Hyrax

Hyrax
Bush hyrax ( Heterohyrax brucei )
Systematics
Class : Mammals (mammalia) Subclass : Higher mammals (Eutheria) Superordinate : Afrotheria without rank: Paenungulata Order : Hyrax Family : Hyrax
Scientific name of the  order
Hyracoidea
Huxley , 1869
Scientific name of the  family
Procaviidae
Thomas , 1892

The hyrax (Procaviidae) are a family within the order of the same name in German, the Hyracoidea . It is good rabbit large and the external appearance of marmots reminding members of the mammals . Their bodies and limbs are strong, the muzzle is short and the tail is hidden in the fur. A characteristic formation can be found on the back, where a conspicuous colored spot marks a gland . Also noticeable are the numerous whiskers that appear not only on the face but all over the body. The animals are endemic to Africa , the only exception is the hyrax also lives in the Middle East . The rock hyrax and the bush hyrax inhabit rocky, open and sometimes dry areas, while the tree hyraxes are adapted to forests. The habitat of the hyrax includes both flatlands and high mountain areas.

The animals can climb well and, thanks to a few adjustments to the foot, are also quick to move on steep, uneven or slippery terrain. The bottom-dwelling rock hyrax and bush hyrax live diurnally and form large family groups. In contrast, tree hybrids appear at night and are largely loners. All species behave territorially, the loud calls of the males are important. The main food of the hyrax consists of plants, the individual species differ in their preference for harder or softer components. Water is rarely drunk. The reproduction usually takes place once a year. Females have a very long gestation period . A litter contains one to four young animals.

The order of hyrax is relatively old, the earliest representatives are found in the Eocene almost 50 million years ago in both northern and southern Africa. In contrast to today's Schliers, the original forms were very varied. In addition to small animals, there were also giant ones weighing over a ton. The original hyraxes moved in the most varied of ways, running, jumping or climbing. As a result, they occupied a large number of habitats. By the Miocene at the latest, the hyrax reached Eurasia and spread far over both continents. However, the high variability was subsequently lost due to competition with other animal groups, mainly ungulates . Only the small representatives of the modern hyrax survived to this day. Because of their partly rich fossil finds and the numerous proven forms, the extinct hyrax are of great importance for the biostratigraphy of Africa.

The closest relatives of the hyrax are the proboscis and manatees . All three orders are summarized as Paenungulata , which in turn form part of the very heterogeneous group of Afrotheria . The exact relationships between hyraxes and other mammals have long been unclear. In the 18th century, when the first scientific reports about hyraxes were made, they were thought to be rodents . They were later frequently associated with various groups of ungulates. This resulted in an intense debate that took place in the course of the 20th century and in which the family relationships were discussed. On the one hand, scientists saw a connection between the hyrax and the odd-toed ungulate , and on the other, to the elephants . The dispute could only be resolved in the transition to the 21st century with the advent of biochemical and molecular genetic research methods. The family was scientifically named in 1892, the ordinal name had already been coined in 1869. With one exception, the population of the individual species is classified as not endangered.

features

Habitus

Rainforest tree hyrax ( Dendrohyrax dorsalis )

Today's hyrax are relatively small mammals about the size of a rabbit. Your head-torso length is between 32 and 60 cm. The tail is tiny and mostly barely visible, at most 3 cm long. Hyrax reach a weight of 1.3 to 5.4 kg. Differences between males and females are not pronounced. However, across the range, there are sometimes considerable variations in size within a species, some of which are environmental. Outwardly, today's hyraxes resemble guinea pigs . They are very robust, stocky animals, all of which are characterized by a muscular, short neck and a long, arched body. Their coat color varies according to genus and species and ranges from gray to light and dark brown to black, the belly often appears lighter. A gland on the back is covered by a patch of fur of a different color. The fur is short in the slivers of dry landscapes, but long and dense in the inhabitants of the forests and high alpine regions. It is interspersed with numerous vibrissae , the length of which is up to 30 mm. Other whisker hairs of up to 90 mm in length appear on the face. The hyrax's head is flattened, the muzzle generally short, as are the ears. The upper lip is split open. The eyes bulge forward, they have an additional shield or lid that pushes itself from the iris over the pupil in bright sunlight and is called the umbraculum . It enables the sleepers to look into the sun. Light spots sometimes appear on the face, for example on the eyebrows. The limbs are short, in front they end in four toes with small hooves. There are three toes on the hind legs, the innermost one has a curved claw, while hooves are formed on the other legs. The toes and fingers are united to the base of the last limb. The bare, often dark soles are penetrated by numerous glands.

Skull and dentition features

Skull of rock hyrax ( Procavia capensis )

The skull of the hyrax shows itself to be relatively generalized with a broad and flat forehead line, a vertically positioned occiput and sweeping zygomatic arches . In side view it reaches a relatively great height, more than half of which is taken up by the massive lower jaw. The rostrum is short and ends bluntly. Clear temporal lines appear on the parietal bones , which in the common hyrax ( Procavia ) can unite to form a crest , which is not particularly massive. The interparietal bone is a prominent bone , an element of the roof of the skull between the two parietal bones and the occiput. Depending on the type, a postorbital arch can be formed that closes the posterior edge of the orbit . This is about in the tree hyraxes ( Dendrohyrax the case), but not the hyrax and the yellow-spotted rock hyrax ( Heterohyrax ). As a unique feature of the hyrax, the parietal bone takes part at the end of the rear edge of the eye. The tear bone forms part of the eye socket. At the base of the skull, the glenoid pit for the joint of the lower jaw is formed by both the cheekbone and the temporal bone . The lower jaw is particularly noticeable because of its massive, wide and high ascending branch. The crown process only rises slightly above the articular process. At the rear end, the angled extension is clearly rounded.

The teeth of today's hyraxes have a slightly reduced number of teeth, which mainly affects the front teeth. It consists of a total of 34 teeth with the following tooth formula : . In some populations of the Klippschliefers, however, the lower first premolars have receded, so that only 32 teeth are formed in these. The upper incisor is growing permanently and is significantly enlarged. A clear sexual dimorphism can be seen in the shape of the tooth , as it is larger in males, triangular in cross-section and provided with a sharp front edge. Females, on the other hand, have a smaller and more rounded or flattened upper incisor. The lower incisors are flat, like a chisel, in the tree snakes each tooth is divided into three small pins so that a kind of tooth comb is created. In the other two species, the characteristic is less pronounced and often only present in the young stage. There is no canine , but it is formed in the deciduous dentition. There is a clear diastema to the rear dentition . The premolars and molars show differences between the species with regard to the crown height. The hyrax has high-crowned ( hypsodontal ) teeth, the other representatives are equipped with more or less low-crowned ( brachyodontal ) teeth. The molars in particular are somewhat reminiscent of those of the odd ungulate . The upper molars have two transverse enamel ridges (Protoloph and Metaloph) on the chewing surface, creating a bilophodontic pattern. Along the outer edge of the tooth, both strips are connected to one another by another (Ectoloph). As a result, the melting pattern appears π-shaped, an equivalent can be found in the rhinos . In contrast to the nahorns, the ectoloph is not continuous, but divided by a furrow. In the lower jaw, the molars show a double crescent shape, analogous to the rhinoceros. The change of teeth from deciduous to permanent dentition also takes place very late in the individual development of the sleepers, as in some other representatives of Afrotheria, often only in the adult and sexually mature stage. ${\displaystyle {\frac {1.0.4.3}{2.0.4.3}}}$

Skeletal features

Skeleton of the Klippschliefers

Hand (left) and foot (right) of a sleeper, the taxeopode (serial) arrangement of the carpal and tarsal bones is clearly visible

Individual peculiarities can also be found in the skeleton construction. The spine consists of 7 cervical, 19 to 22 thoracic, 6 to 9 lumbar, 5 to 7 sacrum and 4 to 10 tail vertebrae. As usual with the Afrotheria, the number of vertebrae (thoracic and lumbar vertebrae) is 27 to 30 higher than in other kin groups; within the Afrotheria the hyrax have the most individual elements. The lumbar spine is extremely elongated and with a length of 10 cm it reaches more than half the length of the thoracic spine, which measures around 15 cm. There are between 19 and 22 pairs of ribs, with 21 and 22 more common. Seven to eight pairs of these are connected to the sternum . A collarbone is not developed. The acrominion is also missing on the shoulder blade , instead the shoulder bone gradually tapers off. The ulna and radius are about the same length and twisted around each other. The iliac bone is extremely stretched towards the head, the pelvic section in front of the acetabulum takes up twice the remaining pelvic length. There is a third rolling hillock on the thigh bone , which is usually only formed as a weak ripple. The fibula is connected to the shin at the base by ligaments .

The carpal and tarsal bones show a serial ( taxeopode ) arrangement, that is, the individual root bones of each row lie one behind the other and do not overlap one another. This directs the headbone at the wrist and the moonbone , at the tarsus the talus is only connected to the navicular bone and the heel bone only to the cuboid bone . The talus is firmly fixed by the two side ankles . Due to the special construction of the limbs, the hyrax are not able to rotate the hands and feet in the joint area, this is mainly done in the area between the root bones, with the hand also by rotating the shoulder joint. The hand has five rays (I to V), of which the thumb (ray I) is rudimentary and remains hidden under the skin. The outer ray (V) is also reduced in size. There are three rays on the foot (II to IV). The main axis of both the hand and the foot runs through the third ray, creating a mesaxonic structure.

Glands and tactile hair

The fur of the mountain forest tree slipper ( Dendrohyrax validus ) with a visible light spot

The back gland of the hyrax is a rather unusual formation, which is surrounded by a strikingly colored patch of hair as a bare skin surface. The gland is about 1.5 cm long and consists of seven or eight lobules of glandular tissue that sit deep in the skin. Each individual lobule contains 25 to 40 compartments, which are filled with epithelium containing secretions , which in turn surrounds an irregularly shaped cavity. From here, well-developed channels lead to the surface. The lobules swell, especially in sexually active animals, regardless of gender. The hairs of the colored patch around the gland usually lie flat like the rest of the fur and cover the gland. However, they can be straightened up when excited and then form a conspicuous tuft that exposes the gland.

Other glands are found on the soles of the hands and feet. The hyrax do not walk on the hooves, but on the bare sole, which is covered by an approximately 1 cm thick epithelial layer. Inside there are glands that penetrate the skin layer in high density with about 300 gland channels per square centimeter. The individual glands have a diameter of around 15 to 45 μm and are surrounded by fat and connective tissue . In principle, the glands are similar to those of primates , the cells are light or dark in color. The latter represent the actual secretion producers and contain the Golgi apparatus . They make glycoproteins . The secretions keep the soles of the hands and feet constantly moist. In conjunction with the muscular strength that the sole pulls in along the central callus crevice, the animals generate a high level of adhesive force , which enables them to climb trees and rocks or to walk over smooth, slippery and uneven surfaces.

A special feature of the hyrax is the distribution of the whiskers not only on the face, but regularly over the entire body. This feature occurs only rarely in other groups of mammals; it is known from manatees , for example . The individual whisker hairs are colored black and are longer than the rest of the hair. At the base, they show the structure typical for sensory sensitive hair with the hair follicle and the surrounding blood sinus , which are enclosed in a capsule made of connective tissue. The entire structure of the base is stretched compared to that of other hairs and interspersed with numerous nerves that end at the hair follicle. The skin around the capsule, in turn, is rich in blood vessels and enriched with fibrous tissue. The whiskers are used to orient the animals in narrow caves, rock chambers and passages.

Soft tissue anatomy

schematic representation of the digestive tract of a sleeper; d: duodenum; i: hip intestine; cm: cecum; c: additional appendix ("intestinal sac"); r: rectum; not to scale

The digestive tract is relatively complex, but not as strong as some groups of cloven-hoofed animals . The stomach has two chambers and is thus divided into two functional parts. The front section has no glands and acts primarily as a reservoir of food. The rear section with the gastric gatekeeper , on the other hand, is rich in glands. The adjoining small intestine is up to 130 cm long and ends in the appendix . This has an unusual structure, as it consists of a front, undivided chamber and a rear sack-like structure (also called "intestinal sac") with two conical appendages; Both parts of the appendix are connected by a 11 to 20 cm long part of the intestine . The anterior appendix section serves as a fermentation space and produces a large amount of volatile fatty acids . In the rear bag-like chamber, the digestive residues are slowly mixed. The liver is very subdivided and there is no gallbladder .

Females have a paired (rock hyrax) or two-horned uterus (tree and bush hyrax). They usually have one to three pairs of teats . The number of tree snakes is generally lower and the position of the teats is variably distributed between the breast and groin area. The bush hyrax and the rock hyrax often have one pair in the chest and two in the groin. The male's testicles are hidden in the abdominal cavity. In sexually inactive animals they weigh between 1.0 and 1.65 g. The penis is structured differently in the individual species. The tree snails have a simple, slightly curved shape, the rock hyrax it is short, elliptical in shape and thickened slightly upwards, while the bush hyrax has an appendage with the opening of the urinary canal . The differing distance to the anus also proves to be striking: it is the shortest with the tree snails with an average of 1.7 to 2.5 cm and the longest with the bush hyrax with 8.0 cm. The hyrax lies in between with values ​​of 3.5 cm.

Hyrax have two muscle groups that run to the tip of the nose. They do not form larger tendons and are only well separated from one another in their front section. Both muscles move the nose, but this can only be done to a limited extent. The chewing apparatus of the hyrax is similar to that of the herbivorous ungulates . It shows a dominance of the masseter over the temporalis muscle complex , which is also indicated by the high position of the mandibular joint and the extensive angular process. However, in contrast to many herbivores, the temporalis muscle is relatively larger in the snakes. This goes hand in hand with a relatively short snout. The animals are therefore on the one hand capable of more complex chewing movements like the ungulates, but can also put more force into the front dentition area. The short crown process means that the mouth can be opened wide, for example to present the upper, sharp incisors.

distribution and habitat

The hyrax are largely endemic to Africa . An exception is the hyrax , which also occurs in the Middle East , especially in the Levant and on the Arabian Peninsula . Apart from this occurrence, both the rock hyrax and the bush hyrax live mainly in the eastern and southern parts of Africa. They often prefer rocky, arid areas, but can also be found in savannah and forest landscapes in which stony areas or various rock formations are available. Both types occur partly sympatric . The tree hyrax, on the other hand, is largely restricted to forests. Their distribution ranges from western to central to eastern Africa and spreads from here to the southern part of the continent. The different species can be observed in the lowlands as well as in the mountains up to sometimes at altitudes of 4500 m. The presence and frequency of sleepers in a given region is influenced by external conditions. Abiotic factors include, for example, temperature and precipitation as well as the frequency of caves and loopholes as hiding places. Biotic factors relate to the frequency of predators or parasites , but also to intra- and inter-species competition for food resources.

Way of life

Territorial behavior

Bush sleeper family group

Family group of Klippschliefern in front of the cave entrance

Steppe forest tree hyrax ( Dendrohyrax arboreus ) sitting in the branches

In terms of behavior, there are strong differences between the rock hyrax and the bush hyrax on the one hand and the tree snails on the other hand, whereby the way of life in the former two has been well studied. The tree hyrax live tree-climbing ( arboreal ), they are nocturnal, solitary and retreat into tree hollows. Above all, trees are used, which offer several options for hiding. Occasionally, two to three individuals appear together, which are mother-young groups. The adult animals are territorial. The territories of the males overlap with those of several females and are defended against rivals. In contrast, both the rock hyrax and the bush hyrax form larger family groups or colonies; they are active during the day and live on the ground. Like the tree hyrax, the animals can climb well due to their foot anatomy and move quickly on uneven terrain. They are also able to climb trees. The individual groups inhabit rocky landscapes, which must be criss-crossed by numerous rock crevices and cavities. These serve as hiding places or retreats. A colony consists of a dominant male and related females and their offspring. The members of a colony use a more or less clearly defined territory that is defended by the male. In the savannah landscapes of eastern and southern Africa, such territories can comprise a single kopje . Larger Kopjes and more extensive rocky landscapes are inhabited by several family groups. Solitary males or hikers can also appear here. These are often young adult animals that have not yet formed their own group. Sometimes the rock hyrax and the bush hyrax appear sympatric and - depending on the season - form mixed groups during the day.

Energy balance and daily rhythm

The tree hollows of the tree hyrax and the crevices of the rock and bush sleeper not only offer protection from predators , but also create more balanced environmental conditions with more stable temperature and humidity conditions. The body temperature of the hyrax is 35 to 37 ° C. But it fluctuates with the outside temperature. The adaptation of the body temperature to the outside temperature takes place through acclimatization and does not follow a given daily rhythm. At higher ambient temperatures, usually above 25 ° C, thermoregulation takes place via perspiration at the nostrils and on the soles of the feet as well as via panting and increased salivation. The animals usually encounter low temperatures with an increased supply of oxygen . In addition, the hyrax have a low metabolism , which is about 30% below the value that would be expected for an animal of the same size. Both the unstable body temperature and the low metabolism contribute to energy savings. The kidneys are very efficient and can strongly concentrate urine or electrolytes . This enables at least the rock hyrax and the bush hyrax to live in very dry areas without having to ingest much fluid.

The labile body temperature largely determines the course of the day of the hyrax. The colony-forming species form in the early morning in groups with animals lying next to or on top of each other. The formations break up as soon as the sun warms the rocks. Then the animals mostly bathe in the sun in loose formation. In the hot hours of the day they retreat to the shade. An important part is the scratching and cleaning, which is done with the cleaning claw of the rear foot and with the lower incisors. Occasionally the animals also bathe in the sand and thus remove ectoparasites . Hyrax use latrines where they deposit their feces and urine. In the case of the colony-forming species, these are used jointly. The representatives of the tree hybrids climb down from the trees. Their latrines are often in easily visible places. The excrement interspersed with calcium carbonate forms an area-wide substance that is sometimes used as " hyraceum ".

Social communication

The intraspecific communication of the hyrax is diverse. In the interaction of different individuals, the respective position and posture play an important role. In general, head-to-head encounters are considered confrontational behavior. In social coexistence as well as in clusters during the cool times of the day, the heads of the animals are therefore always oriented outwards. Even when the family groups of the two colony-forming species eat or sunbathe together, the animals always have radial or opposite positions to one another. An open mouth and the presentation of the upper, long incisors can be viewed as aggressive behavior. The hair of the spot around the back gland, which can be straightened up when excited, serves as an important visual signal generator. The angle at which the hair rises provides information about the intensity of an animal's arousal. The patch of color has an important function, especially during the mating season and during the dominance struggles of the males. The secretions of the back gland are also used for odor detection , for example between mother and young animals. Other olfactory characteristics are used by males who, especially during the reproductive phase, search the latrines for smells from receptive females. What is striking, however, is that the hyraxes hardly give off scent marks to identify their territories.

The sound of the hyrax is very varied and consists of numerous calls that are produced in a wide variety of situations. The calls express the most varied of feelings such as aggression, threat, pacification or withdrawal. Of great importance are the calls of the males, which are referred to as "territorial" or "great call". They usually sound throughout the year at fixed times of the day, but can increase sharply during the mating season. Often the males animate each other during a calling period so that the sounds are carried far. They consist of a sequence of alternating call elements that increase in intensity towards the end. The entire series is repeated several times. Some of them are highly individualized, and differences in local populations can also be identified. For the hyrax it was determined that individual animals convey individual information about their physical characteristics or their social status with their calls.

nutrition

Bush hyrax climbing in the branches

All hyrax are pure herbivores. Their main food consists of soft parts of plants such as leaves , twigs , fruits and bark . There are clear local differences in the preferred plants, which are probably due to the availability for the individual populations . The rock hyrax and the bush hyrax also consume larger amounts of grass . The proportion can rise sharply, especially in the rainy season, but it is significantly higher for rock hyrax than for bush hyrax. Both types are equipped with higher tooth crowns on the molars because of the greater abrasion caused by the hard grass. The different diets of the two representatives of the slavery could also be documented by means of isotope analyzes and traces of abrasion. Water to drink is not a requirement as the animals can often draw enough liquid from their food.

The food is consumed with the teeth, the front feet are not used. The grinding of the food in the mouth takes place with lateral chewing movements. The food ingested passes through the body in a period of about four to five days, which is extremely long. The gastrointestinal tract is also able to digest fibrous plant material. Contrary to some older and more recent observations (including a mention in the Old Testament ), the animals do not chew their food again. Hyrax's stomach is simpler than that of ruminants . Possibly it is a misinterpretation of a stressful act in which individual individuals react to factors unknown to them with grinding chewing movements, but do not chop up any food. This is now known as "grinding your teeth" and can last for up to half an hour.

Reproduction

two cubs of the Klippschliefers riding on old animals

Reproduction has only been adequately studied in the rock hyrax and bush hyrax. The mating takes place once a year and is seasonally dependent, the sexual cycle of the females is repeated within several weeks. In the two colony-forming species, the mating season of the females in a family group is synchronized with one another. Year-round reproduction is also assumed for the tree hyrax. During the mating season , the males call out loudly and search the latrines for the smells of females ready to mate. Your testicles can swell a lot, sometimes 10 to 20 times their normal weight. Animals ready to mate perform a mating dance, which consists of chasing each other, rubbing against each other and presenting the trunk. Before the sexual act , the male usually lets out a shrill call. The male can step on the female several times within a few hours. So far only a few pairings have been observed, as these mostly take place in hiding places.

The gestation period for the sleepers is extremely long and lasts between 26 and 32 weeks. The tree hyrax give birth to one to two young per litter, with the rock hyrax and bush hyrax it is one to four. The number depends on the weight and age of the mother, young females often give birth to fewer offspring. Like mating, the females of a colony also give birth synchronously. The young are born well developed, they are fully hairy, have open eyes and can already walk and climb. The birth weight of the boys varies between 180 and 380 g. The young of the colony-forming species often form playgroups. They have a distinctive play behavior that consists of biting, climbing, pushing or chasing one another. Weaning takes place after five to seven months, and sexual maturity occurs between the 16th and 30th month. With the rock hyrax and bush hyrax, the young females are integrated into the colony, the young males leave the local family group and start their own. Life expectancy can be up to 14 years.

Predators

Because of their small size, hyraxes are hunted by numerous animals, including snakes , birds of prey and predators . Above all, the clip and the yellow-spotted rock hyrax are the main prey of the Black Eagle , to which there is also an ecological relationship due to the amount prey. Among the mammals, the leopard deserves special mention.

Systematics

External system

Internal systematics of Afrotheria according to Kuntner et al. 2011  Afrotheria     Paenungulata     Sirenia (manatees)   Dugongidae (Dugongs)      Trichechidae (manatees)       Hyracoidea (hyrax)      Proboscidea ( proboscidea )   Afroinsectiphilia    Tubulidentata (aardvark)   Afroinsectivora    Macroscelidea (elephant)   Afrosoricida    Chrysochloridae (golden mole)      Tenrecomorpha (tenreks and otter shrews )

The Hyracoidea form an order within the superordinate order of Afrotheria . The Afrotheria in turn represent one of the four main lines of the higher mammals and include various groups whose area of ​​origin is more or less on the African continent or who are among its original inhabitants. The togetherness of the Afrotheria is mainly based on molecular genetic studies, less on anatomical similarities. Within the Afrotheria, a distinction is made between two large groups: the Paenungulata and the Afroinsectiphilia . In the latter are the elephants and the tenre karts , and sometimes the aardvark is one of them. As a rule, the hyrax are related to the proboscis and manatees , all three of which in turn form the paenungulata. While the close relationship between sleepers, elephants and sirens is hardly doubted today and can be proven both genetically and morphologically and anatomically, the direct relationships between the groups are under discussion. On the one hand, the hyrax can be regarded as the sister group of the other two lines. In this case the elephants and manatees are incorporated into the common supergroup of the Tethytheria . On the other hand, the hyraxes face the elephants, while the manatees take the position of the outer group. A third constellation is a closer bond between the hyrax and the manatee, with the elephants as sister taxons to both. According to molecular genetic studies, the origin of the Afrotheria is in the Upper Cretaceous between 90.4 and 80.9 million years ago. Around 15 million years later, this group of origins split into the two main lines of today. The hyrax differentiated in the Paleocene about 60 million years ago, which roughly agrees with the fossil record . But the ancestors of today's hyrax represent a relatively young line of development that only appeared in the Lower Miocene around 20 million years ago.

Internal system

Internal systematics of the recent hyrax according to Maswanganye et al. 2017   Procaviidae    Procavia      Heterohyrax      Dendrohyrax

The order of the Hyracoidea is composed recently only from the family of the Procaviidae and is therefore monotypical . In addition to the animals' characteristic external appearance, special features can be found in the reduced set of teeth and in individual special tooth features. As a rule, three genera are differentiated within the Procaviidae with the rock hyrax as the nominate form , the bush hyrax and the tree snails . They differ anatomically, among other things, in the number of teeth, the height of the crowns of the molars or in the shape or lack of a postorbital arch or a crest. There are also differences in lifestyle. The first two genera contain only one species each, the last a total of three. The exact number of species is controversial; in general, today's hyraxes are viewed as taxonomically too strongly summarized. There is also the possibility that individual species still live hidden and have not yet been described.

Fossil are recognized at least five other families. The Geniohyidae are composed of largely original, small forms with an elongated skull and teeth that are not very specialized. The closely related Namahyracidae are characterized by very low-crowned teeth with voluminous cusps on the chewing surface of the molars. The Titanohyracidae , which appeared almost at the same time, were, in contrast, more specialized with simple ridges on the molars. They also produced the first giant hyraxes. The Saghatheriidae in turn comprised predominantly smaller members, which already had significant length reductions in the skull. Within the Saghatheriidae there is possibly the group of origin for the development of the Procaviidae and also the Pliohyracidae . The latter are characterized by strongly high-crowned molars, as well as by a massive increase in body size during the tribal history. The six families are sometimes divided into two different suborders, with the Geniohyidae, Namahyracidae and Titanohyracidae then within the Pseudhippomorpha , the others within the Procaviamorpha . The two higher-ranking groups within the hyrax go back to Thomas Whitworth from 1954, who separated the long-snouted early forms from the short-snouted later forms. Whitworth chose the name Pseudhippomorpha because the upper rear teeth of the older hybrids reminded him of those of the original horses , while the Procaviamorpha have teeth comparable to the rhinos .

Sometimes all non-procavoid hyraxes are kept within one family, the Pliohyracidae. In this classification system, the other families then have the status of a subfamily. This scheme has been criticized several times because the range of variation of the extinct forms is much greater than that of those living today. The forms of the Middle and Upper Miocene are also much closer to today's slivers than to the early forms of the Eocene and Oligocene .

Overview of the families and genera of hyrax

The order of the hyrax is divided into five families with more than two dozen genera, three of which are recent. The structure presented here is based on Martin Pickford et al. 1997 and D. Tab Rasmussen et al. 2010, also takes into account more recent developments:

• Order: Hyracoidea Huxley , 1869

• Subordination: Pseudhippomorpha Whitworth , 1954

• Rukwalorax Stevens, O'Connor, Roberts & Gottfried , 2009

• Family: Namahyracidae Pickford , 2015

• Dimaitherium Barrow, Seiffert & Simons , 2010
• Namahyrax Pickford, Senut, Morales, Mein & Sanchez , 2008
• Seggeurius Crochet , 1986

• Family: Geniohyidae Andrews , 1906

• Geniohyus Andrews , 1904
• Bunohyrax locksmith , 1910
• Pachyhyrax locksmith , 1910
• Brachyhyrax Pickford , 2004

• Family: Titanohyracidae Matsumoto , 1926

• Titanohyrax Matsumoto , 1921
• Antilohyrax Rasmussen & Simons , 2000
• Afrohyrax Pickford , 2004
• Rupestrohyrax Pickford , 2015

• Suborder: Procaviamorpha Whitworth , 1954

• Family: Saghatheriidae Andrews , 1906

• Microhyrax Sudre , 1979
• Saghatherium Andrews & Beadnell , 1902
• Selenohyrax Rasmussen & Simons , 1988
• Thyrohyrax Meyer , 1973
• Megalohyrax Andrews , 1903
• Regubahyrax Pickford , 2009

• Family: Pliohyracidae Osborn , 1899

• Meroëhyrax Whitworth , 1954
• Prohyrax Stromer , 1924
• Parapliohyrax Lavocat , 1961
• Pliohyrax Osborn , 1899
• Kvabelihyrax Gabunia & Vekua , 1966
• Hengduanshanhyrax Chen , 2003
• Sogdohyrax Dubrovo , 1978
• Postschizotherium von Koenigswald , 1932

• Family: Procaviidae Thomas , 1892

• Heterohyrax Gray , 1868 (Bush hyrax, including a recent species)
• Dendrohyrax Gray , 1868 (tree hyrax, including three recent species)
• Procavia Storr , 1780 (rock hyrax, including a recent species)
• Gigantohyrax Kitching , 1965

Research history

Taxonomy

Gottlieb Conrad Christian Storr

Oldfield Thomas

Thomas Huxley

Research into hyrax dates back to the late 18th century. The first scientific description of a Schliefers goes back to Peter Simon Pallas (1741-1811), who in 1766 named the hyrax as Cavia capensis . The word cavy is actually of Caribbean origin and describes the guinea pigs , whose main distribution area is in South America . The rather unusual naming for an African animal prompted Gottlieb Conrad Christian Storr (1749-1821) to replace the generic name with Procavia in 1780 . Only three years later, Johann Hermann (1738–1800) created the genus Hyrax for the hyrax . Hyrax, in turn, is borrowed from the Greek ( ξραξ hýrax ) and means "shrew". The word spread quickly and was used widely in the years that followed. Usually it was applied to all hyraxes. The other generic names Heterohyrax for the bush hyrax and Dendrohyrax for the tree hyrax, both of which come from John Edward Gray (1800–1875) in 1868, are based on it. The family name Hyracidae also goes back to Hyrax , also introduced by Gray in 1821. He defined the hyrax as follows: nose and ears short; toes four in front, three behind; hoofs small, round, except the inner-hinder toes, which have an arched claw; teeth cutting, two above, four below; canine, two below, two above, when young; stomach two-lobed, caecum large. ("Nose and ears short; four toes in front, three in back; hooves small, round, with the exception of the inner rear ones, which have curved claws; incisors, two above, four below; canine, two below, two above; stomach with two chambers , Large appendix "). Thomas Huxley (1825–1895) then created the name Hyracoidea in 1869 for the order of the hyrax. Huxley used a definition that was very similar to Gray's. At that time the order contained Hyrax as the only genus. Fernand Lataste first pointed out in 1886 that the generic name Procavia had been introduced three years before Hyrax . In the following, Oldfield Thomas (1858-1929) continued this in 1892 and once again emphasized the priority of Procavia over Hyrax . He then suggested the family name Procaviidae, as this, in contrast to Hyracidae, was based on a valid generic name. Thomas kept the order Hyracoidea, as no recognized genus is necessary as a name basis for this.

The discovery of the fossil hyrax

Lower jaw from Pikermi, published by Albert Gaudry in 1867 as the first fossil record of a sliver and assigned to the genus Leptodon

Although hybrids have been known to science since at least the second half of the 18th century, fossil forms were discovered relatively late. Early research finds are documented from Greece . These were discovered in Pikermi in the Attica region since the second half of the 19th century. Albert Gaudry published the first extensive fossil catalog of the deposit in 1867 and presented two lower jaws, which he assigned to the genus Leptodon . Their relationships were not known at the time, but Gaudry suspected a close connection to the rhinos . More than 30 years later, Henry Fairfield Osborn presented the facial skull of a sleeper, from the Greek island of Samos , which was in the collection of the Krupp family . Osborn recognized that it belonged to the Schliefern and created the new genus Pliohyrax for the find . In the same year, Max Schlosser proved that the remains of both Pikermi and Samos represent the same genus ( Leptodon as a genus name is, however, preoccupied by a representative of the birds of prey, which is why the finds are now listed under Pliohyrax ). With a dating to the Upper Miocene, they were the oldest known evidence of slivers at the time.

Almost at the same time, finds of slates came to light in the Fayyum in northern Egypt , but with an age from the Upper Eocene to the Lower Oligocene, they are significantly older. Here Hugh John Llewellyn Beadnell was active as a geologist and collected fossils since the end of the 19th century. As early as 1902 he and Charles William Andrews presented the skull of a sleeper, which they named Saghatherium . In the winter of the same year, Beadnell discovered a remains of the upper jaw and a lower jaw of other hyraxes. Both were subsequently described by Andrews. The former he named Megalohyrax because of its size , for the latter he created the genus Geniohyus . However, the bumpy tooth structure tempted Andres to group the shape with the pigs . The error was not recognized until 1911 by Max Schlosser when he was working on the Fayyum fossils from various collections in Germany. Above all, Schlosser's work and later, in 1926, that of Hikoshichiro Matsumoto produced a diverse hyrax community in the Fayyum that far surpassed that of today's representatives.

In the following time, fossil forms of hyrax came to light in other regions of Africa, for example in the 1920s in Namibia or in the 1930s in South Africa . The latter was the first evidence of extinct representatives of today's species. In Asia , too , the first evidence of lines of hyrax that no longer exist today was found at this time.

Hyrax in South America?

A controversy arose in the transition from the 19th to the 20th century with the view that the hyrax originally spread in South America . Already Theophil Noack had 1894 on the similarity of the Hyrax with the South American notoungulata pointed out. The Notoungulata is a very diverse, extinct group that is now generally considered to be the " South American ungulates ". In his writing, Noack referred to Florentino Ameghino , who five years earlier had presented an extensive collection of fossils from Argentina. Some of the skulls described reminded Noack of hyrax. Ameghino apparently shared this view and created the Archaeohyracidae family in 1897 , including Archaeohyrax . He saw the family as the forerunners of the hyraxes that, in his opinion, had developed in South America. Later he introduced genera such as Pseudhyrax or Eohyrax . Ameghino reaffirmed his position on the inclusion of the Archaeohyracidae in the hyrax in 1906 in an overview work on the history of the South American fauna.

Numerous researchers at that time were critical of this interpretation. As early as 1896, Richard Lydekker , in an answer to Noack's statements, referred to the differently constructed wrists in Schliefern and Notoungulata, the root bones of which are arranged serially in the former and alternately in the latter. He also produced paleogeographical arguments against such a kinship relationship. Max Schlosser initially spoke out in favor of this family relationship, but then criticized Ameghino in his processing of the fossils from the Fayyum in 1911 and turned against his view. The opinion that the Notoungulata and the hyrax are closely related is no longer shared today, even if individual researchers have identified certain anatomical similarities between the Afrotheria and the "South American ungulates". Molecular genetic studies make a closer relationship between the Notoungulata and the odd-toed ungulate more likely. From today's perspective, the Archaeohyracidae are a group of early representatives of the Notoungulata, largely restricted to the Eocene , which are characterized by a certain high crown of the teeth. For more traditional reasons, genera of the Archaeohyracidae with the addition of -hyrax are still introduced today , for example in 2008 with Punohyrax .

The systematic position of the hyrax - a research-historical debate

In the course of their research history, the hyraxes were assigned to different systematic relationships. Pallas and Storr considered them to be representatives of rodents in the second half of the 18th century. At this point in time, however, the view was not always shared. At the beginning of the 19th century, Johann Karl Wilhelm Illiger created a family of his own under the name Lamnunguia for the hyrax and translated it as “nail hoofs”, referring to the characteristic hoof formation. During the same period, Georges Cuvier described a skull of the Klippschliefers and recognized a closer relationship to other ungulates . Thereupon he assigned them (under the name Hyrax ) to the group of pachydermes (pachyderms) named by him, in which he referred, among other things, the trunk animals , rhinos , tapirs , hippos and peccaries . Cuvier saw the hyrax in a mediator role between the tapirs and rhinos. This presumed closer relationship was supported by the fact that the hyraxes have molars that are roughly similar to those of rhinos. After the concept of the "pachyderms" had not prevailed, Richard Owen included the hyrax in his first description of the odd ungulate in 1848, while Othniel Charles Marsh did not consider them in his conceptually similar Mesaxonia. The assumption of a closer relationship between the hyrax and the odd-toed ungulate remained until the 1980s. The hyraxes within the Perissodactyla were considered to be the sister group of the Mesaxonia, which the odd ungulates occupied in today's and traditional sense (rhinos, horses and tapirs).

Parallel to this assumption, a closer relationship to the proboscis and manatees was postulated, which was first mentioned in 1870 by Theodore Gill . However, Gill did not formulate a name for this relationship (previously in 1834 Henri Marie Ducrotay de Blainville had united the elephants and manatees under the term Gravigrades; in the 19th century, however, this name was more associated with the ground sloth). The inconclusive assignment of the Hyracoidea is also shown in Edward Drinker Cope's designation Taxeopoda from 1882, in which he grouped the hyrax due to their special foot skeleton together with the condylarthra , primeval ungulates that are now extinct, while William Henri Flower and Richard Lydekker grouped the Hyrax in the parent taxon Subungulata saw, together with the proboscis, the condylarthra, the so-called Amblypoda ( Pantodonta and Dinocerata ) and South American ungulates. Max Schlosser took up the idea of ​​the Subungulata in 1923 and, among them, united the manatees and the Embrithopoda in addition to the snipers and the trunk animals . In 1945, George Gaylord Simpson introduced the name Paenungulata , under which he combined the previous attempts at classification by Cope, Lydekker and Flower and above all Schlosser. The non-continuation of the Subungulata in the sense of Schlosser - the term had become very well established in the following years - was due to the fact that it had already been used by Illiger in 1811 for a group of rodents, especially the guinea pig relatives .

In the second half of the 20th century, the debate about the closer relationship of the hyrax with either the proboscis and manatees or with the odd-toed ungulates came up again. Various arguments were exchanged for this. Some researchers saw in the special taxeopod , that is, the serial arrangement of the carpal and tarsal bones, an indication of a closer relationship with both the condylar and the proboscis, in which this characteristic also occurs. Most other hoofed animals, however, have an alternating arrangement of the bones of the wrist and ankle ( diplarthral arrangement). However, other researchers saw the taxeopody of hyrax and proboscis as a convergent development and advocated a position near the odd ungulates. For this, among other things, the sac-like rear formation of the eustachian tube ( Eustachi tube ) of the middle ear should speak, which is a characteristic of both hyrax and odd-toed ungulates. Thus, the question could not be clarified unambiguously in a morphological-anatomical way, as arguments were available for both possibilities. As early as the early 1980s, innovative research approaches provided new insights into the kinship of hyraxes to other animal groups. Studies of structural proteins, for example, relegated the hyrax to the proximity of the manatees , elephants and aardvark . This could be confirmed with the help of molecular genetic analyzes at the end of the 1990s . This showed that the hyrax along with the elephants and sea cows and the aardvark and beyond with the tenrecs , the gold Mullen and the elephant-shrews form a unity based on genetic similarities that Afrotheria was called. Numerous other studies support this view so far.

Tribal history

Adaptive radiation

The hyrax are a very old order and have their origin in Africa. In the Paleogene , when Africa was an isolated island with no connection to other mainland masses, they occupied the niche of today's artifacts and odd-toed ungulates , which only immigrated in the Neogene about 23 million years ago. As a result, the hyrax, especially in the Palaeogene, showed an extremely high variety of shapes, ranging from small, rabbit-sized animals to those with the dimensions of a smaller rhinoceros. They were both adapted to a difficult gait, but also produced representatives that ran fast or jumped, just as some followed a tree-climbing way of life. In addition to the proboscis , which also come from Africa, the hyrax are one of the most important endemic groups on the continent. Three different phases of radiation can be distinguished within the tribal history of the hyrax . The first includes the earliest forms of the paleogene with the families of Namahyracidae , Geniohyidae , Saghatheriidae and Titanohyracidae , which achieved high ecological and morphological diversity. These formed a key element in the early tertiary mammalian communities in Africa and are also considered to be important indicators for biostratigraphy . The second radiation phase is limited to the Pliohyracidae, which have particularly high-crowned teeth, and began in the late Oligocene . It provided the basis for the later Eurasian hyrax forms, which can be detected for the first time in the Miocene and which later reached enormous body sizes. In the Upper Miocene, the third, far less effective radiation phase took place. These passed through the Procaviidae, which still exist today, whose representatives nested in marginal ecological niches due to the increasing and strong competitive pressure caused by the Eurasian ungulates now dominating in Africa. As a result, these modern hyraxes of the once richly shaped hyracoids could survive to the present day.

Eocene

The earliest confirmed occurrence of hyrax dates back to the transition from the Lower to the Middle Eocene around 50 million years ago. The finds of El Kohol on the southern edge of the Atlas in Algeria are significant here . These are mainly lower jaw remains and isolated teeth, which are assigned to the genus Seggeurius from the family of Geniohyidae. The bunodonte (bumpy) chewing surface pattern of the molars was characteristic, which classifies the genus as very primitive within the hyrax. It is probably a representative of the Namahyracidae. An isolated posterior molar from the Ouled Abdoun Basin in Morocco , which belongs to the Lower Eocene and possibly also comes from Seggeurius , could be even older . The finds from Chambi in Tunisia are just as old as El Kohol. In addition to some smaller hybrids, they also produced a first representative of the Titanohyracidae with Titanohyrax ; but the representative did not yet reach the enormous proportions of his later relatives. Bunohyrax appears still in the transition from the Middle to the Upper Eocene , handed down on the basis of some teeth from Bir el-Ater in Algeria, which belongs to the more primitive forms with simply designed chewing surface patterns on the molars and is therefore more closely related to Seggeurius . Dimaitherium , a small hyrax from the Qasr-el-Sagha Formation , which may have been an agile climber, comes from the extremely fossil-rich and important Fayyum in Egypt . Its age is estimated to be around 37 million years. After initially unclear relationships, the genus has been part of the Namahyracidae family since 2015. The Gebel Qatrani formation of the Fayyum is of outstanding importance. It generally dates between 34 and 28 million years ago, which means that the lower sections are still in the late Eocene. Antilohyrax , a representative of the Titanohyracidae, has a singular appearance in this period . Several complete skulls were recovered from him. Other important genera have their first record in this lower section of the formation, such as Saghatherium or Thyrohyrax , both from the Saghatheriidae group.

Aside from all these North African sites, Namahyrax from the restricted area of Namibia has been identified as early as the Middle Eocene via a fragment of the fore skull that had extremely low-crowned teeth and was probably closely related to Dimaitherium and Seggeurius . An additional lower jaw that was also found stands out due to its elongated symphysis , which clearly separated the front teeth from the molars. Namahyrax probably had sensitive and flexible lips, which suggests a special diet. In the same region, the only slightly younger, but significantly larger Rupestrohyrax could be described on the basis of a skull, but that it is related to the Titanohyrax .

Lower jaw of Saghatherium

Overall, these early hyrax of the Eocene appear very diverse with the most varied of adaptation phenomena. Above all, the structure of the molars, which are one of the most common fossil remains of the early hyrax, shows a wide variety of food preferences and thus an adaptation to different ways of life. The archaic Geniohyidae and Namahyracidae with their bunodont chewing surface pattern followed an omnivorous diet similar to today's pigs . In contrast, the saghatheriids and titanohyracid hyraxes with two transverse melting strips ( bilophodont ) on the chewing surfaces show stronger specializations. According to this, the gigantic Titanohyrax was a strict leaf eater. The much smaller Antilohyrax preferred generally soft vegetable food, recognizable by the selenodontic superstructure of the teeth, which is reminiscent of the chewing surface pattern of today's ruminants . According to its musculoskeletal system, Antilohyrax was very fast-moving and probably also capable of jumping. Saghatherium, on the other hand, also devoured harder plant foods such as seeds and nuts due to its massive lower jaw. Thyrohyrax was a very small representative of the early hyracoids and weighed around 6.5 kg, so it is in the range of variation of today's hyrax. He represented an agile climber, his skull structure and the design of the teeth are strikingly reminiscent of today's tree hybrids , which have a longer snout and lower-crowned teeth compared to the other recent forms. Thyrohyrax possibly belongs to a larger group of origins of small hyracoids from which the later procavoid hyraxes arose. In numerous early snakes such as Thyrohyrax and Saghatherium , an anatomical peculiarity occurs in the form of chamber-like cavities in the lower jaw, which is not documented in today's snakes. The function of the chambers is being discussed, possibly related to the vocalization. Since the chambers are apparently only developed in males, they may express a sexual dimorphism .

Oligocene

Titanohyrax tooth remnants

The hyrax attained a great diversity in the Oligocene with more than a dozen proven genera from four families. The richness is mainly reflected in the Gebel Qatrani formation in the Fayyum Basin. The forms known from the lower sequences of rock formation such as Bunohyrax , Saghatherium or Thyrohyrax appear, Pachyhyrax , a presumably semi-aquatic hyrax , or Megalohyrax , a large form weighing 160 kg and 39 cm long skull appear. Titanohyrax surpassed all other hyraxes in body size at that time and reached a weight of 800 to 1000 kg, but is generally rarely documented. So far unique are the finds of an almost completely articulated skeleton and several other partial skeletons that came to light in Gebel al Hasawnah in Libya ; they are considered to be the only ones of a palaeogenic sleeper to date. The skeletons represent Saghatherium and for the first time allowed the complete reconstruction of a small, extinct hyracoid, whose body structure was clearly similar to that of today's forms. This enabled the taxeopode arrangement of the root bones to be fully documented for the first time in the early sleepers on the basis of the foot structure. However, there are also striking differences: The early hyraxes obviously had claws, the hoof-like nails of today's species thus probably represent later formations. In addition, the early hyraxes moved as toe walkers , deviating from the sole passage of the recent relatives. From a paleobiographical point of view, the Lower Oligocene finds from Malembe in Angola , which contain individual teeth of Geniohyus and Bunohyrax , are to be emphasized . The first records of slivers on the Arabian Peninsula , which at that time still formed a unit with Africa , date back to around 33 million years . For example, remains of Saghatherium and Thyrohyrax have been recovered from Taqah and Thaytiniti in Oman .

In the following period, hyraxes have been handed down in moderate diversity in Chilga in Ethiopia , which dates back to around 27 million years. Among the mostly fragmented bone material, older forms such as pachyhyrax , bunohyrax and megalohyrax predominate . In the further course of the Oligocene only a few fossil sites from Africa are known. The Lothidok site in northwestern Kenya , which dates back to a period of 27 to 24 million years, is significant here . Here, too, older forms of the Geniohyidae are represented by Brachyhyrax , the Saghatheriidae are represented by Thyrohyrax and the Titanohyracidae by Afrohyrax . As one of the earliest representatives of the Pliohyracidae, Meroëhyrax also appears , whose finds include numerous lower jaw fragments. He already has more high-crowned molars, which is typical of the Pliohyracidae, but does not occur in the earlier lines. Evidence of Rukwalorax comes from the Nsungwe formation in Tanzania , which can be dated to around 25 million years ago . However, so far there is only one lower, inner incisor, which is characteristic and, similar to numerous other slivers, also characterized by several high pegs standing side by side, so that the tooth crown appears to be fanned out like a comb. With its higher number of pins, the tooth in the overall habitus is somewhat reminiscent of that of the older antilohyrax .

Miocene

Skull of Afrohyrax

Initially, even older lines appeared, such as Brachyhyrax and Afrohyrax in Kenya and Uganda , but the latter was much more widespread and has also been found on the Arabian Peninsula and in southern Africa. In the earliest Middle Miocene, Regubahyrax appears , a leaf-eating representative of the Saghatheriidae, which was described using several fragments of the lower jaw from Libya. In the Miocene , however, there was the rise of the Pliohyracidae, a highly specialized group with high-crowned teeth that emerged from saghatheriiden slivers. The small Meroëhyrax , already known from the Oligocene , also occurs in the Lower Miocene of East Africa. From the late Lower and early Middle Miocene, further forms of the Pliohyracidae have been found in Africa. This includes the small, only 4.5 kg heavy Prohyrax , of which numerous finds came to light in southern Africa, including upper and lower jaw fragments in Vallunga, Elisabethfeld and Arrisdrift in Namibia , of which Prohyrax accounts for more than 40% of all fossil finds. Some also come from East Africa. Parapliohyrax , which at around 90 kg was already significantly larger than its predecessor, appears for the first time in the Middle Miocene and is documented with finds from eastern and northern Africa. At the beginning of the Upper Miocene, the Pliohyracidae died out again in Africa. The most recent find, an isolated tooth from an indeterminate representative from the Namurungule Formation of the Samburu Mountains in Kenya, is estimated to be around 9 million years old. The first evidence of procavid hyrax is about a million years older, with numerous finds of an adult individual and two young animals from the Otavi Mountains in Namibia. They represent extinct representatives of today's bush sliver . Finds from Lemudong'o in Kenya are assigned to the tree hyrax, which are placed at the end of the Miocene about 6.1 million years ago.

Skull of Pliohyrax

The closing of the Tethys Ocean and the creation of a land bridge to Eurasia made it possible for the snakes to leave Africa, similar to the proboscis, but only representatives of the Pliohyracidae managed to do so. The oldest clear evidence of a hyracoid outside of Africa (and the connected Arabian Peninsula) is known from the sub-Miocene Pandánassa formation near Mélambes on Crete in Greece. This involves a damaged lower jaw and a calcaneus , but it is unclear whether the findings are related to Pliohyrax or Prohyrax . Pliohyrax is considered a descendant of Parapliohyrax and was widespread in western Eurasia, most of the finds date to the Upper Miocene. Significant fossils come from Casablanca and Can Llobateres in Spain , but they mostly include isolated teeth and occasional postcranial skeletal material. Further finds were discovered in France , from the eastern Mediterranean the finds from Pikermi and Samos (both Greece ) and from various sites in Turkey should be emphasized. One lower jaw, in turn, comes from Maragheh in Iran . In contrast to the Pliohyraciden of Africa, the forms in Eurasia reached a fairly high variety. In the course of their development they increased in body size and developed extremely high-crowned teeth. The increase in the crown height of the molars suggests that the hyrax of that time consumed a higher proportion of grass.

Pliocene and Pleistocene

In the Pliocene and Pleistocene , Africa was populated exclusively by representatives of the Procaviidae. The Procaviidae differ from the other snakes in their reduced front dentition. Above all, fossil relatives of today's Klippschliefers are represented quite often, the oldest finds are from Langebaanweg in southwest Africa and belong to the beginning of the Pliocene around 5 million years ago. Most of the other fossils are also largely restricted to southern Africa, including some from important sites such as Swartkrans , Sterkfontein or Makapansgat . In addition to the three genera that still exist today, Gigantohyrax also occurs in southern and eastern Africa in the Pliocene , but in contrast to its name it was only slightly larger than today's hyrax.

In contrast to the relatively small procaviids in Africa, the Pliohyracidae developed gigantic forms in Eurasia. However, they had largely left the European regions again after the end of the Miocene. From the Pliocene of today's Georgia is close to Pliohyrax related Kvabebihyrax narrated that kg weighed about 350 and suggests a semi-aquatic lifestyle with diet of aquatic plants whose design of the snout. At around 3 million years old, it is the youngest find in western Eurasia. Sogdohyrax from Tajikistan is similarly old and also closely related, but only a fragmented skull was found. The representatives of the genus reached a weight of up to 820 kg. Based on the tooth morphology, it is partly assumed that the genus is synonymous with Pliohyrax . A partial skull of Hengduanshanhyrax from the Wangbuding Formation in the Chinese province of Sichuan also dates to the end of the Pliocene . The easternmost and northernmost distribution of all hyracoids is shown by Postschizotherium , which was originally considered a member of the Chalicotheriidae from the group of odd ungulates . The genus was also the largest representative of the Pliohyracidae with a weight of about 1170 kg. A so far unique find comes from Udunga west of Lake Baikal , which is the only find region for Eurasian hyracoids north of the 45th parallel . Most of the fossil material has so far been reported from China . The most recent finds include five partial skulls and associated mandibular fragments from the Tianzhen Basin in Shanxi Province , which belong to the Old Pleistocene . Apparently the Pliohyracidae became extinct in the Old Pleistocene, as more recent finds are not yet known. Overall, however, the fossil record of the Pliohyracidae in Eurasia is so far too patchy to obtain a more precise history of the group's distribution.

etymology

Hyrax have been known in Palestine for thousands of years and are mentioned four times in the Bible. The Hebrew word שפן ( shaphan ) for the rock hyrax means something like "the one who hides" and refers to his way of life in rock crevices. Hyrax were unknown in most regions of Europe, which is why the various Bible translations usually compared the shaphan with regionally familiar animals such as the rabbit, the hedgehog or the groundhog. In his complete translation of the Bible in 1534, Martin Luther translated the shaphan with “rabbit”; it was not until the revision of the Luther Bible of 1912 that the incorrect interpretation was replaced by the term “ rock badger ”.

The German trivial name "Sch Liefer" comes from the word slept for "crawl" or "slide around". It was used as early as 1792 by Johann Christian von Schreber in his work Die Säugthiere in images from nature with descriptions . In English, the colloquial term hyrax is common, which is derived from Johann Hermann's generic name Hyrax . In contrast, in southern Africa the word dassie refers to a hyrax . The name was coined by the Boer colonists of South Africa , it goes back to the Dutch word that means "badger" ( that they accordingly "badger"). The French language, on the other hand, knows the word daman . This goes back to the Israel of the English cleric and traveler Thomas Shaw, who used the term in 1738. Shaw referred again to Prospero Alpini , who at the end of the 16th century mentioned the hyrax of Egypt as agnus filiorum Israel ("Lamb of the Children of Israel"). The daman Israel can possibly be traced back to a misunderstanding, since in Arabic the hyraxes are named with ganamn banî israîl (“cattle of the children of Israel”) or rhanem israel (“sheep of the Israelites”).

The equation of rabbits and hyrax is not limited to the Bible: According to a common hypothesis, the Phoenicians held around 1000 BC. Rabbits for hyraxes were sighted on the Iberian Peninsula and given the name I-Shapan-im ("land of hyrax"). The Romans later converted this to the Latin name Hispania . The eponymous animals had long since died out there.

Threat and protection

The hyrax are mainly hunted for their meat and fur. This can lead to significant declines in local stocks. For the tree hyrax the deforestation of the forests and the fragmentation of the landscape are a threat. The rock hyrax is sometimes considered a pest in some regions. The IUCN currently (2018) only lists the mountain forest tree hybrids in the early warning level "potentially endangered" ( near threatened ), the other species are not considered to be endangered by the environmental protection organization. All hyrax representatives are present in nature reserves. In some cases, however, investigations into the actual distribution of the animals are necessary.

literature

• Robert M. Eley: The hyrax: a most mysterious mammal. Biologist 41 (4), 1994, pp. 141-144
• Herbert Hahn: About tree, bush and rock slippers, the little relatives of the manatees and elephants. Wittenberg, 1959, ISBN 3-7403-0193-7
• Angela Gaylard: Procavia capensis (Pallas, 1766) - Rock hyrax. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 41-50
• Hendrik Hoeck: Family Procaviidae (Hyraxes). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, pp. 28-47 ISBN 978-84-96553-77-4
• Ronald M. Nowak: Walker's Mammals of the World. Johns Hopkins University Press, 1999, ISBN 0-8018-5789-9
• Jeheskel Shoshani, Paulette Bloomer and Erik R. Seiffert (including other authors): Order Hyracoidea - Hyraxes. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London, 2013, pp. 148-171

Individual evidence

1. ^ RP Millar: An unusual light shielding structure in the eyes of the dassie (Procavia capensis Pallas) (Mammalia: Hyracoidea). Annals of the Transvaal Museum 28 (11), 1973, pp. 203-205
2. ↑ George Lindsay Johnson: Contributions to the comparative anatomy of the mammalian eye, chiefly based on opthalmoscopic examination. Philosophical Transaction of the Royal Society (B) 194, 1901, pp. 1–82 ( [1] )
3. ↑ ^{a b c d e f g h} Angela Gaylard: Procavia capensis (Pallas, 1766) - Rock hyrax. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 41-50
4. ↑ ^{a b c d e f g h i j k} Hendrik Hoeck: Family Procaviidae (Hyraxes). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, pp. 28-47 ISBN 978-84-96553-77-4
5. ↑ ^{a b c d e f g h i j k l m n o p} Jeheskel Shoshani, Paulette Bloomer and Erik R. Seiffert (including other authors): Order Hyracoidea - Hyraxes. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London, 2013, pp. 148-171
6. ↑ ^{a b} Herbert Hahn: The family of the Procaviidae. Journal of mammalian science 9, 1934, pp. 207–358 ( [2] )
7. ^ ^{A b c} Grant E. Meyer: Hyracoidea. In: Vincent J. Maglio and HBS Cooke (Eds.): Evolution of African Mammals. Harvard University Press, 1978, pp. 284-314
8. ^ ^{A b} Christine M. Janis: Muscles of the Masticatory Apparatus in Two Genera of Hyraces (Procavia and Heterohyrax). Journal of Morphology 176, 1983, pp. 61-87
9. ^ Henry Fairfield Osborn: Evolution of mammalian molar teeth to and from the triangular type. New York, 1907 pp. 1–250 (pp. 185–186) ( [3] )
10. ^ Robert J. Asher and Thomas Lehmann: Dental eruption in afrotherian mammals. BMC Biology 6, 2008, p. 14 doi: 10.1186 / 1741-7007-6-14
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133. ^ ^{A b} Martin Pickford: Revision of the Early Miocene Hyracoidea (Mammalia) of East Africa. Comptes Rendus Palevol 3, 2004, pp. 675-690
134. ↑ Hiroshi Tsujikawa and Martin Pickford: Additional specimens of Hyracoidea (Mammalia) from the Early and Middle Miocene of Kenya. Annales de Paléontologie 92, 2006, pp. 1-12
135. ↑ Martin Pickford and Brigitte Senut: Afrohyrax namibensis (Hyracoidea, Mammalia) from the Early Miocene of Elisabethfeld and Fiskus, Sperrgebiet, Namibia. Communications of the Geological Survey of Namibia 18, 2018, pp. 93–112
136. ↑ Martin Pickford: New specimens of Brachyhyrax aequatorialis (Geniohyidae) and Meroehyrax bateae (Pliohyracidae) from East Africa. Geo-Pal Uganda 8, 2013, pp. 1–8
137. ^ Martin Pickford: Middle Miocene Hyracoidea from the lower Orange River Valley, Namibia. Memoir of the Geological Survey of Namibia 19, 2003, pp. 199-203
138. ↑ Hiroshi Tsujikawa: The updated Late Miocene large mammal fauna from Samburu Hills, northern Kenya. African Study Monographs, Suppl. 32, 2005, pp. 1-50
139. ↑ D. Tab Rasmussen, Martin Pickford, Pierre Mein, Brigitte Senut and Glenn C. Conroy: Earliest Known Procaviid Hyracoid from the Late Miocene of Namibia. Journal of Mammalogy 77 (3), 1996, pp. 745-754
140. ↑ Martin Pickford and Leslea J. Hlusko: Late Miocene procaviid hyracoids (Hyracoidea: Dendohyrax) from Lemundon'o, Kenya. Kirtlandia 56, 2007, pp. 106-111
141. ^ Siegfrid E. Kuss: A first find of Pliohyrax from the Vallesium of Crete / Greece. New Yearbook for Geology and Paleontology, Monthly 3, 1976, pp. 157–162
142. ↑ Martin Pickford: Fossil hyraxes (Hyracoidea: Mammalia) from the Late Miocene and Plio-Pleistocene of Africa, and the phylogeny of the Procaviidae. Palaeontologia Africana 41, 2005, pp. 141-161
143. ^ IA Dobrovo: New data on fossil Hyracoidea. Палеонтологический Журнал 12 (3), 1978, pp. 375-383
144. ↑ Chen Guan Fang: A new genus of Pliohyracinae (Hyracoidea, Mammalia) from the Late Pliocene of Dege, Sichuan, China. Vertebrata Palasiatica 41 (34), 2003, pp. 240-248
145. ↑ NP Kalmykov: The First Find of Hyrax (Mammalia, Hyracoidea, Postschizotherium) in Russia (Western Trans-Baikal region). Doklady Earth Sciences, 451 (2), 2013, pp. 827-829
146. ↑ Qiu Zhan-Xiang, Wei Qi, Pei Shu-Wen and Chen Zhe-Ying: Preliminary report of Postschizotherium (Mammalia: Hyracoidea) material from Tianzhen, Shanxi, China. Vertebrata Palasiatica 40 (2), 2002, pp. 146-160
147. ↑ ^{a b c} Herbert Hahn: From tree, bush and rock sleepers, the little relatives of the manatees and elephants. Wittenberg, 1959, ISBN 3-7403-0193-7
148. ↑ Johann Christian Daniel Schreber: The mammals in illustrations according to nature with descriptions. Fourth part. Erlangen, 1792, pp. 923–926 ( [36] )
149. ↑ Nancy Olds and Jehezekel Shoshani: Procavia capensis. Mammalian Species 171, 1982, pp. 1-7
150. ↑ Degree of endangerment of the individual species in the IUCN Red List of Threatened Species .

Web links

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Wiktionary: Hyrax  - explanations of meanings, word origins, synonyms, translations

• Hyraxes (English)
• Hyrax vocalizations calls of the hyrax , recorded as part of the Eastern Africa Primate Diversity and Conservation Program, last accessed on December 15, 2017

This version was added to the list of articles worth reading on February 4, 2006 .