**5. Consequences of cladistic evaluations**

Progress was not only achieved at the level of orders, but also at the level of species, genera and families. With advent of DNA sequencing, more and more bird phylogenies were reconstructed from nucleotide sequences of one or more marker genes [in the beginning only mtDNA, later mtDNA and nuclear DNA (ncDNA) were used] from each species. These phylogenies provide a good resolution at the family and genus level, but often failed to infer divergences in the far past [13, 14].

As an example for the taxonomic changes within a bird family, I would like to document our own work on owl systematics [25, 26]. In **Figure 9**, a phylogram (reconstructed from cytochrome b sequences) indicates the major groupings within Tytonidae and Strigidae. In red, I have pointed out all the taxa, where DNA data either helped to define a species or a genus. In particular, the former genera *Nyctea, Ketupa* and *Scotopelia* were lumped into the genus *Bubo*, in order to avoid a polyphyletic genus *Bubo*. The former genus *Otus* was clearly polyphyletic and was split into new genera *Megascops*, *Psiloscops* and *Ptilopsis*. *Ninox superciliaris* from Madagascar is not a member of *Ninox*, but apparently belongs to *Athene*. Linné only recognized a single species *Tyto alba* with worldwide distribution. DNA data clears distinguish between *Tyto* from Europe/Africa (*Tyto alba* complex) and the New World (*Tyto furcata* complex). The Australasian Barn owls are quite diverse with four major lineages and many new species on isolated islands. Apparently, barn owls had evolved in Australia.

Similar splits and lumpings occurred in many bird families, just to name a few (see [27]) for a comprehensive list of accepted names).


**15**

**Figure 9.**

*DNA data.*

*DNA Analyses Have Revolutionized Studies on the Taxonomy and Evolution in Birds*

*Phylogeny of owls (Tytonidae, Strigidae) (after [26]). Names in red are those, which had changed because of* 

*DOI: http://dx.doi.org/10.5772/intechopen.97013*


*DNA Analyses Have Revolutionized Studies on the Taxonomy and Evolution in Birds DOI: http://dx.doi.org/10.5772/intechopen.97013*

#### **Figure 9.**

*Birds - Challenges and Opportunities for Business, Conservation and Research*

Progress was not only achieved at the level of orders, but also at the level of species, genera and families. With advent of DNA sequencing, more and more bird phylogenies were reconstructed from nucleotide sequences of one or more marker genes [in the beginning only mtDNA, later mtDNA and nuclear DNA (ncDNA) were used] from each species. These phylogenies provide a good resolution at the family and genus level, but often failed to infer divergences in the far past [13, 14]. As an example for the taxonomic changes within a bird family, I would like to document our own work on owl systematics [25, 26]. In **Figure 9**, a phylogram (reconstructed from cytochrome b sequences) indicates the major groupings within Tytonidae and Strigidae. In red, I have pointed out all the taxa, where DNA data either helped to define a species or a genus. In particular, the former genera *Nyctea, Ketupa* and *Scotopelia* were lumped into the genus *Bubo*, in order to avoid a polyphyletic genus *Bubo*. The former genus *Otus* was clearly polyphyletic and was split into new genera *Megascops*, *Psiloscops* and *Ptilopsis*. *Ninox superciliaris* from Madagascar is not a member of *Ninox*, but apparently belongs to *Athene*. Linné only recognized a single species *Tyto alba* with worldwide distribution. DNA data clears distinguish between *Tyto* from Europe/Africa (*Tyto alba* complex) and the New World (*Tyto furcata* complex). The Australasian Barn owls are quite diverse with four major lineages and many new

species on isolated islands. Apparently, barn owls had evolved in Australia.

• Warblers (*Sylvia, Acrocephalus, Cisticola, Hippolais, Phylloscopus*)

• Turdids (*Saxicola, Phoenicurus, Oenanthe, Turdus*)

(see [27]) for a comprehensive list of accepted names).

• Gulls and terns

• Bustards

• Waders

• Swifts

• Larks

• Shrikes

• Wagtails

• Pipits

• Tits

• Sparrows

• Finches and buntings

• Woodpeckers

• Petrels and albatrosses

Similar splits and lumpings occurred in many bird families, just to name a few

**5. Consequences of cladistic evaluations**

**14**

*Phylogeny of owls (Tytonidae, Strigidae) (after [26]). Names in red are those, which had changed because of DNA data.*

Thus a birder, who started his career 40 years ago will sometimes no longer recognize the Latin names of a species and their order of arrangement in modern field guides.

All these efforts have expanded the world checklist of birds. The IOC World Bird List 11.1 [27] actually (2021) comprises **10,806** extant species (and **158** extinct species) organized in **40** Orders, **252** Families and **2,353** Genera. **19,990** subspecies, their ranges and authors are also included. The number so of new bird species is increasing continuously. It has been speculated that we will end up with more than 18000 bird species, when all of them have been sequenced and re-classified [28].
