Rhynchocyon

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Rhynchocyon [1]
Rhynchocyon (7973324982).jpg
Rhynchocyon petersi
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Macroscelidea
Family: Macroscelididae
Genus: Rhynchocyon
Peters, 1847
Type species
Rhynchocyon cirnei
Peters, 1847
Species

Rhynchocyon chrysopygus
Rhynchocyon cirnei
Rhynchocyon petersi
Rhynchocyon stuhlmanni
Rhynchocyon udzungwensis

Rhynchocyon is a genus of elephant shrew (or sengi) in the family Macroscelididae. [1] Members of this genus are known colloquially as the checkered elephant shrews [2] or giant sengis. [3] It contains the following five species and several subspecies: [4] [5]

Ecology

The giant sengis are endemic to Africa, and usually live in lowland montane and dense forests, [7] often "avoiding" edges of forest patches. [8] [9] They eat primarily insects such as beetles, termites, ants, and centipedes, using their proboscises to dig them from the soil and its tongue to lick them up. [10] Their facial morphology limits their diets to tiny invertebrates, and unlike other members of Macroscelidea, do not supplement their diet with foods such as nuts or small fruits. [11]

They typically build ground level nests for shelter [12] requiring dry leaf litter. [13] The primary structure of a nest for R. udzungwensis, for example, consists of the excavation of a cup-like indentation in the soil, layered with leaves, and the covered with looser leaves as a roof covering. [14] They usually construct their nests at the base of trees. [14] They also use hollowed, fallen trees or trunks to retreat in shelter. [11]

They are typically active in the day (diurnal), spending their nights sheltered. Other Macroscelidea species are known to bask in the sun, as a method of thermoregulation to save energy. [11] Giant sengis do not bask—and it is most likely due to their adaptation to shaded canopy forest environments. [11]

Sengis live in monogamous pairs, defending hectare-sized territories. [15] [12] Pairs spend little time together except when the female is in estrous. [11] Mating occurs quickly and offspring grow quickly with minimal parental investment—none of which of is paternal. [11]

Identification

Each species exhibits distinct and varying coat patterns and colors. Species and subspecies found in denser forests exhibit darker coloration and patterns while open woodland species exhibit lighter, chequers. The darker species R. petersi, R. chrysopygus, and R. udzungwensis still contain vestigial chequers, but are masked by the blended dark fur between them. This makes coat patterns an unreliable indicator of species delineation though usefull for identification. [14] [16] The species are described as follows:

Taxonomy, distribution, and populations

Cladogram and associated geographic distribution of species and subspecies in the Rhynchocyon genus. Rhynchocyon Geographic Distribution and Phylogeny (2020).png
Cladogram and associated geographic distribution of species and subspecies in the Rhynchocyon genus.

The genus' taxonomic status has been difficult to determine due to the very close similarities between populations. Up to ten species have been recognized, but over time they have been regrouped into four species. [5] Recently, R. cirnei, the species with the most subspecies, has had R. c. stuhlmanni separated into its own species based on updated molecular data. [5]

R. chrysopygus, R. cirnei, and R. petersi are allopatrically distributed; with the more recently discovered R. udzungwensis and subspecies R. cirnei reichardi exhibiting parapatric distributions. [18] Some introgression (hybridization) has taken place between R. udzungwensis and R. cirnei reichardi as detected by mtDNA. [18] R. p. adersi is rare and unique in its distribution, being found isolated on the islands of the Zanzibar Archipelago. [19] R. c. reichardi is typically found in the Rift Valley highlands of Tanzania, Zambia, and Malawi, with R. c. hendersoni found in the highlands northern Malawi.

SpeciesLocalitiesElevation range (meters)IUCN Red List Status
R. chrysopygus Kenya (Arabuko-Sokoke Forest) [3] 30–360 m [20] Status iucn3.1 EN.svg
R. ch. mandelaiKenya (Boni National Reserve and Dodori National Reserve) [21]
R. cirnei Mozambique (north of Zambezi River); Malawi, Zambia and Tanzania (highlands within Rift Valley); Tanzania (south of Rufiji River) [22] 0–2100 m [22] Status iucn3.1 LC.svg
R. c. reichardiTanzania, Malawi, and Zambia (highlands) [5] 290–1800 m [18]
R. c. hendersoniNorthern Malawi (highlands) [5] Similar to R. udzungwensis [18]
R. c. shirensisSouthern Malawi (Shire Valley) [5] Similar to R. udzungwensis [18]
R. petersiTanzania (Eastern Arc Mountains, West and East Usambara, Nguru, Uluguru mountains, coastal fragmented forests from Rabai Hills and Diani Forest to Rufiji River. [23] 0-2020 m [4] [23] Status iucn3.1 LC.svg
R. p. adersiZanzibar archipelago (only Unguja Island, Mafia Island, and Uzi Island) [19] [23] Undetermined, though they are restricted to Zanzibar's and Mafia Island's highest elevations of 119 and 53 meters respectively.
R. stuhlmanniDemocratic Republic of Congo (between the Congo and Ubangi Rivers); Uganda (western forests surrounding Lake Albert, Mabira Central Forest Reserve east of Kampala) [22]
R. udzungwensis Udzungwa Mountains of Tanzania (Ndundulu-Luhomero and Mwanihana forests) [24] 350–2300 m [18] [24] Status iucn3.1 VU.svg

Both R. c. hendersoni and R. c. shirensis are known at higher elevations, similar to that of R. udzungwensis; however R. udzungwensis is unique in its larger body size [14] (being the largest giant sengi known [25] ). Bergmann's rule suggests that specialized ecological factors such as climate and temperature would favor larger bodies like that of R. udzungwensis, though the latter two species do not share this trait. [14] For comparison, R. udzungwensis occurs in greater abundance at elevations above 1000 meters, [18] has a body mass of 710 grams and a brain mass of 7131 milligrams, [25] while R. petersi occurs at greater abundance at elevations between 0-2000 meters, has a body mass of 471 g, and a brain mass of 5400 mg. [25]

Estimated of population size and density vary and can be difficult to determine. However, measurements of the species populations has been undertaken. R. chrysopygus, in protected areas, is about 150 individuals per square kilometer (about 14–20,000 individuals); [3] R. petersi is between 19–80 individuals per square kilometer; R. udzungwensis has an estimated 15,000–24,000 individuals. R. udzungwensis has a tiny distribution (restricted to submontane and montane forest in the Ndundulu–Luho-mero and Mwanihana forests) compared to the other species but resides in land. [14]

Cladogram of living Rhynchocyon [5]
  Rhynchocyon   

Unresolved taxonomic issues

Various classification issues still exist, with several undetermined questions left unresolved: [5]

Kenya subspecies

Mitochondrial DNA sequencing was conducted on a single specimen (dubbed the Boni giant sengi) from the Dodori and Boni national reserves in Kenya, [5] as there was suspicion that there may be another species present based on specimen capture, sightings, and camera trap images. [21]

The pelage pattern differs significantly from R. chrysopygus, [5] as it does not have the bright yellow patch on its rump. It also does not possess the same pelage traits as R. petersi—the Boni giant sengi has dark brown and black skin on its ears and tail whereas R. petersi has orange skin. It's face is griseous yellow-brown and the black fur on its rump does not extend to the middle of the back like it does in R. petersi. The single captured specimen weighs about 600 grams, lighter than R. udzungwensis, but heavier than R. petersi. It also has no noticeable chequers, though the dark fur patterns obscures these in all dark-colored giant sengis. [21] Despite the pelage differences, initial DNA comparisons find it nearly identical to R. chrysopygus. [5] A later DNA comparison supported a designation of a new subspecies, Rhynchocyon chrysopygus mandelai as it diverges in pelage and is allopatric to R. chrysopygus. [6]

Conservation

All species in the genus are threatened by habitat destruction. Forest fragmentation from human activities have created a patchwork of forest national parks and reseeves reserves. This has resulted in an uneven and variable level of protection. [4]

Related Research Articles

<span class="mw-page-title-main">Elephant shrew</span> Family of insectivorous mammals

Elephant shrews, also called jumping shrews or sengis, are small insectivorous mammals native to Africa, belonging to the family Macroscelididae, in the order Macroscelidea. Their traditional common English name "elephant shrew" comes from a perceived resemblance between their long noses and the trunk of an elephant, and their superficial similarity with shrews in the order Eulipotyphla. However, phylogenetic analysis has revealed that elephant shrews are not properly classified with true shrews, but are in fact more closely related to elephants than to shrews. In 1997, the biologist Jonathan Kingdon proposed that they instead be called "sengis", a term derived from the Bantu languages of Africa, and in 1998, they were classified into the new clade Afrotheria.

<span class="mw-page-title-main">Golden-rumped elephant shrew</span> Species of mammal

The golden-rumped elephant shrew is a small African mammal. It is the largest species of the elephant shrew family along with its close relative the grey-faced sengi. It is classified as endangered.

<span class="mw-page-title-main">Black and rufous elephant shrew</span> Species of mammal

The black and rufous elephant shrew, the black and rufous sengi, or the Zanj elephant shrew is one of the 17 species of elephant shrew found only in Africa. It is native to the lowland montane and dense forests of Kenya and Tanzania. Like other members of the genus Rhynchocyon, it is a relatively large species, with adults averaging about 28 cm (11 in) in length and 450–700 g (16–25 oz) in weight.

<span class="mw-page-title-main">Cape elephant shrew</span> Species of mammal

The Cape elephant shrew, also known as the Cape rock elephant-shrew or Cape rock sengi, is a species of elephant shrew in the family Macroscelididae. It is endemic to South Africa, although it is a relatively common animal. Its natural habitat is rocky areas. Elephant shrews are not closely related to other species of shrews and to rodents such as mice. E. edwardii has been observed to be a non-flying mammal pollinator of the pagoda lily. Elephant shrews are floral pollinators due to their largely insectivorous diet. Elephant-shrews are pollinators of Hyobanche atropurpurea. It uses its long slender tongue to feed on the pagoda lily's nectar while getting the lily's pollen on its long nose. E. edwardii is also a pollinator of Protea sulphurea.

<span class="mw-page-title-main">Dusky elephant shrew</span> Species of mammal

The dusky elephant shrew or dusky sengi is a species of elephant shrew in the family Macroscelididae. It is found in Malawi, Mozambique, and Zambia. Its natural habitat is dry savanna.

<span class="mw-page-title-main">Bushveld elephant shrew</span> Species of mammal

The bushveld elephant shrew or bushveld sengi is a species of elephant shrew in the family Macroscelididae. It is found in Angola, Botswana, Namibia, and South Africa. Its natural habitats are subtropical or tropical dry shrubland and hot deserts.

<span class="mw-page-title-main">Eastern rock elephant shrew</span> Species of mammal

The eastern rock elephant shrew or eastern rock sengi is a species of elephant shrew in the family Macroscelididae. It is found in Botswana, Mozambique, South Africa, and Zimbabwe. Its natural habitats are subtropical or tropical dry lowland grassland and rocky areas.

<span class="mw-page-title-main">Somali elephant shrew</span> Small animal of northeast Africa

The Somali elephant shrew or Somali sengi is a species of elephant shrew in the family Macroscelididae.

<span class="mw-page-title-main">North African elephant shrew</span> Species of mammal

The North African elephant shrew or North African sengi is a species of elephant shrew in the family Macroscelididae. It is found in Algeria, Libya, Morocco, and Tunisia, and is the only extant afrotherian within its range. The species was formerly classified in the genus Elephantulus, but molecular evidence indicates that it is more closely related to Petrodromus than to other members of Elephantulus. It was moved to a new genus, Petrosaltator, in 2016. The split with Petrodromus likely occurred during the Miocene period.

<i>Macroscelides proboscideus</i> Species of mammal

The round-eared elephant shrew or round-eared sengi, is a species of elephant shrew (sengi) in the family Macroscelididae. It is found in Botswana, Namibia, and South Africa. Its natural habitats are subtropical or tropical dry shrubland, and grassland, and hot deserts. They eat insects, shoots, and roots. Their gestation period is 56 days.

<span class="mw-page-title-main">Checkered elephant shrew</span> Species of mammal

The checkered elephant shrew or checkered sengi is a species of elephant shrew in the family Macroscelididae.

<span class="mw-page-title-main">Grey-faced sengi</span> Species of elephant shrew

The grey-faced sengi is a species of elephant shrew that is endemic to the Udzungwa Mountains of south-central Tanzania. The discovery of the species was announced in January 2008; only 15 species of elephant shrew were known until then, and the last discovery was made more than 120 years ago. As the name implies, the species is characterised by a distinctive grey face and a black rump, as well as being larger than the other species of elephant shrews.

<span class="mw-page-title-main">Karoo rock elephant shrew</span> Species of mammal

The Karoo rock elephant shrew or Karoo rock sengi is an elephant shrew in the genus Elephantulus. It is found in Northern Cape Province and Western Cape Province in South Africa.

<i>Macroscelides flavicaudatus</i> Species of mammal

Macroscelides flavicaudatus is a species of elephant shrew in the family Macroscelididae found in the central Namib desert and southern Namibia.

<i>Galegeeska</i> Genus of elephant shrew

Galegeeska is a genus of elephant shrew in the family Macroscelididae.

<span class="mw-page-title-main">Stuhlmann's elephant shrew</span> Species of Elephant shrew living in Africa

The Stuhlmann's elephant shrew is a species of elephant shrew that lives in the forests and savannas of Africa. It was discovered in 1893 and declared a new species. In the 1960s, however, it was downgraded to a subspecies of checkered sengi. In 2018, following genetic tests, scientists re-evaluated the mammal as a full species again.

<i>Eorhynchocyon</i> Extinct genus of mammals

Eorhynchocyon is an extinct mammal genus from the macroscelidid superfamily.

References

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  2. ↑ ITIS.gov
  3. 1 2 3 FitzGibbon, C.; Rathbun, G.B. (2015). "Rhynchocyon chrysopygus". IUCN Red List of Threatened Species . 2015: e.T19705A21287265. doi: 10.2305/IUCN.UK.2015-2.RLTS.T19705A21287265.en . Retrieved 12 November 2021.
  4. 1 2 3 Hoffmann Michael; Rathbun Galen B.; Rovero Francesco; Perkin Andrew; Owen Nisha; Burgess Neil (2016). "The distribution of the genus Rhynchocyon in the Eastern Arc Mountains, with an emphasis on the Black-and-rufous Sengi, Rhynchocyon petersi". Afrotherian Conservation. 12: 3–8.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 Carlen, E.J.; Rathbun, G.B.; Olson, L.E.; Sabuni, C.A.; Stanley, W.T.; Dumbacher, J.P. (2017). "Reconstructing the molecular phylogeny of giant sengis (Macroscelidea; Macroscelididae; Rhynchocyon)". Molecular Phylogenetics and Evolution. 113: 150–160. doi: 10.1016/j.ympev.2017.05.012 . PMID   28552433.
  6. 1 2 Agwanda B. R., Rovero F., Lawson L. P., Vernesi C., & Amin R. (2021), "A new subspecies of giant sengi (Macroscelidea: Rhynchocyon) from coastal Kenya", Zootaxa, 4948 (2): zootaxa.4948.2.5, doi:10.11646/zootaxa.4948.2.5, PMID   33757027 {{citation}}: CS1 maint: multiple names: authors list (link)
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  8. ↑ Rajan Amin, Bernard Agwanda, Tim Wacher, Bernard Ogwoka, Cedric Khayale, and Linus Kariuki (2020), "Habitat use of the endangered golden-rumped sengi Rhynchocyon chrysopygus", African Journal of Ecology, 59: 108–116, doi:10.1111/aje.12804, S2CID   225142032 {{citation}}: CS1 maint: multiple names: authors list (link)
  9. ↑ Francesco Rovero ,Emanuel Martin, Melissa Rosa, Jorge A. Ahumada, and Daniel Spitale (2014), "Estimating Species Richness and Modelling Habitat Preferences of Tropical Forest Mammals from Camera Trap Data", PLOS ONE, 9 (7): e103300, Bibcode:2014PLoSO...9j3300R, doi: 10.1371/journal.pone.0103300 , PMC   4108438 , PMID   25054806 {{citation}}: CS1 maint: multiple names: authors list (link)
  10. ↑ J. Kingdon (1997), The Kingdon Field Guide to African Mammals, Academic Press, pp. 142–152
  11. 1 2 3 4 5 6 Galen B. Rathbun (2009), "Why is there discordant diversity in sengi (Mammalia: Afrotheria: Macroscelidea) taxonomy and ecology?", African Journal of Ecology, 47 (1): 1–13, Bibcode:2009AfJEc..47....1R, doi:10.1111/j.1365-2028.2009.01102.x
  12. 1 2 G. B. Rathbun (1979), "The social structure and ecology of elephant-shrews", Journal of Comparative Ethology, 20: 1–77
  13. ↑ Norbert J. Cordeiro; Nathalie Seddon; David R. Capper; Jonathan M. M. Ekstrom; Kim M. Howell; Isabel S. Isherwood; Charles A. M. Msuya; Jonas T. Mushi; Andrew W. Perkin; Robert G. Pople & William T. Stanley (2005), "Notes on the ecology and status of some forest mammals in four Eastern Arc Mountains", Journal of East African Natural History, 94 (1): 175–189, doi:10.2982/0012-8317(2005)94[175:noteas]2.0.co;2, S2CID   85816994
  14. 1 2 3 4 5 6 7 8 9 10 11 F. Rovero, G. B. Rathbun, A. Perkin, T. Jones, D. O. Ribble, C. Leonard, R. R. Mwakisoma, and N. Doggart (2007), "A new species of giant sengi or elephant-shrew (genus Rhynchocyon) highlights the exceptional biodiversity of the Udzungwa Mountains of Tanzania", Journal of Zoology, 274 (2): 126–133, doi: 10.1111/j.1469-7998.2007.00363.x {{citation}}: CS1 maint: multiple names: authors list (link)
  15. ↑ C. D. Fitzgibbon & G. B. Rathbun (1994), "Surveying Rhynchocyon elephant-shrews in tropical forest", African Journal of Ecology, 32 (1): 50–57, Bibcode:1994AfJEc..32...50F, doi:10.1111/j.1365-2028.1994.tb00554.x
  16. 1 2 3 Galen B. Rathbun (2017), "Identifying the different forms of giant sengi (Rhynchocyon) based on external colour patterns" (PDF), Afrotherian Conservation, 13
  17. ↑ Corbet, G.B., Hanks, J., 1968. A revision of the elephant-shrews, family Macroscelididae. Bull. Br. Museum (Natural Hist.) Zool. 16, 45–111.
  18. 1 2 3 4 5 6 7 Lucinda P. Lawson; Cristiano Vernesi; Silvia Ricci & Francesco Rovero (2013), "Evolutionary History of the Grey-Faced Sengi, Rhynchocyon udzungwensis, from Tanzania: A Molecular and Species Distribution Modelling Approach", PLOS ONE, 8 (8): e72506, Bibcode:2013PLoSO...872506L, doi: 10.1371/journal.pone.0072506 , PMC   3754996 , PMID   24015252
  19. 1 2 Galen B. Rathbun (1995), "Conservation issues and strategies for elephant-shrews", Mammal Review, 25 (1–2): 79–86, doi:10.1111/j.1365-2907.1995.tb00440.x
  20. ↑ Clare D. FitzGibbon (1994), "The distribution and abundance of the golden-rumped elephant-shrew Rhynchocyon chrysopygus in Kenyan coastal forests", Biological Conservation, 67 (2): 153–160, Bibcode:1994BCons..67..153F, doi:10.1016/0006-3207(94)90361-1
  21. 1 2 3 Samuel Andanje, Bernard Risky Agwanda, Grace W. Ngaruiya, Rajan Amin, & Galen B. Rathbun (2010), "Sengi (Elephant-Shrew) Observations from Northern Coastal Kenya", Journal of East African Natural History, 99 (1): 1–8, doi:10.2982/028.099.0101 {{citation}}: CS1 maint: multiple names: authors list (link)
  22. 1 2 3 Hoffman, M. (2020) [amended version of 2017 assessment]. "Rhynchocyon cirnei". IUCN Red List of Threatened Species . 2020: e.T19709A166489513. doi: 10.2305/IUCN.UK.2020-1.RLTS.T19709A166489513.en . Retrieved 17 April 2024.
  23. 1 2 3 Hoffmann, M.; Burgess, N.; Rovero, F. (2016). "Rhynchocyon petersi". IUCN Red List of Threatened Species . 2016: e.T19708A21286959. doi: 10.2305/IUCN.UK.2016-1.RLTS.T19708A21286959.en . Retrieved 17 April 2024.
  24. 1 2 Rovero, F. & Rathbun, G.B. (2015). "Rhynchocyon udzungwensis". IUCN Red List of Threatened Species . 2015: e.T136309A21287423. doi: 10.2305/IUCN.UK.2015-2.RLTS.T136309A21287423.en . Retrieved 17 April 2024.
  25. 1 2 3 Jason A. Kaufman, Gregory H. Turner, Patricia A. Holroyd, Francesco Rovero, & Ari Grossman1 (2013), "Brain Volume of the Newly-Discovered Species Rhynchocyon udzungwensis (Mammalia: Afrotheria: Macroscelidea): Implications for Encephalization in Sengis", PLOS ONE, 8 (3): e58667, Bibcode:2013PLoSO...858667K, doi: 10.1371/journal.pone.0058667 , PMID   23516530 {{citation}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)

Sengis.org is an overview website concerning all the sengi species maintained by researcher Galen B Rathbun of the university of the California Academy of Sciences. It hosts images, videos, bibliographies, among other topics about the order Macroscelididae.

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