It May Be Soon Possible To Determine The Sex Of Dinosaurs From Hormones In Fossil Bones

[Prehistory Resurrection]

Link to article; https://gizmodo.com/sexing-dinos-paleontologists-seek-fossilized-hormones-1851124708

[Faelrin]

Sounds interesting but I wonder how they could account for those possibly with abnormally high levels of a particular hormone in a particular sex that typically doesn't? Like for example there's some reports of female lions with high testosterone levels causing them to develop male like features (similar to people with PCOS for example). I imagine they would need a relatively large sample size to account for such, which isn't exactly easy with fossil animals that typically have few specimens (though there are exceptions).

[DefinitelyNOTDilo]

Definitely wouldn't be feasible for all species, but for something super well known it would be super nice! I wonder if this may show some correlation between Tyrannosaurus gracility and gender.

[shahinos]

Sounds interesting but I wonder how they could account for those possibly with abnormally high levels of a particular hormone in a particular sex that typically doesn't? Like for example there's some reports of female lions with high testosterone levels causing them to develop male like features (similar to people with PCOS for example). I imagine they would need a relatively large sample size to account for such, which isn't exactly easy with fossil animals that typically have few specimens (though there are exceptions).

As long as there aren't any other ways of identifying sex they won't be able to definitively assign a sex, I guess. However, and I'm definitely no expert, a quick google search tells me that examples like this are quite rare. I read of eight lionesses out of a female global population of around 10-12 000, three of which were in captivity. So I guess that any hormones found in fossils would lead to a conclusion/assumption that the examined individual belongs to the corresponding sex.

[Papi-Anon]

Another rare anomaly to consider would be specimens who in life might have had some variation of intersex characteristics due to being chimeras (as in fused fraternal twin embryos, and in this case fraternal twins of opposite sexes). Though, I have no idea what the rate of such abnormalities are in extant archosaurs, especially since crocodylians' male/female determination is due to temperature ranges during incubation. Has it been confirmed if avian sex-chromosome genetics evolved during/prior to the estimated appearance of early bird-like dinosaurs using the molecular clock? I know they did this to determine that the eutherian XY/XX chromosome system evolved some time during the Jurassic which is around the time metatherian-like fossils pop up.

[Faelrin]

@Papi-Anon I can't really help with your questions, but what you mentioned kind of reminds me that gynandromorphs are a thing in extant birds, where one side expresses male characteristics, and the other side expresses female characteristics. It would be really interesting if something like that was found with a non-avian dinosaur, but again I imagine the material would need to be pretty good to work from in that case (like from an articulated specimen perhaps).

[Over9K]

I imagine they would need a relatively large sample size to account for such, which isn't exactly easy with fossil animals that typically have few specimens (though there are exceptions).

Sounds like a job for T.rex. Larger sample size, the paper becomes a global headline ("IT'S A BOY! T.rex gender revealed!"), and it might settle the "Robust/Gracile" debate.