Editing Algerian nuthatch (section)

== Taxonomy and systematics ==
===Discovery and nomenclature===
The Algerian nuthatch was discovered in [[Algeria]] by Jean-Paul Ledant, a Belgian naturalist and ornithologist, on 5 October 1975.<ref name="Laurence"/> Identifying it as quite different from other nuthatches, he wrote to the [[Academy of Sciences]] to report his discovery. Working on a revision of [[Sittidae]], they encouraged Ledant to return to the site.<ref name="Jacques Vielliard 1"/> He tried several times during the winter, but the mountain was too snowy to allow exploration. Ledant was finally accompanied by Jacques Vielliard in mid-April 1976 to observe nesting, which actually occurred later in the year due to the [[massif]] range's difficult climatic conditions. They had to wait until July to observe feeding behaviour and a few [[Fledgling (birds)|fledgling]]s, as well as to make recordings and call trials with songs of Corsican and Krüper nuthatches. Only a dozen pairs were observed, but on the 5–6 July, Vielliard killed a pair of adults that had finished feeding their chicks to be used as [[Type (biology)|type]] specimens.<ref name="Jacques Vielliard 2"/><ref name="Henri Balsac">{{cite journal|last=Balsac|first=Henri Heim de|title= Commentaires sur la découverte d'un élément imprévu de la faune paléarctique |language=fr|trans-title=Comments on the discovery of an unforeseen element of the Palearctic fauna|journal=Alauda |volume=44|issue=3|date=1976|pages=353–355|url=https://www.biodiversitylibrary.org/page/61349494|access-date=30 September 2024}}</ref><ref>{{cite journal|last1=Dubois |first1=Alain |last2=Nemésio |first2=André |url=https://www.mapress.com/zt/article/view/zootaxa.1409.1.1|title=Does nomenclatural availability of nomina of new species or subspecies require the deposition of vouchers in collections?|journal=Zootaxa |volume= 1409|date=2007|pages=16|doi=10.11646/ZOOTAXA.1409.1.1}}</ref> Kept in the describer's house, these specimens (the [[holotype]] and [[paratype]]) were seriously damaged after 2005 by insects, and were finally given to the [[National Museum of Natural History, France]] in 2015.<ref name="Laurent Vallotton">{{Cite journal |last=Vallotton|first=Laurent |date=2015 |url=https://www.researchgate.net/publication/297716482|title= The Altai Nuthatch: a missing link? |journal=9th International Meeting of Bird Curators|place= Darwin State Museum, Moscow |via=[[ResearchGate]]}}</ref>

The Algerian nuthatch was formally described in the journal ''Alauda'' by Jacques Vielliard in 1976 under its current name of ''Sitta ledanti''. This discovery greatly surprised the ornithological world, as the bird seemed to come from a "lost world" that has withstood the test of time, the [[Babor Mountains]].<ref name="Harrap"/> A species of bird [[endemic]] to the Mediterranean had not been discovered for nearly a century since the 1883 discovery of the Corsican nuthatch.<ref name="Henri Balsac"/><ref name="Jacques Vielliard 4"/>

In December 1976, the Swiss ornithologist Eric Burnier announced in the journal ''Nos Oiseaux'' that he had discovered the species independently on June 20 of the same year, before learning from a July 28 article in ''[[Le Monde]]'' that he had been preceded in his discovery and that the species had just been named.<ref name="Eric Burnier"/><ref>{{cite journal|last=-JB|first= J.|title=Un oiseau inconnu découvert en Algérie |language=fr|trans-title=An unknown bird discovered in Algeria|journal=Le Monde|date=28 July 1976|url=https://www.lemonde.fr/archives/article/1976/07/28/un-oiseau-inconnu-decouvert-en-algerie_2951235_1819218.html|archive-url= https://web.archive.org/web/20190916023836/https://www.lemonde.fr/archives/article/1976/07/28/un-oiseau-inconnu-decouvert-en-algerie_2951235_1819218.html|access-date=30 September 2024|archive-date= 16 September 2019}}</ref> He published a few drawings and field notes, explaining that he had spotted birds that he had judged to have the characteristics of the Corsican nuthatch and Krüper's nuthatch by song and then approached them only a few meters away. The only nuthatch in the [[Maghreb]] then known being the Eurasian nuthatch, which occurs in some localities of the Moroccan [[Rif]] and [[Atlas Mountains]] about 900 km from the Babor Mountains, he knew he was dealing with a new species.<ref name="Eric Burnier"/>

=== Phylogeny ===
[[File:Sitta krueperi - Christoph Moning - 2 (cropped).jpeg|thumb|alt=A grey bird with white face and orange body at the branch of tree |The male [[Krüper's nuthatch]] has the front half of the crown black, like the Algerian nuthatch; it is the closest relative of the latter species.]]
The Algerian nuthatch is placed in the [[subgenus]] ''Micrositta'', described by the Russian ornithologist [[Sergei Buturlin]] in 1916,<ref name="Matthysen 2010">{{cite book | last=Matthysen | first=Erik | title=The Nuthatches | publisher=A & C Black | publication-place=London | year=2010 | isbn=978-1-4081-2870-1 | oclc=727646681 | page=}}</ref> and has no [[subspecies]].<ref>{{cite web | title=Nuthatches, Wallcreeper, treecreepers, mockingbirds, starlings, oxpeckers – IOC World Bird List | website=IOC World Bird List – Version 11.2 | url=https://www.worldbirdnames.org/bow/nuthatch/  |archive-url=https://ghostarchive.org/archive/20220130/https://www.worldbirdnames.org/bow/nuthatch/  |archive-date=2022-01-30 |url-status=live| access-date=24 January 2022}}{{cbignore}}</ref> American ornithologist [[Charles Vaurie]] had grouped in 1957 the Corsican nuthatch, the [[red-breasted nuthatch]] (''Sitta canadensis'') and the [[Chinese nuthatch]] (''Sitta villosa''), which he considered to be very similar, in the "''Sitta canadensis''" group.<ref>{{cite journal|journal= American Museum Novitates|last= Vaurie|first= Charles|issue= 1854|year=1957|pages=1–26|title= Systematic notes on Palearctic birds. No. 29, The subfamilies Tichodromadinae and Sittinae|hdl= 2246/3596|url=https://digitallibrary.amnh.org/handle/2246/3596|issn=1937-352X|oclc=47720325}}</ref> In his 1976 description of the Algerian nuthatch, Vielliard devotes a portion of his paper to the possible relationships of the different species and their [[evolutionary]] history. He suggests that Vaurie stopped at a "superficial [[Morphology (biology)|morphological]] similarity" to bring the Corsican nuthatch closer to the red-breasted nuthatch, and that the Corsican species should rather form with Krüper's nuthatch a group known as the "Mesogean nuthatches", "where ''Sitta ledanti'' providentially fits in".<ref name="Jacques Vielliard 4"/> He considers it "tempting" to identify the [[fossil]] species ''Sitta senogalliensis'' (whose membership to the genus ''Sitta'' is discussed) described from the Upper [[Miocene]] in [[Italy]] as the ancestor of the Mesogean nuthatch group.<ref name="Jacques Vielliard 4"/>

In 1998, Eric Pasquet studied the [[cytochrome b]] gene in the [[mitochondrial DNA]] of about ten nuthatch species, including the various species of the ''Sitta canadensis'' group,<ref name="Packert2014 molecular">{{cite journal | title=Phylogeny of the nuthatches of the Sitta canadensis group and its evolutionary and biogeographic implications| first=Eric | last=Pasquet | name-list-style=amp | journal=The Ibis | volume=140 | issue=1 | pages= 150–156|date= January 1998| doi=10.1111/j.1474-919X.1998.tb04553.x }}</ref> which he defined as comprising six species, corresponding to those reported in the subgenus, ''Micrositta'':<ref name="Matthysen 2010"/> ''S. canadensis'', ''S. villosa'', ''S. whiteheadi'', ''S. yunnanensis'', ''S. krueperi'' and ''S. ledanti''. Pasquet concluded that the Corsican nuthatch is [[phylogeny|phylogenetically]] related to the Chinese nuthatch and the red-breasted nuthatch, these three species forming the [[sister group]] of a [[clade]] including Krüper's nuthatch and the Algerian nuthatch. The first three species would even be close enough to constitute subspecies, rejecting the "Mesogean" theory of Vielliard and thus confirming the conclusions of Charles Vaurie.<ref name="Packert2014 molecular"/> For the sake of [[taxonomic]] stability, however, all retain their full species status.<ref>{{cite book |last1=Thibault |first1= Jean-Claude|last2=Seguin |first2= Jean-François|last3=Norris |first3= Ken|url=https://archive.wikiwix.com/cache/index2.php?url=http%3A%2F%2Fwww.developpement-durable.gouv.fr%2FIMG%2Fpdf%2FPNA_Sittelle_corse.pdf%2Findex.html#federation=archive.wikiwix.com|title= Taxonomic status and biogeographic origin |location=Regional Natural Park of Corsica|date=2000|page=52 }}</ref> In 2014, Eric Pasquet and colleagues published a phylogeny based on [[Nuclear DNA|nuclear]] and mitochondrial DNA of 21 nuthatch species and confirmed the relationships of the 1998 study within the "''Sitta canadensis'' group", adding the [[Yunnan nuthatch]], which was found to be the most [[Basal (phylogenetics)|basal]] of the species.<ref name="Pasquet2014">{{cite journal|doi=10.1007/s10336-014-1063-7|url=https://link.springer.com/article/10.1007/s10336-014-1063-7|title=Evolution within the nuthatches (Sittidae: Aves, Passeriformes): molecular phylogeny, biogeography, and ecological perspectives|journal=[[Journal of Ornithology]]|date=April 2014|author1=Eric Pasquet |author2=Keith F. Barker |author3=Jochen Martens |author4=Annie Tillier |author5=Corinne Cruaud |author6=Alice Cibois|volume=155|issue=3|pages=755–765|bibcode=2014JOrni.155..755P |s2cid=17637707}}</ref>

The conclusions of these studies are in agreement with the morphology of the species, the red-breasted nuthatch, Corsican nuthatch and Chinese nuthatch sharing as a derived character the entirely black crown only present in males, a unique trait among the nuthatches and related families. The second clade, which includes Krüper's and Algerian nuthatches, have the front of the crown black in males, with this [[sexually dimorphic]] trait absent in juveniles.<ref name="Packert2014 molecular"/>

The simplified [[cladogram]] below is based on the [[phylogenetic analysis]] of Packert and colleagues (2014):<ref name="Pasquet2014"/>

{|
|-
| style="vertical-align:top;"|{{Clade|style=font-size:90%;line-height:100% <!--the line-height reduces line separation -->
|1={{clade
   |1=[[Yunnan nuthatch]] (''S. yunnanensis'')
   |2={{clade
      |1={{clade
         |1=Algerian nuthatch ('''''S. ledanti''''')
         |2=[[Krüper's nuthatch]] (''S. krueperi'')
         }}
      |2={{clade
         |1={{clade
            |1=[[Corsican nuthatch]] (''S. whiteheadi'')
            |2=[[Chinese nuthatch]] (''S. villosa'')
            }}
         |2=[[Red-breasted nuthatch]] (''S. canadensis'')
         }}
       }}
   }}
}}
|}

===Biogeography===
In 1976, the Swiss ornithologist [[Paul Géroudet]] suggested that the Mesogean nuthatches once inhabited a fairly continuous belt of [[conifers]] around the Mediterranean, which had become fragmented, leaving only a few hard-to-reach refuges where these different species were able to evolve in isolation.<ref name="Paul Géroudet ">{{Cite journal |last=Géroudet |first=Paul|title= À propos de la Sittelle kabyle |trans-title=About the Kabyle Nuthatch|journal=Nos Oiseaux|date=December 1976|volume=33|issue=8|pages=340–342|language=fr}}</ref> In 1998, his phylogeny having been established, Pasquet concluded that the paleogeographic history of the group would be as follows: the divergence between the two main clades of the "''Sitta canadensis'' group" appeared more than 5 million years ago, at the end of the Miocene, when the ''S. krueperi'' and ''S. ledanti'' clade settled in the [[Mediterranean basin]] at the time of the [[Messinian salinity crisis]]; the two species making up the clade diverged 1.75 million years ago. The other clade split into three, with populations leaving [[Asia]] from the east and giving rise to the North American red-breasted nuthatch, and then, about a million years ago, from the west, marking the separation between the Corsican and Chinese nuthatches.<ref name="Packert2014 molecular"/>