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Moroccan Mosasaurs


jnoun11

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Hello. I'd just like to contribute this specimen to the conversation. It is one of the undescribed Moroccan tylosaur teeth. Hopefully, a study will come out on it soon so that it can be identified. 

 

Tylo.jpg.9ed565475c36cf5f1fa0f1c8ed1011f2.jpg

601862e4e24a1_tylo(2).jpg.715aeeeae7e61c4d409d7c633717b0b2.jpg601862e57f42a_tylo(3).jpg.22ffba9dfdf0406fd9a74e6138b2c156.jpg

601862e6123bb_tylo(4).jpg.a0070c3f6d861caaca62c22c913b4c78.jpg601862e6a45fb_tylo(5).jpg.e22c4271da7923841cf9cad29eae2dad.jpg

 

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50 minutes ago, Praefectus said:

Hello. I'd just like to contribute this specimen to the conversation. It is one of the undescribed Moroccan tylosaur teeth. Hopefully, a study will come out on it soon so that it can be identified. 

 

Tylo.jpg.9ed565475c36cf5f1fa0f1c8ed1011f2.jpg

601862e4e24a1_tylo(2).jpg.715aeeeae7e61c4d409d7c633717b0b2.jpg601862e57f42a_tylo(3).jpg.22ffba9dfdf0406fd9a74e6138b2c156.jpg601862e6123bb_tylo(4).jpg.a0070c3f6d861caaca62c22c913b4c78.jpg601862e6a45fb_tylo(5).jpg.e22c4271da7923841cf9cad29eae2dad.jpg

 

Beautiful specimen, indeed!

 

Since the discussion has turned to the undescribed tylosaurid(s) of Morocco, let me add the below specimens as evidence for their presence in the Ouled Abdoun Basin. For, though mosasaurian heterodonty leaves some space discussion as to attribution of teeth to one or the other genus, the below rostra exhibit the unmistakable tylosaurian character of a premaxilla that protrudes past the teeth.

 

60186c893f767_Tylosauruscf.Hainosaurussp.rostrumOuledAbdounMorocco01.thumb.jpg.8257da9bfe89f8db9920108c2ef81e4d.jpg60186c8a88987_Tylosauruscf.Hainosaurussp.rostrumOuledAbdounMorocco02.thumb.jpg.e64105dbfc7611c602fd985a21f9ab29.jpg60186c8bde90d_Tylosauruscf.Hainosaurussp.rostrumOuledAbdounMorocco03.thumb.jpg.8b4bbc53dfc7553d5eb061c4e7b40afe.jpg60186c8d488d2_Tylosauruscf.Hainosaurussp.rostrumOuledAbdounMorocco04.thumb.jpg.9902b55e6338ba047d4f66893676d5c1.jpg

 

60186df87354d_MoroccanTylosaurrostrumdentary01.jpg.89d3d5739a6c0070ba67b08388d5aef3.jpg60186df941d43_MoroccanTylosaurrostrumdentary02.jpg.0cb3ff6e4934a17e3751e21d926ba73a.jpg60186dfa0b0c4_MoroccanTylosaurrostrumdentary03.jpg.5092ebb555d537d404467f122ff2c24b.jpg60186dfabf742_MoroccanTylosaurrostrumdentary04.jpg.593505359203807bd0aad4f36cc8ac21.jpg

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'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett

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Xenodens calminechari gen. et sp. nov., a bizarre mosasaurid (Mosasauridae, Squamata) with shark-like cutting teeth from the upper Maastrichtian of Morocco, North Africa

Can someone send me this publication? thanks in advance.

 

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@Egempaleo, unfortunately I can't help you with the article, as it's paywalled (though I'd be much interested in it myself). But there's some additional discussion on this new species going on in this thread:

 

 

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  • 1 month later...

In light of mosasaur week and because I "promised" @Calcanay I would, here's a report on some investigation I did on Prognathodon solvayi, originally posted on the Dutch forum here.

 

It all started with me wanting to know how to differentiate between the teeth of Mosasaurus beaugei and P. solvayi, as all teeth I had seen ascribed to either species at that point seemed extremely similar to me. The answer I got was the expected "you can't tell without having skull material, especially the quadrate, because mosasaurs have heterodont dentition". In addition, however, I was also told that M. beaugei teeth are faceted, whereas the teeth of P. solvayi are striated or ribbed and are somewhat reminiscent of Gavialimimus almaghribensis (previously Platecarpus ptychodon). This didn't help me too much further, though, as the term striae kind of confused me into thinking along the lines of pliosaur tooth ornamentation, and the ornamentation of G. almaghribensis didn't seem to quite match the bill either.

 

The diagram presented as figure 3 in Hornung and Reich (2014), reproduced (with annotation) below, goes a long way in clarifying the different terms used in tooth morphology as applied to mosasaurs. It also illustrates the deceptive similarity between simple striations and facetting, as the two appear to go hand-in-hand and can be difficult to discern when not looking at a cross-section of a tooth.

 

urn-cambridge.org-id-binary-20170308045703739-0304-S0016774614000316-S0016774614000316_fig3g.jpeg.f1281256fef934baa4306baebb272e4e.jpeg"Terminology of enamel structures and tooth crown geometries adopted in this paper. A, Striation hierarchy and patterns (on a schematic enamel surface): 1, primary and secondary striae; 2, primary stria bifurcating adapically into secondary stria, tertiary striae at the base; 3, primary and tertiary striae; 4, primary stria converging adapically with secondary stria; 5, primary stria anastomosing into secondary stria, tertiary striae at the base. B–G, Polygonal cross-sections and concave linear features (schematic cross sectional quadrant of tooth crown): B, simple striations; C, convex prism faces; D, flat prism faces; E, concave facets superimposed to prism faces; F, concave facets; G, flat-bottomed facets."

 

 

 

 

Once I found out that the holotype specimen for P. solvayi (IRSNB R33) is kept at the Museum voor Natuurwetenschappen in Brussels, however, I planned a trip to go and inspect it myself. This impressive museum doesn't just house the iconic Bernissart iguanodons, but also has a room dedicated to mosasaurs, with multiple holotype specimens on display. I made use of my visit and took plentiful reference photographs, but in particular of P. solvayi, which are reproduced below. Please note therefore that the below images are not of a Moroccan mosasaur, but rather one that was found in Belgium (Solvay-quarry at Mesvin, near the town of Ciply)! For Moroccan material, please keep reading, however.

 

IMG_10115_resize_86.thumb.jpg.959a088d37a501a19ad5161a7c2d02d8.jpgIMG_10096_resize_63.thumb.jpg.6ff326f43aac715d23b09c62c8a0c9f4.jpgIMG_10100_resize_85.thumb.jpg.74e5197ed673bc256c4d96e51e266ea5.jpgIMG_17921_resize_27.thumb.jpg.4c9f79015bc02fe2dfd7ade6c1df93ee.jpg

 

IMG_10116_resize_61.thumb.jpg.b0bf343464cf29fda61a951163b2b708.jpgIMG_17927_resize_90.thumb.jpg.b5acf0c9a47fd24a02d524303401ba7e.jpgIMG_17929_resize_89.thumb.jpg.99dee13ed94f709857f8f284a7c1665a.jpgIMG_10092_resize_43.thumb.jpg.26800aec872cbed74d135cee5f5d3eff.jpg

 

IMG_10118_resize_39.thumb.jpg.d9f7dbbb364039cc848675df3f864f93.jpgIMG_10086_resize_24.thumb.jpg.04fc9a5d836be7d7e4e17c4ce043c2ca.jpg

 

Lingham-Soliar and Nolf (1989) describe these teeth as follows (p. 144):

Quote

The teeth are large, mostly uniform in size with the most anterior and posterior ones more strongly posteriorly recurved. In addition the first and perhaps the second maxillary teeth are procumbent [...]. Teeth towards the centre of the tooth row are more vertical when compared with those of the anterior and posterior part of the dental ramus, triangular in lateral configuration and generally more rugged. The tooth crowns possess strong vertical striae, unlike those of Prognathodon giganteus and P. overtoni (SDSM 3393) which have smooth enamelled surfaces.

[...]

The premaxillary teeth are unique for the genus in their highly procumbent disposition, with only Prognathodon giganteus and FMNH PR 165, a specimen referred to Prognathodon sp. by RUSSELL (1970), showing some degree of this character. The premaxillary teeth are oriented such that the carinae are laterally and medially directed with the lingual surface approximately a third of the buccal surface.

 

This coincides well with my own observations of the above specimen - and indeed with the description of features that distinguish M. beaugei from P. solvayi I was given initially (though much hinges on being able to properly tell striations from facets). Generally, I find the teeth of P. solvayi to have a rather tall and slender triangular shape in the lateral, with mild labiolingual compression and slight lingual and distal curvature. Teeth are ornamented with thick striae that may be called ribs, with an about equal number of striations occurring on both sides of the tooth (in contrast, M. beaugei has facets, with the higher density on the lingual versus the bucal side). Carinae are present on both the anterior and posterior edges of the teeth. Tooth shape changes towards the back as well as towards the front of the jaw, with those towards the back becoming forshortened with increased distal curvature, while those towards the front of the jaw - and especially on the premaxilla - are more slender and conical in shape.

 

That having been said, I've only ever seen a single tooth that matches these characteristics, which was at the Sainte Marie-aux-Mines mineral & gem fair, now almost two years ago. The tooth might be familiar to @jnoun11, as the seller validated the tooth's identification by stating his confirmation of the ID. It is indeed morphologically very similar to the Brussels specimen, with my guess being it's a premaxillary tooth, or otherwise one of the very frontmost maxillary ones. The striations are much more prominent in this Moroccan specimen, however, and indeed seem more like ribbing if not enamel folds. In addition, whereas the enamel on the holotype specimen seems overall smooth, that of this specimen seems roughened, with the crown apex even exhibiting anastomosing ridgelets recalling the surface texture of durophagous mosasaurs. Size was about 2.5 cm for the crown and 3 cm for the root.

 

20210330_224536_resize_33.thumb.jpg.c5cf33445d41d77628606456bb2dec1b.jpg20210330_224813_resize_46.thumb.jpg.713be2c85564a2280836a1756ddbd0fd.jpg20210330_224618_resize_5.thumb.jpg.c79fa485e1fd6c5f35e29e20c88853e0.jpg20210330_224637_resize_79.thumb.jpg.077f6531590d879cc636c7bf208f661d.jpg20210330_224734_resize_33.thumb.jpg.7a129d60d6ac12627ec9738f6fd3f57e.jpg

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'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett

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  • 3 weeks later...
On 2/1/2021 at 2:22 PM, Praefectus said:

Hello. I'd just like to contribute this specimen to the conversation. It is one of the undescribed Moroccan tylosaur teeth. Hopefully, a study will come out on it soon so that it can be identified. 

 

 

Tylo.jpg.9ed565475c36cf5f1fa0f1c8ed1011f2.jpg.c5f857144b139d7f033ae15c12093bfe.jpg

 

 

 

Quick correction. This tooth is not tylosaurine. It is Mosasaurus.

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4 hours ago, Praefectus said:

Quick correction. This tooth is not tylosaurine. It is Mosasaurus.

 

Mind sharing with us what changed your opinion? ;)

'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett

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2 hours ago, pachy-pleuro-whatnot-odon said:

 

Mind sharing with us what changed your opinion? ;)

 

I've been reading up on mosasaurs and it seems like most (maybe all) of the species of Tylosaurus have tertiary striae along their teeth. The smooth enamel on this tooth was the first sign that my earlier identification was incorrect. 

 

I did a bit more reading and found that teeth from Mosasaurus possess the following traits:

  • Posterior and medial recurve 
  • Two prominent carinae bearing light serrations
  • Asymmetrical labial and lingual surfaces (lingual inflated) 
  • Labial (lip facing) surface flattened
  • Lingual (tongue facing) surface convex
  • Crown with U-shaped cross-section 

 

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4 hours ago, Praefectus said:

I've been reading up on mosasaurs and it seems like most (maybe all) of the species of Tylosaurus have tertiary striae along their teeth. The smooth enamel on this tooth was the first sign that my earlier identification was incorrect. 

 

I did a bit more reading and found that teeth from Mosasaurus possess the following traits:

  • Posterior and medial recurve 
  • Two prominent carinae bearing light serrations
  • Asymmetrical labial and lingual surfaces (lingual inflated) 
  • Labial (lip facing) surface flattened
  • Lingual (tongue facing) surface convex
  • Crown with U-shaped cross-section

 

Hmmm... That's where identification of mosasaur teeth to species becomes a bit tricky, as I've found the tertiary striae are not always as easily visible, nor always present on both sides of the tooth. In fact, I find that the partial overlaps in tooth morphology makes M. beaugei, M. hoffmanni, P. solvayi and tylosaurine teeth some of the hardest ones to keep apart. For while P. solvayi has simple striae rather than facets, as M. beaugei has, it can sometimes be hard to tell which is which. Likewise, tylosaurine teeth - T. proriger, for example (see images below for some American tylosaur teeth) - can become quite inflated and bear facets, appearing rather similar to mosasaurine teeth. The tertiary striae set them apart, of course, but can sometimes be easy to overlook as I find is especially the case with the somewhat lighter-coloured Moroccan specimens. When that happens, I find that other aspects of the tooth morphology may be enlightening, such as that Moroccan tylosaurine teeth appear to generally exhibit more lateral compression than do mosasaurine teeth from the same region. Many of these tylosaurine teeth also show their greatest curvature towards the tooth apex and maintain an upright posterior edge, their sides remaining straight for longer compared to more gradually recurved mosasaurine teeth. I further find that the posterior carina may be less well defined than in mosasaurines (images below).

 

139440976_TylosaurusprorigertoothOzanFormationNorthSulfurRiverTexas.thumb.jpg.319a6e3545104a04b97f2d5fb3344de8.jpg654153458_DamagedTylosaurusprorigertoothNorthSulfurRiver(WolfeCityFormationLimestoneCo.).thumb.jpg.f16669054216b557a5004772a02e1691.jpgTylosaurus proriger teeth from the Ozan respectively Wolfe City Formations, North Sulfur River, Texas

 

 

 

 

 

 

 

 

 

 

 

 

1067306895_TylosauruscfnepaeolicusSmokyHillChalkNiobraraFormationKansas.thumb.jpg.5ec8e3dedac4b0feb08ceef15cd9d074.jpgTylosaurus cf. nepaolicus jaw with tooth from the Smokey Hill Chalk, Niobara Formation, Kansas

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IMG_09944_resize_71.thumb.jpg.0ba02bec4f186ab2a8d317ff59e4c342.jpgIMG_09945_resize_96.thumb.jpg.2152fa03015b06603a9fd6539635a59f.jpgIMG_09946_resize_54.thumb.jpg.fc39e086c1ab80fcb4019ffcdc60324c.jpgIMG_09947_resize_97.thumb.jpg.cb86e727710ad47adf46800419de85a2.jpgIMG_09948_resize_26.thumb.jpg.285709a79c509d4a425dea8f4ad68017.jpgHainosaurus bernardi at the Museum voor Natuurkunde in Brussels

 

Hainosaurus is a tylosaurine mosasaur that may be conspecific with Tylosaurus and that, like Tylosaurus, has a knob at the end of its snout. Note, in particular, the rather straight sides of the tooth up til the strongest curvature near the tooth apex, similar to what is seem in (certain?) Moroccan specimens.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2038475936_Tylosaurinetoothcf.Hainosaurus01.thumb.jpg.129c87d357d5e55bb98c6182a0bfc4ad.jpg2132780341_Tylosaurinetoothcf.Hainosaurus02.thumb.jpg.1f768aaaf03946fef61e11255504441b.jpgTylosaurine tooth from Ouled Abdoun, Morocco

 

 

 

 

 

 

 

 

 

 

 

1057136670_Tylosaurinetoothcf.Hainosaurus03.thumb.jpg.a62a055bb51f07534280fe85ba99ae0f.jpg

 

 

 

 

 

 

 

 

 

 

 

 

 

1797763732_Tylosaurinetoothcf.Hainosaurus2_3601.thumb.jpg.b036c55b1a8350be7e33acd783dd4351.jpg1919569519_Tylosaurinetoothcf.Hainosaurus2_3602.thumb.jpg.b446cc6b27c1ff02419decb968206519.jpgTylosaurine tooth from Ouled Abdoun, Morocco

 

 

 

 

 

 

 

 

 

 

 

 

 

1088557283_Tylosaurinetoothcf.Hainosaurus2_4502.thumb.jpg.c67ba2a38998c8ee369a2f43070fa4b8.jpg294157453_Tylosaurinetoothcf.Hainosaurus2_4501.thumb.jpg.1e22a5482009c6f3f326ce322a6f1321.jpgTylosaurine tooth from Ouled Abdoun, Morocco

 

 

 

 

 

 

 

 

 

 

 

 

Similarly, I find M. beaugei and M. hoffmanni teeth to be somewhat difficult to keep apart - especially when the M. beaugei teeth get somewhat bigger and their ornamentation becomes less well-defined - as both share the typical mosasaurine flattening and prism faces labially, and bulging tooth base with facets lingually. They also both have a D- (or U-)shaped cross-section. The main difference, however, appears to be that M. hoffmanni consistently has 3, very occassionally 4, prism faces labially, has flat-bottomed facets, and that both prism faces and facets are often much less pronounced than in M. beaugei (however, see here for a M. hoffmanni tooth that is strongly facetted to the point of being visually similar to T. proriger). Below are some images of M. hoffmanni teeth from the Tylers Museum in Haarlem (older finds than the holotype) for comparison:

 

IMG_9002_resize_27.thumb.jpg.9138f153cc699085ee90dd26c7ba8df9.jpgIMG_9005_resize_97.thumb.jpg.7ee68da31ee15e9b7167ea9245d043c2.jpg

 

IMG_9006_resize_99.thumb.jpg.735fb992dd0d0e4f5d4703fd898d8432.jpgIMG_9031_resize_96.thumb.jpg.801c1e64c7867ed2cafc0039f2a8677d.jpg

 

IMG_9034_resize_57.thumb.jpg.c198db2a9ee1aecdb5dd9b7196bfa084.jpgIMG_9035_resize_74.thumb.jpg.2ec7871dbc21bf94cff9ff81d6a133ad.jpg

 

IMG_9056_resize_54.thumb.jpg.312d5ae0fc5ec326cef963e5f7920727.jpgIMG_9064_resize_53.thumb.jpg.abdb319e0f64c14f19de2691bf356be8.jpgIMG_9065_resize_70.thumb.jpg.f1d7d324348ea954cc6f69915cf3b443.jpg

 

 

All things considered, @Praefectus, I'd say that based on the photographs alone, an argument could be made both for your specimen being tylosaurine as well as mosasaurine. Notwithstanding, the lateral compression and mild posterior curvatue have me tending towards tylosaurine. My advice would be to recheck both sides of the tooth base carefully with a magnifying glass to see if you really can't discover any tertiary striae on either side of it...

'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett

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When I compare the enamel of the rooted tooth to a different tooth in my collection (which I was assuming is tylosuar), the surface is very different. The striae on the tylosaur tooth are much more pronounced and occur around the entirety of the crown. The enamel on the rooted tooth is smoother with only a hint of unevenness near the base of the lingual surface. Is that sufficient to give an identification either way?

175585928_1665964970257633_7142387121028448301_n.jpg.2a798e04d8f51e43195d7a9139a0ff87.jpg176115149_791221315100864_8113306160337079791_n.jpg.34fd344977f3c601b58fae9bdccd0e06.jpg

 

 

 

Bardet et al. 2004 differentiates Mosasaurus beaugei and Mosasaurus hoffmannii teeth based on the number of prismatic facets on the lingual and labial surface. The rooted tooth has 0 lingual facets and 3 labial facets. I was thinking this suggests an identification of Mosasaurus hoffmannii.

 

facets.JPG.17939305ba40537c64b7755218ebc4c4.JPG

 

175166214_924338698317252_5302201039002171613_n.jpg.743623b20f05426913d5c5ac1755e201.jpg176254926_741678103179524_5178367469573836842_n.jpg.e45ebcf614edbc7baeafe2023071f735.jpg1195154703_176254926_741678103179524_5178367469573836842_n-Copy.jpg.37b7de95b668e4f6b89e4427b0b1ea33.jpg

 

 

 

 

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3 hours ago, Jackson g said:

Hope you are enjoying that beauty. Didn't think I'd ever see that tooth again LOL.

 

Definitely! As mosasaur teeth go, that one's the pride of my collection! Still feel very lucky I got it. So thanks again! :tiphat:

 

Hope you don't mind me using your photograph of back then, by the way:whistle:

'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett

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On 4/20/2021 at 8:06 PM, Praefectus said:

When I compare the enamel of the rooted tooth to a different tooth in my collection (which I was assuming is tylosuar), the surface is very different. The striae on the tylosaur tooth are much more pronounced and occur around the entirety of the crown. The enamel on the rooted tooth is smoother with only a hint of unevenness near the base of the lingual surface. Is that sufficient to give an identification either way?

175585928_1665964970257633_7142387121028448301_n.jpg.2a798e04d8f51e43195d7a9139a0ff87.jpg176115149_791221315100864_8113306160337079791_n.jpg.34fd344977f3c601b58fae9bdccd0e06.jpg

 

 

 

Bardet et al. 2004 differentiates Mosasaurus beaugei and Mosasaurus hoffmannii teeth based on the number of prismatic facets on the lingual and labial surface. The rooted tooth has 0 lingual facets and 3 labial facets. I was thinking this suggests an identification of Mosasaurus hoffmannii.

 

facets.JPG.17939305ba40537c64b7755218ebc4c4.JPG

 

175166214_924338698317252_5302201039002171613_n.jpg.743623b20f05426913d5c5ac1755e201.jpg176254926_741678103179524_5178367469573836842_n.jpg.e45ebcf614edbc7baeafe2023071f735.jpg1195154703_176254926_741678103179524_5178367469573836842_n-Copy.jpg.37b7de95b668e4f6b89e4427b0b1ea33.jpg

 

Hi Trevor,


This is where, as I said, I think mosasaur tooth identification becomes tricky. Not an insignificant part of the problem arises from lack of standardization with respect to the terminology used to describe the teeth. As such, I really recommend people familiarize themselves with the work of Hornung & Reich (2015), in particular with their figure 3 (as reproduced below), which illustrates, for instance, that mosasaur teeth may have striations, prism faces or facets, but also that prism faces and facets can either occur alone or in combination.

 

urn-cambridge.org-id-binary-20170308045703739-0304-S0016774614000316-S0016774614000316_fig3g.jpeg.f1281256fef934baa4306baebb272e4e.jpeg

 

These distinctions are important, as when Bardet et al. (2004) notes that Mosasaurus hoffmanni hasn't got lingual prism faces, whereas M. beaugei does, this doesn't mean that M. hoffmanni doesn't have any lingual ornamentation by way of facets. Street and Caldwell (2017, p. 540-541), for instance, observe about the teeth of M. hoffmanni that

 

Quote

[t]he marginal teeth of [the Mosasaurus hoffmanni holotype specimen] are large, faceted and bear two carinae, which are very finely serrated [...]. They are slightly curved posteriorly and round with little to no mediolateral compression. Anteriorly, the carinae are oriented at an acute angle to each other, making the labial circumference between
the carinae considerably shorter than the lingual circumference. Therefore, in the anterior maxillary teeth the lateral face of each tooth is nearly flat between the anterior and posterior carinae. In the dentary teeth, this short, flat face is directed anterolaterally because the posterior carina is oriented along the lateral side of each tooth. The posterior carina shifts position to a more truly posterior orientation around the middle of the tooth row.

 

Importantly, they further note (ibid., p. 541) that

 

Quote

The number and size of facets formed by the enamel of the marginal teeth have been used to diagnose species of Mosasaurus since the genus was first described. [...]

In M. hoffmannii the anterior marginal teeth tend to have two or three lateral facets, two being more common on the anterior dentary teeth and three being more common on the anterior maxillary teeth of the holotype. The medial facets are more numerous and less distinct, but there are usually at least five. The number of lateral facets increases posteriorly along the tooth row as the facets get narrower, and, perhaps more importantly, the lateral surface gets larger as the posterior carina shifts posteriorly.

 

Again, there seems to be confusion here as to the meaning of the word "facet", which likewise comes to light later in the article, when the authors mention fluting as opposed for faceting. That's where my personal observations on specimens at various museums in the "Low Countries" (the Netherlands and Belgium) comes into play, for when Street and Caldwell (ibid.) mention the first "two or three facets", they are in fact referring to that number of prism faces on the buccal side of the tooth following Hornung & Reich (2015), whereas when they're talking about the "medial facets", they're actually talking about what the latter authors consider actual facetting. Even Bardet et al. (2013, p.72) seem to come back on their earlier statement of the M. hoffmanni having no lingual prisms, when they state that "[t]he high and slender shape of the crown, as well as a labial surface bearing 3 prisms and a lingual face with indistinct ones are typical characters of Mosasaurus hoffmanni (Lingham-Soliar, 1995)."

 

And while it is exactly the presence or absence of clear facetting (described as "fluting") that forms the crux of contention in the not popularly supported proposition that Mosasaurus lemonnieri (which teeth exhibit said clear facetting) may represent juvenile specimens of M. hoffmanni (source), the fact that both species occur in the same area at the same time and exhibit only minor morphological differences that may, moreover, be attributed to ontogeny makes a convincing supporting argument for observations done on M. hoffmanni. Street and Caldwell (2017, p. 553-554) have this to say about the species and its teeth:

 

Quote

M. lemonnieri is one of the better-known species of Mosasaurus with multiple specimens collected from the Campanian – lower Maastrichtian phosphate quarries of Belgium. This species agrees largely with M. hoffmannii but is generally smaller,more gracile and has higher tooth counts in all tooth-bearing elements (maxilla = 14–15, dentary = 16, pterygoid = 9–10). [...] Like M. hoffmannii, the carinae on the marginal teeth are asymmetric anteriorly in M. lemonnieri, but the labial surface is fluted instead of faceted.

 

With the above discussion on ornamentation now behind us, it might be time to briefly look back at what exactly defines a Mosasaurus tooth. Russell (1967, p. 54) states that

 

Quote

[t]he crowns of the marginal teeth in Mosasaurus are large and divided into a lingual and buccal surface by a longitudinal carina. The lingual surface of the tooth is “U”-shaped in cross-section; the buccal surface is more nearly flat, both being divided by vertical ridges into prisms. The tips of the teeth are more posterointernally inclined than the main axis of the crown.

 

To this, Bardet et al. (2013, p.71) add from personal observation that these teeth have "longitudinally structured smooth enamel". In this, Street and Caldwell (2017, p. 554) describe the main differences between M. beaugei and M. hoffmanni as follows:

 

Quote

Overall, its [Mosasaurus beaugei] morphology agrees closely with M. hoffmannii but is distinguished at the species level by the low curvature of the anterior ramus of the jugal, the lack of a posteroventral process on the jugal and the greater anterior exposure of the splenial in lateral view. Additionally, while the marginal teeth are bicarinate and the carinae are asymmetrical anteriorly, the teeth are more compressed than in M. hoffmannii.

 

The main take-away for your uncertain tooth, however, I think is that the teeth of M. hoffmanni are very robust, have prism faces on the labial side and may have more or lesser visible facets on the lingual side. In general, the teeth are rather triangular in shape with the curvature of the marginal teeth rather showing on the buccal plane rather than mesiodistally, as in tylosaurines. To show what I mean, and how robust M. hoffmanni teeth can be, here's figure 52 from Lingham-Soliar and Nolf (1989, p. 174):

 

1759788868_Mosasaurushoffmanni(IRSNBR25).thumb.jpg.c2081b908f71769be02122940327fa8e.jpg

 

 

 

 

As such, here are a couple of teeth that I believe to be Moroccan M. hoffmanni teeth:

 

2053356052_Poss.MoroccanMosasaurushoffmanniA-labial.thumb.jpg.5ac148f64b81a73f26151608f1c145b8.jpg2105223467_Poss.MoroccanMosasaurushoffmanniA-lingual.thumb.jpg.a99c2abaf423f0f3bffbb9e495ac22d5.jpgRobust tooth with 3 labial prisms and 5-6 indistinct facets. Seller stated this as M. hoffmanni, but I remain undecided as to whether this may not just be M. beaugei

 

 

 

 

 

 

 

 

 

 

 

Mosasaurus_cf._hoffmanni_01.jpg.c1047b39f494c15fe151d1dd561c2845.jpgMosasaurus_cf._hoffmanni_02.jpg.af39943ad7cf252dd8bf599a44173d72.jpgAt just over 4cm a notably smaller tooth. Three hardly noticable labial prisms, utterly indistinct prisms or facets on the lingual side.

 

 

 

 

 

 

 

 

 

 

 

Mosasaurus_cf._hoffmanni_tooth_01.jpg.0f08e33ee282ac311f5a8066c88345ea.jpgMosasaurus_cf._hoffmanni_tooth_02.jpg.5bf93bd9666b8874fe519fe0f558e589.jpgAt just under 4cm a smaller tooth still. Three hardly noticable labial prisms, almost indistinguishable prism faces lingually.

 

 

 

 

 

 

 

 

 

 

 

All of this having been said and having looked at your original post inquiring after your indeterminate tooth I'm having a hard time making my mind up about your tooth. The strongly present labial prism faces and absence of tertiary striae do not strike me as particularly tylosaurine and make me hesitate because the tooth seems so laterally compressed. As such, I'm still inclined to consider your specimen tylosaurine, but wouldn't put my hand into the flame for it. Sometimes you just need to see and hold the tooth to determine what it is, and sometimes even that may not be enough... That having been said, take a look at the below Tylosaurus proriger tooth I came across today and that, if not for the clear presence of tertiary striae, would look rather similar to your specimen in overall tooth morphology.

 

 

P.s.: As an aside, as I understand it two of the species listed in Bardet et al. (2004)'s table 2 are now considered synonymised: M. maximus => M. hoffmanni and M. conodon => M. lemonnieri (source).

'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett

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On 4/19/2021 at 9:56 PM, Praefectus said:

 

Quick correction. This tooth is not tylosaurine. It is Mosasaurus.

 

On 4/20/2021 at 5:15 AM, Praefectus said:

 

I've been reading up on mosasaurs and it seems like most (maybe all) of the species of Tylosaurus have tertiary striae along their teeth. The smooth enamel on this tooth was the first sign that my earlier identification was incorrect. 

 

I did a bit more reading and found that teeth from Mosasaurus possess the following traits:

  • Posterior and medial recurve 
  • Two prominent carinae bearing light serrations
  • Asymmetrical labial and lingual surfaces (lingual inflated) 
  • Labial (lip facing) surface flattened
  • Lingual (tongue facing) surface convex
  • Crown with U-shaped cross-section 

 

 

On 4/20/2021 at 1:06 PM, Praefectus said:

When I compare the enamel of the rooted tooth to a different tooth in my collection (which I was assuming is tylosuar), the surface is very different. The striae on the tylosaur tooth are much more pronounced and occur around the entirety of the crown. The enamel on the rooted tooth is smoother with only a hint of unevenness near the base of the lingual surface. Is that sufficient to give an identification either way?

175585928_1665964970257633_7142387121028448301_n.jpg.2a798e04d8f51e43195d7a9139a0ff87.jpg176115149_791221315100864_8113306160337079791_n.jpg.34fd344977f3c601b58fae9bdccd0e06.jpg

 

 

 

Bardet et al. 2004 differentiates Mosasaurus beaugei and Mosasaurus hoffmannii teeth based on the number of prismatic facets on the lingual and labial surface. The rooted tooth has 0 lingual facets and 3 labial facets. I was thinking this suggests an identification of Mosasaurus hoffmannii.

 

facets.JPG.17939305ba40537c64b7755218ebc4c4.JPG

 

175166214_924338698317252_5302201039002171613_n.jpg.743623b20f05426913d5c5ac1755e201.jpg176254926_741678103179524_5178367469573836842_n.jpg.e45ebcf614edbc7baeafe2023071f735.jpg1195154703_176254926_741678103179524_5178367469573836842_n-Copy.jpg.37b7de95b668e4f6b89e4427b0b1ea33.jpg

 

 

 

 

 

 

Nevermind. This tooth really is tylosaurine. I was overestimating the taxonomic power of facets for identifying mosasaur teeth. See @pachy-pleuro-whatnot-odon's post above for more detail. 

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@pachy-pleuro-whatnot-odon Thank you for the well-written response. Very enlightening to see your analysis and pictures. I now see that I was wrong. My rooted tooth and similar ones really are tylosaurine. I was looking at facets too much and not paying enough attention to general morphology. 

 

On 4/23/2021 at 7:43 PM, pachy-pleuro-whatnot-odon said:

In general, the teeth are rather triangular in shape with the curvature of the marginal teeth rather showing on the buccal plane rather than mesiodistally, as in tylosaurines.

This is a really good observation and something I completely missed. :DOH:

 

 

I'm now thinking that these two teeth are also tylosaur. 

 

668055104_20210426_012922-Copy.thumb.jpg.fc583f3ea88e99de8ba99d0d4e4d2912.jpg484200011_20210426_012932-Copy.thumb.jpg.90bf1a4081bc3bf63d4498639fc41f96.jpg

 

And that this one may be Mosasaurus hoffmannii. This tooth has buccal curvature instead of mesiodistal. 

 

1745666013_20210426_012945-Copy.thumb.jpg.f71b21639ebaa8d552891938898c2cec.jpg231702569_20210426_012952-Copy.thumb.jpg.f57da1c9450a0d86f4a80765fbec77e3.jpg

 

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On 4/26/2021 at 8:36 AM, Praefectus said:

Thank you for the well-written response. Very enlightening to see your analysis and pictures. I now see that I was wrong. My rooted tooth and similar ones really are tylosaurine. I was looking at facets too much and not paying enough attention to general morphology. 

 

On 4/24/2021 at 2:43 AM, pachy-pleuro-whatnot-odon said:

In general, the teeth are rather triangular in shape with the curvature of the marginal teeth rather showing on the buccal plane rather than mesiodistally, as in tylosaurines.

This is a really good observation and something I completely missed. :DOH:

 

No worries, I'm glad I could help :)

 

On 4/26/2021 at 8:36 AM, Praefectus said:

I'm now thinking that these two teeth are also tylosaur. 

 

668055104_20210426_012922-Copy.thumb.jpg.fc583f3ea88e99de8ba99d0d4e4d2912.jpg484200011_20210426_012932-Copy.thumb.jpg.90bf1a4081bc3bf63d4498639fc41f96.jpg

 

I'd be inclined to agree...

 

On 4/26/2021 at 8:36 AM, Praefectus said:

And that this one may be Mosasaurus hoffmannii. This tooth has buccal curvature instead of mesiodistal. 

 

1745666013_20210426_012945-Copy.thumb.jpg.f71b21639ebaa8d552891938898c2cec.jpg231702569_20210426_012952-Copy.thumb.jpg.f57da1c9450a0d86f4a80765fbec77e3.jpg

 

Certainly looks like a good candidate. I'm finding it hard to say for sure, though, as it's hard to make out the number of labial prism faces or lingual facets. The latter, however, would be an argument in favour of this tooth indeed belonging to M. hoffmanni, whereas I think the prism faces are just hard to make out due to the state of conservation of the tooth; you may instead actually be able to feel them. Also, it's hard to estimate whether the curvature is indeed buccal without seeing occlusional and basal views of the tooth, or - alternatively - a view in which at least one carina is viewed head-on. But, yes, I'd say you're right :)

'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett

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  • 3 weeks later...

Some discussion threads for those interested in Moroccan mosasaurs:

 

 

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On 3/24/2013 at 1:43 AM, jnoun11 said:

 

 

 

 

pluridens serpentis

 

SYSTEMATIC
PALAEONTOLOGY

SQUAMATA, OPPEL, 1811

MOSASAURIDAE , GERVAIS, 1853

 

HALISAURINAE
BARDET & PEREDA SUBERBIOLA ,2004

 

NEW TAXON

HALISAURUS MARSH,1869

Type species:

Pluridens walkeri , ( Lingham-Soliar , 1998 )

Maastrichtian of illulemedden bassin , NIGER

 

species:

  •  P. calabaria Longrich, 2016
  • P. serpentis Longrich, 2021
  • P. walkeri Lingham-Soliar, 1998 (type)

 

 

 

Locality:

Sidi chenane, Morocco

upper maestrichian level 3

etymology: after Cyril A. Walker to mark is contributions as a vertebrate paleontologist at the natural history museum of London ( BMNH) and is generosity to uninitiated student and to the famous alike.

 

publications

  • Konishi, Takuya; Caldwell, Michael W.; Nishimura, Tomohiro; Sakurai, Kazuhiko; Tanoue, Kyo (2015). "A new halisaurine mosasaur (Squamata: Halisaurinae) from Japan: the first record in the western Pacific realm and the first documented insights into binocular vision in mosasaurs". Journal of Systematic Palaeontology: 1–31. doi:10.1080/14772019.2015.1113447.
  • T. Lingham-Soliar. 1998. A new mosasaur Pluridens walkeri from the Upper Cretaceous, Maastrichtian of the Iullemmeden Basin, southwest Niger. Journal of Vertebrate Paleontology 18(4):709-707.
  • Nicholas R. Longrich (2016). "A new species of Pluridens (Mosasauridae: Halisaurinae) from the upper Campanian of Southern Nigeria". Cretaceous Research. in press. doi:10.1016/j.cretres.2016.03.013.
  • Lindgren J, Siverson M. 2005. Halisaurus sternbergii, a small mosasaur with an intercontinental distribution. Journal of Paleontology 79 (4): 763–773.
  • Michael J. Polcyn, Johan Lindgren, Nathalie Bardet, Dirk Cornelissen, Louis Verding, and Anne S. Schulp (2012) Description of new specimens of Halisaurus arambourgi Bardet & Pereda Suberbiola, 2005 and the relationships of Halisaurinae. Bulletin de la Société Géologique de France 183:123-136 doi:10.2113/gssgfbull.183.2.123 http://bsgf.geoscienceworld.org/content/183/2/123.abstract

 

Holmes, Robert B.; Sues, Hans-Dieter (2000). "A partial skeleton of the basal mosasaur Halisaurus platyspondylus from the Severn Formation (Upper Cretaceous: Maastrichtian) of Maryland" (PDF). Journal of Paleontology 74 (2): 309–16.
 
University of Cincinnati (8 December 2015). "Unique Mosasaur fossil discovered in Japan". ScienceDaily. Retrieved 12 December 2015

Pluridens serpentis, a new mosasaurid (Mosasauridae: Halisaurinae) from the Maastrichtian of Morocco and implications for mosasaur diversity(2021):  https://www.sciencedirect.com/science/article/abs/pii/S0195667121001294 Nicholas R.Longrich, NathalieBardet, fatimaKhaldoune, Oussama KhadiriYazami, Nour-EddineJalil

 

diagnosis : moderatly large mosasaur. very long.slender dentary,anterior half cross section almost circular extending to tip. 28 -plus teeth
in dentary,close set. tooth crown short.the teeth looking like Halisaurus Arambourgi but bigger and serrated on cutting edge. 21-22 teeth on a maxillary 28 teeth on a dentary,10 teeth on pterygoid. . It is referred to Pluridens based on the elongate and robust jaws, small teeth, and specialized tooth implantation. Pluridens is referred to Halisaurinae based on the posteriorly expanded premaxilla, long premaxilla-maxilla suture, broad premaxillary facet on the maxilla, closed otic notch, and small, striated, hooked teeth. The orbits are reduced relative to other halisaurines while the snout is robust and flat with a broad, rounded tip. The jaws bear numerous small, hooked, snake-like teeth.

this very rare mosasaur is now described in a moroccan phosphates all the skull mesured the same size : 32 inches .

 

post-2284-0-95749100-1364042311_thumb.jpg

skull from top

 

post-2284-0-85987400-1364042613_thumb.jpg

same skull from right

 

post-2284-0-63343200-1401965501_thumb.jpg

 

comparaison between jugal of halisaurus arambourgi ( top), and pluridens serpentis (bottom)

the jugal of pluridens serpentis is very similar than platecarpus ptychodon

20190119_142207.jpg

tooth of pluridens serpentis ,you can see the serration on cutting edge

59022791_10216082899638716_597148239673688064_n.jpg

20210513_141813.jpg

20210513_141942.jpg

For those of you who have access to Research Gate the full text of the paper is now available here: https://www.researchgate.net/publication/351418084_Pluridens_serpentis_a_new_mosasaurid_Mosasauridae_Halisaurinae_from_the_Maastrichtian_of_Morocco_and_implications_for_mosasaur_diversity

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Thought I would add my Moroccan Tylosaur tooth to this thread. I have yet to determine what the skull material is. 57mm image.thumb.jpg.23b434d2f7bb5e6ced29de61c0ba038c.jpgimage.thumb.jpg.ca373ffe52939b74354b3f9cb6861367.jpg

Edited by DenverEdge
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  • 2 months later...

To keep this thread up-to-date, @Praefectus and I just published an article on the occurrence of Mosasaurus hoffmannii in Morocco. Read more about it in the below thread:

 

 

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'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett

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Xenodens calminechari

gen. et sp. nov.

 

Reptilia Laurenti 1768

 

Squamata Oppel 1811

 

Mosasauridae Gervais 1853

 

sub family: mosasaurinae

 

tribe: mosasaurini

 

specie: Xenodens calminechari

 

Xenodens ("strange tooth") is an extinct genus of marine lizard belonging to the mosasaur family. It currently contains a single species, X. calminechari (From Arabic کالمنشار, meaning "like a saw"), which is known from Late Maastrichtian phosphate deposits in the Ouled Abdoun Basin, Morocco. Its closest known relative is believed to be the durophagous Carinodens.

Estimated to have measured around 1.6 meters (5.2 ft) in length, both the genus and type species are named for the mosasaur's short and flattened blade-like teeth that collectively form a set of saw-like jaws. This is a feature that has never been seen in any other tetrapod but converge with the jaws of modern dogfish sharks and piranhas. Based on the feeding behavior of these animals, paleontologists believe that Xenodens used its highly specialized dentition for a broad diet on cephalopods, crustaceans, fish, and scavenged marine reptiles.

the posterior teeth of the maxillary look the same has the posterior teeth of carinodens. (Fossils of the Harrana Fauna and the Adjacent Areas  from Hani F Kaddumi) P 52 fig:28

 

dentary with 15 teeth showing an heterodontia . lenght of the dentary 215 mm

maxillary showing 14 teeth. lenght of maxillary: 21 cm

pterygoid: 24 teeth. lenght of pterygoid: 21cm

 

publication: https://www.researchgate.net/publication/348567291_Xenodens_calminechari_gen_et_sp_nov_a_bizarre_mosasaurid_Mosasauridae_Squamata_with_shark-like_cutting_teeth_from_the_upper_Maastrichtian_of_Morocco_North_Africa

references: Longrich, N.R.; Bardet, N.; Schulp, A. S.; Jalil, N (2021). "Xenodens calminechari gen. et sp. nov., a bizarre mosasaurid (Mosasauridae, Squamata) with shark-like cutting teeth from the upper Maastrichtian of Morocco, North Africa". Cretaceous Research. doi:10.1016/j.cretres.2021.104764.

 

1.jpg

 

 

3.jpg

pterygoid

2.thumb.jpg.bcff4b6bc6ed1fe7fed53a7537d2e7b4.jpg

right dentary

 

20220128_112857732.thumb.jpg.6f93d5460f7b75e560dbded576119eb0.jpg

right maxillary and left dentary

 

dentaire1.jpg

20220128_112916358.jpg

dentaire2.jpg

maxillaire1.jpg

pterygoide24.jpg

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The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it. Terry Pratchett ...

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5 hours ago, jnoun11 said:

1.jpg3.jpg2.thumb.jpg.bcff4b6bc6ed1fe7fed53a7537d2e7b4.jpg

 

20220128_112857732.thumb.jpg.6f93d5460f7b75e560dbded576119eb0.jpg

 

Awesome! Does this mean more material has now been found of this species? Is it known which layers and deposits the material derives from?

'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett

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