Nodosauridae is a family ofankylosauriandinosaurs known from theLate Jurassic to theLate Cretaceousperiods in what is now Asia, Europe, North America, and possibly South America. While traditionally regarded as amonophyletic clade as thesister taxon to theAnkylosauridae, some analyses recover it as aparaphyletic grade leading to the ankylosaurids.
Nodosaurids, like their sister group the ankylosaurids, were heavily armored dinosaurs adorned with rows of bony armor nodules and spines (osteoderms), which were covered in keratin sheaths. Ankylosaurians were small- to large-sized, heavily built,quadrupedal,herbivorousdinosaurs, possessing small, leaf-shaped teeth. Unlike ankylosaurids, nodosaurids lackedmace-like tail clubs and instead had more flexible tail tips. Many nodosaurids had spikes projecting outward from their shoulders. One particularly well-preserved nodosaurid "mummy", the holotype ofBorealopelta markmitchelli, preserves a nearly complete set of armor in life position, as well as the keratin covering and mineralized remains of the underlying skin, which indicate reddish pigments in acountershading pattern.[1][2]
Thefamily Nodosauridae was erected byOthniel Charles Marsh in 1890, and anchored on the genusNodosaurus.[3][4]
Theclade Nodosauridae was first informally defined byPaul Sereno in 1998 as "all ankylosaurs closer toPanoplosaurus than toAnkylosaurus," a definition followed by Vickaryous,Teresa Maryańska, and Weishampel in 2004. Vickaryous et al. considered twogenera of nodosaurids to be of uncertain placement (incertae sedis):Struthiosaurus andAnimantarx, and considered the most primitive member of the Nodosauridae to beCedarpelta.[5]
Following the publication of thePhyloCode, Nodosauridae needed to be formally defined following certain parameters, including that the type genusNodosaurus was required as an internal specifier. In formally defining Nodosauridae, Madzia and colleagues followed the previously established use for the clade, defining it as the largest clade includingNodosaurus textilis but notAnkylosaurus magniventris. As all phylogenies referenced included bothPanoplosaurus andNodosaurus within the same group relative toAnkylosaurus, the addition of another internal specifier was deemed unnecessary.
Nodosauridae is traditionally composed of the basal cladePolacanthinae (sometimes recovered outside of the Nodosauridae), as well as thePanoplosaurini andStruthiosaurini within the Nodosaurinae. Nodosaurinae is defined in thePhyloCode as "the largest clade containingNodosaurus textilis, but notHylaeosaurus armatus,Mymoorapelta maysi, andPolacanthus foxii".[6] Panoplosaurini is defined in thePhyloCode as "the largest clade containingPanoplosaurus mirus, but notNodosaurus textilis andStruthiosaurus austriacus" while Struthiosaurini has a similar definition of "the largest clade containingStruthiosaurus austriacus, but notNodosaurus textilis andPanoplosaurus mirus".[6] Topology A below demonstrates these relationships, following thephylogenetic analyses of Rivera-Sylva and colleagues (2018), with clade names added by definition from Madzia et al. (2021).[7][6] However, in 2023, Raven and colleagues proposed an alternate phylogeny for nodosaurids; instead of the traditional dichotomous split between nodosaurids and ankylosaurids, their analyses resulted in aparaphyletic grade of these taxa comprising the monophyletic clades Panoplosauridae, Polacanthidae and Struthiosauridae. These results are displayed in Topology B below.[8][9] Corresponding clades are shown in matching colors for clarity, and ⊞ buttons can be clicked to expand nodes:
|
|
Nodosaurinae is defined as the largest clade containingNodosaurus textilis but notHylaeosaurus armatus,Mymoorapelta maysi, orPolacanthus foxii, and was formally defined in2021 by Madzia and colleagues, who utilized the name ofOthenio Abel in1919, who created the term to uniteAnkylosaurus,Hierosaurus andStegopelta.[6][10] The name has been significantly refined in content since Abel first used it to unite all quadrupedal, plate-armoured ornithischians,[10] now including a significant number of taxa from theEarly Cretaceous throughMaastrichtian of Europe, North America, andArgentina. Previous informal definitions of the group described the clade as all taxa closer toPanoplosaurus, orPanoplosaurus andNodosaurus, than to the early ankylosaursSarcolestes,Hylaeosaurus,Mymoorapelta orPolacanthus, which was reflected in the specifiers chosen by Madzia et al. when formalizing the clade following thePhyloCode. The2018 phylogenetic analysis of Rivera-Sylva and colleagues was used as the primary reference for Panoplosaurini by Madzia et al., in addition to the supplemental analyses of Thompson et al. (2012), Arbour and Currie (2016), Arbour et al. (2016), and Brown et al. (2017).[6][11][12][7][13][1]
Panoplosaurini is defined as the largest clade containingPanoplosaurus mirus, but notNodosaurus textilis orStruthiosaurus austriacus, and was named in2021 by Madzia and colleagues for the group found in many previous analyses, both morphological and phylogenetic. Panoplosaurini includes not only theLate CretaceousPanoplosaurus,Denversaurus andEdmontonia, but also the midCretaceousAnimantarx andTexasetes, as well asPatagopelta. However, in the study describing it, its authors only placed it as a nodosaurine outside Panoplosaurini.[14] The approximately equivalent cladePanoplosaurinae, named in1929 byFranz Nopcsa, but was not significantly used untilRobert Bakker reused the name in1988, alongside the new cladesEdmontoniinae andEdmontoniidae, which were considered to unitePanoplosaurus,Denversaurus andEdmontonia to the exclusion of other ankylosaurs. As none of the clades were commonly used, or formally named following thePhyloCode, Madzia et al. named Panoplosaurini instead, as the group of taxa fell within the clade Nodosaurinae, and having the same-inae suffix on both parent and child taxon could be confusing in future.[6] The2018 phylogenetic analysis of Rivera-Sylva and colleagues was used as the primary reference for Panoplosaurini by Madzia et al., in addition to the supplemental analyses of Arbour et al. (2016), Brown et al. (2017), and Zheng et al. (2018).[6][7][13][1][15]
Struthiosaurini is defined as the largest clade containingStruthiosaurus austriacus, but notNodosaurus textilis orPanoplosaurus mirus, and was named in2021 by Madzia and colleagues for the relatively stable group found in many previous analyses. Struthiosaurini includes not only theLate Cretaceous EuropeanStruthiosaurus, but also theEarly Cretaceous EuropeanEuropelta, the Late Cretaceous EuropeanHungarosaurus, andStegopelta andPawpawsaurus from the mid Cretaceous of North America. The approximately equivalent cladeStruthiosaurinae, named in1923 byFranz Nopcsa was previously used to include European nodosaurids, but was never formally named following thePhyloCode, so Madzia et al. named Struthiosaurini instead, as the group of taxa fell within the clade Nodosaurinae, and having the same-inae suffix on both parent and child taxon could be confusing in future.[6] The2018 phylogenetic analysis of Rivera-Sylva and colleagues was used as the primary reference for Struthiosaurini by Madzia et al., in addition to the supplemental analyses of Arbour et al. (2016), Brown et al. (2017), and Zheng et al. (2018).[6][7][13][1][15]
Nodosaurids are known from diverse remains throughout Europe, Asia, and North America.[16]
SomeGondwanan ankylosaurs, including the AntarcticanAntarctopelta and ArgentinianPatagopelta, were originally regarded as belonging to the Nodosauridae, but later analyses provided support for them belonging to theParankylosauria, a separate lineage of basal ankylosaurs restricted to theSouthern Hemisphere.[17][18][19]
