rekordy: Jellyfish

Evidence: 100 • authority: 72

Jellyfish, also known as sea jellies or simply jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals, although a few are anchored to the seabed by stalks rather than being motile. They are made of an umbrella-shaped main body made of mesoglea, known as the bell, and a collection of trailing tentacles on the underside. Via pulsating contractions, the bell can provide propulsion for locomotion through open water. The tentacles are armed with stinging cells and may be used to capture prey or to defend against predators. Jellyfish have a complex life cycle, and the m…

Evidence: 34 • authority: 80

Oldest known animal sex chromosome evolved in octopuses 380 million years ago

Evidence: 34 • authority: 80

The oldest fish in the world lived 500 million years ago

Evidence: 29 • authority: 72

The Ediacaran biota ( EE-dee-ACK-ər-ən; formerly Vendian) is a group of large, biologically complex, mostly soft-bodied organisms, which lived during the Ediacaran Period (c. 635–538.8 Mya). These were unusual tube and frond-shaped, mostly sessile, organisms. Three distinct assemblages of these organisms have been discovered, preserved as trace fossils in Ediacaran sandstone. They represent the earliest known complex multicellular organisms. The Ediacaran biota may have undergone evolutionary radiation in a proposed event called the Avalon explosion, 575 million years ago. This was after the Earth had thawed from the Cryogenian period's extensive glaciation. This biota largely disappeared w…

Evidence: 25 • authority: 72

The Cambrian explosion (also known as the Cambrian radiation or Cambrian diversification) is an interval of time beginning approximately 538.8 million years ago in the Cambrian period of the early Paleozoic, during which a sudden radiation of complex life occurred. The fossil record of this period contains the first appearances of practically every animal phyla, implying that nearly all animal life has its origin during this radiation. It lasted between 13 and 25 million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification in other groups of organisms as well. Before early Cambrian diversification, most organisms were relativ…

Evidence: 25 • authority: 80

55 million years: Australia’s oldest crocodile eggshells found in Queensland

Evidence: 25 • authority: 80

Oldest Mars meteorite loses 400 million years

Evidence: 25 • authority: 72

The Cambrian ( KAM-bree-ən, KAYM-) is the first geological period of the Paleozoic Era and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran Period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma. Most of the continents were located in the southern hemisphere surrounded by the vast Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new convergent plate boundaries and continental-margin arc magmatism along its margins that helped drive up global temperatures. Laurentia lay across the equator, separated from Gondwana by the opening Iapetus Ocean. The C…

Evidence: 21 • authority: 92

Population genomics of a sailing siphonophore reveals genetic structure in the open ocean.. The open ocean is a vast, highly connected environment, and the organisms found there have been hypothesized to represent massive, well-mixed populations. Of these, the man-o'-war or bluebottle (Physalia) is uniquely suited to long-distance travel, using its gas-filled float and muscular crest to catch the wind and sail the sea surface. We tested the hypothesis of a global, panmictic Physalia population by sequencing whole genomes of 151 samples and found five distinct lineages, with multiple lines of evidence indicating strong reproductive isolation, despite range overlap. We then scored thousands o…

Evidence: 21 • authority: 80

Comb jellies, not sponges, might be the oldest animal group

Evidence: 21 • authority: 72

Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'). They are filter feeders that are typically bound to the seabed, being sessile. Sponges are one of the most ancient members of living seabed community (macrobenthos), with many species being important reef-builders. Some sponge species inhabit freshwater. Sponges are multicellular organisms consisting of jelly-like mesohyl sandwiched between two thin layers of cells, and usually have tube-like bodies full of pores and channels that allow water to circulate through them. They have unspecialized cells that can transform into other types and that often migrate between the main cell…

Evidence: 21 • authority: 72

The largest extant animal, as well as the largest animal to ever exist, is the blue whale. The maximum recorded weight was 190 tonnes for a specimen measuring 27.6 metres (91 ft), whereas longer ones, up to 33.6 metres (110 ft), have been recorded but not weighed. It is estimated that this individual could have a mass of 250 tonnes or more. The longest non-colonial animal is the lion's mane jellyfish (120 ft, 36.6 m). While controversial, estimates for the weight of the sauropod Bruhathkayosaurus suggest it was around 110–170 tons, with the highest estimate being 240 tons, if scaled with Patagotitan, although actual fossil remains no longer exist, and that estimation is based on described d…