phylogenetic relationships and classification of didelphid marsupials ...

2009 VOSS AND JANSA: DIDELPHID MARSUPIALS 83
mark catalog of the marsupials in the British
Museum of Natural History.
By comparison with Old World marsupials,
didelphids appeared to Thomas (1888:
315) to be ‘‘an exceedingly homogeneous
[family], its members presenting a very small
range of differentiation.’’ Accordingly, he
recognized only Didelphis and Chironectes as
full genera, but several other taxa were ranked
as subgenera of Didelphis (table 16). These
included Metachirus (containing species now
referred to Metachirus, Philander, and Lutreolina),
Philander (for Caluromys), Micoureus
(containing species now referred to
Marmosa, Marmosops, Thylamys, andGracilinanus),
and Peramys (for Monodelphis).
Although knowledge of didelphid diversity
increased rapidly in the years following
Thomas’s classification, Matschie (1916) persisted
in referring all nonaquatic opossums to
the genus Didelphis. However, Matschie
recognized more subgenera of Didelphis than
Thomas did, resurrecting old names or
describing new ones to suit his needs.
Dromiciops (described as a didelphid by
TABLE 16
Classifications of Recent Opossums, 1888–1958 a
Thomas (1888) Matschie (1916) Cabrera (1919) Simpson (1945) Cabrera (1958)
Didelphidae Didelphidae Didelphidae Didelphidae Didelphidae
Didelphis Didelphis Dromiciops Philander Caluromys
Didelphis b
Didelphis b
Glironia Monodelphis Caluromysiops
Metachirus b
Metachirops b
Philander Dromiciops Glironia
Philander b
Metachirus b
Marmosa Glironia Dromiciops
Micoureus b
Peramys b
Marmosa b
Notodelphis c
Monodelphis
Peramys b
Micoureus b
Thylamys b
Marmosa Monodelphis b
Chironectes Caluromys b
Peramys Metachirops Minuania b
Marmosa b
Minuania Metachirus Lestodelphys
Grymaeomys b
Lutreolina Lutreolina Marmosa
Marmosops b
Metachirus Didelphis Marmosa b
Thylamys b
Holothylax Chironectes Thylamys b
Dromiciops b
Didelphis Philander
Glironia b
Chironectes Metachirus
Monodelphis b
Lutreolina
Monodelphiops b
Didelphis
Microdelphys b
[Chironectes]
Chironectes
a
Incorrect spellings (e.g., ‘‘Didelphys’’ for Didelphis; Thomas, 1888) have been changed to conform with current usage
throughout, but the sequence of names in each classification has been preserved as originally published. Note that some
names (e.g., Philander) were used by early taxonomists for species that are now placed in other genera (see text).
b
Ranked as subgenera.
c
Not an available name. Notodelphys Thomas, 1921, originally proposed for the taxon now known as Lestodelphys,is
preoccupied by Notodelphys Allman, 1847, a copepod (Tate, 1934).
Thomas, 1894) was also included. Matschie’s
taxonomy is noteworthy for his early recognition
that the so-called ‘‘murine’’ opossums
(pouchless mouse- and rat-sized species with
circumocular masks and long tails) that
Thomas (1888) had lumped together in
Micoureus actually represent several distinct
groups, and for treating those groups as
coordinate taxa.
Cabrera’s (1919) classification was not the
first to reject Linnaeus’s inclusive concept of
Didelphis, but it was influential in establishing
modern binomial usage. His taxonomy
included 11 genera, only one of which
contained subgenera. Like Thomas (1888)
and Matschie (1916), Cabrera made no use of
subfamilies, tribes, or other suprageneric
categories to indicate relationships among
living opossums. Unlike Matschie, Cabrera
grouped all of the ‘‘murine’’ opossums
together, using Marmosa as the name for
the taxon that Thomas called Micoureus.
Simpson (1945) recognized several subfamilies
of didelphids, but he placed all of the
living opossums (plus Dromiciops) in the