| Lonchodraco | |
|---|---|
 | |
| Lectotype ofL. giganteus | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | †Pterosauria |
| Suborder: | †Pterodactyloidea |
| Family: | †Lonchodraconidae |
| Genus: | †Lonchodraco Rodrigues & Kellner,2013 |
| Type species | |
| †Pterodactylus giganteus Bowerbank, 1846 | |
| Species | |
| Synonyms | |
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Lonchodraco is agenus oflonchodraconidpterodactyloidpterosaur from the LateCretaceous of southernEngland. The genus includes species that were previously assigned to other genera.[1]
In 1846,James Scott Bowerbank named and described some remains found in a chalk pit atBurham nearMaidstone inKent, as a new species ofPterodactylus:Pterodactylus giganteus. Thespecific name means "the gigantic one" inLatin.[2] The same pit generated remains ofPterodactylus cuvieri.[3] In 1848, Bowerbank published ahistological study of the bone structure ofP. giganteus.[4]
At the time, theBritish Association Code of 1843 allowed to change names if they were inappropriate. In 1850,Richard Owen, considering the species not to have been particularly large, and renamed it intoPterodactylus conirostris; the specific name meaning "cone-snouted", which was based on the conical snout of specimen NHMUK PV 39412.[5] However, after insistent objections by Bowerbank, Owen retracted this name in 1851 when he described the finds in more detail.[6]
In 1914Reginald Walter Hooley assigned the species to a new genusLonchodectes, "the lance biter", as aLonchodectes giganteus.[7] In 2013,Taissa Rodrigues andAlexander Wilhelm Armin Kellner concluded that thetype species ofLonchodectes,Lonchodectes compressirostris, was anomen dubium. Therefore, they created a new genusLonchodraco, combining Greek λόγχη,lonchē, "lance", with Latindraco, "dragon".Pterodactylus giganteus was made the type species ofLonchodraco, resulting in aLonchodraco giganteus. Two other species previously assigned toLonchodectes were moved to the new genus, resulting in aLonchodraco machaerorhynchus and aLonchodraco(?) microdon. The question mark in the latter name indicates that the authors were uncertain about the correctness of the assignment.[1]
Rodrigues and Kellner consideredNHMUK PV 39412 to be thelectotype ofLonchodraco giganteus, after a choice byPeter Wellnhofer in 1978.[8] It was found in a layer of theChalk Formation, dating from theCenomanian-Turonian. It consists of the front of a snout, the front of a pair of lower jaws, a piece of ascapulocoracoid, the upper parts of a humerus and an ulna, and a part of a wing finger phalanx.[1]
Also in 1869, Seeley informally named "Ptenodactylus microdon".[9] In 1870, he formally named itOrnithocheirus microdon, "small tooth",[10] Hooley (1914) transferred this species toLonchodectes to form the new combinationLonchodectes microdon.[7] Its holotype, CAMSM B54486, has its provenance in the Cambridge Greensand and consists of the front of a snout. The type specimen ofOrnithocheirus oweni Seeley 1870, CAMSM B 54439, was synonymized withmicrodon by Unwin (2001),[11] and Rodrigues & Kellner (2013) agreed with this synonymy.[1]
In 1869,Harry Govier Seeley namedPtenodactylus machaerorhynchus,[9] at the same time disclaiming the name which makes it invalid by modern standards. In 1870, Seeley had realised that the generic namePtenodactylus had been preoccupied and renamed the species intoOrnithocheirus machaerorhynchus.[10] The specific name means "sabre snout" in Greek. In 1914 Hooley renamed it intoLonchodectes machae[r]orhynchus.[7] Its holotype, CAMSM B54855, was nearCambridge found 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.[1] However, in his review of Lonchodectidae, Averianov (2020) assignedLonchodraco machaerorhynchus toIkrandraco due to similarities in rostral morphology, asI. machaerorhynchus, and he also declaredLonchodraco microdon (includingP. oweni) a junior synonym ofmachaerorhynchus. Thus,Lonchodraco is limited to the type speciesL. giganteus.[12]
Rodrigues & Kellner treatedLonchodraco as aclade, which thus could possesssynapomorphies, shared derived traits, setting the clade apart from related groups. They established one of these: the tooth sockets are elevated relative to the palate and lower jaw edge. Also a unique combination of themselves not unique traits was present. The tooth sockets in the front of the jaws are small, with a diameter of no more than four millimetres. These sockets do not vary significantly in size. The distance between the tooth sockets about equals their diameter. The midline ridge on the palate is high. A crest is present below the lower jaws.[1]
Bowerbank estimatedP. giganteus had awingspan of about eight to nine feet. Rodrigues & Kellner established two autapomorphies ofLonchodraco giganteus. Below the front of the lower jaws a short blade-like crest is present. There is a density of about six tooth sockets per three centimetres of jaw edge. There is a unique combination of traits: the snout bears a crest; the front part of the snout is rounded; the front part of the lower jaws is rounded; the margins of the front tooth sockets diverge.[1]
In 2013, Brazilian paleontologists Rodrigues & Kellner assignedLonchodraco to a family calledLonchodraconidae, which was not defined as a clade and of whichLonchodraco was the only member. Later in their analysis however, Rodrigues & Kellner considered the definition of Lonchodraconidae to be more or less synonymous to that ofLonchodectidae, however, they stated thatLonchodectes is anomen dubium and therefore should not be included in the group. In theircladistic analysis, they concluded that the three species ofLonchodraco formed a cluster, but it proved impossible to obtain a precise position for it because their inclusion in the dataset made the tree largely collapse into apolytomy containing, apart from the three species, all Pterodactyloidea and even theRhamphorhynchidae.[1]
A topology recovered by Longrich and colleagues in 2018 placedLonchodraco within the family Lonchodectidae as the sister taxon ofLonchodectes, with the family being placed within the larger groupOrnithocheiromorpha.[13] However, in several recent studies, including Pêgaset al. (2019) and Holgado & Pêgas (2020), the term Lonchodraconidae is used, andLonchodraco is recovered within this group, sister taxon toIkrandraco.[14][15]
Topology 1: Longrichet al. (2018). | Topology 2: Pêgaset al. (2019).
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