Juliana's gold mole
| Juliana's gold mole | ||||||||||||
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| Neamblysomus julianae | ||||||||||||
| ( Meester , 1972) |
Juliana's gold mole ( Neamblysomus julianae ) is a representative of the gold mole . It is endemic to southern Africa , but is only known there from three clearly separated subpopulations that are distributed over northeastern South Africa . The species has a light body structure, but - like the other gold mulle - is characterized by a spindle-shaped body with externally invisible ears and tail as well as by the strong claws of the forefeet. Due to the graceful construction, Julianas Goldmull is bound to loose, sandy soils in rocky landscapes. There are hardly any studies on the way of life, the animals are solitary and live underground, the main diet consists of invertebrates . It was first described in 1972. The population is viewed as severely threatened in connection with changes in the landscape and due to the highly fragmented distribution area and the specialized way of life.
features
Habitus
Julianas Goldmull is a smaller representative of the Goldmull and compared to Gunnings Goldmull ( Neamblysomus gunningi ) the smaller of the two species of the genus Neamblysomus . It has a head to torso length of 9.2 to 11.1 cm, the weight varies from 21 to 35 g. A sexual dimorphism is not very pronounced, males appear toward female average heavier. However, due to the small number of individuals examined so far, this difference cannot yet be considered certain. The physique of Julianas Goldmull is very delicate, characteristic of all Goldmulle the body has a spindle-shaped form, while the tail and the ears are not externally visible. Julianas Goldmull appears very light in color. The back fur is cinnamon to reddish brown, along the center line of the back it is darker than on the sides, where it changes into a fawn tint. The underside is cloudy reddish brown in color. The outer hairs have a whitish to yellowish base, turn gray towards the middle and are tinted reddish to fawn brown at the tip. On the muzzle, on the cheeks and on the throat there are spots of whitish hair, sometimes whitish spots of color also appear in the area of the eyes hidden under the fur and skin, as well as on the backs of the front and rear feet. The limbs are generally short and strong. They end in four-pointed hands at the front and five-pointed feet at the back, each with claws. On the forefoot, the claw of the central ray (III) is typically particularly large, it becomes 8.5 to 10 mm long and is 3.6 to 4.3 mm wide at the base. But it has a comparatively slimmer construction than other, more closely related gold mulls. The claw of the second finger is slightly shorter than the middle claw at 5.8 to 6.7 mm, that of the first finger is significantly shorter and only extends to the attachment point of the second claw. On the fourth finger, however, there is a greatly reduced, partly button-like claw. The entire rear foot becomes 9 to 14 mm long.
Skull and dentition features
The greatest length of the skull is 21.8 to 23.6 mm, the greatest width 14.7 to 16.7 mm. The skull looks significantly shorter and wider compared to that of Gunnings Goldmull, so that the greatest width is around 67 to 70% of the length. The palate width is 30 to 32% of the length of the skull, which is also wider than Gunnings Goldmull. There are hardly any differences between males and females in terms of skull dimensions. The teeth comprises 36 teeth, it has the following tooth formula on . A rearmost, third molar is usually not formed in the upper jaw, in the lower jaw it appears regularly but variably in the individual halves of the jaw. It has a nail-like shape and is on average smaller than the front molars, which are characterized by a tricuspid chewing surface pattern. There is no pronounced talonid on the lower molars. The length of the upper row of teeth from the canine to the second molar is 5.5 to 6.1 mm.
distribution
Juliana's gold mole is endemic to southern Africa , the population is limited to three narrowly defined subpopulations . The first occurs on the Bronberg Ridge in the eastern part of Pretoria (metropolitan area Tshwane ) in the South African province of Gauteng , a quartzite mound less than 15 km long and 1 km wide with sandy substrates between the rock outcrops. Proven locations are here at Willows, Shere and Tierpoort on the north slope and Olympus and Zwavelpoort on the south slope of the ridge. The second population is distributed over various localities in the southwestern part of the Kruger National Park in the Mpumalanga Province , such as Numbi Gate, Petroniuskop and Matjulwana. The third population was discovered in 1974, but only confirmed in 1989, it exists in the flood plains of the Nylsvley Provincial Natural Reserve , an approximately 40 km² large protected area, and south bordering farm lands in the Limpopo province . The three populations are separated from each other 120 km in north-south direction (Pretoria and Nylsvley reserve) and 350 km in east-west direction (Pretoria and Kruger National Park). The entire occurrence of the species extends to a total of 160 km², of which 9 km² are in the region near Pretoria and 8 km² on the Nylsvley reserve, and lies entirely in the eastern Zambezi woodland zone, the population of the Nylsvley reserve lives within this the thorny bushveld , that of the Kruger National Park the Bushveld-Lowfeld and that of Pretoria the rocky highveld. Individual vault finds of owls from Witcoppen Cave 25 km east of the Nylsvley reserve speak for a significantly wider distribution of Juliana's gold mole in the region, which is also suggested by calculation models for usable habitats . Likewise, an individual observed near Malelane in Mpumalanga in 2003 points to a more extensive occurrence there. The species is associated with sandy soils, mostly with medium-grain sand substrates and little variation in the size of the sand particles, which makes the subsoil very loose. It therefore mainly prefers areas with weathered sandstone in the rocky surroundings of the South African savannahs ; for this reason, its habitat within the individual localities is again very narrowly defined. In the more humid grasslands with firmer clay soils of the Mpumalanga province, Juliana's gold mole is replaced by the robust gold mole ( Amblysomus robustus ) and the highveld gold mole ( Amblysomus septentrionalis ). Juliana's gold mole also occurs in well-watered gardens. They occur locally quite frequently, in beneficial habitats the population density can be 2 to 3 individuals per hectare .
Way of life
The way of life of Julianas Goldmull is largely unexplored. The animals live solitary and build burrows underground. The tunnel systems run close to the surface at a depth of 3 to 15 cm and are recognizable as earth ripples above ground. Individual corridors spiral in 40 to 50 cm depth but without ending in a chamber or a nest. The graceful physique binds Julianas Goldmull to loose sandy soils, whereby the animals represent "sand swimmers", comparable to the desert goldmull ( Eremitalpa granti ). Due to their small size, they are able to dig through narrow crevices underground. The individual individuals behave territorially and defend their territories aggressively against conspecifics of both sexes. When distressed, they utter high-pitched squeaks.
It is generally assumed that Julianas Goldmull is nocturnal, but studies of animals from the Nylsvley Provincial Natural Reserve in Limpopo have shown a two-phase activity with peak times from around 9:00 a.m. to 1:00 p.m. and 7:00 p.m. to 11:00 p.m. On average, the activity lasts three to five hours, interrupted by longer periods of extensive inactivity. Within 24 hours, an animal used an area of 3964 m² in the Nylsvley Provincial Natural Reserve and traveled up to 304 m. The majority was completed at night, which suggests that the daily activity phase could be used for thermoregulation . Shortly after sunrise the animals fall into a torpor , at this time of day the ground has cooled down considerably. Julianas Goldmull's body temperature varies between 27 and 33 ° C, depending on the activity. Resting stiffness may occur even at slightly lower ambient temperatures and are accompanied by a drop in body temperature, which is to be assessed as an energy-saving effect in a cooler ambient temperature. The torpor can probably be lower in the cold season than in the warmer months. The animals counteract overheating by looking for shady places. Activity on the surface of the earth increases significantly, especially after intense rainfall.
Foraging takes place in tunnel systems running close to the surface. The main diet consists of invertebrates , the exact composition of the diet is unknown. An animal in human care ate cockroaches , grasshoppers , beetles and other insects as well as earthworms , but avoided snails . Most of the time it spent its prey in a burrow, rather seldom it consumed its food directly on the surface. The duration and intensity of foraging in the near-surface tunnels decreases significantly during the dry winter months from May to September. Mother and young animals have been observed from July to August and from November to February. This suggests a multiple, but seasonally dependent reproduction with a low rate of reproduction over the year. The number of offspring is two per litter. The barn owl is a natural predator , and the remains of Juliana's gold mole are occasionally found in its ridges. This also reflects the relatively frequent occurrence of the species on the earth's surface.
Systematics
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Internal systematics of the gold mole according to Asher et al. 2010
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Juliana's gold mole is a species from the genus Neamblysomus , to which Gunnings gold mole ( Neamblysomus gunningi ) is also counted. The genus forms part of the golden mole family (Chrysochloridae), which includes small, soil-digging mammals from the parentage of Afrotheria . Its members are endemic to Africa , the main area of distribution is in southern Africa, but a few species are also found in parts of eastern or central Africa. Due to the subterranean way of life, the habitats of the individual species have narrow boundaries with a few exceptions. Two ecological groups can be distinguished within the family. The first group includes the representatives dry to some semi-desert landscapes colonize such as Grant's golden mole ( Eremitalpa ) or chrysochloris ( Chrysochloris ). The second group is from residents of open grass and savannah formed, as well as woods, such as the copper gold Mullen ( Amblyomus ), and representatives of the genus Neamblysomus , moreover, also the giant gold Mullen ( Chrysospalax ) or Arends' Goldmull ( Carpitalpa ). The internal structure of the family has not yet been satisfactorily clarified. A common distinction is based on the construction of the hammer in the middle ear , according to which two or three subfamilies can be distinguished: the Amblysominae with a normally built malleus, the Chrysochlorinae with a greatly elongated head of the malleus and the Eremitalpinae with a spherically inflated head of the malleus. Some authors see the latter two as a single subfamily, the Chrysochlorinae. Molecular genetic studies have not yet been able to fully understand this subdivision of the gold mole based on differences in skeletal anatomy. According to them, however, Carpitalpa and Amblysomus are the closest relatives of Neamblysomus .
There are no known subspecies of Juliana's gold mole. The three subpopulations differ in the color of their fur and in individual tooth features. The two western occurrences ( Pretoria and Nylsvley Provincial Natural Reserve ) are characterized by a light cinnamon-colored back and a fawn-colored belly, they also lack the lower third molar. The animals of the Kruger National Park, on the other hand, have a darker reddish-brown fur on their backs and a rather cloudy red-brown belly. A lower, posterior molar is often formed, but rather small in shape with only a third the size of the previous molar. Preliminary genetic studies also show a clear separation between the eastern and the two western subpopulations. Further research is needed to determine whether the two groups can be distinguished at the species level.
Jurgens AJ Meester provided the first scientific description in 1972. He described the populations of Pretoria and the Kruger National Park and named them Amblysomus julianae as a member of the copper gold mole. As a type region, he gave the suburb of Willows on the northern slope of the Bronberg Ridge in Pretoria. The holotype represents a female individual that was already collected there in October 1965. One of the other paratypes, a male, comes from nearby Shere and was kept in human care for a long time until July 1972. The epithet devoted Meester his wife. As early as the early 1960s, animals were observed in the Kruger National Park that were initially assigned to Sclater's gold mole ( Chlorotalpa sclateri ) and were only recognized as belonging to this species when Juliana's gold mole was described. Julianas Goldmull was assigned to the genus Neamblysomus in the mid-1990s due to deviations in the karyotype and in the tooth features. These showed that the species, together with Gunnings Goldmull, form a clade separated from the Coppergoldmull , which later genetic studies confirmed.
Hazard and protection
The total population of Julianas Goldmull is divided into three separate subpopulations, within which the animals are again limited to narrow habitats due to their highly specialized way of life. The large distances between the three subpopulations do not allow any previously known gene flow . Two of the subpopulations are partly in protected areas (Nylsvley Provincial Natural Reserve and Kruger National Park). The areas outside the protected areas are subject to strong changes due to humans. The main threat to the population of the species is therefore loss of suitable habitat through conversion and increasing fragmentation as a result of the expansion of settlements and the increase in agriculture or mining (especially quartzite). The latter mainly affects the subpopulation on the Bronberg Ridge near Pretoria, which is not subject to any protective measures. Their area of distribution has been affected by more extensive mining measures since 2003, which among other things will affect a large part of the landscape that is beneficial to Julianas Goldmull in the foreseeable future and also prevent the east-west migration corridor. Already at the beginning of the 21st century, one-third of the habitat were by mining and the rapid already about urbanization converted and the entire region has been carved up by two connecting roads in several parts. The subpopulations living in the nature reserves can also be affected by infrastructure projects during the tourist development of the regions. Hunting by domestic dogs and house cats also have a subordinate effect on the population, as do expulsions by garden owners. The IUCN lists Juliana Goldmull to as "critically endangered" ( endangered ), the Bronberg Ridge subpopulation but as "threatened with extinction" ( critically endangered ).
literature
- Gary N. Bronner and Nigel C. Bennett: Neamblysomus julianae Meester 1972 - Juliana's Golden mole. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 15-16
- Gary N. Bronner: Neamblysomus julianae Juliana's Golden-mole. 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. 256-257
- William A. Taylor, Samantha Mynhardt and Sarita Maree: Chrysochloridae (Golden moles). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 180–203 (pp. 199–200) ISBN 978-84-16728-08-4
Individual evidence
- ↑ a b c d J. Meester: A new golden mole from the Transvaal (Mammalia: Chrysochloridae). Annals of the Transvaal Museum 28 (4), 1972, pp. 35-46
- ↑ a b c d e f g h i j Gary N. Bronner and Nigel C. Bennett: Neamblysomus julianae Meester 1972 - Juliana's Golden mole. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 15-16
- ↑ a b c d e f g h Gary N. Bronner: Neamblysomus julianae Juliana's Golden-mole. 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. 256-257
- ^ A b c d e f William A. Taylor, Samantha Mynhardt and Sarita Maree: Chrysochloridae (Golden moles). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 180–203 (pp. 199–200) ISBN 978-84-16728-08-4
- ^ A b c Craig R. Jackson and Mark P. Robertson: Predicting the potential distribution of an endangered cryptic subterranean mammal from few occurrence records. Journal for Nature Conservation 19, 2011, pp. 87-94
- ^ Gary N. Bronner: New distribution records for four mammal species, with notes on their taxonomy and ecology. Koedoe 33 (2), 1990, pp. 1-7
- ↑ Craig R. Jackson, Trine Hay Setsaas, Mark P. Robertson and Nigel C. Bennett: Ecological variables governing habitat suitability and the distribution of the endangered Juliana's golden mole. African Zoology 43 (2), 2008, pp. 245-255
- ↑ a b c S. Maree: Neamblysomus julianae. The IUCN Red List of Threatened Species 2015. e.T1089A21285354 ( [1] ); last accessed on December 17, 2015
- ^ A b Craig R. Jackson, NR Lubbe, Mark P. Robertson, Trine H. Setsaas, J. van der Waals and Nigel C. Bennett: Soil properties and the distribution of the endangered Juliana's golden mole. Journal of Zoology 274, 2008, pp. 13-17
- ↑ Craig R. Jackson, Trine H. Setsaas, Mark P. Robertson, M. Scantlebury, and Nigel C. Bennett: Insights into torpor and behavioral thermoregulation of the endangered Juliana's golden mole. Journal of Zoology 278, 2009, pp. 299-307
- ↑ a b c Robert J. Asher, Sarita Maree, Gary Bronner, Nigel C. Bennett, Paulette Bloomer, Paul Czechowski, Matthias Meyer and Michael Hofreiter: A phylogenetic estimate for golden moles (Mammalia, Afrotheria, Chrysochloridae). MC Evolutionary Biology 10, 2010, p. 69 doi : 10.1186 / 1471-2148-10-69
- ^ Alberto M. Simonetta: A new golden mole from Somalia with an appendix on the taxonomy of the family Chrysochloridae (Mammalia, Insectivora). Monitore Zoologico Italiano NS Supplement 2, 1968, pp. 27-55
- ^ Gary N. Bronner: Family Chrysochloridae Golden-moles. 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. 223-225
- ^ Gary N. Bronner: Cytogenetic Properties of Nine Species of Golden Moles (Insectivora: Chrysochloridae). Journal of Mammalogy 76 (3), 1995, pp. 957-971
- ^ Gary N. Bronner, M. Hoffmann, PJ Taylor, CT Chimimba, PB Best, CA Matthee and TJ Robinson: A revised systematic checklist of the extant mammals of the southern African subregion. Durban Museum Novitates 28, 2003, pp. 56-95
- ↑ Sarita Maree, Gary Bronner, Craig Jackson and Nigel Bennett: The conservation of golden moles (Afrosoricida; Chrysochloridae) with emphasis on the status of Neamblysomus julianae in South Africa. Afrotherian Conservation 2, 2003, pp. 4-6
- ^ Sarita Maree: Planning for persistence of a Juliana's Golden Mole (Neamblysomus julianae) subpopulation threatened by urban development on Bronberg Ridge of Pretoria (Tshwane), South Africa. Afrotherian Conservation 13, 2017, pp. 24–33
- ^ S. Maree: Neamblysomus julianae (Bronberg Ridge subpopulation). The IUCN Red List of Threatened Species 2015. e.T62010A21284251 ( [2] ); last accessed on December 17, 2015
Web links
- Neamblysomus julianae in the Red List of Threatened Species of IUCN , 2015. Posted by: Maree, 2014. Accessed December 17, 2015.
- Neamblysomus julianae Bronberg Ridge subpopulation in the Red List of Threatened Species of IUCN , 2015. Posted by: Maree, 2014. Accessed December 17, 2015.