Species Limits And Phylogenetic Relationships In The Didelphid Marsupial Genus Thylamys Based On Mitochondrial Dna Sequences And Morphology Author Giarla, T. C. Author Voss, R. S. Author Jansa, S. A. text Bulletin of the American Museum of Natural History 2010 2010-12-16 2010 346 1 67 journal article 0003-0090 Xerodelphys , new subgenus a See text for trait definitions. TYPE SPECIES: Thylamys karimii . CONTENTS: Thylamys karimii and T. velutinus . b Number of specimens scored for this character. c Only tissue vouchers scored. TABLE 14 Nominal Species-group Taxa Referred to Thylamys , Type Specimens, and Type Localities a
Type specimen Type locality
bruchi Thomas, 1921 BMNH 21.4.21.8b Argentina: San Luis, Alto Pencoso
cinderella Thomas, 1902 BMNH 0.7.9.20 b Argentina: ‘‘Tucuman’’
citellus Thomas, 1912 BMNH 98.8.19.9b Argentina: Corrientes, Goya
coquimbensis Tate, 1931 FMNH 23302 b Chile: Coquimbo, Paiguano
elegans Waterhouse, 1839 BMNH 53.8.29.18c Chile: ‘‘Valparaiso’’
fenestrae Marelli, 1932 MACN 14955d Argentina: Buenos Aires, Tornquist,
Abra de la Ventana
griseus Desmarest, 1827 UMMZ 125243e Paraguay: Amambay, 28 km SW Pedro
Juan Caballero
janetta Thomas, 1926 BMNH 26.1.1.167b Bolivia: Tarija, Carlazo
karimii Petter, 1968 MNHN 1968-148 b Brazil: Pernambuco, Exu
macrurus Olfers, 1818 UMMZ 125243e Paraguay: Amambay, 28 km SW Pedro
Juan Caballero
nanus Olfers, 1818 MVZ 144311e Paraguay: Boquerón, 460 km NW Villa
Hayes
pallidior Thomas, 1902 BMNH 2.2.2.116 b Bolivia: Oruro, Challapata
pimelura Reinhardt, 1851 ZMUC 164f Brazil: Minas Gerais, Lagoa Santa
pulchellus Cabrera, 1934 MLP 21-X-35-32b Argentina: Santiago del Estero, Robles
pusillus Desmarest, 1804 MVZ 144311e Paraguay: Boquerón, 460 km NW Villa
Hayes
soricinus Philippi, 1894 unknown g Chile: ‘‘Valdivia’’
sponsorius Thomas, 1921 BMNH 21.1.1.85b Argentina: Jujuy, Sunchal
tatei Handley, 1957 USNM 302915b Peru: Ancash, Chasquitambo
velutinus Wagner, 1842 NMW B-2621h Brazil: São Paulo, Ipanema
(‘‘Ypanema’’)
venustus Thomas, 1902 BMNH 2.1.1.120b Bolivia: Cochabamba, Parotani
(‘‘Paratani’’)
verax Thomas, 1921 BMNH 20.12.18.34b Paraguay: Presidente Hayes, Misión
Central i
a Only available names are listed. Names of species recognized as valid in this report are in boldface. The gender of epithets originally published in combination with feminine generic names ( Didelphis and Marmosa ) has been changed to agree with Thylamys (masculine). Full bibliographic information for all names is provided in Gardner (2008) . b Holotype by original designation. c The specimen currently recognized as the type (e.g., by Tate, 1933 ; Jenkins and Knutson, 1983 ) is one of several—all collected by Darwin at Valdivia—that Waterhouse (1839) may have examined. Of these putative syntypes, Thomas (1888: 354) selected one (specimen ‘‘e’’ in his list) as the ‘‘type’’ (lectotype according to the Code; ICZN, 1999 : Article 4). Handwritten annotations in Thomas’s personal copy of his catalog identify specimen ‘‘e’’ as BMNH 53.8.29.18 (P. Jenkins, personal commun.). d Neotype ( Martin, 2009 ). e Neotype (Voss et al., 2009). f Lectotype ( Tate, 1933: 234 ). g Based on a mounted specimen formerly preserved in the Museo Nacional de Historia Natural in Santiago, Chile ( Osgood, 1943 ). Possibly still extant, but catalog number and preservation unknown. h Holotype by monotypy ( Pelzeln, 1883: 115). i Verbatim type locality is ‘‘Mision, west of Concepcion’’ in the ‘‘Northern Chaco of Paraguay’’ ( Thomas, 1921: 521 ). DIAGNOSIS: Members of the subgenus Xerodelphys can be distinguished from other congeners (herein referred to the nominotypical subgenus, see below) by their reduction or loss of plantar dermatoglyphs, lack of a concave central palmar surface, tails that are shorter than the combined length of head and body, and absence of distinct modifications for caudal prehension (table 15). REMARKS: Although the monophyly of Xerodelphys is only weakly supported by phylogenetic analyses of our concatenated- gene dataset ( fig. 11 ), the absence of a concave central palmar surface (resulting from fusion of plantar pads on the manus) and the reduction or loss of plantar dermatoglyphs are unique in the family Didelphidae and provide supporting evidence that these two species form a clade. Sequence data from nuclear loci will presumably allow future tests of this hypothesis. TABLE 15 Morphological Comparisons among Thylamys (Xerodelphys) karimii , T. (X.) velutinus , and Members of the Subgenus Thylamys
karimii velutinus Subgenus Thylamys a
Body pelage tricolored bicolored tricolored
Ventral fur self-white gray-based variable b
Manual claws long long variable b
Manual dermatoglyphs absent vestigial well-developed
Central palmar surface absent absent present
Tail , HBL , HBL $ HBL
Caudal prehensile surface vestigial vestigial well-developed
Nasolabial fossa shallow deeply excavated shallow
a Including Thylamys macrurus , T. pusillus , and members of the Elegans and Venustus groups. b Varies taxonomically (see table 16). The morphological distinctness of the taxa we refer to Xerodelphys was previously recognized by Solari (2003) , who, however, regarded karimii as a synonym of velutinus . Carmignotto and Monfort (2006) were the first to clearly identify the diagnostic traits that distinguish T. karimii and T. velutinus from each other and from congeneric species that we refer to the nominotypical subgenus, but they prudently refrained from naming a new genus-group taxon in the absence of a supporting phylogenetic analysis. We commend their restraint and credit them with the morphological observations on which our subgeneric diagnosis is based.