Petinomys

Diversity

Petinomys is a genus of dwarf flying squirrels in family Sciuridae found in parts of Southeast Asia and the Indonesian islands. Within the genus there are eight described species: Petinomys crinitus , Petinomys fuscocapillus , Petinomys genibarbis , Petinomys hageni , Petinomys lugens , Petinomys mindanensis , Petinomys sagitta , Petinomys setosus , and Petinomys vordermanni .

Geographic Range

All Petinomys species are found in the Oriental biogeographic region. Each species has different extant ranges, with some overlap. Species P. genibarbis and P. setosus have large ranges and overlap for the entirety of the P. genibarbis range, while P. setosus has small populations outside of the main range. Petinomys hageni has the smallest range of all Petinomys species.

• Biogeographic Regions
• oriental oriental
  • native native

Habitat

All species of Petinomys are found in Asian forests. The genus spends a majority of its life in the tree canopy eating fruits and seeds. They create nests and spend the day in tree cavities. Habitat elevations range from sea level to 1700 m.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest

Systematic and Taxonomic History

Petinomys is in the Sciuridae family which includes chipmunks, squirrels, flying squirrels, ground squirrels, and marmots. There are a total of 52 genera in Sciuridae with Hylopetes (Southest Asian Flying Squirrels) and Petaurillus (Pygymy Flying Squirrels) being the closest related to Petinomys .

Petinomys has eight species recognized:

Basilan Flying Squirrel ( Petinomys crinitus ) Travancore Flying Squirrel ( Petinomys fuscocapillus ) Whiskered Flying Squirrel ( Petinomys genibarbis ) Hagen's Flying Squirrel ( Petinomys hageni ) Siberut Flying Squirrel ( Petinomy lugens ) Mindanao Flying Squirrel ( Petinomys mindanensis ) Temminck's Flying Squirrel ( Petinomys setosus ) Vordermann's Flying Squirrel ( Petinomys vordermanni )

Physical Description

All Petinomys species have the characteristic gliding membrane, which allows the squirrels to glide from tree to tree in their forest habitats. The genus has more forward facing eyes compared to other Sciuridae genuses. Petinomys species have a counter-shading fur pattern, lighter colored bellies and dark colored backs. Colors include white, blonde, brown, reddish-brown, and black. These colors also provide camouflage from predators while clinging onto trees. All species possess a black or red eye ring. Size is around 9 inches ( Petinomys setosus ) to 20 inches ( Petinomys fuscocapillus ) from head to tail. No sexual dimorphic traits or juvenile related traits have been observed.

Petinomys setosus , also known as Temminck's flying squirrel, has several polymorphs within its total extant range. Individuals of the Laos populations have more reddish-brown colors and lack a white-tipped tail compared to the dark brown, white-tipped tails of the Malaysian populations.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Not much is known about how Petinomys species mate, there have been no confirmed records of a mating event being documented. It is often assumed that the genus has a polygynandrous mating system due to there not being any sexual dimorphism between males and females and their solitary lifestyle.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Not much is known of Petinomys reproductive behaviors, no observations have been confirmed. It is assumed that Petinomys reproductive behaviors are similar to other Sciuridae genera.

• Key Reproductive Features
• iteroparous iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Not much is known of Petinomys reproduction, no observation of a litter has been confirmed. It is assumed that they take care of their young similar to other Sciuridae genera.

• Parental Investment
• altricial altricial
• female parental care female parental care

Lifespan/Longevity

Life expectancy is unknown due to lack of research.

Behavior

Petinomys species are arboreal, nocturnal seed and fruit eaters. Individuals are usually seen alone, which implies that these species are solitary. There is little information on territorial or other social behaviors.

• Key Behaviors
• arboreal arboreal
• glides
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary

Communication and Perception

Not much is known about Petinomys species communication. There is a record of a captive Malayan Whiskered Flying Squirrel ( Petinomys genibarbis ) making a soft whistling sound when alarmed, but the individual was otherwise silent.

• Communication Channels
• acoustic acoustic

• Perception Channels
• tactile tactile
• chemical chemical

Food Habits

Petinomys species are nocturnal frugivores and granivores. There have not been many observations of the genus actively eating. A scientist from Malaysia kept an individual Petinomys genibarbis in captivity and observed it eating rambutan, a native fruit to the region. There are no recordings of food behaviors.

• Primary Diet
• herbivore herbivore
  • frugivore frugivore
  • granivore granivore

Predation

Predators of Petinomys species include the Black eagle ( Ictinaetus malaiensis ), Spot-bellied eagle-owl ( Bubo nipalensis ), Changeable hawk-eagle ( Nisaetus cirrhatus ), Martens ( Martes flavigula and Martes gwatkinsi ), great hornbills, etc. Petinomys species are nocturnal, which allows them to avoid most of these predators while they are foraging. During the day, Petinomys species hide in tree cavities to avoid detection. They also have a range of brown and black fur colors that act as camouflage.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Petinomys species partake in important ecological tasks within their habitats as frugivores. Fruit and seed eating helps to spread plant seeds which diversify and regrow the forests they inhabit. Petinomys species have also been observed in facilitating pollination while foraging for fruits.

The genus also provides a food source to the ecosystem's predators such as the Black Eagle and Martens. Predation keeps Petinomys populations in check which prevents over consumption of fruits and seeds.

• Ecosystem Impact
• disperses seeds
• pollinates

Economic Importance for Humans: Positive

Petinomys has very minor positive impacts economically for humans. The genus participates in pollination albeit infrequently, which helps in production of crops.

• Positive Impacts
• pollinates crops

Economic Importance for Humans: Negative

Petinomys species are considered pest species and feed on crops.

• Negative Impacts
• crop pest

Conservation Status

All but one of the eight Petinomys species is decreasing in number. Petinomys crinitus is stable. Most cited cause for decline is deforestation of the genus's native habitat. Other listed causes are poaching, habitat fragmentation, and population fragmentation. There is also discussion on lack of population data, so some of the species may not be decreasing in number as much as is assumed.

Current conservation programs specifically for dwarf flying squirrels are non-existent. There are areas within the genus's extant ranges that have protections in place for land and water. More research on the species is needed for an action and recovery plan to take place.

Overall IUCN Red List ratings for the species in the genus are Least Concern and Vulnerable.

Additional Links

Encyclopedia of Life

Contributors

Ainsley Marks (author), Colorado State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Balakrishnan, P., K. Anoop Das, B. Patel, S. Sivaraman. 2022. Predation of Indian giant flying squirrel and Travancore flying squirrel in the Western Ghats, India. Mammalia , 86: 497-500.

Johnson-Murray, J. 1977. Myology of the gliding membranes of some petauristine rodents (genera: Glaucomys, Pteromys, Petinomys, and Petaurista). Journal of Mammalogy , 58: 374-384.

Kruskop, S., A. Abramov, V. Lebedev, A. Bannikova. 2022. Uncertainties in systematics of flying squirrels (Pteromyini, rodentia): Implications from a new record from Vietnam. Diversity , 14: 610.

Kumara, H., R. Suganthasakthivel. 2011. Predicting the potential distribution and conservation needs of Travancore flying squirrel, petinomys fuscocapillus, in peninsular India and Sri Lanka, using Garp. Tropical Conservation Science , 4: 172-186.

Liat, L. 1965. The Malayan whiskered flying squirrel petinomys genibarbis malaccanus. Proceedings of the Zoological Society of London , 144: 565-567.

Mercer, J., V. Roth. 2003. The Effects of Cenozoic Global Change on Squirrel Phylogeny. Science , 299: 1568-1572.

Muul, I., K. Thonglongya. 1971. Taxonomic status of Petinomys Morrisi (Carter) and its relationship to Petinomys setosus (Temminck and Schlegel).. Journal of Mammalogy , 52: 362.

Oshida, T., L. Lin, H. Yanagawa, H. Endo, R. Masuda. 2000. Phylogenetic relationships among six flying squirrel genera inferred from mitochondrial cytochromebgene sequences. Zoological Science , 17: 485-489.

Sanamxay, D., B. Douangboubpha, V. Xayaphet, P. Paphaphanh, T. Oshida, M. Motokawa. 2019. First record of petinomys setosus (rodentia: Sciuridae: Pteromyini) from Lao PDR. Mammal Study , 44: 1.

Singh, A., A. Bahuguna. 2016. Molecular phylogeny of rediscovered Travancore flying squirrel (petinomys fuscocapillus) and its conservation implications. Current Science , 110: 659.

Umapathy, G., A. Kumar. 2000. The occurrence of arboreal mammals in the rain forest fragments in the Anamalai Hills, South India. Biological Conservation , 92: 311-319.

2023. "Dwarf Flying Squirrels (genus Petinomys)" (On-line). iNaturalist. Accessed October 04, 2023 at https://www.inaturalist.org/taxa/45971-Petinomys .

2023. "IUCN Red List" (On-line). IUCN Red List. Accessed October 04, 2023 at https://www.iucnredlist.org/search?query=petinomys&searchType=species .

2023. "Petinomys" (On-line). Mindat.org. Accessed October 04, 2023 at https://www.mindat.org/taxon-2437248.html .

2016. "Small Flying Squirrel" (On-line). Encyclopedia of Life. Accessed October 04, 2023 at https://eol.org/pages/111058 .