomínguez. Patagonia, in-
tertidal zone, specimens studied live from Gulf of San José (42°25'S, 64°19'W, Chubut), the
length including thetail is: 23 Jan. 1992, 1 specimen 31 mmin length, Coll. C. Muniain; 28Nov.
144
NuevaespeciedelgéneroBerghia
mm mm
1993, 2 specimens45 and50 inlength(dissected),Coll.C. Muniain; 13 Dec. 1995, 2spe-
cimen48 mmlengthand52 mm,Coll. J. PérezBarbería.
Typematerial: Holotype (depositedinMNHN, 13/12/95, 52 mm long, notdissected).
mm
Description: External features: Living animal thin and elongate, 52 in length
(Holotype, MNHN, Pl 1A). General body colour translucent white. There are oblique
bright orange lines on the borders ofthe insertion of the cerata and in front of the rhi-
nophores. Overthe head andbetween the rhinophores is an orange triangle. Translucent
ceras with central reddish-brown diverticulum, ending in a short white cnidosac. An
orange band with a thin subapical red ring around it are present. The digestíve gland
forms a brown-red dorsal digestive mid-dorsal line, visible through the mantle surface
fromthe thirdgroupofceratabacktothe lastcerata. Rhinophores are long, tuberculateon
the lateral andposteriorsides, withcream-whitecoloration andyellow on apical portion.
The translucent oral tentacles have a wide áreaofthe same yellow colourcovering two-
thirds ofthem. The tentacles are long and slender, and approximately twice as long as
the rhinophores. Ceratacylindrical andelongate with arounded apex, uniform in diame-
ter throughout most of their length (Fig. 1A). There are 6-8 clusters ofcerata on each
side, containing between 3 to 24cerataperarch. The anteriormostclustershows the gre-
atest numberofcerata21-24 (holotype) andthe mostcurved shape, decreasing in number
and length towards the tail. The posterior 1-2 clusters consistofrows 1-3 cerata. The in-
conspicuous renopericardical prominence is situatedbetween the first and second cerata
arch, which are further apart than the others. Foot grooved anteriorly, with elongated foot
cornersandtaperinggraduallytothetail.
Internal anatomy: The radulaofaspecimen 50 mmlength (MNHN) contains 27 teeth
with 47-50 deeply pectinate denticles on each side ofthe triangularcentral cusp. The in-
nermost denticles are short so that theprofile ofthe toothis notched; the outermostden-
mm
ticles are uniform in shape (Fig. 2 A).Thejaws are elongate (1.2 long) with a fra-
güe, smooth masticatory border. The salivary glands are shorterthan the buccal mass.
The genital apertures are situated centrally in the first ceratal arch, while the anus is
located within the second arch on the left side. The nephroproct is pre-anal, ventral and
anteriortothe secondceratal arch. Internally, theovotestisconsistof many globularlobe
which decrease in size towards thetail. Aconspicuous ampulla(8 mmlengthand 1.2 mm
width), lies on topoftherestoftheorgans, andisconnectedtoanovoid seminal recepta-
ele. Theprostateiselongated, expandinginto adeferentduct,buttheconjunction between
the twois notwell delimited. The ductis ends in aroundedpenial papillae (Fig. IB, C).
Distribution and Biology: Berghia rissodominguezi is only known from the West
Atlantic, the north and south limits ofits distribution are Florida (Marcus, 1972) and
the GulfofSan José, respectively. This species inhabits warm waters, and can be found
understones in intertidal pools. Itisnotascommon in PatagoniaasSpurilla whichcan be
collected large numberin the same time (summer). When being handled, Berghia risso-
dominguezi is more prone to ceras autotomy than is S. neapolitana.
Etymology: The species is named in honour ofCarlos Risso Domínguez, who co-
llected the first specimen known as Berghia from Argentina.
145
=
Muniain Ortea
>
Figure 1. Berghiarissi\hwtingucz¡newspeeies.A.Dorsalviewofalivinganimal,(scalebar=7
mmVR-C,Dorsalviewofüiegenitalsvstem. B:a,ampulla:al.albumengland: f. témalegland:
ov.ovotestis.C:a.ampulla:f.femalegland:pp.pernalpapilla:pr.prostate;sr.seminalrecepta-
ele:va.vagina.
Figura l. Berghiarissodomingueziespecienueva.A, Mstadorsaldeunanimalvivo. (escala
7mmJLB-C. Mstadorsaldelsistemagenital* B:a,ampolla:aiglánduladelalbumen:/,glándula
femenina:ov.oxxHestis. C:a.ampolla:/,glándulafemenina:pp.papilapeneal:pr.próstata:sr.
receptáculoseminal:va. vagina.
146
NuevaespeciedelgéneroBerghia
DISCUSSION
Western Atlantic specimens ofBerghia have been considered to belong to a single
and variable species, B. coerulescens (Engel, 1925; Marcus, 1957; Edmunds, 1964,
1966; Marcus, 1976). SinceTardy (1962), someofthe oíd records have been re-exami-
ned and assigned toB. verrucicornis. Edmunds (1968) suggested the existence ofsecond
western Atlantic species when he compared the specimens from Ghana and re-examined
the variable Jamaican material cited as B. coerulescens. He assigned the Ghanaian spe-
cimens to B. verrucicornis, and separated the variable material from Jamaica as speci-
mens A, B andC. In all three specimens theceras insertionsareconspicuously marked with
bright orange, an important character absent in B. verrucicornis (Pl. 1 B). Edmunds
(1968) didnotdescribeanew species fromJamaicawhich leadstoconfusión, but suggested
two possibilities, either that "it is possible that there is a single West Atlantic species of
Berghia which is very variable"or"itis possible thatthere are twoormore speciesofWest
Atlantic Berghia, each as distinct as are the two European species". Nevertheless,
Thompson (1980) assigned to B. verrucicornis the material from Jamaica and pointed
out that "both European species ofBerghia have now been recorded from the Caribbean
Figure2. Radularteeth in the speciesofBerghia compared. A. Three median teeth in Berghia
rissodominguezi(paratype, MNHN). Scalebar=10um. B. Berghia verrucicornisfrom Asturias
(North Spain). Scalebar=10um. C. Berghia verrucicornisfrom Las Palmas (Canary Islands).
Scalebar=10um. D. Berghiacoerulescens from Sicily. Scale bar=100 um.
Figura2. Dientes radularesen lasespeciesde Berghiacomparadas. A. Three median teeth in
Berghia rissodominguezi(paratype, MNHN). Scale bar=10um. B. Berghia verrucicornisfrom
Asturias (North Spain). Scalebar=10um. C. Berghia verrucicornisfrom Las Palmas(Canary Is-
lands). Scalebar=10um. D. Berghiacoerulescensfrom Sicily. Scale bar=l()() um.
147
Muniainy Ortea
Seabut the\ ha\e not been consistently recorded underthe corred ñames". As in otherdes-
criptions of Wesl Atlantic specimens, he deseribed the bright orange lines at the ceras
msertions, and drew a radula tooth with long and slender denticles. reliable characters
present in Berghia rissodominguezin. sp. We examined one specimen from Principe Is-
land and. the vermilioncolourtothe rhinophores. the small size and the radularmorphology
confirm that it is the same species recorded by EDMUNDS (1968) from Ghana. Principe
is the southern point ofdistribution cited for B. verrucicorrúson the eastem Atlantic coast.
The main differences between B. rissodomingueziand B. verrucicorrús are: B. risso-
domingueziis larger. has conspicuous orange lines at the ceras insertions. white-creamco-
lour rhinophore papillae, yellow tips to the tentacles. elongated cerata. a greater number
of radular teeth and longer denticles (Fig. 2A. B. C). Berghia rissodominguezi differs
fromB. coendescensprincipallyinthecolourpattemandtheradulamorphology(Fig.2A.D).
Anotherwestem atlantic species ofBerghia is B. creutzbergiMarcus & Marcus. 1970.
in which the radularteeth have altérnate large and small denticles. and there is noorange
pigment (EDMUNDS &Just, 1983). which isclearly different fromB. rissodominguezin. sp.
From material studied in the present paperwe have transferredthe species SpurUIaco-
lumbinaGarcía-Gómez& Thompson,1990tothegenusBerghia. Thisspecieswasdeseribed
from the southern Spain (Andalusian coast). extending now to the Canary Islands.
Based on evidence from numerous record we can ask. are European species ofBerg-
hia present in the Westem Atlantic and are Berghia coendescens and B. verrucicomis
really amphiatlantic species ?. Following the authoritative review ofTardy (1962) we
considered that B. coendescens was nevercorrectly recorded in reports from the westem
Atlantic. Therefore. we suggest that the distribution ofB. coendescens is eastem Atlan-
tic (France and northem Spain) and Mediterranean. The westem presence oí\ Berghia ve-
rrucicomis is more problematic because some authors mentioned characteristics inter-
mediate between B. verrucicomis andB. rissodominguezi (Edmunds. 1968 specimen B).
Inconsequence. the valid presenceofB. verrucicomis in the westem Atlantic needs furt-
herinvestigation.
In azoogeographical discussion Edmunds (1968, 1977) cites 37 speciesofGhanaian
opisthobranehs ofwhich 16 oceurin the westem Atlantic, and he maintains Berghia ve-
rmciconüsasbeingamphiatlantic initsrange. He suggeststhat the floating tree trunks with
coelenterate polyps could easily transpon aeolony ofaeolids across the Atlantic Ocean.
Templado etal (1990) included both Berghia coendescens and B. verrucicomis in
theirlistofamphiatlantic species.but theyconsideredthat transatlantic dispersal eitheras
larvaoron floatingobjeets as unlikely. They conclude that is more probable that the east
andwest Atlantic forms are inprocess ofspeciation resultingeitherin twodistinct species
orin two populations with sufficientdifferences to merit subspecific rank. The San José
Gulf perhaps represents the southern boundary for the subtropical species B. rissodo-
Plate 1 (right). Photographsofliving animáisofBerghia. A. Berghiarissodominguezi,Gulfof
SanJosé.Chubut. Argentina(Holotype. MNHN). B. Berghiaverrucicomis. BahíadeAlgeciras,
Spain. C. Berghiacoendescens. Sicily. Italy.
Lámina 1 (derecha). Fotografíasdelosanimalesvivos¿feBerghia. A. Berghiarissodominguezi.
GulfofSanJosé. Chubut.Argentina(Holotype. MNHN). B. Berghiaverrucicomis.BahíadeAl-
geciras, Spain. C. Berghiacoerulescens.Sicilia. Italia.
148
Nuevaespeciedel géneroBerghia
.
MuniainyOrtea
minguezi,justCape Hatteras is the northernboundary formany othersubtropical marine
invertebrates (Berggren & Hollister, 1974, cited in Templadoetal., 1990).
ACKNOWLEDGEMENTS
WeareverygratefultoDr.AngelValdésforconstmctivecommentsandDr.MalcolmEdmunds
forhis critical review ofthe manuscript and the improvement ofthe English. Many people kindly
gavespecimensandphotographs(García-Gómez,J. C; Villani,G.;Martínez,E.;Moro,L.;Fernán-
dez,X.andCastillo,R.).A.Quintana(MicroscopicalScanningService,UniversidaddeOviedo)as-
sistedusinSEMphotos.ThisresearchhasbeensupportedinpartbytheSecretaríadeCienciayTéc-
nica (Univ. de laPatagonia SJB, doctoral grant), Fundación Antorchas andConicet through an in-
vestigationsubsidyandpostdoctoralfellowshipbytheformerauthor.
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