A Survey of Small Mammals from Mt. Tay Con Linh II, Vietnam, with the Description of a New Species of Chodsigoa (Insectivora: Soricidae)
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Mammal Study 28: 31–46 (2003) © the Mammalogical Society of Japan A survey of small mammals from Mt. Tay Con Linh II, Vietnam, with the description of a new species of Chodsigoa (Insectivora: Soricidae) Darrin P. Lunde1,*, Guy G. Musser1 and Nguyen Truong Son2 1 Division of Vertebrate Zoology (Mammalogy), American Museum of Natural History, Central Park West @ 79th Street, New York, NY 10024, USA 2 Department of Zoology, Institute of Ecology and Biological Resources, 18 Hoang Quoc Viet Road, Cau Giay, Hanoi, Vietnam Abstract. A survey of small mammals from Mt. Tay Con Linh II, Ha Giang Province, Vietnam (22°45’27”N, 104°49’49”E) resulted in the capture of 17 species of bat, insectivore, and rodent: Cynopterus sphinx, Rousettus leschenaulti, Sphaerias blanfordi, Scaptonyx fusicaudus, Chodsigoa parca, Chodsigoa caovansunga new species, Blarinella griselda, Crocidura attenuata, Crocidura fuliginosa, Crocidura wuchihensis, Belomys pearsonii, Callosciurus inornatus, Leopoldamys edwardsi, Niviventer fulvescens, Niviventer langbianis, Niviventer tenaster and Chiropodomys gliroides. In addition Ratufa bicolor and Tamiops sp. are reported from observations. Scaptonyx fusicaudus and Blarinella griselda represent new distributional records for Vietnam. As part of the process of identifying specimens of Vietnamese Chodsigoa, we examined specimens of C. lamula and C. parva, including the holotype of parva and concluded that C. parva is not synonymous with C. lamula but actually represents a separate, very small species currently known only from the type locality in Yunnan, China. Key words: biodiversity, Chodsigoa, mammals, Vietnam. Vietnam’s northern frontier was once an expanse of subtropical forest but is now almost entirely converted to grassland or savanna (Wikramanayake et al. 2002). Only very small fragments of forest remain in secluded mountainous regions but these are currently under threat, and the opportunity to study their native fauna is fast disappearing (MacKinnon 1997; Wikramanayake et al. 2002). As part of an effort to document small mammal species diversity from this region we surveyed Mt. Tay Con Linh II (22°45’27”N, 104°49’49”E; Fig. 1). Subtropical forest still exists here at altitudes above approx- imately 1200 m and from our base camp at 1400 m we collected small mammals along a transect extending all the way to the summit at 2200 m. Descriptions of habitats encountered along our study transect are as follows: 1250–1550 m — Disturbed subtropical forest with an estimated canopy height of between 20–25 m. There was a lush understory of shrubs, saplings and woody lianas. Most canopy trees were about 60 cm diameter breast height (dbh) but on precipitous slopes we ob- Fig. 1. Map of the northern half of Vietnam showing the location of Mt. Tay Con Linh II and the extent of remaining forest habitat. * To whom correspondence should be addressed. E-mail: [email protected] 32 Mammal Study 28 (2003) Fig. 2. Habitat at approximately 1600 m altitude, Mt. Tay Con Linh II, Vietnam. Note the rather steep terrain and dead bamboo stems and rather dense ground cover vegetation. Photographed November 1, 2001. Fig. 3. Habitat at approximately 2000 m altitude, Mt. Tay Con Linh Fig. 4. Habitat at approximately 2000 m altitude, Mt. Tay Con II, Vietnam showing a pitfall trapline running through a dense stand of Linh II, Vietnam. Victor traps were tied to lianas like those pictured. solid-stemmed bamboo. Photographed October 30, 2001. Photographed October 29, 2001. Lunde et al., Small mammals in Vietnam 33 served a few trees that appeared to be much larger. The addition to these conventional traps we employed four topography was very steep with small 5–10 meter wide separate pitfall traplines after the design depicted in Voss granite-bottomed streams in deep ravines. et al. (2001) except our lines differed in the numbers of 1550–1650 m — Similar to the habitat described from pitfalls per line. Habitats sampled using pitfall traplines just below 1550 m but with an understory that was appar- include those described for the following altitudes: 1300 ently once dominated by a species of hollow bamboo. m (19 buckets); 1500 m (7 buckets); and two separate The bamboo was either cut down or had died off by the pitfall traplines in close proximity at 2000 m (10 and 11 time of our survey and all that remained were clusters of buckets; Fig. 3). Four 12-meter mist nets were set in rotting bamboo stems beneath a lush ground cover of open areas just above our camp but bat netting repre- shrubs (Fig. 2). sented a secondary component of our sampling efforts 1650–1850 m — Similar to the habitat described and we did not record net meter-hours. below 1650 m but with a greater abundance of very Specimens were fixed in formalin solution (3.75% large trees some of which exceeded 150 cm dbh. Thick formaldehyde) and are now preserved in 70% ethanol. clusters of a species of hollow bamboo dominated the Liver samples were preserved in lysis buffer prior to understory reaching heights of approximately 4–5 m. fixation. Skulls were extracted and cleaned from many Nearly every surface beneath the canopy was covered specimens. Limits of standard external body measure- in a heavy mat of moss. This altitudinal zone was often ments taken in the field are abbreviated: TL (total enveloped in mist and was always dripping wet. The length); T (tail length); HF (hind foot length); E (ear topography was less steep than below. length); FA (forearm length, bats only); TIB (tibia 1850–2100 m — Here the forest canopy reached a length, bats only). Values for head and body length maximum height of about 15–20 m. There was a rather (HB) were obtained by subtracting tail length from sharply demarcated vegetational change from the domi- total length. Weight was recorded in grams. Cranial nant stands of hollow bamboo below 1850 m to a species measurements follow Bates and Harrison (1997) for bats; of solid, thin-stemmed (2–3 cm diameter) bamboo that Hoffmann (1985) for Scaptonyx and Soricinae; and reached heights of 3–4 meters. Monospecific stands of Musser (1979) for murid rodents. The names, locations this bamboo dominated the understory (Figs. 3 and 4). and acronyms for museum collections referred to in this 2100–2200 m (summit) — The canopy height within report are: The American Museum of Natural History, this altitude range was estimated at between 10–15 m. New York (AMNH), The Natural History Museum, There were some thin-stemmed bamboo plants in the London (BMNH), and the Institute for Ecology and understory but these did not form dense stands like those Biological Resources, Hanoi (IEBR). between 1850–2100 m. Likewise there was some moss but not the thick mats seen below. Stunted, lichen- Results festooned trees at the north face of the summit did not exceed a height of 5 meters. We report 17 species of bat, insectivore and rodent from Mt. Tay Con Linh II based on 222 voucher speci- Methods mens (217 collected as a result of the present survey plus 5 additional specimens collected by Christine Johnson Fieldwork was conducted between 29 September and from the same locality one year prior to our survey). The 3 November, 2001 (DPL and NTS). A variety of small following species accounts provide relevant taxonomic mammal traps, including Victor snap-traps, Sherman live notes along with altitudinal and microhabitat informa- traps, Tomahawk cage traps and Conibear traps, were tion for each species collected. A complete listing of used to collect as many species as possible. Traps were specimens collected is provided in the Appendix. The set where small mammals were likely to occur such as on specimens were cataloged in the AMNH but half of lianas and tree branches (Fig. 4), in dense vegetation, and these will be sent to the Department of Zoology IEBR. along animal pathways. The type of trap employed and the length of time that a trap was allowed to remain in Order Chiroptera one place depended on the experience of the trapper. Family Pteropodidae Traps were baited with a mixture of peanut butter, Cynopterus sphinx (Vahl, 1797) oatmeal, raisins and bacon in a ratio of 6 : 2 : 2 : 1. In We caught one specimen, see Table 1 for measure- 34 Mammal Study 28 (2003) Table 1. Summary statistics (mean ± one standard deviation, observed range, number of specimens) for external and crania-dental measurements of three species of bat collected at Mt. Tay Con Linh II. Measurement Cynopterus sphinx Rousettus leschenaulti Sphaerias blanfordi Head and body length 82 97 83 ± 4.3 75–90 (43) Tail length 13 13 0 (43) Hindfoot length 15 16 14 ± 1.1 12–16 (43) Ear length 20 20 19 ± 1.1 17–22 (43) Forearm length 72 83 57 ± 1.8 52–61 Tibia length 28 36 22 ± 1.1 19–24 (43) Weight 43 69 31 ± 3.3 23–39 (43) Condylobasal length 31.3 35.8 27.6 ± 0.8 26.1–28.8 (16) Zygomatic breadth 19.7 21.5 17.4 ± 0.8 16.1–18.5 (16) Braicase breadth 12.9 14.3 12.5 ± 0.3 7.7–8.6 (16) Interorbital constriction 5.9 7.9 5.2 ± 0.3 4.5–5.9 (16) Canine to last upper molar* 11.3 14.3 9.8 ± 0.4 9.3–10.6 (16) Breadth across M1 –M1 8.8 10.2 8.1 ± 0.3 7.7–8.6 (16) Breadth across C1 –C1 6.7 6.9 6.6 ± 0.3 6.2–7.2 (16) * In Cynopterus and Sphaerias M1 is the last upper molar. In Rousettus M2 is the last upper molar. ments and weight. A similar species, C.