Proposal (584) to South American Classification Committee
Recognize subfamilies in the
Cracidae
A. Recognize Cracidae subfamilies Cracinae and
Penelopinae (II)
B. Recognize Cracidae subfamily Ortalidainae
This is essentially a re-run of
Proposal 285A, to
recognise Cracidae subfamilies, which ended up 5-5 in the voting last
time. Several of those committee members
who voted against the proposal felt it would be preferable to have a
higher-level name for the chachalacas instead of placing them incertae sedis or in a subfamily to
which they are not very closely related.
A higher-level name is now available for Chachalacas, so this issue
requires reconsideration.
Molecular studies have shown the
chachalacas to be a more or less equally ancient lineage to guans and
curassows. Pereira et al. (2002), using
‘molecular clock’ techniques, hypothesised the following periods (95% confidence
interval) for major divisions in the Cracidae: 'core' Guans vs. other Cracids -
26.9-40.6 million years ago (Early Oligocene); Oreophasis from the remainder: 26.6-36.1 mya (Early Oligocene); and
Ortalis from Curassows: 25.8-36.5 mya
(Early Oligocene). These hypothesised
divisions are as deep or deeper than those between some passerine and other subfamilies
recognised by AOU-SACC.
A subfamily name for the chachalacas
is now available (Donegan 2012). The
description was not straightforward, given issues with the generic name Ortalis (originally described as "Ortalida") and the need to avoid
homonymy with higher-level names for invertebrates. The tribal name Ortalidaini is now described,
making the subfamily name Ortalidainae available. In the description of the tribe, this rank
was expressly not a recommendation for rank vis-a-vis subfamily treatment.
Most authors on cracids over the
last few decades have recognised divisions below the family level in this
group. Per Donegan (2012):
"Vaurie (1968) recognised three major divisions
within the family based on morphological data: the Guans and Chachalacas
(Penelopini: Chamaepetes, Penelopina,
Penelope, Pipile, Aburria and Ortalis),
the Curassows (Cracini: Pauxi, Mitu,
Nothocrax and Crax) and the
Horned Guan (Oreophasini: Oreophasis).
Delacour & Amadon (1973) re-lumped Oreophasini into Penelopini. Del Hoyo
(1994) and del Hoyo & Motis (2004) ranked Delacour & Amadon (1973)’s
tribes as sub-families."
More recently, Fjeldså (2013)
recognised chachalacas as a major ancient lineage alongside others in Cracids traditionally
recognised as subfamilies or tribes.
Recent phylogenetic studies such as Pereira et al. (2002, 2009), Eo et
al. (2009), and Frank-Hoelfich et al. (2007) all recognised cracid subfamilies. Following proposal 560, SACC does not now
deal with tribes, so the options available here are subfamilies or nothing.
Part A of this proposal would be to
recognise the two traditional subfamilies that occur in South America, but
(following molecular studies) placing Ortalis
tentatively in the Cracinae. Part B
would be to treat Ortalidainae separately from the other two groups. Rejection of the proposals would be a vote
not to recognise subdivisions at all within this family.
See proposal 285A and the papers
cited below for a more detailed discussion of the differences between these
groups.
References:
Donegan, T.M.
2012. A new group name for the Chachalacas (Aves: Cracidae: Ortalis). Conservación Colombiana 17: 41–44.
http://www.proaves.org/proaves/images/RCC/Con_Col_17_41-44_Ortalidaini.pdf
Fjeldså, J.,
2013. Avian
classification in flux. pp. 77-146. In: Handbook of the Birds of the World,
Special: New species and global index. J. del Hoyo, et al. (Eds.). Lynx
Edicions, Barcelona.
Other references cited in Donegan
(2012) and the previous proposal.
Thomas Donegan, August 2013
Comments
from Stiles: “YES on A
and B, given the nearly equivalent ages of the chachalacas vs. the other two
cracid lineages according to recent genetic data; subfamily status seems
appropriate.”
Comments
from Nores: “NO on A and B. Although I do not disagree
that subfamilies should be included, I think that it should be considered in a
second stage. I do not know when we have to end this stage. The same criteria
would apply to include subspecies.”
Comments
from Pacheco: “YES
on A and B. Considerando que as linhagens são confirmadamente
divergentes. Prefiro tratá-las no nível de subfamília que em nível de tribo.
Defendo agora que a adoção de subfamílias no SACC, quando bem fundamentadas,
pode ser implementada casualmente. “
Comments from Zimmer: “YES on A. These lineages are ancient, and should be
formally recognized. YES on B. YES.
Given the relatively ancient nature of the lineage relative to other
lineages of cracids, I think this is the desired course.”
Comments
from Jaramillo: “Yes on
both A and B, which unless I am reading it incorrectly would give us three
subfamily level groups within the family.”
Comments
from Remsen: “YES to
both A and B. Even if the dating is only
approximately correct, these three lineages are as old as many taxa ranked as
families. This is surprising from the
phenotype standpoint because in terms of morphology and plumage, Ortalis are superficially very similar
to Penelope.
“Note that
David (2014) has pointed out in Zootaxa
that the formulation of the name itself is incorrect, so if the proposal does
pass, we will have to deal with that – if you Google Scholar your way to the
article, you can download a pdf or just ask me for a copy. From David (2014): ” Under the
circumstances, the misformed tribe name "Ortalidaini" is to be
corrected to Ortalisini Donegan, 2012 (Articles 32.5.3.2 and 35.4.1) with
authorship, date and place of publication unchanged (Articles 32.2.2 and
33.2.2).” However,
Donegan just told me that “Ortalisini” may be pre-occupied in Diptera and that
ICZN is now evaluating this. I suggest
we defer implementation until this sorts itself out.
Comments
from Stotz: “YES. I think given the age of the groups and the
fact that most people recognize subfamilies in Cracidae that turn out not to be
monophyletic, I think we need to fix that.
Additional
comments from Remsen:
“After reading Hosner et al. (2016), I switch to a NO on this one. Hosner et
al. (2016; Fig. 3) showed that although the Cracidae itself is an ancient
group, all modern species likely evolved from a single shared ancestor ca. 12
MYA. Thus the lineage that contains
extant taxa is not much older than most genera and in fact younger than many
genera (e.g. in Furnariidae). In retrospect,
this makes sense because the morphological diversity of extant cracids is
remarkably conservative – the chachalacas look basically “identical” to small Penelope guans, etc. Therefore, even though there are deep
divergences among the three primary lineages, they are young and
morphologically very similar. Although
we have no official definition of subfamily, the cracid lineages certainly
don’t fit my personal one (which is dominated by lineage age as the only
consistently defensible, objective criterion).
Also, and this is just a technicality, extralimital Oreophasis should also be ranked as a subfamily if the other three
are.”
Additional
comments from Stiles: “I agree also, so
NO!”
Comments
from Cadena: “NO. But
not because anything in particular related to clades within the Cracidae. What
is a subfamily? I don't think anyone of us knows and because we have not agreed
on criteria to recognize clades at this level, I do not think it is worthwhile
to introduce this category at all in our classification right now. In addition,
is there any particular good reason why we worry about recognizing subfamilies
in some families but not in others? I don't think so and doing this in some
cases and not in others in the absence of clear guidelines leads to
inconsistencies in our classification. The above said, I think it would be
extremely good if we could establish some criteria to recognize clades not only
at the subfamily level but also at the family and order level (these ranks
carry a lot of inertia but they are also defined quite arbitrarily and thus
inconsistently). I think Van's ideas about considering clade age are fantastic
and I absolutely loved his talk on this topic in the Colombian ornithology
congress in 2007 (imagine a classification in which names convey information
not only about relationships but also about clade ages!). In addition, I would
argue this is a good time to think about this issue because we are now
sufficiently close to having good enough time-calibrated trees to establish some
sort of highly objective criteria for assessing rank to clades based on their
ages. So I say lets talk about this in general, agree on criteria, and then
work on particular cases.”