Отправлено: 21.07.23 21:28. Заголовок: Naturalized species of the world
Since we had been talking about it these past days, I thought that we could have a topic only to talk about naturalized species that could leave descendants in the Neocene. I'll start by asking who could be the descendant of tall (megalocerus-sized) deer for the temperate forests of Southern South America, the red deer or the fallow deer? Both are introduced in Argentina and Chile. Regarding competition with deermaras and local deers, its height will allow them to eat leaves from tall branches.
Ok! I think that, while they spend most of their lives in freshwater, they would still be able to move in estuarine regions. Also, I finished the description of the blackbuck's descendant:
Yamanduntherium, the Beast of Yamandú (Yamaduntherium giraffoides) Order: Artiodactyla Family:Bovidae Habitat:Savannas and open woodlands of Central and Southern South America Among the damages caused by humans in nature, the introduction exotic species was probably one of the most disruptive. Several native animals and plants were outcompeted by the newcomers, disappearing completely from the face of Earth. With the arrival of the Neocene, the descendants of these exotic species had become part of the environment , completely integrated in the trophic relations. One of such cases is the yamandutherium, a descendant of the blackbuck (Antilope cervicapra) that was introduced in Argentina. An inhabitant of savannas and open woodlands of Central and Southern South America, the animal name means “the Beast of Yamandú” (Yamandú was one of the names of the supreme god of the tupi-guarani mythology). The yamanduntherium is a large animal that evolved as an analogue to giraffes in South America. A fully grown specimen stands 450 to 600 cm and 250 cm to 350 cm at the shoulder, with males being far taller than the females. The largest female has a maximum height of 500 cm. Weighing close to 1,300 kg, males are also heavier than females. Much of their size comes from their long legs and neck, which can reach 250 cm. Different from giraffes, their body isn’t short, measuring 500 cm. Being more elongated, it gives a more “proportional” appearance to the animal. Also different from the Nanditherium of the Hindustan, the yamanduntherium is an elegant and agile animal, being able to run 70 km/h. The males have a two-tone colouration, with the upper parts and outsides of the legs being cinnamon brown, the underparts and the insides of the legs are all white. The head is darker, which contrasts with the white fur on the chin and around the eyes. The females and juveniles are yellowish-brown in the upper parts and become more yellowish-fawn in the belly and legs. The horns are only present in the males. They are short, being 60 cm long and straight with tips that are hooked. The tail is short. This species survives primarily on a diet of leaves from several species of trees that are found in its habitats. They are able to pick food from tall trees, avoiding competition with smaller herbivores. Their long tongue is used to grasp branches and bring it to the month. Yamanduntherium will also eat fruits and seed pods. Due to their size, an adult yamanduntherium have no predators. The newborns can be killed by large carnivores, but females will defend their offspring fiercely with kicks and stomps. Females live in herds of 8 to 15 close related individuals. These groups are led by a matriarch and the other members are her sisters, daughters and their offspring. Adult males are solitary, but young individuals can form small groups of 5 individuals. The mating season happens during the end of winter and early spring. The males will establish a territory under the basis of the local distribution of female groups. While tolerant with each other during most of the year, the males become aggressive during the mating season. They actively defend resources in their territories, nearly 1.2 to 12 hectares in size. These areas are marked with scent using preorbital gland and interdigital gland secretions, feces and urine. While other males are not allowed into these territories, females are allowed to visit these places to forage. Rival males that invade these territories will be received with aggressive displays, such as kicks and loud grunts. However, direct disputes are rare. The males will stand in parallel, measuring each other. If they have similar sizes, they’ll bump against each other. Occasionally, bites can be given by the combatants in each other's necks. Due to their long necks, they can't use the horns in these disputes. Yamanduntherium can’t use the neck like how male giraffe’s used in intraspecific fights. This way, the horn is only a vestige of their ancestral lineage. The gestation period of yamandutherium is on average 445-457 days, producing one offspring. Before the birth, the female will leave the herd. She will give birth alone and standing up, and the offspring will stand up anywhere between 5-20 minutes post-birth. Shortly after that, they will return to the herd. Weaning age of the young varies between 6-17 months, and independence occurs at 2 years old. Males leave the herd at this time, but females usually remain. These matriarchal herds can break into separate ones when the number of individuals there grows too much. Usually the new herd will follow a female that is older than its other members. Sexual maturity is reached within 5 years and they have a lifespan of 25 years.
Отправлено: 26.07.23 02:25. Заголовок: I finished the descr..
I finished the description of the descendant of the Russian sturgeon: Southern sturgeon (Acipenser acanthodorsalis) Order: Acipenseriformes Family: Acipenseridae Habitat: Freshwater and estuarine areas of Southern and Southeastern South America, from Paraíba do Sul River to estuaries in Tierra del Fuego. Also present in rivers and estuaries of Chilean Patagonia. During the Holocene, humans had introduced species in new habitats due to different reasons. Some were introduced inadvertently, others as livestock, being new sources of food. The Russian sturgeon (Acipenser gueldenstaedtii) was produced in farms in Uruguay. From there, it was introduced accidentally in the Rio Negro, a tributary of the Rio de La Plata, and spread to Paraná River and reached Brazil. At the end of the Holocene, the fish had spread through the rivers and estuaries of the region. Now its descendant, the Southern sturgeon, is common to be found there. Being semi-anadromous, it inhabits freshwater and estuarine areas of Southern and Southeastern South America. This fish is one of the few sturgeon species that survived the anthropogenic onslaught. The Southern sturgeon is small for the standard of sturgeons: their length ranges from 70 to 100 cm, but rarely surpass 90 cm. This small size is the result of bootleneck effect. Their ancestors were small sized Russian sturgeons that were ignored by fishers. As a good adaptation, genes for small body length were passed down to their descendants. Its morphology is similar to that of their ancestor, with a relatively short and rounded snout with three pairs of unfringed barbels closer to the tip of the snout than to the mouth. The dorsal fin has 30 to 48 soft rays and the anal fin has 23 to 35. The number of scales along the lateral line varies from 25 to 50. The upper surface is grayish-green, the lateral scales are pale and the belly white. What differentiates this species from their ancestor is that the dorsal scutes are elongated, having a spike-like appearance. These scutes are 16-24 in number and can reach 20 cm in length. Such structure helps the fish protect itself against predators. This species feeds on crustaceans, molluscs, frogs and small fishes. Being capable of moving from freshwater to estuaries, the Southern sturgeon have a large number of prey at its disposal. To eat, these fishes will use its snout to probe the mud in the floor of rivers and estuaries. This process will scare the prey, which will be swallowed immediately. Adult Southern sturgeons usually inhabit estuaries, but they can also be found in rivers. They reproduce during the spring. To spawn, they migrate upstream in rivers. There, they’ll lay the eggs in a hard substrate, which offers both support and cover to their sticky and adhesive eggs. Males attain sexual maturity at 12–16 years of age, whereas females do so at 16–22 years. They will spawn every four to seven years. Southern sturgeons could migrate up to 1,000 km upriver to spawn. The female lays her eggs on gravel from 4 to 40 m underwater. Upon hatching, the embryo is 11 to 14 mm long, and 10–14 days later when they absorb their yolk sack, the length is 18 to 20 mm. Thereafter, the larvae usually subsist on benthic invertebrates, but when reaching at least 10 cm in length, they will switch to a fish-based diet. While swimming back to the estuaries, the young sturgeon may cover up to 60 km a day. The Southern sturgeon can live for 45 years.
Отправлено: 27.07.23 01:20. Заголовок: I finished the descr..
I finished the description of the rainbow trout's descendant: Red-bellied trout (Oncorhynchus macaensis) Order:Salmoniformes Family:Salmonidae Habitat: Endemic to the Macaé River basin and its tributaries The introduction of animals by humans in habitats that weren’t their own was one of the environmental calamities that affected the Holocene. These “invaders” outcompeted and preyed upon local fauna, leaving the trophic relations in disarray. With the arrival of the Neocene, the descendants of these became integrated in the ecological relations of these habitats. An example of it is the red-bellied trout, a descendant of rainbow trout (Oncorhynchus mykiss) that were introduced in the Macaé River in Brazil. This species evolved as an endemic fish of this river and its tributaries. An adult red-bellied trout typically ranges from 30 to 61 cm, but may be up to 91 cm. The males are larger than the females. Adults are generally blue-green or olive green with heavy black spotting over the length of the body. They have a distinctive pale pink belly, which becomes bright red during the breeding season. Until reaching their first year, the young have silver bellies with faint pink tones and a dark circle in their caudal fin that becomes pale gray in adults. These fishes are predators with a varied diet and will eat nearly anything they can capture. Red-bellied trout routinely feed on larval, pupal, and adult forms of aquatic insects. They also eat fish eggs and adult forms of terrestrial insects (typically ants, beetles, grasshoppers, and crickets) that fall into the water, as well as algae. Other prey includes small fish up to one-third of their length and crustaceans. The red-bellied trout spawn during the rainy season, with the adults migrating upstream in search of shallow waters with gravel bottoms. The trout form schools of thousands of fishes and several predators are attracted by this migration, using this “trout run” or “piracema” (a Tupi name for the migration of fish upstream to spawn) to catch these fishes in great abundance. Unlike some salmon, this trout is able to spawn several times. After the spawn, the adults will return to the river’s basin. Spawning sites are usually a bed of fine gravel in a riffle above a pool. The female clears a redd in the gravel by turning on her side and beating her tail up and down. They usually produce 2000 to 3000 eggs per kilogram of weight. During spawning, the eggs fall into spaces between the gravel, and immediately the female begins digging at the upstream edge of the nest, covering the eggs with the displaced gravel. As eggs are released by the female, a male moves alongside and deposits sperm over the eggs to fertilize them. The eggs usually hatch in about four to seven weeks although the time of hatching. In approximately two weeks, the yolk sac is completely consumed, and fry commence feeding mainly on zooplankton. The growth rate of red-bellied trout varies with quality and quantity of food. The red-bellied trout have a lifespan of 10 years, but many perish early and during the migration.
I found this article about exotic fishes in southern Brazil
I agree to you about Cyprinus carpio, Coptodon rendalli (and also other tilapias from Oreochromis genus) and Micropterus salmoides, but I think Clarias sp., Ctenopharyngodon idella, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis (in USA they're united under common name "asian carp"), and Ictalurus punctatus also can survive - they are invasive species that became a problem at many parts of the world.
Отправлено: 27.07.23 12:59. Заголовок: лягушка пишет: I ag..
лягушка пишет:
цитата:
I agree to you about Cyprinus carpio, Coptodon rendalli (and also other tilapias from Oreochromis genus) and Micropterus salmoides, but I think Clarias sp., Ctenopharyngodon idella, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis (in USA they're united under common name "asian carp"), and Ictalurus punctatus also can survive - they are invasive species that became a problem at many parts of the world.
What do you think if one of the Hypophthalmichthys becomes goldfish-sized? It could be a dwarf species of carp. Also the salmon Oncorhynchus tshawytscha was introduced in Patagonia and is now thriving in the region, going to the sea and returning to spawn in local rivers. Do you think that it could survive in the Neocene? I had another idea: the pacus introduced in Southeast Asia would evolve in a piranha-like species, while other would remain like their ancestors. Do you think that it's plausible?
Пост N: 1743
Откуда: Таллапнуджир, всякие ЛЮБАВЫ,ХВОСТЕНЫ, и т.д.
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Отправлено: 27.07.23 13:37. Заголовок: JOrnitho What do yo..
JOrnitho
цитата:
What do you think if one of the Hypophthalmichthys becomes goldfish-sized? It could be a dwarf species of carp.
But why? Niches of small cyprinids in South America are already occupied by characiniform fish, and also I think that downsizing won't be good fpr this fish - smaller size means more predation.
цитата:
Also the salmon Oncorhynchus tshawytscha was introduced in Patagonia and is now thriving in the region, going to the sea and returning to spawn in local rivers.
I think chinook salmon can survive in Patagonia and New Zealand, but only if it wouldn't be overfished by humanity during its decline (at first page of neocene project were said that humanity collapsed into mediveral level before dying out).
цитата:
I had another idea: the pacus introduced in Southeast Asia would evolve in a piranha-like species, while other would remain like their ancestors. Do you think that it's plausible?
Pacus already evolved into carnivorous forms in Meganesia, so they can do it in S.E. Asia.
Отправлено: 27.07.23 14:26. Заголовок: лягушка пишет: But ..
лягушка пишет:
цитата:
But why? Niches of small cyprinids in South America are already occupied by characiniform fish, and also I think that downsizing won't be good fpr this fish - smaller size means more predation.
I see. How do you think that their descendants will be? I already had some ideas for the Micropterus salmoides (an analogue of Amazonian peacock bass in temperate rivers) and the Cyprinus carpio (as a classic carp).
цитата:
I think chinook salmon can survive in Patagonia and New Zealand, but only if it wouldn't be overfished by humanity during its decline (at first page of neocene project were said that humanity collapsed into mediveral level before dying out).
If humanity collapsed into Medieval level, it means that they'll not be able to used modern ships and industrial machines to fish salmon in large scale. This way there'll be less pressure over them. I think that populations in Patagonia and New Zeland would survive because of it, but they would be affected by the bootleneck effect because there would be a reduction in their population, before it grew up again.
Отправлено: 27.07.23 02:25. Заголовок: лягушка I found this..
лягушка I found this articleabout exotic fishes in southern Brazil. Which one of these do you think that could survive in the region? I think that Cyprinus carpio, Coptodon rendalli and Micropterus salmoides are good candidates.
Отправлено: 28.07.23 04:34. Заголовок: I finished the descr..
I finished the description of the Patagonian salmon. I'll work on the description of the New Zealand species next.
Emperor salmon (Oncorhynchus imperator) Order:Salmoniformes Family:Salmonidae Habitat: South Atlantic and Pacific oceans, including the Antarctic Ocean. Adults spawn in rivers of Southern South America, from Tierra del Fuego to Maipo River in the West side of the continent and to Jacuí River in the East side. During the Holocene, humans had introduced species in new habitats due to different reasons. Some were introduced inadvertently, others as livestock, being new sources of food. The Chinook salmon (Oncorhynchus tshawytscha) was introduced in South America with the purpose of being produced as a food source. Inevitably, some individuals escaped and started to reproduce in Patagonia. During the decline of humanity, this species suffered pressure as a source of food, due to having stayed mostly in freshwater during the planktonic collapse, but was able to survive and their population recovered. However, its decline and eventual recovery resulted in a bootleneck effect over these fishes. Due to that, its descendants' genetic pool comes from a small number of survivors. In the Neocene, the Chinook salmon gave rise to the Emperor salmon, an inhabitant of cold waters of Southern Oceans. The adults spawn in rivers of Southern South America, from Tierra del Fuego to Maipo River in the West side of the continent and to Jacuí River in the East side. An adult emperor salmon has an average length of 70 to 120 cm, but the maximum length is about 150 to 180 cm. This fish is blue-green on the back and on the top of the head, with white ventral surfaces. They have a red stripe that runs on their sides, from the posterior part of the eyes to the base of the tail. This strip becomes brighter during the breeding season. It has black spots on its tail and the upper half of its body. The tail is silver. The diet of the emperor salmon varies according to their age. Juvenile fishes eat zooplankton, insects and even ctenophores. As adults, they eat smaller fish. Among the predators of this species are seabirds, larger fishes and squids. The young are among the preferred prey of Southern sturgeons that inhabit Patagonian rivers. Like their ancestors, the emperor salmon is euryhaline, and thus live in both saltwater and freshwater environments throughout their life. Once hatching, they spend three to twelve years in the ocean before returning to their home rivers to spawn. The salmon undergo radical morphological changes as they prepare for the spawning event ahead. Salmon lose the silvery blue they had as ocean fish, and their color darkens, sometimes with a radical change in hue. Emperor salmon is sexually dimorphic, with the male developing canine-like teeth, and their jaws develop a pronounced curve or hook called a "kype”. A more dominant male salmon have a reproductive advantage as females are often more aggressive toward smaller males. Like their ancestor, the emperor salmon spawn in larger and deeper waters. They can be found in the spawning areas from late summer to early winter. The female salmon may lay her eggs in four to five nesting pockets. After laying eggs, females guard the nests from four to 25 days before dying, while males seek additional mates. The eggs hatch 90 to 150 days after deposition, depending upon water temperature. Egg deposits are timed to ensure the young salmon fry emerge during an appropriate season for survival and growth. Fry and young fishes usually stay in fresh water for 12 to 18 months before traveling downstream to estuaries, where they remain as smolts for a year. After this period, they depart to the open sea. Some individuals return to freshwater one or two years earlier than their counterparts. They are typically less than 61 cm long but are sexually mature. The lifespan of the emperor salmon is twelve years, the age that most of them return to spawn and die shortly after. They are parasited by Myxozoans.
Пост N: 1756
Откуда: Таллапнуджир, всякие ЛЮБАВЫ,ХВОСТЕНЫ, и т.д.
Рейтинг:
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Отправлено: 28.07.23 07:53. Заголовок: JOrnitho Good fish!..
JOrnitho Good fish! Looks like Oncorhynchus rastrotus. And also add the fact that they stayed into fresh waters during planktonic disaster and survived due that.
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