Gnathosaurus

{{short description|Genus of ctenochasmatid pterosaur from the Late Jurassic period}}

{{Automatic taxobox

| fossil_range = Late Jurassic,
{{fossilrange|Tithonian|latest=139}}

| image = Gnathosaurus skull.jpg

| image_caption = Fossil skull referred to G. subulatus

| taxon = Gnathosaurus

| authority = Meyer, 1833

| type_species_authority = Meyer, 1833

| type_species = {{extinct}}Gnathosaurus subulatus

| subdivision_ranks = Other species

| subdivision = *{{extinct}}G. macrurus
(Seeley, 1869)

| synonyms = Synonyms of G. macrurus:

Pterodactylus macrurus
Seeley, 1869

Synonyms of G. subulatus:{{Cite journal|last=Bennett |first=S. C. |year=2025 |title=A review of the pterosaur Gnathosaurus subulatus from the Tithonian Solnhofen Lithographic Limestones of Germany: taxonomy and ontogeny |journal=Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen |doi=10.1127/njgpa/2025/1245 }}

Pterodactylus micronyx?
Meyer, 1856
Aurorazhdarcho primordius?
Frey et al., 2011

}}

Gnathosaurus (meaning "jawed lizard") is a genus of ctenochasmatid pterosaur containing two species: G. subulatus, named in 1833 from the Solnhofen Limestone of Germany, and G. macrurus, known from the Purbeck Limestone of the UK. Its fossil remains dated back to the Late Jurassic period.

History of discovery

File:Ctenochasmatid jaws.png jaws; A is Gnathosaurus]]

Fragments of Gnathosaurus jaws were first discovered in 1832 in the Solnhofen limestones of southern Germany but were mistaken for a piece of teleosaurid crocodile jaw by Georg zu Münster, who first named the species Crocodilus multidens in that year. Soon afterwards, Hermann von Meyer classified the same specimen as the new genus and species Gnathosaurus subulatus, a name which came to be universally used shortly thereafter. In the 1860s, scientists such as Albert Oppel compared the G. subulatus jaw fragment to contemporary pterosaurs such as Pterodactylus and Ctenochasma, and concluded that it was also probably a "flying reptile" rather than a crocodilian.Oppel, A. (1862). Paleontologische Mittheilungen aus dem museum der Koenigl, Paleontologische Mittheilungen aus dem museum der Koenigl. Ebner & Seubert. A more complete skull of an adult pterosaur was found in 1951 and classified as Gnathosaurus subulatus. This slender, {{convert|28|cm|in|sp=us}} long skull had up to 130 needle-like teeth arranged around the side of a spoon-shaped tip. The specimen had an estimated wingspan of about {{convert|1.7|m|ft|sp=us}}. It probably lead a lifestyle akin to that of modern spoonbills, wading with its jaws open and closing them upon touching small prey.Wilton, Mark P. (2013). Pterosaurs: Natural History, Evolution, Anatomy. Princeton University Press. {{ISBN|0691150613}}.

Possible juvenile specimens of G. subulatus may be known from several complete skeletons that had previously been classified as the separate species Pterodactylus micronyx.{{cite journal | last1 = Bennett | first1 = S.C. | year = 2002 | title = Soft tissue preservation of the cranial crest of the pterosaur Germanodactylus from Solnhofen | journal = Journal of Vertebrate Paleontology | volume = 22 | issue = 1| pages = 43–48 | doi = 10.1671/0272-4634(2002)022[0043:stpotc]2.0.co;2 | s2cid = 86308635 }} These specimens have also been referred to the genus Aurorazhdarcho, which may itself be a synonym of Gnathosaurus. Gnathosaurus subulatus is currently known only from skulls and jaws, and adult Aurorazhdarcho micronyx is known only from a skeleton lacking a skull, making direct comparisons difficult.{{cite journal |author=S. Christopher Bennett |year=2013 |title=New information on body size and cranial display structures of Pterodactylus antiquus, with a revision of the genus |journal=Paläontologische Zeitschrift |volume=87 |issue=2 |pages=269–289 |doi=10.1007/s12542-012-0159-8 |s2cid=83722829 }} Furthermore, in the only cladistic analysis to date that tests the relationships of both taxa they are found distinct.{{Cite journal | doi = 10.1371/journal.pone.0110646| title = Pterodactylus scolopaciceps Meyer, 1860 (Pterosauria, Pterodactyloidea) from the Upper Jurassic of Bavaria, Germany: The Problem of Cryptic Pterosaur Taxa in Early Ontogeny| journal = PLOS ONE| volume = 9| issue = 10| pages = e110646| year = 2014| last1 = Vidovic | first1 = S. U. | last2 = Martill | first2 = D. M. | pmc = 4206445 | pmid = 25337830| bibcode = 2014PLoSO...9k0646V| doi-access = free}} However, Bennett (2025) compared fossil material of Gnathosaurus subulatus with skulls of the largest juvenile specimens of Aurorazhdarcho micronyx, and concluded that Aurorazhdarcho micronyx is indeed a junior synonym of Gnathosaurus subulatus.

An additional large specimen, originally named Pterodactylus macrurus, is known from the Purbeck Limestone formation of England. Represented only by a partial lower jaw and neck vertebrae, it has since been considered closer to Gnathosaurus, and its binomial changed to G. macrurus.Howse S. C. B. and Milner A. R., 1995, The Pterodactyloids from the Purbeck Limestone Formation of Dorset. Bull. Nat. Hist. Mus. London. (Geol) 51(1): 73-88.

Classification

File:Dakosaurus2.jpg]]

Below is cladogram following a topology by Sita Manitkoon and colleagues in a 2025 study; it finds Gnathosaurus to be most closely related to the genus Tacuadactylus.{{cite journal | url=https://www.sciencedirect.com/science/article/pii/S0195667125000588 | title=First gnathosaurine (Pterosauria, Pterodactyloidea) from the Early Cretaceous of eastern Thailand | journal=Cretaceous Research | last1=Manitkoon | first1=Sita | last2=Pêgas | first2=Rodrigo V. | last3=Nonsrirach | first3=Thanit | last4=Warapeang | first4=Prapasiri | last5=Lauprasert | first5=Komsorn | last6=Deesri | first6=Uthumporn | last7=Tumpeesuwan | first7=Sakboworn | last8=Wongko | first8=Kamonlak | last9=Zhou | first9=Xuanyu | year=2025 | doi=10.1016/j.cretres.2025.106135| url-access=subscription }}

{{clade| style=font-size:90%;line-height:90%

|label1=Ctenochasmatidae

|1={{clade

|1=Huanhepterus

|2={{clade

|1=Aurorazhdarcho

|2=Ardeadactylus }} }}

|2={{clade

|1={{clade

|1=Elanodactylus

|2=Forfexopterus }}

|2={{clade