Sphenodraco

{{Short description|Genus of extinct reptiles}} {{Speciesbox | fossil_range = Late Jurassic, {{fossilrange|Tithonian|Tithonian|early Tithonian}} | image = Sphenodraco.jpg | image_upright = 0.5 | image_caption = Photo of the holotype counterslab (NHMUK PV R 2741) | display_parents = 2 | genus = Sphenodraco | parent_authority = Beccari et al., 2025 | species = scandentis | authority = Beccari et al., 2025 }} {{External media | width = 266px | float = right | image1 = [https://academic.oup.com/view-large/figure/535462578/zlaf073_fig16.jpg Life restoration by Gabriel Ugueto:] ''Sphenodraco'' in the Solnhofen palaeoenvironment. }} '''''Sphenodraco''''' (meaning "sphenodontian dragon") is an extinct genus of neosphenodontian reptiles known from the Late Jurassic (Tithonian age) Altmühltal Formation, part of the Solnhofen Archipelago in Germany. The genus contains a single species, '''''Sphenodraco scandentis''''', known from a nearly complete skeleton preserved on a slab and counterslab. The elongated proportions of its limbs are similar to those of living arboreal lizards. As such, ''Sphenodraco'' may be the first known fully tree-dwelling rhynchocephalian.<ref name="Sphenodraco">{{Cite journal |last1=Beccari |first1=Victor |last2=Guillaume |first2=Alexandre R. D. |last3=Jones |first3=Marc E. H. |last4=Villa |first4=Andrea |last5=Cooper |first5=Natalie |last6=Regnault |first6=Sophie |last7=Rauhut |first7=Oliver W. M. |date=2025-07-01 |title=An arboreal rhynchocephalian from the Late Jurassic of Germany, and the importance of the appendicular skeleton for ecomorphology in lepidosaurs |journal=Zoological Journal of the Linnean Society |volume=204 |issue=3 |article-number=zlaf073 |doi=10.1093/zoolinnean/zlaf073 |issn=0024-4082|doi-access=free |hdl=10362/186782 |hdl-access=free }}</ref>

== Discovery and naming == ''Sphenodraco'' is known from a single articulated, nearly complete specimen preserved in ventral view (seen from the bottom) on two separate slabs (a part and counterpart). It was discovered in outcrops of the Altmühltal Formation (likely the Upper Eichstätt Member) near Eichstätt, Germany. Surprisingly—and for unknown reasons—these two slabs are housed separately in different institutions. The main slab, accessioned at the Naturmuseum Senckenberg in Germany as specimen SMF R414, comprises a natural mold of the skeleton with some of the bone. It was first figured in 1931 and later reported in 1963 as belonging to the species ''Homoeosaurus maximiliani''.<ref name="C-M1963">{{Cite journal |last1=Cocude-Michel |first1=Marguerite |date=1963 |title=Les rhynchocéphales et les sauriens des calcaires lithographiques (Jurassique supérieur) d'Europe occidentale |url=https://www.persee.fr/doc/mhnly_0373-6636_1963_num_7_1_992 |journal=Nouvelles archives du Muséum d'histoire naturelle de Lyon |language=fr |volume=7 |issue=1 |pages=3–224 |doi=10.3406/mhnly.1963.992 |issn=0373-6636}}</ref> The counterslab, housed at the Natural History Museum in London, England, as specimen NHMUK PV R 2741, contains most of the skeletal material. This part of the specimen had not been previously reported or described. In 2022, the counterslab was 'rediscovered' and identified as belonging to the same individual as SMF R414.<ref name="Sphenodraco" />

In a 2025 publication, Victor Beccari and colleagues recognized several anatomical characters distinguishing these specimens from ''Homoeosaurus''. As such, they described ''Sphenodraco scandentis'' as a new genus and species of rhynchocephalians based on these fossil remains. The generic name, ''Sphenodraco'', combines the prefix ''spheno-''—derived from the Ancient Greek σφήν (''sphḗn''), meaning "wedge"<ref name="MW">{{Cite Merriam-Webster|sphen-|access-date=2025-07-02}}</ref>—with the Latin word ''draco'', meaning "dragon". The name references both the Sphenodontia—the clade to which it belongs—and the gliding abilities of the arboreal lizards to which its limb proportions are comparable. The specific name, ''scandentis'', derived from ''scandens'', a Latin word meaning "climber".<ref name="Sphenodraco" />

== Classification == thumb|Fossil of ''Homoeosaurus maximilliani'', a closely related species that ''Sphenodraco'' was once thought to belong to In their phylogenetic analyses (most parsimonious tree, implied weighting), Beccari and colleagues (2025) recovered ''Sphenodraco'' as a member of the rhynchocephalian clade Neosphenodontia, as the sister taxon to ''Kallimodon'' spp. in a clade also including ''Homoeosaurus'' spp. These results are displayed in the simplified cladogram below:<ref name="Sphenodraco" />{{clade|{{clade |1=†''Gephyrosaurus'' |label2='''Sphenodontia''' |2={{clade |1=†''Diphydontosaurus'' |2={{clade |1=†''Planocephalosaurus'' |label2='''Eusphenodontia''' |2={{clade |1=†''Clevosaurus'' (paraphyletic) |label2='''Neosphenodontia''' |2={{clade |label1=Sphenodontidae |1={{clade |label1=†Eilenodontinae |1={{clade |1=†''Priosphenodon'' |2=†''Sphenotitan'' }} |label2=Sphenodontinae |2={{clade |1=†''Opisthiamimus'' |2={{clade |1=†''Navajosphenodon'' |2={{clade |1=†''Sphenofontis'' |2=''Sphenodon'' (tuatara) }}}}}}}} |2={{clade |1=†''Homoeosaurus solnhofensis'' |2={{clade |1={{clade |1={{clade |1=†''Homoeosaurus maximiliani'' |2=†''Homoeosaurus parvipes'' }} |2={{clade |1=†''Sphenodraco'' |2=†''Kallimodon'' }} }} |2={{clade |label1=†Pleurosauridae |1={{clade |1=†''Derasmosaurus'' |2={{clade |1=†''Ankylosphenodon'' |2={{clade |1=†''Palaeopleurosaurus'' |2={{clade |1=†''Acrosaurus'' |2=†''Pleurosaurus'' }}}}}}}} |2={{clade |1=†''Vadasaurus'' |label2=†Sapheosauridae |2={{clade |1=†''Sapheosaurus'' |2={{clade |1=†''Piocormus'' |2=†''Oenosaurus'' }}}}}}}}}}}}}}}}}}}}}}|label1=Rhynchocephalia}}

In a 2026 description of the axial skeleton of the modern tuatara (''Sphenodon punctatus''), Beccari and colleagues incorporated 16 new phylogenetic characters into their previous dataset based on their observations of this anatomical region. As in their 2025 analysis, ''Sphenodraco'' was recovered in a clade also containing ''Kallimodon'' and ''Homoeosaurus'', in addition to SNSB-BSPG 1993 XVIII 3, an unnamed specimen from the Brunn locality of the Solnhofen Archipelago.<ref name="Beccari2026">{{Cite journal |last1=Beccari |first1=Victor |last2=Jones |first2=Marc E. H. |last3=Villa |first3=Andrea |last4=Martino |first4=Roberta |last5=Regnault |first5=Sophie |last6=Glaw |first6=Frank |last7=Rauhut |first7=Oliver W. M. |date=2026-04-01 |title=The axial skeleton of the tuatara (Rhynchocephalia: ''Sphenodon''): insights on intraspecific variability, ontogeny, sexual dimorphism, and remarks on fossil taxa |url=https://academic.oup.com/zoolinnean/article/206/4/zlaf135/8570147 |journal=Zoological Journal of the Linnean Society |volume=206 |issue=4 |article-number=zlaf135 |doi=10.1093/zoolinnean/zlaf135 |doi-access=free|url-access=subscription }}</ref>

== References == {{Reflist}}

Category:Rhynchocephalia Category:Jurassic lepidosaurs Category:Solnhofen fauna Category:Tithonian genera Category:Late Jurassic reptiles of Europe Category:Prehistoric reptile genera Category:Fossil taxa described in 2025