Middle-Late Triassic insect radiation revealed by diverse fossils and isotopic ages from China
Daran Zheng1,2, Su-Chin Chang2,*, He Wang1, Yan Fang1, Jun Wang2, Chongqing Feng2, Guwei Xie3,4, Edmund A. Jarzembowski1,5, Haichun Zhang1 and Bo Wang1,6,*
Science Advances 05 Sep 2018: Vol. 4, no. 9, eaat1380
Fig. 3 Representative fossils from Tongchuan and Karamay entomofaunas.
Tongchuan entomofauna (A to C, E to J, and L to O), and Karamay entomofauna (D and K). (A) Zygophlebia (Odonatoptera: Zygophlebiidae), NIGP163160; (B) Locustavidae (Orthoptera), NIGP162042; (C) Prochoristella (Mecoptera: Permochoristidae), NIGP162043; (D) Corixidae, NIGP162044; (E) Boreocixius (Hemiptera: Surijokocixiidae), NIGP162045; (F) Dunstaniidae (Hemiptera), NIGP162046; (G) Aphidoidea (Hemiptera), NIGP162047; (H) Chauliodites (Grylloblattida: Chaulioditidae), NIGP162048; (I) Cicadocorinae (Hemiptera: Progonocimicidae), NIGP162049; (J) Ichnogenus Folindusia (Trichoptera), NIGP162050; (K) Ichnogenus Terrindusia (Trichoptera), NIGP162051; (L) Myxophaga (Coleoptera), NIGP162052; (M) Elateriformia (Coleoptera), NIGP162053; (N) Dytiscoidea (Coleoptera), NIGP162054; (O) Cicadocorinae (Hemiptera: Progonocimicidae), NIGP162055. Scale bars, 5 mm (white), and 1 mm (black).
Abstract
The Triassic represented an important period that witnessed the diversification of marine and terrestrial ecosystems. The radiations of terrestrial plants and vertebrates during this period have been widely investigated; however, the Triassic history of insects, the most diverse group of organisms on Earth, remains enigmatic because of the rarity of Early-Middle Triassic fossils. We report new insect fossils from a Ladinian deposit (Tongchuan entomofauna) dated to approximately 238 to 237 million years ago and a Carnian deposit (Karamay entomofauna) in northwestern China, including the earliest definite caddisfly cases (Trichoptera), water boatmen (Hemiptera), diverse polyphagan beetles (Coleoptera), and scorpionflies (Mecoptera). The Tongchuan entomofauna is near the Ladinian-Carnian boundary in age, providing a calibration date for correlation to contemporaneous biotas. Our findings confirm that the clade Holometabola, comprising most of the modern-day insect species, experienced extraordinary diversification in the Middle-Late Triassic. Moreover, our results suggest that the diversification of aquatic insects (a key event of the “Mesozoic Lacustrine Revolution”) had already begun by the Middle Triassic, providing new insights into the early evolution of freshwater ecosystems.
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See Elizabeth Pennisi's article:
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Os autores escreveram:
“Our findings confirm that the clade Holometabola, comprising most of the modern-day insect species, experienced extraordinary diversification in the Middle-Late Triassic.” ... “In summary, our findings confirm that holometabolous and aquatic insects experienced a radiation event in the Middle Triassic.”
Por que isso é importante: Porque é significativamente mais cedo do que o esperado - parcialmente baseado na evidência de fósseis, mas também em datas previamente propostas de pesquisas moleculares.
No artigo da Pennisi:
“The sites underscore that this burst of evolution took place much earlier than researchers had thought, particularly for water-loving insects.” ... “This earlier date for the expansion of insect diversity aligns it with the explosion in plant diversity happening at that time.”
Convém destacar que essas descobertas não são incomuns – é mais um padrão característico descoberto pelos paleontólogos - surgimento abrupto e estase.
Eita seleção natural preguiçosa - 237 milhões e tudo permanece como antes no quartel de Abrantes, oops de Darwin!
