Valentine’s day (one day early)
February 13, 2021
Fiona made me a cake for tomorrow.
She asked me if the flowers were OK. I said there were flowering plants at the end of the Cretaceous, so this is acceptable so long as we interpret the sauropod as a titanosaur.
February 22, 2021 at 2:24 am
Since we now know that angiosperms date well back to the Jurassic period, we can adorn (many of) our sauropods with as many flowers as we like.
We already knew there were bees, then, so we *probably* should have suspected there were flowers, too, but there’s nothing like a blossom trapped in amber to plug the gobs of nay-sayers.
We may now wonder why the angiosperms had to wait for K-T before they, as it were, blossomed forth. Fiona may have hit upon the explanation: Sauropods preferred to drowse in and on flowerbeds, so the flowers were kept down until the sauropods were finally and suddenly obliged to give up the habit, the habitat, and the ghost.
February 22, 2021 at 5:46 am
We may now wonder why the angiosperms had to wait for K-T before they, as it were, blossomed forth.
I know you’re setting up a joke, and I’m not trying to be a joyless clod. But angiosperms didn’t wait for the K-T. At least in North America, the diversity and abundance of angiosperm pollen increases almost linearly from 125Ma to 65Ma, and from 90Ma on, some floras are 80% angiosperm, although the average is only 40% angios through the Late Cretaceous. According to the pollen record, there are no sudden jumps, no revolutions, no big extinction/replacement events, just the slow and steady spread of angiosperms over about 60 million years. This is all from Lupia et al. (1999). I’ve been meaning to blog about this for ages, you just gave me an opening!
Lupia, R., Lidgard, S. and Crane, P.R., 1999. Comparing palynological abundance and diversity: implications for biotic replacement during the Cretaceous angiosperm radiation. Paleobiology, pp.305-340.
February 22, 2021 at 10:48 am
Hang on, though — given that we had angiosperms from the late Jurassic, and that they were increasing in prevalence through the Cretaceous, does it follow that we had flowers?
February 22, 2021 at 11:20 am
Briefly: yes. The earliest fossil angiosperms are recognized by their flowers, not vice versa, and monocots and eudicots had diverged by the Aptian-Albian (Sauroposeidon time!).
Sauquet et al. (2017):
“The oldest confirmed fossil flowers are no older than 130 Ma, whereas estimates for the most recent common ancestor of all living angiosperms (that is, the age of our reconstructed ancestral flower) range between 140 and 250 Ma. By the time of the first extensive record of fossil flowers in the late Aptian and Albian (100–120 Ma), fossils indicate that the radiation of angiosperms had proceeded well into Nymphaeales, Magnoliidae, Chloranthaceae, early-diverging eudicots and early-diverging monocots.”
Sauquet, H., von Balthazar, M., Magallón, S., Doyle, J.A., Endress, P.K., Bailes, E.J., de Morais, E.B., Bull-Hereñu, K., Carrive, L., Chartier, M. and Chomicki, G., 2017. The ancestral flower of angiosperms and its early diversification. Nature Communications, 8(1), pp.1-10.
February 22, 2021 at 11:29 am
Wow. Things move fast.
Next thing, you’ll be telling me that volcanoes weren’t constantly erupting in the background of every dinosaur scene throughout the Mesozoic.
February 22, 2021 at 12:19 pm
If I learned one thing from the dinosaur books of my childhood, it’s that volcanoes didn’t evolve the ability to not erupt until roughly the start of the Ice Age.
March 17, 2021 at 6:43 am
What I am hearing is that it was the mid-late Jurassic sauropods keeping the angiosperms down.
March 17, 2021 at 4:48 pm
Warning–I’m going to poindexter your joke again.
Interestingly (to me, anyway), it doesn’t seem like anything was keeping the angiosperms down. I don’t know if they actually originated in Asia or if that’s just where we have the earliest fossils from, but once they got into North America the diversity and abundance increase almost linearly through the Cretaceous. No big jumps, no plateaus, just a steady, inexorable spread over a span of time as long as the whole Cenozoic.
I think that’s why it’s been a challenge to convincingly tie angiosperm diversification to dinosaur evolution or vice versa: angiosperms show the same increases before and after derived ceratopsians and hadrosaurs arrived in North America, and no dinosaur clade or even guild tracks the angiosperm diversification very closely or for very long. I mean, obviously angiosperms and dinos did interact, since angiosperms were doing that steady spread through dinosaur-dominated ecosystems, but they spread just as well through tenontosaur-, nodosaur-, and sauropod-dominated ecosystems of the Early Cretaceous, and hadrosaur-, ceratopsian-, and ankylosaur-dominated ecosystems of the Late Cretaceous.
I think the “no jumps” pattern in either diversity or abundance is weird; 60 million years is a very gradual pace for a sustained takeover.
March 17, 2021 at 5:15 pm
Sorry, didn’t most late-Jurassic sauropods flub the J-K transition?
March 17, 2021 at 8:18 pm
They did, in that after the gap in the earliest Cretaceous in North America for which we have no rocks, the Early Cretaceous sauropods are generally from different clades than the Late Jurassic ones: turiasaurs (Moabosaurus and Mierasaurus) and basal somphospondyls (Paluxysaurus and Sauroposeidon) show up, and there’s nary a diplodocoid, camarasaur, or haplocanthosaur to be found. Brachiosaurids and other basal titanosauriforms do much better in the Early Cretaceous, with Abydosaurus, Cedarosaurus, Sonorasaurus, and Venenosaurus after the gap (plus Astrodon and Brontomerus somewhere in the tree), compared to lonely Brachiosaurus altithorax in the Morrison. In contrast to the Morrison, sauropods were usually the rarest large animals in Early Cretaceous faunas in North America, but they were still pretty diverse, as we discussed in our Brontomerus paper back when.
Also, the whole “sauropods tanked in the Cretaceous” thing has always been a specifically North American pattern–titanosaurs and rebbachisaurids flourished throughout the Cretaceous on other continents, and hadrosaurs and ceratopsians were less dominant even when they were around. Steve Brusatte covers this very well in his book The Rise and Fall of the Dinosaurs, which I should review here sometime.