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. 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.

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"). 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

thumb|Skin in [[National Museum of Natural History (France)|National Museum of Natural History, Paris]]

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.

Evolution

thumb|upright|Horns in [[Natural History Museum, London]]

Based on studies of morphology, the bluebuck has historically been classified as either a distinct species or as a subspecies of the roan antelope. 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:

Description

upright|thumb|left|Head of the Vienna skin

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 horns of the bluebuck appear to have hollow pedicles (bony structures from which the horns emerge).

Behaviour and ecology

thumb|Illustration of a male and female (background), by [[Joseph Smit|Smit and Wolf, from before 1899; the image may be based on the Paris skin, and the neck-mane is perhaps depicted as too long.]]

The bluebuck, as Klein puts it, became extinct before "qualified scientists could make observations on live specimens". According to historical accounts, the bluebuck formed groups of up to 20 individuals. Similarities to the roan and the sable antelopes in terms of dental morphology make it highly probable that the bluebuck was predominantly a selective grazer, and fed mainly on grasses. The row of premolars was longer than in others of the genus, implying the presence of dicots in the diet. A 2013 study by the U.S. paleontologist J. Tyler Faith and colleagues noted the scarcity of morphological evidence to show that the bluebuck could have survived the summers in the western margin of the Cape Floristic Region (CFR), when the grasses are neither palatable nor nutritious. This might have induced a west-to-east migration, because the eastern margin receives rainfall throughout the year while precipitation in the western margin is limited to winter. Rock paintings in the Caledon river valley of the Free State province in eastern South Africa have been identified as bluebucks, which also confirms the once wider distribution of the species. therefore the rise in sea levels with the beginning of the Holocene would have led to fragmented bluebuck populations and distanced many populations from the western coast (fossils dating to this period are scarce in the western coast but have been recorded from the southern coast). Thus, a mass extinction could have taken place, leaving behind mainly the populations that remained in the resource-rich western CFR.

Faith and colleagues further suggested that the bluebuck, being a grazer, probably favoured grassland habitats. Kerley and colleagues suggested that the bluebuck frequented grasslands and shunned wooded areas and thickets.

Relationship with humans

Extinction

right|upright|thumb|Head by [[Thomas Pennant|Pennant, 1771, the second published illustration of this species

thumbtime=1:48|thumb|Dutch [[newsreel about taxidermy from 1978 showing the Leiden specimen]]

The bluebuck was hunted to extinction by European settlers; in 1774 Thunberg noted that it was becoming increasingly rare. The German biologist Hinrich Lichtenstein claimed that the last bluebuck had been shot in 1799 or 1800. Around the time of its extinction, the bluebuck occurred in what would be known as the Overberg region (Western Cape), probably concentrated in Swellendam. In 1990, the South African zoologist Brian D. Colohan argued that an 1853 eyewitness report of a "bastard gemsbok" seen near Bethlehem, Free State, actually referred to a bluebuck, 50 years after the last individuals in Swellendam were shot.

Cultural significance

The bluebuck rock paintings from the Caledon river valley have been attributed to Bushmen. They show six antelopes facing a man, and were supposedly inspired by shamanic trance; they may depict a Bushman visiting the spirit-world through a tunnel. The Bushmen possibly believed that the bluebuck had a supernatural potency, like other animals in their environment. The animals in the paintings are similar in proportion to the reedbuck, but the large ears, horns, and lack of a mane rule out species other than the bluebuck.

A South African fable, The Story of the Hare, mentions a bluebuck (referred to as inputi) that, among other animals, is appointed to guard a kraal. The bluebuck is also mentioned in French novelist Jules Verne's Five Weeks in a Balloon (1863); the animal is described as a "superb animal of a pale-bluish colour shading upon the gray, but with the belly and the insides of the legs as white as the driven snow".

References

Citations

Sources

  • Interactive 3D scan of the Vienna specimen at Sketchfab
  • Blue Antelope Correspondences