The latest friendly titanosaur to come along hails from Morocco, making it the first named Moroccan titanosaur but not the first record. Other occurrences are mentioned here. For some reason it seems like the new names are always specimens that weren't included. Still lots of titanosaurs out there!
Genus and Species: Phosphatotitan khouribgaensis. The genus name combines a reference to the phosphates of Morocco with the common titanosaur suffix "-titan", and the species name refers to Khouribga Province (Longrich et al. 2026). This produces something like "phosphate titan from Khouribga".
Citation: Longrich, N. R., A. Pérez-Moreno, V. Díez Díaz, X. Pereda-Suberbiola, N. Bardet, and N.-E. Jalil. 2026. A titanosaurian sauropod with South American affinities (Lognkosauria: Argentinosauridae) from the Late Maastrichtian of Morocco and evidence for dinosaur endemism in Africa. Diversity 18(5): 241. doi: doi.org/10.3390/d18050241.
Geography and Stratigraphy: The type and only known specimen came from Sidi Chennane in the Oulad Abdoun Basin, Khouribga Province, Béni Mellal-Khénifra Region, north-central Morocco. Stratigraphically it is from the lower part of Couche III, thought to date to the late Maastrichtian of the Late Cretaceous (Longrich et al. 2026). Couche III is better known for marine fossils, but there is a small but growing dinosaurian assemblage. None of the dinosaurian taxa is known from particular complete material (spoiler), and apart from P. khouribgaensis, all come from Upper Couche III (Longrich et al. 2026). ("Couche", incidentally, is French for "bed"; I found that oddly satisfying to learn after having typed "Couche III" numerous times for various marine reptiles and pterosaurs in The Compact Thescelosaurus.)
Holotype: MHNM.KHG.888 (Muséum d'Historie naturelle de Marrakech, Marrakech, Morocco), an associated specimen including a posterior dorsal vertebra, partial sacrum, a (first?) caudal, and parts of the ilia, ischia?, and pubic bones (Longrich et al. 2026). They belonged to an animal thought to have been on the order of 4 metric tons (about 4.4 US tons) and perhaps 10 to 12 m long (33 to 39 ft) (Longrich et al. 2026).
|
| The various parts of the Phosphatotitan holotype (Figure 3 in Longrich et al. 2026). A. dorsal vertebra. B. caudal vertebra. C. pelvic bones and sacrum. D. anterior iliac blade. E. posterior iliac blade. CC-BY-4.0. |
This is admittedly not the most promising type specimen I've ever seen. The pelvic pieces in particular look like they never saw it coming. ("It" is left to your imagination.) Despite this, some interesting features are evident. The centra of both the dorsal vert and caudal vert are proportionally quite short, and the neural arches are also rather compressed fore-aft, even accounting for crushing. These are lognkosaurian features. The dorsal vert seems to have featured wide wing-like processes, but the exact shape and extent are unclear due to incomplete preservation. The centrum of the caudal vert is wider than tall, and the neural arch is broad and compressed fore-aft, with an anterior curve at the tip of the neural spine. Most of the sacral verts are not simply well-fused but have formed a rod-like feature with the individual vertebrae almost indistinguishable. The pelvis, such as can be interpreted, has short broad pubic bones with large boots. The probable ischium is L-shaped with a "long, narrow distal blade" (Longrich et al. 2026).
As noted in the "Coming Attractions" post linked above, there is also a titanosaur known from the Couche III phosphates of Sidi Daoui, represented by hindlimb material. Longrich et al. also discuss this one briefly. Unlike P. khouribgaensis, the Sidi Daoui form is from Upper Couche III, making it more recent by perhaps a million or so years. The authors regard it as unlikely to be the same as P. khouribgaensis on these stratigraphic grounds, although the two are placed as sister taxa in their new Argentinosauridae, and I've gone on record with my reservations on straight-up stratigraphic/geochronologic differentiation of species. (On the other hand, with such scrappy material, did the authors' biogeographic character exert undue attraction?) More complete material is needed to resolve this.
Interestingly, several of the odd features of P. khouribgaensis are seen to a lesser extent in Patagotitan mayorum and, more distantly, Argentinosaurus huinculensis (Longrich et al. 2026). This gets us to a notable case of "one of these things is not like the others", as two of those are super-titanosaurs that lived about 100 million years ago in what is now Argentina and the other is a much more modestly sized form that lived about 68 million years ago in what is now Morocco. Neither P. khouribgaensis nor the Sidi Daoui form were found to be particularly close to any of the more obvious suspects, e.g., titanosaurs of similar age from northern Africa or Iberia. Many of them do share a similar size class, though, despite different evolutionary relationships. The authors suggest two basic mechanisms for this: the classic "restricted geography", or broader evolutionary trends favoring titanosaurs of smaller body size (Longrich et al. 2026).
References
Longrich, N. R., A. Pérez-Moreno, V. Díez Díaz, X. Pereda-Suberbiola, N. Bardet, and N.-E. Jalil. 2026. A titanosaurian sauropod with South American affinities (Lognkosauria: Argentinosauridae) from the Late Maastrichtian of Morocco and evidence for dinosaur endemism in Africa. Diversity 18(5): 241. doi: doi.org/10.3390/d18050241.
No comments:
Post a Comment