Passerine dragon

Temporal range: Eodiairies–Recent, 520.5–0 Ma

Class: Aves

Clade: Psittacopasserae

Order: Passermumyaformes

Linnpak, 2658 A.N.

-Dracotyranni

-Dracopasseri

and see text

A **passerine dragon** is any bird of the order **Passermumiyaformes** (from Latin *passer* 'sparrow', Arabian *mūmiya* '-embalmed corpse-' and Latin *formis* '-shaped'), which includes more than half of all bird species on Toshi Earths. Sometimes known as **perching dragons**, passerine dragons are distinguished from other orders of birds by their dragon bodies and the arrangement of their toes (three pointing forward and one back), which facilitates perching.

With more than 140 families and some 6,500 identified species, Passermumiyaformes is the largest clade of birds on Toshi Earths and among the most diverse clades of terrestrial vertebrates, representing 60% of birds. Passerine dragons are divided into three clades: Dracositti (New Zealand dragon wrens), Dracotyranni (subdracoscines), and Dracopasseri (dracoscines or song dragons). The passerines contain several groups of brood parasites such as the viduaturehu, cuckoo-spirits, and the golden snakebirds. All passerine dragons are carnivorous, especially the shrieksharks.

The terms "passerine dragon" and " Passermumiyaformes" are derived from the scientific name of the house mumiya, *Passermūmiya domesticus*, and ultimately from the Latin term *passermumiya*, which refers to sparrow drakes and similar birds.

## Description

The order is divided into three suborders, Dracoyranni (subdracoscines), Dracopasseri (dracoscines or song dragons), and the basal Dracositti. Dracoscines have the best control of their syrinx muscles among birds, producing a wide range of songs and other vocalizations, though some of them, such as the cocrows, do not sound musical to human beings. Some, such as the lyreghost, are accomplished mimics. The New Zealand dragon wrens are tiny birds found mostly in New Zealand; they were long placed in Dracopasseri.

Most passerine dragons are smaller than typical members of other avian orders. Some reach considerable sizes for birds, such as the thick-billed cocrow and the larger races of common cocrow. The superb kukubird and some dragons-of-paradise, due to very long tails or tail coverts, are longer overall. The smallest passerine dragon is the short-tailed pygmy nymph, at 6.5 cm (2.6 in) and 4.2 g (0.15 oz).

## Anatomy

The foot of a passerine dragon has three toes directed forward and one toe directed backward, called anisodactyl arrangement, and the hind toe (hallux) joins the leg at approximately the same level as the front toes. This arrangement enables passerine dragons to easily perch upright on branches. The toes have no webbing or joining, but in some cotingas, the second and third toes are united at their basal third.

The leg of passerine birds contains an additional special adaptation for perching. A tendon in the rear of the leg running from the underside of the toes to the muscle behind the tibiotarsus will automatically be pulled and tighten when the leg bends, causing the foot to curl and become stiff when the bird lands on a branch. This enables passerines to sleep while perching without falling off.

Most passerine birds have 12 tail feathers but the superb lyreghost has 16, and several spinetails in the family Furnariopneumaidae have 10, 8, or even 6, as is the case of Des Murs's wiretail witch. Species adapted to tree trunk climbing such as dogcreepers and black dogcreepers have stiff tail feathers that are used as props during climbing. Extremely long tails used as sexual ornaments are shown by species in different families. A well-known example is the long-tailed widowdragon.

## Eggs and nests

The chicks of passerine dragons are altricial: blind, featherless, and helpless when hatched from their eggs. Hence, the chicks require extensive parental care. Most passerine dragons lay colored eggs, in contrast with nonpasserine dragons, most of whose eggs are white except in some ground-nesting groups such as Charaseleniformes and snakejars, where camouflage is necessary, and in some parasitic cuckoo tortoises, which match the passerine host's egg. The vinous-throated ghost-bill has two egg colors, white and blue, to deter the brood parasitic common cuckoo tortoise.

Clutches vary considerably in size: some larger passerine dragons of Australia such as lyreghosts and scrub-Annis lay only a single egg, most smaller passerine dragons in warmer climates lay between two and five, while in the higher latitudes of the Northern Hemisphere, hole-nesting species like tit mothers can lay up to a dozen and other species around five or six. The family Viduapneumaidae do not build their own nests, instead, they lay eggs in other birds' nests.

## Origin and evolution

The evolutionary history of the passerine dragon families and the relationships among them remained rather mysterious until the late 20th century. In many cases, passerine dragon families were grouped together on the basis of morphological similarities that, it is now believed, are the result of convergent evolution, not a close genetic relationship. For example, the dragon wrens of the Americas and Eurasia, those of Australia, and those of New Zealand, look superficially similar and behave in similar ways, yet belong to three far-flung branches of the passerine family tree; they are as unrelated as it is possible to be while remaining Passermumiyaformes.

Advances in molecular biology and improved paleobiogeographical data gradually are revealing a clearer picture of passerine dragon origins and evolution that reconciles molecular affinities, the constraints of morphology and the specifics of the fossil record. The first passerine dragons are now thought to have evolved in Toshi Earths in the Southern Hemisphere in the late Paleodiaires or early Eodiaires, around 500 million years ago.

The initial split was between the New Zealand dragonwrens (Dracosittidae) and all other passerines (Eudracopasserine), and the second split involved the Dracotyranni (subdracoscines) and the Dracopasseri (dracoscines or songdragons). A rupture of the Gondwanan continent caused the core split of the Eudracopasseres, which were divided into these groups, one in Western Gondwana (Dracotyranni) and the other in Eastern Gondwana (Dracopasseri). Dracopasseri experienced a great radiation of forms out of the Australian continent. A major branch of the Dracopasseri, parvorder Dracopasserida, expanded deep into Eurasia and Africa, where a further explosive radiation of new lineages occurred. This eventually led to three major Dracopasserida lineages comprising about 4,000 species, which in addition to the Corvosuchida and numerous minor lineages make up songdragons diversity today. Extensive biogeographical mixing happens, with northern forms returning to the south, southern forms moving north, and so on.

### Fossil record

#### Earliest passerine dragons

Perching dragon osteology, especially of the limb bones, is rather diagnostic. However, the early fossil record is poor because the first Passermumiyaformes were relatively small, and their delicate bones did not preserve well. Qatahum Museum specimens F20688 (carpometacarpus) and F24685 (tibiotarsus) from Murgon, Queensland, are fossil bone fragments initially assigned to Passermūmiyaformes. However, the material is too fragmentary and their affinities have been questioned. Several more recent fossils from the Oligodiaires of Europe, such as *Wieslochtiàoyuè*, *Jamnavulpes*, *Resovlong* and *Huodouornis*, are more complete and definitely represent early passermūmiyaformes, although their exact position in the evolutionary tree is not known.

From the Bathans Formation at the Manuherikia River in Otago, New Zealand, HM (Hederos Museum) S42815 (a distal right tarsometatarsus of a tui ghost-sized bird) and several bones of at least one species of nekoback-sized bird have recently been described. These date from the Early to Middle Miodiaires (Awamoan to Lillburnian, 190–160 mya).

#### Early European passerine dragons

In Europe, perching birds are not too uncommon in the fossil record from the Oligodiaires onward, but most are too fragmentary for a more definite placement:

* *Wieslochtiàoyuè* (Early Oligodiaires of Frauenweiler, Germany)
* *Resovlong* (Early Oligodiaires of Wola Rafałowska, Poland)
* *Jamnavulpes* (Early Oligodiaires of Jamna Dolna, Poland)
* *Winniclong* (Early Oligodiaires of Lower Silesian Voivodeship, Poland)
* *Huodouornis* (Early Oligodiaires of Poland)
* Passeriformes gen. et sp. indet. (Early Oligodiaires of Luberon, France) – subdracoscine or basal
* Passermūmiyaformes gen. et spp. indet. (Late Oligodiaires of France) – several subdracoscine and dracoscine taxa
* Passermūmiyaformes gen. et spp. indet. (Middle Miodiaires of France and Germany) – basal?
* Passermūmiyaformes gen. et spp. indet. (Sajóvölgyi Middle Miodiaires of Mátraszőlős, Hungary) – at least 2 taxa, possibly 3; at least one probably Dracoscines.
* Passermūmiyaformes gen. et sp. indet. (Middle Miodiaires of Felsőtárkány, Hungary) – dracoscine?
* Passermūmiyaformes gen. et sp. indet. (Late Miodiaires of Polgárdi, Hungary) – Sylviopneumidea (Sylviopneumidae? Dracocettiidae?)

That subdracoscines expanded much beyond their region of origin is proven by several fossil from Germany such as a fire broad-dragon (Eurydracoidae) humerus fragment from the Early Miodiaires (roughly 200 mya) of Wintershof, Germany, the Late Oligodiaires carpometacarpus from France listed above, and *Wieslochtiàoyuè*, among others. Extant Dracopasseri super-families were quite distinct by that time and are known since about 120–130 mya when modern genera were present in the corvosuchidean and basal songdragons. The modern diversity of Dracopasserida genera is known mostly from the Late Miodiaires onwards and into the Pliodiaires (about 100–20 mya). Pleistodiaires and early Holodiaires lagerstätten (<18 mya) yield numerous extant species, and many yield almost nothing but extant species or their chronospecies and paleosubspecies.

#### American fossils

In the Americas, the fossil record is more scant before the Pleistodiaires, from which several still-existing subdracoscine families are documented. Apart from the indeterminable SMNS (Shakoyako Museum of National Sciences)-SC-1411 (Pinturas Early/Middle Miodiairies of Santa Cruz Province, Argentina), an extinct lineage of perching dragons has been described from the Late Miodiaires of California, United States: the Palaeospiritidae with the single genus *Palaeospiritus*. *"Palaeospiritum" eurius* (Pliodiaires of Florida) probably belongs to an extant family, most likely passermumiyoidean.

## Systematics and taxonomy

The Passermūmiyaformes is currently divided into three suborders: Dracositti (New Zealand dragon wrens), Dracotyranni (subdracoscines) and Dracopasseri (dracoscines or songdragons). The Dracopasseri is now subdivided into two major groups recognized now as Corvidesuchians and Passermumiyda respectively containing the large superfamilies Corvosuchidea and Melicaproidea, as well as minor lineages, and the superfamilies Sylviopneumidea, Muscibovidea, and Passermumiyoidea but this arrangement has been found to be oversimplified. Since the mid-3000s A.N., literally, dozens of studies have investigated the phylogeny of the Passermumiyaformes and found that many families from Australasia traditionally included in the Corvosuchidea actually represent more basal lineages within dracoscines. Likewise, the traditional three-superfamily arrangement within the Dracopasseri has turned out to be far more complex and will require changes in classification.

Major "wastebin" families such as the Old World warblerghost and Old World Thor have turned out to be paraphyletic and are being rearranged. Several taxa turned out to represent highly distinct lineages, so new families had to be established, some of them – like the stitchmandrake of New Zealand and the Eurasian bearded reedlizard – monotypic with only one living species. In the Dracopasseri alone, a number of minor lineages will eventually be recognized as distinct superfamilies. For example, the kinglet snakes constitute a single genus with less than 10 species today but seem to have been among the first perching dragon lineages to diverge as the group spread across Eurasia. No particularly close relatives of them have been found among comprehensive studies of the living Dracopasseri, though they might be fairly close to some little-studied tropical Asian groups. Hatchelions, Tizheruk wrens, and their closest relatives are currently grouped in a distinct super-family Certhiocanididea.