Procaviidae

Procaviidae Vremenski raspon: kasni Miocen — danas
Dendrohyrax dorsalis
Naučna klasifikacija
Carstvo:	Animalia
Tip:	Chordata
Klasa:	Mammalia
Infraklasa:	Eutheria
Nadred:	Afrotheria
Red:	Hyracoidea Huxley, 1869
rodovi
Dendrohyrax † Gigantohyrax Heterohyrax Procavia

Procaviidae (savremeni damani) jesu mala sisarska familija iz reda damana. Obuhvata jedan izumrli i tri savremena roda, sa samo četiri savremene vrste. Naseljavaju Afriku i Arabijsko poluostrvo. Najstariji fosil, Heterohyrax auricampensis, potiče s početka kasnog Miocena.

Hyraxes have a life span from 9 to 14 years. Five extant species are recognised: the rock hyrax (Procavia capensis) and the yellow-spotted rock hyrax (Heterohyrax brucei), which both live on rock outcrops, including cliffs in Ethiopia and isolated granite outcrops called koppies in southern Africa; the western tree hyrax (Dendrohyrax dorsalis), southern tree hyrax (D. arboreus), and eastern tree hyrax (D. validus). Their distribution is limited to Africa, except for P. capensis, which is also found in the Middle East.

Karakteristike

Hyraxes retain or have redeveloped a number of primitive mammalian characteristics; in particular, they have poorly developed internal temperature regulation, for which they compensate by behavioural thermoregulation, such as huddling together and basking in the sun.

Savremeni damani su malih dimenzija i približno dostižu veličinu zeca. Dužina tijela se kreće između 30 i 60 cm. Imaju kratke ekstremitete, na prednjim nogama 4 prsta sa spljoštenim noktima nalik na kopito, a na zadnjim 3 prsta od kojih je jedan s kandžom. Od zuba, nedostaju im očnjaci umesto kojih postoji kratka dijastema. Zubna formula damana je:

1.0.4.3

2.0.4.3

A hyrax showing its characteristic chewing and grunting behavior and its incisor tusks

Although not ruminants, hyraxes have complex, multichambered stomachs that allow symbiotic bacteria to break down tough plant materials, but their overall ability to digest fibre is lower than that of the ungulates. Their mandibular motions are similar to chewing cud, but the hyrax is physically incapable of regurgitation as in the even-toed ungulates and the merycism of some of the macropods. This behaviour is referred to in a passage in the Bible which describes hyraxes as "chewing the cud". This chewing behaviour may be a form of agonistic behaviour when the animal feels threatened.

The hyrax does not construct dens, as most rodents do, but over the course of its lifetime rather seeks shelter in existing holes of great variety in size and configuration.

Hyraxes inhabit rocky terrain across sub-Saharan Africa and the Middle East. Their feet have rubbery pads with numerous sweat glands, which may help the animal maintain its grip when quickly moving up steep, rocky surfaces. Hyraxes have stumpy toes with hoof-like nails; four toes are on each front foot and three are on each back foot. They also have efficient kidneys, retaining water so that they can better survive in arid environments.

Female hyraxes give birth to up to four young after a gestation period of 7–8 months, depending on the species. The young are weaned at 1–5 months of age, and reach sexual maturity at 16–17 months.

Hyraxes live in small family groups, with a single male that aggressively defends the territory from rivals. Where living space is abundant, the male may have sole access to multiple groups of females, each with their own range. The remaining males live solitary lives, often on the periphery of areas controlled by larger males, and mate only with younger females.

Hyraxes have highly charged myoglobin, which has been inferred to reflect an aquatic ancestry.

Similarities with Proboscidea and Sirenia

Hyraxes share several unusual characteristics with mammalian orders Proboscidea (elephants and their extinct relatives) and Sirenia (manatees and dugongs), which have resulted in their all being placed in the taxon Paenungulata. Male hyraxes lack a scrotum and their testicles remain tucked up in their abdominal cavity next to the kidneys, as do those of elephants, manatees, and dugongs. Female hyraxes have a pair of teats near their armpits (axilla), as well as four teats in their groin (inguinal area); elephants have a pair of teats near their axillae, and dugongs and manatees have a pair of teats, one located close to each of the front flippers. The tusks of hyraxes develop from the incisor teeth as do the tusks of elephants; most mammalian tusks develop from the canines. Hyraxes, like elephants, have flattened nails on the tips of their digits, rather than the curved, elongated claws usually seen on mammals.

Evolucija

Pachyhyrax championi, a large fossil hyrax from the Miocene of Rusinga, Kenya (Natural History Museum collection)

All modern hyraxes are members of the family Procaviidae (the only living family within Hyracoidea) and are found only in Africa and the Middle East. In the past, however, hyraxes were more diverse and widespread. The order first appears in the fossil record at a site in the Middle East in the form of Dimaitherium, 37 million years ago. For many millions of years, hyraxes, proboscideans, and other afrotherian mammals were the primary terrestrial herbivores in Africa, just as odd-toed ungulates were in North America.

Through the middle to late Eocene, many different species existed, the largest of them weighing the same as a small horse and the smallest the size of a mouse. During the Miocene, however, competition from the newly developed bovids, which were very efficient grazers and browsers, displaced the hyraxes into marginal niches. Nevertheless, the order remained widespread and diverse as late as the end of the Pliocene (about two million years ago) with representatives throughout most of Africa, Europe, and Asia.

The descendants of the giant "hyracoids" (common ancestors to the hyraxes, elephants, and sirenians) evolved in different ways. Some became smaller, and evolved to become the modern hyrax family. Others appear to have taken to the water (perhaps like the modern capybara), ultimately giving rise to the elephant family and perhaps also the sirenians. DNA evidence supports this hypothesis, and the small modern hyraxes share numerous features with elephants, such as toenails, excellent hearing, sensitive pads on their feet, small tusks, good memory, higher brain functions compared with other similar mammals, and the shape of some of their bones.

Hyraxes are sometimes described as being the closest living relative of the elephant, although whether this is so is disputed. Recent morphological- and molecular-based classifications reveal the sirenians to be the closest living relatives of elephants. While hyraxes are closely related, they form a taxonomic outgroup to the assemblage of elephants, sirenians, and the extinct orders Embrithopoda and Desmostylia.

The extinct meridiungulate family Archaeohyracidae, consisting of four genera of notoungulate mammals known from the Paleocene through the Oligocene of South America, is a group unrelated to the true hyraxes.

Spisak rodova

Phylogeny of early hyracoids

Eutheria Afrotheria Hyracoidea   Seggeurius       Microhyrax     Saghatheriinae   Bunohyrax       Pachyhyrax       Thyrohyrax           Selenohyrax     Saghatherium         Titanohyrax     Antilohyrax         Megalohyrax           Geniohyiinae Geniohyus           Proboscidea (elephants)       Perissodactyla     Phenacodontidae

A phylogeny of hyracoids known from the early Eocene through the middle Oligocene epoch.

Hyracoidea

• †Dimaitherium
• †Helioseus?
• †Microhyrax
• †Seggeurius
• †Geniohyidae
  • †Brachyhyrax
  • †Bunohyrax
  • †Geniohyus
  • †Namahyrax
  • †Pachyhyrax
• †"Saghatheriidae" (Polyphyletic)
  • †Megalohyrax
  • †Regubahyrax
  • †Rukwalorax
  • †Saghatherium
  • †Selenohyrax
  • †Thyrohyrax
• †Titanohyracidae
  • †Afrohyrax
  • †Antilohyrax
  • †Rupestrohyrax
  • †Titanohyrax
• †Pliohyracidae
  • †Hengduanshanhyrax
  • †Kvabebihyrax
  • †Meroehyrax
  • †Parapliohyrax
  • †Pliohyrax
  • †Postschizotherium
  • †Prohyrax
• Procaviidae
  • Dendrohyrax (Tree hyrax)
  • †Gigantohyrax
  • Heterohyrax (Bush hyrax)
  • Procavia (Rock hyrax)

Stanište

Od najranijeg perioda familija je rasprostranjena samo u Africi, duž Crvenog mora na Afričkom i Azijskom kontinentu – Arabijsko poluostrvo. Savremeni damani naseljavaju različita staništa. Neki žive na stijenama, drugi u krošnji drveća, a postoje oni koji naseljavaju stepe. Na stijenama se uglavnom zavlače u šupljine, dok u stepama često naseljavaju prazne termitnjake. Hrane se biljnom hranom, lišćem, zeljastim biljem i sl., ali jedu i insekte i njihove larve.

Damani su na različite načine prilagođeni staništima koje neseljavaju. Zubima (kutnjacima) melju i sitne hranu. Imaju složen želudac i simbiotske bakterije koje im pomažu pri varenju. Bubrezi imaju sposobnost da zadržavaju vodu, što im omogućava da prežive sušne uslove. Na nogama imaju gumene jastučiće sa mnogobrojnim žlijezdama, a to im pomaže pri kretanju preko stijena.

Razmnožavanje

Žive u grupama ili porodicama od nekoliko jedinki, koje predvodi mužjak. Mužjak aktivno brani teritoriju koju zajednica naseljava. Ženka nosi mlade 7 do 8 mjeseci, a koti oko 4 mladunca, koji su polno zreli nakon 16 – 17 mjeseci. Mlađi mužjaci većinom žive solitarno, van područja koje kontroliše stariji mužjak, a pare se samo sa mlađim ženkama.

Klasifikacija

Familija Procaviidae obuhvata 4 savremene vrste:

• Dendrohyrax arboreus
  
• Dendrohyrax dorsalis
  
• Heterohyrax brucei
  
• Procavia capensis
  

Spoljašwe veze

• Медији везани за чланак Procaviidae на Викимедијиној остави
• Подаци везани за чланак Procaviidae на Викиврстама

Шаблон:Taxonbarlat