Hispaniolan solenodon

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Hispaniolan solenodon [1]
Hispaniolan Solenodon crop.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Eulipotyphla
Family: Solenodontidae
Genus: Solenodon
Species:
S. paradoxus
Binomial name
Solenodon paradoxus
Brandt, 1833
Hispaniolan Solenodon area.png
Hispaniolan solenodon range (brown)

The Hispaniolan solenodon (Solenodon paradoxus), also known as the agouta, [3] is a small, furry, shrew-like mammal endemic to the Caribbean island of Hispaniola (in the Dominican Republic and Haiti). Like other solenodons, it is a venomous, insect-eating animal that lives in burrows and is active at night. It is an elusive animal and was only first described in 1833; its numbers are stable in protected forests but it remains the focus of conservation efforts.

Contents

Its smaller sister species of the same genus, Marcano's solenodon (S. marconoi) became extinct after European colonization. The Hispaniolan solenodon and the rat-like Hispaniolan hutia live in the same habitats and are the only surviving mammals native to the island.

Discovery

In 1833 the Russian Academy of Sciences received a new specimen from Haiti. Puzzled by the animal, curator Johann Friedrich von Brandt named it Solenodon paradoxus. (Solenodon means "grooved teeth".) No more information was known other than a relation to the Cuban solenodon (Atopogale cubana) discovered in 1861, and it was believed to be extinct. Addison Emery Verrill and Alpheus Hyatt Verrill rediscovered the animal in the Dominican Republic in 1907, but by 1964 it was again believed extinct. [4]

Description

Illustration Hispaniolan solenodon.jpg
Illustration

The Hispaniolan solenodon resembles an oversized shrew; males and females are similar in size. Adults measure 49 to 72 cm (19 to 28 in) in total length, including a tail 20 to 25 cm (7.9 to 9.8 in) long, and weigh about 800 g (28 oz) on average. This makes them the largest extant members of the Soricomorpha. Although they are somewhat variable in colour, they are typically dusky brown over most of the body, with a paler underside and reddish fur on the sides of the head, throat, and upper chest. The tail, legs, snout, and eyelids are hairless. [5]

The forelegs are noticeably more developed than the hind legs, but all have strong claws useful for digging. The head is large in relation to its body, with a long rostrum and tiny eyes and ears partially hidden by the body fur. The nostrils open to the side and the snout has about a dozen long whiskers, up to 7 cm (2.8 in) in length, with a few smaller whiskers further back on the head. [5] A unique feature is the os proboscidis, a bone extending forward from the nasal opening to support the snout cartilage; this is not found even in other solenodons. [6]

The dental formula for the species is 3.1.3.33.1.3.3 × 2 = 40. The second lower incisor has a narrow tubular channel that is almost entirely enclosed, through which flows a venomous saliva secreted by the submaxillary gland. [7] Although the exact chemical composition of the venom is unknown, [8] injection of 0.38 to 0.55 mg of venom per gram of body mass has been shown to be fatal to mice in two to six minutes. [5]

Hispaniolan solenodons have patches of skin rich in apocrine glands on the thighs. The secretions of these glands are used in communication between individuals. [9]

Distribution and habitat

Hispaniolan solenodona are found only on the island of Hispaniola, in the Dominican Republic and parts of southern Haiti. Their habitat is usually undisturbed moist forest below 1,000 m (3,300 ft) elevation, although they are sometimes found at higher altitudes or close to developed agricultural land. [2] [5] There are two recognised subspecies:

The Hispaniolan solenodon appears to have a patchy distribution. Populations are found both within and outside protected areas such as the Jaragua, Del Este and Sierra de Baoruco National Parks. In Haiti, it is reported from La Visite National Park and the Duchity region of the Massif de la Hotte. [10] Its presence in Los Haitises National Park in the Dominican Republic is inferred, but unconfirmed.

Behavior

Hispaniolan solenodons are nocturnal; during daylight hours, they stay in their burrows, trees, hollowed-out logs or caves, remaining hidden from view. Their burrows may contain multiple chambers and tunnels and are typically inhabited by an adult pair accompanied by up to six younger family members. When they emerge into the open air, they run on the soles of their feet, following an erratic, zigzag course. [5]

Hispaniolan solenodons feed mainly on arthropods, but will also eat worms, snails, mice and small reptiles; they may also feed on a small amount of fruit, grains, and leaf litter. They probe the earth with their snouts and dig or rip open rotten logs with their claws. They have been reported to make a number of vocalisations, including a loud defensive "chirp", an aggressive "squeal", a soft "squeak" when encountering familiar conspecifics, and a high-pitched "clic" when encountering strangers. They have also been reported to make echolocation clicks at 9 to 31 kHz. [5]

Reproduction

Breeding occurs throughout the year, although the females are receptive only for short periods once every ten days or so. Litters of one to three young are born after a gestation period of over 84 days. Usually, only two of the offspring survive, because the female only has two teats, which are found towards the groin. The young are born blind and hairless, and weighing 40 to 55 g (1.4 to 1.9 oz). They are carried about by the mother for the first two months of life, although it is unknown how long it takes for them to be fully weaned. They can live for over eleven years in captivity. [5]

Ecology

A specimen in the wild Solenodon jun 09 0061 crop.JPG
A specimen in the wild

The Hispaniolan solenodon is preyed upon by the ashy-faced owl (Tyto glaucops) and the Stygian owl (Asio stygius). [11] Because of a lack of natural land predators, the Hispaniolan solenodon did not evolve defenses, and it is a slow, clumsy runner. Feral dog and cat populations have become established, and small Asian mongooses (Urva auropunctata) were introduced to control rats in sugar cane fields; all three can potentially prey on solenodons.

Evolution

In 2016, researchers at the University of Illinois and the University of Puerto Rico completely sequenced the mitochondrial genome of the Hispaniolan solenodon. The study confirmed that solenodons diverged from all other living mammals about 78 million years ago. The study also found that there is much greater genetic diversity among the northern population than the southern population. [12] [13] This timeline aligns well with a hypothesis on how the Hispaniolan solenodon came to inhabit the island of Hispaniola. Geologists speculate that the island was part of a volcanic arc that connected to Mexico around 75 million years ago. [14]

Conservation

Today, the solenodon is one of the last two surviving native insectivorous mammals found in the Caribbean, and one of the only two remaining endemic terrestrial mammal species of Hispaniola. [15]

While the survival of the solenodon is uncertain, talk of conservation has been underway through the "Last Survivors Project", which has been collaborating with the Dominican government. In 2009, a five-year plan for conservation was funded which has been put in place to conduct field research, discover the best means by which to bring about their conservation, and organize monitoring tools to ensure their long-term survival. [16] [17]

One of the aims of the conservation efforts is to increase local awareness of the species, particularly in the Dominican Republic. The Ornithological Society of Hispaniola showed pictures of the solenodon to the locals in both countries, and few knew what they were due to their nocturnal nature. [18] The Hispaniolan solenodon was identified as one of the top ten "focal species" in 2007 by the EDGE Species project. [19] A collaborative conservation project funded by the Darwin Initiative (UK) was started in 2009 and is researching the species to conserve it. [20] The species is fully protected by law. However, national parks in both Haiti and the Dominican Republic are threatened by deforestation and encroachment for farming and charcoal production. The US Agency for International Development and the Nature Conservancy are[ as of? ] working with local nongovernmental organisations to improve protection and implement management plans for these parks (the "Parks in Peril" programme). A recovery plan for the isolated Haitian population, published in 1992, advocated comprehensive surveys, improved management of the Pic Macaya National Park, education campaigns, control of exotic mammals, and an ex situ breeding programme. These recommendations have not yet[ as of? ] been implemented.

Two conservation research and education programmes funded by the Darwin Initiative have recently been established, focusing on solenodons in both countries: "Building evidence and capacity to conserve Hispaniola's endemic land mammals" (started 2009), and "Building a future for Haiti's unique vertebrates" (started 2010). These collaborative projects represent a partnership between the EDGE Programme, the Durrell Wildlife Conservation Trust, BirdLife International, the Sociedad Ornitologica de la Hispaniola, the Dominican Republic National Zoo, Societe Audubon Haiti, and in-country project partners.

Habitat loss and predation by introduced species have contributed to it being considered an endangered species in the past. It was considered almost extinct until 1907, when it was found living in the interior of Hispaniola. It was not considered to be in immediate danger early in the 20th century. In 1966, it was found in several localities in the Dominican Republic. In 1981, after extensive searching, the Hispaniolan solenodon was declared "functionally extinct" in Haiti, persisting only in the remote mountains of the south. In 1987, it was still found in both countries, but was thought to be particularly threatened in Haiti. As of 1996, it could still be found in both countries. Wildlife filmmaker Jürgen Hoppe has been able to film the Hispaniolan solenodon in various parts of the Dominican Republic during the last 18 years.[ as of? ] The most recent sightings in the wild (with video evidence) were during the summer of 2008, when a team of researchers from the Durrell Wildlife Conservation Trust and the Ornithological Society of Hispaniola were able to trap an individual specimen. The researchers took physical measurements and DNA from it before releasing it back into the wild. [21]

Follow up work sequencing the whole genomes of six captured individuals more accurately predicts that solenodons diverged from other extant mammals 73.6 million years ago. Looking at single-nucleotide polymorphism (SNP) variation between northern and southern captured individuals enabled the researchers to infer population demography, which supported a likely subspecies split (S. paradoxus woodi the proposed name for the southern subspecies) within the Hispaniolan solenodon at least 300 thousand years ago. [22] The solenodon was downlisted from "Endangered" to "Least Concern" by the IUCN in 2020, on the basis of an increased awareness of its population size and range.

Related Research Articles

<span class="mw-page-title-main">Hispaniola</span> Caribbean island shared by the Dominican Republic and Haiti

Hispaniola is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and the region's second largest in area, after the island of Cuba.

<span class="mw-page-title-main">Eulipotyphla</span> Order of mammals

Eulipotyphla is an order of mammals suggested by molecular methods of phylogenetic reconstruction, which includes the laurasiatherian members of the now-invalid polyphyletic order Lipotyphla, but not the afrotherian members.

<span class="mw-page-title-main">Cuban solenodon</span> Species of mammal

The Cuban solenodon or almiquí is a small, furry, shrew-like mammal endemic to mountainous forests on Cuba. It is the only species in the genus Atopogale. An elusive animal, it lives in burrows and is only active at night when it uses its unusual toxic saliva to feed on insects. The solenodons, native to the Caribbean, are one of only a few mammals that are venomous.

<span class="mw-page-title-main">Solenodon</span> Family of mammals

Solenodons are venomous, nocturnal, burrowing, insectivorous mammals belonging to the family Solenodontidae. The two living solenodon species are the Cuban solenodon and the Hispaniolan solenodon. Threats to both species include habitat destruction and predation by non-native cats, dogs, and mongooses, introduced by humans to the solenodons' home islands to control snakes and rodents.

<span class="mw-page-title-main">Pico Duarte</span> Mountain in the Dominican Republic

Pico Duarte is the highest peak in the Dominican Republic, on the island of Hispaniola and in all the Caribbean. At 3,101 m (10,174 ft) above sea level, it gives Hispaniola the 16th-highest maximum elevation of any island in the world. Additionally, it is only 85 kilometres northeast of the region's lowest point, Lake Enriquillo, 46 m below sea level. It is part of the Cordillera Central range, which extends from the plains between San Cristóbal and Baní to the northwestern peninsula of Haiti, where it is known as the Massif du Nord. The highest elevations of the Cordillera Central are found in the Pico Duarte and Valle Nuevo massifs.

<span class="mw-page-title-main">Venomous mammal</span> Venom-producing animals of the class Mammalia

Venomous mammals are animals of the class Mammalia that produce venom, which they use to kill or disable prey, to defend themselves from predators or conspecifics or in agonistic encounters. Mammalian venoms form a heterogeneous group with different compositions and modes of action, from three orders of mammals: Eulipotyphla, Monotremata, and Chiroptera. It has been proposed that some members of a fourth order, Primates, are venomous. To explain the rarity of venom delivery in Mammalia, Mark Dufton of the University of Strathclyde has suggested that modern mammalian predators do not need venom because they are able to kill quickly with their teeth or claws, whereas venom, no matter how sophisticated, requires time to disable prey.

<i>Nesophontes</i> Extinct family of mammals

Nesophontes, sometimes called West Indies shrews, is the sole genus of the extinct, monotypic mammal family Nesophontidae in the order Eulipotyphla. These animals were small insectivores, about 5 to 15 cm long, with a long slender snout and head and a long tail. They were endemic to the Greater Antilles, in Cuba, Hispaniola, Puerto Rico, the United States Virgin Islands, and the Cayman Islands.

<span class="mw-page-title-main">Hispaniolan hutia</span> Species of rodent endemic to Hispaniola

The Hispaniolan hutia is a small, endangered, rat-like mammal endemic to forests on the Caribbean island of Hispaniola. It lives in burrows or trees, and is active at night when it feeds on roots and fruits. A member of the hutia subfamily (Capromyinae), it is endangered from habitat loss and introduced species, such as rats or mongoose.

<span class="mw-page-title-main">Soricomorpha</span> Formerly used suborder of mammals

Soricomorpha is a formerly used taxon within the class of mammals. In the past it formed a significant group within the former order Insectivora. However, Insectivora was shown to be polyphyletic and various new orders were split off from it, including Afrosoricida, Macroscelidea, and Erinaceomorpha, with the four remaining extant and recent families of Soricomorpha shown here then being treated as a separate order. Insectivora was left empty and disbanded.

<span class="mw-page-title-main">Rhinoceros iguana</span> Species of iguana endemic to the Caribbean

The rhinoceros iguana is an endangered species of iguana that is endemic to the Caribbean island of Hispaniola and its surrounding islands. A large lizard, they vary in length from 60 to 136 centimetres, and skin colours range from a steely grey to a dark green and even brown. Their name derives from the bony-plated pseudo-horn or outgrowth which resembles the horn of a rhinoceros on the iguana's snout. It is known to coexist with the Ricord's iguana ; the two species are the only taxa of rock iguana to do so.

<span class="mw-page-title-main">Golden swallow</span> Species of bird

The golden swallow is a swallow endemic to the Caribbean island of Hispaniola and was once native to Jamaica, but is now extirpated there. It is restricted to isolated montane forests that primarily consist of the Hispaniolan pine. This species is considered to be a vulnerable species by the International Union for Conservation of Nature (IUCN). The exact cause of its extirpation from Jamaica is unknown, but likely factors include predation by introduced mammals and habitat loss, although the habitat loss theory is not supported by much evidence. The last sighting of the nominate subspecies was in Hardwar Gap, with three birds being seen on 8 June 1989.

<i>Cyclura ricordii</i> Species of iguana endemic to Hispaniola

Cyclura ricordii, also known as Ricord's ground iguana or Ricord's rock iguana, is an endangered species of medium-sized rock iguana, a large herbivorous lizard. It is endemic to the island of Hispaniola. It is known to coexist with the nominate subspecies of the rhinoceros iguana ; the two species are the only taxa of rock iguana to do so. The natural habitats of its three subpopulations are hot, dry, wooded savanna on limestone with access to soil and sandy flats in southern Hispaniola. It is threatened by predation by introduced predators and habitat loss, due to overgrazing and charcoal manufacture.

The St. Michel nesophontes is an extinct species of mammal in the family Nesophontidae. It was endemic to Hispaniola.

Marcano's solenodon is an extinct species of mammal in the family Solenodontidae known only from skeletal remains found on the island of Hispaniola.

The Caribbean bioregion is a biogeographic region that includes the islands of the Caribbean Sea and nearby Atlantic islands, which share a fauna, flora and mycobiota distinct from surrounding bioregions.

<i>Leiocephalus personatus</i> Species of lizard

The Hispaniolan masked curly-tailed lizard is a lizard species from the family of curly-tailed lizard (Leiocephalidae). It is also known as the Hispaniolan masked curlytail, Haitian curlytail lizard and the green-legged curly-tail. endemic to the Caribbean island of Hispaniola.

<span class="mw-page-title-main">Wildlife of Haiti</span>

The wildlife of Haiti is important to the country because of its biodiversity. According to the World Conservation Monitoring Centre, Haiti is considered to be "one of the most biologically significant countries of the West Indies". With an estimated 5,600 plant species on the island of Hispaniola, some of which only occur in Haiti, 36% are considered as endemic to the island. A mountainous area country, it is situated in the western three-eighths of Hispaniola and shares a border with the Dominican Republic. There are nine life zones, from low desert to high cloud forests, as well as four mountain ranges, and hundreds of rivers and streams and the coral reefs in the seas that surround the islands. Issues of environmental damage, expanding population, deforesting and erosion are of concern; less than 2% of the original forest remains on account of deforestation. This degradation is traced from the 17th century to 19th century starting with the French colonization of the Haiti and population explosion during the 20th century and for the purpose of forestry and sugar-related industries, degraded the forests. and the environment.

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