Maxomys surifer tonkinensis Balakirev subsp., 2017

Balakirev, Alexander Evgenievich, Abramov, Alexei Vladimirovich & Rozhnov, Viatcheslav Vladimirovich, 2017, Zavreliella inawaheia Sasa, Kitami & Suzuki 2001, Zoological Studies 56 (6), pp. 1-19 : 15-17

Maxomys surifer tonkinensis Balakirev subsp.

nov.

urn:lsid:zoobank.org:act:7E8A1428-2943-4A06-9FC5-263DD4DCC7F5

Holotype: ZMMU S-194718, adult male, skull, skin, body in ethanol, field number Na-52, genetic voucher Na-52, collected 8 March 2014 by Alexander E. Balakirev.

Type locality: Vietnam, Nghe An Province, Quy Chau District, vicinity of Ban Ke Can Village, 19°31.184'N; 105°10.282'E, altitude 95 m a.s.l.

Paratypes: ZMMU S-194710 (male, body at ethanol, collected 6.03.2014), ZMMU S-194711 (female, skull and skin, collected 7.03.2014), ZMMU S-194712 (male, skull and skin, collected 7.03.2014), ZMMU S-194713 (male, skull and skin, collected 7.03.2014), ZMMU S-194714 (male, skull, collected 7.03.2014), ZMMU S-194715 (male, body at ethanol, collected 8.03.2014), ZMMU S-194716 (male, body at ethanol, collected 8.03.2014), ZMMU S-194717 (male, skull, collected 8.03.2014), ZMMU S-194719 (male, skull, collected 9.03.2014, trapped near Ban Dom1 Village), ZMMU S-194720 (male, skull, collected 9.03.2014, trapped near Ban Dom1 Village), ZMMU S-194721 (female, body at ethanol, collected 9.03.2014), ZMMU S-194722 (male, skull, collected 10.03.2014), ZMMU S-194723 (male, skull, collected 10.03.2014), ZMMU S-194724 (female, skull, collected 10.03.2014), ZMMU S-194725 (male, skull, collected 11.03.2014), ZMMU S-194726 (female, body at ethanol, collected 12.03.2014).

All collected by Alexander E. Balakirev and Tran Quang Tien from the same locality as the holotype or in closest vicinity.

Etymology: The new subspecies is named after Tonkin, the former name of northern part of Eastern Indochina, with the Latin suffix - ensis (belonging to).

Diagnosis: Medium-sized rat, larger on average in its external and cranial measurements than the nominotypical M. surifer with a longer tail (106-115% of body length for most individuals).

Description and comparisons: Head and body length 170-222 mm, tail 193-227 mm, ear 24-29 mm, weight 127-210 g. figure 10 B.

New subspecies differs from the M. s. finis which distributed over southern Indochina in the larger skull sizes and in the relatively short upper and lower toothrows. The most evident morphological features at skull construction are also be noticed the size and shape of incisive foramina. In contrast with M. s. finis, which usually has shorter, reniform openings with clearly pointed cranial edge of notch, M. s. tonkinensis has more elongated foramina with more or less rounded cranial and caudal edges of notch figures 7-9, its somewhat reassemble in shape to the foramina characteristic to representatives of genus Leopoldamys but much wider at caudal side. The most remarkable external feature is the pattern of tail coloration, namely the character of tail tip discoloration. This progressive discoloration, characteristic for all M. surifer starts appreciably earlier than it usually happens with representatives of southern populations, discolorations starts approximately from the middle of tail and terminal one third usually became completely white, whereas for M. s. finis discolorations launched from approximately terminal third with only very tip about 1/5 of tail length being completely discolored.

Distribution: Northern Vietnam from Ha Tinh Province in its extreme south to Ba Vi (Hanoi area) in the north; central Laos (Khammouane and Bolikhamxai provinces). It may be probably found in southernmost Yunnan, China ( Wang 2003) and northern Laos, but its presence there has to be approved by investigation of museum specimens or new field records.

Acknowledgment: This work and the one new subspecies name have been registered with Zoo Bank under urn:lsid:zoobank.org:pub:017C3A9D-9B40-4C8C-A621-7BF5883DD1D7 . This study was realized with the support of the Joint Russian-Vietnamese Tropical Research and Technological Centre, Hanoi, Vietnam. We thank Dr. Victor V. Suntsov (A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia), Dr. Sergey V. Kruskop (Zoological Museum of Moscow State University, Moscow, Russia), Dr. Charles M. Francis (Canadian Wildlife Service, Environment Canada, Ottawa, Canada), Dr. Vu Dinh Thong (Zoological Museum of Institute of Ecology and Biological Resources, Vietnamese Academy of Science and Technology) who allow us to access for samples and museum collections and datasets, Dr. Nguyen Dang Hoi, Dr. Bui Xuan Phuong, Mr. Tran Quang Tien and Ms. Pham Mai Phuong (all from the Joint Russian-Vietnamese Tropical Research and Technological Centre, Hanoi, Vietnam), who made considerable efforts in preparing for a number of expeditions and who supplied us with a significant number of specimens. We also want to express our warmest gratitude to Dr. Kristofer M. Helgen, Mr. Craig Ludwig and Mr. Renee Regan (all from the Smithsonian Institution; National Museum of Natural History, Division of Mammals, Washington, USA) for their kind assistance in the investigation and photography of holotype specimen. Finally, we thank the administrations of Ba Vi, Nam Cat Tien, Bi Dup-Nui Ba, Bu Gia Map, Lo Go Xa Mat, Dong Nai, Phu Quoc and Binh Chau National Parks and Nature Reserves for their aid in the management of our studies. This study was supported in part by the Research Program “Living nature: modern state and problems of development” of the Presidium of the Russian Academy of Sciences, by the Zoological Institute’ Program No.0125-2016- 004, the Russian Foundation for Basic Research (grant 16-04-00085) and the Russian Science Foundation (grant 17-14-01160).

List of abbreviation (not explained in text)

DNA - deoxyribonucleic acid

ICZN - International Code of Zoological Nomenclature

PCR - polymerase chain reaction