Troublesome Trimes: Potential cryptic speciation of the Trimeresurus (Popeia) popeiorum complex (Serpentes: Crotalidae) around the Isthmus of Kra (Myanmar and Thailand)

Abstract

The taxonomic identity of the Trimeresurus (Popeia) popeiorum complex from the Isthmus of Kra and to the north was investigated. Several studies over the last decade have produced several specimens and associated mtDNA sequence data for a variety of individuals of the T. popeiorum and "T. sabahi" complexes. Here, we combine four mitochondrial genes (12S, 16S, ND4, and CytB) from all available specimens in GenBank with the addition of five new specimens collected from the mainland, Tanintharyi Region of Myanmar. Maximum Likelihood and Bayesian analyses identified that T. popeiorum sensu lato is paraphyletic with two geographically distinct clades: a northern clade representing populations from northern Myanmar, Laos and northern Thailand and a southern clade representing samples from the Tanintharyi Region and adjacent west Thailand. While the two clades have considerable genetic distance, they appear to be morphologically identical, leading to the hypothesis that the southern clade represents a cryptic, undescribed species. Because they appear to be cryptic species and the limitation of only five specimens from the southern lineage, this does not permit us to formally describe the new species. In accordance to past molecular studies, we uncovered paraphyly and lack of genetic support for the validity of taxa within the T. sabahi complex. However, we suggest recognizing these populations as subspecies within T. sabahi.

Filling the BINs of life: Report of an amphibian and reptile survey of the Tanintharyi (Tenasserim) Region of Myanmar, with DNA barcode data

“…At the Reserve Forest sites, specimens were identified in field and released after being photographed. § See Mulcahy et al (2017) for a taxonomic treatment of the Trimeresurus in the Tanintharyi. † See Lee et al (2018) .…”

“…Lacking a recent review for the Tanintharyi, we relied on reptile and amphibian checklists and studies of Thailand ( Nabhitabhata et al 2004 , Pauwels et al 2002 , Pauwels and Chan-ard 2006 , Matsui et al 2005a , Vogel et al 2009 , Grismer et al 2010 , Chan-ard and Makchai 2011 , Ohler et al 2011 , Grismer et al 2012 , Sumontha et al 2012 , Grosjean et al 2015a , Grismer et al 2016 , 2017 , Wood et al 2017 , Pauwels et al 2000 , 2009 ), reports from other regions in Myanmar ( Dowling and Jenner 1988 , Zug et al 2006a , b , 2007 ), and recent work in the Tanintharyi (e.g. Wilkinson et al 2012 , Connette et al 2017 , Mulcahy et al 2017 ; Zug et al 2017 ; Lee et al 2018 ). An earlier report by Pauwels et al (2002) for Phang-nga Province, Thailand, was south of the southern tip of Tanintharyi and below the Isthmus of Kra, which is useful for comparison of species that may cross the isthmus and occur in the southernmost Tanintharyi.…”

New freshwater mussel taxa discoveries clarify biogeographic division of Southeast Asia

“…This isthmus is a major biogeographic barrier corresponding to a putative ancient seaway 36,37 that influenced distribution ranges of a plethora of animal and plant taxa 38 and corresponds to the separation of the Oriental (Indo-Burmese) and Sundaland biotas 39 . A growing body of phylogeographic and phylogenetic research indicates that this barrier is reflected through abrupt changes in bird 40 , frog 41 , snake 42 , lizard 43 , giant centipede 44 and spider 45 assemblages around the Isthmus of Kra area. However, such examples are still poorly known among freshwater animals.…”

The discovery of Rock Geckos Cnemaspis Strauch, 1887 (Squamata: Gekkonidae) in the Tanintharyi Region, Myanmar with the description of two new species

“…Our collective knowledge of Myanmar's herpetofauna remains incomplete. Because major portions of the country remain unexplored, there is tremendous potential for both new species discoveries and range extensions (Wogan et al 2008;Wilkinson et al 2012;Lee et al 2015Lee et al , 2018Connette et al 2017;Grismer et al 2017a,b;Grismer et al 2018a,b,c;Mulcahy et al 2017Mulcahy et al , 2018Zug et al 2017;Zaw et al 2019). Recent surveys in remote and understudied areas of Myanmar, such as the Tanintharyi, have yielded numerous herpetofaunal specimens that increase our knowledge of biodiversity in that region (Zug et al 2017;Lee et al 2018;Mulcahy et al 2018), a region under studied since the late 19 th century (Theobald 1868).…”