Gayana 73(2): 180 - 199, 2009 ISSN 0717-652X DIVERSITY AND DISTRIBUTION OF THE MOUSE OPOSSUMS OF THE GENUS THYLAMYS (DIDELPHIMORPHIA, DIDELPHIDAE) IN NORTH- EASTERN AND CENTRAL ARGENTINA DIVERSIDAD Y DISTRIBUCION DE LAS MARMOSAS DEL GENERO THYLAMYS (DIDELPHIMORPHIA, DIDELPHIDAE) EN EL NORESTE Y CENTRO DE ARGENTINA Pablo Teta1**XLOOHUPR'¶(OtD2, David Flores1 1RpGH/D6DQFKD3 1 Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Avenida Angel Gallardo 470 (C1405DJR) Buenos $LUHV$UJHQWLQD 2 'HSDUWDPHQWRGH=RRORJtD8QLYHUVLGDGGH&RQFHSFLyQFDVLOOD&&RQFHSFLyQ&KLOH 3 'HSDUWPHQWRI%LRORJLFDO6FLHQFHV7H[DV7HFK8QLYHUVLW\32%R[/XEERFN7H[DV86$ E-mail: DQWKHFD#\DKRRFRPDr ABSTRACT Phylogenetic analysis of a fragment of the mitochondrial genome and qualitative and quantitative assessments of morphological variation suggest that, in its current conception, Thylamys pusillus 'HVPDUHVW LVDFRPSOH[RIDW OHDVWWKUHHVSHFLHV,QWKHWD[RQRPLFDUUDQJHPHQWSURSRVHGLQWKLVZRUNWKHSRSXODWLRQVLQWKH$UJHQWLQHDQSURYLQFHV of Entre Ríos and Corrientes are here referred to T citellus (Thomas, 1912), while the small Thylamys that lives in the Argentinean Dry Chaco are provisionally referred to Tpulchellus &DEUHUD ,QRXUVFKHPHThylamys pusillus is UHVWULFWHGWRWKH%ROLYLDQDQG3DUDJXD\DQ&KDFRDQGWKHYLFLQLWLHVRIQRUWKHUQ)RUPRVDSURYLQFHLQ$UJHQWLQD:HSURYLGH emended diagnosis for T citellus and Tpulchellus, together with detailed morphological descriptions and discuss their distinctiveness from other species of Thylamys,QDGGLWLRQZHLQFOXGHGQHZGLVWULEXWLRQDOGDWD KEYWORDS$UJHQWLQDPRXVHRSRVVXPVSHFLHVOLPLWVWD[RQRP\ RESUMEN (ODQiOLVLV¿ORJHQpWLFRGHXQIUDJPHQWRGHOJHQRPD\HOHVWXGLRFXDOLWDWLYR\FXDQWLWDWLYRGHODPRUIRORJtDH[WHUQD\ craneana sugiere que, en su actual acepción, Thylamys pusillus (Desmarest, 1804) es un complejo de por lo menos tres HVSHFLHV(QHODUUHJORWD[RQyPLFRSURSXHVWRHQHVWHWUDEDMRODVSREODFLRQHVHQODVSURYLQFLDVDUJHQWLQDVGH(QWUH5tRV y Corrientes son referidas como T citellus (Thomas, 1912), mientras que una forma pequeña de Thylamys que habita en el Chaco Seco de Argentina es provisoriamente referida como Tpulchellus &DEUHUD (QHVWHHVTXHPDOD distribución de Thylamys pusillus es restringida al Chaco de Bolivia, Paraguay y áreas adyacentes de Argentina en el QRUGHVWHGHODSURYLQFLDGH)RUPRVD6HSURYHHQGLDJQRVLVHQPHQGDGDVSDUDT citellus y Tpulchellus, conjuntamente con una detallada descripción morfológica de ambas entidades y una discusión de las diferencias con otras especies de Thylamys3RUXOWLPRVHLQFOX\HQQXHYRVGDWRVGHGLVWULEXFLyQ PALABRAS CLAVE:$UJHQWLQDPDUPRVDVOtPLWHGHHVSHFLHVWD[RQRPtD 180 7D[RQRP\RIThylamys: TETA,P.ET AL. INTRODUCTION al. 2005a, Flores et al.&UHLJKWRQ *DUGQHU 2008) restrict the name pusillus to the central and The genus Thylamys Gray 1843 comprises small northeastern populations from Argentina, western mouse opossums with some distinctive traits, 3DUDJXD\DQGHDVWHUQ%ROLYLD8QGHUWKLVFRQFHSWLRQ including a characteristic tricolor fur pattern, T. pusillus includes, as subjective junior synonyms, capacity to store fat in the tail, uniformly narrow WKHQRPLQDOWD[DMarmosa citella 7KRPDV nasals with subparallel lateral margins, large Marmosa janetta pulchella &DEUHUDDQG SRVWHURODWHUDOSDODWDOIRUDPLQDH[WHQGLQJDQWHULRUO\ Marmosa verax7KRPDV VHH&UHLJKWRQ between M4 protocones, and other morphological *DUGQHU 3DUWRIWKHFRQIXVLRQUHJDUGLQJ characters in body proportions, skull, dentition, and the biological and geographic limits of T. pusillus SRVWFUDQLXP &UHLJWKRQ *UDGQHU)ORUHV GHULYHVIURPWKHDEVHQFHRIDW\SHVSHFLPHQ,Q 9RVV -DQVD 8QOLNHPRVWRWKHU6RXWK fact, the name pusillus was proposed on the basis of American mouse opossums, which are found in $]DUD¶VGHVFULSWLRQRIWKH³PLFRXUpQDLQ´RU³HQDQR´ tropical or subtropical moist forests, Thylamys (Azara, 1801, 1802), without the formal designation principally inhabits semi-arid and open areas and RIDW\SHVSHFLPHQ*LYHQWKLV9RVVet al. (in press) occurs at temperate latitudes (Flores et al. 2007, designed a neotype for pusillus from Trans-Chaco &UHLJKWRQ *DUGQHU +LJKZD\NP1:RI9LOOD+D\HV 'HSDUWDPHQWR ThylamysKDVEHHQXQGHUWD[RQRPLFUHYLVLRQ %RTXHUyQ3DUDJXD\ ,QWKHVDPHFRQWULEXWLRQWKH since Tate (1933) recognized the elegans species authors suggest that some Argentinean populations group as part of the genus Marmosa6XEVHTXHQW of pusillus-like Thylamys may represent a different systematic works, based on morphological, species than the nominotypical form that occurs VHURORJLFDODQGFKURPRVRPDOHYLGHQFHFRQ¿UPHG LQ3DUDJXD\DQGHDVWHUQ%ROLYLD2QWKHRWKHU the distinctiveness of Thylamys within the didelphid hand, Argentinean populations from Entre Ríos radiation (Reig et al.*DUGQHU &UHLJKWRQ and Corrientes provinces (Mesopotamia), usually 1989, Palma et al. 3K\ORJHQHWLFVWXGLHV synonymyzed in the literature with pusillus, have EDVHGRQJHQHWLFGDWDFRQ¿UPHGWKHPRQRSK\O\ DORQJDQGFRPSOH[WD[RQRPLFKLVWRU\EHLQJ of the genus, and elucidated some basic questions alternatively included in Marmosa marmota, regarding relationships among its species and their Thylamys pusillus, or considered a separated species OLPLWV .LUVFK 3DOPD-DQVD 9RVV under the name of M. citella 7KRPDV 3DOPD <DWHV)ORUHVet al. 2000, Meynard et ,QWKLVZRUNZHSUHVHQWDWD[RQRPLFDQDO\VLVRI al. 2002, Palma et al. 2002, Braun et al.D Argentinean populations of Thylamys that are As currently recognized, Thylamys comprises at currently included within T. pusillus7KHPDLQ OHDVWQLQHVSHFLHV &UHLJKWRQ *DUGQHU goal of this study is to clarify how many species with modifications according to Braun et al LQKDELWWKHDUHD7RGRVRZHDQDO\]HGPRUSKRORJLF D ,QQRUWKHUQ$UJHQWLQDWKLVLVWKHPRVW DQGJHQHWLFHYLGHQFH,QOLJKWRIRXUUHVXOWVZH diverse marsupial genus, and one of the groups provide emended diagnosis, re-descriptions, and ZLWKPRUHWD[RQRPLFXQFHUWDLQWLHV)RUPDQ\ comparisons for the species recognized in a new \HDUVWD[RQRPLVWVFRQVLGHUHGRQO\WKUHHVSHFLHVLQ WD[RQRPLFDUUDQJHPHQWKHUHLQSURSRVHG northern Argentina: T. pallidior, in arid highlands DQGPRQWDQHGHVHUWVTvenustus in montane humid DQGWUDQVLWLRQDOIRUHVWVDQG T. pusillus in the MATERIALS AND METHODS H[WHQVLYH[HURSK\WLFVKUXEVDQGJUDVVODQGVIURPWKH QRUWKDQGQRUWKHDVWHUQUHJLRQVRIWKHFRXQWU\ STUDY SPECIMENS. A total of 86 specimens from 7KHWD[RQRPLFVWDWXVRI Thylamys pusillus has $UJHQWLQDDQG3DUDJXD\ZHUHVWXGLHG )LJ ORQJEHHQFRQWURYHUVLDO)RULQVWDQFH7DWH $SSHQGL[ WKHVHZHUHDOUHDG\KRXVHGLQ restricted the name pusillus to populations in systematic collections, or were obtained by us QRUWKHDVWHUQ$UJHQWLQDDQGHDVWHUQ3DUDJXD\/DWHU either by trapping or from owl pellet analysis &DEUHUD H[SDQGHGpusillus to include forms $SSHQGL[ $QLPDOFDUHDQGXVHSURFHGXUHV from the Andean highlands and southern steppes and guidelines approved by the American Society previously assigned to pallidiorE\7DWH of Mammalogists were followed (Gannon et al 5HFHQWFRQWULEXWLRQV HJ6RODUL%UDXQ et )RUFRPSDUDWLYHSXUSRVHVZHVWXGLHGVHULHV 181 Gayana 73(2), 2009 FIGURE 1. Recording localities for the specimens of Thylamys citellus (circles), T. pulchellus (triangles), and T. pusillus VTXDUHV UHYLVHGLQWKLVZRUN QXPEHUVFRUUHVSRQGVWRWKRVHRIWKH$SSHQGL[ DQGDGGLWLRQDOORFDOLWLHVIRUThylamys pulchellus (from Braun et al. $UJHQWLQD&DWDPDUFD&DSD\iQ&KXPELFKDNP(RI+LJKZD\DORQJ 6: 6DQ-XDQ&DXFHWH4XHEUDGDGH/DV)ORUHVNP(DQGNP1*XD\DPDV FD 6:6DQWLDJRGHO(VWHUR$OEHUGLNP6NP(3DPSDGH/RV*XDQDFRV 6: &KR\D6DOLQDVGH$PEDUJDVWDDSSNP6(&HUUR5LFR 6: DQG Tpusillus3DUDJXD\%RTXHUyQ7UDQV&KDFR+LJKZD\NP1:9LOOD+D\HV 6: W\SHORFDOLW\¿[HGE\QHRW\SHVHOHFWLRQ>9RVVet al.LQSUHVV@ FIGURA 1/RFDOLGDGHVGHUHJLVWURSDUDORVHMHPSODUHVGHThylamys citellus (círculos), T. pulchellus (triángulos) y T. pusillus FXDGUDGRV UHYLVDGRVHQHVWHWUDEDMR ORVQ~PHURVFRUUHVSRQGHQDORVDQRWDGRVHQHO$SpQGLFH \ORFDOLGDGHV adicionales para Thylamys pulchellus (tomadas de Braun et al. $UJHQWLQD&DWDPDUFD&DSD\iQ&KXPELFKD NP(RI+LJKZD\DORQJ 6: 6DQ-XDQ&DXFHWH4XHEUDGDGH/DV)ORUHV NP(DQGNP1*XD\DPDV FD6:6DQWLDJRGHO(VWHUR$OEHUGLNP6NP( 3DPSDGH/RV*XDQDFRV 6: &KR\D6DOLQDVGH$PEDUJDVWDDSSNP6(&HUUR5LFR 6: \Tpusillus3DUDJXD\%RTXHUyQ7UDQV&KDFR+LJKZD\NP1:9LOOD +D\HV :ORFDOLGDGWLSR¿MDGDSRUVHOHFFLyQGHQHRWLSR>9RVVet al.HQSUHQVD@ of Thylamys pallidior VHH$SSHQGL[ DQGXVHG -DQVD 6WDQGDUGH[WHUQDOPHDVXUHVIRU diagnostic traits annotated in the literature for T mammals were recorded from field catalogs or macrurus (Voss et alLQSUHVV VSHFLPHQWDJV+%KHDGDQGERG\OHQJWK7/WDLO length, HF: hind foot length (including the claw), and MORPHOLOGIC DATA ANALYSIS1RPHQFODWXUHXVHGWR (/HDUOHQJWK(LJKWVNXOODQGGHQWDOPHDVXUHPHQWV describe the skull and its structures follows Voss were recorded following Voss et al. D WKHVH 182 7D[RQRP\RIThylamys: TETA,P.ET AL. TABLE I.'HVFULSWLYHVWDWLVWLFVIRUH[WHUQDODQGFUDQLDOYDULDEOHVRIDGXOWPDOHVDQGIHPDOHV DJHFODVVHVDQG RI Thylamys citellus, T. pulchellus, and T. pusillus6HHPDWHULDOVDQGPHWKRGVIRUWKHH[SODQDWLRQRIWKHDEEUHYLDWXUHV6G VWDQGDUGGHYLDWLRQ TABLA I.(VWDGtVWLFRVGHVFULSWLYRVSDUDYDULDEOHVH[WHUQDV\FUDQHDQDVGHHMHPSODUHVDGXOWRVPDFKRV\KHPEUDV FODVHV de edad 6 y 7) de Thylamys citellus, Tpulchellus y Tpusillus9pDVHPDWHULDOHV\PpWRGRVSDUDXQDH[SOLFDFLyQGHODV DEUHYLDWXUDV6G GHVYLDFLyQHVWiQGDU MI- HB T HF EL CBL ZB LIB PL PB MTR LM M3 Thylamys Mean citellus Minimum 0D[LPXP Sd N 555555555555 Thylamys Mean pulchellus Minimum 0D[LPXP Sd N 1111911999999109 Thylamys Mean pusillus Minimum 0D[LPXP 6,5 Sd N 383838365759616262624862 are: condylobasal length (CBL), palatal length (PL), species of ThylamysZHUHDQDO\]HG 7DEOH,, 2XU least interorbital breadth (LIB), palatal breadth (PB), sampling lacks sequences representing