Monofenestrata

{{automatic taxobox

| name = Monofenestratans

| fossil_range =
Early Jurassic – Late Cretaceous, {{fossilrange|earliest=184|179|66}}

| image = Monofenestratan skull comparison.jpg

| image_caption = Several pterosaur skulls prominently displaying the eponymous single fenestra

| taxon = Monofenestrata

| authority = Lü et al., 2010

| subdivision_ranks = Subgroups

| subdivision =

{{extinct}}Archaeoistiodactylus
{{extinct}}Melkamter
{{extinct}}Darwinoptera
{{extinct}}Allkaruen?
{{extinct}}Ceoptera
{{extinct}}Pterorhynchus
{{extinct}}Wukongopteridae
{{extinct}}Pterodactyliformes
{{extinct}}Changchengopterus
{{extinct}}Douzhanopterus
{{extinct}}Propterodactylus?
{{extinct}}Skiphosoura
{{extinct}}Anurognathidae?
{{extinct}}Pterodactyloidea

}}

Monofenestrata is a clade of pterosaurs. It includes the pterosaurs in which the nasal and antorbital fenestra (openings/holes) in the skull are merged into a single fenestra. The clade includes the pterodactyloids and their close relatives.

The clade Monofenestrata was in 2010 defined as the group consisting of Pterodactylus and all species sharing with Pterodactylus the synapomorphy of an external nostril confluent with the antorbital fenestra, the major skull opening on the side of the snout. The name is derived from Greek monos, "single", and Latin fenestra, "window". The concept was inspired by the discovery of Darwinopterus, a species combining a pterodactyloid-type skull with a more basal build of the remainder of the body.{{cite journal | last1 = Lü | first1 = J. | last2 = Unwin | first2 = D.M. | last3 = Jin | first3 = X. | last4 = Liu | first4 = Y. | last5 = Ji | first5 = Q. | year = 2010 | title = Evidence for modular evolution in a long-tailed pterosaur with a pterodactyloid skull | journal = Proceedings of the Royal Society B | volume = 277 | issue = 1680| pages = 383–389 | doi = 10.1098/rspb.2009.1603 | pmid = 19828548 | pmc=2842655}} The Darwinoptera, a primitive subgroup of monofenestratans showing this transitional anatomy, was also named for Darwinopterus and defined as all descendants of its common ancestor with Pterorhynchus.{{cite journal |author1=Andres, B. |author2=Clark, J. |author3=Xu, X. |year=2014 |title=The Earliest Pterodactyloid and the Origin of the Group |journal=Current Biology |volume= 24|issue=9 |pages= 1011–6|url=https://www.cell.com/current-biology/pdfExtended/S0960-9822(14)00322-4|doi=10.1016/j.cub.2014.03.030 |pmid=24768054|doi-access=free }}

File:Melkamter_(life_restoration).jpg]]

File:Darwinopterus_NT.jpg in flight]]

The earliest known monofenestratan fossils have been found in the Stonesfield Slate formation of the United Kingdom, which dates to the Bathonian stage of the Middle Jurassic, dated to about 166 million years ago. Identified elements include cervical vertebrae, fourth metacarpals and a possible pterodactyloid synsacrum.Michael O’Sullivan; David M. Martill (2018). "Pterosauria of the Great Oolite Group (Bathonian, Middle Jurassic) of Oxfordshire and Gloucestershire, England". Acta Palaeontologica Polonica. Online edition. {{doi|10.4202/app.00490.2018}}. An earlier undescribed taxon along with the coeval and corregional Allkaruen may also belong to the group, both reported from Middle Toarcian layers of the Cañadón Asfalto Formation of Argentina.{{cite journal |last1=Codorniú |first1=L. |last2=Carabajal |first2=A.P. |last3=Pol |first3=D. |last4=Unwin |first4=D. |last5=Rauhut |first5=O.W.M |date=2016 |title=A Jurassic pterosaur from Patagonia and the origin of the pterodactyloid neurocranium |journal=PeerJ |volume=4 |pages=e2311 |doi=10.7717/peerj.2311 |pmc=5012331 |pmid=27635315 |doi-access=free}}{{Cite journal |last1=Fernandes |first1=A.E |last2=Pol |first2=D. |last3=Rauhut |first3=O.W.M. |date=2024 |title=A monofenestratan pterosaur from the late Early Jurassic of the Chubut province of Patagonia, Argentina. |url=https://www.nhm.uio.no/english/research/events/conferences/EAVP2024/eavp-abstracts-2024-volume-complete-final.pdf |journal=EAVP2024 Abstract Book and Programme |volume=21 |issue=1 |pages=18}}

Below is a cladogram showing the results of a phylogenetic analysis presented by Andres, Clark & Xu, 2014. This study found the two traditional groupings of ctenochasmatoids and kin as an early branching group (represented as the group Archaeopterodactyloidea), with all other pterodactyloids grouped into the Eupterodactyloidea.

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

|label1=Pterodactylomorpha

|1={{clade

|1=Sordes50 px

|label2=Monofenestrata

|2={{clade

|label1=Darwinoptera

|1={{clade

|1=Pterorhynchus

|2=Wukongopteridae }}

|label2=Pterodactyliformes

|2={{clade

|1=Changchengopterus

|label2=Caelidracones

|2={{clade

|1=Anurognathidae 30 px

|label2=Pterodactyloidea

|2={{clade

|1=Archaeopterodactyloidea 50 px

|2=Eupterodactyloidea 50 px

}} }} }} }} }} }}

Contrastingly, a 2024 paper by David Hone and colleagues describing the transitional taxon Skiphosoura found primitive monofenestratans to represent an evolutionary grade leading towards Pterodactyloidea, rather than a distinct darwinopteran or wukongopterid grouping. A cladogram of their results is shown below.{{Cite journal |last=Hone |first=David W. E. |last2=Fitch |first2=Adam |last3=Selzer |first3=Stefan |last4=Lauer |first4=René |last5=Lauer |first5=Bruce |date=2024-11-18 |title=A new and large monofenestratan reveals the evolutionary transition to the pterodactyloid pterosaurs |url=https://www.sciencedirect.com/science/article/pii/S0960982224013770 |journal=Current Biology |language=en |doi=10.1016/j.cub.2024.10.023 |issn=0960-9822 |doi-access=free}}

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

|label1=Monofenestrata/Darwinoptera

|1={{clade

|1=Pterorhynchus

|2={{clade

|1="Darwinopterus" robustodens

|2={{clade

|1={{clade

|1=Darwinopterus modularis

|2=Cuspicephalus }}

|label2=Pterodactyliformes

|2={{clade