• Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.

    Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Rallidae (3 Viewers)

García-R J.C., Gibb G. & Trewick S., 2014. Deep global evolutionary radiation in birds: Diversification and trait evolution in the cosmopolitan bird family Rallidae. Mol. Phylogen. Evol. In press

abstract

García-R J.C., Gibb G. & Trewick S., 2014:

Our molecular analyses confirm that Sarothrura and Canirallus, which were previously placed in Rallidae have affinities outside the family, and are better treated as a distinct family Sarothruridae
 
García-R, Gibb & Trewick 2014. Eocene diversification of crown group rails (Aves: Gruiformes: Rallidae). PLoS ONE 9(10): e109635. [article] [pdf]
What does "crown group" mean?

Also struggling to find the type species of the family - or any member of the type genus - in their phylogeny (Figs. 2, 3), doesn't help understand the family well :C
 
What does "crown group" mean?

Also struggling to find the type species of the family - or any member of the type genus - in their phylogeny (Figs. 2, 3), doesn't help understand the family well :C
Crown group = monophyletic group formed by all the ancestors of extant species, back to their most recent common ancestor.
This is usually opposed to pan group = monophyletic group formed by the crown group, plus all the extinct species more closely related to it than to any extant species.
(As far as extant taxa are concerned, there is no difference.)
 
Last edited:
Thanks, though unfortunately not a lot of use as they don't explain which their crown group taxa are and aren't - are they excluding Rallus and Porzana from the crown group, given their exclusion of them from the data set?
 
The taxa that are included in the dataset are presumably just those for which a complete mitochondrial genome was available at the time of the analysis.

They estimate a date for the origin of the crown-group, which means the date when the most recent common ancestor of all extant rallids occured. This is of course different from the date of origin of the pan group, which would be the date of the divergence between the rallid lineage and its extant sister group.
Extant species are always (by definition of the term) all within the crown group of any taxon they belong to. The difference between crown and pan groups is only in which past taxa (either known from fossils, or just inferred to have existed from phylogenetic analyzes) are placed in the group together with these extant species.
(To be complete: species that are part of the pan group but not of the crown group are typically called "stem species"; they are all extinct by definition; together they may be referred as forming "the stem group"--although a "group" so-defined is always paraphyletic, hence not a "natural group" in the cladistic sense.)

Excluding Rallus from crown-group Rallidae is not possible: it is the type genus of the family, thus (unless you regard the family as invalid), it is a Rallidae by definition; and as it is extant, it is in the crown group of its family by definition. Porzana is extant as well, thus to exclude it from crown-group Rallidae would require to exclude it from the family--but no reasons exist to do this.
 
Last edited:
But the wikipedia diagram shows you can have more than one crown group in a taxon (family); annotating their diagram [by Peter coxhead, CC-BY-SA license], this could be the case . . .??
 

Attachments

  • 0001.jpg
    0001.jpg
    43.4 KB · Views: 149
Well, of course you can define a crown group at any taxonomic level. Thus if you have a family with two subfamilies, each subfamily can have its own crown group. But the crown group of the family will continue to include all the extant members of the family.
Additionally, all the current evidence indicates that Porzana (sensu stricto) is sister to the coots and moorhens, and not at all closely related to Rallus, which on the other hand is very close to Gallirallus. Thus each of the two members of your "right-side crown group" is closer to some members of your "left-side crown group" than they are to one another.
 
Last edited:
Thanks! It's a pity that the authors didn't include the type species of the family, nor any species from the most speciose genus, in their data set. Poor preparation and planning.
 
But the main aim of this work was to "use complete mitochondrial genomes to assess temporal diversification within Rallidae", not to solve all the relationships within the family.
If you want a more extensive taxon sampling (but a more gappy and imbalanced data set, which would presumably make dating more hazardous), you can always turn to their other study...:
http://www.sciencedirect.com/science/article/pii/S1055790314003200
http://ars.els-cdn.com/content/image/1-s2.0-S1055790314003200-gr1.jpg
http://ars.els-cdn.com/content/image/1-s2.0-S1055790314003200-gr2.jpg
http://ars.els-cdn.com/content/image/1-s2.0-S1055790314003200-gr3.jpg
http://ars.els-cdn.com/content/image/1-s2.0-S1055790314003200-gr4.jpg
http://ars.els-cdn.com/content/image/1-s2.0-S1055790314003200-gr5.jpg
 
Last edited:
Thanks l_r!

Shame it isn't publicly available :C anyone know how to get past the racketeers who are blocking access to sciencedirect?
Proposal (651) to SACC:

Resurrect Porphyriops for Gallinula melanops
From this tree - if correct - not only does Gallinula melanops need to be split from Gallinula, but also G. ventralis and G. mortierii (already done by IOC, as Tribonyx); and more oddly, also Porzana needs to be split in two, with P. porzana [type!], P. carolina and P. fluminea in their "Fulica" clade, and P. parva, P. pusilla, etc. in their [presumably wrongly named!] "Porzana" clade. Can we look forward to Little & Baillon's Crakes etc., being transferred to Amaurornis? Might these additions bring in any older different genus names with them? Oh, and some other Porzana in their "Laterallus" clade, and a couple of Amaurornis in their "Gallicrex" clade . . . wot a mess!!
 
Last edited:
and more oddly, also Porzana needs to be split in two, with P. porzana [type!], P. carolina and P. fluminea in their "Fulica" clade, and P. parva, P. pusilla, etc. in their [presumably wrongly named!] "Porzana" clade. Can we look forward to Little & Baillon's Crakes etc., being transferred to Amaurornis? Might these additions bring in any older different genus names with them? Oh, and some other Porzana in their "Laterallus" clade, and a couple of Amaurornis in their "Gallicrex" clade . . . wot a mess!!
There have been data hinting at this published since at least 2002--it's just that nobody seems to have seriously thought about translating them into a taxonomy until very recently... ;)
See also my posts #3 and #13 in this thread.
The type of Amaurornis Reichenbach, 1853 is Gallinula olivacea Meyen, 1834 (by original designation): not included in the García-R et al study, but all other data sources show that it falls in their "Gallicrex" clade, thus the name can't be used for their "Porzana" group either. TiF and H&M4 use Zapornia Stephens, 1824 (type "Rallus pusillus Gmelin, 1789" = Rallus pusillus Pallas, 1776, by original monotypy) for this group.
 
Last edited:
TiF and H&M4 use Zapornia Stephens, 1824 (type "Rallus pusillus Gmelin, 1789" = Rallus pusillus Pallas, 1776, by original monotypy) for this group.
Mmh. Looking at this a bit closer, the above seems in fact incorrect.

TiF and H&M4 actually take Zapornia from Leach, 1816, not from Stephens, 1824.

As it stands, this may be somewhat problematic, though. The only included species there is cited as Zapornia minuta. This species is neither described nor illustrated, and no other indication is given, thus (1) the species group name is certainly not made available there, and (2) the only way that the genus-group name can be deemed to have been made available, is through its use in combination with an available specific name (under Article 12.2.5). In other words, "Zapornia minuta" must be a recombination of a species name that was made available somewhere else--or there is no "Zapornia Leach". Is there any other plausible candidate than Rallus minutus Gmelin, 1789, based on "Le Petit Râle de Cayenne" of Buffon = Rallus flaviventer Boddaert, 1783...?

EDIT - No, OK, I get it: Gallinula minuta Montagu, 1813 is the type species (same specimen as listed by Leach, shot in 1809 by W. Tucker, Esq., at Ashburton, Devon--here described and named as a new species).
 
Last edited:
How can Zapornia have priority over Porzana when Leach (1816) not even delivered a proper description for the genus Zapornia?

http://www.biodiversitylibrary.org/item/62685#page/44/mode/1up

The relevant article of the Code is 12.2.5

12.1. Requirements. To be available, every new name published before 1931 must satisfy the provisions of Article 11 and must be accompanied by a description or a definition of the taxon that it denotes, or by an indication.

12.2. Indications. For the purposes of this Article the word "indication" denotes only the following:
...
12.2.5. in the case of a new genus-group name, the use of one or more available specific names in combination with it, or clearly included under it, or clearly referred to it by bibliographic reference, provided that the specific name or names can be unambiguously assigned to a nominal species-group taxon or taxa;

So no description is required, although the availability of the name depends on whether the association with Montagu's name is really "unambiguous".
 

Users who are viewing this thread

Back
Top