FRESHWATER SHRIMP OF THE GENUS MACROBRACHIUM

19 Pages·2007·0.71 MB·English

JOURNALOFCRUSTACEANBIOLOGY,27(2):351–369,2007
FRESHWATER SHRIMP OF THE GENUS MACROBRACHIUM (DECAPODA: PALAEMONIDAE)
FROM THE BAJA CALIFORNIA PENINSULA, ME´XICO
Luis Herna´ndez, Gopal Murugan, Gorgonio Ruiz-Campos, and Alejandro M. Maeda-Mart´ınez
(LH,GM, AMM-M)Centro deInvestigaciones Biolo´gicas del NoroesteS.C., MarBermejo 195,
Col. PlayaPalodeSantaRita, LaPaz, Baja California Sur,C.P. 23090,Me´xico
([email protected]; [email protected]);
(GR-C) FacultaddeCiencias, UniversidadAuto´noma deBajaCalifornia
Ensenada,BajaCalifornia, C.P. 22800,Me´xico ([email protected])
(correspondingauthor (AMM-M): [email protected])
ABSTRACT
FreshwaterdecapodslikethepalaemonidrivershrimphavereceivedlittleattentionintheBajaCaliforniaPeninsula,Me´xico.Fromthe
firstformalreportin1878tonow,onlythreeMacrobrachiumspecieshavebeenreported(M.americanum,M.digueti,andM.tenellum)
fromthepeninsulainonlythreebasins.Wemadeataxonomicstudyoffreshwatershrimp,whichincludedanextensivefieldsurveyat81
sitesdistributedonboththePacificandtheGulfofCaliforniaslopesandarevisionofmaterialfromtheareathathadbeendepositedin
scientificcollections.WereportsixspeciesofMacrobrachiumbyaddingM.hobbsi,M.michoacanus,andM.olfersii.Wealsodiscuss
someaspectsofthediversityandconservationofthesespeciesinthepeninsulaandprovideanidentificationkeyfortheMacrobrachium
shrimpofnorthwesternMe´xico.
INTRODUCTION wide geographic distribution, and commercial importance
(Holthuis, 1952; Villalobos, 1982). The species of Macro-
TheBajaCaliforniaPeninsulainnorthwesternMe´xicoisthe
brachium have a primary tropical distribution (Hedgpeth,
second longest and believed to be the most geographically
1949;Jayachandran,2001).IntheAmericancontinent,they
isolatedpeninsulaintheworld(DurhamandAllison,1960).
have been reported from the Illinois River basin, USA
SurroundedbytheGulfofCalifornia(SeaofCorte´s)andthe
(Bowles et al., 2000) to Argentina (Rodr´ıguez De La Cruz,
Pacific Ocean, it extends about 1500 km from the Me´xico-
1965;Acun˜a,2002)andfromtheGulfofCaliforniatoPeru´
U.S.A. border in the north to Cabo San Lucas in the south.
(Holthuis, 1952; Wicksten and Hendrickx, 2003).
Its average width is about 70 km. The peninsula is
The genus Macrobrachium is distinguished from other
politically divided into two Mexican states, Baja California
palaemonid genera by the following morphological traits;
and Baja California Sur, with the interstate border at the
288N parallel. The peninsula has a wide range of climatic carapace with a projecting rostrum, mandibles with molar
conditions, though arid conditions are predominant. The process furnished with a triarticular palp, first pair of
general physiography is characterized by outstanding pereiopods chelate and slender and as long as the carapace,
mountainous chains, which extend along the peninsula, secondpairchelateandofteninmaleslongerthantheentire
withnumerousbasinsandcoastalplainsonboththeGulfof body, posterior three pairs of pereiopods simple, telson
California and the Pacific slopes. There are no permanent triangular, terminating in asingle tip (Bate, 1868; Holthuis,
rivers,butfreshwatersprings,intermittentcreeks,andsmall 1952; Mossolini and Bueno, 2003). They also have hepatic
water bodies occur forming unique oasis ecosystems and antennal spines and two pairs of spines on the dorsal
(Arriaga and Rodr´ıguez-Estrella, 1997). surface of telson (Hedgpeth, 1949; Holthuis, 1952).
Mayaetal.(1997)recognized184oasesinthepeninsula, Holthuis (1952) concluded that only a few characteristics
butonly77wererecordedtohavesurfacewater.Besidesthe are available for identification of the species of Macro-
presenceoffreshwater(surfaceorinterstitialsoilwater),the brachiumandthatfemalesoftendifferstronglyfrommales.
oases are characterized by the assemblage of species Villalobos (1982) proposed that the best identification
representingbiogeographicrelictsofsubtropicalmesophilic characteristics are the shape of the rostrum and the chelae
communities surrounded by the typical vegetation of the of the male’s second pair of pereiopods.
Sonoran Desert (Grismer, 1994). The vegetation and fauna, The presence of freshwater shrimp in the Baja California
such as arachnids, amphibians, reptiles, birds, and mam- Peninsulawasfirstannotatedin1780bytheJesuitpriestDel
mals,havebeenstudiedinrepresentativeoases(Arriagaand Barco (Leo´n-Portilla, 1988). However, the first formal
Rodr´ıguez-Estrella,1997).However,freshwatercrustaceans record was given by Lockington (1878), who reported
like the palemonid river shrimp have received little Macrobrachiumtenellum(Smith,1871)(citedasPalaemon
attention. longipes) from the oasis of Mulege´. From the same oasis
Palaemonids are among the most abundant and diverse Bouvier (1895) also reported M. americanum Bate, 1868
shrimpthat inhabit seawater andfreshwater inboth tropical (citedasPalemonjamaicensis)andM.tenellum(citedasP.
and temperate waters (Wicksten, 1983). The genus Macro- forceps) and described a new species, M. digueti (Bouvier,
brachium is well known because of the number of species, 1895) (cited as Palaemon digueti). Holthuis (1952),
351
352 JOURNALOFCRUSTACEANBIOLOGY,VOL.27,NO.2,2007
Rodr´ıguez De La Cruz (1968), R´ıos (1989), Wicksten and
Hendrickx(1992, 2003),andHendrickx(1994),listed from
the Baja California Peninsula the three species already
recorded by Bouvier (1895).
Wemadeataxonomicstudythatincludedanextensivefield
samplingonboththePacificandtheGulfofCaliforniaslopes
and a revision of voucher specimens from the area that had
beendepositedinscientificcollections.Inthisworkwereport
sixspeciesofthegenusMacrobrachiumforthepeninsulaand
discuss some aspects on the diversity and conservation of
thesespeciesintheregion.Wealsoprovideanidentification
keyforMacrobrachiumofnorthwesternMe´xico.
MATERIALSAND METHODS
Sampling
Shrimpwerecapturedusingdifferentfishinggear(handnet,castingnet,gill
net,andminnowtrapsbaitedwithfishmeat).Inmostofthesamplingsites,
water characteristics such as temperature, total dissolved solids (TDS)
(Hachmodel44600),andpH(ORION230A)weremeasuredatthetimeof
sampling. Thegeographicpositionof eachsamplingsite wasdetermined
using a GPS (Garmin 12XL). The specimens collected were placed in
plasticbags,anaesthesizedwithice,andfixedwith100%ethanol.
StudyArea
TheBajaCaliforniaPeninsulawasseparatedfromthemainlandbytectonic
movementsbetweenthePacificandtheNorthAmericanplatesalongthe
SanAndreasfault,withthegradualseparationoccurringoverthelast4to5
million years (Stock and Hodges, 1989). Today the northern part of the
peninsulaisdominatedbyhighgraniticmountains(SierraJua´rezandSierra
SanPedroMa´rtir)andthecentralregionischaracterizedbyrepeatinglayers
of volcano-clastic sandstones and conglomerates (Sierra de La Giganta).
Graniticrocksandhigherelevations(SierradeLaLaguna)appearagainin
thesouthernCaperegion(DurhamandAllison,1960).TheBajaCalifornia
Peninsula has a heterogeneous array of landscape and vegetation, from
coniferous and tropical deciduous forest in the mountains to xeric desert
scrubinlowaridplains(Riddleetal.,2000).Onthewesternsideofthe
peninsulathetopographicaltitudedecreasesgraduallyfromthemountains
tothecoasttoextensivesedimentaryalluvialplains,whereasontheeastern
sidethedistancefromthemountaintothecoastisshorter,oftenwithabrupt
escarpments(Grismer,2002).Becauseofitshistoricgeologywithcomplex
tectonicmovementsincludingupliftsandsubmergences,plustheecological
transformations produced by the geographic isolation and desertification,
thepeninsulanowhasapeculiarenvironmentaldiversitywiththeclimate
being characterized by relatively high annual mean temperatures (19 to
228C)andalowannualrainfall(100to300mm)(Grismer,2002).
Atotalof81sitesweresampled(seeAppendix)with71inthestateofBaja
CaliforniaSur(Fig.1)anddistributedalong20basinsandfourhydrological
regions.TheremainingsevensitesareinthestateofBajaCaliforniaand
distributedalongfourbasinsandtwohydrologicalregions.
IdentificationofMaterial
Anatomical nomenclature used in this work is according to McLaughlin
(1980).Additionaltermsaredefinedasfollows(Fig.2):
Fixedfinger:Nonjointedprojectionofthepropodus(manusorpalm)ofthe
cheliped.
Gapingfingers:Cuttingedgesoffixedfingeranddactylusarearched,thus
thereisaclearspacebetweenthem.
Closedfingers:Cuttingedgesoffixedfingeranddactylusarestraight,thus
thereisnoaclearspacebetweenthem.
Spine:A stout,sharpprocess,foundmostlyonthecarapace,pereiopods,
chelae,andtelson.
Spinules:Slendersmallspines,foundmostlyonthepereiopodsandchelae.
Tubercle:Smallroundedprominence,foundmostlyonthepereiopodsand
chelae.
Fig. 1. Distribution of Macrobrachium species in the state of Baja Pubescence:Smallandnumerousseta-likestructures.
California Sur, Me´xico (Southern Baja California Peninsula). Macro-
brachium americanum (triangle), M. digueti (eight tip-star), M. hobbsi ‹
(square),M.michoacanus(fivetip-star),M.olfersii(invertedtriangle),and sampling sites with no shrimp found. The thick line indicates the
M. tenellum (rhombus). Black dots indicate approximate locations of separationofthePacificandGulfofCaliforniaslopes.
HERNA´NDEZETAL.:MACROBRACHIUMFROMBAJACALIFORNIA,ME´XICO 353
Fig.2. SchematicrepresentationoftheappendagewiththelargestchelaofthesecondpairofpereiopodsofthegenusMacrobrachiumshowingthemain
structuresusefulforspeciesidentification(modifiedfromVillalobosandNates,1990).
Teeth: As described by McLaughlin (1980), but also as conspicuous andnumberofmalesandfemaleswithtotallengthmeasurements(whenthe
protuberances found sometimes along the cutting edge of one or both specimen was complete). For comparative purposes, specimens of three
fingersofthechela. Macrobrachium species not found in the Baja California Peninsula were
Denticles:Smallteethfoundalongthecuttingedgeofoneorbothfingersof alsoexaminedandincludedinthesectionsoftheirgeminatedspecies.
thechela.
Chelaeunequal:Rightandleftchelaaredifferentinsizeand-orinshape. SYSTEMATICS
Chelaesubequal:Rightandleftchelaaresimilarinsizeandshape.
Palaemonidae Rafinesque, 1815
Macrobrachium Bate, 1868
Inthelaboratory,thematerialwassortedaccordingtogender.Maleswere
Macrobrachium americanum Bate, 1868
distinguished by the presence of the appendix masculina on the
(Fig. 3)
secondpleopods.Thefollowingmeasurementswereobtained:totallength
(TL)(fromtipofrostrumtoposteriorendoftelson)andlengthofmerus, Macrobrachium americanum Bate, 1868; Holthuis, 1952; Rodr´ıguez De
carpus,palm(lengthandheight),anddactylusofthelargerchelaofthesecond La Cruz, 1968; Wicksten, 1983, 1989; R´ıos, 1989; Wicksten and
pairofpereiopods.Thenumberofteethonbothmarginsoftherostrumwas Hendrickx,1992,2003;Villalobos-Hiriartetal.,1993;Hendrickx,
recorded.Adatabasewithallmorphometricandmeristicdatawasdeposited 1994.
in the Crustacea collection at Centro de Investigaciones Biolo´gicas del PalemonjamaicensisHerbst;Bouvier,1895.
Noroeste,S.C.,LaPaz,BajaCaliforniaSur,Me´xico(CIB).Specimenswere
Type Locality.—Lago Amatitla´n, Guatemala.
identified using the keys for the species of Macrobrachium proposed by
Holthuis(1952)andWicksten(1989)andtheoriginaldescriptionsofthe
Diagnosis.—Rostrum strong, arched over orbital margin,
species.AllcollectedmaterialwasdepositedintheCrustaceacollectionat
CIB. The material of Macrobrachium was also revised in the scientific curved upward at tip; it reaches the end joint of antennular
collections at Universidad Nacional Auto´noma de Me´xico, Coleccio´n peduncle;dorsalmarginwith10to12teethofwhichthreeto
Nacional de Crusta´ceos; Instituto de Biolog´ıa, Me´xico City (CNCR); four are placed behind orbital margin; ventral margin with
Coleccio´n de Crusta´ceos, Instituto de Ciencias del Mar y Limnolog´ıa,
two to four teeth. Second pair of pereiopods with subequal
Mazatla´n(EMU);UniversidadAuto´nomadeBajaCalifornia,Facultadde
Ciencias,Coleccio´ndeCrusta´ceos(UABC);andthecrustaceancollectionof chelae and gaping fingers; carpus almost twice as long as
theMuse´umNationald’HistoireNaturelle,Paris(MNHN). high and shorter than merus. Whole chela covered with
spinules.Palmelongated,fingersslightlyshorterthanpalm.
PresentationoftheTaxonomicAccount Fingers with single strong tooth on cutting edge; tooth of
The taxonomic account includes: 1) species name, author, and year of fixedfingeronfirstthirdofcuttingedge,dactyluswithtooth
description;2)synonymy,restrictedtonamesusedforMexicanspecimens inthemiddle;twotofourproximaldenticlesonbothfingers.
(for a complete synonymy see Holthuis, 1952); 3) type locality; 4)
diagnosis;5)distributionintheBajaCaliforniaPeninsula,includingdataon Distribution in the Baja California Peninsula.—This
water characteristics and on the co-occurrence of the species with other
common species was previously reported from Mulege´,
congenericforms;6)distributioninMe´xico(followinganorth-southorder);
La Paz, and Cabo San Lucas (Bouvier, 1895; Holthuis,
7)generaldistribution;8)remarks;and9)materialexamined,indicatingthe
country,state, site,collectiondate,seniorcollector’sname,catalogcode, 1952). We found it on the Pacific slope in the basins
354 JOURNALOFCRUSTACEANBIOLOGY,VOL.27,NO.2,2007
Fig.3. AdultmalesofMacrobrachiumamericanumBate,1868.A,Rostruminrightlateralview;B,Anteriorregionindorsalview;C,Largestchelaofthe
secondpairofpereiopodsininnerview.AllfiguresfromCIB814.Scalebars¼10mm.
Santa Rita, Las Pocitas, Todos Santos, and Plutarco El´ıas 1.5 g/L, pH 6.7 to 8.3, and temperatures 23.9 to
Calles, and on the Gulf of California slope in the basins 34.58C. Macrobrachium americanum was found often
of Mulege´, El Coyote, San Bartolo, and San Jose´ del co-ocurring with the other five species found in the
Cabo. Specimens were found in waters with TDS 0.34 to peninsula. An assemblage of four species (M. americanum,
HERNA´NDEZETAL.:MACROBRACHIUMFROMBAJACALIFORNIA,ME´XICO 355
M. digueti, M. hobbsi, and M. michoacanus) was recorded However Chirichigno etal. (1982) only mentioned that this
at the Los Potreros site. species may be located in the fishery zone 77A, which
comprises an enormous area from Baja California to
Distribution in Me´xico.—BAJA CALIFORNIA SUR (see
Oaxaca, but did not give any particular data from Isla
above). SONORA: Guaymas (Holthuis, 1952), R´ıo Yaqui,
Cedros. Records of this species from Mexican islands are
and R´ıo Mayo (Rodr´ıguez De La Cruz, 1968). SINALOA:
those from Isla Mar´ıa Magdalena and Isla Mar´ıa Cleofas,
El Rosario, R´ıo El Fuerte, R´ıo Presidio, R´ıo Quelite
Nayarit (Holthuis, 1952; Herna´ndez and Mart´ınez, 1992).
(Holthuis, 1952; Rodr´ıguez De La Cruz, 1968; Hendrickx,
1994), and Mazatla´n. NAYARIT: Isla Mar´ıa Magdalena, Material Examined.—Macrobrachium americanum: ME´X-
and Isla Mar´ıa Cleofas (Holthuis, 1952; Herna´ndez and ICO:BAJACALIFORNIASUR:Mulege´ dam,28.02.2004,
Mart´ınez, 1992), R´ıo Santiago, and Jalcocota´n. JALISCO: A.Maeda,CIB803,1female;Guadalupedam,C.Me´ndez,
R´ıo Santiago, and R´ıo Ameca (Holthuis, 1952), Chamela, CIB 860, 2 specimens; Las Paredes, 30.05.2004, L.
Cuitzmala, and Puerto Vallarta. COLIMA: R´ıo Armer´ıa Herna´ndez, CIB 804, 1 male (139.5 mm); San Juanito
(Holthuis, 1952). MICHOACA´N: La Villita, and Mexcalti- Nuevo, 22.09.2004, L. Herna´ndez, CIB 866, 1 specimen;
tla´n.GUERRERO:Bah´ıaPetatla´n(Holthuis,1952),andR´ıo Rancho Tres Pozas, 30.05.2004, L. Herna´ndez, CIB 805, 2
Murga. OAXACA: Pochutla, Salina Cruz, R´ıo Valdeflores, males(134and246mm);Merecuaco,16.05.1998,G.Ruiz-
Tuxtepec, Mixtequita dam, and Tehuantepec. CHIAPAS: Campos, UABC 003, 1 male (115 mm); Corral de Piedra,
Mal Paso dam, and R´ıo El Naranjo. 29.05.04, L. Herna´ndez, CIB 806, 1 male (121.3 mm); El
Caracol,29.05.2004,L.Herna´ndez,CIB807,1male(151.1
General Distribution.—Baja California Peninsula to Peru´,
mm) and 1 female (151 mm); Poza de La Matanza,
Cocos Island, and Gala´pagos Islands (Holthuis, 1952;
29.05.2004, L. Herna´ndez, CIB 808, 1 male (152 mm);
Wicksten and Hendrickx, 1992, 2003).
Santa Fe, 26.02.2004, L. Herna´ndez, CIB 867, 1 specimen;
Remarks.—Similar to Macrobrachium carcinus (Linnaeus, Las Vinoramas, 21.11.2003, A. Maeda, CIB 809, 1 female
1758), M. americanum is one of the largest species of the (59.2mm);LasVinoramas,03.12.2003,L.Herna´ndez,CIB
genus and its size may help to distinguish it from other 810,2males(63and69.8mm);TodosSantos,26.02.2004,
species(Holthuis, 1952). Thelargestspecimen inourstudy L. Herna´ndez, CIB 811, 1 male (145 mm); La Poza,
was found at Rancho Tres Pozas (Santa Rita basin) at 246- 10.07.2005, L. Mercier, CIB 861; 1 specimen; Agua
mmTL.SmallspecimensmaybeconfusedwithmalesofM. Caliente, 13.12.2003, A. Maeda, CIB 812, 1 female (70
occidentale or M. heterochirus (Wiegmann, 1836), but M. mm);RanchoSanAntonio,08.09.2004,L.Herna´ndez,CIB
americanumcanbedistinguishedbyitssubequalchelae,the 813, 1 female (129.4 mm); Los Potreros, 06.10.2002, A.
form and size of the carpus, and by the rostral length. The Maeda, CIB 814, 1 female (144.5 mm, ovigerous); Los
Atlantic geminated species of M. americanum is the big Potreros 24.07.2003, L. Herna´ndez, CIB 815, 2 females
claw river shrimp M. carcinus (Holthuis, 1952) that has (109.6 and 112 mm, ovigerous); Poza de Santa Rosa,
been reported from the Florida to Brazil (Bowles et al., 14.12.2003, A. Maeda, CIB 816, 2 females (131.7 and 68
2000). Differences among specimens is not easy to detect, mm);SanJose´ delCaboestuary,26.11.2004,L.Herna´ndez,
however Holthuis (1952) noted that M. carcinus is sligthly CIB862,1specimen.SINALOA:Mazatla´n,10.09.1973,D.
larger than M. americanum and that the carpus length is Pela´ez, CNCR 199, 1 specimen; EMU 0268, 3 specimens.
more than twice as long as high in M. carcinus, whereas in NAYARIT: R´ıo Santiago, 07.07.1991, C. Rosales, CNCR
M. americanum the same characteristic is not more than 11499, 1 specimen; Jalcocota´n, 13.09.2003, L. Herna´ndez,
twice as long as high. In our revision of 86 voucher CIB 853, 5 males (104 to 185.5 mm), 1 female (118 mm),
specimens, we noted that proportions on the carpus as and 1 ovigerous female (132.9 mm). JALISCO: Puerto
previously established by Holthuis are consistent, so this Vallarta, 17.09.1973, A. Jime´nez, CNCR 202, 1 specimen;
characteristicmayhelpustoseparatebothspecies.Colorin Chamela, 31.08.1992,CNCR1619,1 specimen. COLIMA:
life for M. carcinus is dark brown with lighter mottling on R´ıo Armer´ıa, 12.09.1973, CNCR 200, 2 specimens.
the sides and tan stripes laterally. Chelipeds are dark green MICHOACA´N: La Villita, 28.09.1973, A. Villalobos,
tobluewithdarktuberclesandorangearticulations(Bowles CNCR 205, 2 specimens; La Villita, CNCR 13685, 1 male
et al., 2000). In M. americanum the body is yellow-brown (190 mm). GUERRERO: R´ıo Murga, 08.05.1984, A.
withtanstripeslaterallyfromthecarapacetotelsonandthe Villalobos, CNCR 2624, 5 juveniles; R´ıo Murga,
periopodswithbluearticulations.Inadults,thefingersofthe 21.05.1984; A. Villalobos, CNCR 2663, 3 specimens; R´ıo
secondpairofchelipedsaredarkwithsomelittlespecimens Murga,23.09.1986;J.C.Nates,CNCR3116,2males(118.4
showing the terminal third of the fingers in white. and 95 mm), 1 female (ovigerous). OAXACA: R´ıo
After the Holthuis (1952) review, there was only one Valdeflores,24.05.1961,A.Villalobos,CNCR198,1spec-
recordofM.americanumforthepeninsulareportedbyR´ıos imen; Salina Cruz, 11.09.1973, I. Larios, CNCR 201, 1
(1989), who found it at Mulege´. The new records from the specimen;Tuxtepec,13.09.1973,A.Villalobos,CNCR204,
Pacific slope basins such as Santa Rita, Las Pocitas, Los 4 specimens; Mixtequita dam, 21.12.1955, A. Villalobos,
Potreros, and Todos Santos extend the geographical CNCR 208, 2 specimens. CHIAPAS: Mal Paso dam,
distribution of the species to the west side of the peninsula. 12.09.1973, C. Beutelspacher, CNCR 203, 4 specimens;
The collections from the Santa Rita basin represent its R´ıoElNaranjo, 06.09.2002,E.Soto,CNCR22021,1male
northernmost records in the Pacific slope. A´lvarez-Ruiz (69.8 mm). Macrobrachium carcinus: ME´XICO: MNHN
et al. (1996) cited Chirichigno et al. (1982) as reporting 1222, 1 specimen (172 mm); MNHN 989, 1 specimen;
M. americanum from Isla Cedros, Baja California, Me´xico. CNCR 13332, 2 males (118.4 and 140.1 mm); CNCR
356 JOURNALOFCRUSTACEANBIOLOGY,VOL.27,NO.2,2007
Fig.4. AdultmalesofMacrobrachiumdigueti(Bouvier,1895).A,Rostruminleftlateralview;B,Anteriorregionindorsalview;C-D,Largestchelaofthe
secondpairofpereiopodsinlateralview.AandCfromCIB801,BfromCIB817,DfromMNHN1235,andEfromBouvier(1895).Scalebars¼10mm.
13667, 2 females (133.9 and 141.4 mm); CNCR 13676, 1 Macrobrachium digueti (Bouvier, 1895)
female(143.9mm);CNCR16494,1male(61mm);CNCR (Fig. 4)
17174, 1 female (110.6 mm); CNCR 17380, 2 females PalaemondiguetiBouvier,1895.
(151.3 and 159.4 mm); CNCR 17401, 1 male (228.5 mm); Macrobrachium digueti (Bouvier, 1895); Holthuis, 1952; Rodr´ıguez De
La Cruz, 1968; Wicksten, 1983, 1989; R´ıos, 1989; Wicksten and
CNCR 17403, 1 male (216.3 mm); CNCR 18648, 3 males
Hendrickx,1992,2003;Villalobos-Hiriartetal.,1993;Hendrickx,
(125.7 to 206.2 mm) and 1 male (174.5 mm). 1994;Roma´netal.,2000.
HERNA´NDEZETAL.:MACROBRACHIUMFROMBAJACALIFORNIA,ME´XICO 357
Macrobrachium acanthochirus Villalobos, 1967; Villalobos, 1968; Villa- doigts be´ants, enfin on n’observe pas de longs poils
lobosandNates,1990;Wicksten,1989;WickstenandHendrickx, duveteux sur la face externe de cette pince et le e´pines de
1992,2003;Villalobos-Hiriartetal.,1993;Roma´netal.,2000.
la face interne sont moins nombreuses que dans le P.
spinimanus et plus irre´gulie`rement dispose´es’’ (its second
Type Locality.—Mulege´, Baja California Sur. large chela is shorter, higher, and completely without large
setae between the fingers, finally we do not observe large
Diagnosis.—Rostrum straight, reaching last joint of anten-
setaeovertheexternalfaceofthechelaandthespinesofthe
nularpeduncle;dorsalmarginwith13to16teeth,fourtosix
internal face are less numerous than in P. spinimanus and
placed behind orbital margin; ventral margin with three to
more irregularly disposed). According to Holthuis (1952),
five teeth. Second pair of pereiopods with unequal chelae
Palemon spinimanus is a synonym of Macrobrachium
and gaping fingers; carpus and merus globose at middle
faustinum(DeSassure,1857).L.Herna´ndezinParisrevised
section. Largest chela with palm almost as long as high,
a lot (MNHN 1235) labeled as Syntype of P. Digueti,
with spines on dorsal margin and external side. Palm with
Mulege´, 1895. This lot contained 16 specimens (39.5 to
scarce pubescence, without setae. Fixed finger with up to
56.4 mm), most of them incomplete. One incomplete
four teeth on proximal half of cutting edge. Dactylus with
appendage still having carpus, propodus, and dactylus
a stout tooth, and up to four denticles on proximal part of
seems to correspond to that described and figured by
cutting edge.
Bouvier (1895) (Fig. 4E). Bouvier’s measurements were
Distribution in the Baja California Peninsula.—Macro- -longueur de la pince 38 mm; largeur maximum 16 mm;
brachium digueti, previously collected from Mulege´, La longueur de doigt mobile 22 mm- (length of the chela
Paz, and Cabo San Lucas (Bouvier, 1895; Holthuis, 1952; 38 mm, maximum height 16 mm; length of the mobile
Hendrickx,1994),wasfoundonlyattwosites,oneinBoca finger 22 mm). The chela examined by L. Herna´ndez had
de la Sierra, Santiago basin in the Gulf of California slope similarvalueswithacarpuslengthof12.7mm,palmlength
andtheotherinLosPotreros,PlutarcoEl´ıasCallesbasinon 20.1 mm, and dactylus length 20.3 mm. The remaining 16
thePacificslope.SpecimenswerefoundinwaterswithTDS specimens were determined by L. Herna´ndez as Macro-
0.18 to 1.5 g/L, pH 7.8 to 8.8, and temperature 25.3 to brachium hobbsi Nates and Villalobos, 1990.
33.78C. We found this species co-occurring with three Macrobrachium acanthochirus Villalobos, 1967 was
congeners at Los Potreros. Previously, Bouvier (1895) described from two lots, one from specimens collected in
reported this species along with M. americanum and M. Tecoma´n, Colima and the other from R´ıo Valdeflores,
tenellum. Oaxaca.Villalobos(1968)wasnotsureaboutthevalidityof
this species, even proposing that it could be better assigned
Distribution in Me´xico.—BAJA CALIFORNIA SUR
as a subspecies of M. digueti. Upon the morphological
(see above). SONORA: R´ıo Yaqui and R´ıo Mayo
examination of 28 voucher specimens (see below the
(Rodr´ıguez De La Cruz, 1968). SINALOA: Laguna
material examined), the similar proportion values of the
Caimanero and R´ıo Baluarte (Wicksten and Hendrickx,
carpus length/palm length, and palm length/palm high
2003). NAYARIT: Colomo´. JALISCO: Cuitzmala and R´ıo
shown by specimens of both nominal taxa (Table 1), the
Los Cuartones. COLIMA: Tecoma´n, and Puerto Jua´rez.
overlap distribution of both forms along the Pacific slope,
MICHOACA´N: Mexcaltitla´n, R´ıo Murga, and La Villita.
we concur that M. acanthochirus should remain as
GUERRERO: Acapulco (Wicksten and Hendrickx, 2003).
a synonym of M. digueti.
OAXACA: Valdeflores.
Macrobrachium digueti is similar to M. olfersii (Wieg-
mann, 1836), however in M. digueti there isno pubescence
General Distribution.—Baja California Peninsula to Peru´
but scarce setae on the second large chela, whereas in M.
(Holthuis,1952; Wicksten and Hendrickx, 1992, 2003).
olfersii the chela characteristically has copious setae and
Remarks.—Villalobos (1968) indicated that the description pubescence. Though M. digueti has only a few teeth on the
ofthisspeciesgivenbyHolthuis(1952)doesnotcorrespond proximalpartofthecuttingedgeofbothfingers,M.olfersii
totheoriginalspeciesofBouvier(1895)andweagreewith hasmorethanfiveteethalongthecuttingedgeofbothfingers.
this assessment. Holthuis (1952, plate 26) described the Macrobrachium digueti is rare in the Baja California
largest second chela of Macrobrachium digueti as ‘‘The Peninsula. We found no specimens at the type locality, the
second legs are very unequal in shape and size in the adult oasis of Mulege´. R´ıos (1989) did not find any specimens at
male.Thefingersinthelargerchelaareaslongasthepalm; Mulege´ during four years of monitoring. This suggests that
they arecurved andgape.The cutting edges ofboth fingers the species has been extirped from the type locality. Our
bear in the extreme proximal part one large tooth, behind collection at Los Potreros represents the first record of the
which 1 or 2 much smaller teeth are placed. The cutting speciesonthePacificslopeoftheBajaCaliforniaPeninsula.
edgedistallyofthelargeteethisprovidedwithteeth9to12
in number, which are placed up to the tips of the fingers. Material Examined.—Macrobrachium digueti: ME´XICO:
Tuftsofhairareimplantedalongthecuttingedges.Therest BAJA CALIFORNIA SUR: Mulege´, 1894, L. Diguet,
ofthefingersisnakedandisdenselycoveredwithspinules. MNHN 1235, 1 second largest chela of a male (Syntype);
Thepalmhasadistinct,largethicklypubescentareaateach Mulege´, CNCR 10619, 4 specimens; Boca de la Sierra,
ofthelateralsurfaces’’.Thesefeaturesdonotcorrespondto 08.09.2004, L. Herna´ndez, CIB 801, 2 males (78.6 and
those of the original description given by Bouvier (1895), 70 mm); Los Potreros, 06.10.2002, A. Maeda, CIB 802, 1
who wrote ‘‘sa grande pince est plus courte, plus large et male (79.4 mm); Los Potreros, 06.10.2002, A. Maeda, CIB
comple`tement de´pourvue de longues soies raides entre les 817,1female(81.3mm);SanJose´ delCabo,19.09.1946,I.
358 JOURNALOFCRUSTACEANBIOLOGY,VOL.27,NO.2,2007
Table1. MorphometricdataofthelargestchelaofthesecondpairofperiopodsandrostralteethofMacrobrachiumdiguetimalesfromseveralMexican
locations.CaL,carpuslength;PL,palmlength;PH,palmhigh;DL,dactyluslength;CL,carapacelength(allinmm).
Specimen CaL PL CaL/PL PH PL/PH DL Rostralteeth CL Reference
HolotypefromMulege´,BajaCaliforniaSur — — — 16 — 22 14-16 28 Bouvier,1895
SyntypefromMulege´,BajaCaliforniaSur(MNHN1235) 12.7 20.1 0.63 16.2 1.2 20.3 — — thisstudy
MalefromTecoma´n,Colima(citedasM.acanthochirus) 11.4 14 0.81 13.2 1.06 16.5 13(5)/4 28.9 Villalobos,1967
MalefromTecoma´n,Colima(CNCR328,labeledas
holotypeofM.acanthochirus) 10.4 15.7 0.66 13.3 1.18 16.7 13(5)/4 20 thisstudy
MalefromValdeflores,Oaxaca(citedasM.acanthochirus) 10.3 14.5 0.71 12 1.2 15 — 27 Villalobos,1967
MalefromLosPotreros,BajaCaliforniaSur(CIB802) 10.3 12.6 0.79 10.1 1.24 13.4 15(4)/3 27.3 thisstudy
MalefromColomo´,Nayarit(CIB866) 14.1 20.6 0.68 18.9 1.08 23.7 14(6)/4 29 thisstudy
MalefromR´ıoMurga,Guerrero(CNCR3538,labeledas
M.acanthochirus) 10.7 18.1 0.59 17.2 1.08 19.9 14(5)/5 24.4 thisstudy
Bonet, CNCR 235, 1 male (77 mm); San Jose´ del Cabo, Distribution in Me´xico.—Endemic to Me´xico from Guer-
10.09.1946,F.Bonet,CNCR236,3specimens.SINALOA: rero to Chiapas and Veracruz (Villalobos and Nates, 1990;
R´ıo Baluarte, EMU 0840, 3 females (62 to 74 mm). Wicksten and Hendrickx,2003) andfrom thewest andeast
NAYARIT: Colomo´, 13.08.2003 L. Herna´ndez, CIB 866, sidesoftheBajaCaliforniaPeninsula,andinNayarit.BAJA
5 specimens (75 to 91 mm). JALISCO: Cuitzmala, CALIFORNIA SUR (see above). NAYARIT: R´ıo Huayna-
04.02.1983, J.C. Nates, CNCR 2723, 1 male (65.1 mm, mota and Los Salazares. GUERRERO: R´ıo Murga (Villa-
labeled as M. acanthochirus); Cuizmala, 20.02.1984, J.C. lobos and Nates, 1990). OAXACA: R´ıo Astuta (Villalobos
Nates, CNCR 3121, 9 specimens (40 to 87 mm); R´ıo Los and Nates, 1990). CHIAPAS: R´ıo Lagartero, Arroyo
Cuartones, 01.03.1992, A. Novelo, 1 male, CNCR 13372 Ocuilapa, R´ıo Cintalapa, R´ıo Chacamax (Villalobos and
(labeled as M. acanthochirus). COLIMA: Tecoma´n, Nates, 1990), R´ıo Grande, and R´ıo Urbina. VERACRUZ:
18.01.1943,F.Bonet,CNCR328,1male(62mm)(labeled R´ıo La Palma (Villalobos and Nates, 1990).
as holotype of Macrobrachium acanthochirus Villalobos,
Remarks.—Large specimens of Macrobrachium hobbsi
1967); Puerto Jua´rez, 23.06.1986, R. Navarro, 1 female,
may be confused with M. olfersii (Wiegmann, 1836). One
CNCR 20804 (labeled as M. acanthochirus). MICHOA-
CA´N: Mexcaltitla´n, 31.07.1984, J.C. Nates, 12 males, important difference between the two species noted by
Villalobos and Nates (1990) is the absence of space in the
CNCR 3536 (labeled as M. acanthochirus); R´ıo Murga,
cutting edges of both fingers of the second largest chela in
28.07.1984, CNCR 3538 (labeled as Macrobrachium sp.);
M. hobbsi. The second pair of chelae are subequal in shape
La Villita, 15.12.1994, CNCR 12986, 2 specimens.
butnotinsize,whereasinM.olfersiithesecondlargechelae
GUERRERO: Acapulco, 13.08.1973, W. Lo´pez, CNCR
are unequal.
141, 1 male (59 mm, labeled as M. acanthochirus);
Macrobrachiumhobbsiisanamphiamericanspecieswith
OAXACA: Valdeflores, 25.05.1962, A. Villalobos, CNCR
331, 2 specimens (labeled as M. acanthochirus). a wide distribution in Baja California Sur and occurs on
boththePacificandGulfofCaliforniaslopes.OjodeAgua
in the La Pur´ısima basin is the northernmost site of the
Macrobrachium hobbsi Nates and Villalobos, 1990
speciesdistribution.Thereisanapparentdistributiongapof
(Fig. 5)
the species between the Baja California Peninsula and the
MacrobrachiumhobbsiNatesandVillalobos,1990;VillalobosandNates,
R´ıo Huaynamota, Nayarit.
1990; Villalobos-Hiriart et al., 1993; Wicksten and Hendrickx,
2003. Material Examined.—Macrobrachium hobbsi: ME´XICO:
Type Locality.—R´ıo El Naranjo, Chiapas. BAJA CALIFORNIA SUR: Mulege´, 1895, MNHN 1235,
16 specimens (39.5 to 56.4 mm) (labeled as M. Digueti);
Diagnosis.—Rostrum straight, reaching last joint of anten-
Ojo de Agua, 01.07.2004, G. Ruiz-Campos, UABC 009, 4
nularpeduncle;dorsalmarginwith13to16teeth,fourtosix
males (59 to 68 mm) and 9 females (69 to 91 mm); Ojo de
placed behind orbital margin; ventral margin with two to
Agua,14.07.2004,L.Herna´ndez,CIB818,3males(64.4to
four teeth. Second pair of pereiopods with unequal chelae
79.3 mm) and 1 ovigerous female (61.5 mm); San Isidro
and closed fingers. Carpus shorter than palm length,
dam, 15.07.2004, L. Herna´ndez, CIB 819, 5 males (49.3 to
subequal to merus length. Palm with spinules covered with
69.8 mm) and 4 specimens; La Pur´ısima, 01.07.2004, G.
pubescence. Palm about two times or more long as high.
Ruiz-Campos,UABC008,10specimens(56.2to73.2mm);
Adult specimens of the species are small (, 100 mm).
La Pur´ısima, 02.07.2004, G. Ruiz-Campos, UABC 006, 3
DistributionintheBajaCaliforniaPeninsula.—Firstrecords males (72.5 to 77.2 mm); San Juanico road, 14.07.2004, L.
of the species in the peninsula. It was collected on the Herna´ndez, CIB 820, 1 male (53 mm); San Pedro de la
Pacific slope at La Pur´ısima, Santa Rita, Las Pocitas, and Presa,30.05.2004, L.Herna´ndez,CIB821,3females (53.5
Plutarco El´ıas Calles basins, and on the Gulf of California to 68.4 mm) and 8 specimens; San Basilio, 30.05.2004, L.
slope in the basin of Mulege´. Specimens were found in Herna´ndez, CIB 822, 3 males (47 to 72.8 mm) and 9
waters with TDS 0.29 to 1.09 g/L, pH 6.7 to 8.9, and specimens; Las Paredes, 30.05.2004, L. Herna´ndez, CIB
temperatures 22.1 to 32.58C. We found this species co- 823,8males(46.2to56mm)and51specimensofjuveniles
ocurring with the other five species found in the peninsula. and females; Merecuaco, 16.05.1998, G. Ruiz-Campos,
HERNA´NDEZETAL.:MACROBRACHIUMFROMBAJACALIFORNIA,ME´XICO 359
UABC 002, 7 specimens (43.6 to 69.2 mm); Paso Iritu´, L.
Herna´ndez, CIB 824, 3 males (42.1 to 52.1 mm); El
Caracol,29.05.2004,L.Herna´ndez,CIB825,3males(50to
63.2mmTL),and7specimens;ElColorado,02.03.2004,L.
Herna´ndez, CIB 826, 1 male (67.2 mm and 6 females; Los
Potreros, 06.10.2002, A. Maeda, CIB 827, 7 males, and 2
females (52.3 and 63.6 mm); San Pedro de la Soledad,
25.11.2004, L. Herna´ndez, CIB 828, 1 female. NAYARIT:
R´ıo Huaynamota, 03.07.1991, A. Cantu´, CNCR 13357, 1
male (69.2 mm); Los Salazares, 14.08.2003, L. Herna´ndez,
CIB 854, 2 males (65.2 and 66.8 mm) and 4 ovigerous
females. CHIAPAS: R´ıo Grande, 14.02.1985, J.L. Villalo-
bos, CNCR 5605, 3 males (68.9 to 79.7 mm); R´ıo Urbina,
10.06.2002,CNCR13335,1female(54.3mm);ElNaranjo,
J.C. Nates, CNCR 2939 (Holotype), 1 male (67.5 mm).
Macrobrachium michoacanus
Nates and Villalobos, 1990
(Fig. 6)
MacrobrachiummichoacanusNatesandVillalobos,1990;Villalobosand
Nates, 1990; Villalobos-Hiriart et al., 1993; Wicksten and
Hendrickx,2003.
Type Locality.—R´ıo Mexcalhuaca´n, Michoaca´n.
Diagnosis.—Rostrum straight, reaching last joint of anten-
nularpeduncle;dorsalmarginwith14to15teeth,fivetosix
behindorbitalmargin;ventralmarginwiththreetofourteeth.
Second pair of pereiopods with unequal chelae and closed
fingers.Merusabout1.5timeslongerthancarpus.Palmwith
spines distributed on lateral surface, scarce pubescence on
lateralventralarea,andlessthantwotimesaslongashigh.
DistributionintheBajaCaliforniaPeninsula.—Firstrecords
of the species for the peninsula. Macrobrachium michoa-
canus was collected on the Pacific slope in Las Pocitas and
Plutarco El´ıas Calles basins. Specimens were found in
waters with TDS 0.71 to 3.56 g/L, pH 7.4 to 9.3, and
temperatures 22.1 to 31.38C. This species was co-occurring
with the other five congeneric species.
Distribution in Me´xico.—Endemic to Me´xico, from Jalisco
to Oaxaca (Villalobos and Nates, 1990; Wicksten and
Hendrickx, 2003). Also found on the west side of the Baja
California Peninsula. BAJA CALIFORNIA SUR (see
above). JALISCO: R´ıo Cuitzmala (Villalobos and Nates,
1990), Chamela, and R´ıo Las Aletas. MICHOACA´N:
Morelos dam, R´ıo Chucatitla´n, and R´ıo Papoyutla (Villa-
lobos and Nates, 1990). GUERRERO: R´ıo Murga, R´ıo
Aguas Blancas, Mexcalhuaca´n (Villalobos and Nates,
1990), R´ıo Salitrera, and La Villita. OAXACA: R´ıo
Valdeflores (Villalobos and Nates, 1990; Wicksten and
Hendrickx, 2003), and R´ıo Galva´n.
Fig. 5. Adult males of Macrobrachium hobbsi Nates and Villalobos,
Remarks.—This species is similar to M. digueti, but it can 1990.A,Rostruminleftlateralview;B,Anteriorregionindorsalview;C,
be distinguished by the shape of the cutting edges of the Largestchelaofthesecondpairofpereiopodsinlateralview.AandBfrom
fingerofthesecondmayorchelaasnotedbyVillalobosand CIB824,andCfromCIB828.Scalebars¼10mm.
Nates (1990). Macrobrachium michoacanus has closed
fingers on the second large chela, whereas M. digueti has the second species has spinules and pubescence on the
gaping fingers. The differences between M. michoacanus palm and the palm length is at least two times longer
and the other species with closed fingers, M. hobbsi, are than high.
in the palm. The first species has spines on the palm and LasCuevasinLasPocitasbasinofthePacificslopeofthe
the length of the palm is less than twice the high, whereas BajaCaliforniaPeninsulaisthenorthernmostboundaryofthe
360 JOURNALOFCRUSTACEANBIOLOGY,VOL.27,NO.2,2007
MaterialExamined.—Macrobrachiummichoacanus:ME´X-
ICO: BAJA CALIFORNIA SUR: San Basilio, 15.05.1998,
G. Ruiz-Campos, UABC 001, 5 males (51.5 to 75.2 mm)
and 2 females; Rancho Las Cuevas, 30.05.2004, L.
Herna´ndez, CIB 829, 2 males (57.9 and 74.2 mm); Paso
Iritu´, 16.05.1998, G. Ruiz-Campos, UABC 004, 9 males
(39.7 to 70.3 mm) and 13 females (34 to 65 mm); El
Cardalito, 19.11.2003, A. Maeda, CIB 830, 1 ovigerous
female (59.4 mm); Los Potreros, 24.07.2003, A. Maeda,
CIB 831, 1 male (45.6 mm) and 2 other males. JALISCO:
Chamela, 25.07.1998, C. Sa´nchez, CNCR 191, 2 speci-
mens; Chamela, 19.06.1991, C. Sa´nchez, CNCR 192, 3
specimens; Chamela 12.09.1991, G. Casas, CNCR 196, 1
specimen; Puerto Vallarta, Las Aletas stream, 17.09.1973,
A. Jime´nez, CNCR 195, 1 specimen. GUERRERO: La
Villita,28.09.1973,A.Villalobos,CNCR209,3specimens;
Mexcalhuaca´n,31.06.1984,J.C.Nates,CNCR3550,1male
(56mm)(Holotype);R´ıoSalitrera,Zihuatanejo,22.07.1987,
J.P.Gallo,CNCR13292,1male(17.1mm)and1ovigerous
female. OAXACA: R´ıo Galva´n, 31.05.1995, J.P. Gallo,
CNCR 13293, 1 male (84.7 mm).
Macrobrachium olfersii
(Wiegmann, 1836)
(Fig. 7)
PalaemonolfersiiWiegmann,1836.
Macrobrachium olfersii (Wiegmann, 1836); Hedgpeth, 1949; Villalobos,
1968; Villalobos-Hiriart et al., 1993; Herna´ndez-Aguilera et al.,
1996;WickstenandHendrickx,2003.
Macrobrachium olfersi (Wiegmann, 1836); Holthuis, 1952; Villalobos,
1968.
Type Locality.—Not assigned. The original material was
reported from a Brazilian shore.
Diagnosis.—Rostrum straight, reaching third joint of
antennular peduncle; dorsal margin with 12 to 16 teeth,
three to six placed behind orbital margin; ventral margin
with one to five teeth. Second pair of pereiopods with
unequalchelaeandgapingfingers;carpusshorterthanpalm
lengthandaboutaslongasthemerus;palmabout1.5times
long as high, with setae and pubescence on the lateral side;
dactylus length slightly shorter than palm length; cutting
edges of fingers with numerous denticles and dense hairs.
Distribution in the Baja California Peninsula.—Our collec-
tions represent the first records of the species for the
peninsula. Macrobrachium olfersii is the second amphia-
merican species recorded in the peninsula. It was found
mainly on the Pacific slope in the basins of La Pur´ısima,
SantoDomingo,SantaRita,LasPocitas,TodosSantos,and
Plutarco El´ıas Calles. On the Gulf of California slope the
Fig. 6. Adult males of Macrobrachium michoacanus Nates and species was found only in the Alfredo V. Bonfil and San
Villalobos 1990. A, Rostrum in left lateral view; B, Anterior region in
Jose´ delCabobasins.Specimenswerefoundinwaterswith
dorsal view; C, Largest chela of the second pair of pereiopods in lateral
TDS0.26to0.61g/L,pH8.1to8.4,andtemperatures19.1
view.AfromCIB829,andBandCfromCIB831.Scalebars¼10mm.
to 34.88C. This species was co-occurring with other four
congeners.
speciesdistribution.ThespecieswasnotfoundalongtheGulf Distribution in Me´xico.—BAJA CALIFORNIA SUR (see
ofCaliforniaslope.Thereisanapparentgapinthedistribu- above).SINALOA:R´ıoBaluarte(WickstenandHendrickx,
tion of the species between the Baja California Peninsula 2003).NAYARIT:LosSalazares,R´ıoSantiago,andArroyo
andthenorthernmostrecordatR´ıoCuitzmala,Jalisco. Bogadero. MICHOACA´N: Mexcaltita´n, and San Nicola´s