New and noteworthy records of Rodentia (Erethizontidae, Sciuridae, and Cricetidae) from Paraguay
Author
D’Elía, Guillermo
Author
Mora, Ismael
Author
Myers, Phil
Author
Owen, Robert D.
text
Zootaxa
2008
1784
39
57
journal article
10.5281/zenodo.182407
882b995c-8e5b-42a4-ac52-3dcf104ab6ac
1175-5326
182407
Oxymycterus misionalis
Sanborn
Fig. 5
.
Table 1
Type
Locality:
Río Paranay, Misiones,
Argentina
; restricted to the confluence of the Paranay Guazú and Paraná Rivers, General San Martín, Misiones by
Pardiñas et al. (2007)
.
Distribution
: Known from the Argentinean province of Misiones and from Alto Paraná in
Paraguay
.
New records:
ALTO PARANA: 6) Puerto Bertoni, 25º.38’ S 54º.40’ W,
91 m
(BMNH 21.4.21.4). CA- NINDEYU: 7) Colonia Britez Cue,
24º 15’ 05.2’’ S
55º 18’ 24.1’’ W
,
222 m
(TK
130587
); 8) Colonia Britez Cue,
24º 14’ 21’’ S
55º 16’ 04’’ W
,
266 m
(TK
121751
, TK
121752
, TK
141169
).
Figure 1
. The record from Alto Paraná was taken from the unpublished dissertation of Joäo A. Oliveira (1998).
Taxonomy:
In spite of recent advances (e.g. Oliveira 1998;
Hoffmann et al., 2002
), the alpha taxonomy of
Oxymycterus
remains confused in several aspects, and as explained below, difficult issues continue to arise. Our records may play a key role to solve a complex
Oxymycterus
nomenclatorial and taxonomic issue, as they approximate the probable collection locality of the
type
of
O
. rufus
(Fischer)
and by extension, the population which should be ascribed to this taxon. By their morphology, our specimens belong to the species presently bearing the name
O
. misionalis
, not to
O
. rufus
as it is currently understood (for a detailed revision of
Oxymycterus
see Oliveira 1998). However, they may in fact represent the latter taxon. Fischer (1814) named
Oxymycterus rufus
on the basis of Azara’s (1801) description of the “rat roux” (
Contreras & Teta 2003
). Azara based his description on a mouse sent to him by his friend Pedro Blas Noceda, a priest that practiced at the towns of Santiago, Santa María de Fe, and San Ignacio, in southern
Paraguay
. This convinced
Galliari
et al
. (1996)
to restrict the
type
locality of
O
. rufus
to San Ignacio in the Department of Misiones,
Paraguay
. By the same line of reasoning, more than 150 years earlier,
Rengger (1830)
restricted the
type
locality of
O
. rufus
to an area (Ñu Guazu) near Asunción, the Paraguayan capital. The view that the
type
locality of
O
. rufus
lies in
Paraguay
was followed, sometimes with simplifications, by later authors (e.g.,
Gyldenstolpe 1932
indicated only “
Paraguay
” as the
type
locality;
Cabrera 1961
). The actual place where Noceda collected the specimens, however, remains unknown. This uncertainty, in conjunction with two other issues, has led most authorities of sigmodontine taxonomy during the last two decades to consider the
terra typica
of
O
. rufus
to lie in
Argentina
rather than
Paraguay
(e.g.,
Hershkovitz 1994
, Oliveira 1998; Musser and Carleton 2005; but see
Contreras & Teta 2003
). The first of these issues is that a second specimen of
Oxymycterus
(“hocicudo”) described by
Azara (1802)
was incorrectly assumed to be the same individual that served as the diagnosis basis of the rat roux (see details in
Contreras & Teta 2003
). In his 1802 book, Azara provided latitudinal information (32 ½ degrees) for the collection site of the hocicudo.
Musser and Carleton (1993)
and
Hershkovitz (1994)
assumed that the hocicudo and the rat roux were the same specimen and as a result, erroneously suggested that the bibliographical
type
of
O
. rufus
was collected at that latitude, which falls outside of Paraguayan borders. Moreover, it was assumed that
Paraguay
was inhabited only by a blackish form of
Oxymycterus
described as
O
. delator
Thomas
(a report by de
Roguin, 1986
:
1819-1829
, of a reddish specimen collected in 1982 near Ciudad del Este in eastern
Paraguay
, and identified as
O
. rutilans
--a synonym of
O
. rufus--
was overlooked.)
As
a result, currently most authorities list the
type
locality of
O
. rufus
as lying outside
Paraguay
. Our records, together with the observation of de
Roguin (1986)
, of a relatively reddish form from
Paraguay
suggest, in accordance with
Contreras and Teta (2003)
, among others, that Azara may indeed have used a Paraguayan mouse to describe the rat roux. In turn, this implies that the
type
locality of
O
. rufus
may be restricted to a location within
Paraguay
. We note that our records are about 275 and
340 km
from San Ignacio, the area to which
Galliari
et al
. (1996)
restricted the
type
locality of
O
. rufus
, but more than likely in Azara’s time forest habitats were continuous between the two areas.
We are aware of the important nomenclatorial changes that the scenario we pose would cause in
Oxymycterus
taxonomy. But we also note that that taxonomy would revert, at least in part (i.e., the placement of the
O
. rufus
type
locality within
Paraguay
), to a scenario that was abandoned only recently (i.e.,
Musser & Carleton 1993
;
Hershkovitz 1994
). Here, we do not innovate in this respect and refer these Paraguayan specimens to
O
. misionalis
, preferring to reserve further treatment of this problem for an upcoming contribution focused on
Oxymycterus
systematics by D’Elía and collaborators.
On a related issue, Musser and Carleton (2005) considered
O
. misionalis
and
O
. judex
as junior synonyms of
O
. quaestor
Thomas. It
is worth noting that a cyt
b
haplotype recovered from the Paraguayan specimen TK 12151 (
EU449517
) is only 0.5 % divergent from
O
. misionalis
(one specimen) from
Argentina
and from
O
. judex
(two specimens) from
Brazil
, and is 2.8 – 2.9 % divergent with haplotypes referred to
O
. quaestor
(three specimens) from
Brazil
. We recognize that the relationship among
misionalis
,
judex
, and
quaestor
is yet another unresolved taxonomic issue within the genus
Oxymycterus
, and therefore, pending further study, we prefer to follow the most recent reviews (Oliveira, 1998 and
Hoffmann
et al.
2002
), in recognizing
O
. misionalis
as a valid species.
Comments
: These records constitute the first citation of the
O
. misionalis
for
Paraguay
(but see above, especially concerning the specimen reported by de
Roguin 1986
). This report confirms that two species of
Oxymycterus
inhabit
Paraguay
; these are currently referred to as
O
. delator
and
O
. misionalis
. Specimens of the latter were collected in low secondary forest and abandoned crop fields. A female and a male collected in February (2007) had vagina open and scrotal testes, respectively. An adult female collected in June (2006) had the vagina closed. Others (all adults) captured and released in June included one female with vagina closed, three males with testes scrotal, and one with testes abdominal. Other sigmodontines collected in the same trap lines with
O
. misionalis
include
Akodon montensis
,
Calomys callosus
(Rengger)
, and
Necromys lasiurus
.