| Ikrandraco | |
|---|---|
 | |
| I. avatarholotype,Paleozoological Museum of China | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | †Pterosauria |
| Suborder: | †Pterodactyloidea |
| Clade: | †Ornithocheiromorpha |
| Clade: | †Lanceodontia |
| Family: | †Lonchodraconidae |
| Genus: | †Ikrandraco Wanget al., 2020 |
| Type species | |
| †Ikrandraco avatar Wanget al., 2020 | |
| Other species | |
| Synonyms | |
Synonyms ofI. machaerorhynchus
| |
Ikrandraco ("Ikran [a flying creature fromAvatar with a crest on the lower jaw] dragon") is agenus oflonchodraconidpterodactyloidpterosaur known from theLower CretaceousJiufotang Formation of northeasternChina, and theCambridge Greensand ofEngland. It is notable for its unusual skull, which features a crest on the lower jaw.
Thetype species,Ikrandraco avatar isbased on specimenIVPP V18199, a partial skeleton including the skull and jaws, severalneckvertebrae, a partialsternal plate, parts of both wings, and part of a foot. A second specimen, IVPP 18406, has also been assigned toIkrandraco; it consists of a skull and jaws and the first three neck vertebrae. Both specimens come from theAptian-age Lower CretaceousJiufotang Formation ofLiaoning, with an estimated date of 120 million years ago. The type species isI. avatar, a second reference to James Cameron’s “Avatar”. It was described in2014 by Wang Xiaolin and colleagues,[1] but was not properly named according to ICZN rules until 2020.[2]
In 1869, British paleontologistHarry Govier Seeley assigned remains he found to a new species of pterosaur calledPtenodactylus machaerorhynchus,[3][4] at the same time disclaiming the name which makes it invalid by modern standards. In 1870, Seeley had realized that the generic namePtenodactylus had been preoccupied and renamed the species intoOrnithocheirus machaerorhynchus.[5] The specific name means "sabre snout" in Greek. In 1914, Hooley renamed it intoLonchodectes machaerorhynchus.[6] Its holotype, CAMSM B54855, was found nearCambridge, in a layer of theCambridge Greensand dating from the Cenomanian but containing reworked fossils from theAlbian. It consists of the rear end of asymphysis of the lower jaws.[4]
Also in 1869, Seeley informally named "Ptenodactylus microdon".[3] In 1870, he formally named itOrnithocheirus microdon, "small tooth",[5] Hooley (1914) transferred this species toLonchodectes to form the new combinationLonchodectes microdon.[6] Its holotype, CAMSM B54486, has its provenance in the Cambridge Greensand and consists of the front of a snout. The type specimen of the speciesOrnithocheirus oweni, CAMSM B 54439, initially described by Seeley in 1864 asPterodactylus oweni, was synonymized withmicrodon by Unwin in 2001,[7] and later in 2013, Rodrigues & Kellner agreed with this synonymy.[4]
In 2013, paleontologistsTaissa Rodrigues andAlexander Kellner made an extensive review of the species ofOrnithocheirus, and stated that the generic nameLonchodectes would have been anomen dubium, and therefore reassigned bothLonchodectes machaerorhynchus andL. microdon into the genusLonchodraco, creatingLonchodraco machaerorhynchus andL. microdon.[4]
In his review of Lonchodectidae,Alexander Averianov reassignedLonchodraco machaerorhynchus toIkrandraco, and also declaredLonchodraco microdon (includingO. oweni) a junior synonym ofmachaerorhynchus.[8]
Ikrandraco avatar is notable for having a very long, low skull (the height of the back of the skull, at thequadrates, is less than 19% the length of the skull), with a prominent blade-like crest on the underside of the lower jaw and no corresponding crest on the tip of the upper jaw, a crest combination not seen in other pterosaurs to date. Theposterior edge of the crest also has a hook-like process. Each side of the upper jaw has at least 21 small cylindrical teeth, and each side of the lower jaw has at least 19. The skull of the type specimen is 286.5 millimeters (11.28 in) long, and the skull of the second specimen is at least 268.3 millimeters (10.56 in) long.[1]
Rodrigues & Kellner established four autapomorphies ofIkrandraco machaerorhynchus (thenLonchodraco). A deep crest is present at the underside of the lower jaws. To the rear, the profile of this crest turns upwards. Behind this crest a depression is present at the underside of the jaws. The midline groove at the top of the lower jaws symphysis is deep. Furthermore, there is a density of 4.5 teeth per three centimeters of jaw edge.[4]
Wanget al. performed aphylogenetic analysis includingIkrandraco and found it to be abasal pteranodontoid, morederived thanPteranodon but not as derived as theistiodactylids,anhanguerids, and other pteranodontoids.[1] The portion of their results dealing with Pteranodontoidea is shown below.
The cladogram below is a topology recovered by Pêgaset al. (2019). In the analyses, they recoveredIkrandraco as a member of the familyLonchodraconidae, and the sister taxon ofLonchodraco.[9]
Wanget al. interpreted the crest as a possible adaptation for skim fishing, although they did not regard this as the animal's main method of foraging. The hook on the crest may have been an attachment point for a throat pouch for storing food, akin to apelican.Ikrandraco was an approximate contemporary of the distantly relatedanhangueriansLiaoningopterus gui andGuidraco venator, and all three are regarded aspiscivores, butIkrandraco differed from them in its much smaller and less robust teeth, indicating it had a different niche.[1]
