Taxonomic review of the Asian Horned Frogs (Amphibia: Megophrys Kuhl & Van Hasselt) of Northeast India and Bangladesh previously misidentified as M. parva (Boulenger), with descriptions of three new species

ABSTRACT

Megophrys parva

is currently considered to be among the most widely dispersed species within the genus, however, recent studies have provided compelling evidence that this species represents a complex of morphologically similar, deeply divergent taxa. The focus of this paper is to take a closer look at species from Northeast India (NEI) and Bangladesh that are currently, or were until recently, considered to represent M. parva, now comprising the M. (Xenophrys) megacephala species group. We investigate their troublesome taxonomic histories, identify hidden cryptic species diversity using morphological and molecular data, and resolve many of the historical misidentifications that have led to a proliferation of taxonomic confusion in this group. Molecular analyses extend the geographic distribution of the M. (X.) megacephala species group east into northern Myanmar based on available sequence data.

A detailed redescription of the paralectotypes of M. parva is provided to better define this poorly known species. The geographic distributions of the taxonomically obscure species, M. serchhipii and M. zunhebotoensis, are extended far beyond their respective type localities, and both are considerably better defined taxonomically based on detailed descriptions of referred specimens, and comparison with relevant congeners. Significant geographic range extensions are also provided for the recently described species M. oropedion and M. megacephala. Three new species from the Indian states of Nagaland and Manipur are identified using a combination of morphological characters, supported by significant genetic divergence. Examination of historical specimen collections and scrutiny of published literature provide sufficient evidence to remove M. parva and M. wuliangshanensis from the checklist of Indian species. Previous records of M. parva from Bangladesh are demonstrated to represent M. serchhipii. Recent reports of M. glandulosa and M. robusta from Meghalaya are also revised and are considered to be based on misidentifications of known species from the state. The revised distributions of NEI’s small-sized horned frogs provide insights into the biogeography of the group. One of the newly described species known only from the high-elevation Dzükou Valley, Nagaland, might require immediate conservation action due to increased tourist activity at its type locality.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:CE06A188-88E4-44CD-86A4-A62DD902B0A5

KEYWORDS:

• Anura
• taxonomy
• systematics
• molecular phylogenetics
• conservation

Acknowledgements

The following Indian state forest departments kindly provided specimen collection permits and field support: to SDB: Meghalaya state (FWC.G/173 dated 29 April 2008 and FWC.G/173 dated 11 June 2008; FWC.G/16 dated 19 February 2009 and FWC.G/173 dated 23 March 2009; FWC.G/173/Pt-I dated 13 July 2011), Manipur state (3/22/2006-WL dated 3 March 2009), Nagaland state (FOR/GEN-42/2006 dated 29 May 2007) and Tripura state (F.8(163)/FOR-WL-2001/2012); to RGK Manipur state (3/22/2006-WL/87 dated 27 May 2013) and Nagaland state (No. CWL/Gen/97/102–105 dated 02 May 2013). For logistical support in the field and assistance organising permits RGK thanks the following: Abeio Kire, Bayar Lyngwa, Dimdailung Kamei, Janghemlung Panmei, Kenneth Wallang Machunlung G. Kamei, Late S. Kemp. For their assistance in field surveys and/or logistical support we thank Caesar Sengupta, Kaushik Deuti, Robin Suyesh, Tambor Lyngdoh and family, Tengberth Sangma; RGK thanks Abeio Kire, Dimdailung Kamei, Hesili Kemp, Kariuganhliu Kamei Koza, Lungphun Gangmei, Namthuihemang Gangmei, Peter Maram, Rochunlung S. Kamei, Sangailung K. Kamei, Lt. S. Kemp, Thiuga Thomas Kahmei and Vetso Koza; especially Janghemlung Panmei for providing RGK with a jeep and driver for her Manipur expeditions in July 2015. For access to specimen collections and support during museum visits, we thank Barry Clarke, David Gower, Jeffrey Streicher, and Mark Wilkinson (NHMUK), Kaushik Deuti and K. Venkataraman, and staff of the amphibian sections (ZSI, Kolkata and ZSI/NERC). Gabriela Bittencourt provided photographs of the M. parva paralectotype used in Figure 3.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This research was supported by the following funding: Irish Research Council EMBARK Scholarship to SM and ECT; SUSI Student Maintenance Grant to SM; Thomas Crawford Hayes Trust Research and Travel Fund Scheme to SM; Irish Research Council-Marie Skłodowska-Curie CAROLINE Fellowship [CLNE/2017/482] to SM; University College Dublin Seed Grant to SM and ECT; Council of Scientific & Industrial Research’s (CSIR, India) Senior Research Fellowship [9/45 (1082)/2011-EMR-I] to RGK; Rufford Foundation Small Grant [15255-1] to RGK; Critical Ecosystem Partnership Fund (CEPF/IUCN/CI) Grant for Eastern Himalayan Region [No. 2009-150] to SDB; Department of Science and Technology DU/DST Purse Grant [2009/868] from the Government of India to SDB; Research and Development grants [2007/449, 2011/423, 2015/9677] from the University of Delhi to SDB. We thank the two anonymous reviewers for constructive comments that improved an earlier version of this paper.