A New Species Of Cassidinidea Hansen (Isopoda : Sphaeromatidae) And First Record Of The Genus From The Eastern Tropical Pacific

8 Pages·1998·2.2 MB·English

by  M E Hendrickx

PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
lll(2):295-302. 1998.
A new species ofCassidinidea Hansen (Isopoda: Sphaeromatidae) and
first record ofthe genus from the eastern tropical Pacific
Michel E. HendrickxandMa. del CarmenEspinosa-Perez
EstacionMazatlanUNAM,P.O. Box811,Mazatlan, 82000Sinaloa,Mexico
—
Abstract. Cassidinidea mexicana, a new species, is described from an
abundantmaterialfromthe southeastern GulfofCalifornia, onthe westcoast
ofMexico. The species is closely related to the type species ofthe genus, C.
ovalis (Say) with which it shares a very similar appendix masculina, and an
almostsimilararrangementoftrifidserratedspinesonthedistalmarginofthe
carpusofpereopod7.Theabsenceofdorsalnodulesonpereonites(veryweak,
almost wanting, in ovalis) and the presence ofa single, median elevation on
the pleotelson are other similarities between the two species. It differs from
thisAtlantic species,however,bythepresenceofapairofweakridgesalmost
parallel to thelateralmargin ofthepleotelson, thepresenceofanotherpairof
ridges, inverted "v"-shaped, running fromthe anteriorpart ofthe median el-
evation ofthe pleotelson towards its posterior margin, and the absence of a
clear indentation on the distal margin ofthe exopod ofpleopod 1. The new
species is the firstrecord ofthe genus Cassinidinea intheeastPacificregion.
The subfamily Cassidininae Hansen was "Cassidinidea" group, in having non-flat-
recentlyreviewedbyBruce(1994).Species tened first and second antennule peduncle
of this subfamily of Sphaeromatidae La- articles. Its affinity with the genus Cassi-
treillearesmallandusuallyassociatedwith dinidea Hansen is confirmed by the pres-
shallowwater,estuarineorcoastallagoonal ence of the very long and acute appendix
habitats.Althoughheindicatesthat"...the masculina set on a proximal directed ex-
resolution ofthe status ofthe Cassidininae pansionoftheendopodofmalepleopod2,
mustwaituntilfurtherdataareavailableon theabsenceofarostralpoint,pleonwithout
the [twoothersubfamilies]Sphaeromatinae suturesandarelativelywideepistome.Dor-
andDynameninae" Bruce (1994:1083)im- sal nodules are apparently very weak or
plicitly accepted the validity ofthe Cassi- wanting (as inNaesa ovalisSay, 1818, the
dininae by providing synonymy and diag- typespeciesofCassidinidea),exceptonthe
nosis.Bruce(1994)furtherdividedthegen- pleotelson.
era of Cassidininae into three groups: the TheexactcompositionofthegenusCas-
"Cassidina" group,the"'Leptosphaeroma" sidinidea Hansen is still to be confirmed.
group, and the "Cassidinidea" group. The AccordingtoBruce(1994),severalAtlantic
materialonwhichthis studyisbasedclear- species are probably synonyms of previ-
ly belongs to the Cassinididea group (con- ously described species [e.g., C. ovalis
taining only two genera) for the following (Say, 1818)]. All together, there seems to
reasons: thelateralmarginsofthecephalon be 10valid species, nonefromtheeastPa-
are expanded (not expanded in the Lepto- cific. The presence ofthe herein described
sphaeroma group) and the pleon has only new species along the coast of western
one segment (three segments in the Cassi- Mexico, represents the first record of the
dinagroup).ItisdistinctfromSyncassidina genus Cassidinidea for the west coast of
Baker, the second genus belonging to the America.
296 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
Abbreviationsusedinthispaperare:TL, Sirena (23°09.03'N, 106°19.00'W), Maza-
totallength;coll.,collector;EMU,Estacion tlan, Sinaloa,Mexico,24Apr 1997, 1 male
Mazatlan UNAM Invertebrates Reference (TL2.5 mm), 6 females (TL 1,4-2.7 mm),
Collection; USNM, United States National and 2 ovigerous females (TL 3.4 mm)
Museum,SmithsonianInstitution,Washing- (EMU-4630). —
ton D.C., U.S.A.; QM, Queensland Muse- Descriptionofmale. Bodyovate,about
um, Brisbane, Australia. 1.8 times as long as wide; pereonites 1-7
without sub-median nodules (Fig. 1A).
Family SphaeromatidaeLatreille, 1825 Pleotelson with a median elevation and a
Genus Cassidinidea Hansen, 1905 pair of lateral ridges; another pair of in-
Cassidinideamexicana, new species verted 'V-shaped ridges running from the
Figs. 1-4 anterior part of the median elevation to-
— wards posterior margin of the pleotelson.
Type material. Holotype, 1 male (TL Epistome (Fig. 3F) anterior margin almost
3.0 mm), Estero Sirena (23°09.03'N, straight, reduced, less than halfthe length
106°19.00'W), Mazatlan, Sinaloa, Mexico, of cephalon in dorsal view. Epistome in
24 Apr 1997 (EMU-4072). Paratype, 1 fe- ventral view subrectangular, slightlylonger
male (TL 3.7 mm), same locality, 24 Apr than broad, lateral and posterior sides
1997 (EMU-4073). Paratypes, 2males (TL strongly concave. Cephalon withoutrostral
2.5 and 2.8 mm) and 2 ovigerous females point. Antennulepeduncle(Fig. 2A)with3
(TL4.0and4.2mm),samelocality,24Apr articles; flagellumwith7 articles, long,ex-
1997 (USNM285513). Paratypes,Esteroel tendingslightlybeyondhalfofpereonite2.
Infiernillo, Mazatlan, Sinaloa, Mexico, 14 Antennapeduncle(Fig. 2B)with5 articles;
Mar 1996, 1 male (TL 3.2 mm) and 1 fe- flagellum with 8 articles, slightly longer
male (TL 2.9 mm) (QM W22716). Para- than antennularflagellum.
types, 3 males (TL 2.7-3.1 mm) and 8 fe- Mandiblepalp(Fig. 3B)articles 1 and2
males (TL 1.6-3.7 mm), same locality, 24 with 5 serrated spineseach. Leftmandible
Apr 1997 (EMU-4074) (All specimens, with incisor tooth 3-dentated (an incon-
coll. J. Salgado-Barragan and M. C. Espi- spicuous fourth) and lacinia mobilis (3-
nosa-Perez). — dentated); setal row of 3 serrated setae;
Additionalmaterial. EsteroelInfiernil- molarprocesswithastraightserratedmar-
lo, Mazatlan, Sinaloa, Mexico, 06 Sep gin. Right mandible similarin shape, with
1995, 1 male (TL 2.8 mm), 1 female (TL only one 3-dentated (an inconspicuous
3.4 mm), and 1 ovigerous female (TL 3.1 fourth) incisor tooth; setal row made of3
mm) (EMU-4432) (coll. J. Salgado-Barra- serrated setae andone bifid serratedsetae;
gan and M. C. Espinosa-Perez). Same lo- molarprocess asinleftmandible.Apexof
cality, 14 Mar 1996, 3 males (TL 2.7-3.1 thelaterallobeofmaxillula(Fig. 3D)with
mm), and 3 females (TL 2.8-3.5 mm) 8 non-plumose, non-serrated spines, and2
(EMU-4433)(coll.J.Salgado-Barraganand serrated spines; medial lobe with 4 plu-
M. C. Espinosa-Perez). Estero Caiman mosespines. Maxilla(Fig. 3C)laterallobe
(23°09.20'N, 106°19.93'W) 1 female (TL with4 serrated spines, middlewith4, and
3.5mm)(EMU-4434)(coll.J.Salgado-Bar- mediallobewith5plumosespines(thein-
ragan). Estero el Verde (23°25'N, ner one mounted on a short lobular pro-
106°34'W), Sinaloa, Mexico, 10 Feb 1979, cess) andtwo slendernon-plumosespines.
2 ovigerous females (TL 4.0-4.3 mm) Maxillipedpalp (Fig. 3E) withonly4dis-
(coll. M. E. Hendrickx) (EMU-4435). Es- tinguishable articles; about 7-8-6-7 setae
teroBarron (23°08.87'N, 106°18.78'W),24 on articles 1-4, respectively.
Feb 1994, 1 male (TL 3.0 mm) (EMU- All pereopods with setules on margins.
4436) (coll. J. Salgado-Barragan). Estero Pereopod 1 (Fig. 2C) merus about half as
,
VOLUME 111.NUMBER2
D
Fig. 1. Cassidinidea mexicana, new species. A, Paratype, male, dorsal view (EMU-4074); B, Paratype,
female,dorsalview(EMU-4074);C,lefturopod,male,dorsalview;D,pleotelson,female,lateralview.
long as ischium; merus with one serrated lowermargin;2serratedscalesnearbaseof
spine at superior distal angle; carpus trian- this sub-terminal spine. Pereopod 2 (Fig.
gular, short, about half length of merus; 2D) about 15%longerthatpereopod 1,car-
propodus and ischium sub-equal in length; pusstrongerandlongerthaninpereopod 1
dactylus morethanhalfthe lengthofprop- provided with three large trifid serrated
odus, with one subterminal spine on the spines on superior distal margin; merus
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Fig. 2. Cassidinideamexicana, newspecies,maleholotype(EMU-4072).A,rightantennula;B,rightan-
tenna;C,rightpereopod 1;D,rightpereopod2;E,rightpereopod7.
with a pair of serrated spines at superior pereiopod2,slightlylonger,the4ththelon-
distalangle;inferiormarginsofmerus,car- gest.Pereopod7(Fig.2E)moreslenderand
pusandpropoduseachwith 1 setae.Pereio- longer than pereopod 2; carpus distal mar-
pods 3-4 similarin shape and spination to gin with 5 large trifid serrated spines; is-
VOLUME 111.NUMBER2
Fig. 3. Cassidinideamexicana, newspecies,maleholotype(EMU-4072). A,rightmandible;B, leftman-
dible;C,rightmaxilla;D,rightmaxillula;E,rightmaxilliped;F,epistomeandupperlip,ventralview.
chium, merusandcarpuswith 1-2setaeon 7; these pereiopods slightly increasing in
theinferiormargin;meruswithonesetaeat size from 5th to 7th.
the superior distal angle. Pereiopods 5-6 Penial process subtriangular, ca. 1.3
similarin shape andspinationtopereiopod times longerthan wide (Fig. 4F).
PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
Fig.4. Cassidinideamexicana,newspecies,maleholotype(EMU-4072).A,rightpleopod 1;B,pleopod2;
C,pleopod3;D,pleopod4;E,pleopod5;F,penialprocess.
Pleopods 1-3 (Fig. 4A-C) endopod and dix masculinaofpleopod 2 elongate, slen-
exopodwithplumosemarginalsetae.Distal der, twice (or a little more than twice) as
marginofpleopod 1endopodalmostround- long as distance from the distal margin of
ed, with no clear distal identation. Appen- peduncle to distal margin of endopod,
301
curvedinitsdistalhalf;shaftwithmarginal sionally living on mangrove is C. korpie
spines almost throughout its length; tip Bruce, 1994 (tidalRhizopho—ra).
four-spined. Pleopod 4 (Fig. 4D) without Geographicdistribution. Thespeciesis
marginalsetae;exopodalmostentirelycov- currently known only from the southeast
ered with transverse folds. Pleopod 5 (Fig. coast ofthe—GulfofCalifornia.
4E) without marginal setae; exopod with Remarks. Thenew speciesis strikingly
two scaled patches, scales with 5-12 spi- similarto C. ovalis, thetype speciesofthe
nulesofsub-equallength;endopodentirely genus. It shows a very similar appendix
covered with transverse folds. masculina,andsimilararrangementoftrifid
Uropod exopods as in other species of serrated spines on the distal margin ofthe
Cassidinide—a(Fig. 1C). carpus ofpereopod 7. The absence ofdis-
Female. Body ovate, wider than in tinguishable dorsal nodules on pereonites
male, about 1.6 times as long as wide. All (very weak, almost wanting, in C. ovalis)
characters agree closely to male, including and the presence of a single, median ele-
all pereiopods. No variation ofmouthparts vation on the pleotelson are other similari-
in ovigerous f—emales. ties between the two species. Male andfe-
Etymology. The epithet refers to the male ofC. mexicana show aweakbutdis-
west coast ofMexico where the new spe- tinctlateralcarinaonbothsidesofthepleo-
cies was fi—rstrecorded. telson elevation, and anotherpairofridges
Habitat. Most specimens of C. mexi- (inverted "v"-shaped)runningfromthean-
canawerecollectedfromtheaerialrootsof terior part of the median elevation of the
Rhizophora mangle L., in Estero de Urias, pleotelson towards its posterior margin;
wheretheyliveamongepifauna:themussel none oftheseridges have been reportedin
Mytella strigata (Hanley), the oysterCras- C. ovalis by Bruce (1994). Cassidinidea
sostrea corteziensis (Hertlein), andthebar- mexicana also differs from this Atlantic
nacles Balanus inexpectatus inexpectatus species by the absence ofamarked inden-
PilsbryandBalanuseburneusGould.Spec- tationonthedistalmarginoftheexopodof
imensfromEsteroelVerdewerefoundun- pleopod 1. Two species of Cassidinidea
der a piece of dead wood. Specimens of present ridges on pleotelson: C. monodi
presumablythesamespecieswerealsocol- (Barnard, 1951), known fromSouthAfrica
lected under twigs, on an intertidal mud- and C. korpie Bruce, 1994, fromAustralia.
flat, at Caimanero coastal lagoon, south of Cassidinideamexicanadiffersfromthefor-
Mazatlan(ca.22°55'N, 106°05'W)butwere mer by its widely truncate pleotelson tip
no longeravailable forcomparison. Search (narrower and rounded in C. monodi), the
for material of Cassidinidea in another size and shape oftheepistome (large, sub-
coastal lagoon located much northern, in quadrangular and broader than long in C.
the central part of the Gulf of California monodi)andtheshapeofthepenialprocess
(Estero el Soldado, San Carlos, Guaymas), on 7th sternite (much narrowerin C. mon-
were unsuccessful. The general habitat odi);itdiffersfromthelatterbytheabsence
("mangroves")ofC. mexicanaissimilarto of submedian nodules on pereonites 1-7,
the habitat reported for C. arndti (Ortiz & the absence ofaclearnotch on distalmar-
Lalana, 1980) from Cuba. Bruce (1994: gin of exopod ofpleopod 1, the shape of
1151) erroneously used the same specific theedgeofthemolarprocessofmandibles
name for two Cassidinidea: "C. monodi and, as in the case of C. monodi, by the
(Carvacho, 1977)" [sic] and C. monodi size and shape oftheepistome (large, sub-
(Barnard, 1951). The species of Carvacho quadrangular and broader than long in C.
is in fact C barnardi, found in mangrove korpie) andthe shape ofthepenialprocess
ozfopGhuoardaelmoaunpgele("")... .AsufroulresthrascpienceisesdeoRchcia-- poine).7th sternite (much narrower in C. kor-
—
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AccordingtoBruce(1994: 1083),thela- LiteratureCited
ciniamobilisisusuallypresentonleftman- Barnard, K. H. 1951. Newrecords anddescriptions
dible of Sphaeromatidae but "... it is not ofnewspecie—sofisopodsandamphipodsfrom
always clearifthe distal most spine ofthe SouthAfrica. AnnalsandMagazineofNatu-
spine row [on the anterior margin ofman- ralHistory(12)4:698-709.
dwihbelen]aisdiastirnecdtuclaecdinliaacimnoibailmiosbiilsinsotorprneost- Bruce,t(NrCa.rluiasL.t.—aceJ1ao9:u9r4n.IasloTphooedfa:CNaasStspuihrdaaielnrionHmaiaesttioHdraaynes)e2n8o,:f1A01u970s75--
ent".Inthenewspeciesthelaciniamobilis 1173.
is clearlypresent. Carvacho, A. 1977. Isopodes de laman—grove dela
Guadeloupe, Antilles Francaises. Studies on
the FaunaofCuracaoandotherCaribbeanIs-
Acknowledgments lands 174:1-24.
Hansen,H.J. 1905. Onthepropagation,structureand
TheauthorsthanktheCONABIO(Comi- cQluaasrstiefrilcaytiJoonurnoafltohfeMifcarmoislcyopSipchaalerScoimeindcaee.49:
sion Nacional para el Estudio y Uso de la 69-135.
Biodiversidad, Mexico) for supporting the Latreille,P.A. 1825. Familiesnaturellesduregnean-
research on isopods ofthe Pacific coast of imal, exposes succinctement et dans un ordre
Mpeeoxpilceow(hCoOhNeAlpBeIdOduprrionjgecttheH-p1re7s0e)ntansdtutdyh.e Ortiz,MPa.anr,ails&y,ti5Rq7.u0eR.papL.vaelcana1'.ind1i9c8a0t.ioUnndaenuleeuvrasesgpeencreise.s
Jose Salgado-Barragan provided useful in- deisopodo(Crustacea,Isop—oda)delosmangla-
formation regarding the habitat ofthe new resdelacostasurdeCuba. RevistadeInves-
Tspheeciheasbiatnuds dhrealpweidngsdurairengbytheGrcaoclilaenctoioVnas-. Say,T.tgie1gn8au1cs8i.oNnaeDesessaMc.arr—iiptnJiaoosunr6no:afl16to0hfr-e1te7he4n.AecwasdpeecmiyesofofNatth-e
lenzuela. uralSciencesofPhiladelphia 1:482-485.