Laonastes aenigmamus Jenkins, Kilpatrick, Robinson & Timmins, 2005

Nguyen, Dang Xuan, Nguyen, Nghia Xuan, Nguyen, Duy Dinh, Dinh, Tri Huy, Le, Dinh Thuc & Dinh, Duong Hai, 2014, Distribution and habitat of the Laotian Rock Rat Laonastesaenigmamus Jenkins, Kilpatrick, Robinson & Timmins, 2005 (Rodentia: Diatomyidae) in Vietnam, Biodiversity Data Journal 2, pp. 4188-4188 : 4188

Laonastes aenigmamus Jenkins, Kilpatrick, Robinson & Timmins, 2005

Materials

Type status: Other material. Occurrence: recordedBy: Nghia Xuan Nguyen; individualCount: 1; sex: male; Location: country: Vietnam; stateProvince: Quang Binh; verbatimLocality: Thuong Hoa Commune, Minh Hoa District; verbatimElevation: 200-350m; verbatimLatitude: 17°40 ’39’' N; verbatimLongitude: 105°57 ’22’’ E; Event: samplingProtocol: trapping; eventDate: 6 Sept 2011; habitat: Karst forest; Record Level: collectionID: PNKB-NXN21; institutionCode: IEBR; collectionCode: DVZ-Rodentia

Type status: Other material. Occurrence: recordedBy: Nghia Xuan Nguyen; individualCount: 1; sex: unkown; Location: country: Vietnam; stateProvince: Quang Binh; verbatimLocality: Thuong Hoa Commune, Minh Hoa District; verbatimElevation: 200-350m; verbatimLatitude: 17°40 ’05’' N; verbatimLongitude: 105°56 ’27’’ E; Event: samplingProtocol: trapping; eventDate: 3 Sept 2011; habitat: Karst forest; Record Level: collectionID: PNKB-NXN232; institutionCode: IEBR; collectionCode: DVZ-Rodentia

Type status: Other material. Occurrence: recordedBy: Nghia Xuan Nguyen; individualCount: 1; sex: unkown; Location: country: Vietnam; stateProvince: Quang Binh; verbatimLocality: Thuong Hoa Commune, Minh Hoa District; verbatimElevation: 200-350m; verbatimLatitude: 17°40 ’55’' N; verbatimLongitude: 105°54 ’40’’ E; Event: samplingProtocol: trapping; eventDate: 7 April 2012; habitat: Karst forest; Record Level: collectionID: PNKB-NXN231; institutionCode: IEBR; collectionCode: DVZ-Rodentia

Type status: Other material. Occurrence: recordedBy: Nghia Xuan Nguyen; individualCount: 1; sex: unkown; Location: country: Vietnam; stateProvince: Quang Binh; verbatimLocality: Thuong Hoa Commune, Minh Hoa District; verbatimElevation: 200-350m; verbatimLatitude: 17°40 ’32’' N; verbatimLongitude: 105°57 ’52’’ E; Event: samplingProtocol: trapping; eventDate: 22 December 2013; habitat: Karst forest; Record Level: collectionID: PNKB-NXN181; institutionCode: IEBR; collectionCode: DVZ-Rodentia

Type status: Other material. Occurrence: recordedBy: Nghia Xuan Nguyen; individualCount: 1; sex: Male; Location: country: Vietnam; stateProvince: Quang Binh; verbatimLocality: Thuong Hoa Commune, Minh Hoa District; verbatimElevation: 200-350m; verbatimLatitude: 17°40 ’07’' N; verbatimLongitude: 105°56 ’06’’ E; Event: samplingProtocol: trapping; eventDate: 12 April 2014; habitat: Karst forest; Record Level: collectionID: PNKB-NXN219; institutionCode: IEBR; collectionCode: DVZ-Rodentia

Type status: Other material. Occurrence: recordedBy: Nghia Xuan Nguyen; individualCount: 1; sex: Female; Location: country: Vietnam; stateProvince: Quang Binh; verbatimLocality: Thuong Hoa Commune, Minh Hoa District; verbatimElevation: 200-350m; verbatimLatitude: 17°40 ’27’' N; verbatimLongitude: 105°55 ’05’’ E; Event: samplingProtocol: trapping; eventDate: 15 April 2014; habitat: Karst forest; Record Level: collectionID: Released to the wild

Type status: Other material. Occurrence: recordedBy: Nghia Xuan Nguyen; individualCount: 1; sex: Female; Location: country: Vietnam; stateProvince: Quang Binh; verbatimLocality: Thuong Hoa Commune, Minh Hoa District; verbatimElevation: 200-350m; verbatimLatitude: 17°40 ’03’' N; verbatimLongitude: 105°56 ’27’’ E; Event: samplingProtocol: trapping; eventDate: 15 April 2014; habitat: Karst forest; Record Level: collectionID: PNKB-NXN223; institutionCode: IEBR; collectionCode: DVZ-Rodentia

Type status: Other material. Occurrence: recordedBy: Nghia Xuan Nguyen; individualCount: 1; sex: Female; Location: country: Vietnam; stateProvince: Quang Binh; verbatimLocality: Thuong Hoa Commune, Minh Hoa District; verbatimElevation: 200-350m; verbatimLatitude: 17°40 ’03’' N; verbatimLongitude: 105°56 ’27’’ E; Event: samplingProtocol: trapping; eventDate: 18 April 2014; habitat: Karst forest; Record Level: collectionID: PNKB-NXN224; institutionCode: IEBR; collectionCode: DVZ-Rodentia

Type status: Other material. Occurrence: recordedBy: Nghia Xuan Nguyen; individualCount: 1; sex: Female; Location: country: Vietnam; stateProvince: Quang Binh; verbatimLocality: Thuong Hoa Commune, Minh Hoa District; verbatimElevation: 200-350m; verbatimLatitude: 17°40 ’39’' N; verbatimLongitude: 105°57 ’34’’ E; Event: samplingProtocol: trapping; eventDate: 5 May 2014; habitat: Karst forest; Record Level: collectionID: PNKB-NXN225; institutionCode: IEBR; collectionCode: DVZ-Rodentia

Type status: Other material. Occurrence: recordedBy: Nghia Xuan Nguyen; individualCount: 1; sex: Male; Location: country: Vietnam; stateProvince: Quang Binh; verbatimLocality: Thuong Hoa Commune, Minh Hoa District; verbatimElevation: 200-350m; verbatimLatitude: 17°41 ’13’' N; verbatimLongitude: 105°53 ’51’’ E; Event: samplingProtocol: trapping; eventDate: 27 June 2014; habitat: Karst forest; Record Level: collectionID: PNKB-NXN230; institutionCode: IEBR; collectionCode: DVZ-Rodentia

Description

Fig. 1

Fig. 2

Distribution

Interviews of local villagers indicated that the Laotian Rock Rat has been found at 35 localities in Thuong Hoa commune (24 localities), Hoa Son commune (9 localities) and Dan Hoa commune (2 localities) (Fig. 3). The interviewees also reported the occurrence of the Laotian Rock Rat in limestone forest extending from Thuong Hoa and Hoa Son communes to two neighboring communes, Trung Hoa and Hoa Hop. Cage traps and box traps were set up in 12 localities within these communes for a total of 9,050 trap-nights in April and May 2014. Only one live specimen of the Laotian Rock Rat was caught in Thuong Hoa commune (17°40'28"N; 105°55'05"E). This low trapping success can be explained by very low density of the Laotian Rock Rat in the survey area and because of dry season weather. As reported by local villagers, small mammal trapping success is always very low in dry season (from January to June). The live animal was released into the wild after taking its body measurements and monitoring it for a few days in semi-wild conditions. In total, during the period from the first reports of the Laotian Rock Rat in PNKB NP in September 2011 to October 2014, we collected 12 specimens of the species (one live animal and 11 dead specimens collected by local villagers) and checked coordinates of all these localities for the species distribution mapping. The distribution map of the Laotian Rock Rat was established based on data from the village interview surveys comprising 35 localities reported by villagers and 12 localities confirmed by our field surveys. The map showed that the distributional range of the Laotian Rock Rat in PNKB NP area covered about 150 km2 of limestone evergreen forests belonging to five communes (Thuong Hoa, Hoa Son, Trung Hoa, Hoa Hop and Dan Hoa) of Minh Hoa District, Quang Binh Province (Fig. 3).

Ecology

Habitat and feeding ecology: The Laotian Rock Rat was found only in limestone evergreen forest on karst slopes (Fig. 4). This species has never been found in montane forest, forest in valleys, or in residential areas or in agricultural fields within the forests, but they can be found on karst slopes just 1-2 km away from villages or several hundred metres away from agricultural fields. The Laotian Rock Rat lives in the lower part of steep karst towers (100-300 m above valley base) with many rock boulders and crevices under tall limestone forest. The animals avoid living in the very low part of karst slopes where seasonal flooding occurs during the rainy season, and their dens are found far away from streams. Laotian Rock Rats use small rock crevices for their dens. During the day time, they hide in the dens, and at night they go out for foraging in forest floor next to the dens. The Laotian Rock Rat was not found in bare karst, but lives only in karst slopes under tall forest (moist evergreen forest) on limestone under 700 m asl (Fig. 4).

Most of the forested area has been affected by selected timber logging; however, a 3-4 layer forest structure remains, with the following characters:

The canopy tree layer consists of trees 20-25 m high with stem diameter 0.5-0.8 m. The most common trees species are: Pometia pinnata ( Sapindaceae ), Dracontomelon duperreanum ( Anacardiaceae ), Toona surenii ( Meliaceae ), Paviesia anamensis ( Sapindaceae ), Pterospermum grewiaefolium ( Sterculiaceae ), Mahuca sp., Hopea sp., Streblus asper ( Moraceae ), Litsea sp. ( Lauraceae ), Sumbaviopsis macrophylla ( Euphorbiaceae ), Actinodaphne sp. ( Lauraceae ), Pometia chinensis ( Sapindaceae ), Choerospondias axillaris ( Anacardiaceae ), Alangium ridleyi ( Alangiaceae ), Knema sp. ( Myristicaceae ); etc.

The middle tree layer consists of trees 10-15 m high with stem diameter of 0.3-0.5 m. The most common species are Knema corticosa ( Myristicaceae ); Streblus tonkinensis , Streblus asper ( Moraceae ), Xylopia vielana ( Annonaceae ), Diospyros sp. ( Ebenaceae ), Caryota mitis ( Arecaceae ), Arenga pinnata ( Arecaceae ), Camelia sp. ( Theaceae ), Actinodaphne sp. ( Lauraceae ), Pterospermum sp. ( Sterculiaceae ), Litsea sp.( Lauraceae ), Ormosia laoensis ( Fabaceae ), Nephelium lappaceum ( Sapindaceae ), Sumbaviopsis macrophylla ( Euphorbiaceae ), Paranephelium spirei ( Sapindaceae ), Alangium ridleyi ( Alangiaceae ), Baccaurea sp. ( Euphorbiaceae ), Aglaia sp. ( Meliaceae ), etc.

The scrub layer consists of trees 3-7 m high, mostly with twisted stems, many branches, and several stems rising from one base. The most common species are from the families Euphorbiaceae , Theaceae , Myrtaceae and Verbenaceae . Some dominant species are Antidesma sp. ( Euphorbiaceae ), Trevesia panmalta ( Araliaceae ), Litsea valiabilis ( Lauraceae ), Arenga pinnata ( Arecaceae ), Excoecaria cochinchinensis ( Euphorbiaceae ), as well as seedlings of trees from higher layers.

The herb and fern layer is about 0.5-3 m high, with trees of 0.2-3 m high from family Araceae , the genera Calamus and Caryota (family Arecaceae ), and many herb species from various families ( Urticaceae , Melastomataceae , Balsaminaceae , Poaceae , Begoniaceae , Podipoliaceae , Convallariaceae , Zingiberaceae , Urticaceae , Acanthaceae ). Some of the most common species are Homalomena occulta ( Araceae ), Aglaonema simplex ( Araceae ), Aglaonema siamensis ( Araceae ), Tacca chantrieri ( Taccaceae ), Aspidistra typica ( Convallariaceae ), Piper sp. ( Piperaceae ), Corymborkis veratrifolia (Orchidaeceae), etc.

Local villagers reported that the Laotian Rock Rat feeds exclusively on plant parts (leaves, roots and fruits) of various plant species. Stomach content analysis, examination of food remains dropped in dens, and observation of a live Laotian Rock Rat in semi-wild conditions showed that the species feeds mostly on plant parts, but also some insects, as follows:

Young leaves and buds of Aglaonema simplex ( Araceae ), Streblus asper ( Moraceae ), Dracontomelon duperreamum ( Anacardiaceae ), Pometia chinensis ( Sapindaceae ), Ficus sp. ( Moraceae ), Acanthopanax trifoliatus ( Araliaceae ), Perilla frutescens ( Lamiaceae ), Psidium guajava ( Myrtaceae ), Zea mays ( Poaceae ), Prunus persica ( Rosaceae )

Ripe fruits of Streblus asper ( Moraceae ), Ficus sp. ( Moraceae ), Dracontomelon duperreamum ( Anacardiaceae ), Alangium ridleyi ( Alangiaceae ), Lythocarpus fenestratus ( Fagaceae ), Musa paradisiaca , Musa uranoscapos ( Musaceae )

Seeds of Zea mays ( Poaceae )

Roots of Manihot esculenta ( Euphorbiaceae ) and Aglaonema simplex ( Araceae )

Insects: Cicada ( Cicadidae ), Mantis ( Mantidae ), Grasshopper ( Acrididae )

Conservation

The distribution range of the Laotian Rock Rat in PNKB NP is very small (approximately 150 km2) and located close to the villages of ethnic minorities (Ruc, Sach, Chut). These minority groups are very poor and their livelihood depends on wildlife and forest products. Wildlife hunting is a long tradition of the local people, and a practice that remains extensive currently. Most men 15 to 60 years in age in these villages are engaged in wildlife hunting. Their hunting season lasts about eight months per year (from July to February). The most widely used means for trapping the Laotian Rock Rat and other small animals is a metal spring snare, which has a high trapping success and can trap animals of various body size, such as rats, civets, large birds, and snakes. Snap traps are also used because they are easily made in the forest from bamboo and small trees. Each hunter usually keeps 30-100 active snares in forests; some hunters keep up to 300-500 active snares. It is estimated that 30-35 specimens of the Laotian Rock Rat are trapped by local villagers each year in the survey area. Other threats to the natural habitat of the Laotian Rock Rat include forest clearance for agricultural fields, removal of timber trees, collecting firewood and other forest products that lead to degradation of forest quality, and habitat modification. At present, no specific conservation measures are being undertaken aside from awareness education for local villagers.