This idea is partially inspired by discussion surrounding the brown hyena in the DLC speculation thread. Basic idea of this thread is to create a pack containing species that are rare (or even absent) in zoos that you personally still think would be really neat to have. Species should be rare in zoos globally - for example, while there are no bilbies kept outside Australia, they are very common in Australian zoos and therefore do not count. Purely hypothetical of course, just to get the listing juices flowing and showcase some more obscure animals.
For me, I'd go with:
1. Grey Four-eyed Opossum (Philander opossum)
A species of didelphid opossum seems necessary at some point for filling out marsupial representation, and while Virginia opossum is the obvious choice I personally find South and Central American species much more interesting. Unfortunately, all are also rare in zoos. The grey four-eyed opossum at least has one holding outside of the Americas, being held in an aquarium (strangely) in Russia, and I've also managed to find one zoo in Mexico (Zoomat) that keeps them - however, I assume they may be found in some smaller Latin American collections too. It's also one of my favourite opossum species for reasons I can't quite grasp - I just like their vibe.
2. Numbat (Myrmecobius fasciatus)
A very distinctive Australian marsupial, part of its own family and with an important conservation story, but unfortunately very rare in zoos even in Australia. In fact the entire captive population is practically owned by Perth Zoo, which has a large number of them and is the only zoo that breeds them. All other numbats that have appeared in other zoos in Australia in recent years have been retired breeders from Perth - I saw such individuals at Cleland Wildlife Park and Alice Springs Desert Park, but the individuals at both zoos have now passed away. Currently a single female at Wild Life Sydney is the only numbat kept outside of Perth Zoo to my knowledge. Still, it's probably the animal on this list I want the most.
3. Black-footed Tree-rat (Mesembriomys gouldii)
Now this is an animal I guarantee 95% of you haven't heard of. Getting an Australian rodent would be awesome, and the black-footed tree-rat is one of the largest (around the size of a capuchin) and the most beautiful. It also provides representation for the tropical savannah woodlands of northern Australia, which currently have nothing but the dingo and saltie in game (both of which are much more widespread and therefore aren't as "characteristic" of that ecosystem). In terms of IRL captive presence, the species is currently only kept at Perth Zoo and Territory Wildlife Park, both in Australia.
4. Leopard Seal (Hydrurga leptonyx)
The only animal on this list not currently kept in any zoos, despite my usual preference for species that have at least some captive presence I can't help but include this big beautiful boi. They're one of my absolute favourite animals and including them in zoos in places where they regularly wash up (Australia, New Zealand, Patagonia etc) is not actually entirely unrealistic. The only zoo to keep them this century to my knowledge was Taronga Zoo, which had 3 of them - the last, named Casey, was unfortunately euthanised in 2014.
5. Brown Hyena (Parahyaena brunnea)
I love hyenas, and the brown hyena is my favourite of them all. They've just got such an interesting appearance, and this coupled with the desolate landscape they live in makes them extremely cool animals. However, they are only found in 5 zoos outside of Africa to my knowledge (2 in Europe and 3 in Central America), and I imagine their captive presence on their native continent isn't very strong either. Still, they're probably the animal on this list with the greatest captive presence, even if they do still qualify as a rare species in zoos.
6. Grandidier’s Vontsira (Galidictis grandidieri)
Why just have the fossa when there are all sorts of cool small carnivorans from Madagascar? The genus Galidictis contains two particularly attractive species of small striped predators, of which only one, the Grandidier's vontsira, is currently kept in zoos to my knowledge. Still, their current captive holdings seem restricted to Magdeburg Zoo in Germany and Chester Zoo in the UK, making them a very rare animal indeed. We currently have no animals endemic to the arid spiny forests of Madagascar, and thus this would be a great species to represent the area.
7. South Island Takahē (Porphyrio hochstetteri)
The third and least famous member of New Zealand's rotund bird trio, the South Island takahē is rare in zoos compared to the much more famous kiwis but at least has a captive presence, unlike the kākāpō. Currently it is restricted to New Zealand zoos, with 4 different holdings. As well as providing desperately needed representation for New Zealand, the takahē is also the only member of the rail family I feel has even a slight chance of making into the game, so it'd be a good pick in a taxonomic sense too. Plus, who wouldn't want the grand orb in their game?
8. Pygmy Bluetongue Skink (Tiliqua adelaidensis) [E]
Purely a personal bias pick, this unique and endangered lizard is endemic to my local region and only kept at Adelaide Zoo (where I have seen them) and Monarto Safari Park (off-display) to my knowledge, where they have recently set up a captive breeding program. I'm going to be lucky enough to do some fieldwork with this species in the wild later on this week which only makes my bias towards them stronger. Their habit of living in abandoned spider holes would make for quite a unique exhibit - they couldn't just be chucked into the arid box like every other Australian reptile so far.
For me, I'd go with:
1. Grey Four-eyed Opossum (Philander opossum)
A species of didelphid opossum seems necessary at some point for filling out marsupial representation, and while Virginia opossum is the obvious choice I personally find South and Central American species much more interesting. Unfortunately, all are also rare in zoos. The grey four-eyed opossum at least has one holding outside of the Americas, being held in an aquarium (strangely) in Russia, and I've also managed to find one zoo in Mexico (Zoomat) that keeps them - however, I assume they may be found in some smaller Latin American collections too. It's also one of my favourite opossum species for reasons I can't quite grasp - I just like their vibe.
2. Numbat (Myrmecobius fasciatus)
A very distinctive Australian marsupial, part of its own family and with an important conservation story, but unfortunately very rare in zoos even in Australia. In fact the entire captive population is practically owned by Perth Zoo, which has a large number of them and is the only zoo that breeds them. All other numbats that have appeared in other zoos in Australia in recent years have been retired breeders from Perth - I saw such individuals at Cleland Wildlife Park and Alice Springs Desert Park, but the individuals at both zoos have now passed away. Currently a single female at Wild Life Sydney is the only numbat kept outside of Perth Zoo to my knowledge. Still, it's probably the animal on this list I want the most.
3. Black-footed Tree-rat (Mesembriomys gouldii)
Now this is an animal I guarantee 95% of you haven't heard of. Getting an Australian rodent would be awesome, and the black-footed tree-rat is one of the largest (around the size of a capuchin) and the most beautiful. It also provides representation for the tropical savannah woodlands of northern Australia, which currently have nothing but the dingo and saltie in game (both of which are much more widespread and therefore aren't as "characteristic" of that ecosystem). In terms of IRL captive presence, the species is currently only kept at Perth Zoo and Territory Wildlife Park, both in Australia.
4. Leopard Seal (Hydrurga leptonyx)
The only animal on this list not currently kept in any zoos, despite my usual preference for species that have at least some captive presence I can't help but include this big beautiful boi. They're one of my absolute favourite animals and including them in zoos in places where they regularly wash up (Australia, New Zealand, Patagonia etc) is not actually entirely unrealistic. The only zoo to keep them this century to my knowledge was Taronga Zoo, which had 3 of them - the last, named Casey, was unfortunately euthanised in 2014.
5. Brown Hyena (Parahyaena brunnea)
I love hyenas, and the brown hyena is my favourite of them all. They've just got such an interesting appearance, and this coupled with the desolate landscape they live in makes them extremely cool animals. However, they are only found in 5 zoos outside of Africa to my knowledge (2 in Europe and 3 in Central America), and I imagine their captive presence on their native continent isn't very strong either. Still, they're probably the animal on this list with the greatest captive presence, even if they do still qualify as a rare species in zoos.
6. Grandidier’s Vontsira (Galidictis grandidieri)
Why just have the fossa when there are all sorts of cool small carnivorans from Madagascar? The genus Galidictis contains two particularly attractive species of small striped predators, of which only one, the Grandidier's vontsira, is currently kept in zoos to my knowledge. Still, their current captive holdings seem restricted to Magdeburg Zoo in Germany and Chester Zoo in the UK, making them a very rare animal indeed. We currently have no animals endemic to the arid spiny forests of Madagascar, and thus this would be a great species to represent the area.
7. South Island Takahē (Porphyrio hochstetteri)
The third and least famous member of New Zealand's rotund bird trio, the South Island takahē is rare in zoos compared to the much more famous kiwis but at least has a captive presence, unlike the kākāpō. Currently it is restricted to New Zealand zoos, with 4 different holdings. As well as providing desperately needed representation for New Zealand, the takahē is also the only member of the rail family I feel has even a slight chance of making into the game, so it'd be a good pick in a taxonomic sense too. Plus, who wouldn't want the grand orb in their game?
8. Pygmy Bluetongue Skink (Tiliqua adelaidensis) [E]
Purely a personal bias pick, this unique and endangered lizard is endemic to my local region and only kept at Adelaide Zoo (where I have seen them) and Monarto Safari Park (off-display) to my knowledge, where they have recently set up a captive breeding program. I'm going to be lucky enough to do some fieldwork with this species in the wild later on this week which only makes my bias towards them stronger. Their habit of living in abandoned spider holes would make for quite a unique exhibit - they couldn't just be chucked into the arid box like every other Australian reptile so far.
Aren't Ring Tailed Lemurs also living there or am I confusing it with a Environment that is just relatively similar?
so many died in Abidjan Zoo since 1993)
and a really nice looking Monkey. I love it. So adorable 
