Romain Vullo
email: romain.vullo@univ-rennes1.fr

Salvador Bailon
email: salvador.bailon@mnhn.fr

Yannicke Dauphin

Hervé Monchot
email: herve.monchot@wanadoo.fr

Ronan Allain
email: ronan.allain@mnhn.fr

A reappraisal of Jeddaherdan aleadonta (Squamata: Acrodonta), the purported oldest iguanian lizard from Africa

Keywords: Lepidosauria, Uromastyx, Morocco, Cretaceous, Quaternary, Raman spectroscopy

Jeddaherdan aleadonta

is currently known as the first and single Mesozoic iguanian lizard from Africa. The original description and age of the holotype and only known specimen (i.e. a dentary fragment bearing five teeth) are revised here. We show that this fragmentary specimen was misinterpreted anatomically, does not come from Cretaceous beds but is instead Quaternary in age, and must be assigned to an indeterminate species of Uromastyx (spiny-tailed lizards). Therefore, the genus Jeddaherdan is considered a junior synonym of Uromastyx, and the species J. aleadonta (= Uromastyx sp.) is considered a nomen dubium. Our results refute the presence of iguanian lizards in the Mesozoic of Africa and have major implications for reconstructing the evolution and palaeobiogeography of this group.

Introduction

 [START_REF] Apesteguía | The first iguanian lizard from the Mesozoic of Africa[END_REF]described Jeddaherdan aleadonta as a mid-Cretaceous acrodontan representing the oldest iguanian lizard from Africa and a biogeographic link between Cretaceous forms from Asia and South America. This species, based on a single fragmentary dentary bone (MNHN.F.MRS51.1) from southeastern Morocco, was recovered in [START_REF] Apesteguía | The first iguanian lizard from the Mesozoic of Africa[END_REF] phylogenetic analysis as an uromastycine agamid sister to Gueragama sulamericana from the Cretaceous of Brazil. Based on a detailed redescription and Raman spectroscopic analyses, our study challenges this interpretation and aims to test the hypothesis that MNHN.F.MRS51.1 is a recent (or subfossil) specimen belonging to the genus Uromastyx, a group of uromastycine lizards currently widespread throughout the Saharo-Arabian region (Wilms et al., 2009;[START_REF] Tamar | Evolutionary history of spiny-tailed lizards (Agamidae: Uromastyx) from the Saharo-Arabian region[END_REF].

Material and methods

MNHN.F.MRS51.1 was surface collected by René Lavocat at Gara Tabroumit (southeastern Morocco) together with vertebrate fossils derived from the Cretaceous Kem Kem beds (Lavocat, 1954a, b;[START_REF] Apesteguía | The first iguanian lizard from the Mesozoic of Africa[END_REF]. The material used for anatomical comparison consists of a series of isolated dentaries (including SHC YAM K17-SD4 S 414.1) of the Arabian spiny-tailed lizard (Uromastyx aegyptia) coming from the archaeological site of Al-Yamâma in Saudi Arabia [START_REF] Monchot | Archaeozoological evidence for traditional consumption of spiny-tailed lizard (Uromastyx aegyptia) in Saudi Arabia[END_REF]. In addition, a lower jaw of a recent Uromastyx acanthinura sensu lato (MNHN-ZA-AC-1928-242) was also examined (Table 1). MNHN.F.MRS51.1 is a holotype and thus cannot be used for destructive analyses, such as DNA analysis and radiometric dating. We used Raman spectroscopy (a nondestructive and non-invasive technique that requires no sampling or alteration of the specimen) to investigate and evaluate the taphonomic and diagenetic signature of six specimens from Gara Tabroumit (i.e. MNHN.F.MRS51.2, a fish vertebra; MNHN.F.MRS51.3 to MNHN.F.MRS51.6, four archosaur teeth; MNHN.F.MRS51.1, the holotype of Jeddaherdan aleadonta). For comparison, two modern lizard specimens (i.e. the abovementioned specimen SHC YAM K17-SD4 S 414.1, and the humerus of the above-mentioned specimen MNHN-ZA-AC-1928-242) were also analyzed by Raman spectroscopy (for details see electronic supplementary material) (Table 1).

Non-biogenic geological samples, i.e. hydroxylapatite and fluorapatite, were selected as references for Raman analyses. Hydroxylapatite comes from Holly Spring (Georgia, USA), and is available in the RRUF database (reference R06180). Fluorapatite (reference RRUF R050340) was collected at Buckingham (Quebec, Canada). In addition to the humerus of MNHN-ZA-AC-1928-242, modern biogenic apatites (bone, enamel, and dentine) used as references were a small dried fragment of a long bone of Sus scrofa (Mammalia: Suidae) and a tooth fragment of Hippopotamus amphibius (Mammalia: Hippopotamidae). A small rodent (Mammalia: Rodentia indet.) bone from the Pleistocene of Olduvai (Tanzania) was used as reference for fossil bones rich in rare earth elements (REE) (for details see electronic supplementary material).

Abbreviations: MNHN, Muséum national d'Histoire naturelle, Paris; SHC, Saudi Heritage Commission, al-Shimaysi store, Riyadh.

Results

Anatomy

Revised description of MNHN.F.MRS51.1 (Fig. 1): fragmentary right dentary restricted to the posteriormost portion of the dental row (five teeth preserved) and anterior portion of the coronoid process. The anterior, posterior and ventral portions of the bone are missing. The estimated original length of the dentary is about 25 mm. The specimen is broken ventral to the tooth row, thus exposing the Meckelian groove in lateral view. No mental foramina are preserved due to the fragmentary nature of the specimen. Medially, the subdental lamina (sensu [START_REF] Takesh | A monograph on the osteology of Mesopotamian spiny-tailed lizards, Saara loricata (Blanford, 1874) (Sauria: Agamidae: Uromastycinae)[END_REF] is partially preserved ventrally to the dental groove (sensu Čerňanský, 2010). The medial face of the specimen is heavily abraded, as indicated by the exposed pulp cavity of the last tooth. The ledge ventral to the tooth bases (sensu [START_REF] Rage | Valbro: A new site of vertebrates from the early Oligocene (MP 22) of France (Quercy). III -Amphibians and squamates[END_REF] and the dental groove are worn and poorly distinct. The incomplete coronoid process rises obliquely above the level of the tooth row. The anterior ridge of the coronoid originates posterior to the distolingual portion of the last tooth. Laterally, the coronoid process is convex due to the presence of the posterodorsally ascending crest (sensu [START_REF] Simões | A stem acrodontan lizard in the Cretaceous of Brazil revises early lizard evolution in Gondwana[END_REF]; medially, the coronoid process is flat due to the presence of the coronoid facet. The acrodont dentition consists of oblique, mesiolingually oriented teeth; the teeth become gradually more oblique from anterior to posterior positions. The tooth crowns are higher and more abrupt labially than lingually. The lingual faces bear a bulbous cingulum, partially covered by tooth ankylosis. In occlusal view, the anterior and posterior carinae originating from a blunt apex form a distolingually concave crest.

Taphonomy and Raman spectroscopic analyses

As MNHN.F.MRS51.1 was surface collected and is completely free of matrix, there is no direct evidence that this specimen originates from the mid-Cretaceous Kem Kem beds. The polished aspect and breaks displayed by MNHN.F.MRS51.1 may be due to predation (e.g. bites, digestive process) and/or weathering, as observed in many squamate remains from archaeological sites [START_REF] Stoetzel | Taphonomic analysis of amphibian and squamate remains from El Harhoura 2 (Rabat-Témara, Morocco): Contributions to palaeoecological and archaeological interpretations[END_REF][START_REF] Smith | To catch a chameleon, or actualism vs. natural history in the taphonomy of the microvertebrate fraction at Qesem Cave, Israel[END_REF][START_REF] Smith | A model of digestive tooth corrosion in lizards: experimental tests and taphonomic implications[END_REF][START_REF] Lev | Squamate bone taphonomy: A new experimental framework and its application to the Natufian zooarchaeological record[END_REF]. All the confirmed Cretaceous specimens (e.g. ganoid fish scales, theropod and pterosaur teeth) collected at the Gara Tabroumit site by Lavocat are brown to dark reddish brown, unlike MNHN.F.MRS51.1 which can be easily distinguished by its whitish pink color (see Fig. 2).

Raman spectra of fossil (Cretaceous) specimens from Gara Tabroumit are similar between each other (Fig. 2A), but clearly differ from those of the holotype of Jeddaherdan aleadonta and modern Uromastyx bones (Fig. 2B,C). The main band of apatite (1 PO4) at about 960 cm -1 is not detected in Cretaceous specimens. In the latter, the main bands are between 1100 and 1700 cm -1 , and they have no counterparts in modern specimens. Spectra of U. acanthinura s.l. (Recent) and U. aegyptia (Holocene) show the preservation of organic components (amide bands) (Fig. 2C). U. aegyptia and J. aleadonta have strong bands assigned to 4 PO4, whereas that of U. acanthinura s.l. is weaker (Fig. 2B,C). This suggests that the bones of J. aleadonta and the archaeological U. aegyptia were somewhat recrystallized, whereas the modern humerus of U. acanthinura s.l. was not modified. The values of the Full Width at Half Maximum (FWHM) confirm the low crystallinity of U. acanthinura s.l. (Fig. S3). Moreover, coefficient correlations between J. aleodonta and U. aegyptia on one hand, and J. aleodonta and a U. acanthinura s.l. on the other hand, are the highest (Table S1). [START_REF] Apesteguía | The first iguanian lizard from the Mesozoic of Africa[END_REF] described MNHN.F.MRS51.1 as an "incomplete left dentary missing the symphysial and posteriormost portions" and estimated the skull length as 22.3 mm [START_REF] Apesteguía | The first iguanian lizard from the Mesozoic of Africa[END_REF] fig. 1). Consequently, they noted that Jeddaherdan aleadonta was characterized by a low number of relatively large teeth compared with modern uromastycines, and that its teeth were mesiolabially oriented (instead of mesiolingually oriented in Uromastyx; [START_REF] Cooper | The dentition and dental tissues of the agamid lizard, Uromastyx[END_REF][START_REF] Holmes | Agamid lizard (Agamidae: Uromastycinae) from the lower Oligocene of Egypt[END_REF]. However, our redescription shows that the size, proportions and orientation of the specimen were misinterpreted by [START_REF] Apesteguía | The first iguanian lizard from the Mesozoic of Africa[END_REF] (Fig. 1F-H); therefore, some anatomical structures shown in their fig. 3 were also misidentified (Table 2). It clearly appears that MNHN.F.MRS51.1 actually represents a small portion of a larger right dentary (Fig. 1B). The combination of features on which [START_REF] Apesteguía | The first iguanian lizard from the Mesozoic of Africa[END_REF] based the diagnosis of J. aleadonta becomes inaccurate. Jeddaherdan is indistinguishable from Uromastyx, and the former is here synonymized with the latter (i.e. Jeddaherdan being a junior synonym of Uromastyx). Due to the incompleteness and poor preservation of the specimen, the species J. aleadonta should be considered a nomen dubium and we therefore refer MNHN.F.MRS51.1 to Uromastyx sp. It should be noted that as U. nigriventris (formerly U. acanthinura nigriventris) is the only species present in the Kem Kem region today (Wilms et al., 2009;[START_REF] Tamar | Evolutionary history of spiny-tailed lizards (Agamidae: Uromastyx) from the Saharo-Arabian region[END_REF], MNHN.F.MRS51.1 might belong to this species; however, as we cannot be sure about the past (Quaternary) distribution of other North African species of the genus, it is preferable to treat this specimen as an indeterminate species of Uromastyx.

Discussion

Data obtained from Raman spectroscopy strongly suggest two distinct taphonomic and diagenetic histories between MNHN.F.MRS51.1 and other specimens from Gara Tabroumit originating unambiguously from the mid-Cretaceous Kem Kem beds (MNHN.F.MRS51.2 to MNHN.F.MRS51.6). Unlike MNHN.F.MRS51.1, these mid-Cretaceous fossils may be rich in rare earth elements as suggested by their Raman spectra similar to that of the REE-rich fossil bone from Olduvai (see electronic supplementary material; Fig. S4). Interestingly, REE enrichment was also reported in vertebrate fossils from other mid-Cretaceous Kem Kem localities [START_REF] Hassler | Calcium isotopes offer clues on resource partitioning among Cretaceous predatory dinosaurs[END_REF]. The fact that MNHN.F.MRS51.1 shows no REE enrichment would indicate that this specimen does not originate from the mid-Cretaceous Kem Kem beds (Trueman, 1999). On the other hand, MNHN.F.MRS51.1 shows a similar spectrum to those of the bones of modern lizards (Uromastyx spp.). Therefore, it is considered here as late Quaternary in age, which is consistent with our conclusions based on anatomical evidence.

Jeddaherdan aleadonta, widely accepted as a mid-Cretaceous acrodontan since its original description (e.g. Ibrahim et al., 2020;[START_REF] Evans | The origin and early diversification of squamates[END_REF][START_REF] Ijouiher | The Desert Bones: The Paleontology and Paleoecology of Mid-Cretaceous North Africa[END_REF], has been considered in various studies as a key taxon critical for understanding the origin and evolutionary history of iguanian lizards, with important implications for both palaeobiogeographic reconstructions (Simoes et al., 2017;[START_REF] Bittencourt | Discovery of the oldest South American fossil lizard illustrates the cosmopolitanism of early South American squamates[END_REF][START_REF] Rage | Island Africa and vertebrate evolution: A review of data and working hypotheses[END_REF] and node calibrations [START_REF] Lafuma | Multiple evolutionary origins and losses of tooth complexity in squamates[END_REF][START_REF] Marjanović | The making of calibration sausage exemplified by recalibrating the transcriptomic timetree of jawed vertebrates[END_REF][START_REF] Paparella | Anatomy and evolution of the Galápagos marine iguana, Amblyrhynchus cristatus (Squamata, Iguanidae), with a new phylogeny of Iguania and considerations about aquatic adaptations in extant and extinct fossil lizards[END_REF]although Marjanović (2021) cautiously "preferred not to use Jeddaherdan to date the origin of Iguania as long as further material has not been discovered"). However, our study shows that the holotype and only known specimen of J. aleadonta is a dentary fragment of a recent (or subfossil) subadult of Uromastyx sp., which is a common lizard in the Kem Kem area today (represented by the species U. nigriventris; Wilms et al., 2009;[START_REF] Tamar | Evolutionary history of spiny-tailed lizards (Agamidae: Uromastyx) from the Saharo-Arabian region[END_REF]. Therefore, J. aleadonta can no longer be considered as the oldest known iguanian lizard from Africa, removing the only evidence for the presence of iguanians in the Mesozoic of that continent. Consequently, apart from a doubtful record from the late Palaeocene of Morocco [START_REF] Augé | Herpetofaunas from the Upper Paleocene and Lower Eocene of Morocco[END_REF], the earliest confirmed acrodontan from Africa to date is an indeterminate agamid from the late early-early middle Eocene from Algeria [START_REF] Rage | Latest Early-early Middle Eocene deposits of Algeria (Glib Zegdou, HGL50), yield the richest and most diverse fauna of amphibians and squamates reptiles from the Palaeogene of Africa[END_REF]. Regarding uromastycines, the material referred to cf. Uromastyx from the early Oligocene of Egypt represents the oldest known record from Africa [START_REF] Holmes | Agamid lizard (Agamidae: Uromastycinae) from the lower Oligocene of Egypt[END_REF]. On the other hand, molecular studies suggest that uromastycines (Uromastyx spp.) colonized Africa from Asia no earlier than the middle Miocene [START_REF] Amer | Mitochondrial DNA sequences of the Afro-Arabian spiny-tailed lizards (genus Uromastyx; family Agamidae): phylogenetic analyses and evolution of gene arrangements[END_REF][START_REF] Tamar | Evolutionary history of spiny-tailed lizards (Agamidae: Uromastyx) from the Saharo-Arabian region[END_REF].

Similarly to Jeddaherdan, Tikiguania is an Indian squamate taxon that was originally erroneously thought to be Late Triassic in age and therefore misinterpreted as the oldest known lizard [START_REF] Datta | Earliest lizard from the Late Triassic (Carnian) of India[END_REF]. Subsequently, [START_REF] Hutchinson | Tikiguania and the antiquity of squamate reptiles (lizards and snakes)[END_REF] demonstrated that this taxon is actually a late Cenozoic agamid indistinguishable from living draconines present in India (e.g. Calotes). The cases of Tikiguania and Jeddaherdan show that caution needs to be exercised when studying surface collected or screen washed vertebrate microremains that are completely free of matrix. Recent or subfossil elements can contaminate much older fossil assemblages, potentially leading to serious misinterpretations and false evolutionary and palaeobiogeographic implications.

Conclusions

According to our observations, there is so far no evidence for the presence of Iguania in the Mesozoic of Africa. We reached the conclusion that the jaw fragment from southeastern Morocco recently interpreted as belonging to a new mid-Cretaceous acrodontan taxon (Jeddaherdan aleadonta) is actually a Quaternary specimen that comes from a modern spinytailed lizard (Uromastyx sp.). This new taxonomic assignment, primarily based on the anatomical revision and reinterpretation of the specimen, is also supported by taphonomic arguments. The present study shows that Raman spectroscopy is a non-destructive and noninvasive method that can help to discriminate contaminating (i.e. much older or younger) elements within a given vertebrate fossil assemblage.

Figure 2

Acknowledgments

We are grateful to L. Bellot-Gurlet and L. Robinet for their help regarding Raman spectroscopic analyses, and L. Cazes and P. Loubry for the photographs of the dentaries of Trueman, C.N., 1999. Rare earth element geochemistry and taphonomy of terrestrial vertebrate assemblages. Palaios 14, 555-568. Wilms, T.M., Böhme, W., Wagner, P., Lutzmann, N., Schmitz, A., 2009. On the phylogeny and taxonomy of the genus Uromastyx Merrem, 1820 (Reptilia: Squamata: Agamidae: Uromastycinae) -Resurrection of the genus Saara Gray, 1845. Bonn. Zool. Beitr. 56, 55-99.

Declaration of Competing Interests

The authors declare no competing interests.

Appendix A. Supplementary data

Supplementary data to this article can be found online at

Figures captions