Giraffe-like

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Giraffe-like
Okapi (Okapia johnstoni)

Okapi ( Okapia johnstoni )

Systematics
Subclass : Higher mammals (Eutheria)
Superordinate : Laurasiatheria
Order : Artiodactyla (Artiodactyla)
Subordination : Ruminant (Ruminantia)
without rank: Forehead weapon bearer (Pecora)
Family : Giraffe-like
Scientific name
Giraffidae
Gray , 1821

The giraffe-like (Giraffidae) are a family of the ungulates , which includes two genera , the giraffes and the okapi . They represent close relatives of the deer and horned bearers . In their external appearance, the two representatives differ quite clearly; Common connecting features can be found in addition to a specially pronounced canine tooth, among other things, in the formation of horn cones as forehead weapons. The family was founded in 1821 by John Edward Grayintroduced, but originally only contained the giraffes. Only with the discovery of the okapi in 1901 was another representative added. According to genetic studies, the giraffes now consist of three or four species in up to ten independent populations , whereas the okapi is only represented by one species.

The giraffe-like are endemic to Africa . While the okapi inhabits the tropical rainforests in the central part of the continent, the giraffes occur in the open savannah landscapes of the western, eastern and southern parts. The two genera therefore occupy different biotopes , their respective social structure is adapted to this. The okapi is predominantly a loner, the giraffes live in loose, unstructured herds. The diet is based primarily on soft vegetable food, with the giraffes being strongly associated with acacias . The giraffe-like are one of the few cloven-hoofed animals with a gestation period of over a year. Usually a single young is born.

The giraffe-like fossils have been known since at least the Lower Miocene . From a phylogenetic point of view, the family is very diverse; a larger part of its development took place outside Africa in southern Europe and from western to eastern Asia . The earliest forms were more deer-like in shape. Different lines of development emerged from them. In some of these, an extension of the neck is understandable, which means that they are probably in a direct predecessor of today's giraffes. In addition, the giraffe-like include extinct groups with voluminous bodies and short necks; the most important here are the Sivatheriinae .

features

Habitus

Southern giraffe ( Giraffa giraffa )

The giraffe-like are all large representatives of the artifacts and include the tallest land-dwelling mammals . The smaller Okapi ( Okapia ) has a head-trunk length of 200 to 210 cm plus a 30 to 42 cm long tail. The height to the top is about 180 cm, the body weight is 270 kg, with females being significantly heavier than males. In the case of the much larger giraffes ( Giraffa ), the head-trunk length can be 350 to 450 cm and the tail 60 to 110 cm long. The animals are 450 to 600 cm high to the top and about 310 cm to the shoulder . The weight varies from 450 to 1930 kg, with bulls being significantly heavier than cows. The two genera of the giraffe-like species differ somewhat in their physique, they have in common extensions in the neck and leg area, which are less pronounced in the okapi than in the giraffes. While the giraffes have an unmistakable appearance due to their extremely long neck and legs, the okapi looks more like a large antelope . The enormous neck extensions in the giraffes only start after birth. They go hand in hand with the stretching of the seven cervical vertebrae, including the rearmost one, so that the connection between the cervical and thoracic spine is further back than is usual with other ungulates . In normal running, the giraffes tend to keep their neck and head upright, only when running fast and when climbing mountain slopes are they both stretched forward. In contrast to this, the okapi has a more typical ungulate-like head posture. Both genera have horn-like bone cones covered with skin and fur that rise above the skull. The okapi has a pair of these horns, which mostly only occurs in bulls and whose tips are sometimes free of skin. In the giraffes, both sexes have a pair of horns on their heads, and there is seldom a pair of rear horns on the neck. However, male animals often have another, mostly smaller horn that grows in the middle between the eyes and is considered a secondary sex characteristic, but can also appear in cows. The long, dark tongue, which is very flexible and capable of grasping, is also striking. The coat is short with average hair lengths of 9.5 mm. Characteristic fur drawings appear, which in the giraffes consist of a dark spot or mosaic pattern in front of a light background. The generally darker, brown colored okapi shows light horizontal stripes on the legs. In both cases, the fur pattern can be associated with a defensive function. In terms of the overall appearance, the okapi proves to be a typical forest dweller, while the giraffes represent open land forms.

horns

Horns of a giraffe

A special characteristic of the giraffe-like are horn-like outgrowths on the head. In the giraffes, the pair of horns rises on the suture between the frontal and parietal bones , the front single horn on the frontal and nasal bones . With the okapis, on the other hand, the pair of horns sits on the frontal bone. Compared to similar formations in other forehead weapon bearers , the horns are not particularly large, in giraffes they reach a length of up to 19 cm with a circumference of 22 cm, in the okapi they are still 15 cm long. They are roughly conical in shape with a rounded tip and sit on a horn base that connects the structure to the skull. The horn bases are homologous to the corresponding formations in the horn carriers (Bovidae) or fork horn carriers (Antilocapridae). They contain air-filled bone chambers, some of which extend into the horns. The horns themselves have a firm, almost ivory- like structure inside . In contrast to the horns of the hornbeams, those of the giraffes do not have a keratin coating , but like these they represent permanent formations which, unlike the antlers of the deer (Cervidae), are not shed annually. Also unlike other horned cloven-hoofed animals , the horns develop in the embryonic stage . They are not initially connected to the skull and consist of spherical cartilage tissue that is embedded in the skin. Only in the course of individual development does the horn ossify from the tip and expand further until it grows together with the skull at around the age of four (males) to seven (females), although this happens later with the anterior horn than with the horn pair. After the horns have grown together with the base of the horn, there is only a slight increase in length due to bone rearrangement (secondary bone growth). This rearranged bone substance, which gives the horn a further growth of a maximum of 2 cm, covers the original horn structure and also buries the blood vessels within the horn. In principle, the pair of horns and the single front horn of the giraffes have a similar structure, but the latter is sometimes not as distinct. The pair of horns is sometimes referred to as Vellericorni (from the Latin vellus for "wool" and cornu for "horn") to separate similar formations from other forehead weapon bearers; the technical name Giraffacornu (as much as " Giraffe Horn ”), but this is not generally recognized.

Features of the skull and teeth

Skull of a giraffe
Molars of Palaeotragus with the typical selenodontic occlusal surface pattern

The skull is strikingly large compared to other ungulates and can be up to 73 cm long in giraffes. However, the sexual dimorphism is very pronounced, so that the skull of males can weigh up to 12 kg, in females the value is only a third of that. The okapi has a skull about 46 to 52 cm long. The extensive air-filled chambers in the skullcap, which occur primarily in the eye region of the frontal bone and also in the nasal bone and parietal bone, are striking. The chambers increase the volume of the skull without increasing the weight significantly. The lower jaw is long and narrow. The dentition consists of 32 teeth together and has the following dental formula : . As a result, analogous to other forehead weapon carriers, the front teeth are missing in the upper dentition. In the lower jaw, the incisors protrude obliquely forwards, they are spatulate and form a row like a segment of a circle. The lower canine tooth is widened and notched in adult individuals, so that two or three points emerge, which distinguishes the giraffe-like from other cloven-hoofed animals. The tips are able to shred leaves and twigs. The molars have a square shape, the crowns are low ( brachyodont ) and the chewing surface has a selenodontic pattern, i.e. the enamel ridges form crescent-shaped ribs along the longitudinal edge of the tooth.

Skeletal features

Skeleton of a giraffe
Comparison of the cervical spine of okapi (left) and giraffes (right)

One of the most striking features of the giraffe-like is the long neck of the giraffe, the bony base of which is about half the length of the entire spine. Typically, the cervical spine in mammals consists of seven vertebrae; what is striking in giraffes is the homogeneous structure of the individual cervical vertebrae compared to the more variable in okapi. The individual vertebrae are very stretched in the giraffes, they are 17 to 35 cm long, with the maximum being reached in the middle of the neck (in the Okapi the cervical vertebrae are between 9 and 13 cm long in comparison). In addition, the first thoracic vertebra in the giraffes is markedly elongated and only has a short spinous process , which makes it more similar to the cervical vertebrae. However, typical of mammals, it has the first rib attachment. The actual transition from the cervical to the thoracic spine is therefore shifted to the second thoracic vertebra. It is therefore sometimes argued that the giraffe's neck functionally consists of eight vertebrae. The feature is characteristic of giraffes and does not occur in the okapi or some other extinct representatives of the giraffe-like species such as Sivatherium . Possibly this serves the higher mobility of the neck of the giraffes. In tribal history, the stretching of the cervical spine began very early. The first forms with an elongated neck have been identified with Giraffokeryx as early as the Middle Miocene around 14 million years ago . Intermediate forms to today's giraffe then appear in the Upper Miocene, for example with Samotherium and Bohlinia , the former already had cervical vertebrae lengths of 16 to 23 cm. The stretching of the individual cervical vertebrae did not take place evenly and took place first in the front part of the vertebra, only later did the rear part also lengthen and finally flow into the vertebral structure known today of the giraffes. In contrast, there were also some fossil representatives in which the eddies shortened in the course of development, for example in the giant Sivatheriinae . The lengthening of the neck of the giraffes went hand in hand with the reduction in the size of the horns and the corresponding neck muscles for carrying such forehead weapons.

As with all cloven-hoofed animals , the central axis of the hand and foot runs through rays III and IV. In the area of ​​the metapodia , the two rays are fused together in the giraffe-like and form the cannon leg . This is extremely long and slim, it can reach up to 75 cm in length for the giraffes and up to 33 cm for the okapi. The laterally applied rays are strongly reduced and functionless, whereby the inner (ray II) occurs more frequently than the outer (ray V). In contrast to the horned bearers and the deer , the adjoining phalanges (fingers and toes) have completely regressed.

distribution

The giraffe-like are now restricted to Africa , but in the geological past they occurred over large areas of Eurasia . They currently inhabit the areas south of the Sahara . The giraffes have a rather spotty distribution over western , eastern and southern Africa. They occur in a variety of different open landscapes , ranging from shrubbery to forest savannas. Their association with acacia or deciduous vegetation is particularly characteristic . Their relative independence from water also enables them to survive in very arid landscapes. In contrast, the okapi is limited to the tropical rainforests and open forest-savanna mosaic landscapes of the Congo Basin in central Africa. However, they do not appear in gallery forests or very swampy regions.

way of life

Territorial and social behavior

Reticulated giraffe ( Giraffa reticulata )

The two representatives of the giraffe-like species belong to different ecological types due to their different habitat requirements. As a result, their respective way of life deviates significantly from each other, which is also known from other groups of ungulates such as the horned animals and the deer . The okapi represents a forest dweller, so it is solitary and rarely occurs in groups of up to three individuals. The animals maintain individual territories of 3 to 13 km² in size, although these are larger for bulls than for cows. The territories of male and female animals overlap, special places are marked with an oily secretion from the skin, and the animals defecate or urinate in defined places. Male animals defend their territory. In contrast, giraffes can be found in open landscapes, where the animals form loose herds consisting of cows and their offspring. Male animals can be found in "bachelor groups", and mixed herds are also known. Overall, however, the herds do not have a fixed structure and sometimes only exist for a few days. As a result, the animals are not territorial and do not defend their areas of activity . Their size varies from 25 to 160 km², in very dry areas they can reach up to 1950 km². The borders are often marked by rivers. In normal running, both the giraffes and the okapi move forward in the pace , with the neck swinging characteristically, especially in the former, according to studies by Anne Innis Dagg , which helps balance.

nutrition

Maasai giraffe ( Giraffa tippelskirchi )

Both the giraffes and the okapi feed mainly on the leaves of dicotyledonous plants ( browsing ). The animals eat very selectively and often prefer the freshest parts of the plant, which have a high proportion of proteins as well as calcium and phosphate , for the latter they have a high need due to their strong bone growth. The okapi eats more than 100 different plant species with a dominance of about 20, which cover a large number of plant groups, such as mallow family or ebony family as well as representatives of the Putranjivaceae . The food spectrum of the giraffes includes up to 77 plant species, but the giraffes are more specialized and eat fewer than a dozen of these regularly. A special preference is given to acacias and long threads . Giraffes and okapis use their long, flexible tongues to pluck the leaves. Both genera are also bound to mineral licks, especially giraffes sometimes chew on bones. Giraffes are also water-dependent, but they can do without water for several days.

Reproduction

In general, reproduction is not tied to certain seasons, but in giraffes it can preferably take place in the growth phase of the acacia. Bull giraffes engage in advertising battles using the long neck and heavy head; these fights can sometimes lead to serious injuries. This rather unusual fighting behavior probably originated with the lengthening of the neck of the giraffes. Such behavior has not yet been documented in okapis. The gestation period is 14 to 15 months, usually a young is born, rarely twins. Giraffe mothers usually leave the herd at birth. The calf escapes from the nest , but initially remains in a hiding place for several weeks. The mother-cub relationship lasts for around 9 to 14 months.

Systematics

External system

Internal systematics of the recent cetartiodactyla according to Zurano et al. 2019
 Cetartiodactyla  
  Suina (pig-like)  

 Tayassuidae (umbilical pigs)


   

 Suidae (real pigs)



   

 Camelidae (camels)


   
 Cetancodonta  

 Hippopotamidae (hippos)


   

 Cetacea (whales)



 Ruminantia (ruminant)  

 Tragulidae (deer piglets)


  Pecora (forehead weapon bearer)  

 Antilocapridae


   

 Giraffidae (giraffes)


   

 Cervidae (deer)


   

 Moschidae (musk deer)


   

 Bovidae (hornbeams)










Template: Klade / Maintenance / Style

The giraffe-like are a family from the order of the cloven-hoofed animals (Artiodactyla). Within the even-toed ungulate they belong in turn to the group of ruminants (Ruminantia), whose members have a multi-chambered stomach . This is subordinate to the taxon of the forehead weapon bearer (Pecora), whose special feature is the formation of horns and antlers. This represent about the deer (Cervidae), the Bovidae (Bovidae), the musk deer (Moschidae) and the Gabelhorn carrier (Antilocapridae) the closest relatives of the giraffe-like. While morphological studies within the frontal armor bearer various relationships showed and the giraffe-like with both the Gabelhorn carriers group with the horned bearers or with the deer, molecular genetic analyzes speak for a closer relationship with the deer, musk deer and the horned beard, whereby the giraffe-like then stand in a sister group relationship to these. The extensive splitting of the forehead weapon carriers occurred in the transition from the Oligocene to the Miocene around 24 million years ago, the diversification within the giraffe-like then began in the course of the Middle Miocene around 15 million years ago. The immediate close relationship of the giraffes like the Climacoceratidae are summarized in the superfamily of the Giraffoidea , groups a little further away, such as the Palaeomerycidae , are in the Giraffomorpha .

Internal system

Today's giraffe-like are composed of two subfamilies. One, the giraffinae , contains the giraffes and is defined by the elongated cervical vertebrae, the long limbs with the same metapodia , which lack longitudinal grooves on the back of the metacarpal bones , as well as the square ankle bone and the horns, with the rear pair having a blunt keel has at the back and an unpaired front single horn also occurs. The other subfamily, the Okapinae , includes the Okapi, defining features are the medium-long metapodia with weak posterior longitudinal indentation of the metacarpal bones, horns with internal canals and a large tympanic sac . Other classifications lead both genera within the Giraffinae and differentiate them on the rank of the tribe .

There are also several extinct subfamilies. Among them is the Sivatheriinae or cattle giraffes, the best known, which is relatively rich in shape and includes large animals with a strong body and short neck, large frontal sinuses and two pairs of horns. They were widespread across Eurasia and Africa and came from the Upper Miocene to the Pleistocene . Another important and widespread group are the Palaeotraginae , Samotheriinae and Bohlininae consisting of large, long-limbed animals with one or two pairs of horns, which appeared predominantly in the Middle and Upper Miocene in the Old World.

Overview of the genera and species of the giraffe-like

The following genera and species are assigned to today's giraffe-like:

  • Family: Giraffidae Gray , 1821
  • Subfamily: Okapinae Bohlin , 1926
  • Genus: Okapia Lankester , 1901
  • Okapi ( Okapia johnstoni ( Sclater , 1901))

The genus Okapia is monotypical and contains the okapi as the only species. Several species were described at the beginning of the 20th century, but today these are all synonymous with the actual okapi. In contrast, only one species was recognized within the genus Giraffa in the course of the 20th century, which then included up to nine subspecies. Molecular genetic studies from 2007 only showed a low gene flow between these subspecies. The authors of the studies therefore advocated splitting the genus into six species. Inferring from these analyzes, Colin Peter Groves and Peter Grubb raised eight subspecies to species status in a revision of the ungulates in 2011. A DNA study presented in 2016 was able to identify four monophyletic groups within the Giraffa genus , which should therefore be classified as actual species. These are the north giraffe , the south giraffe , the reticulated giraffe and the Maasai giraffe . In 2020, this was reduced to three species as part of a further genetic analysis, which, however, include a total of ten subspecies (one of which is extinct). In contrast to the four-species model, the reticulated giraffe in this three-species model is a subspecies of the northern giraffe. Again, genetic studies from 2021 conclude four separate species, largely comparable to the results from 2016, with a total of seven subspecies.

Other subfamilies and genera are known to fossils:

  • Genus: Praepalaeotragus Godina, Vislobokova & Andrachmanova , 1993
  • Genus: Palaeotragus (+ Akhtiaria , Macedonitherium , Mitilanotherium , Orlovia , Sogdianotherium , Yuorlovia ) Gaudrey , 1861
  • Subfamily: Okapinae Bohlin , 1926
  • Subfamily: Giraffokerycinae Solounias , 2007
  • Genus: Helladotherium (+ Panotherium , Maraghatherium ) Gaudry , 1860
  • Genus: Karsimatherium Meladze , 1962
  • Genus: Brahmatherium (+ Hydaspitherium , Vishnutherium ) Falconer , 1845
  • Genus: Sivatherium (+ Libytherium , Indratherium , Griquatherium , Orangiatherium ) Falconer & Cautley , 1836

Tribal history

Origins

Live reconstruction of Xenokeryx's head

Giraffes were once a much more species-rich group than they are today. Ancestors of the family are found in the Palaeomerycidae and Climacoceratidae , both of which were common in Eurasia and Africa and largely occurred in the Lower and Middle Miocene . Both families were deer-like in shape and, like the giraffes, had fur-covered horns, a pair of which rose above the eyes. In the Palaeomerycidae, a third, single horn was attached to the back of the skull , which was partly forked like Xenokeryx from the Middle Miocene of western Europe. The Climacoceratidae also had antler-like bifurcated horns, some of which developed bizarre shapes such as Prolibytherium , but they also had a notched lower canine tooth, which is a typical appearance of the giraffe-like. On the other hand, they had already reduced the upper canine tooth. They are possibly closer to the giraffe-like than the Palaeomerycidae.

Miocene

One of the earliest representatives of the giraffe-like species is partially counted Progiraffa , which has its earliest occurrence in the Siwaliks in Pakistan , where it is proven in the Lower Miocene about 18 million years ago. The shape is documented by various sites in the Bugti Mountains. As a rule, dentition fragments are mostly present, but horn cones and parts of the skull as well as individual elements of the body skeleton have also come down to us. The position of Progiraffa within the giraffe-like species is not entirely clear; sometimes a close relationship with Prolibytherium is seen. However, the Canthumerycinae with their type form Canthumeryx, which appear around the same time period, clearly belong to the giraffe-like species . This was partly named as Zarafa , the Arabic original word (زرافة, ( zarāfah )) for the "giraffe". Fossils were first found in North Africa, for example at Gebel Zelton in Libya , others are from the Lothidok Formation in East Africa and the Arabian Peninsula . The animals were about the size of a fallow deer and had short, conical horns that attached above and behind the eyes and diverged sharply from one another. A close relative of Canthumeryx was Georgiomeryx , which was passed down from the Greek island of Chios in the Middle Miocene and whose horns had a flatter structure, but also protruded laterally. Around the same time, in the Middle Miocene, giraffes appeared for the first time, which already had significantly elongated cervical vertebrae and long bones. These include Giraffokeryx from the Giraffokerycinae group , the remains of which were found in Fort Ternan in Kenya , in Çandır in Anatolia and in the Chinji formation of the Siwaliks in Pakistan. It had two pairs of horns, of which the horns of the front were short and round in cross-section, those of the rear were long and flat.

Skull of Samotherium
Skull of Honanotherium

Two important groups are the Palaeotraginae and the Samotheriinae , which were particularly dominant in the Upper Miocene. Outwardly they include medium-sized to large animals similar to the okapi with a pair of unbranched, pointed horns. Palaeotragus occurred over large parts of Eurasia and Africa and was a very long-lived form that existed from the Middle Miocene to the Lower Pleistocene . It was characterized by slightly elongated limbs and a stretched neck and had a broad skull, which, however, lacked the typical giraffe-like frontal sinuses. Finds came to light in Thermopigi in northern Greece , among other places . There are also remains of Samotherium from here. The latter shape was much more modern and larger. Their elongated skull was more similar to that of today's giraffes, the neck already exceeded that of the okapi and the shape of the cervical vertebrae approximated the corresponding bones of the giraffes. The type finds of Samotherium come from the Greek island of Samos , where its fossil bones, along with those from the horse-like Hipparion and some early goat representatives, are among the most common finds from that time. The distribution of the genus was very wide, however, individual skulls have come down to us from Maragheh in Iran and from the Linxia Basin in the Chinese province of Gansu , among others . There Samotherium occurred in the Upper Miocene together with Shansitherium . Both representatives of the giraffes were similar in their skeletal structure, but differed, among other things, in the structure of the horns, which were fused at the base in Shansitherium , but not in Samotherium .

Skull of Decennatherium

In the group of Bohlininae, in turn, Bohlinia belongs , a form developed in the phylogenetic history which, apart from the giraffes, had the longest neck and the longest legs in the family, as well as two erect horns. The Bohlininae were very widespread, with Bohlinia mainly coming from southern Europe and western Asia, significant finds were found in Kirokuçuk in North Macedonia , in Nikitri in the Greek region of Macedonia and in Pikermi also in Greece. Other representatives such as the small and original Injanatherium , which had laterally protruding horns, were limited to western Asia. Honanotherium, on the other hand, comes from central and eastern Asia, the extensive remains of Maragheh in Iran should be emphasized here. Another quite common representative in Europe is Decennatherium . Several skulls and an almost complete skeleton have been reported from Batallones-10 near Torrejón de Velasco near Madrid in Spain , among others . The skeletal find indicates an animal with a body height of 2.8 m, a body length of 2.9 m and a weight of possibly 1190 kg. In terms of skeleton structure, the shape largely coincided with the Samotheriinae and Bohlininae, the massive horns with numerous ridges, however, approached the large Sivatheriinae . In addition, representatives of the modern lines have come down to us in the Upper Miocene. This includes, on the one hand, Afrikanokeryx from the group of Okapiinae , which is documented through parts of the skull and fragments of the lower jaw from Ngorora in western Kenya. The finds date to an age of about 9 million years. In addition, the Giraffinae are also detectable for the first time . The origin of today's long-necked giraffes is not clear. A derivation of Palaeotragus is advocated partly on the basis of tooth and skull morphological features , but the skeletal anatomy also supports a descent from Bohlinia . The oldest fossil finds of the genus Giraffa come from the Upper Siwaliks in South Asia and are around 7.5 million years old, older finds from the Middle Miocene are sometimes viewed as problematic.

The earliest evidence of the Sivatheriinae or cattle giraffes, which formed a successful side branch of the giraffe-like and includes extremely large, strong and short-necked animals with two pairs of horns, also falls in the Upper Miocene. The early forms include Helladotherium from eastern and southeastern Europe, such as Thermopigi in Greece, and Brahmatherium from the Siwaliks. The latter achieved a very wide distribution and is documented from both Southeast Asia and West Asia . The Sivatheria underwent a progressive adaptation to a clumsy walk in more open landscapes, for example by shortening the metapodia , which is a contrary trend to numerous other giraffes. They also preferred a more mixed vegetable diet with a higher proportion of hard grass.

Pliocene and Pleistocene

Live reconstruction of Sivatherium

In Eurasia, the Palaeotraginae in particular persisted. So Palaeotragus until well into the Early Pleistocene of Sesklo detectable in Greece, where, among others, a nearly complete skull was found with about 30 cm long horns. In the Pliocene, however, the genus was widespread over large areas of southern Europe and central Asia. Sivatherium , the character form of the Sivatheria, developed into a huge animal with the stature of a buffalo and with two pairs of horns, the rear of which was shaped like a shovel. It had a body weight of around 1250 kg. The shape was described in 1836 as the first extinct representative of the giraffe-like using a massive skull from the Siwaliks. It is regularly documented there in the form of remains of teeth, but has also been found at numerous fossil sites in Eurasia, including in Stamer près de Delcevo in north-western North Macedonia. In addition, finds are known from Africa, for example from Langebaanweg in southwestern South Africa . In the transition from the Upper Miocene to the Pliocene, Giraffa also reached the African continent, where it developed its own lines of development, which both led to today's species and include dwarf forms. The long-necked giraffes inhabited large parts of eastern, southern and sometimes central Africa in the Pliocene and Pleistocene. They are relatively well documented in Koobi Fora and in the Olduvai Gorge in East Africa, among others .

Research history

John Edward Gray (1800-1875)

Carl von Linné put the giraffes with the then only known representative, today's northern giraffe , in the tenth edition of his work Systema naturae in 1758 under the name Cervus camelopardalis to the deer . This was corrected four years later by Mathurin-Jacques Brisson by creating the genus Giraffa . The official introduction of the genus Giraffa was for a long time awarded to Morten Thrane Brünnich , who used the name in 1772, but a decision of the ICZN in 1998 changed this in favor of Brisson. The scientific genus name Giraffidae, which in turn comes from John Edward Gray in 1821, is based on Giraffa . His short feature description of the family was: frontal bone in Both sexes lengthened into two solid, conical, permanent processes, covered with a permanent, hairy skin "extended frontal bone strength in both sexes to two, conical, permanent appendages covered with lasting Fell" ( ). In 1825, Gray introduced the name Camelopardina as a subgroup of horn-bearers , while six years later Charles Lucien Jules Laurent Bonaparte founded the family Camelopardalidae (the generic name Camelopardalis goes back to Johann Christian von Schreber , who wrote this in 1784 in his work Die Used mammals in images of nature with descriptions , Pieter Boddaert also used them only a year later). Especially in the 19th century, the family assignment Camelopardalidae was partially used. There has been hardly any debate about the systematic position of the giraffe-like species since Linnaeus was first named the species. He had placed today's northern giraffe within the genus Cervus together with the genera Bos , Capra , Ovis and Musk (plus Camelus ) in the group of forehead weapon bearers (Pecora). However, the exact relationship to the other representatives of the forehead weapon bearers was not undisputed. A closer relationship to the hornbeams (Bovidae) or to the deer (Cervidae) was sometimes preferred. In the course of the 19th century, the giraffes were mostly regarded as a recently monotypical family with only the giraffes as the only recognized representative of the species. It wasn't until the discovery of the okapi in 1901 that they were given another one.

literature

  • John M. Harris, Nikos Solounias and Denis Geraads: Giraffoidea. In: Lars Werdelin and William Joseph Sanders (eds.): Cenozoic Mammals of Africa. University of California Press, Berkeley, Los Angeles, London, 2010, pp. 797-811
  • Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (Eds.): Mammals of Africa Volume VI. Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids. Bloomsbury, London 2013, pp. 95-115
  • JD Skinner and G. Mitchell: Family Giraffidae (Giraffe and Okapi). In: Don E. Wilson and Russell A. Mittermeier (Eds.): Handbook of the Mammals of the World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, ISBN 978-84-96553-77-4 , pp. 788-802

Individual evidence

  1. ↑ Sybrand J. van Sittert, John D. Skinner and Graham Mitchell: From fetus to adult - an allometric analysis of the giraffe vertebral column. Journal of Experimental Zoology B 314, 2010, pp. 469-479
  2. ↑ a b c d C. A. Spinage: Horns and other bony structures of the skull of the Giraffe and their functional significance. East African Wildlife Journal 6, 1968, pp. 53-61
  3. ^ Anne Innes Dagg: External features of giraffe. Mammalia 32, 1968, pp. 657-669
  4. ↑ a b c d e G. Mitchell and JD Skinner: On the origin, evolution and phylogeny of giraffes Giraffa camelopardalis. Transactions of the Royal Society of South Africa 58 (1), 2003 pp. 51-73
  5. ↑ a b c d e f J. D. Skinner and G. Mitchell: Family Giraffidae (Giraffe and Okapi). In: Don E. Wilson and Russell A. Mittermeier (Eds.): Handbook of the Mammals of the World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, ISBN 978-84-96553-77-4 , pp. 788-802
  6. ↑ a b c d e f g h Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume VI. Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids. Bloomsbury, London 2013, pp. 98-110
  7. ↑ a b c Ray Lankester: On Okapia, a new Genus of Giraffidae, from Central Africa. Transactions of the Zoological society of London 1902 (2), pp. 279-315
  8. ↑ a b N. Solounias and N. Tang: The two types of cranial appendages in Giraffa camelopardalis (Mammalia, Artiodactyla). Journal of Zoology London 222, 1990, pp. 293-302
  9. ↑ CA Spinage: The median ossicone of Giraffa camelopardalis. Journal of Zoology London 230, 1993, pp. 1-5
  10. ^ Anne Innes Dagg: Sexual differences in the giraffe skull. Mammalia 29, 1965, pp. 610-612
  11. ^ A b Richard E. Bodmer and George B. Rabb: Okapia johnstoni. Mammalian Species 422, 1992, pp. 1-8
  12. ↑ N. Ludos Badlangana, Justin W. Adams and Paul R. Manger: The giraffe (Giraffa camelopardalis) cervical vertebral column: a heuristic example in understanding evolutionary processes? Zoological Journal of the Linnean Society 155, 2009, pp. 736-757
  13. ↑ Melinda Danowitz and Nikos Solounias: The Cervical Osteology of Okapia johnstoni and Giraffa camelopardalis. PLoS ONE 10 (8), 2015, p. E0136552, doi: 10.1371 / journal.pone.0136552
  14. ↑ Ray Lankester: On certain points in the structure of the cervical vertebrae of the okapi and giraffe. Proceedings of the Zoological Society of London 1908, pp. 320-334
  15. ↑ N. Solounias: The remarkable anatomy of the giraffe's neck. Journal of Zoology London 247, 1999, pp. 257-268
  16. ↑ Marilena A. Müller, Luisa JF Merten, Christine Böhmer and John A. Nyakatura: Pushing the boundary? Testing the “functional elongation hypothesis” of the giraffe's neck. Evolution, 2021, doi: 10.1111 / evo.14171
  17. ↑ Melinda Danowitz, Aleksandr Vasilyev, Victoria Kortlandt and Nikos Solounias: Fossil evidence and stages of elongation of the Giraffa camelopardalis neck. Royal Society open science 2, 2015, p. 150393, doi: 10.1098 / rsos.150393
  18. ↑ a b Melinda Danowitz, Rebecca Domalski and Nikos Solounias: The cervical anatomy of Samotherium, an intermediate-necked giraffid. Royal Society open science 2, 2015, p. 150521, doi: 10.1098 / rsos.150521
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