The tenth skeletal specimen of Archaeopteryx

“This feature is otherwise known only from the basal avian Rahonavis and deinonychosaurs (Dromaeosauridae and Troodontidae), and its presence in Archaeopteryx provides additional evidence for a close relationship between deinonychosaurs and avians.”

“, Velociraptor mongoliensis IGM 100/985, Archaeopteryx lithographica [Mayr et al., 2007], Mei long IVPP 12733).”

“specialized second pedal digit as in deinonychosaurs (61); Jeholornis (Fig.”

“Although few unambiguously pneumatic vertebrae are well preserved in Archaeopteryx, cervical vertebrae are unambiguously pneumatic, and middle-posterior dorsal and caudal vertebrae are definitely apneumatic.”

“Some workers have doubted that a postorbital bone was present (Bühler, 1985; Martin and Zhou, 1997), but most workers accept that it was indeed present (Chatterjee, 1991; Elza- nowski and Wellnhofer, 1996; Chiappe et al., 1999; Elzanowski, 2001, 2002; Witmer, 2002; Paul, 2002; Mayr et al., 2007).”

“Although there has been some debate, the hallux of Archaeopteryx is now thought to have been medially directed rather than fully reversed ([80]; see Supporting Information Text S1).”

“In contradiction to some previous studies, hallucal orientation in non-avian theropods is uniformly unreversed, a condition preserved relatively unaltered in basal birds (e.g. Rahonavis, Archaeopteryx; Mayr et al. 2005, 2007) until some point within Ornithothoraces.”

“Paleontological Specimen Details This Archaeopteryx is preserved within a matrix of limestone from the Solnhofen region of Bavaria, Germany (3, 4) and was selected because of its remarkable preservation.”

“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).”

“Visible from the interior surface of the parietals, a ventral depression may represent the pineal fossa; this feature is not obvious externally, similar to Archaeopteryx (Alonso et al., 2004).”

“The epicleideal processes are unexpanded and continuous with the rami as with Bambiraptor feinbergi (AMNH FR 30554) and Archaeopteryx lithographica (Mayr et al., 2007).”

“This number is similar to dromaeosaurids, Archaeopteryx, and Jinfengopteryx, but is less than in other troodontids (Makovicky and Norell, 2004; Norell and Makovicky, 2004; Ji et al., 2005; Mayr et al., 2005, 2007).”

“, 1999), but not in other taxa including Archaeopteryx (Mayr et al., 2007) and also not in Anchiornis (Pei et al.”

“However, such a sac is not likely homologous with that of ornithothoracine birds because its osteological indicator (furcular pneumatisation) is absent in phylogenetically intermediate taxa, including other allosauroids (Chure and Madsen 1996), basal birds (Chiappe et al. 1999; Zhou and Zhang 2003; Mayr et al. 2007) a…”

“Its pubes have become disarticulated from the ilia and rotated into a retroverted position in most specimens [49,92,93]; the pubes are vertical in the one specimen of Archaeopteryx in which they retain articulation with the ilia [94].”

“including unenlagiids, Anchiornis, Xiaotingia, and basal avialans such as Archaeopteryx, Jeholornis, and Sapeornis, the sternum is small (as is the case in Jeholornis) or not ossified, and the uncinate processes are totally absent (probably not ossified; Zhou and Zhang, 2002, 2003b; Mayr et al., 2007).”

“All non-avian theropods, and the first bird Archaeopteryx, lack a reversed hallux [20].”

“Only the Thermopolis specimen seems to show a slightly flexed pubic shaft [24], but the bone is seen in anterolateral view, making a final validation impossible.”

“In contrast, archaeopterygids (e.g. Mayr et al., 2007; Wellnhofer, 2008) and non-avian theropods (e.g. Hwang et al., 2002) exhibit single, well-developed, craniomedially positioned cnemial crests on the proximal ends of their tibiae.”

“Similar to enantiornithines, the scapula is straight, slender, tapers distally, and differs from the stout, blunt-ended morphology seen in Archaeopteryx and confuciusornithiforms (11, 13).”

“MK] (Mayr et al. 2007).”

“All Cretaceous birds for which the pedal skeleton is known are either anisodactyl (digit I reversed with respect to II–IV), the plesiomorphic state for all avians more derived than Archaeopteryx ( Mayr et al. 2005, 2007 ),”

“In most other basal birds including enantiornithines, the sacral centra are either subequal in dorsoventral depth and transverse width or wider transversely than deep dorsoventrally ( Zhang et al, 2001 ; Zhou and Zhang, 2003 ; Mayr et al, 2007 ).”

“In this regard, unenlagiids resemble troodontids and basal birds (e.g., Archaeopteryx, Jeholornis; Zhou and Zhang 2003b, Mayr et al. 2007), in which the lacrimal is “L”-shaped.”

“& Gerald Mayr Gerald.Mayr@senckenberg.de 1 Ornithological Section, Senckenberg Research Institute and Natural History Museum Frankfurt, Senckenberganlage 25, 60325 Frankfurt am Main, Germany”

“Archaeopteryx ‘Basal Aves’ Late Jurassic BMNH 37001 [78] 88”

“The jugal is preserved in five specimens of Archaeopteryx—the Berlin, Eichst€att, Munich, Thermopolis and the 11th specimen (Elzanowski and Wellnhofer, 1996; Elzanowski, 2002; Mayr et al., 2007; Foth et al., 2014).”

“Currie and Peng (1993) also noted the presence of a large lateral tuber on the hind limb of a juvenile troodontid, and all specimens of Archeopteryx exhibit a prominent tuber regardless of size (Wellnhofer, 1974; Mayr et al., 2007).”

“chaoyangensis, although the number of cervical vertebrae and dorsal vertebrae is relatively constant (Berger, 1956; Webster & Goff, 1977; Zhou & Zhang, 2003b; Mayr et al., 2007; Pu et al., 2013).”

“teriorly, similar to the condition in Dromaeosaurus and Archaeopteryx (Witmer, 1997; Mayr et al., 2007), but different from that of Saurornithoides and Gobivenator (Norell et al.”

“Although a jugal process is not preserved, a nonavian dinosaur like tetraradiate palatine cannot be ruled out since comparison with Archaeopteryx indicates that the delicate jugal process is easily broken off and lost during preservation (24, 25).”

“…these fossil taxa very close to the phylogenetic divergence of Aves (Turner et al. 2007), within nonavian theropods, whereas Archaeopteryx likely had morphology associated with the earliest flapping bird, at least in terms of its 9 9 6 EVOLUTION APRIL 2009 wingspan and body size (Mayr et al. 2007).”

“excellent descriptions of Wellnhofer (1974, 2008), Elzanowski and Wellnhofer (1996), and Elzanowski (2002), and to the numerous other contributions that have helped clarify the cranial structure of this taxon (e.g., Dames 1884; Heilmann 1926; Whetstone 1983; Walker 1985; Dominguez Alonso et al. 2004; Tischlinger 2005;…”

“…ratio is around 3:1 in Buitreraptor, but is less than 2:1 in most other basal paravians, including Velociraptor, Tsagaan (Norell et al., 2006), Sinornithosaurus, Mei (Xu and Wu, 2001), Anchiornis (Hu et al., 2009), Archaeopteryx (Mayr et al., 2007), and Confuciusornis (Chiappe et al., 1999).”

“In contrast to many other fossil taxa, it is these names, often in combination with the numbering outlined above, rather than specimen numbers that are usually used to identify the different specimens of Archaeopteryx and possible other basal avialans from the Kimmeridgian/Tithonian of Bavaria, even in the technical s…”

“…(1976); (d) based on Russell and Dong (1993); (f) modified from Gatesy and Middleton (1997); (h) based on Karhu and Rautian (1996); (i) based on Mayr et al. (2007) 28% 41% 31% 35% 39% 26% 42% 37% 21% 31% 44% 25% 38% 43% 19% 34% 47% 19% 34% 43% 23% 44% 38% 18% 31% 45% 24% 24% 41% 35% 17% 44% 39% 29% 41% 30% 29% 46% 25…”

“…suggests a jugal diverticulum was present in the earliest theropods Eoraptor and Herrerasaurus, in most non-avian theropods, and also in early birds such as Archaeopteryx (Sereno and Novas, 1993:fig.2B; Sereno et al., 1993:fig.2a, b; Mayr et al., 2005:fig.2D; Mayr et al., 2007:fig.5A).”

“Differences in the number of primary feathers in specimens of Archaeopteryx , 11 [e.g., the 10th specimen—WDC - CSG - 100 (47)] versus 12 [e.g., the 11th specimen (48)], may suggest these specimens do not represent a single taxon (49–51).”

“The antorbital fossa occupies a large portion of the lateral surface of the maxilla cranial to the internal antorbital fenestra, as in other troodontids [2,4,8,9], dromaeosaurids [23–26], and the basal bird Archaeopteryx [27].”

“The number of secondary feathers is known for a number of paravians and is quite variable, including 12-15 in Archaeopteryx (Stephan, 1987; Mayr et al., 2007; Foth et al., 2014), 10 in Anchiornis (Hu et al., 2009), 18 in Microraptor (Xu et al., 2003), and 14 in Velociraptor mongoliensis (Turner et…”

“Nonetheless, the following groups have been described with certainty: palaeognathous Lithornithidae (Houde 1988; Mayr 2007), anseriform Gastornithidae (Buffetaut 1997; Mayr 2007) and Presbyornithidae (Olson 1994; Benson 1999), Cariamae (Mayr 2007), Phorusrhacidae (Alvarenga and Ho¨fling 2003),…”

“Bird material from this locality is difficult to properly discern, as no complete skeletal material has been documented and teeth vary widely in morphology (Sankey et al., 2002; Mayr et al., 2007; Larson & Currie, 2013; Wilson, Chin & Cumbaa, 2016).”

“Instead, we consider here that the “last dorsal” identified by Mayr et al. (2007) actually conforms the first sacral, whereas the “first sacral” of Mayr et al. (2007) is here reidentified as the second one (Figure 7).”

“In Neuquenraptor the distal articulation of metatarsal I is ball-shaped and non-ginglymous as it occurs in Buitreraptor (MPCN-PV-598), troodontids (Xu and Wang 2000), and basal avialans, such as Archaeopteryx (Mayr et al. 2007).”

“and dromaeosaurids (Paul 1988; Forster et al. 1998; Mayr et al. 2007).”

“If this morphology is correctly interpreted here, it would resembles the condition in Archaeopteryx (Mayr et al., 2007) and some dromaeosaurids, such as Deinonychus (see Fig.”

“Although previously considered to be the fossil representative of an early modern bird, features such as a bony tail and teeth rule out A . lithographica from being considered a true avian ancestor [13].”

“…that the fourth lateral process (the ‘jugal’ process 19 ) is rostral to the choanal process (previously depicted as caudal to the choanal process 13 ) and formed a narrow contact with the maxilla near its caudal end, rather than with the jugal, as previously reconstructed 13 (Extended Data Fig.”

“If the above hypothesis is sustained, it will shed light on the long-debated hallucal orientation of Archaeopteryx (i.e., whether or not the hallux is fully reversed; Middleton, 2001; Mayr et al., 2005, 2007; Feduccia et al., 2007; Mayr and Peters, 2007; Dececchi and Larsson, 2011).”

“Even though they are absent in Archaeopteryx (Mayr et al. 2007; Wellnhofer 2009) and restricted to the caudalmost thoracic vertebrae in the Sapeornithiformes (Zhou and Zhang 2003), pronounced pleurocoels occur in the Confuciusornithiformes (Chiappe et al.”

“— Jeholornis compared to Archaeopteryx, with a new understanding of the earliest avian evolution.”

“96G), and approximately 90 % in Archaeopteryx (MAYR et al. 2007: fig.”

“The studies by Mayr et al. (2005, 2007) strengthen this relationship, although the diagnostic, stiff ened “ramphorhynchoid” tail of dromaeosaurs is absent in Archaeopteryx, which is primitive in this character.”

“, 2020), the bone is triradiate and lacks a jugal process present in Archaeopteryx and non- avialan dinosaurs (Figure 3—figure supplement 2a–f; Ostrom, 1969; Barsbold and Osmólska, 1999; Mayr et al., 2007; Kundrát et al., 2019).”

“Evidence for PSP in Archaeopteryx is equivocal (O’Connor 2006, Mayr et al. 2007, contra Britt et al. 1998, Christiansen and Bonde 2000).”

“…Avialae present in close outgroups, more distantly related theropods, Archaeopteryx, basal birds, and ornithurans (Alonso et al., 2004; Bell & Chiappe, 2020; Chiappe et al., 1999; Elzanowski et al., 2000; Elzanowski & Wellnhofer, 1996; Hendrickx et al., 2015; Mayr et al., 2007; Xu et al., 2015).”

“Therefore called the ‘Thermopolis specimen’, it was studied in detail by Mayr et al. (2005, 2007) and designated as Archaeopteryx siemensii.”

“The anatomy of the Archaeopteryx manus and wrist, where the primary feathers attach, is certainly very different to that seen in extant birds [22,23,24,25].”