[Mammalogy • 2024] Typhlomys taxuansis • A New Species of the Genus Typhlomys (Rodentia: Platacanthomyidae) from Vietnam

 

Typhlomys taxuansis

Balakirev, Phuong & Rozhnov, 2024 

DOI: 10.3897/BDJ.12.e133363

 

Abstract

Background: The paper presents novel findings of little-known species of rodents, the blind tree mice Typhlomys in Son La Province, Vietnam, with the first morphological and genetic characterisation and taxonomical description of the new species, T. taxuansis. The study also summarises all the data available on this genus species distribution, museum collections and notes on its taxonomy, which are important to establish the proper conservation status of the species. An exhaustive map of the findings is provided, along with a refined taxonomic key for all six currently morphologically characterised species of the genus. It is shown that, based on the data available to date, the genus is still far from complete. Most species, apparently, do not need a special conservation measure; their status may be established as Least Concerns and Near Threatened (B1a+2a) and the current population trend is stable (IUCN).

New information: The paper introduced innovative findings regarding lesser-known rodents, the blind tree mice Typhlomys in Son La Province, Vietnam, along with the primary morphological and genetic identification and taxonomic explanation of the novel species T. taxuansis.

Keywords: Southeast Asia, Vietnam, rodents, taxonomy, biodiversity

The holotype of Typhlomys taxuansis, skull, ZMMU S-210284 (field number: BY-60, adult female).
A Dorsal view; B Ventral view; C Lateral view; D Lower jaw, dorsal view; E Lower jaw, lateral view; H M1-M3 upper molars, occlusal pattern, enlarged scale; I m1-m3 lower molars, occlusal pattern, enlarged scale.

A new species of Typhlomys from Ta Xua Nature Reserve, specimen BY-60, adult female, external view.
A Dorsal view; B Ventral view; C Lateral view; D Belly, enlarged scale; E Head and backside, enlarged scale; F Distal half of tail with brush; G Hind foot, dorsal view.

Photo of Alexander E. Balakirev. 

Typhlomys taxuansis sp. nov.

Diagnosis: The new species, morphologically, is most similar to T. daloushanensis, but can be distinguished, based on its dental and skull morphology. Based on genetic diversity, the most relative genetic lineage is T. fengjiensis. It obviously differs from geographically most adjacent species T. chapensis and T. nanus by a more flattened braincase; from all known Typhlomys species, except for T. cinereus, by zygomatic arch with deeper incurve; from T. cinereus by mesofossette on M1 open on both buccal and lingual sides rather than open on the buccal side only; and from T. nanus by posterofossettid on M1 present. The new species further differs from other species, except T. daloushanensis, by anterofossette on M2 present.

Etymology: The specific Latin name taxuansis composed as an adjective refers to its type locality in Ta Xua Nature Reserve, Son La Province, Bac Yen District, Vietnam. Due to the sampling location being the southernmost location currently known for this genus, we suggest “southern blind tree mouse” as the English common name.

Alexander E. Balakirev, Bui Xuan Phuong, Viatcheslav V. Rozhnov. 2024. Typhlomys taxuansis (Rodentia, Platacanthomyidae): New Species of the Genus from northern Vietnam with Notes on conservation status and distribution. Biodiversity Data Journal. 12: e133363.  DOI: doi.org/10.3897/BDJ.12.e133363

[Mammalogy • 2022] Typhlomys huangshanensis • A New Species of the Genus Typhlomys Milne-Edwards, 1877 (Rodentia: Platacanthomyidae) from Chongqing, China

Typhlomys fengjiensis Pu, Chen & Liu, 

in Pu, Wan, Fan, Fu, ... et Liu, 2022. 

 Baidi Blind Mouse | 白帝猪尾鼠  || DOI: 10.24272/j.issn.2095-8137.2021.338 

 

A new species of the genus Typhlomys Milne-Edwards, 1877 (Rodentia: Platacanthomyidae) is described based on 10 specimens collected from Chongqing in southwestern China using integrated taxonomy. Phylogenetic analysis showed that these specimens formed a distinct sister clade to T. daloushanensis Wang and Li, 1996, and differed from all six known Typhlomys species based on Kimura-2-parameter genetic distances of the cytochrome b (cyt b) gene (ranging from 0.122 to 0.215). The new species Typhlomys fengjiensis sp. nov. is most similar to T. daloushanensis in morphology. However, it differs from the latter by the following morphological characters: (1) larger body and skull; (2) deeper incurved zygomatic arch; and (3) mesofossette on first upper molar open on both buccal and lingual sides (vs. inner edge of endoloph closed in T. daloushanensis). The discovery of this new species supports that Typhlomys diversity remains underestimated in southern China.

Sample localities, principal component (PCA) and discriminant function analysis (DFA), phylogenetic tree, divergence times, and species delimitation of Typhlomys, with skull and molar comparisons of Typhlomys sp. 1 and T. daloushanensis, and dorsal, ventral, and lateral views of Typhlomys sp. 1

Typhlomys fengjiensis sp. nov. Pu, Chen, and Liu

  

Diagnosis: The new species is most similar to T. daloushanensis but can be distinguished based on its large body size and skull within the genus. It differs from T. chapensis and T. nanus by more flattened braincase; from all known Typhlomys species, except for T. cinereus, by zygomatic arch with distinct deeper incurve; from T. cinereus by mesofossette on M1 open on both buccal and lingual sides rather than open on buccal side only; and from T. nanus by posterofossettid on M1 present. The new species further differs from other species, except T. daloushanensis, by anterofossette on M2 present.

Etymology: The specific Latin name of the new species refers to its type locality in Fengjie County, Chongqing, China. The sampling location is adjacent to the famous and historic Baidi (White Emperor) City, therefore, we suggest “Baidi Blind Mouse” as the English common name and “白帝猪尾鼠” as the Chinese common name.

Distribution and ecology: The new species is currently known only from the type locality, but may also occur in the adjacent mountainous areas in southwestern Hubei of the southern Yangtze River. Moreover, it may also be distributed in northern Chongqing and northwestern Hubei around the Mt. Bashan region if it can disperse across the Yangtze River, such as T. daloushanensis. The study specimens were captured in mountainous forests with bamboo underbrush adjacent to roads at mid-altitudes (1 579–1 883 m a.s.l.). Sympatric species include Blarinella cf. quadraticauda, Chodsigoa smithii, Anourosorex squamipes, Crocidura vorax, Uropsilus gracilis, Apodemus draco, Niviventer lotipes, and Eothenomys eleusis.

...

  

Ying-Ting Pu, Tao Wan, Rong-Hui Fan, Chang-Kun Fu, Ke-Yi Tang, Xue-Long Jiang, Bao-Wei Zhang, Ting-Li Hu, Shun-De Chen and Shao-Ying Liu. 2022. A New Species of the Genus Typhlomys Milne-Edwards, 1877 (Rodentia: Platacanthomyidae) from Chongqing, China. Zoological Research. 43(3); 413-417. DOI: 10.24272/j.issn.2095-8137.2021.338 

[Mammalogy • 2021] Typhlomys huangshanensis • Molecular and Morphological Evidence for A New Species of the Genus Typhlomys (Rodentia: Platacanthomyidae) from China

Typhlomys huangshanensis Hu & Zhang

in Hu, Cheng, Xu, ... et Zhang, 2021. 

Huangshan Blind Mouse | 黄山猪尾鼠 || DOI: 10.24272/j.issn.2095-8137.2020.132  

 

Abstract

In this study, we reassessed the taxonomic position of Typhlomys (Rodentia: Platacanthomyidae) from Huangshan, Anhui, China, based on morphological and molecular evidence. Results suggested that Typhlomys is comprised of up to six species, including four currently recognized species (Typhlomys cinereus, T. chapensis, T. daloushanensis, and T. nanus), one unconfirmed candidate species, and one new species (Typhlomys huangshanensis sp. nov.). Morphological analyses further supported the designation of the Huangshan specimens found at mid-elevations in the southern Huangshan Mountains (600 m to 1 200 m a.s.l.) as a new species.

Keywords: Morphology,  Phylogenetics,  Species delimitation,  Taxonomy

Figure  1.  Phylogenetic tree, species delimitation, and principal component and discriminant function analysis of Typhlomys, with skulls and dorsal views of Typhlomys huangshanensis sp. nov. and molar comparisons of five species
A: Bayesian phylogenetic trees derived from cyt b (a), GHR (b), IRBP (c), and concatenated nuclear and mitochondrial (d) sequences. Letters near branches correspond to different species: A: T. chapensis; B: T. nanus; C: T. daloushanensis; D: T. sp. 2; E: T. cinereus; F: T. sp. 1. B: Species delimitation using PTP (a) and BPP (b), and nuclear gene species trees reconstructed with *BEAST. Node numbers are posterior probabilities (upper) and median ages of divergence times (lower). C: Results of principal component analysis (PCA) (a) and discriminant function analysis (DFA) (b). D: Right upper and lower molars of Typhlomys huangshanensis sp. nov. (holotype, AE1902HS03) (a), T. nanus (KIZ 033585) (b), T. chapensis (KIZ 033593) (c), T. daloushanensis (KIZ 033556) (d), and T. cinereus (USNM 141495) (e). E: Ventral, dorsal, and lateral views of skull and lingual side of mandibles of Typhlomys huangshanensis sp. nov. a: Female (paratype, AE1901HS01); b: male (holotype, AE1902HS03). F: Dorsal views of skin of holotype (upper) and paratype (lower). Except for Typhlomys huangshanensis sp. nov., cheek teeth figures of above species were obtained from Cheng et al. (2017).

A: Bayesian phylogenetic trees derived from cyt b (a), GHR (b), IRBP (c), and concatenated nuclear and mitochondrial (d) sequences. Letters near branches correspond to different species: A: T. chapensis; B: T. nanus; C: T. daloushanensis; D: T. sp. 2; E: T. cinereus; F: T. sp. 1.
B: Species delimitation using PTP (a) and BPP (b), and nuclear gene species trees reconstructed with *BEAST. Node numbers are posterior probabilities (upper) and median ages of divergence times (lower).
C: Results of principal component analysis (PCA) (a) and discriminant function analysis (DFA) (b). 

D: Right upper and lower molars of  Typhlomys huangshanensis sp. nov. (holotype, AE1902HS03) (a), T. nanus (KIZ 033585) (b), T. chapensis (KIZ 033593) (c), T. daloushanensis (KIZ 033556) (d), and T. cinereus (USNM 141495) (e).
E: Ventral, dorsal, and lateral views of skull and lingual side of mandibles of Typhlomys huangshanensis sp. nov. a: Female (paratype, AE1901HS01); b: male (holotype, AE1902HS03).
F: Dorsal views of skin of holotype (upper) and paratype (lower).

Except for Typhlomys huangshanensis sp. nov., cheek teeth figures of above species were obtained from Cheng et al. (2017).

Typhlomys huangshanensis Hu & Zhang, sp. nov.

 

Type locality: Monkey Valley of Huangshan Mountains (N30.119, E118.306, 710 m a.s.l.), Tangkou Township, Huangshan City, Anhui Province, China. The specimen was deposited in the Biological Museum of Anhui University, Anhui, China.

 

Diagnosis: The new species can be distinguished by a flattened braincase rather than the domed braincases of T. nanus and T. chapensis. It has a shorter skull than T. daloushanensis and a narrower interorbital breadth than T. chapensis. Its hind feet are covered with black hair, differing from the yellowish-white hair of T. daloushanensis. It has a longer upper molar than T. cinereus. In the new species, the anterofossettes on M1 are narrower than those in T. cinereus, and the anterofossettid of M2 is missing or inconspicuous.

Ecology and habitat: The specimens were captured from a mixed evergreen and deciduous broad-leaved forest belt. Other sympatric small mammals included Apodemus agrarius, Apodemus draco, Callosciurus erythraeus, Micromys minutus, and Crocidura anhuiensis (Wang, 1990; Zhang et al., 2019).

Distribution: Typhlomys huangshanensis sp. nov. is currently known from the Huangshan and Qingliangfeng mountains, Anhui Province, China. The known elevational range is 710–1 303 m a.s.l.. It might occur in other mountain areas in southern Anhui and western Zhejiang.

Etymology: The specific name refers to its type locality, i.e., Huangshan Mountains, Anhui Province, China. We suggest the English common name as “Huangshan Blind Mouse” and the Chinese common name as “黄山猪尾鼠”.

 

Ting-Li Hu, Feng Cheng, Zhen Xu, Zhong-Zheng Chen, Lei Yu, Qian Ban, Chun-Lin Li, Tao Pan and Bao-Wei Zhang. 2021. Molecular and Morphological Evidence for A New Species of the Genus Typhlomys (Rodentia: Platacanthomyidae). Zoological Research. 42(1); 100-107. DOI: 10.24272/j.issn.2095-8137.2020.132  

 twitter.com/ArloHinckley/status/1354354623021264901

[Mammalogy • 2017] Typhlomys chapensis • A Blind Climber: The First Evidence of Ultrasonic Echolocation in Arboreal Mammals

Typhlomys chapensis Osgood, 1932

Panyutina, Kuznetsov, Volodin, et al., 2017.

DOI: 10.1111/1749-4877.12249 

Abstract

 The means of orientation is studied in the Vietnamese pygmy dormouse Typhlomys chapensis, a poorly known enigmatic semi-fossorial semi-arboreal rodent. Data on eye structure are presented, which prove that Typhlomys (translated as "the blind mouse") is incapable of object vision – the retina is folded and retains no more than 2 500 ganglion cells in the focal plane, and the optic nerve is subject to gliosis. Hence, Typhlomys has no other means for rapid long-range orientation among tree branches other than echolocation. Ultrasonic vocalization recordings at the frequency range of 50-100 kHz support this hypothesis. The vocalizations are represented by bouts of up to 7 more or less evenly-spaced and uniform frequency-modulated sweep-like pulses in rapid succession. Structurally, these sweeps are similar to frequency-modulated ultrasonic echolocation calls of some bat species, but they are too faint to be revealed with a common bat detector. When recording video simultaneously with the ultrasonic audio, a significantly greater pulse rate during locomotion compared to that of resting animals has been demonstrated. Our findings of locomotion-associated ultrasonic vocalization in a fast-climbing but weakly-sighted small mammal ecotype add support to the "echolocation-first theory" of pre-flight origin of echolocation in bats.

 Key words: ultrasonic echolocation, locomotor behaviour, arboreal locomotion, reduced eyes, Typhlomys, Rodentia

Figure 1 Vietnamese pygmy dormouse Typhlomys chapensis. Its reduced eyes are reflected in the generic name, which means “the blind mouse.”

Concluding remarks. The major limitations of our study were the small number of live individuals to experiment with and the poor quality of dead specimens for histology. This is due to the extreme rarity of the Vietnamese pygmy dormouse, or "blind mouse" in nature. That is why our conclusions, though rather convincing, are still preliminary. Additional research is required to describe in detail the acoustic patterns of ultrasonic pulses and bouts in Typhlomys and to compare them with the known acoustics of bats and with non-echolocation ultrasonic calls of other rodents. A remaining question is the mechanism of signal production – is it located in the larynx? and is the animal entirely incapable to communicate in the human-audible range indeed? It will be of interest to investigate the degree of eye degeneration and development of echolocation in a closely related and very similar species, the Chinese pygmy dormouse – Typhlomys cinereus.

Aleksandra A. Panyutina, Alexander N. Kuznetsov, Ilya A. Volodin, Alexey V. Abramov and Irina B. Soldatova. 2017. A Blind Climber: The First Evidence of Ultrasonic Echolocation in Arboreal Mammals. Integrative Zoology. 12(2); 172–184.  DOI: 10.1111/1749-4877.12249

ResearchGate.net/publication/311760839_A_blind_climber_The_first_evidence_of_ultrasonic_echolocation_in_arboreal_mammals

 Video: Blind mouse navigates like a bat sciencemag.org/news/2017/01/video-blind-mouse-navigates-bat

Blind climber science.sciencemag.org/content/355/6322/258.5

An echolocating dormouse could reveal the origins of one of nature's coolest superpowers http://po.st/YfQ1MK  @SmithsonianMag

Rare rodent is the first tree-climbing mammal known to echolocate like a bat | MNN  mnn.com/earth-matters/animals/stories/rare-rodent-first-tree-climbing-mammal-known-echolocate-bat

[Mammalogy • 2017] Phylogeny and Systematic Revision of the Genus Typhlomys (Rodentia, Platacanthomyidae), with Description of A New Species; Typhlomys nanus

Typhlomys nanus

Cheng, He, Chen, Zhang, Wan,  Li, Zhang & Jiang. 2017

kiz.CAS.cn DOI:  10.1093/jmammal/gyx016  

Abstract

The “blind mouse” genus, Typhlomys, is an ancient taxon in the family Platacanthomyidae, comprising 2 living species and 4 living subspecies. We sequenced 3 mitochondrial (CytB, COI, and ND2) and 2 nuclear (GHR and IRBP) gene segments to estimate the phylogenetic relationships of the species and subspecies, and to delimit species boundaries. We also evaluated patterns of morphological and morphometric variation of the skull. The molecular results suggest at least 5 species are present, corresponding to the 2 recognized species (Typhlomys cinereus and T. chapensis), 1 species previously considered a subspecies (T. cinereus daloushanensis), 1 new species (Typhlomys nanus sp. nov.), and 1 putative new species, for which we lack adequate morphological specimens. We also determined that the subspecies Typhlomys cinereus jingdongensis is conspecific with T. chapensis. Diversification of the genus occurred in the late Miocene and Pliocene. The new species, T. nanus, is distributed in eastern and northeastern Yunnan at middle to high elevations (2,000 m to > 3,000 m above sea level). Interestingly, we detected a frameshift mutation within the IRBP gene, which is the 1st molecular evidence for the degradation of vision.

Keywords: frameshift mutation, interphotoreceptor retinoid-binding protein (IRBP), Platacanthomyidae, species delimitation, Typhlomys

Fig. 2.— Dorsal, ventral, and lateral external views of the skin of the holotype of Typhlomys nanus (KIZ 033585). 

Feng Cheng, Kai He, Zhong-Zheng Chen, Bin Zhang, Tao Wan, Jia-Tang Li, Bao-Wei Zhang and Xue-Long Jiang. 2017. Phylogeny and Systematic Revision of the Genus Typhlomys (Rodentia, Platacanthomyidae), with Description of A New Species.  Journal of Mammalogy.  98(3); 731-743. DOI:  10.1093/jmammal/gyx016 

A New Species of Blind Mouse Was Found in Yunnan, China

http://english.kiz.cas.cn/Research/rp/201705/t20170502_176552.html

[Mammalogy • 2014] An enigmatic Pygmy Dormouse: Molecular and Morphological Evidence for the Species Taxonomic Status of Typhlomys chapensis (Rodentia: Platacanthomyidae)

  Typhlomys chapensis (Osgood 1932)

Vietnamese Pygmy Dormouse [or Soft-furred Tree Mouse] 

Figure 4. Typhlomys cinereus. Adult female from Sa Pa, Lao Cai Province, northern Vietnam.

Photographed by A. V. Abramov | doi: 10.3897/zookeys.164.1785

ABSTRACT 

Background: The taxonomic position of enigmatic pygmy dormouse Typhlomys (Rodentia: Platacanthomyidae) from Vietnam is reconsidered based on both morphology and sequence data. 

Results: The analysis of mitochondrial and nuclear genes has shown that the pygmy dormouse from Lao Cai Province of northern Vietnam belongs to a distinct phylogenetic lineage of Typhlomys. The DNA analysis has demonstrated a strong genetic difference (0.245 to 0.252 for the cytochrome oxidase gene (COI), 0.079 to 0.082 for interphotoreceptor retinoid-binding protein gene (IRBP), and 0.028 for the growth hormone receptor gene (GHR) between this lineage and the sample from South China. Multivariate analysis of cranial and dental data, as well as of some external characters, has also separated the Vietnamese population from the pygmy dormouse from Fujian in southern China, the type locality of Typhlomys cinereus (Bull Soc Philomath Paris 12:8–10, 1877). 

Conclusions: Both genetic and morphological data confirm that there is a second species, Typhlomys chapensis (Field Mus Nat Hist Zool Ser 18:193–339, 1932), in the heretofore monotypic genus Typhlomys.

 Alexei V Abramov, Alexander E Balakirev and Viatcheslav V Rozhnov. 2014. An enigmatic Pygmy Dormouse: Molecular and Morphological Evidence for the Species Taxonomic Status of Typhlomys chapensis (Rodentia: Platacanthomyidae). Zoological Studies. 53:34. DOI: 10.1186/s40555-014-0034-2

researchgate.net/publication/264275000_An_enigmatic_pygmy_dormouse_molecular_and_morphological_evidence_for_the_species_taxonomic_status_of Typhlomys chapensis_%28Rodentia_Platacanthomyidae%29

Alexei V. Abramov, Vladimir M. Aniskin and Viatcheslav V. Rozhnov. 2012. Karyotypes of two rare rodents, Hapalomys delacouri and Typhlomys cinereus (Mammalia, Rodentia), from Vietnam. ZooKeys. 164: 41–49, DOI:  10.3897/zookeys.164.1785

http://www.cokesmithphototravel.com/yunnan-expedition.html