Отправлено: 06.08.22 20:05. Заголовок: Fauna of Islands of the Indian Ocean

Starting a new topic because this doesn't fit the already existing ones about islands (Atlantic and Pacific).
I saw in the map of the Neocene that Adaman and Nicobar still exist, so I thought about some species that could exist here. Since it was a chain of islands, I think that the fauna could be different in each of them. For example, the largest one (Adaman itself) could have maintained large introduced species such as the chital deer and feral dogs. These animals would have descendants in the Neocene.
Meanwhile in Great Nicobar, terrestrial predators could be absent and the largest animal could be a flightless descendant of the Nicobar pigeon .
What do you think?

 Отправлено: 02.02.23 20:20. Заголовок: JOrnitho Good ones!..

JOrnitho
Good ones!

 Отправлено: 02.02.23 14:29. Заголовок: Yes, really interest..

Yes, really interesting flying squirrels!

 Отправлено: 03.02.23 00:38. Заголовок: Finished the rats: ..

Finished the rats:

Striped coconut rat (Palmaromys striatus)
Order: Rodentia
Family: Muridae
Habitat: Forests of Great Andaman and nearby islands
During their expansion, the humans had inadvertently transported several commensal species with them. The black rat (Rattus rattus) was one of the animals that became widespread thanks to anthropogenic expansion. The populations of Andaman and Nicobar had survived into the Neocene, giving rise to genus Palmaromys, the coconut rats. The main representative of the genus is the striped coconut rat, an inhabitant of Great Andaman and nearby islands.

The striped coconut rat has a head-to-body length of 18 cm and a prehensile tail of 22 cm. Their underparts are white. It has reddish-brown fur on its upper body and two dark brown stripes contrasting with light brown stripes along its back. They have strong incisors and powerful muscles in the head, which allow them to break the thick shell of coconuts and seeds. Another characteristic of the Palmaromys as a genus is that they developed cheeck pouches that are used to carry food back to their dens. It’s usually shared by them.

This species is omnivorous, but they have a preference for coconuts. They also eat soft fruits, seeds, flowers, insects and eggs. The striped coconut rat has an arboreal lifestyle, rarely descending to the ground. When foraging, they can travel several kilometers per night from where their dens are located.

The striped coconut rat is nocturnal and monogamous. The male and female form family groups with their youngest offspring. These groups inhabit the same den, which is usually inside a hollowed tree or rock crevice. The family leave their dens during the dusk and disperse to seek food, usually the parents will remain together. During the entire night, they will vocalize to each other to maintain contact. Some are loud, while others are ultrasonic.

They breed during the entire year, with the female producing up to five litters a year. The gestation period is only 21 days, and litters can number up to 14, although seven is more common. They reach sexual maturity in about five weeks, but the young will remain with their parents until reaching one month. During this period, they help take care of their siblings. A "babysitter" will remain at the den with the young, while the others leave to eat. In these cases, the parents will return with some food for them inside of their cheeck pouches. The lifespan of this species is 2 years.

Another representative of the genus Palmaromys is the Spectacled coconut rat (Palmaromys nicobarensis), an inhabitant of Great Nicobar and nearby islands. This species has a head-to-body length of 15 cm and a prehensile tail of 19 cm. Their underparts are whitish-yellow. It has dark brown fur on its upper body and white markings across its face, which gives them a "spectacled" appearance.

 Отправлено: 03.02.23 09:35. Заголовок: Interesting animal!..

Interesting animal!

 Отправлено: 03.02.23 10:31. Заголовок: JOrnitho Very good ..

JOrnitho
Very good rats! But the name... Maybe, you meant striped, which means "decorated with stripes"? Because "stripped" is a past participle of "to strip" (same as "to undress").

 Отправлено: 03.02.23 11:55. Заголовок: Биолог пишет: Becau..

Биолог пишет:

цитата:

Because "stripped" is a past participle of "to strip" (same as "to undress").

Thanks! I corrected it.
Now only the description of the coconut remains.

 Отправлено: 04.02.23 15:25. Заголовок: Another island that ..

Another island that could have an interesting fauna is Comoros. The mongoose lemur (Eulemur mongoz) was introduced here and live well in the forests. Maybe a descendant of this species could live there in the Neocene?

 Отправлено: 04.02.23 20:45. Заголовок: JOrnitho Why not?..

JOrnitho
Why not?

 Отправлено: 06.02.23 14:08. Заголовок: Besides the descenda..

Besides the descendant of the lemurs, Comoros could have a descendant of pigs with dwarfism and a feline with size of a fossa, which would hunt the pig and the lemurs. Any ideas for more animals?

 Отправлено: 06.02.23 18:45. Заголовок: JOrnitho пишет: Any..

JOrnitho пишет:

цитата:

Any ideas for more animals?

As I know, caecilians also live there. What is their conservation status?

 Отправлено: 06.02.23 22:22. Заголовок: Автор Of which spec..

Автор
Of which species? I like the idea of caecilians, we really lack them in Neocene. And they definitely could survive in their underground burrows.

 Отправлено: 06.02.23 22:56. Заголовок: I'll need to sea..

I'll need to search about the caecilians, but I think that rather than having a predatory cat, it could be a descendant of the Javan mongoose, which was also introduced in Comoros. It could still become a fossa-like animal.

 Отправлено: 07.02.23 10:51. Заголовок: JOrnitho A fossa-li..

JOrnitho
A fossa-like mongoose is interesting.

 Отправлено: 07.02.23 21:02. Заголовок: Another idea that I ..

Another idea that I had is for a most frugivorous descendant of the also introduced small Indian civet (Viverricula indica). Having the appearance of a very small fox, it would also be prey of the fossa-like mongoose.

 Отправлено: 07.02.23 23:08. Заголовок: JOrnitho You mean a..

JOrnitho
You mean a frugivorous animal would become a predator?

 Отправлено: 08.02.23 02:43. Заголовок: Биолог пишет: You m..

Биолог пишет:

цитата:

You mean a frugivorous animal would become a predator?

No, I mean that the small Indian civet (Viverricula indica), an omnivorous species, could have a fox-like descendant that became more frugivorous. This new species of viverrid would be preyed by the fossa-like mongoose.

 Отправлено: 08.02.23 09:00. Заголовок: JOrnitho OK...

JOrnitho
OK.

 Отправлено: 10.02.23 03:58. Заголовок: I'm working in t..

I'm working in the descriptions for the animals of the Comoros Islands, but after reading more I concluded that each island would have their own endemic fauna. They are far away enough to avoid animals swimming between them.

 Отправлено: 10.02.23 12:51. Заголовок: I think that the onl..

I think that the only animals that can spread to other islands are small ones, moving through rafting. This way, I thought that there could be a descendants of the brown rat that evolved to become analogues of the macropodes. They would have large hindfeet and would move by jumping. The largest species would have the size of a small wallaby.

 Отправлено: 11.02.23 04:33. Заголовок: Finished the descrip..

Finished the description of three animals for Comoros Islands, the rest comes later after I finish working on it.

Comoros dwarf hog (Parvosus sociabilis)
Order: Artiodactyla
Family: Suidae
Habitat: Forests and woodlands of Ngazidja Island
During their expansion, the humans had transported several domesticated animals with them. Among them was the domestic pig (Sus domesticus), which was capable of surviving in the Comoros Islands. Their descendant is the Comoros dwarf hog, a small and highly gregarious omnivore that inhabits Ngazidja, the largest island of the archipelago.

The Comoros dwarf hog is one of the smallest Suids of the Neocene, with an adult having 28 cm of height and 72 cm of length. They have a striking reddish-brown fur, with black legs and a tufted dark brown stripe along the spine. They have several white mottles around their fur. Besides being slightly larger than females, the males have the upper canines visible on the sides of their mouths.

This species is diurnal and forage for food during the daylight hours. Foraging usually takes place for about 10 hours a day, with the hog generally taking a break midday in order to escape the high heat of the afternoon. Dwarf hogs are also omnivorous and feed primarily on roots, tubers, fallen fruits and other vegetative food, as well as on insects, rodents, eggs, young birds, and small reptiles.

The dwarf hogs are social animals that live in large family groups consisting of several females and their offspring. They are non-territorial, and sometimes family groups can consist of as many as 40 individuals. Adult males are generally solitary and live separately rather than with the family group. Subadult males form bachelor groups for protection. However, they do maintain loose contact with the basic family group throughout the year.

They make firm nests in which to sleep by digging small trenches, using dry grasses and vegetation to line them. They sleep in these nests at night, but also retreat to these nests during the heat of the day,

The mating season starts during the end of winter, with males doing displays of strength against each other to achieve the right of mating. The gestation period varies according to the age of the expecting mother. For first-time breeders, it lasts 114 days, while it lasts 133 days in older ones. The average litter consists of 4–6 piglets, with the maximum being 10–12. The piglets are whelped in a nest constructed from twigs, grasses and leaves. These nests are similar to those used by them to sleep at night. Should the mother die prematurely, the piglets are adopted by the other sows in the sounder. Their average lifespan is between 8 and 14 years and they become sexually mature at two years old.


False fossa (Urvatrox tyrannica)
Order: Carnivora
Family: Herpestidae
Habitat: Forests and woodlands of Ngazidja Island
During their expansion, the humans had introduced several species. The Javan mongoose (Urva javanica) was left by them on the Comoros Archipelago, where they survived to the transition between the Holocene and Neocene. Their descendant is the false fossa, the great predator of the forests of Ngazidja, the largest island of the archipelago.

As their name says, the false fossa is morphologically similar to the Eupleridae predator that lived in Madagascar during the Holocene. Adults have a head-body length of 75 to 90 cm, with the males being larger than the females. It has semi-retractable claws (meaning it can extend but not retract its claws fully) and flexible ankles that allow it to climb up and down trees head-first, and also support jumping from tree to tree. This is an example of convergent evolution with their Malagasy distant relative. Their fur is dark reddish-brown, with a prominent black tip on their tails.

The false fossa is the top predator of Ngazidja. They feed on birds and mammals, including the dwarf hog and the fox civet. However, their main prey is the Spectacled lemur, which they actively hunt through the trees. While they can kill young and sick Ngazidja kangaroo-rat, the false fossa avoids healthy adults due to their powerful kicks and bites.

This species is active during both the day and the night, with activity peaks occurring early in the morning, late in the afternoon, and late in the night. The false fossa generally does not reuse sleeping sites, but females with young do return to the same den. The territory ranges of males and females overlap, but females usually have separated ranges. Except for mothers with young, these animals are usually found alone, so that the species is solitary.

The mating season starts during the spring. The males will enter the territory of a receptive female and when rivals find each other, they will vocalize and make antagonistic interactions. Occasionally those can end in violent fights. Females are pregnant for up to 90 days and give birth to a litter of 2 to 5 young, usually inside a concealed location, such as an underground den, a termite mound, a rock crevice, or in the hollow of a large tree. The newborns are blind and toothless. After about two weeks the cubs' eyes open, they become more active. The cubs do not take solid food until three months old, and do not leave the den until they are 5 months old. They are weaned shortly after that. After the first year, the juveniles are independent of their mother. Sexuall maturity is reached by about two years of age and their lifespan is of 18 years, but some males can die early due to wounds sustained during fights in the mating season.

Spectacled lemur (Eulemur elegantulus)
Order: Primates
Family: Lemuridae
Habitat: Forests and woodlands of Ngazidja
During their expansion, the humans had introduced several species. The mongoose lemur was left by them on the Comoros Archipelago, where they survived to the transition between the Holocene and Neocene. Their descendant is the spectacled lemur, an animal endemic to the forests of Ngazidja, the largest island of the archipelago. They are also the only species of lemur that live outside of Madagascar.

Spectacled lemur is a medium-sized lemur with a head-to-body length of 39 cm and a tail length of 55 cm. Like their ancestors, this species is sexually dichromatic. Males have a reddish-brown dorsal coat which darkens as it reaches the hands, feet and base of the tail. Ventral coat is pale gray and the tail is dark brown. The nose, muzzle and face are black, with white tufts in the ear and cheek. The females have a gray-brown dorsal coat which darkens to gray around the shoulders and upper area of the back to the top of the head. The ventral coat is a paler gray, and the face is black with white tufts in the cheeks and ear. Tail is often darker than the dorsal coat and can range in color from gray-brown to dark gray. Both sexes have white markings across its face, which gives them a "spectacled" appearance.

The diet of this species consists primarily of fruit, but includes other plant parts such as buds, young leaves and flowers, varying according to seasonal availability. It also includes occasional invertebrates. They can forage in the forest ground, but only do it in the presence of other animals such as the dwarf hog and the Ngazidja kangaroo-rat.

Spectacled lemur troop sizes range from 6 to 15 individuals, numbers varying depending on location. Each troop defends a territory of up to 15 hectares, and will chase off intruding groups with territory calls rather than defending home ranges violently. Differently from most of their relatives in Madagascar, their groups are led by a dominant male, who is the father of all young in the group. He will fight against solitary males that try to invade his territory.

They are the main prey of the false fossa. In the presence of these predators, they will flee through the trees with great agility.

Mating occurs in early autumn and births usually take place in early spring after a gestation of about 120 days. Typically only one young is born, but they can occasionally produce twins. As with most true lemur species, newborn Sanford's Lemurs cling to the mother's chest at first and after about two weeks they transfer onto her back. The young may be weaned by three or four months of age and they reach sexual maturity at two years. The males are expelled from the group at this age and they form bachelor gangs for protection against predators. This species has a lifespan of 20 years.