Teeth from the Middle Jurassic of Morocco reveal the oldest turiasaurian sauropods from Africa

D. CARY WOODRUFF, PAUL M. BARRETT, DRISS OUARHACHE, ABDESSALAM EL KHANCHOUFI, KHADIJA BOUMIR, KAWTAR ECH-CHARAY, AHMED OUSSOU, RICHARD J. BUTLER, SIMON WILLS, LUKE MEADE, MIKE SMITH, and SUSANNAH C.R. MAIDMENT

Woodruff, D.C., Barrett, P.M., Ouarhache, D., El Khanchoufi, A., Boumir, K., Ech-Charay, K., Oussou, A., Butler, R.J., Wills, S., Meade, L., Smith, M., and Maidment, S.C.R. 2025. Teeth from the Middle Jurassic of Morocco reveal the oldest turiasaurian sauropods from Africa. Acta Palaeontologica Polonica 70 (3): 411–420.

Readily identifiable based on their large, “spatulate” teeth with diagnostic “heart”-shaped crowns, turiasaurians are non-neosauropodan eusauropods known from varied Jurassic and Cretaceous formations across Laurasia and Gondwana. Recently, three teeth with turiasaurian features were collected from the Middle Jurassic El Mers III Formation in the Middle Atlas Mountains of north-central Morocco. Although these teeth are superficially similar to those of the Late Jurassic Turiasaurus riodevensis from Spain, the absence of rounded denticles presence of a prominently peaked apex and a mesially flared margin, differ from other known turiasaurians. Turiasaurians have not previously been described from the El Mers III Formation, and the only named sauropod from the El Mers Group, which lacks preserved teeth, is the dubious taxon “Cetiosaurus mogrebiensis”. Due to lack of overlapping material and its lack of clear diagnostic characters, we refrain from referring these teeth to the latter, and identify them as Turiasauria indeterminate instead. These teeth represent the first definitive turiasaurian remains from Morocco, as well as the geologically oldest occurrence of Turiasauria from mainland Africa.

Key words: Dinosauria, Sauropoda, Turiasauria, teeth, Middle Jurassic, Morocco.

D. Cary Woodruff [sauropod4@gmail.com; ORCID: https://orcid.org/0000-0002-3728-134X ], Phillip and Patricia Frost Museum of Science, Miami, FL, USA; Museum of the Rockies, Bozeman, MT, USA.

Paul M. Barrett [p.barrett@nhm.ac.uk; ORCID: https://orcid.org/0000-0003-0412-3000 ], Fossil Reptiles, Amphibians, and Birds Section, Natural History Museum, Cromwell Road, London, UK; Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.

Driss Ouarhache [driss.ouarhache@usmba.ac.ma; ORCID: https://orcid.org/0000-0001-5941-0977 ], Abdessalam El Khanchoufi [abdessalam.elkhanchoufi@usmba.ac.ma; ORCID: https://orcid.org/0000-0003-2664-267X ], Khadija Boumir[khadija.boumir@usmba.ac.ma; ORCID: https://orcid.org/0000-0003-4837-5410 ], Kawtar Ech-Charay [kawtar.echcharay@usmba.ac.ma; ORCID: https://orcid.org/0000-0003-4421-4214 ], and Ahmed Oussou [ahmed.oussou@usmba.ac.ma; ORCID: https://orcid.org/0000-0001-8016-9735 ], GERA Laboratory, Faculty of Sciences Dhar El Mahraz, Université Sidi Mohamed Ben Abdellah, Fez, Morocco.

Richard J. Butler [r.butler.1@bham.ac.uk; ORCID: https://orcid.org/0000-0003-2136-7541 ] and Luke Meade [l.e.meade@bham.ac.uk; ORCID: https://orcid.org/0000-0001-7829-5193 ], School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK.

Simon Wills [s.wills@nhm.ac.uk; ORCID: https://orcid.org/0000-0002-2012-1016] and Mike Smith [Mike.Smith@nhm.ac.uk; ORCID: https://orcid.org/0009-0007-0049-9162 ], Fossil Reptiles, Amphibians, and Birds Section, Natural History Museum, Cromwell Road, London, UK.

Susannah C.R. Maidment [susannah.maidment@nhm.ac.uk; ORCID: https://orcid.org/0000-0002-7741-2500 ], Fossil Reptiles, Amphibians, and Birds Section, Natural History Museum, Cromwell Road, South Kensington, London SW7 5BD, UK; School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.

Received 10 October 2024, accepted 17 June 2025, published online 7 August 2025.

Copyright © 2025 D.C. Woodruff et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Introduction

Turiasauria is a clade of large-bodied non-neosauropod eusauropods ranging from the Early or Middle Jurassic to the Early Cretaceous (Royo-Torres et al. 2006; Mocho et al. 2016; Mannion 2019; Royo-Torres et al. 2021). First identified from the Iberian Peninsula (Royo-Torres et al. 2006) and originally restricted to former Laurasian continents (Britt et al. 2017; Royo-Torres et al. 2017), Turiasauria is now known from various locations in Africa (Mocho et al. 2016; Mannion et al. 2019; Royo-Torres et al. 2021), India (Sharma et al. 2022) and perhaps Argentina (Royo-Torres et al. 2021; Milàn and Mateus 2024). Recent identification of an Early Jurassic putative turiasaurian tooth from Denmark (Milàn and Mateus 2024) indicates that the group may have originated by that time, achieving a wider distribution by the Middle Jurassic (Royo-Torres et al. 2021; Scharma et al. 2022).

Until now, the African record of Turiasauria has consisted of two named taxa from the Middle Jurassic Isalo III Formation of Madagascar (Narindasaurus, Royo-Torres et al. 2021) and the Upper Jurassic Tendaguru Formation of Tanzania (Tendaguria, Mannion et al. 2019), although isolated teeth from the Middle Jurassic of Niger and Mada­gascar and the Early Cretaceous of Libya have also been referred to the clade (Mocho et al. 2016). Xing et al. (2015) suggested that the Middle Jurassic Moroccan sauropod Atlasaurus formed a clade with the turiasaurians Losillasaurus and Turiasaurus, but this result has not been replicated, and Atlasaurus is more commonly thought to be a brachiosaurid (e.g., Mannion et al. 2019; Royo-Torres et al. 2021). Here, we report three associated sauropod teeth from the Middle Jurassic El Mers III Formation of the Middle Atlas Mountains, Morocco, which represent the earliest definitive record of turiasaurians in Africa.

The Bathonian El Mers III Formation, which crops out in exposures around the town of Boulemane in the Middle Atlas Mountains, is becoming increasingly important for understanding the radiation of dinosaurs during the Middle Jurassic. Dinosaur remains from the formation include the world’s oldest ankylosaur, and the first from Africa, Spico­mellus afer (Maidment et al. 2021), the early stegosaurs Adratiklit boulahfa (Maidment et al. 2020) and Thyreosaurus atlasicus (Zafaty et al. 2024), and the world’s oldest cerapodan ornithischian (Maidment et al. 2025). The formation therefore hosts some of the earliest representatives of several major ornithischian dinosaur clades, shedding light on dinosaur diversifications and radiations in the aftermath of the global environmental perturbations that marked the end of the Early Jurassic (Cabreira et al. 2016; Reolid et al. 2022; Maidment et al. 2025).

Institutional abbreviations.—FHPR, Utah Field House of Natural History State Park Museum, Vernal, Utah, USA; MAP, Museo Aragonés de Paleontología, Teruel, Spain; ML, Museu da Lourinhã, Lourinhã, Portugal; MNHN, Muséum national d’Histoire naturelle, Paris, France; NHMD, Natural History Museum of Denmark, Copenhagen, Denmark; RAJ, Geological Survey of India, Kolkata, India; UMNH Natu­ral History Museum of Utah, Salt Lake City, Utah, USA; USMBA, Université Sidi Moha med Ben Abdellah, Fez, Morocco.

Material and methods

The specimens described herein are three teeth (USMBA 002–004) that were surface collected from the Bathonian El Mers III Formation at the Boulahfa Plain, near Boulemane in the Middle Atlas Mountains, Morocco (see Maidment et al. 2020 for locality data). On the Boulahfa Plain, the El Mers III Formation is exposed in erosive badlands formed by frequent flash flood events. This flash flooding transports large amounts of sediment, and in situ bones are frequently exposed and re-buried by these bulk transport events. The teeth were surface-collected by a local farmer in close proximity to large limb and other elements that were subsequently re-buried under at least 5 m of sediment during a flash-flooding event before excavation was possible. The El Mers III Formation at the Boulahfa Plain is composed of variegated mudstones and sparse, laterally discontinuous sandstones, and is predominantly greenish in its lower parts and purple-reddish in its upper parts (Maidment et al. 2020). The zone from which most of the fossils appear to be derived is close to the top of the greenish section and is around 20 m thick (Maidment et al. 2020: fig. 3). The site where the teeth were collected, which we refer to as the “Big Flood Quarry”, is located approximately 15 m below the colour-change from predominantly green to predominantly purple-red mudstones.

Teeth were photographed and measured using standard documentation techniques. Tooth anatomical terminology follows that of Smith and Dodson (2003) and Hendrickx et al. (2015).

Results

Description.—According to Royo-Torres et al. (2021), isolated turiasaur teeth can be assigned approximate locations in the skull based on the orientation of the crowns. In premaxillary and maxillary teeth, in mesial or distal orientation, the crown is curved lingually. In dentary teeth, the crown is angled “labially” (Royo-Torres et al. 2021), although it would be more accurate to describe them as straight, or apically oriented, as the crown apex is not labially inclined. Applying these criteria, USMBA 002 and 004 are from the premaxilla or maxilla, and from the distal orientation of the crown apices, likely from the right side. Because of the large wear facets, tooth USMBA 003 is more challenging to place. In mesial and distal orientation, the undulating crown does not appear to curve strongly lingually, suggesting that this may be a dentary tooth, from the right side also. Measurements of the teeth are provided in Table 1.

All three teeth include a substantial portion of the root and two of the crowns are well-preserved (Fig. 1). The crowns of USMBA 002 and 003 are truncated by wear facets, heavily in the case of USMBA 003, but USMBA 004 is unworn. The crown surfaces have been polished by wind and/or water action, but the enamel texture is still clearly visible on tooth USMBA 004 and is partially visible in patches on USMBA 002 and 003. USMBA 002 and 003 are consistent in morphology and are described together for convenience, whereas USMBA 004 differs in shape and is described separately. Based on their relative sizes and different degrees of crown expansion, it seems likely that teeth USMBA 002 and 003 are from the distal ends of the tooth row, whereas tooth USMBA 004 was likely more anteriorly or centrally located.

In labial view, the tooth crowns of USMBA 002 and 003 exhibit slight mesiodistal expansion with respect to the root. Maximum mesiodistal expansion occurs at a point only a few millimetres apical to the root / crown boundary and is developed to similar degrees either side of the crown long axis. Apical to the maximum diameter, the crown tapers to a bluntly rounded terminus. The mesial crown margin is smoothly and gently convex apicobasally, whereas the distal margin is sinuous, being slightly convex basally, but more strongly concave apically. As a result, the crowns are asymmetrical in labial view, and the tooth apex is recurved distally. Overall, these features give the crowns a narrow, heart-shaped outline. The labial surface is strongly convex mesiodistally with a slight break-in-slope near to the distal margin due to the presence of an incipient distal groove. Most of the surface is smooth, but small unpolished patches wear “wrinkled” enamel showing evidence of connected, anastomosing ridges.

In lingual view, the crowns are gently concave mesiodistally and this, in combination with the labial convexity, gives them a strongly D-shaped transverse cross-section. The central part of the lingual convexity is occupied by a low eminence, in a position equivalent to the lingual ridge of many other sauropods. This feature extends apically toward the crown tip and divides the lingual surface into two subequal parts.

In mesial or distal view, the labial crown surfaces are strongly convex apicobasally, whereas the lingual surfaces are strongly concave. The crown apex is lingually inclined.

As preserved, the crown margins of USMBA 002 and 003 lack denticles. The tip of USMBA 002 is truncated by a narrow, high-angled, elliptical wear facet that is apicobasally longer than transversely wide (width is c. 1/2 the length) and extends along the mesial crown margin for a short distance. A very narrow, apicobasally elongate (width is c. 1/3 the length) wear facet is present on the distal margin but does not extend apically to merge with the mesial facet. USMBA 003 is more heavily worn, with large, high-angled, apicobasally ovoid wear facets that have truncated the entire mesial and distal margins and that are confluent around the crown apex. However, although extensive, the wear has not led to the development of the distinctive “shoulders” seen in some other worn sauropod teeth (e.g., Camarasaurus spp.; Upchurch and Barrett 2000). In both cases, the wear facets reveal that the enamel is thin and symmetrically distributed around the tooth crown.

USMBA 004 is similar to the other teeth in many respects, but its crown is much more strongly expanded mesiodistally with respect to the root, in labial view, and the curvature of its mesial and distal margins is correspondingly greater, giving it a much more obviously heart-shaped outline. The expansion is more strongly asymmetrical in this tooth, with most occurring mesial to the crown long-axis. The labial surface is strongly convex mesiodistally, due to the presence of a prominent, centrally positioned, apicobasally extending swelling, which is defined both mesially and distally by incipient grooves. In lingual view, an incipient lingual ridge is present, but is limited to the apical-most part of the tooth. Wear facets and denticles are both absent. The crown surface is better preserved than in USMBA 002 and 003 and an anastomosing pattern of enamel wrinkles covers most of the crown surface.

The slenderness index (SI) of the crowns, the ratio of apicobasal length to mesiodistal width (Upchurch 1998), ranges from 1.56 (USMBA 003, although this is likely an underestimate due to heavy wear), through 1.63 (USMBA 004) to a maximum of 1.69 (USMBA 002). A second ratio, the compression index (CI), defined as crown maximum labiolingual width divided by crown mesiodistal width (Díez Días et al. 2013), varies from 0.45 (USMBA 004), through ~0.6 (USMBA 003) to 0.68 (USMBA 002).

In all three teeth, the root has a sub-circular, cylindrical cross-section and is broken basally to expose the pulp cavity.

Comparisons.—The three teeth from the Boulahfa Plain, especially USMBA 002 and 004, are strikingly similar to previously documented turiasaurian teeth. The elongate, tapered crown apex present in USMBA 004, is likewise seen in Losilla­saurus giganteus (Royo-Torres et al. 2021), Turia­saurus riodevensis (Royo-Torres and Upchurch 2012), isolated upper Kimmeridgian to basal Tithonian teeth from Portugal (Mocho et al. 2016), and an isolated Pliensbachian tooth from Denmark (Milàn and Mateus 2024). The mesio­distal widths of the crowns, especially the degree of mesodistal expansion of USMBA 002 and the mesiodistal expansion along USMBA 004 is similarly seen in L. giganteus (from Royo-Torres et al. 2006), T. riodevensis (from Royo-Torres and Upchurch 2012), isolated teeth from the upper Kimmeridgian to basal Tithonian of Portugal (Mocho et al. 2016), an isolated Bathonian tooth from India (Sharma et al. 2022), and the isolated Pliensbachian tooth from Denmark (Milàn and Mateus 2024).

In terms of their overall morphology, the Boulahfa Plain teeth are most similar to those from T. riodevensis. By contrast, many of the maxillary teeth in L. giganteus have a stronger degree of apex distal curvature, and its mesial and distal wear facets are almost shelf-like, with some facets having peaked apices themselves. These features are not observed in the Boulahfa Plain teeth. Unlike in either L. giganteus or T. rio­devensis, there are no rounded denticles along the mesial apex boundary. As in T. riodevensis, the apex of the crown of USMBA 004 is relatively apicobasally straight with a low degree of apical curvature (Royo-Torres and Upchurch 2012). The labial groove on the mesial side has a c. 4 mm depressed region, and along with the convex mesial edge, the crown morphology of USMBA 004 is much more mesiodistally “flared” than known turiasaurian examples (i.e., T. riodevensis, L. giganteus; Fig. 2).

Discussion

Systematic position.—The Boulahfa Plain teeth possess a series of diagnostic features that permit referral to Eusauropoda, including: tooth crowns with D-shaped cross-sections; a lingual concavity bearing an incipient lingual ridge; and high-angled mesial and distal wear facets (Upchurch 1998; Wilson and Sereno 1998; Wilson 2002; Upchurch et al. 2004). The presence of incipient mesial and distal labial grooves, as well as extensive areas of anastomosing enamel wrinkles, are also consistent with eusauropod affinities (Upchurch 1998; Wilson and Sereno 1998; Wilson 2002; Upchurch et al. 2004) although these features first appear in the early diverging non-eusauropod Pulanesaura eocollum (McPhee and Choiniere 2018), which is close to sauropod origins.

Among eusauropods, heart-shaped crowns in labial/lingual view are characteristic of Turiasauria, enabling referral of the Boulahfa Plain teeth to this clade (Royo-Torres et al. 2006; Mocho et al. 2016). A second possible turiasaurian synapomorphy, the presence of elongate apicobasal grooves along the root (Royo-Torres et al. 2021), is not present in any of the teeth from the Boulahfa Plain, although the root of USMBA 004 possesses ambiguous traces of what might be grooves. However, it is possible that this feature diagnoses a subset of later-occurring turiasaurians and was absent in earlier diverging taxa.

Several other features of the Boulahfa Plain teeth have systematic significance. Their low SI values (1.56–1.69) exclude them from Titanosauria and Diplodocoidea (which have SI >4.0; e.g., Upchurch 1998; Upchurch et al. 2004). The CI values (0.45–0.68) for the Boulahfa Plain teeth are lower than those reported for titanosaurians (~0.7–1.1; Díez Díaz et al. 2013; Holwerda et al. 2018). The absence of denticles (in USMBA 004) is consistent with referral to Eusauropoda (e.g., Upchurch 1998) but does not help to classify the teeth more precisely, as denticles are retained in multiple non-­diplodocoid and non-titanosaurian lineages, such as mamenchisaurids and early diverging macronarians (e.g., Wilson and Sereno 1998; Upchurch et al. 2004), suggesting substantial homoplasy in denticle loss.

The Moroccan sauropod record.—Named sauropod dinosaurs from Morocco consist of the Early Jurassic vulcanodontid Tazoudasaurus naimi (Allain et al. 2004), the Middle Jurassic taxa Atlasaurus imelakei (Monbaron et al. 1999; Xing et al. 2015; Royo-Torres et al. 2021) and “Cetiosaurus mogrebiensis” (de Lapparent 1955), and the early Late Cretaceous rebbachisaurid Rebbachisaurus garasbae (Lavocat 1954; Wilson and Allain 2015). However, indeterminate Early to Middle Jurassic and Late Cretaceous teeth (Holwerda et al. 2018), postcranial material (Pereda-Suberbiola et al. 2004; Mannion and Barrett 2013; Ibrahim et al. 2016; Nicholl et al. 2018; Holwerda 2020) and trackways (Termier 1942; Dutuit and Ouazzou 1980; Jenny et al. 1981; Hadri et al. 2007; Belvedere 2008; Marty et al. 2010; Enniouar et al. 2014; Lallensack et al. 2018; Oukassou et al. 2019; Boutakiout et al. 2020; Oussou et al. 2023) are also documented.

Although the teeth from the Boulahfa Plain are referrable to Turiasauria, it is useful to compare them to the teeth associated with other named Moroccan taxa. They can be distinguished from those of Tazoudasaurus naimi, as the latter has almost symmetrical tooth crowns in labial view, which lack the heart-shaped outline of turiasaurians (Allain and Aquesbi 2008). Moreover, the teeth of T. naimi bear marginal denticles (Allain and Aquesbi 2008). The holotype of Rebbachisaurus garasbae does not include teeth (Lavocat 1954; Wilson and Allain 2015) but isolated teeth from the early Late Cretaceous of Morocco have been referred to Rebbachisauridae (e.g., Holwerda et al. 2018). These referred teeth are elongate, peg-like and cylindrical, differing substantially from those of turiasaurians. Of perhaps more relevance, the Middle Jurassic taxon Atlasaurus imelakei has been recovered as a turiasaurian in some recent analyses (Xing et al. 2015) and its holotype includes teeth (Monbaron et al. 1999: fig. 1f, g). In A. imelakei the crowns are mesiodistally narrow, lack a heart-shaped outline and some possess denticles, suggesting that the teeth from the Boulahfa Plain are a distinct taxon, although they are near contemporaries. Moreover, A. imelakei is usually recovered as an early diverging macronarian in most analyses (e.g., Monbaron et al. 1999; Royo-Torres et al. 2021) so it is not closely related to turiasaurians.

“Cetiosaurus mogrebiensis”, is a problematic taxon of uncertain phylogenetic affinity that is currently considered to be a nomen dubium (Upchurch et al. 2004). Named by Albert-Félix de Lapparent in 1955, this species was described from three partial skeletons collected from different localities within a c. 3 km radius of the town of El Mers, which is about 20 km northeast of Boulemane. No teeth are known for “Cetiosaurus mogrebiensis”, so it is not possible to compare the specimens described herein directly. Although de Lapparent (1955) noted similarities between “C. mogrebiensis” and the “cetiosaurids” Bothriospondylus spp. and C. oxoniensis, and Läng and Mahammed (2010) recovered it within a polytomy of “cetiosaurid” eusauropods, Upchurch and Martin (2003) noted that comparisons to “cetiosaurids” were untenable due to the absence of phylogenetically informative characters in the material of “C. mogrebiensis” and several notable anatomical differences between the latter and C. oxoniensis. As a result, they noted that the Moroccan and UK species were unlikely to be congeneric (Upchurch and Martin 2003; Upchurch et al. 2004). Redescription of the “C. mogrebiensis” material is needed to determine its systematic position and to test its taxonomic validity. If “C. mogrebiensis” is found to be a turiasaur, the Boulahfa Plain teeth could conceivably be referred to it (despite lack of overlapping material), but in the absence of any such evidence, we refrain from making any referrals herein.

The oldest turiasaur from Africa.—Occurrences of Turia­sauria in both Gondwana and Laurasia indicate that the clade achieved a wide distribution by Bathonian times, as shown by their presence in the Middle Jurassic of India (Sharma et al. 2022), Madagascar (Royo-Torres et al. 2021), Morocco (this paper) and the UK (Barrett 2006, 2021; Royo-Torres et al. 2021; Fig. 3). Turiasaurian taxa are better known from the Upper Jurassic, with representatives from Portugal (Zby), Spain (Losillasaurus, Turiasaurus), Switzerland (Amanzia), and Tanzania (Tendaguria), and the clade persists into the Lower Cretaceous (Moabsaurus, Mierasaurus), at least in North America and Europe (e.g., Britt et al. 2017; Royo-Torres et al. 2017; Mannion 2019; Fig. 3). If a tooth from the Hasle Formation of Denmark is not allochthonous, then the record of Turiasauria begins in the Early Jurassic (Pliensbachian), c. 17 million years earlier than thought previously (Milàn and Mateus 2024). Additionally, both Royo-Torres et al. (2021) and Milàn and Mateus (2024) suggested that the teeth of Bagualia alba from the Toarcian of Argentina (Pol et al. 2020: fig. 2f) were similar to those from turiasaurians, which would suggest a global radiation of the clade by the mid- to late Early Jurassic. However, Bagulia has not been recovered as a turiasaurian in any phylogenetic analysis and it is usually regarded as an early diverging eusauropod (Pol et al. 2020; Gomez et al. 2021, 2024). Moreover, most of the teeth referred to this taxon (e.g., Pol et al. 2020: fig. 2g) are much more similar in shape to those of other early sauropods, such as Tazoudasaurus and Pulanesaura, with relatively narrow, denticulate crowns. Although one figured tooth of Bagualia is superficially heart-shaped, this morphology might be due to differential wear of the crown margins (such as variable wear within the tooth row; Holwerda et al. 2015; Wiersma and Sander 2017; Régent et al. 2024) rather than representing its original shape.

Isolated teeth from the Middle Jurassic of Niger (de Lapparent 1960) and Madagascar (Läng 2008), as well as the Lower Cretaceous of Libya (Le Loeuff et al. 2010), have been referred to Turiasauria (Mocho et al. 2016). However, in the case of the tooth from Niger, the apical part of the crown lacks the distinctive strongly convex distal margin that gives turiasaurians their distinctive heart-shaped morphology (Mocho et al. 2016: fig. 10f), while the teeth from Madagascar (Mocho et al. 2016: fig. 10g) and Libya (Le Loeuff et al. 2010: fig. 5) are too incomplete to determine if they were originally heart-shaped or not; although the Libyan teeth possess the synapomorphic apicobasal grooves (Royo-Torres 2021). As a consequence, all these referrals should be regarded with caution, with Mannion (2019) suggesting that these earlier reports of putative African “turiasaurian” teeth should be regarded as Sauropoda indet. (see Poropat et al. 2022 for a review of the taxonomic interpretations of this tooth).

Sereno et al. (1999) noted that the teeth of Jobaria tiguidensis are spatulate and variably denticulated along their mesial and distal margins (Sereno et al. 1994: fig. 4); and while the cross-sectional morphology of the crown was not figured nor discussed, the labial/lingual morphology is strongly reminiscent of Losillasaurus, Turiasaurus, and other turiasaurs (Fig. 2). However, while the teeth of Jobaria appear to be similar to those of turiasaurs, and the prefrontal and quadratojugal of Jobaria has been noted to be similar to Turiasaurus (Royo-Torres and Upchurch 2012), no phylogenetic analyses have recovered Jobaria within Turiasauria (Upchurch et al. 2004; Remes et al. 2009; Chure et al. 2010). Likewise, teeth bearing turiasaur-like morphologies are associated with new specimens of Haplocanthosaurus sp., which could potentially challenge the traditional phylogenetic position of this taxon (DCW and John Foster, personal observation 2024). However, as with Jobaria, no phylogenetic analyses have recovered Haplocanthosaurus within Turiasauria. Potentially, convergence could explain the dental similarities in these taxa, and examinations using dental indices (e.g., Frauenfelder et al. 2024) might help to elucidate their taxonomic position in the future.

By contrast, the Boulahfa Plain teeth show clear evidence of turiasaurian affinities and thus represent the oldest record of the clade from mainland Africa, as well as the first definitive record of the clade from North Africa. They are close in age to Narindasaurus from the Isalo III Formation of Madagascar (Middle Jurassic, Royo-Torres et al. 2021) and pre-date the Late Jurassic (Tithonian) record of Tendaguria from Tanzania (Mannion et al. 2019). The Boulahfa Plain teeth expand the geographic range of the clade during the Middle Jurassic, and together with the material from Madagascar and the possible record from the Pliensbachian of Denmark (Milàn and Mateus 2024) they imply that the initial spread of the clade occurred at some point in the late Early Jurassic.

Conclusions

The three Boulahfa Plain sauropod teeth represent the first definitive turiasaurian remains from Morocco, as well as earliest record of Turiasauria from mainland Africa. As previously demonstrated by the co-occurring ankylosaur Spicomellus afer and the stegosaurs Adratiklit boulahfa and Thyreosaurus atlasicus the Middle Jurassic El Mers III For­mation of Morocco is vitally important for documenting the early radiation and biogeographic history of many dinosaurian clades.

Although palaeontological exploration in the El Mers III Formation is in its early stages, so far, its dinosaur fauna consists of two stegosaurs, an ankylosaur, an early-diverging cerapodan, and a turiasaur. A similar faunal composition is observed in various Late Jurassic faunas globally, for example: from the Tendaguru Formation of southeastern Tanzania, from the Lourinhã Formation of western Portugal, possibly even from the Morrison Formation of the western United States, and from the Villar del Arzobispo Formation in eastern Spain (Campos-Soto et al. 2019). Middle Jurassic terrestrial faunas are globally poorly represented (Maidment et al. 2020), making the fauna of the El Mers III Formation critical to our understanding of the establishment of these famous Late Jurassic faunas.

Acknowledgements

Rafael Royo-Torres (University of Zaragoza, Spain), Alessandro Chiarenza (University College London, UK), and Archana Sharma (Geological Survey of India, Kolkata, India) provided relevant literature, Rafael Royo-Torres (University of Zaragoza, Teruel, Spain) and Pedro Mocho (Instituto Dom Luiz Lisbon, Portugal) additionally provided their turiasaurian guidance and expertise. Finally, thanks to handling editor Daniel Barta (Oklahoma State University, Tahlequah, USA), Femke Holwerda (Utrecht University, The Netherlands), and an anonymous reviewer for their constructive comments. Thanks to the donors of Frost Science’s Paleontology Department which enabled DCW to participate in the joint expeditions of the NHM, USMBA, and University of Birmingham. Funding for these expeditions is provided by the British Institute of Libyan and North African Studies and the NHM’s Science Investment Fund.

Editor: Daniel Barta

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Acta Palaeontol. Pol. 70 (3): 411–420, 2025

https://doi.org/10.4202/app.01214.2024