The taxonomy of the Antwerp gorillas has often been discussed here on the forum, in several threads.
Antwerp Zoo has imported a number of gorillas, some of which are in the studbook - some are missing
There is mention of a gorilla in Antwerp Zoo as early as 1879 (Cousins, 1991)
In 1923 Ben Burbridge delivered a female gorilla Quahali that was caught in Virunga mountains to Antwerp Zoo - she died after a year
In 1925 Ben Burbridge delivered a male gorilla Marzo to Antwerp Zoo, also coming from Virunga (together with a female named Miss Congo who travelled on with Burbridge to America. Marzo died in Antwerp after a few months
see Cousins 1991, but also Newman's excellent book "Encountering gorillas"
In 1953 a male Gorilla Gust came to Antwerp from Cabinda, Angola. He would live until 1988, without leaving offspring. He was definitely Western lowland gorilla
Several female Western gorillas were also acquired which are mentioned in the studbook (Josephine in 1955 - died in 1956; Kora in 1957 - moved to Touroparc in 1989; Lea in 1958 - died in 1959; unnamed female in 1961, died in the same year; Xara in 1970, moved to Rotterdam in 1976)
Gust was very popular in Belgium, and many people believe they have seen Gust on the famous terraces in Antwerp Zoo's 1958 Ape House. However, after Gusts companion Kora tried to climb the walls of the enclosure, the pair of Western lowland gorillas was never allowed outside, according to Van Puyenbroeck 1989. After Gust died, his companion Kora was sent to France and Antwerp did not have Western gorillas for 14 years until 2002
But regarding the other "mountain gorillas": here we go
There have been numerous imports by Antwerp, but many of these individuals were never on show - although they are now in the studbook.
In 1957 males KAISI and KISUBI arrived through Mr Cordier. They were captured in the area around Walikale. In 1962 female PEGA, and in 1963 female QUIVUarrived - both also from the Walikale region. Kisubi and Quivu produced Victoria in 1968 - so she stems from 2 individuals originating from Walikale
Indeed, in the early days those gorillas were "branded" as mountain gorillas. We must remember that taxonomy is not a fixed fact, and gorilla taxonomy has changed several times - including the fairly recent of one species into two species. An excellent account is given by Colin Groves in 2002. He points out the many different subspecies that were originally described, until in 1928 Ernst Schwarz categorised them into seven (!) subspecies, all belonging to one species including the 4 taxa that are recognised (again) today (Gorilla gorilla gorilla, Gorilla gorilla diehli, Gorilla gorilla beringei and Gorilla gorilla graueri), but also other species such as Gorilla gorilla uellensis, Gorilla gorilla rex pygmaeorum and Gorilla gorilla matschiei, which are no longer recognised, and which also had many synonyms.
In 1929 this was revised by Coolidge who brought it down to one species with two subspecies: Gorilla gorilla gorilla for all Western gorillas, and Gorilla gorilla beringei for all Eastern gorillas. This classification remained unchanged until 1969. So in the days when Antwerp imported the 2.2 graueris - this was a taxon that no longer was recognised and they belonged to Gorilla gorilla beringei - "the mountain gorilla"
Then in 1967 Groves revised gorilla taxonomy once again, and came up with 3 subspecies, all belonging to the same species - Gorilla gorilla gorilla for Western lowland gorillas; Gorilla gorilla gorilla for Mountain gorillas and Gorilla gorilla graueri (which was first named Gorilla gorilla manyema), which included populations East of Lualaba.
Incidentally a paper in Antwerp Zoos member journal by Van Puijenbroeck 1977 discusses this and says that Kaisi, Kisubi, Quivu and Pega, as well as captive born VICTORIA belong to the grauers gorillas. In all following publications, Antwerp Zoo has labelled the animals as Grauers gorillas, or Eastern lowland gorillas, (Gorilla gorilla graueri).
In 1968 Victoria was born (Kisubi x Pega) and several more births occurred (to females Quivu and Pega) but none survived. Kaisi never reproduced succesfully.
Several other gorillas were imported by Antwerp
2 males and 2 females are were imported 1957-1958, (male Kambuti and Lando, females named Louli and Layla, all died between 1957 and 1960) and are listed as beringei in the studbook. I am not sure how accurate that is, since this is before the revised taxonomy.
The studbook mentions a male graueri gorilla VISOKE imported in 1968, who died in 1969. Van Puijenbroek 1977 shows a photo of a female VIRUNGA that was imported on the same day in 1968 and according to him clearly was mountain gorilla.
In 1978 Quivu died. Because Kaisi was not fertile, Kisubi was bred with his daughter which resulted in a succesful birth in 1981 of ISABEL. Isabel died in 1995.
In 1980 a male, named FLUP was imported, listed as graueri, died atfer two weeks. In 1983 male IGOR came from Burundi which caused a bit of international riot, as Dian Fossey wrote a complaint to IPPL Newsletter. Igor died in 1995, shortly after the arrival of Amahoro, and after he had taken over the dominant role of Mukisi.
In 1985 male MUKISI arrived from Chester. When the new ape house was constructed in 1988, a group was formed around Mukisi as breeding male, with adult females Pega and Victoria, and adolescents Igor and Isabel.
In 1995 a female arrived AMAHORO - usually discussions about the taxonomy of Antwerp gorillas revolve around her, rather than about Victoria - and people often wonder if Amahoro is not a mountain gorilla. This is usually based on her morphology, as she looked very different from Victoria and Mukisi.
Then genetic studies came about, initially for the D-loop of mitochondrial DNA by Garner & Ryder in 1996, showing great variability between the Western gorillas and the mountain and grauer's gorillas on the other hand. The article states that the difference is as large as between chimpanzees and bonobos. Samples from grauer's gorillas came from 2 captive individuals, as well as individuals from Kahuzi Biega. Incidentally this paper also looked at Mitochondrial DNA from Amahoro and found proof that her MtDNA matched with the gorillas from Kahuzi Biega, and therefore she was considered graueri, and this played a role in the decision to send her to Antwerp Zoo, the only place with a (potential) breeding group of grauer's gorillas. Amahoro was introduced but shortly after Igor and Isabel died, leaving young Amahoro with Mukisi and Victoria.
In 2001 Jensen-Seaman & Kidd analysed Mitochondrial DNA of Eastern gorillas; including 2 animals from Antwerp, including Mukisi + an unnamed individual (probably Victoria or Amahoro) as well as male Mkubwa from Houston and found all three captive individuals clustered with wild animals from Kahuzi Biega and Tshiaberimu, and clearly were different from the Bwindi and Virunga clade.
In 2001 Groves revised his taxonomy - and elevanted the Western gorillas to one species, Gorilla gorilla, with two subspecies - Gorilla gorilla gorilla, and the Cross river gorillas Gorilla gorilla diehli. The Eastern gorillas are the other species with two subspecies Gorilla beringei beringei for the gorillas inhabiting the Virunga mountains, and Gorilla beringei graueri for the others, but there was/is discussion about the Bwindi population, which is sometimes suggested to be as a separate subspecies from the G.beringei beringei ; and accorsing to some people also the Kahuzi Biega gorillas should be separate from the other graueri populations.
In 2002 Mukisi died, and Antwerp Zoo acquired a (sterile) Western silverback male from Artis named Kumba. Two female Western gorillas joined Kumba, Victoria and Amahoro in 2011 (Mambele) and 2014 (Esiankiki). In 2016 Kumba Victoria and Kiki died, . A new Western male Matadi arrived and was introduced to Amahoro the only graueri gorilla, and Mambele. In 2017 another Western female Mayani arrived and in 2018 and 2020 first offspring were born - in fact the first Western gorillas born in Belgium.
In 2007 Thalmann et al looked at DNA sequences from 16 noncoding autosomal loci from 15 western gorillas and 3 eastern gorillas, including 2 noninvasively sampled free-ranging individuals. The 3rd individual was Mukisi from Antwerp. The study concluded that our data suggest a complex history of western and eastern gorillas including an initial population split at around 0.9–1.6 MYA and subsequent, primarily male-mediated gene flow until approximately 80,000–200,000 years ago. Furthermore, simulations revealed that more gene flow took place from eastern to western gorilla populations than vice versa
