phylogenetic relationships and classification of didelphid marsupials ...

More documents

Recommendations

Info

168 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 322 Character 112: Cutting edge of unworn i3 not bilobed (0); or distinctly bilobed (1). See text for a discussion of this character and its taxonomic distribution. This character was scored as missing (‘‘?’’) for caenolestids, for which lower incisor homologies are unknown. Character 113: Fourth lower incisor (i4) present (0); or absent (1). See text for a discussion of this character and its taxonomic distribution. This character was scored as missing (‘‘?’’) for caenolestids, for which lower incisor homologies are unknown. Character 114: Second lower premolar distinctly taller than p3 (0); or p2 and p3 subequal in height (1); or p3 distinctly taller than p2 (2). Scoring criteria and information about the distribution and ordering (0 « 1 « 2) of these traits among didelphid terminals were provided by Voss and Jansa (2003: character 63). See text for comments about traits expressed by outgroup taxa. Character 115: Deciduous lower third premolar (dp3) large and occlusally functional, with tricuspid (complete) trigonid (0); or dp3 smaller but still occlusally functional, with unicuspid or bicuspid (incomplete) trigonid (1); or dp3 vestigial, usually lacking distinct occlusal features (2). See text for a discussion of this character and its taxonomic distribution. In the absence of juvenile specimens, this character was scored as missing (‘‘?’’) for several taxa. Because state 1 is plausibly intermediate to states 0 and 2, we treated this character as ordered (0 « 1 « 2) in all of our analyses. Character 116: Hypoconulid notch in anterior cingulum of m2–m4 present (0); or absent (1). See text for a discussion of this character and its taxonomic distribution. Character 117: Paracristid of m1 deeply notched (0); or unnotched (1). See text for a discussion of this character and its taxonomic distribution. Character 118: Paracristid of m2 extends from protoconid to paraconid without deflection (0); or m2 paracristid abruptly deflected posterolingually by hypoconulid of m1 (1). See text for a discussion of this character and its taxonomic distribution. Character 119: Trigonid of m4 complete (0); or only metaconid distinct on m4 trigonid (1). See text for a discussion of this character and its taxonomic distribution. Character 120: Lower third molar hypoconid labially salient (0); or m3 hypoconid lingual to salient protoconid (1). Scoring criteria and information about the distribution of these traits among didelphid terminals were provided by Voss and Jansa (2003: character 65). Caenolestids, Dromiciops, and peramelid outgroups have salient hypoconids, but the hypoconid is lingual to the protoconid in Murexia and Sminthopsis. Character 121: Entoconid large and well developed on m1–m3 (0); or very small or indistinct (1). Scoring criteria and information about the distribution of these traits among didelphid terminals were provided by Voss and Jansa (2003: character 66). All examined ougroup taxa exhibit state 0. Character 122: Entocristid absent or indistinct (0); or present (1). A distinct entocristid is present in all examined taxa except Sminthopsis and Perameles. Character 123: Entocristid a short crest parallel to lingual margin of tooth (0); or entocristid long and labially deflected into talonid basin (1). See text for a discussion of this character and its taxonomic distribution. This character was coded as inapplicable (‘‘-’’) in taxa lacking an entocristid (above). Character 124: Hypoconulid at or near posterolingual margin of talonid, ‘‘twinned’’ with entoconid on m1– m3 (0); or at midline of tooth, approximately equidistant to hypoconid and entoconid, not ‘‘twinned’’ with the latter cusp (1). Scoring criteria and information about the distribution of these traits among didelphid terminals were provided by Voss and Jansa (2003: character 67). All examined ougroup taxa exhibit state 0. Character 125: Lower molars without a posterior cingulid (0); or posterior cingulid present (1). See text for a discussion of this character and its taxonomic distribution. KARYOTYPES Character 126: Robertsonian equivalents {acr1 + acr5, met1} present as a single metacentric chromosome (0); or as two acrocentric chromosomes (1). Most marsupials, including all of the outgroups in this analysis, have a diploid number (2n) of 14 chromosomes (Sharman, 1973; Hayman, 1977, 1990; Reig et al., 1977), and this is also the most widespread number among didelphids (table 18). By contrast, Glironia and Monodelphis have diploid counts of 18 chromosomes, whereas Chironectes, Didelphis, Lutreolina, Philander, and Tlacuatzin have 2n 5 22. Morphometric comparisons and G-banding studies indicate that each of these diploid groupings are homogeneous in the sense that different taxa with the same diploid number have chromosomes with essentially similar relative sizes, shapes (arm ratios), and banding patterns (Reig et al., 1977; Rofe and Hayman, 1985; Svartman and Vianna-Morgante, 1999). By implication, a shared history of Robertsonian changes (centric fissions or centric fusions) could account for the taxonomic membership of each diploid category. A minimum of four centric fission/fusion events is required to account for the difference in diploid number between karyotypes with 14 chromosomes and those with 22 chromosomes. Based on arm homologies suggested by G-banding patterns, the following Robertsonian transformations involving eight acrocentric (acr) autosomes in the 2n 5 22 karyotype and four metacentric (met) autosomes in the 2n 5 14 karyotype are indicated (chromosomes are numbered from small to large within each karyotype): acr1 + acr5 « met1, acr2 + acr8 « met2, acr3 + acr10 « met3, and acr6 + acr9 « met4 (Svartman and Vianna-Morgante, 1999). The 2n 5 18 karyotype is intermediate because it has only two metacentric autosomes, of which the larger can be homologized with acr2 + acr8 of the 2n 5 22 karyotype and with met2 of the 2n 5 14
2009 VOSS AND JANSA: DIDELPHID MARSUPIALS 169 Taxon 2n a karyotype, whereas the smaller metacentric can be homologized with acr6 + acr9 of the 2n 5 22 karyotype and with met4 of the 2n 5 14 karyotype (op. cit.). As explained by Voss and Jansa (2003: 42–44; see also Dobigny et al., 2004), these transformational homologies are appropriately coded as separate characters, one for each set of Robertsonian equivalents—for example, {acr2 + TABLE 18 Exemplar Didelphid Karyotypes References Caluromys lanatus 14 Reig et al. (1977), Palma and Yates (1996), Patton et al. (2000) Caluromys philander 14 Reig et al. (1977) Chironectes minimus 22 Reig et al. (1977), Palma and Yates (1996) Cryptonanus chacoensis b 14 Wainberg et al. (1979) Didelphis albiventris 22 Reig et al. (1977), Palma and Yates (1996) Didelphis marsupialis 22 Gardner (1973), Reig et al. (1977), Palma and Yates (1996), Patton et al. (2000) Didelphis virginiana 22 Gardner (1973), Reig et al. (1977) Glironia venusta 18 Fantin and da Silva (in press) Gracilinanus agilis 14 Carvalho et al. (2002) Gracilinanus microtarsus 14 Wainberg et al. (1979), Carvalho et al. (2002) Lestodelphys halli 14 Birney et al. (1996) Lutreolina crassicaudata 22 Reig et al. (1977), Palma and Yates (1996) Marmosa (Micoureus) demerarae c 14 Reig et al. (1977), Palma and Yates (1996), Patton et al (2000) Marmosa (Marmosa) mexicana 14 Biggers et al. (1965) Marmosa (Marmosa) murina 14 Reig et al. (1977) Marmosa (Micoureus) paraguayana d 14 Carvalho et al. (2002) Marmosa (Micoureus) regina 14 Patton et al. (2000) Marmosa (Marmosa) robinsoni 14 Reig et al. (1977) Marmosops impavidus 14 Patton et al. (2000) Marmosops incanus 14 Carvalho et al. (2002) Marmosops noctivagus 14 Palma and Yates (1996), Patton et al. (2000) Metachirus nudicaudatus 14 Reig et al. (1977), Palma and Yates (1996), Patton et al. (2000) Monodelphis brevicaudata e 18 Carvalho et al. (2002) Monodelphis emiliae 18 Patton et al. (2000) Philander frenatus 22 Carvalho et al. (2002) Philander mcilhennyi 22 Reig et al. (1977), Patton et al. (2000) Philander opossum 22 Reig et al. (1977) Thylamys macrurus 14 Palma (1995) Thylamys pallidior 14 Palma and Yates (1996) Thylamys pusillus 14 Palma and Yates (1998) Thylamys venustus f 14 Palma and Yates (1996) Tlacuatzin canescens 22 Engstrom and Gardner (1988) a Diploid number. b Identified as ‘‘Marmosa agilis chacoensis’’ by Wainberg et al. (1979). c Identified as ‘‘Marmosa cinerea’’ by Reig et al. (1977), and as ‘‘Micoureus cinereus’’ by Palma and Yates (1996). d The specimens of ‘‘Micoureus demerarae’’ that Carvalho et al. (2002) karyotyped from Rio Grande do Sul are referable to this taxon. e Some karyotyped specimens previously identified in the literature as Monodelphis brevicaudata (sensu lato) may represent other species. Based on known geographic ranges (Voss et al., 2001), the Venezuelan karyotypes described by Reig et al. (1977) were probably obtained from M. palliolata, whereas the Bolivian karyotypes described by Palma and Yates (1996) were probably obtained from M. glirina. f Karyotyped Bolivian material identified as Thylamys elegans by Palma and Yates (1996) was reidentified as T. venustus by Palma and Yates (1998). acr8, met2}—which can exist in two states: fused (metacentric) or fissioned (acrocentric). Character 127: Robertsonian equivalents {acr2 + acr8, met2} present as a single metacentric chromosome (0); or as two acrocentric chromosomes (1). Character 128: Robertsonian equivalents {acr3 + acr10, met3} present as a single metacentric chromosome (0); or as two acrocentric chromosomes (1).
Page 1 and 2:
PHYLOGENETIC RELATIONSHIPS AND CLAS
Page 3 and 4:
CONTENTS Abstract .................
Page 5 and 6:
ABSTRACT This report summarizes a d
Page 7 and 8:
2009 VOSS AND JANSA: DIDELPHID MARS
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118: 2009 VOSS AND JANSA: DIDELPHID MARS
Page 167: 2009 VOSS AND JANSA: DIDELPHID MARS
Page 177: 2009 VOSS AND JANSA: DIDELPHID MARS
show all

phylogenetic relationships and classification of didelphid marsupials ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?