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Tyrannides (1 Viewer)

Jim LeNomenclatoriste

Taxonomy and zoological nomenclature
France
Martín Nicolás Fasanelli,Pablo S. Milla Carmona,Ignacio María Soto,Diego Tomás Tuero (2022) Allometry, sexual selection and evolutionary lines of least resistance shaped the evolution of exaggerated sexual traits within the genus Tyrannus
Variational properties hold a fundamental role in shaping biological evolution, exerting control over the magnitude and direction of evolutionary change elicited by microevolutionary processes that sort variation, such as selection or drift. We studied the genus Tyrannus as a model for examining the conditions and drivers that facilitate the repeated evolution of exaggerated, secondary sexual traits in the face of significant functional limitations. In particular, we explore the role of allometry, sexual selection and their interaction, on the diversification of tail morphology in the genus, assessing whether and how they promoted or constrained phenotypic evolution. Non-deep-forked species tend to show reduced sexual dimorphism and moderate allometric variation in tail shape. The exaggerated and functionally constrained long feathers of deep-forked species, T. savana and T. forficatus, which show both marked sexual dimorphism and allometric tail shape variation, independently diverged from the rest of the genus following the same direction of main interspecific variation accrued during the evolution of non-deep-forked species. Moreover, the latter direction is also aligned with axes summarising sexual dimorphism and allometric variation on deep-forked species, a feature lacking in the rest of the species. Thus, exaggerated tail morphologies are interpreted as the result of amplified divergence through reorientation and co-option of allometric variation by sexual selection, repeatedly driving morphology along a historically favoured direction of cladogenetic evolution.
 

Taphrospilus

Well-known member
A question on Elaenia obscura (d'Orbigny & Lafresnaye, 1837). If I follow https://www.avespress.com/uploads/texteditor/zoological_bibliography_5_4.pdf p 139-140 I ask myself why the name is still the valid one in IOC World bird list here.

The name guillemini was proposed as a nomen novum in the mistaken belief that Muscipeta obscura was preoccupied by Muscicapa obscura Vieillot, 1818 (see footnote to Voyage p. 319). Hellmayr (1925: 29fn) rejected the preoccupation and used the name obscura as did Hellmayr (1927), Traylor (1979a: 34)151 and Dickinson & Christidis (2014). However, Muscipeta obscura d’Orbigny & Lafresnaye while not preoccupied by Vieillot’s name is preoccupied by Muscipeta obscura Drapiez, 1827, and on this basis the name guillemini here replaces obscura – and, as always, the nomen novum takes on the original type material.

OD here
Muscipeta Guillemini d'Orbigny, 1840 here

Not that sure where to find Drapiez or is it here Muscipeta obscura?
 

l_raty

laurent raty
A question on Elaenia obscura (d'Orbigny & Lafresnaye, 1837). If I follow https://www.avespress.com/uploads/texteditor/zoological_bibliography_5_4.pdf p 139-140 I ask myself why the name is still the valid one in IOC World bird list here.

The name guillemini was proposed as a nomen novum in the mistaken belief that Muscipeta obscura was preoccupied by Muscicapa obscura Vieillot, 1818 (see footnote to Voyage p. 319). Hellmayr (1925: 29fn) rejected the preoccupation and used the name obscura as did Hellmayr (1927), Traylor (1979a: 34)151 and Dickinson & Christidis (2014). However, Muscipeta obscura d’Orbigny & Lafresnaye while not preoccupied by Vieillot’s name is preoccupied by Muscipeta obscura Drapiez, 1827, and on this basis the name guillemini here replaces obscura – and, as always, the nomen novum takes on the original type material.

OD here
Muscipeta Guillemini d'Orbigny, 1840 here

Not that sure where to find Drapiez or is it here Muscipeta obscura?

If Muscipeta obscura d'Orbigny & Lafresnaye 1837 is in wide use (used as a valid name in at least 25 works, published by at least 10 authors in the last 50 years and encompassing a span of not less than 10 years), and Muscipeta obscura Drapiez 1827 has not been used as a valid name after 1899, ICZN 23.9 applies and prevailing usage must be preserved.
In principle, an act of reversal of precedence, which would formally give priority to the name in use, should be published.
(But the actual publication of this act may not be of primary importance in this particular case, because it seems improbable that anyone might suddenly start using Drapiez's obscura as the valid name of a taxon, which would be needed to end the situation under which 23.9 protects d'Orbigny & Lafresnaye's name.)

PS - It may be questionable that d'Orbigny's "belief that Muscipeta obscura was preoccupied by Muscicapa obscura Vieillot, 1818" was really "mistaken". Of course the two names are not primary homonyms, but if d'Orbigny was of the opinion that Vieillot's species had to be classified in Muscipeta, then to him they were secondary homonyms, and he was completely right to replace the name.
 
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Taphrospilus

Well-known member
(But the actual publication of this act may not be of primary importance in this particular case, because it seems improbable that anyone might suddenly start using Drapiez's obscura as the valid name of a taxon, which would be needed to end the situation under which 23.9 protects d'Orbigny & Lafresnaye's name.)
What does that mean primary importance or when is a publication considered as primary important?
 

l_raty

laurent raty
What does that mean primary importance or when is a publication considered as primary important?

From discussions I have had or read, I gather that publishing acts of reversal of precedence is often perceived as a burden -- people tend to be happy with the Code saying that prevailing usage must be maintained, and to just leave things "as they are" if they can. (This is certainly not what the Code says they should do, yet this is something I have seen being advocated even by some Commissioners.)

The problem is, if you leave the situation as it is instead of acting, there may be a risk that the conditions of 29.3 stop being fulfilled, making later action impossible. This may be due to, either, (1) some publications where the used name appeared slipping out of the "immediately preceding 50 years" time window, and not being replaced by new ones, or, (2) the disused name being, for some reason, put back into usage. (But note that the name must then have been put back into usage in a way that was not deliberately contrary to Art. 23.9 -- see 23.9.6.)

I would regard it as more important to have an actual act of reversal published in cases where waiting seems to imply a bigger risk that the conditions stop being fulfilled. You can feel free to prove me wrong, but I doubt that Drapiez's species can be identified, hence I do not perceive the risk that his name be put back into usage as very high. This is admittedly but my own subjective appreciation of the case, however.
 

Taphrospilus

Well-known member
Sorry now I have to come back as I am a little bit confused. I do not think that Drapiez name is the issue to be made a valid one. As I understood Elaenia obscura (d'Orbigny & Lafresnaye, 1837) should be replaced by Elaenia guillemini d'Orbigny, 1840 as the first name is already used (peoccupied) by Drapiez and at that time even attributed to the same genus Muscipeta. Or is a Nomen dubium not seen as a availble name according the Code? So the name was there even if d'Orbigny was not aware of it and changed it due to another reason in his footnote.

1655803399493.png
Vieillots publication here.
I understand that authorities don't like this kind of changes but why create rules if they are not followed.
 
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l_raty

laurent raty
A nomen dubium is unquestionably an available name, and does compete for homonymy.

But ICZN 57.2 does not make a junior primary homonym necessarily invalid -- there are exceptions to this rule :
57.2. Primary homonyms
Identical species-group names established for different nominal taxa when originally combined with the same generic name (see also Articles 11.9.3.2 and 57.8.1) are primary homonyms [Art. 53.3] and the junior name is permanently invalid (but see Article 23.9.5) except when:
57.2.1. its use as a valid name (a nomen protectum) is maintained under the conditions specified in Article 23.9
, or
57.2.2. it is conserved by the Commission under Article 81, or
57.2.3. it, but not its senior homonym, is included in a relevant adopted Part of the List of Available Names in Zoology (see Article 79.4.3).
As the conditions specified in ICZN 23.9 are fulfilled, we are in a situation that falls under ICZN 57.2.1, and the homonymy does not make d'Orbigny & Lafresnaye's name invalid. The only easy way that the conditions specified in ICZN 23.9 might cease to be fulfilled would be if someone started using Drapiez's name as the valid name of a taxon.

(It would actually be easier to justify a rejection of obscura due to the replacement by d'Orbigny as a result of a secondary homonymy with Vieillot's name. ICZN 59.3:
59.3. Secondary homonyms replaced before 1961 but no longer considered congeneric
A junior secondary homonym replaced before 1961 is permanently invalid unless the substitute name is not in use and the relevant taxa are no longer considered congeneric, in which case the junior homonym is not to be rejected on grounds of that replacement.
D'Orbigny replaced Muscipeta obscura d'Orbigny & Lafresnaye with M. guillemini due to Vieillot having named "une autre espèce de Moucherolle", i.e., another species of Muscipeta in d'Orbigny's own taxonomy ("Moucherolle" is French for Muscipeta in d'Orbigny's work, see the generic header on p. 317) by the same specific name : he clearly replaced it due to a perceived secondary homonymy, and 1840 was clearly before 1961; if you read the replacement name as having lost its "not in use" status as a result of it having been used by Dickinson & Lebossé in 2018, you might argue that this replacement makes the replaced name permanently invalid under 59.3.)
 
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l_raty

laurent raty
I was wondering if Drapiez using again Muscipeta obscura Drap. in 1837 adds anything? (Zool. VII 1837 48) Which I cannot find.
sec.2:pt.18=pp.4451-4690 [O Nigrum-Pallens] - Index animalium - Biodiversity Heritage Library .

It can be a bit confusing, but Sherborn used to maximize space use in his work by completing unfinished lines on the previous or next line, depending on where space was available.
[Zool. VII 1837 48.
is, I believe, intended as the end the next entry
obscura Muscipeta, A. d'Orbigny & Lafresnaye, Syn. Av. Amér. mérid. in Magasin de
 
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Jim LeNomenclatoriste

Taxonomy and zoological nomenclature
France
Is there a valid reason why we use Hemitriccus Cabanis & Heine 1860 instead of Musciphaga Lesson 1837 ?
The name was published in several works after 1899. However, is this enough to replace Hemitriccus with Musciphaga?







 
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l_raty

laurent raty
The name was published in several works after 1899. However, is this enough to

Beware that usage, as envisioned by Art. 23.9, is actual treatment of a name by an author as the valid name of a taxon. The mere citation of the name as an invalid synonym or for historical purposes does not qualify. In most/all of the links you list, the name is not actually accepted as valid -- Musciphaga obsoleta is directly cited in the synonymy of Hemitriccus diops, or in that of Hemitriccus diops obsoletus, or a discussion is provided that concludes that it is Hemitriccus diops. Such cases do not represent usage under Art. 23.9.

Miranda Ribeiro having moved diops to Musciphaga Lesson, and simultaneously described Musciphaga obsoleta as new in 1905, however, definitely qualify as usage of Musciphaga.

One single use of the senior synonmym after 1899 makes the conditions of 23.9.1 not fulfilled, and as a consequence no 'automatic' preservation of prevailing usage is possible. The only way to preserve usage is then via:

23.9.3. If the conditions of 23.9.1 are not met but nevertheless an author considers that the use of the older synonym or homonym would threaten stability or universality or cause confusion, and so wishes to maintain use of the younger synonym or homonym, he or she must refer the matter to the Commission for a ruling under the plenary power [Art. 81]. While the case is under consideration use of the junior name is to be maintained [Art. 82].

(My bolds.)

I.e., referring the case to the Commission is mandatory for anyone wishing to continue using the junior synonym in a Code-compliant way. Prevailing usage then becomes (temporarily) protected, as a result of the case being under the scrutiny of the Commission. There is no option for continuing using the junior synonym "until such time as this occurs".
 

Jim LeNomenclatoriste

Taxonomy and zoological nomenclature
France
Beware that usage, as envisioned by Art. 23.9, is actual treatment of a name by an author as the valid name of a taxon. The mere citation of the name as an invalid synonym or for historical purposes does not qualify. In most/all of the links you list, the name is not actually accepted as valid -- Musciphaga obsoleta is directly cited in the synonymy of Hemitriccus diops, or in that of Hemitriccus diops obsoletus, or a discussion is provided that concludes that it is Hemitriccus diops. Such cases do not represent usage under Art. 23.9.

Miranda Ribeiro having moved diops to Musciphaga Lesson, and simultaneously described Musciphaga obsoleta as new in 1905, however, definitely qualify as usage of Musciphaga.

One single use of the senior synonmym after 1899 makes the conditions of 23.9.1 not fulfilled, and as a consequence no 'automatic' preservation of prevailing usage is possible. The only way to preserve usage is then via:



(My bolds.)

I.e., referring the case to the Commission is mandatory for anyone wishing to continue using the junior synonym in a Code-compliant way. Prevailing usage then becomes (temporarily) protected, as a result of the case being under the scrutiny of the Commission. There is no option for continuing using the junior synonym "until such time as this occurs".
If I understand correctly, I hope, until no act is published to make the name Hemitriccus permanently valid, there is no justification for rejecting Musciphaga
 

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