The bluebuck (Afrikaans: bloubok ) or blue antelope (Hippotragus leucophaeus) is an extinct species of antelope that lived in South Africa until around 1800. It was smaller than the other two species in its genus Hippotragus, the roan antelope and sable antelope. The bluebuck was sometimes considered a subspecies of the roan antelope, but a genetic study has confirmed it as a distinct species.
The largest mounted bluebuck specimen is tall at the withers. Its horns measure along the curve. The coat was a uniform bluish-grey, with a pale whitish belly. The forehead was brown, darker than the face. Its mane was not as developed as in the roan and sable antelopes; its ears were shorter and blunter, not tipped with black; and it had a darker tail tuft and smaller teeth. It also lacked the contrasting black and white patterns seen on the heads of its relatives. The bluebuck was a grazer, and may have calved where rainfall, and thus the availability of grasses, would peak. The bluebuck was confined to the southwestern Cape when encountered by Europeans, but fossil evidence and rock paintings show that it originally had a larger distribution.
During the Late Pleistocene, the bluebuck was common across South Africa, but by the time Europeans encountered the bluebuck in the 17th century, it was already uncommon, perhaps due to its preferred grassland habitat having been reduced to a range, mainly along the southern coast of South Africa. Sea level changes during the early Holocene may also have contributed to its decline by disrupting the population, and it appears that it may have adapted for a low effective population size. The first published mention of the bluebuck is from 1681, and few descriptions of the animal were written while it existed. The few 18th-century illustrations appear to have been based on stuffed specimens. Hunted by European settlers, the bluebuck became extinct around 1800; it was the first historically recorded species of large African mammal to face extinction. Only four mounted skins remain, in museums in Leiden, Stockholm, Vienna, and Paris, along with horns and possible bones in various museums.
Taxonomy
According to German zoologist Erna Mohr's 1967 book about the bluebuck, the 1719 account of the Cape of Good Hope published by the traveler Peter Kolbe appears to be the first publication containing a mention of the species. Kolbe also included an illustration, which Mohr believed was based on memory and notes. In 1975, Husson and Holthuis examined the original Dutch version of Kolbe's book and concluded that the illustration did not depict a bluebuck, but rather a greater kudu (Tragelaphus strepsiceros), and that the error was due to a mistranslation into German. The first published illustration of the bluebuck is therefore instead a depiction of a horn from 1764. It has also been pointed out that the animal had already been mentioned (as "blaue Böcke") on a list of South African mammals in 1681.
The Welsh naturalist Thomas Pennant made the next published illustration, and included an account of the antelope, calling it "blue goat", in his 1771 Synopsis of Quadrupeds, based on a skin from the Cape of Good Hope purchased from Amsterdam. In 1778, a drawing by the Swiss-Dutch natural philosopher Jean-Nicolas-Sébastien Allamand was included in Comte de Buffon's Histoire Naturelle; he called the antelope tzeiran, the Siberian name for the goitered gazelle (Gazella subgutturosa). The illustration is widely believed to be based on the specimen in Leiden. This drawing is the first published illustration that shows the entire animal. Another record of the bluebuck appears in the travel memoirs of French explorer François Levaillant, published in the 1780s, describing his quest to discover the land to the east of the Cape of Good Hope, "Hottentots Holland". The German zoologist Martin Lichtenstein wrote about the bluebuck in 1812, but the species was mentioned less frequently in subsequent literature.
In 1776, the German zoologist Peter Simon Pallas formally described the bluebuck as Antilope leucophaeus. In 1853, the Dutch zoologist Coenraad Jacob Temminck stated that the type specimen was an adult male skin now in the Naturalis Biodiversity Center in Leiden (formerly Rijksmuseum van Natuurlijke Historie), collected in Swellendam and present in Haarlem before 1776. It has been questioned whether this was actually the type specimen, but in 1969, the Dutch zoologists Antonius M. Husson and Lipke Holthuis selected it as the lectotype of a syntype series, as Pallas may have based his description on multiple specimens.
In 1846, the Swedish zoologist Carl Jakob Sundevall moved the bluebuck and its closest relatives to the genus Hippotragus; he had originally named this genus for the roan antelope (H. equinus) in 1845. This revision was commonly accepted by other writers, such as the British zoologists Philip Sclater and Oldfield Thomas, who restricted the genus Antilope to the blackbuck (A. cervicapra) in 1899. In 1914, the name Hippotragus was submitted for conservation (so older, unused genus names could be suppressed) to the International Commission on Zoological Nomenclature (ICZN) with the bluebuck as the type species. However, the original 1845 naming of the genus with the roan antelope as a single species was overlooked and later suppressed by the ICZN, leading to some taxonomic confusion. In 2001, the British ecologist Peter J. Grubb proposed that the ICZN should rescind its suppression of the 1845 naming and make the roan antelope the type species of Hippotragus, since too little is known about the bluebuck for it to be a reliable type species. This was accepted by the commission in 2003.
The common names "bluebuck" and "blue antelope" are English for the original Afrikaans name "blaubok" . The name is a compound of blauw and bok ("male antelope" or "male goat")."Blauwbok, n." Dictionary of South African English. Dictionary Unit for South African English, 2018. Web. 25 February 2019. Variants of this name include "blaawwbok" and "blawebock". The generic name Hippotragus is Greek for "horse-goat", while the specific name leucophaeus is a fusion of two Greek words: leukos ("white") and phaios ("brilliant").
Preserved specimens
Four mounted skins of the bluebuck remain: the adult male in Leiden, a young male at the Zoological Museum of Stockholm, an adult female in the Vienna Museum of Natural History, and an adult male in the Museum of Natural History in Paris. A mounted skin was housed in the Zoological Museum in Uppsala until the 19th century, but now only the horns remain. There are also records of a skin in Haarlem, but its current whereabouts are unknown. Several of these skins have been identified in various 18th-century illustrations. Skeletal remains have been found in both archaeological and palaeontological contexts.
In 2021, the German geneticist Elisabeth Hempel and colleagues examined ten bluebuck specimens to resolve their identities, and found that only four of them were bluebucks. The skins in Stockholm and Vienna were confirmed as belonging to bluebucks, as were skull fragments in Leiden that may belong to the lectotype specimen, and the horns in Uppsala. Four assigned skulls (those in Glasgow, Leiden, Paris and Berlin) were shown to belong to either sable or roan antelopes, as were two pairs of horns (in Cape Town and St. Andrews). As a result, the bluebuck is rarer in museum collections than previously thought, and no complete skulls are known of the species. The researchers pointed out that there are four more potential specimens that could be confirmed through testing; two skulls in Berlin, a pair of horns in London, and either a skull or pair of horns in Brussels. In 2023, the pair of horns in London were confirmed by Hempel and colleagues to belong to a blue antelope using ancient DNA, but four other candidates were shown to be roan antelopes.
Evolution
Based on studies of morphology, the bluebuck has historically been classified as either a distinct species or as a subspecies of the roan antelope. After its extinction, some 19th-century naturalists began to doubt its validity as a species, with some believing the museum specimens to be small or immature roan antelopes, and both species were lumped together under the name A.leucophaeus by the English zoologist George Robert Gray in 1821. The Austrian zoologist Franz Friedrich Kohl pointed out the distinct features of the bluebuck in 1866, followed by Sclater and Thomas, who rejected the synonymy in 1899. In 1974, the American biologist Richard G. Klein showed (based on fossils) that the bluebuck and roan antelope occurred sympatrically on the coastal plain of the southwestern Cape from Oakhurst to Uniondale during the early Holocene, supporting their status as separate species.
In 1996, an analysis of mitochondrial DNA extracted from the bluebuck specimen in Vienna by South African biologist Terence J. Robinson's and colleagues showed that it was outside the clade containing the roan and sable antelopes. The study therefore concluded that the bluebuck is a distinct species, and not merely a subspecies of the roan antelope as was supposed. In 2017, a reconstruction of the entire bluebuck mitogenome by Portuguese biologists Gonçalo Espregueira Themudo and Paula F. Campos, based on bone powder extracted from the horns in Uppsala, contradicted the 1996 results. This study instead placed the bluebuck as a sister species to the sable antelope, with the roan antelope as an outgroup. The bluebuck and sable antelope diverged from each other 2.8 million years ago, while the roan antelope diverged from both of them 4.17 million years ago. Africa was going through climatic oscillations between 3.5 and 2 million years ago, and during a colder period, the ancestors of the sable antelope and bluebuck may have been separated, and the population in southern Africa eventually became a new species.
The cladograms below shows the placement of the bluebuck according to the 1996 and 2017 DNA studies:
Robinson and colleagues, 1996:
Themudo and Campos, 2017:
Based on their larger sample of specimens, Hempel and colleagues also found the bluebuck genetically closest to the sable antelope in 2021. This was confirmed by a 2022 study by Hempel and colleagues, which managed to sample DNA from a fossil bluebuck specimen for the first time, at 9,800–9,300 years old the oldest palaeogenome from Africa (the climate in South Africa is generally unfavourable to preserving ancient DNA).
Description
The adult male bluebuck in Leiden is tall at the withers, and is possibly the largest known specimen. According to Sclater and Thomas, the tallest specimen is the one in Paris, a male that stands at the shoulder; the specimen in Vienna, on the other hand, is the shortest, a tall female. The bluebuck was notably smaller than the roan and sable antelopes, and therefore the smallest member of its genus.
The coat was a uniform bluish-grey, with a pale whitish belly, which was not contrasted on the flanks. The limbs had a faint dark line along their front surface. The forehead was brown, darker than the face, and the upper lip and patch in front of the eyes were lighter than the body. The neck-mane was directed forwards and not as developed as in the roan and sable antelopes, and the throat-mane was almost absent. Other differences between the bluebuck and its extant relatives included its shorter and blunter ears not tipped with black, a darker tail tuft (though little darker than its general colour), and smaller teeth. The bluebuck also lacked the contrasting black and white patterns seen on the heads of its relatives.