The oldest Archaeopteryx (Theropoda: Avialiae): a new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, Bavaria

“Furthermore, the discovery came just two years after the publication of Darwin’s Origin of species (Darwin, 1859), and the intermediate morphology of Archaeopteryx rapidly became an important argument in favour of his theory (Huxley, 1868).”

“…in the dentition of Archaeopteryx might represent to some degree a Jurassic equivalent to the famous Darwin Finches, in which species show a great variety in the shape of their beaks, correlating with respective diet spectra (Sato et al., 2001; Abzhanov et al., 2006; Lamichhaney et al., 2015).”

“If so, the variation in the dentition of Archaeopteryx might represent to some degree a Jurassic equivalent to the famous Darwin Finches, in which species show a great variety in the shape of their beaks, correlating with respective diet spectra (Sato et al., 2001; Abzhanov et al., 2006; Lamichhaney et al., 2015).”

“The central part of the jugal is collapsed, indicating that it had a medial longitudinal furrow, as it is present in the jugal of the Munich specimen (BSPG 1999 I 50) and the 11th specimen (Foth, Tischlinger & Rauhut, 2014), and in Anchiornis (Hu et al., 2009).”

“…process of jugal; lack of mandibular fenestra; nine cervical vertebrae; intermediate process of the ischium Archaeopteryx sp. Wellnhofer (1974), Ostrom (1976), Elzanowski & Wellnhofer (1996), Howgate (1984a, 1985) 6 Solnhofen specimen Shape of premaxillary teeth; intermediate process…”

“In Bambiraptor, Xiaotingia and Anchiornis, the margin of the fenestra curves gradually from the postorbital process onto the quadratojugal process.”

“The second phalanx is slightly more slender and has a flattened ventral surface, in contrast to many dromaeosaurids (Ostrom, 1969; Rauhut & Werner, 1995; Norell & Makovicky, 1997; Forster et al., 1998; Novas et al., 2009; Turner, Makovicky & Norell, 2012) and troodontids (Currie & Peng, 1993; Zanno et al.”

“6, 7 and 9), rather than the T-shaped element seen in basal tetanurans, including basal coelurosaurs, such as Zuolong (Choiniere et al., 2010) and tyrannosauroids (Currie, 2003; Xu et al., 2004).”

“Furthermore, various studies documented ontogenetic variation in both number and morphology of teeth within theropod dinosaurs (Colbert, 1989; Carr, 1999; Rauhut & Fechner, 2005; Samman et al., 2005; Kundrát et al., 2008; Bever & Norell, 2009; Buckley et al., 2010; Tsuihiji et al., 2011; Rauhut et…”

“28), as in all other specimens of Archaeopteryx where the ischium is preserved (Elzanowski, 2002; Foth, Tischlinger & Rauhut, 2014), as well as in Sinovenator (Xu et al., 2002), Jianianhualong (Xu et al., 2017), Microraptor (Hwang et al., 2002), and Xiaotingia (Xu et al., 2011).”

“As in all non-avialan maniraptoran theropods, with the possible exception of Scansoriopterygidae (Zhang et al., 2008; Czerkas & Feduccia, 2014), the pubis is considerably longer than the ischium (Fig.”

“, 2017), and Aurornis (Godefroit et al., 2013b), in which the postorbital is a rather plate-like element with a notably short ventral process, this bone is slender in Archaeopteryx, with the ventral process being the longest of the three processes.”

“A similar gap is also present e.g. in Anchiornis (BMNHC PH822; Pei et al., 2017), Mei (Xu & Norell, 2004), Jianianhualong (Xu et al., 2017), Sapeornis (Zhou & Zhang, 2003b; Provini, Zhou & Zhang, 2009) and in various non- Rauhut et al. (2018), PeerJ, DOI 10.7717/peerj.4191 69/101 pennaraptoran theropods (Currie & Chen…”

“Because the Eichstätt specimen is a juvenile individual (Wellnhofer, 1974; Erickson et al., 2009), we excluded this specimen in a second analysis, to”

“However, a similar number of teeth is found in Dromaeosaurus (nine maxillary teeth; Currie, 1995), and most other dromaeosaurids have only a few teeth more (see Xu & Wu, 2001; Currie & Varricchio, 2004; Pei et al., 2014).”

“…is clearly strongly pneumatized, with the preserved structures of the broken anterior end indicating a camellate structure, as present in Aerosteon, carcharodontosaurids, ornithomimosaurs, tyrannosaurids, oviraptorosaurs, and modern birds (Britt, 1993; Sereno et al., 2008; Evers et al., 2015).”

“If so, the variation in the dentition of Archaeopteryx might represent to some degree a Jurassic equivalent to the famous Darwin Finches, in which species show a great variety in the shape of their beaks, correlating with respective diet spectra (Sato et al., 2001; Abzhanov et al., 2006; Lamichhaney et al., 2015).”

“tetanuran theropods (Sereno et al., 1994; Rauhut, 2003), the medial condyle is placed entirely distal to the tibia, as in basal theropods (Rauhut & Carrano, 2016).”

“A similar gap is also present e.g. in Anchiornis (BMNHC PH822; Pei et al., 2017), Mei (Xu & Norell, 2004), Jianianhualong (Xu et al., 2017), Sapeornis (Zhou & Zhang, 2003b; Provini, Zhou & Zhang, 2009) and in various non- Rauhut et al. (2018), PeerJ, DOI 10.7717/peerj.4191 69/101 pennaraptoran theropods (Currie & Chen…”

“, 2012), tyrannosauroids (Lambe, 1917; Xu et al., 2012), Scipionyx (Dal Sasso & Maganuco, 2011), compsognathids (Fig.”

“However, such a depressed rim is absent in the dromaeosaurids Dromaeosaurus (Currie, 1995), Velociraptor (Norell, Makovicky & Clark, 2004), and Tsaagan (Norell et al., 2006), the troodontids Sinovenator (Xu et al.”

“In contrast to dromaeosaurids (Rauhut, 2003), the foramen is closed ventrally and anteroposteriorly elongate, as in the troodontid Zanabazar (Norell et al., 2009).”

“In other pennaraptorans, including oviraptorosaurs (Clark, Norell & Rowe, 2002; Balanoff & Norell, 2012), most dromaeosaurids (Barsbold & Osmólska, 1999; Norell et al., 2006; Novas et al., 2009; Pei et al., 2014), troodontids (Currie, 1985; Xu & Norell, 2004; Norell et al.”

“Thus, the presence of four premaxillary teeth, a premaxilla that projects anteriorly beyond the mandible, a furcula without hypocleideum, and the presence of 23 presacral and five sacral vertebrae all represent the normal character states for non-avialan theropods (see e.g. Raath, 1977; Currie & Zhao, 1993a; Brochu, 2…”

“The rounded anterior border of the external narial opening is placed above or just behind the fourth premaxillary tooth, as in other specimens (Wellnhofer, 1974;Mayr et al., 2007).”

“Furthermore, various studies documented ontogenetic variation in both number and morphology of teeth within theropod dinosaurs (Colbert, 1989; Carr, 1999; Rauhut & Fechner, 2005; Samman et al., 2005; Kundrát et al., 2008; Bever & Norell, 2009; Buckley et al., 2010; Tsuihiji et al., 2011; Rauhut et al., 2012), which s…”

“…vertebrae at the base of the neck, sometimes called pectorals (see e.g. Welles, 1984), and several authors have assumed the number of cervical vertebrae and dorsal vertebrae to be nine and 14, respectively (Lambe, 1917; Gilmore, 1920; Madsen, 1976; Zhao & Currie, 1993; Zhao et al., 2010).”

“When compared, Eosinopteryx possesses 20 caudals (Godefroit et al., 2013a), Anchiornis has approximately 31–32 vertebrae (Pei et al., 2017), while the caudal series of Jeholornis varies between 22 and 27 vertebrae (Zhou & Zhang, 2002, 2003a; O’Connor et al., 2012).”

“…vertebrae at the base of the neck, sometimes called pectorals (see e.g. Welles, 1984), and several authors have assumed the number of cervical vertebrae and dorsal vertebrae to be nine and 14, respectively (Lambe, 1917; Gilmore, 1920; Madsen, 1976; Zhao & Currie, 1993; Zhao et al., 2010).”

“These changes probably correlate with ontogenetic shifts in the diet spectrum (Farlow, 1976; Rauhut et al., 2012) as documented in extant crocodylians (Cott, 1961; Hutton, 1987; Webb, Hollis & Manolis, 1991; Da Silveira & Magnusson, 1999; Horna, Cintra & Ruesta, 2001).”

“Looking at early juvenile specimens of Enantiornithes from the Jehol Group, no plate-like sternum, but several small, isolated, ossified sternal loci are preserved, which were not connected to each other by bone tissue (Chiappe, Ji & Ji, 2007; Zheng et al., 2012; O’Connor et al., 2015b).”

“…in the absence of more rigorous approaches to the taxonomy of Archaeopteryx (e.g. by summarising all morphological and morphometric variation in a phylogenetic analysis on specimen level; see e.g. Yates, 2003; Tschopp, Mateus & Benson, 2015), this hypothesis must remain speculative at the moment.”

“…the condyles of the astragalus face anterodistally, as it is usual in Rauhut et al. (2018), PeerJ, DOI 10.7717/peerj.4191 48/101 tetanuran theropods (Sereno et al., 1994; Rauhut, 2003), the medial condyle is placed entirely distal to the tibia, as in basal theropods (Rauhut & Carrano, 2016).”

“This probably represents the natural association between these structures, as the gastralia are connected with the sternum and the pubis by midventral ligaments and are embedded in the M. rectus abdominis in recent reptiles (Carrier & Farmer, 2000; Claessens, 2004; Fechner & Schwarz-Wings, 2013).”

“Current information on dental variability mainly concerns variability in the number of teeth between different individuals (Madsen, 1976; Raath, 1977; Colbert, 1989, 1990) or the variabilty of tooth shape within a single dentition (Smith, 2005, 2007; Hendrickx, Mateus & Araújo, 2015b).”

“, 2012), Scipionyx (Dal Sasso & Maganuco, 2011), compsognathids (Fig. 38E; e.g. Currie & Chen, 2001;Hwang et al., 2004; Peyer, 2006; Ji et al., 2007; Hu, Wang & Huang, 2016), ornithomimosaurs (Osborn, 1916; de Klerk et al.”

“As in other Archaeopteryx specimens, no traces of an ossified sternum are preserved in the new specimen, which is similar to the condition in Anchiornis,Mei, Sapeornis (Zheng et al., 2014), Jianianhualong (Xu et al.”

“Current information on dental variability mainly concerns variability in the number of teeth between different individuals (Madsen, 1976; Raath, 1977; Colbert, 1989, 1990) or the variabilty of tooth shape within a single dentition (Smith, 2005, 2007; Hendrickx, Mateus & Araújo, 2015b).”

“, 2017), Sapeornis (Zhou & Zhang, 2003b) and various dromaeosaurids (Hone et al., 2010; Xu et al., 2010; Han et al., 2014; Lü & Brusatte, 2015).”

“, 2015a), Gobivenator (Tsuihiji et al., 2014), and Confuciusornis (Chiappe et al.”

“The anterior extension of the gastralia itself, however, is similar to Pennaraptora (except of Archaeopteryx, Anchiornis, Mei, Sapeornis), but in the latter the gap is absent due the development of ossified sternal plates (Xu et al., 2010; Pei et al., 2014; O’Connor et al., 2015a).”

“, 2014), Jianianhualong (Xu et al., 2017), and most non-pennaraptoran theropods (Weishampel, Dodson & Osmólska, 2004, see below).”

“Furthermore, different tooth counts might also be due to ontogenetic variation (see Rauhut & Fechner, 2005; Kundrát et al., 2008; Bever & Norell, 2009).”

“are usually correlated with large size in basal tetanurans (Madsen, 1976; Britt, 1991; Currie & Zhao, 1993a), but are also found in a few small-bodied coelurosaurs, such as Compsognathus (Ostrom, 1978; Peyer, 2006) and alvarezsaurids (Chiappe, Norell & Clark, 2002; Xu et al.”

“Thus, the presence of four premaxillary teeth, a premaxilla that projects anteriorly beyond the mandible, a furcula without hypocleideum, and the presence of 23 presacral and five sacral vertebrae all represent the normal character states for non-avialan theropods (see e.g. Raath, 1977; Currie & Zhao, 1993a; Brochu, 2…”

“In contrast, there is only a very slight dorsal expansion towards the acromion process, which is more anteriorly than dorsally directed, as in other paravians (Forster et al., 1998; Norell & Makovicky, 1999; Xu, Wang & Wu, 1999; Xu et al., 2002, 2011; Gianechini & Apesteguia, 2011; Brusatte et al., 2013; Lefèvre et al…”

“, 2007; Hu, Wang & Huang, 2016), ornithomimosaurs (Osborn, 1916; de Klerk et al., 2000; Varricchio et al., 2008), oviraptorosaurs (Zhou et al.”

“, 2014), while they seem to be unfused in Sinornithosaurus (Xu & Wang, 2000), Deinonychus (Ostrom, 1969) and Anchiornis (Pei et al., 2017).”

“…teeth; rimmed posterior margin of trigeminal foramen; intermediate process of the ischium Archaeopteryx lithographica (neotype of type species) Owen (1863), de Beer (1954), Ostrom (1976), Walker (1985), Dominguez Alonso et al. (2004) 2 Berlin specimen Eight to nine maxillary teeth; shape of…”

“…1997; Clark, Norell & Chiappe, 1999; Hwang et al., 2002; Burnham, 2004; Godfrey & Currie, 2004; Xu et al., 2010; Pei et al., 2014), which were fused into a keeled sternum in Ornithothoraces (Chiappe et al., 1999; Zhou, 2002; Clarke, Zhou & Zhang, 2006; O’Connor et al., 2011; Hu et al., 2015).”

“…reconfiguration of pelvic and thoracal musculature (Carrier & Farmer, 2000), a post-mortem displacement of the gastral basket after death due to tension is unlikely, as muscle tones are triggered by nerve impulses, occurring only pre- and perimortem (Leisman & Koch, 2009; Reisdorf & Wuttke, 2012).”

“As in other specimens of Archaeopteryx (Britt et al., 1998; Christiansen & Bonde, 2000), it has a well-developed pneumatic foramen on the anteroventral side of the centrum (Fig.”

“A large, short-armed, winged dromaeosaurid (Dinosauria: Theropoda) from the Early Cretaceous of China and its implications for feather evolution.”

“In the latter two species the sternal elements are even fused and keeled, resembling the condition of Ornithothoraces.”

“6, 7 and 9), rather than the T-shaped element seen in basal tetanurans, including basal coelurosaurs, such as Zuolong (Choiniere et al., 2010) and tyrannosauroids (Currie, 2003; Xu et al., 2004).”

“In the latter two species the sternal elements are even fused and keeled, resembling the condition of Ornithothoraces.”

“, 2017), Sapeornis (Zhou & Zhang, 2003b) and various dromaeosaurids (Hone et al., 2010; Xu et al., 2010; Han et al., 2014; Lü & Brusatte, 2015).”

“…is clearly strongly pneumatized, with the preserved structures of the broken anterior end indicating a camellate structure, as present in Aerosteon, carcharodontosaurids, ornithomimosaurs, tyrannosaurids, oviraptorosaurs, and modern birds (Britt, 1993; Sereno et al., 2008; Evers et al., 2015).”

“4 mm) of the lateral ramus (5 mm), as in the Munich specimen, but unlike the situation in non avialan theropods, which usually have a rather short (as long as or shorter than the lateral wing) and often broad pterygoid wing (Ostrom, 1969; Madsen, 1976; Currie & Zhao, 1993a; Barsbold & Osmólska, 1999; Currie, 2003; Lau…”

“Thus, the basal therizinosauroid Jianchangosaurus (Pu et al., 2013), the basal alvarezsauroid Haplocheirus (J. N. Choiniere, 2016, personal communication to OR), the basal troodontid Liaoningvenator (Shen et al., 2017), and dromaeosaurids, including the basal form Microraptor (Pei et al., 2014) and more derived taxa (…”

“Of the 11 Archaeopteryx specimens recovered so far, the vast majority comes from the Altmühltal Formation (‘Solnhofen limestones’ sensu stricto; Niebuhr & Pürner, 2014).”

“, 2014), and avialans (Zhou, Clarke & Zhang, 2008; Zhang et al., 2013), the lacrimal has a pronounced posterior process, resulting in a T-shaped outline of this bone.”

“Furthermore, various studies documented ontogenetic variation in both number and morphology of teeth within theropod dinosaurs (Colbert, 1989; Carr, 1999; Rauhut & Fechner, 2005; Samman et al., 2005; Kundrát et al., 2008; Bever & Norell, 2009; Buckley et al., 2010; Tsuihiji et al., 2011; Rauhut et al., 2012), which se…”

“However, all non-maniraptoran theropods in which the vertebral column and the ribs or rib heads are preserved have 10 cervical vertebrae, including coelophysoids (Raath, 1977; Colbert, 1989; You et al., 2014), ceratosaurs (Bonaparte, Novas & Coria, 1990; O’Connor, 2007), megalosauroids (Sadleir, Barrett & Powell, 2008…”

“Current information on dental variability mainly concerns variability in the number of teeth between different individuals (Madsen, 1976; Raath, 1977; Colbert, 1989, 1990) or the variabilty of tooth shape within a single dentition (Smith, 2005, 2007; Hendrickx, Mateus & Araújo, 2015b).”

“…teeth within theropod dinosaurs (Colbert, 1989; Carr, 1999; Rauhut & Fechner, 2005; Samman et al., 2005; Kundrát et al., 2008; Bever & Norell, 2009; Buckley et al., 2010; Tsuihiji et al., 2011; Rauhut et al., 2012), which seems to be most extremely developed in the basal ceratosaur Limusaurus…”

“In more derived avialans, the pubic apron is further reduced; it extends over slightly less than half the length of the pubis in Jeholornis (O’Connor et al., 2012), about a third in Confuciusornis (Chiappe et al.”

“35C), lacks a mandibular fenestra, has the diagnostic tooth morphology in the anteriormost dentary teeth, nine cervical vertebrae, and an ‘intermediate process’ on the ischium (Wellnhofer, 1993; Elzanowski & Wellnhofer, 1996; Rauhut, 2014).”

“These changes probably correlate with ontogenetic shifts in the diet spectrum (Farlow, 1976; Rauhut et al., 2012) as documented in extant crocodylians (Cott, 1961; Hutton, 1987; Webb, Hollis & Manolis, 1991; Da Silveira & Magnusson, 1999; Horna, Cintra & Ruesta, 2001).”

“(2007) recently argued that metatarsal I is attached medially, not posteromedially to metatarsal II and lacks the torsion that constitutes most to opposability in modern birds (Middleton, 2001), indicating that the condition in Archaeopteryx was similar to other non-avialan theropods in that the first digit is paralle…”

“…elements were completely absent in these species, and that the m. pectoralis, responsible for the ventral movement of the forelimbs, was alternatively attached between the proximal end of the humerus and the anterior portion of the gastral basket (Zheng et al., 2014; O’Connor et al., 2015a).”

“When compared, Eosinopteryx possesses 20 caudals (Godefroit et al., 2013a), Anchiornis has approximately 31–32 vertebrae (Pei et al., 2017), while the caudal series of Jeholornis varies between 22 and 27 vertebrae (Zhou & Zhang, 2002, 2003a; O’Connor et al., 2012).”

“However, since the 1970s, an increasing number of new (or newly identified) specimens have been described (Ostrom, 1970, 1972; Mayr, 1973;Wellnhofer, 1974, 1988a, 1993;Mäuser, 1997;Mayr, Pohl & Peters, 2005;Wellnhofer & Röper, 2005; Tischlinger, 2009; Foth, Tischlinger & Rauhut, 2014), making…”

“A similarly large offset in the premaxilla is present in the Solnhofen (Wellnhofer, 1992) and, probably, the London specimens (Howgate, 1984b), whereas it is present, but notably smaller in the Berlin, Eichstätt, Thermopolis, and 11th specimens (Dames, 1884; Wellnhofer, 1974, 1988b, 1992, 2008,…”

“are usually correlated with large size in basal tetanurans (Madsen, 1976; Britt, 1991; Currie & Zhao, 1993a), but are also found in a few small-bodied coelurosaurs, such as Compsognathus (Ostrom, 1978; Peyer, 2006) and alvarezsaurids (Chiappe, Norell & Clark, 2002; Xu et al., 2013).”

“As in several other specimens of Archaeopteryx (Wellnhofer, 2008, 2009), the distal end of several of the anterior dorsal ribs is notably thickened (Figs.”

“A transverse groove across the condyles is absent; such a groove is present in many nonmaniraptoran theropods (Rauhut, 2003), and probably represents a remnant of the suture between separate ossifications of the astragalar body and the ascending process (Rauhut & Pol, 2017).”

“Likewise, Heller (1959) noted the Rauhut et al. (2018), PeerJ, DOI 10.7717/peerj.4191 49/101 possible fusion of the proximal ends of the metatarsals of the Maxberg specimens, but did not comment on the distal tarsals.”

“Current research has shown increasing evidence that the different basins of the Late Jurassic limestones of Bavaria are characterised by different ages and fossil assemblages (Röper, 2005; Schweigert, 2007, 2015; Viohl & Zapp, 2007; López-Arbarello & Schröder, 2014; Ebert, Kölbl-Ebert & Lane, 2015; Rauhut et al., 2017…”

“…1997; Clark, Norell & Chiappe, 1999; Hwang et al., 2002; Burnham, 2004; Godfrey & Currie, 2004; Xu et al., 2010; Pei et al., 2014), which were fused into a keeled sternum in Ornithothoraces (Chiappe et al., 1999; Zhou, 2002; Clarke, Zhou & Zhang, 2006; O’Connor et al., 2011; Hu et al., 2015).”

“However, since the 1970s, an increasing number of new (or newly identified) specimens have been described (Ostrom, 1970, 1972; Mayr, 1973;Wellnhofer, 1974, 1988a, 1993;Mäuser, 1997;Mayr, Pohl & Peters, 2005;Wellnhofer & Röper, 2005; Tischlinger, 2009; Foth, Tischlinger & Rauhut, 2014), making…”

“The monophyly of Archaeopteryx and referral of the new specimen to this taxon Up to recently, the referral of new specimens from the Solnhofen Archipelago to the genus Archaeopteryx, or at least to the Archaeopterygidae (see Elzanowski, 2002) seemed unproblematic, as the known specimens (even more fragmentary ones, su…”

“A similar gap is also present e.g. in Anchiornis (BMNHC PH822; Pei et al., 2017), Mei (Xu & Norell, 2004), Jianianhualong (Xu et al., 2017), Sapeornis (Zhou & Zhang, 2003b; Provini, Zhou & Zhang, 2009) and in various non- Rauhut et al. (2018), PeerJ, DOI 10.7717/peerj.4191 69/101 pennaraptoran theropods (Currie & Chen…”

“Given that Schweigert (2005) calculated an average duration of 165,000 years per ammonite horizon in the Late Jurassic, this thus represents approximately 700,000 to one million years (see also Viohl, 2015b).”

“A similarly large offset in the premaxilla is present in the Solnhofen (Wellnhofer, 1992) and, probably, the London specimens (Howgate, 1984b), whereas it is present, but notably smaller in the Berlin, Eichstätt, Thermopolis, and 11th specimens (Dames, 1884; Wellnhofer, 1974, 1988b, 1992, 2008,…”

“5.27), so the presence of this character can be demonstrated for the neotype specimen of Archaeopteryx lithographica, the type species of the genus Archaeopteryx (ICZN, 2011; see also Bühler & Bock, 2002; Bock & Bühler, 2007).”

“…95 genus-level operational taxonomic units (OTUs) phylogenetically bracketed between the basal sauropodomorphEoraptor lunensis (Sereno et al. 1993, 2013) and the basal avialan Archaeopteryx lithographica (Meyer 1861; Howgate 1984; Rauhut 2014; Rauhut et al. 2018; Supplementary material 1.2 and 2).”

“Members of both groups resemble basal avialans such as Jeholornis and Sapeornis in having an anteroposteriorly short and dorsoventrally tall skull with small orbits and a very deep premaxilla and dentary, and in possibly being herbivorous.”

“Since its first discovery in 1861, only twelve skeletons of Archaeopteryx (Wellnhofer 2009; Foth et al. 2014; Rauhut et al. 2018) have been officially announced to the public.”

“The pubic shafts are nearly straight and distally form a symphysis that extends approximately a quarter of the length of the pubis, and that length is proportionally shorter than the symphysis in other nonornithothoracine birds (6, 11, 13).”

“(B) Right pedal claw from the 12 Archaeopteryx specimen [21].”

“…Austria, Belgium, Czech Republic, Denmark, France, Germany, Italy, Lebanon, The Netherlands, Poland, Russia, Slovenia, Spain, Switzerland, UK; see Haug and Haug 2016b; Ouden and Pouwer 2018; Rauhut 2018; Furrer 2019; Fossiel.net Team 2020; ÖPG 2020; PalGes 2020), including the USA (MacFadden et al.”

“These taxa are phylogenetically bracketed between the early saurischian Herrerasaurus ischigualastensis (Sereno and Novas 1992, 1994) and the avialan Archaeopteryx lithographica (Meyer 1861; Howgate 1984; Rauhut 2014; Rauhut et al. 2018; Supplementary Data1).”

“By contrast, the pubic shaft is either straight or weakly bowed ventrally in other enantiornithines, as well as in other basal birds (Zhou & Zhang 2003; Ji et al. 2011; Wang & Zhou 2017b; Wang et al. 2017; Rauhut et al. 2018).”

“This dataset (referred to as the Hastings + Young matrix, or HY matrix) is continually being revised (e.g., Ristevski et al., 2018; Ősi et al., 2018, Foffa et al. 2019; Sachs et al. 2019; Young et al. 2020a, 2020b; Johnson et al. 2020), and herein we revise the most recent version in Young et al.…”

“The same seems to be true for the recently described 12th Archaeopteryx specimen (Rauhut et al., 2018).”

“In total, the genus Archaeopteryx seems to span some 700,000 to one million years, and notable variation between the different specimens might indicate evolutionary changes over this time (Rauhut et al., 2018).”

“, 2020) instead of the form Unenlagiinae that has been employed by several authors (Makovicky et al., 2005; Turner et al., 2007, Turner et al., 2012; Brusatte et al., 2015; Cau et al., 2017; Rauhut et al., 2018; Pei et al., 2020).”

“These soft tissues, together with the short reversed hallux 11 , are consistent with previous interpretations based on the proportions of the pedal phalanges in digit III, which place Archaeopteryx in the morphospace where terrestrial and arboreal birds overlap, and indicate Archaeop-teryx could…”

“This is a plesiomorphy shared with non- avian theropods and other stem birds including Archaeopteryx and Sapeornis (Hu et al., 2020a; Rauhut et al., 2018), contrasting with the reduced or absent postorbital bar in the Ornithothoraces including modern birds (Hu et al.”

“The postorbital in LP4450 retains the plesiomorphic triradiate morphology with a remarkably elongate jugal process, similar to but more slender than the condition in Archaeopteryx and differing from this basal-most taxon in that the jugal process does not reach the jugal, representing the break of a complete postorbit…”

“Additionally, camellate intraosseous pneumatic structures in the last two cervical vertebrae, as well as a pneumatic foramen in the 1st thoracic vertebra (Rauhut et al. 2018, p.30; Fig.”

“Other authors likewise applied the term to openings in the lateral body of the thoracic vertebrae (e.g., Sereno et al. 2007; Novas et al. 2008; Rauhut et al. 2018).”

“In the newly reported 12th specimen of Archaeopteryx, the foramen, termed the mylohyoid foramen (Rauhut et al., 2018), is more rostrally positioned between the rostral tip and the dorsal margin apex of the splenial.”

“In Sapeornis and most other non-ornithothoracine avialans, the acrocoracoid process is slightly higher than the coracoidal glenoid fossa, which would have caused the tendon of m. supracoracoideus to be slightly dorsally displaced relative to its position in Archaeopteryx and non-avialan pennaraptorans (Mayr et al., 20…”

“The three wing digits of this species have the phalangeal formula [x-2-3-4-x], see Rauhut et al. (2018).”

“Therefore, the specimen described herein is a contemporary of the oldest known Archaeopteryx from a neighbouring basin (Rauhut et al., 2018, figure 1).”

“While former has been considered a synapomorphy of the Dromaeosauridae by some authors (Turner et al. 2012), other paravians, such as troodontids (Zanno et al. 2011), Anchiornis (Hu et al. 2009), and Archaeopteryx (Rauhut et al. 2018), have the non-ginglymoid metatarsal II.”

“…in dinosaurs (e.g., the early sauropodomorph Eoraptor lunensis: Sereno et al., 2012; the early neotheropod Megapnosaurus rhodesiensis: Raath, 1977; the early ornithischian Heterodontosaurus tucki: Norman et al., 2011), including the early avialan Archaeopteryx lithographica (Rauhut et al., 2018).”

“A large free postorbital is present in Archaeopteryx, the basal pygostylians Sapeornis and Confuciusornis, and some Early Cretaceous enantiornithines, in which it articulates with the jugal to form a complete postorbital bar (Wang et al. 2010, 2019; Rauhut et al. 2018; Hu et al. 2020a, b).”

“The notch in the postorbital process is deeper than in Archaeopteryx (Elzanowski and Wellnhofer, 1996), but not as pronounced as in Deinonychus (Ostrom, 1969).”

“A new specimen of Archaeopteryx sp. has gastralia articulated with the midshaft of the pubis (Rauhut et al., 2018), but a HLPT is FIGURE 8.”

“Even in the most iconic bird species Archaeopteryx lithographica , several different age stages have been identified (Rauhut et al., 2018).”

“The femoral shaft is relatively robust and straight, in contrast to most Paraves, where the shaft is curved (Norell and Makovicky, 1999; Zhou and Zhang, 2006; Clarke et al., 2006; O’Connor et al., 2011; Rauhut et al., 2018).”

“Although not yet systematically reviewed, tooth enamel has been reported to regularly fl uoresce within this color spectrum under UV light, with con fi rmation of this speci fi c histological reactivity in sauropsids (Frey & Tischlinger, 2012; Rauhut et al., 2018; Hone et al., 2023; Sera fi ni et al., 2023, 2024); most of…”

“…et al. 2021), basal troodon-tids, such as Sinovenator (Xu et al. 2002), and the basal avialans Archaeopteryx , Jeholornis , Confuciusornis , and Jinguofortis (Wellnhofer 1974; Chiappe et al. 1999; Zhou and Zhang 2002, 2003; Mayr et al. 2007; Foth et al. 2014; Rauhut et al. 2018; Wang et al. 2018).”

“Several tissue types, including keratin, bone and chitin, fluoresce under UV light, and our abilities to detect ever more subtly fluorescing forms of these tissues have improved within recent years (Scaphognathus [Jäger et al. 2018]; Archaeopteryx [Rauhut et al. 2018]).”

“This was accompanied by increasing distal tarsal fusion in maniraptorans (Norell and Makovicky 1997, 1999; Rauhut et al. 2018), with complete fusion of the distal tarsals and metatarsals to form the tarsometatarsus in Avialae (Baumel and Witmer 1993; OssaFuentes et al.”

“The robust femur measures 70 % of the length of the tibia, comparable to that of Archaeopteryx and Anchiornis ( 19 , 22 ), but pro-portionately longer than in Fujianvenator (table S3) ( 10 ).”

“…localities in Asturias have been assigned to indeterminate theropods, probable ceratosaurians, indeterminate tetanu-rans, megalosaurids, possible carcharodontosau-rids, and indeterminate maniraptorans (e.g., Canudo and Ruiz-Omeñaca, 2001; Ruiz-Omeñaca et al., 2008; Rauhut et al., 2018b).”

“2011), burrows (Crimes and Droser 1992), skin impressions (Bell 2012), and feather impressions (Foth and Rauhut 2017; Rauhut et al. 2018).”

“…can be diagnosed by the following combination of characters: a jugal with a longitudinal groove on the medial side of the suborbital process (Rauhut et al. 2018); an infratemporal fenestra with a sharply angled incision at the anteroventral margin separating the quadra-tojugal and…”

“2017; Cau 2018) and archosaur species possessing unequivocal flight feathers are described as theropod dinosaurs (e.g., Hu et al. 2018; Rauhut et al. 2018).”