Molecular systematics of terraranas (Anura: Brachycephaloidea) with an assessment of the effects of alignment and optimality criteria
Author
Padial, José M.
padialj@carnegiemnh.org
Author
Grant, Taran
taran.grant@ib.usp.br
Author
Frost, Darrel R.
padialj@carnegiemnh.org
text
Zootaxa
2014
2014-06-26
3825
1
1
132
journal article
10.11646/zootaxa.3825.1.1
1175-5326
4920347
1F6DEC4F-6E2A-45B6-A71C-3D6CF783FEDF
Brachycephalidae
This taxon includes the sister taxa
Brachycephalus
and
Ischnocnema
, a relationship first discovered by
Heinicke
et al.
(2007)
, who placed most southeastern Brazilian taxa then referred to “
Eleutherodactylus
”
(
Frost
et al.
, 2006
) in a redelimited
Ischnocnema
. Previously,
Caramaschi & Canedo (2006)
had restricted
Ischnocnema
to
Ischnocnema verrucosa
, and placed it in the synonymy of
Eleutherodactylus
. A new test of the sister relationship of
Ischnocnema
and
Brachycephalus
was recently provided by
Canedo & Haddad (2012)
, who found the taxa to be reciprocally monophyletic in both maximum likelihood and Bayesian analyses. Interestingly, their parsimony analysis of a similarity alignment placed
Brachycephalus
as the sister of
Haddadus binotatus
, another taxon from southeastern
Brazil
. Such a relationship had never been proposed, and although it is not corroborated in our analyses, it surely deserves future attention, particularly with regard to the effects of alignment and optimality criterion.
Brachycephalus
.—This genus of small, diurnal frogs that usually are brightly colored and contain tetrodotoxin (
Pires
et al.
2005
) is endemic to southeastern
Brazil
. Its unique pectoral girdle has long been recognized as a synapomorphy of the genus (
Izecksohn, 1971
;
Pombal & Gasparini, 2006
) and was used to synonymize
Psyllophryne
(
i.e.
,
P. didactyla
and
P. hermogenesi
) with
Brachycephalus
by
Kaplan (2002)
, a synonymy subsequently validated by analyses of DNA sequences that found the two species to be nested among other species of
Brachycephalus
(
Clemente-Carvalho
et al.
, 2011
; current results).
Frost
et al.
(2006)
,
Heinicke
et al.
(2007)
,
Hedges
et al.
(2008a)
, and
Pyron & Wiens (2011)
only included
B. ephippium
in their analyses, and
Canedo & Haddad (2012)
added
B.
cf.
didactylus
.
Clemente-Carvalho
et al.
(2011)
provided the first extensive molecular phylogenetic analysis of the genus by including 14 of the 18 currently recognized species (
Pombal & Izecksohn, 2011
). Inadequate outgroup sampling (the tree was rooted on a single terminal of
Ischnocnema
) prevented the monophyly of
Brachycephalus
, the position of
Psyllophryne
within Brachycephaloidea, or the sister relationships with
Ischnocnema
from being tested in that study. Nevertheless, our results agree with Clemente-Carvalho
et al.
’s (2011) Bayesian analysis of the concatenated nuclear and mitochondrial data in recovering two major sister clades, a southern clade formed by locally endemic species restricted to the high and humid Atlantic Forest of
Paraná
(
B. brunneus
,
B. ferruginus
,
B. izecksohni
,
B. pernix
, and
B. pombali
) and the northern clade, allopatric to the first, distributed from farther north in
Paraná
to
Espírito Santo
(
B. alipioi
,
B. didactylus
,
B. ephippium
,
B. garbeanus
,
B. hermogenesi
,
B. nodoterga
,
B. pitanga
,
B. toby
, and
B. vertebralis
), with the two species of the former
Psyllophryne
placed separately in the second clade.
Ischnocnema
.—
This genus is distributed within the Atlantic Forest of south, southeastern, and northeastern
Brazil
and
Misiones
,
Argentina
(
Canedo & Haddad, 2012
;
Frost, 2014
). The monophyly of the genus was hypothesized by
Heinicke
et al.
(2007)
and
Hedges
et al.
(2008a)
, who analyzed 5 of the 33 species. A more complete test of generic monophyly was recently provided by
Canedo & Haddad (2012)
in a study that was published while the present manuscript was being written, which unfortunately precluded the use of their data in our analyses. Nevertheless, their taxon sampling of other brachycephalids was large enough (214 species) to provide a strong test of the monophyly of
Ischnocnema
. Their major finding was a polyphyletic
Ischnocnema
sensu
Hedges
et al.
(2008a)
with three named species (
I. paulodutrai
,
I. ramagii
, and
I. vinhai
) and two unnamed species recovered as part of the
Pristimantis conspicillatus
species group. Also,
Ischnocnema bilineata
was found to be the sister of a clade composed of the genera
Noblella
and
Barycholos
in
Holoadeninae
. Accordingly,
Canedo & Haddad (2012)
placed three nominal species of
Ischnocnema
in
Pristimantis
, but left "
Eleutherodactylus
"
bilineatus
Bokermann, 1975
"1974" as
incertae sedis
within
Holoadeninae
6
(of
Craugastoridae
, below). For the remaining species of
Ischnocnema
, they recognized four monophyletic species series and left two species unassigned to any group, although five species were only tentatively assigned to groups based on their morphology. We follow their assignment of species to species series (see Appendix 2).