Spinosaurus's relatives... Or Just other Spinosaurids: Breaking down the family tree

The Family Tree Of Spinosauridae. The creatures which have a red line over their names are the ones we've already covered

Ah, the spinosauridae, a fascinating group of creatures from all aspects. If you haven't gotten it already, we are back at it boys! Today we are going to break down the spinosauridae family tree, and then we are going to explain every clade, every anatomical similarities and differences between genuses, species or genders. So without further to say, let's get straight into it.

1.Spinosaurinae

1.Spinosaurini

Spinosaurini is all about Spinosaurus and its dubious counterparts. For example, in the family tree all we see of spinosaurini is the holotype of S.aegyptiacus, FSAC-KK 11888, MSNM V4047, "Spinosaurus B" and Sigilmassasaurus. Well, all of these are specimens, except Sigilmassasaurus which is a dubius spinosaurid. But why are they seperated? Well, looking at what is found of each may help.

• S.aegyptiacus Holotype: Dentary Bone, Neck Vertebra, Teeth, few spine bones
• FSAC-KK 118888: Lacrimal, Squamosal,Angular and Frontal Bones, Tail vertebra, Pelvis, Legs and Feet, Ribs, Spine , A partial neck vertebra and a phalange (finger bone)
• MSNM V4047: Maxilla, PMX, Nasal and Jugal Bone
• Spinosaurus B: Tail Vertebra, Pelvic fragments, ribs, Spine Bones, Leg bones
• Sigilmassasaurus: Neck Vertebra

As you can see, the most of the specimens only have skull material in them. Sadly there is not much to compare. And what there is to compare is too little for us to tell a creature from another. For example, If we didn't find Ichthyovenator's spine bones, we would possibly think it is a spinosaurus. So, I won't do much with spinosaurini. Let's continue.

2.Irritator

I.challengeri's holotype

Irritator is an South American Spinosaurid which is only known from skull material, specifically, the frontal, fragments of the maxilla, the jugal, the nasal, the lacrimal, the squamosal, the quadratojugal, the angular and the surangular, and fragments of the dentary. There is also proof that it possibly fed on pterosaurs, and that because a pterosaur neck vertebra from South America has been found having a spinosaurid tooth similar to that of Irritator.

3.Ichthyovenator and Camarillasaurus

Fossils of Camarillasaurus and Ichthyovenator

Ichthyovenator is only known from some spine bones and its illium, so the only thing that's sure about it is a break in its back hump. Camarillasaurus is only known from some vertebrae. Again, as we saw in spinosaurini, not much material to compare. In fact, Camarillasaurus was once thought to be a ceratosaur.

2.Baryonichinae

Baryonichinae is a family of spinosaurids which includes baryonyx and its relatives. I would cover each one seperately, even though we are going to focus one thing: their crests. Each baryonichid has a similar crest, if it has one. Morphologically, they look very much like each other, just with different crests and sizes. So, baryonichidae is off the list... or is it? So in earlier posts we talked about the baryonyx in Australia, but looking at baryonichidae's fossil record, most fossils seem to be in Africa-Europe. No South American fossils. So how did baryonyx get there? Was this all a hoax? I think that this should be left for another post. For now, it's just a mystery.

3.Vallibonavenatrix

So Vallibonavenatrix is just an unclassified genus of spinosaurid from spain known from some ribs, some vertebrae and the illium. So, it's just another one of those poorly preserved spinosaurids. Not much else to say.

And that was how today's post ends. Thank you so much for reading this far and for supporting this series! See you!