A guide for the identification of Spinosaurine vertebrae from the Kem Kem group, Morocco.

[MBL13]

Hello everyone,I've decided to open a chain of comments focusing on a popular theme: Moroccan spinosaurids.

This is the first comment of a small series dedicated to analyse and document the diverse morphology of spinosaurids in the Kem Kem group.

 

As an introduction,I'll be specifying how it will work,the rules and some guidance for those interested.

First and foremost,the rules:

1)For correct identifications,I require images in various view(ventral and lateral at least) and with the highest quality possible.

2)Each comment will focuse on a specific morphotype,as such,only post images of specimens matching the description giving at the start. Any specimen from other morphotype won't be identified by me.

3)Other people are encouraged to post their specimens and help with the identification/s.

 

 

Procedures:

1) A new comment will be posted each week, probably during the weekend,hour from Spain.

2) Around 4 specific comments are planed.

3) Each comment will discuss a specific morphotype (anterior cervicals,mid cervicals, posterior cervicals and cervicodorsal vertebrae).

4)At the start of each comment,I'll write a basic description of the respective morphology.

5) I'll describe in detail each vertebra contained in the four groups previously mentioned.

6) Images will be extracted/modified from the literature and complemented with additional specimens.

7) Concluding remarks: Taxonomic identification and limitations of the analysis.

8) References and acknowledgements will be posted after the main corpus of the comment is finished.

 

For any questions, please comment below. My words might not be entirely clear.I encourage everyone to post their questions.

 

Edited April 14, 2021 by MBL13

[LordTrilobite]

I've been kinda working towards a similar thing, although not exclusive to Spinosaurids.

This thread has a lot of specimens from various members and a lot of reference photos. I've also been posting 3d models there.

 

[MBL13]

I have revised the post before,but for some comparisons I need very detailed and well preserved specimens,that's the reason why I contacted some people.

I have much less material from carcharodontosaurids or abelisauroids,so I went on the relatively secure way(it's better to check a few hundreds than tenths).

[Guns]

@MBL13 This little vertebra is in my collection for quite a while . I believe it belong to Juvenile Spinosaurid caudal vertebra (?) . But would be good to hear your opinion on this.

 

location : Kem Kem basin 

Regard

Guns

 

 

[MBL13]

Indeed, a caudal vertebra from Spinosaurus:

1) The bases of the zygapophyses are very small.

2) The centrum is very elongated in ventral view,with the minimum width being little over half the posterior width.

3) The spine is broken,but the spinodiapophyseal lamina (spdl) looks well developed.

With those details in mind,I would suggest a distal caudal vertebra. The neural arch seems somewhat deflected,I would want a dorsal view to be sure about point 3.

Edited April 16, 2021 by MBL13

[MBL13]

Announcement:

The first comment was prepared for this weekend,sadly,I have a few personal issues.

It will be postponed a few days.

My apologies.

Sincerely,MBL13.

[MBL13]

First comment:

   On the Spinosaurinae vertebrae from the Kem Kem group, Morocco.

 

 The following comment is the start of a “Master-post” for those interested in the identification of Spinosaurine vertebrae from the Kem Kem group (Ibrahim et al.,2020b). I will try to summarize the current literature on the topic and elaborate a basic guide.

 In recent decades we have seen a constant interest in material from the Kem Kem group, southeastern Morocco.Spinosaurid material is among the best know,with some works focusing on general descriptions and taxonomy (Russell ,1996; McFeeters et al.,2013; Evers et al.,2015; Smyth et al.,2020), pathologies (D’Anastasio and Capasso,2004) or ontogenetic variation (Lakin and Longrich,2018). A extensive series of works have found evidence of, at least, two distinct genera and species (Russell,1996; McFeeters et al.,2013; Evers et al.,2015; Hendrickx,Mateus and Buffetaut,2016;Lakin and Longrich,2018;Arden et al.,2018,McFeeters,2021). Others on the other hand, found compelling evidence for a single species (and genus) (Ibrahim et al.,2014b,2017; Smyth et al.,2020, Ibrahim et al.,2020b).

C3

 The first identified morphology corresponds to C3.On the literature,two specimens have been found to represent such position: Wirbel “a” from BSPG 1912 VIII 19 and CMN 41768. As the first comes from the Bahariya oasis, Egypt (Stromer,1915) it won’t be discussed here. The other specimen was collected from a commercial source during the 90’s. In 1996, it was formally described by Dale Russell.C3 corresponds to A-B,C4 to C-D and C5 to E-F.

 

C4

 The C4 morphotype is as of now, poorly documented, specimens of this position are the following:

NHMUK PV R 16427 (Evers et al,2015).

NHMUK PV R 16429 (Evers et al.,2015).

FSAC-KK 5017 (Smyth et al.,2020).

FSACK-KK 5018 (Smyth et al.,2020).

ROM 65537 (McFeeters,2021).

-Smyth et al. identified Wirbel “b” from BSPG 1912 VIII 19 as C4, however, specimens from Egypt are not discussed here.

Distinguishing characters are present usually on the centrum.The following image compares the proposed C4. 

A first image compares two C4,the second includes a ventral view of C4(A-C-E) and C5 (B-D-F).

 

 

 

 

C5

 The last vertebrae of this comment are the C5, as of now, probably the best understood. Below, I present two figures comparing the variability of C5 in two similar sized specimens; then, a second figure to explain the changes in these vertebrae related with growth.

Below,there is a small comparison including BSPG 2006 I 57 (A-C) and a undescribed C5 vertebra (D-F) Several differences are present between both specimens:

 

 

 

 

 

References:

1) Stromer, 1915. Ergebnisse der Forschungsreisen Prof. E. Stromers in den Wüsten Ägyptens. II. Wirbeltier-Reste der Baharîje-Stufe (unterstes Cenoman). 3. Das Original des Theropoden Spinosaurus aegyptiacus nov. gen., nov. spec. Abhandlungen der Königlich Bayerischen Akademie der Wissenschaften Mathematisch-physikalische Klasse Abhandlung. 28(3), 1-31.

 

2) Russell, D.A. (1996). "Isolated dinosaur bones from the Middle Cretaceous of the Tafilalt, Morocco". Bulletin du Muséum National d'Histoire Naturelle, Paris, 4e série, section C 18' (2-3): 349–402.

 

3) D'Anastasio, Ruggero & Capasso, Luigi. (2011). [Post-microtraumatic cervical osteoarthritis in a cretaceus dinosaur]. Reumatismo. 56. 124-8. 10.4081/reumatismo.2004.124.

 

4) McFeeters, Bradley & Ryan, Michael & Hinic-Frlog, Sanja & Schroder-Adams, Claudia. (2013). A reevaluation of Sigilmassasaurus brevicollis (Dinosauria) from the Cretaceous of Morocco. Canadian Journal of Earth Sciences. 50. 636-649. 10.1139/cjes-2012-0129.

 

5) Ibrahim, Nizar & Sereno, Paul & Dal Sasso, Cristiano & Maganuco, Simone & Fabbri, Matteo & Martill, David & Zouhri, Samir & Myhrvold, Nathan & Iurino, Dawid. (2014). Semiaquatic adaptations in a giant predatory dinosaur. Science. 345. 10.1126/science.1258750.

 

6) Evers, Serjoscha & Rauhut, Oliver & Milner, Angela & McFeeters, Bradley & Allain, Ronan. (2015). A reappraisal of the morphology and systematic position of the theropod dinosaur Sigilmassasaurus from the “middle” Cretaceous of Morocco. PeerJ. 3. e1323. 10.7717/peerj.1323.

 

7) Hendrickx, Christophe & Mateus, Octávio & Buffetaut, Eric. (2016). Morphofunctional Analysis of the Quadrate of Spinosauridae (Dinosauria: Theropoda) and the Presence of Spinosaurus and a Second Spinosaurine Taxon in the Cenomanian of North Africa. PLoS ONE. 11. e0144695. 10.1371/journal.pone.0144695.

 

8) Ibrahim, Nizar & Zouhri, Samir & Sereno, Paul. (2017). Les dinosaures du Maroc-aperçu historique et travaux récents The Dinosaurs of Morocco – historical review and recent work.

 

9) Lakin, Rebecca & Longrich, Nick. (2018). Juvenile spinosaurs (Theropoda: Spinosauridae) from the middle Cretaceous of Morocco and implications for spinosaur ecology. Cretaceous Research. 10.1016/j.cretres.2018.09.012.

 

10) M.S.Arden, Thomas & Klein, Catherine & Zouhri, Samir & Longrich, Nick. (2018). Aquatic adaptation in the skull of carnivorous dinosaurs (Theropoda: Spinosauridae) and the evolution of aquatic habits in spinosaurus. Cretaceous Research. 93. 10.1016/j.cretres.2018.06.013.

 

11) Ibrahim, Nizar & Sereno, Paul & Varricchio, David & Martill, David & Dutheil, Didier & Unwin, David & Baidder, Lahssen & HCE, Larsson & Zouhri, Samir & Kaoukaya, Abdelhadi. (2020). Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. ZooKeys. 928. 10.3897/zookeys.928.47517.

 

12) Smyth, Robert & Ibrahim, Nizar & Martill, David. (2020). Sigilmassasaurus is Spinosaurus: A reappraisal of African spinosaurines. Cretaceous Research. 114. 104520. 10.1016/j.cretres.2020.104520.

 

13) McFeeters, Bradley. (2021). New mid-cervical vertebral morphotype of Spinosauridae from the Kem Kem Group of Morocco. Vertebrate Anatomy Morphology Palaeontology. 8. 182–193. 10.18435/vamp29370.

 

 

Edited April 25, 2021 by MBL13

[MBL13]

The comment above has been edited to remove most of the text,and the figures will be updated without any indications

My previous attempt was quite excessive,as someone reminded me. With this in mind,I'm making some changes here:

1) I'll be uploading all images soon,rather than waiting around a week between each comment.

2) No comprehensive text will be included,only a brief introduction at the start is programmed.

 

 

Edited April 25, 2021 by MBL13

[MBL13]

Second section,focusing on C6 and C7.

First image compares C5 (left column) with C6 (right column).

Second image compares three C6.

Last image compares C6 and C7(centrum),this one is hard as no described C7 is complete,and only lateral images of non described C7 are available.

References:

1) Evers, Serjoscha & Rauhut, Oliver & Milner, Angela & McFeeters, Bradley & Allain, Ronan. (2015). A reappraisal of the morphology and systematic position of the theropod dinosaur Sigilmassasaurus from the “middle” Cretaceous of Morocco. PeerJ. 3. e1323. 10.7717/peerj.1323. 

2) Smyth, Robert & Ibrahim, Nizar & Martill, David. (2020). Sigilmassasaurus is Spinosaurus: A reappraisal of African spinosaurines. Cretaceous Research. 114. 104520. 10.1016/j.cretres.2020.104520. 

 

[Le Ouistiti]

I have a vert in my collection which was identify on this forum as a possible carch dorsal, but due to the lack of pleurocoel i think it’s more like a caudal vert, maybe one of the first caudal of a spinosaurid. The problem is that i don’t have images of the posterior side of anterior caudal and my vert is flat on this side. What’s your opinion about it ?

Just now, Le Ouistiti said:

I have a vert in my collection which was identify on this forum as a possible carch dorsal, but due to the lack of pleurocoel i think it’s more like a caudal vert, maybe one of the first caudal of a spinosaurid. The problem is that i don’t have images of the posterior side of anterior caudal and my vert is flat on this side. What’s your opinion about it ?

The second and third photo is for thé posterior side And the fourth is the anterior side.

[MBL13]

An identification as an spinosaurid, specifically Spinosaurus, is a possibility. The centrum is virtually indistinguishable from the Ca4 (fourth caudal vertebra) of FSAC-KK 11888,as described by Ibrahim et al.,2020b (also see here:https://sketchfab.com/3d-models/ca4-spinosaurus-aegyptiacus-neotype-56e19d32f53043369ba23d5283279eef). Also, the condition you described (almost flat anteriorly,convex posteriorly) means the centrum is slightly amphicoelous,typical of Spinosaurus caudal centra.

However,as few caudal vertebrae from the Kem Kem group have been described in detail;it's possible that it belongs to the other species present:

As the centrum is taller than wide,and relative short;I would discard an abelisaurid proximal caudal (Méndez,2012). More posterior abelisaurid caudals are more elongated than your specimen.Thus,I don't see any affinities with abelisaurids,and noasaurids as well.

Another possibility is a proximal carcharodontosaurid caudal,but the only remains as of now documented are mostly from other positions. Nevertheless,Stromer (1931) described a proximal caudal vertebra from the,now lost,holotype of Carcharodontosaurus saharicus. I only have the translated paper without the figures,so there's little to do besides the description given by Stromer. I would like to read the description more in detail and compare your specimen later.

 

1) Stromer, E. (1931). «Wirbeltiere-Reste der Baharijestufe (unterestes Canoman). Ein Skelett-Rest von Carcharodontosaurus nov. gen.». Abhandlungen der Bayerischen Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Abteilung 9 (Neue Folge). ISSN , 1-23.

 

2) Méndez, Ariel. (2012). The Caudal Vertebral Series in Abelisaurid Dinosaurs. Acta Palaeontologica Polonica. 10.4202/app.2012.0095. 

 

3) Ibrahim, Nizar & Maganuco, Simone & Dal Sasso, Cristiano & Fabbri, Matteo & Auditore, Marco & Bindellini, Gabriele & Martill, David & Zouhri, Samir & Mattarelli, Diego & Unwin, David & Wiemann, Jasmina & Bonadonna, Davide & Amane, Ayoub & Jakubczak, Juliana & Joger, Ulrich & Lauder, George & Pierce, Stephanie. (2020). Tail-propelled aquatic locomotion in a theropod dinosaur. Nature. 581. 1-4. 10.1038/s41586-020-2190-3. 

Edited May 5, 2021 by MBL13

[Le Ouistiti]

Thanks for your message, it’s very interesting to have the publication at the end, and good job on this topic, it can perhaps help many people. 

[MBL13]

I try to "formalize" my comments adding the references below,so people can check those papers for additional information.

I hope so,it was planned very differently. I might end adding other details when they's enough time.

[MBL13]

 

Note:

The following specimens are directly taken from a series of images I'm working on now.As the original material includes around 35 vertebrae(C8-D3),in a single image,I decide to use only the described specimens.To anyone interested in those additional specimens, please send a private message.

Posterior Cervical vertebrae

As usual for spinosaurid posterior cervicals,the following vertebrae posses compact centra and low neural spines (Charig and Milner,1997;Evers et al.,2015;Smyth et al.,2020). They're easily distinguishable from more anterior vertebrae(C3-7) because of low,wide and relatively short proportions,rudimentary neural spines and well developed lateral processes.The following image includes material presented in previous formal studies,first line is BSPG 2006 I 56 representing the C8,next we have NMC 41774,BSPG 2011 115,FSAC-KK 18122 and CMN 41856 representing C9,finally,the position C10 is represented by BSPG 2006 I 53 and BSPG 2011 I 116.

Cervicodorsal Vertebrae

The following vertebrae represent the positions D1-D3,thus anterior dorsal vertebrae.They can be hard to distinguish from posterior cervicals,specially D1, because of overall similarities in proportions and comparable shape.The most notable difference with the previous vertebrae are the laterally,rather than ventrally,directed lateral processes.In D2 and D3,when the neural arch is preserved,the shape of the laminae and neural spine shape can be used to identify them appropriately. The following image contains the afromentioned positions:First line includes D1,vertebrae depicted are CMN 41857,BSPG 2006 I 54,BSPG 2006 I 55 and NHMUK PV R 16434. The second line includes NHMUK PV R 36637(here identified as a D2,not C8),NHMUK PV R 16436,NMC 41629 and FSAC-KK 5022. Position D3 is here represented by only one specimen,NHMUK PV R 16435.

 

References:

1) Charig, A. J.; Milner, A. C. (1997). "Baryonyx walkeri, a fish-eating dinosaur from the Wealden of Surrey" . Bulletin of the Natural History Museum of London. 53: 11–70.

 

2) McFeeters, Bradley & Ryan, Michael & Hinic-Frlog, Sanja & Schroder-Adams, Claudia. (2013). A reevaluation of Sigilmassasaurus brevicollis (Dinosauria) from the Cretaceous of Morocco. Canadian Journal of Earth Sciences. 50. 636-649. 10.1139/cjes-2012-0129.

 

3) Evers, Serjoscha & Rauhut, Oliver & Milner, Angela & McFeeters, Bradley & Allain, Ronan. (2015). A reappraisal of the morphology and systematic position of the theropod dinosaur Sigilmassasaurus from the “middle” Cretaceous of Morocco. PeerJ. 3. e1323. 10.7717/peerj.1323.

 

4) Ibrahim, Nizar & Sereno, Paul & Varricchio, David & Martill, David & Dutheil, Didier & Unwin, David & Baidder, Lahssen & HCE, Larsson & Zouhri, Samir & Kaoukaya, Abdelhadi. (2020). Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. ZooKeys. 928. 10.3897/zookeys.928.47517.

 

5) Smyth, Robert & Ibrahim, Nizar & Martill, David. (2020). Sigilmassasaurus is Spinosaurus: A reappraisal of African spinosaurines. Cretaceous Research. 114. 104520. 10.1016/j.cretres.2020.104520.

Edited June 19, 2021 by MBL13

[MBL13]

I decided to further add new images to this post.

As most vertebrae positions are (superficially) covered;I decided to add an image showing the different parts than can be "easily" recognized in anterior cervical vertebrae.In this case I used a C5 to made the chart. Note the IPRL (Interprezygapophyseal lamina) is not preserved however.

Thanks to @Troodon for the images of this specimen.

Some of the names in the image are abbreviations,which are explained below:

Prz: Prezygapophysis

Poz: Postzygapophysis

PRDL: Prezygodiapophyseal lamina

CDL: Centrodiapophyseal lamina

Prz facets: Facets of the prezygapophyses

SPRL: Spinoprezygapophyseal lamina

SPRF: Spinoprezygapophyseal fossa

CPRF: Centroprezygapophyseal fossa

AAF: Anterior articular facet

SPOL: Spinopostzygapophyseal lamina

SPOF: Spinopostzygapophyseal fossa

IPOL: Interpostzygapophyseal lamina

PAF: Posterior articular facet